openinverter.org wiki - User contributions [en]

Main Page Old

2019-04-12T06:48:23Z

Dmpitsch:

Welcome to the openinverter.org Wiki Site.

The open inverter project consists of some reference designs for the [[Main Board Version 2|control hardware]] using an STM32F103, the inverter firmware, and an easy to use web interface. Other hardware variants include [https://github.com/damienmaguire/ drop in boards for Tesla] small and large drive units.

If you have received a kit you are probably looking for [[Schematics and Instructions|build instructions]].

If you want to tune your inverter check the [[Parameters|parameter description]].

You might also want to set up [[CAN communication|CAN communication]] or use the inverter as a [[Battery Charging|battery charger]] also.

= Hardware =
* [[Main Board Version 3]]
* [[Main Board Version 2]]
* [[Main Board Version 1]]
* [[Sense Boards]]
* [[Gate Driver]]
* [[Hardware Theory of Operation]]
* [[Sensor Board|Legacy Sensor Board]]
= Software =
* [[Software Theory of Operation]]
* [[CAN communication]]
* [[Parameters]]
* [[Downloads]]
* [[Errors]]
= Inverter Kits =
* [[Features]]
* [[Schematics and Instructions]]
* [[Battery Charging]]
= Tesla Boards =
Currently, there are two boards available designed specifically to run the drive units found in the Tesla Model S and Model X electric vehicles.
The Large drive unit (LDU) logic board and Small drive unit (SDU) logic board. The LDU board is designed to run the large rear drive unit found in the Model S and X. Both the standard and performance (sport) version. The SDU board is designed to run the small drive units ,both front and rear.
Both designs are based on the openinverter system and use the exact same firmware and web interface / wifi connectivity as the standard products.
A variant of the LDU found in the Mercedes B class ev can also be used. 
In keeping with the open source philosophy, all designs including full schematics, pcb layouts, BOMs and Gerber files can be found on Github : 
https://github.com/damienmaguire 
Fully built and tested and bare pcb boards are available from the EVBMW webshop : 
http://www.evbmw.com/index.php/evbmw-webshop 
Support for these boards will be provided via the OpenInverter forum and a full body documentation will be built up here on the Wiki over time. 

= Conversion Projects =
* [[VW Polo 86C Conversion]]
= General =
* [[Configuration Files]]

Draft:Main Page

2019-03-30T04:20:20Z

Dmpitsch: Initial creation of Draft:Main Page

Main Page Old

2019-03-30T02:36:06Z

Dmpitsch:

Main Page Old

2019-03-30T02:35:19Z

Dmpitsch: Added content migrated from openinverter.org/docs/

Main Page - Under Development

2019-03-30T02:31:01Z

Dmpitsch:

VW Polo 86C Conversion

2019-03-30T02:30:09Z

Dmpitsch: Added Polo images

[[File:Polo front.jpg|thumb|Polo Front]]
[[File:Polo motor inverter.jpg|thumb|Polo Motor Inverter]]
[[File:Polo front batteries.jpg|thumb|Polo Front Batteries]]
[[File:Polo rear batteries.jpg|thumb|Polo Rear Batteries]]

In November 2008 I picked up the idea of converting a regular ICE car to an electric car. The main reason was back then (and still is) a strong interest in the underlying technology. Therefor I didn't want to use existing products but roll my own. For propulsion I chose an industrial ACIM for its simplicity and availability. To drive such a motor from a battery pack, an inverter is needed. It converts DC current to a rotating 3-phase current which makes the motor spin.

I chose the LiFePo4 battery technology for it is currently the best compromise between cost, weight and power density and offers the best cycle life.

Like all lithium cells they need to be monitored for over and under-voltage. Therefor I developed a monitoring system that measures the voltage of every single cell and transmits that information wireless using infrared light pulses.

Over a timespan of 6 years I "built my dream" and got it approved by the German TÜV Nord. That means it also passed the EMC test i.e. a test that ensures that no other electronic equipment is disturbed by the car.

3 of those 6 years (part time, while attending a normal day job) I spent developing the inverter. Read up on the history on the diyelectriccar forum. I spent another year and a half building a prototype car and another year and a half building the actual car (VW Polo 86C) and developing the BMS. All that included the help of many others.

With all the materials ready and all the development done I'd estimate a conversion time of 2 weeks when converting the same or a very similar car. It's the unexpected and unknown that uses a lot of time: taking stuff apart again and again, waiting for parts to arrive etc.

I decided to make the inverter design available to everyone. AC inverters are considered complicated and mysterious. For that reason many people are scared away from the beautiful AC technology. I'm hoping that I can contribute a tiny bit to making inverters less mysterious.

You can build your own 3-phase motor controller with the material presented here. I'm also offering hardware kits that save you the trouble of ordering parts from different suppliers. You also support the development of the project by ordering a kit.

File:Polo rear batteries.jpg

2019-03-30T02:26:03Z

Dmpitsch:

File:Polo front batteries.jpg

2019-03-30T02:25:36Z

Dmpitsch:

File:Polo motor inverter.jpg

2019-03-30T02:25:07Z

Dmpitsch:

File:Polo front.jpg

2019-03-30T02:24:42Z

Dmpitsch:

VW Polo 86C Conversion

2019-03-30T02:22:28Z

Dmpitsch: Initial Draft

[[File:main_board_v2.jpg|thumb|Main board]]In November 2008 I picked up the idea of converting a regular ICE car to an electric car. The main reason was back then (and still is) a strong interest in the underlying technology. Therefor I didn't want to use existing products but roll my own. For propulsion I chose an industrial ACIM for its simplicity and availability. To drive such a motor from a battery pack, an inverter is needed. It converts DC current to a rotating 3-phase current which makes the motor spin.

I chose the LiFePo4 battery technology for it is currently the best compromise between cost, weight and power density and offers the best cycle life.

Like all lithium cells they need to be monitored for over and under-voltage. Therefor I developed a monitoring system that measures the voltage of every single cell and transmits that information wireless using infrared light pulses.

Over a timespan of 6 years I "built my dream" and got it approved by the German TÜV Nord. That means it also passed the EMC test i.e. a test that ensures that no other electronic equipment is disturbed by the car.

3 of those 6 years (part time, while attending a normal day job) I spent developing the inverter. Read up on the history on the diyelectriccar forum. I spent another year and a half building a prototype car and another year and a half building the actual car (VW Polo 86C) and developing the BMS. All that included the help of many others.

With all the materials ready and all the development done I'd estimate a conversion time of 2 weeks when converting the same or a very similar car. It's the unexpected and unknown that uses a lot of time: taking stuff apart again and again, waiting for parts to arrive etc.

I decided to make the inverter design available to everyone. AC inverters are considered complicated and mysterious. For that reason many people are scared away from the beautiful AC technology. I'm hoping that I can contribute a tiny bit to making inverters less mysterious.

You can build your own 3-phase motor controller with the material presented here. I'm also offering hardware kits that save you the trouble of ordering parts from different suppliers. You also support the development of the project by ordering a kit.

Main Page - Under Development

2019-03-30T02:14:57Z

Dmpitsch: Added internal and external links

Main Page - Under Development

2019-03-30T01:48:32Z

Dmpitsch: Added original Main Page content

Welcome to the openinverter.org Wiki Site.

The open inverter project consists of some reference designs for the control hardware using an STM32F103, the inverter firmware, and an easy to use web interface. Other hardware variants include drop in boards for Tesla small and large drive units.

If you have received a kit you are probably looking for build instructions.

If you want to tune your inverter check the parameter description.

You might also want to set up CAN communication or use the inverter as a battery charger also.

If you need help with your EV conversion check out my consulting offers.

Finally, if you want to support the project visit the shop, become a Patron or send donations to paypal 'at' johanneshuebner.com .

= Hardware =
* [[Main Board Version 3]]
* [[Main Board Version 2]]
* [[Main Board Version 1]]
* [[Sense Boards]]
* [[Gate Driver]]
* [[Hardware Theory of Operation]]
* [[Sensor Board|Legacy Sensor Board]]
= Software =
* [[Software Theory of Operation]]
* [[CAN communication]]
* [[Parameters]]
* [[Downloads]]
* [[Errors]]
= Inverter Kits =
* [[Features]]
* [[Schematics and Instructions]]
* [[Battery Charging]]
= General =
* [[Configuration Files]]
= Tesla Boards =

Downloads

2019-03-29T05:43:11Z

Dmpitsch: Added hyperlinks

The firmware source code and binaries, schematics and various tools are now available on my github.
* [https://github.com/jsphuebner/stm32-sine/releases/latest/ Latest firmware]
* [https://github.com/jsphuebner/tumanako-inverter-fw-bootloader/releases/latest/ Latest boot loader]
* [https://github.com/jsphuebner/esp8266-web-interface/ Latest web ESP8266 interface]
Also check out this [https://github.com/poofik/Huebner-Inverter/ frontend]

Parameters

2019-03-29T05:35:33Z

Dmpitsch: Added fweak image

The inverter can be adapted to many kinds of motors, battery packs and driver preferences by changing parameters.

== Motor Parameters ==
The parameters to adjust the inverter to the motor are boost, fweak, fslipmin, fslipmax, polepairs, fmin, fmax and numimp.

They can be deduced from the motors nameplate or by trying which feels best. For illustration we will assume a bus voltage of 500V and a 4-pole (p=2) motor with a nominal speed of n=1450rpm@f=50Hz and 230V. With 500V DC an AC voltage of 500/1.41=355V can be generated.

'''boost''' is the digital amplitude of the sine wave at motor startup. It is needed to overcome the motors ohmic resistance. Digital amplitude is an internal quantity. 0 means no voltage is generated at all, 37813 means the full possible voltage is generated.

Example: boost=1700

At full throttle an effective voltage of 1700/37813*355=16V is generated. The best way to find a feasible value is to optimize it in the finished car. Start with the default value and increase until you get a good startup.

'''fweak''' is the frequency at which the full possible voltage is generated. It is also the point of the highest motor power. Beyond fweak torque will decrease to the square of frequency and thus power will decrease linear with frequency.

A starting point for fweak is the motors nameplate:

[[File:Fweak.png]]

With our illustration motor fweak=355/230*50=77Hz. fweak can be configured lower than that resulting in more torque at the low end.

'''fslipmin'''/'''fslipmax''' is the slip frequency at which the motor is run at minimum/maximum throttle. fslipmin is set to the motors optimal slip frequency which can be deduced from the nameplate. fslipmin=f-p*n/60. With our illustration motor fslipmin=50-2*1450/60=1.66Hz. fslipmax can be set as high as breakdown torque which is not found on the nameplate. So its best found experimental starting with 2*fslipmin. If set too high the motor will start to rock violently on startup, possibly tripping the over current limit.

'''polepairs''' is set to p, 2 in our example.

'''fmin''' should be set just below fslipmin.

'''fmax''' is used to limit the speed of the motor. The default 200Hz would result in a maximum speed of about 6000rpm.

'''ampmin''' Is the minimum relative amplitude fed to the motor. At very low amplitudes the motor does not generate any noticable torque and throttle travel is wasted that does nothing. Find out a good value by experimenting.

== Inverter Parameters ==
'''pwmfrq''' Sets the frequency at which the IGBTs are switched on and off. The faster the switching the higher the losses in the inverter and the lower the losses in the motor. The maximum frequency is also limited by the driver boards as explained here.

'''pwmpol''' Sets the polarity of the PWM signals, active high or active low. Do not touch this parameter if you don't know what you're doing. When configured inversely it will blow up your power stage immediatly if connected to a potent power source like batteries.

'''deadtime''' The time between switching off one IGBT and switching on the other. 28=800ns, 63=1.5µs. More values can be found in the STM32 data sheet. Make sure to test the deadtime at low power levels. Setting the deadtime too low while operating of a potent power source can blow up your power stage!

== Parameter Reference ==
The following parameters currently exist to customize the controller software. Type
set
to change it. Type
get
to get the current value.

Parameters are internally stored with 5 binary fraction digits. That means there are 32 possible values after the decimal point. So when you set a value of 0.35 you might end up with 0.33.
{| class="wikitable"
|'''Name'''
|'''Unit'''
|'''Min'''
|'''Max'''
|'''Default'''
|'''Description'''
|-
| colspan="6" |'''Motor'''
|-
|boost
|dig
|0
|37813
|1700
|0 Hz Boost in digit. 1000 digit ~ 2.5%
|-
|fweak
|Hz
|0
|400
|67
|Frequency where V/Hz reaches its peak
|-
|udcnom
|V
|0
|1000
|0
|Nominal voltage for fweak and boost. fweak and boost are scaled to the actual dc voltage. 0=don't scale
|-
|fpconst
|Hz
|0
|400
|400
|Frequency where slip frequency is derated to form a constant power region. Only has an effect when < fweak
|-
|fslipmin
|Hz
|0
|100
|1
|Slip frequency at minimum throttle
|-
|fslipmax
|Hz
|0
|100
|3
|Slip frequency at maximum throttle
|-
|polepairs
|
|1
|16
|2
|Pole pairs of motor (4-pole motor: 2 pole pairs)
|-
|respolepairs
|
|1
|16
|1
|Pole pairs of resolver
|-
|encflt
|
|0
|16
|4
|Filter constant between pulse encoder and speed calculation. Makes up for slightly uneven pulse distribution
|-
|encmode
|
|0
|4
|0
|0=single channel encoder, 1=quadrature encoder,
2=quadrature /w index pulse,
3=SPI (deprecated)
4=Resolver
|-
|fmin
|Hz
|0
|400
|1
|Below this frequency no voltage is generated
|-
|fmax
|Hz
|0
|400
|200
|At this frequency slip is commanded 0 to avoid further acceleration
|-
|numimp
|Imp/rev
|8
|8192
|60
|Pulse encoder pulses per turn
|-
|dirchrpm
|rpm
|0
|2000
|100
|Motor speed at which direction change is allowed
|-
|dirmode
|
|0
|1
|1
|0=button (momentary pulse selects forward/reverse), 1=switch (forward or reverse signal must be constantly high)
|-
|syncofs
|dig
|0
|65535
|0
|Phase shift of sine wave after receiving index pulse
|-
|snsm
|
|2
|3
|2
|Motor temperature sensor. 2=KTY83, 3=KTY84
|-
| colspan="6" |'''Inverter'''
|-
|pwmfrq
|
|0
|3
|2
|PWM frequency. 0=17.6kHz, 1=8.8kHz, 2=4.4kHz, 3=2.2kHz. Needs PWM restart
|-
|pwmpol
|
|0
|1
|0
|PWM polarity. 0=active high, 1=active low. DO NOT PLAY WITH THIS!
Needs PWM restart
|-
|deadtime
|dig
|0
|255
|28
|Deadtime between highside and lowside pulse. 28=800ns, 56=1.5µs. Not always linear, consult STM32 manual. Needs PWM restart
|-
|ocurlim
|A
| -65535
|65535
|100
|Hardware over current limit. RMS-current times sqrt(2) + some slack
|-
|minpulse
|dig
|0
|4095
|1000
|Narrowest or widest pulse, all other mapped to full off or full on, respectively
|-
|il1gain
|dig/A
|0
|4095
|4.7
|Digits per A of current sensor L1
|-
|il2gain
|dig/A
|0
|4095
|4.7
|Digits per A of current sensor L2
|-
|udcgain
|dig/V
|0
|4095
|6.15
|Digits per V of DC link
|-
|udcofs
|dig
|0
|4095
|0
|DC link 0V offset
|-
|udclim
|V
|0
|1000
|540
|High voltage at which the PWM is shut down
|-
|snshs
|
|0
|1
|0
|Heatsink temperature sensor. 0=JCurve, 1=Semikron
|-
| colspan="6" |'''Derating'''
|-
|bmslimhigh
|%
|0
|100
|50
|Positive throttle limit on BMS under voltage
|-
|bmslimlow
|%
| -100
|0
| -1
|Regen limit on BMS over voltage
|-
|udcmin
|V
|0
|1000
|450
|Minimum battery voltage
|-
|udcmax
|V
|0
|1000
|520
|Maximum battery voltage
|-
|iacmax
|A
|0
|5000
|5000
|Maximum AC current
|-
|idcmax
|A
|0
|5000
|5000
|Maximum DC input current
|-
|idcmin
|A
| -5000
|0
| -5000
|Maximum DC output current (regen)
|-
|throtmax
|%
|0
|100
|100
|Throttle limit
|-
| colspan="6" |'''Charger'''
|-
|chargemode
|
|0
|4
|0
|0=Off, 3=Boost, 4=Buck
|-
|chargecur
|
|0
|50
|0
|Charge current setpoint. Boost mode: charger INPUT current. Buck mode: charger output current
|-
|chargekp
|
|0
|100
|80
|Charge controller gain. Lower if you have oscillation, raise if current set point is not met
|-
|chargeflt
|
|0
|10
|8
|Charge current filtering. Raise if you have oscillations
|-
|chargemax
|%
|0
|99
|90
|Charge mode duty cycle limit. Especially in boost mode this makes sure you don't overvolt you IGBTs if there is no battery connected.
|-
| colspan="6" |'''Throttle'''
|-
|potmin
|dig
|0
|4095
|0
|Value of "pot" when pot isn't pressed at all
|-
|potmax
|dig
|0
|4095
|4095
|Value of "pot" when pot is pushed all the way in
|-
|pot2min
|dig
|0
|4095
|4095
|Value of "pot2" when regen pot is in 0 position
|-
|pot2max
|dig
|0
|4095
|4095
|Value of "pot2" when regen pot is in full on position
|-
|potmode
|
|0
|2
|0
|0=Pot 1 is throttle and pot 2 is regen strength preset,
1=Pot 2 is proportional to pot 1 (redundance)
2=Throttle controlled via CAN
|-
|throtramp
|%/10ms
|0
|100
|100
|Max positive throttle slew rate
|-
|throtramprpm
|rpm
|0
|20000
|20000
|No throttle ramping above this speed
|-
|ampmin
|%
|0
|100
|10
|Minimum relative sine amplitude
|-
|slipstart
|%
|10
|100
|50
|% positive throttle travel at which slip is increased
|-
| colspan="6" |'''Regen'''
|-
|brknompedal
|%
| -100
|0
| -50
|Foot on break pedal regen torque
|-
|brkpedalramp
|%/10ms
|1
|100
|100
|Ramp speed when entering regen. E.g. when you set brkmax to 20% and brkpedal to -60% and brkpedalramp to 1, it will take 400ms to arrive at brake force of -60%
|-
|brknom
|%
|0
|100
|30
|Regen padel travel
|-
|brkmax
|%
|0
|100
|30
|Foot-off regen torque
|-
|brkout
|%
| -100
| -1
| -50
|Activate brake light output at this amount of braking force
|-
|brkrampstr
|Hz
|0
|400
|10
|Below this frequency the regen torque is reduced linearly with the frequency
|-
| colspan="6" |'''Automation'''
|-
|idlespeed
|rpm
| -100
|1000
| -100
|Motor idle speed. Set to -100 to disable idle function. When idle speed controller is enabled, brake pedal must be pressed on start.
|-
|idlethrotlim
|%
|0
|100
|50
|Throttle limit of idle speed controller
|-
|idlemode
|
|0
|1
|0
|Motor idle speed mode. 0=always run idle speed controller, 1=only run it when brake pedal is released, 2=like 1 but only when cruise switch is on
|-
|speedkp
|Hz
|0
|100
|1
|Speed controller gain (Cruise and idle speed). Decrease if speed oscillates. Increase for faster load regulation
|-
|cruisemode
|
|0
|1
|0
|0=button (set when button pressed, reset with brake pedal), 1=switch (set when switched on, reset when switched off or brake pedal)
|-
|speedflt
|dig
|0
|16
|1
|Filter before cruise controller
|-
| colspan="6" |'''Contactor Control'''
|-
|udcsw
|V
|0
|1000
|330
|Voltage at which the DC contactor is allowed to close
|-
|udcswbuck
|V
|0
|1000
|540
|Voltage at which the DC contactor is allowed to close in buck charge mode
|-
|tripmode
|
|0
|2
|0
|What to do with relays at a shutdown event. 0=All off, 1=Keep DC switch closed, 2=close precharge relay
|-
| colspan="6" |'''Auxillary PWM'''
|-
|pwmfunc
|
|0
|2
|0
|Quantity that controls the PWM output. 0=tmpm, 1=tmphs, 2=speed
|-
|pwmgain
|dig/C
|0
|65535
|100
|Gain of PWM output
|-
|pwmofs
|dig
| -65535
|65535
|0
|Offset of PWM output, 4096=full on
|-
| colspan="6" |'''Communication'''
|-
|canspeed
|
|0
|3
|0
|Baud rate of CAN interface 0=250k, 1=500k, 2=800k, 3=1M
|-
|canperiod
|
|0
|1
|0
|0=send configured CAN messages every 100ms, 1=every 10ms
|-
| colspan="6" |'''Testing'''
|-
|fslipspnt
|Hz
| -100
|100
|0
|Slip setpoint in mode 2. Written by software in mode 1
|-
|ampnom
|%
|0
|100
|0
|Nominal amplitude in mode 2. Written by software in mode 1
|}
The following values are available for diagnostic purposes. Type
get
to get the current value. To read more then one you can provide a list like
get il1,il2,udc
{| class="wikitable"
|'''Name'''
|'''Unit'''
|'''Description'''
|-
|version
|
|Firmware version
|-
|opmode
|
|Operating mode. 0=Off, 1=Run, 2=Manual_run, 3=Boost, 4=Buck, 5=Sine, 6=2 Phase sine
|-
|udc
|V
|DC link voltage
|-
|uac
|V
|Calculated AC voltage
|-
|idc
|A
|Calculated DC current
|-
|il1
|A
|AC current L1
|-
|il2
|A
|AC current L2
|-
|il1rms
|A
|RMS current L1
|-
|il2rms
|A
|RMS current L2
|-
|boostcalc
|A
|DC link adjusted boost setting
|-
|fweakcalc
|A
|DC link adjusted fweak setting
|-
|fstat
|Hz
|Stator frequency
|-
|speed
|rpm
|Motor speed
|-
|amp
|dig
|Sine amplitude, 37813=max
|-
|pot
|dig
|Pot value, 4095=max
|-
|pot2
|dig
|Regen Pot value, 4095=max
|-
|potnom
|%
|Scaled pot value, 0 accel
|-
|dir
|
|Rotation direction. -1=REV, 0=Neutral, 1=FWD
|-
|tmphs
|°C
|Heatsink temperature
|-
|tmpm
|°C
|Motor temperature
|-
|uaux
|°C
|Auxiliary voltage (i.e. 12V system). Measured on pin 11 (mprot)
|-
|din_cruise
|
|Cruise Control. This pin activates the cruise control with the current speed. Pressing again updates the speed set point.
|-
|din_start
|
|State of digital input "start". This pin starts inverter operation
|-
|din_brake
|
|State of digital input "brake". This pin sets maximum regen torque (brknompedal). Cruise control is disabled.
|-
|din_mprot
|
|State of digital input "motor protection switch". Shuts down the inverter when =0
|-
|din_forward
|
|Direction forward
|-
|din_reverse
|
|Direction backward
|-
|din_emcystop
|
|State of digital input "emergency stop". Shuts down the inverter when =0
|-
|din_ocur
|
|Over current detected
|-
|din_bms
|
|BMS over voltage/under voltage
|-
|cpuload
|%
|CPU load for everything except communication
|}

File:Fweak.png

2019-03-29T05:34:12Z

Dmpitsch:

Hardware Theory of Operation

2019-03-29T05:30:19Z

Dmpitsch: Added assembled inverter images

[[File:assembled_inverter.jpg|thumb|Assembled Inverter]]
[[File:assembled_inverter_inside.jpg|thumb|Inside View]]
[[File:assembled_inverter_controller.jpg|thumb|Controller]]
[[File:assembled_inverter_gate_driver.jpg|thumb|Gate Driver]]
[[File:igbt_module_schematic.jpg|thumb|IGBT Half Bridge Module]]

In principle, an inverter is a rather simple device. The incoming DC voltage is distributed over 3 "bridges" each of which modulates the DC voltage to a sine wave with variable phase, amplitude and frequency.

Each bridge consists of 2 switches which can be controlled electronically. If the top switch is closed, the output is connected to high voltage, if the bottom switch is closed the output is connected to ground. If both switches are closed the inverter explodes. To set an average output voltage, the switches are toggled a couple of 1000 times per second. The ratio between top and bottom "closed-time" is called ''dutycycle''. So say the incoming DC voltage is '''500V'''. If the duty cycle is 0% the output voltage is 0V. If the duty cycle is 100% the output voltage is 500V. If the duty cycle is 50% the output voltage is 250V and so on.

If this principle is applied to all 3 bridges then 3 arbitrary voltages between 0 and 500V can be produced. The 3 inputs of the motor (commonly called ''L1, L2, L3'') are connected to the 3 outputs of the inverter. So the motor only "sees" the '''voltage difference''' between the outputs. If all 3 operate at the same duty cycle the motor sees 0V. If bridge one produces 300V, bridge 2 produces 200V and bridge 3 produces 250V then the motor sees -100V between L1 and L2, 50V between L2 and L3, and -50V between L3 and L1. Depending on the specifics of the motor according currents flow.

When building an inverter some nasty details show up. Lets go over them.

== The DC bus ==
When I started out building my first inverter I thought "lets ditch those stupid capacitors, the batteries are capacity enough". Not so, theres a reason for this expensive parts. Let me explain with some water. Say you're watering your garden with a hose that has some spraying device on the end which allows you to interrupt the water flow. If you interrupt the flow the hose will rock a bit. Thats because the water somewhere back in the pipe doesn't "know" that you've just closed the valve. So for a short moment the water will keep coming and the pressure inside the hose rises. The longer the hose, the stronger that effect- The same happens when interrupting an electric current flow. You interrupt, the current keeps coming and thus the voltage rises. The switches only withstand a finite voltage. The ones I use are specified for 1200V. With the cable length used in a car the voltage will easily rise above 1200V when switched off and the switch breaks.

To cure this problem the excess current needs to be trapped somewhere. It it must be trapped as close to the switch as possible because any remaining distance is another piece of "hose". Thats what the big round and small cubic capacitors are for. The round ones can take a lot of excess current while the small ones catch the remaing current right at the switches terminal. The closer your DC voltage comes to the breakdown voltage of the switch the more care must be taken to catch the excess current. With a lot of effort you can operate 1200V switches at around 900V. With less effort you can operate them at 700V. So to keep stuff simple the switches need to be oversized.

== Gate drivers ==
The switches are controlled with a small voltage of typically 15V. At 0V the switch is off, at 15V it's on. Keeping the switch on or off is easy. But changing state is rather hard. Just like switching on the light in your kitchen requires some mechanical force. The electric current needed to operate our switches is 2.5A. More serious power electronics even require 40A. So gate drivers for power electronics ''are'' power electronics.

Another challenge is on the high side, i.e. the switch thats connects the output to the high voltage. I stated above that 15V are needed to switch on. 15V in respect to what? In respect to the ''source'' i.e. the output of the high side switch. So as the high side is switched on, its output rises to the high voltage. So the control voltage has to rise with it. Imagine a lift that rises '''while'''you push a button inside it. You better be standing inside the lift as you push the button.

This last aspect presents the third function of a simple gate driver: ''galvanic isolation''. It's like a guy standing in the lift operating it for you. No matter where he is, you can stay where you are. In an inverter thats also a safety issue. You don't want your controller side to be electrically connected to the power side.

More advanced gate drivers take care that bottom and top switch are never closed at the same time and they insert a security margin (called ''deadtime'') between opening one switch and closing the other. They also monitor the voltage over the switch as the switch is closed. If it rises to high then the switch is overloaded and will be opened. This is called ''desaturation detection'' or short ''desat''. The deadtime can be replicated in software, the desat can be (almost) replaced with fast current monitoring.

== Step by Step ==
I'm often sent emails with ebay links to all sorts of IGBT modules. And often they are unusable. What you want is an IGBT half bridge module as depicted above. It is two IGBTs and two diodes in one case.

Next up is capacitor selection. It's hard to give general advise. I always advise against elcaps because of their low ripple current rating. Better use film caps as shown above. If you can get your hands on any cheap and large (meaning above 300µF for filmcaps or 3000µF for elcaps) caps then give it a shot. Watch the DC bus voltage with a scope while running the inverter at load. You don't want to see excessive ringing or spikes. Here are some examples of what you do and don't want to see.

In the power stage depicted above I used 1.5µF snubber caps on each IGBT terminal plus two 420µF film caps. All components have screw terminals with the same width. That makes handling very easy. Everything is bolted onto a pair of alloy strips forming a simple low inductance DC bus.

To suppress high frequency common mode signals you can place a ferrite core around the DC bus or the DC cables. This will give you a better chance to pass EMC compliance tests.

Last but not least place the gate drivers directly onto the corresponding pins of the module. The PCB has been designed to line up. Make use of that. 1cm of wire should be enough!

With the setup depicted above I passed the ECE-R10 EMC compliance test with a good margin. It's not that hard.

File:Igbt module schematic.jpg

2019-03-29T05:19:18Z

Dmpitsch:

File:Assembled inverter inside.jpg

2019-03-29T05:18:56Z

Dmpitsch:

File:Assembled inverter gate driver.jpg

2019-03-29T05:18:35Z

Dmpitsch:

File:Assembled inverter controller.jpg

2019-03-29T05:18:13Z

Dmpitsch:

File:Assembled inverter.jpg

2019-03-29T05:17:44Z

Dmpitsch:

Gate Driver

2019-03-29T05:12:55Z

Dmpitsch: Added gate driver images

[[File:gate_driver.jpg|thumb|Gate Driver Board]]
[[File:schematic_gate_driver.png|thumb|Gate Driver Board Schematic]]

The gate drivers convert the logic level PWM signals to a bipolar signal that can be used to drive the gate of power semiconductors. They also isolate the power section from the control section.

== DC/DC converter ==
To provide power to the power section (the secondary side) isolated DC/DC converters are used. They provide a continues power of 1W. This power limits the PWM switching speed. The input voltage to the converters is 5V and their output voltages are -9V and +15V. (Used to be -15).

The formular is P=Ug²/Rg*(tr+tf)*fPWM with Ug=24V, Rg=4.7Ohms.

Example. tr=50ns, tf=110ns, fPWM=8.8kHz (SKM400GB126)

-> P=24²/4.7*(50ns+110ns)*8800Hz = 0.17W.

Please note, that this formular is an approximation. In the datasheet, together with the tr/tf times a gate resistor is stated in the conditions. If this gate resistor is less then 4.7Ohm of this driver this means that tr and tf will be a bit higher as well. If in doubt, please measure tr and tf with a scope.

== Gate Drive Optocouplers ==
To transmit the logic level signals to the secondary side, Si8261 gate drive isolaters are used. They provide a peak drive current of 4A.

File:Schematic gate driver.png

2019-03-29T05:11:55Z

Dmpitsch:

File:Gate driver.jpg

2019-03-29T05:11:33Z

Dmpitsch:

Sensor Board

2019-03-29T05:01:48Z

Dmpitsch: Added Sensor Board images

[[File:sensor_board.jpg|thumb|Sensor Board]]
[[File:schematic_sensor_board_r2.png|thumb|Sensor Board Schematic R2]]
[[File:schematic_sensor_board_r3.png|thumb|Sensor Board Schematic R3]]

This board was designed to interface JP4 on the main board. It contains the current sensors, a resistive voltage measurement and an input for a temperature sensor. A J-Curve temperature probe is provided with the board.

== Current sensors ==
The provided 400A current sensors need an unipolar supply voltage of 5V. They output 2.5V when idle, i.e. at 0A. At -400A the output is 1V and at 400A the output is 4V.

The board contains an offset/gain stage that converts this to 0-3.3V. As a side effect the signal is not inverted. Now the output is 1.67V when idle, 0V at 400A and 3.3V at -400A. These values are approximations. Therefor the software allows for another offset/gain correction for each current sensor.

== Voltage sensing ==
The voltage sensing uses megaohm resistors to fullfill the isolation requirements from the ECE-100 being 500Ohms/V. As the typical operating voltage of through-hole resistors is 250V, 4 of them are used in series. The high impedance signal is converted to low impedance. This is cheaper than using real galvanic isolation. As a side effect isolation problems can be detected because any resistance in parallel to the sense resistors will affect the reading. The cutoff frequency is about 1Hz.

The formular for the maximum input voltage is

[[File:Formular udc.png]]

== Temperature sensing ==
The temperature sense input has an input impedance of 1.2k. This matches the J-Curve temperature probe and is also the value assumed by the inverter software.

File:Schematic sensor board r3.png

2019-03-29T04:56:45Z

Dmpitsch:

File:Schematic sensor board r2.png

2019-03-29T04:56:25Z

Dmpitsch:

File:Sensor board.jpg

2019-03-29T04:55:54Z

Dmpitsch:

Sense Boards

2019-03-29T04:54:44Z

Dmpitsch:

[[File:voltage_sense_board.jpg|thumb|Voltage Sense Board]]
[[File:schematic_voltage_sense_board.png|thumb|Voltage Sense Board Schematic]]
[[File:current_sense_board.jpg|thumb|Current Sense Board]]
[[File:schematic_current_sense_board.png|thumb|File:Current Sense Board Schematic]]

3 sensing boards provide the inverter with values for the DC link voltage, heat sink temperature and two phase currents.

= Voltage Sense Board =

The voltage sense board uses an Si8920 analog isolator. It converts a voltage of 200mV on the primary (right side on schematic) into around 3V on the secondary side. Since the isolators output is differential we need an opamp circuit to make it single-ended.

The board also provides the connection for the heatsink temperature sensors.

= Current Sense Board =

The current sense board used a Melexis MLX91205 magnetic field sensor. It outputs 2.5V at 0 T and swings between 0.25V and 4.75V at +/-25mT. With a simple resistive divider that is scaled to the 3.3V range. The board is supposed to be mounted directly on the phase output cable or bus bar. The correlation between the phase current and the output swing varies with the distance between the conductor and the chip. With no further spacers the range is about 800A on cable. A busbar needs an additional isolation layer.

Make sure to place the two sense board far apart from each other and any other high current conductor to avoid cross talk.

= Legacy Sensor Board =

Go here for information about the [[Sensor_Board|legacy Tamura/LEM sensor boards]].

Sense Boards

2019-03-29T04:51:00Z

Dmpitsch: Added sense board images

[[File:voltage_sense_board.jpg|thumb|Voltage Sense Board]]
[[File:schematic_voltage_sense_board.png|thumb|Voltage Sense Board Schematic]]
[[File:current_sense_board.jpg|thumb|Current Sense Board]]
[[File:schematic_current_sense_board.png|thumb|File:Current Sense Board Schematic]]

3 sensing boards provide the inverter with values for the DC link voltage, heat sink temperature and two phase currents.

= Voltage Sense Board +

The voltage sense board uses an Si8920 analog isolator. It converts a voltage of 200mV on the primary (right side on schematic) into around 3V on the secondary side. Since the isolators output is differential we need an opamp circuit to make it single-ended.

The board also provides the connection for the heatsink temperature sensors.

= Current Sense Board =

The current sense board used a Melexis MLX91205 magnetic field sensor. It outputs 2.5V at 0 T and swings between 0.25V and 4.75V at +/-25mT. With a simple resistive divider that is scaled to the 3.3V range. The board is supposed to be mounted directly on the phase output cable or bus bar. The correlation between the phase current and the output swing varies with the distance between the conductor and the chip. With no further spacers the range is about 800A on cable. A busbar needs an additional isolation layer.

Make sure to place the two sense board far apart from each other and any other high current conductor to avoid cross talk.

= Legacy Sensor Board =

Go here for information about the [[Sensor_Board|legacy Tamura/LEM sensor boards]].

File:Schematic current sense board.png

2019-03-29T04:39:24Z

Dmpitsch:

File:Schematic voltage sense board.png

2019-03-29T04:37:41Z

Dmpitsch:

File:Voltage sense board.jpg

2019-03-29T04:37:17Z

Dmpitsch:

Main Page - Under Development

2019-03-29T04:34:04Z

Dmpitsch: Added Legacy Sensor Board

Sensor Board

2019-03-29T04:31:44Z

Dmpitsch:

This board was designed to interface JP4 on the main board. It contains the current sensors, a resistive voltage measurement and an input for a temperature sensor. A J-Curve temperature probe is provided with the board.

== Current sensors ==
The provided 400A current sensors need an unipolar supply voltage of 5V. They output 2.5V when idle, i.e. at 0A. At -400A the output is 1V and at 400A the output is 4V.

The board contains an offset/gain stage that converts this to 0-3.3V. As a side effect the signal is not inverted. Now the output is 1.67V when idle, 0V at 400A and 3.3V at -400A. These values are approximations. Therefor the software allows for another offset/gain correction for each current sensor.

== Voltage sensing ==
The voltage sensing uses megaohm resistors to fullfill the isolation requirements from the ECE-100 being 500Ohms/V. As the typical operating voltage of through-hole resistors is 250V, 4 of them are used in series. The high impedance signal is converted to low impedance. This is cheaper than using real galvanic isolation. As a side effect isolation problems can be detected because any resistance in parallel to the sense resistors will affect the reading. The cutoff frequency is about 1Hz.

The formular for the maximum input voltage is

[[File:Formular udc.png]]

== Temperature sensing ==
The temperature sense input has an input impedance of 1.2k. This matches the J-Curve temperature probe and is also the value assumed by the inverter software.

File:Current sense board.jpg

2019-03-29T04:28:50Z

Dmpitsch:

Sensor Board

2019-03-29T04:15:22Z

Dmpitsch: Initial Draft

This board was designed to interface JP4 on the main board. It contains the current sensors, a resistive voltage measurement and an input for a temperature sensor. A J-Curve temperature probe is provided with the board.

== Current sensors ==
The provided 400A current sensors need an unipolar supply voltage of 5V. They output 2.5V when idle, i.e. at 0A. At -400A the output is 1V and at 400A the output is 4V.

The board contains an offset/gain stage that converts this to 0-3.3V. As a side effect the signal is not inverted. Now the output is 1.67V when idle, 0V at 400A and 3.3V at -400A. These values are approximations. Therefor the software allows for another offset/gain correction for each current sensor.

== Voltage sensing ==
The voltage sensing uses megaohm resistors to fullfill the isolation requirements from the ECE-100 being 500Ohms/V. As the typical operating voltage of through-hole resistors is 250V, 4 of them are used in series. The high impedance signal is converted to low impedance. This is cheaper than using real galvanic isolation. As a side effect isolation problems can be detected because any resistance in parallel to the sense resistors will affect the reading. The cutoff frequency is about 1Hz.

The formular for the maximum input voltage is

== Temperature sensing ==
The temperature sense input has an input impedance of 1.2k. This matches the J-Curve temperature probe and is also the value assumed by the inverter software.

File:Formular udc.png

2019-03-29T04:11:24Z

Dmpitsch:

Main Board Version 2

2019-03-29T03:57:30Z

Dmpitsch: Added v2 images

[[File:main_board_v2.jpg|thumb|Main board]]
[[File:mainboard_connections_v2.jpg|thumb|Connections]]
[[File:schematic_main_v2.png|thumb|Schematic]]

The main board is the heart of the inverter system. It contains all the intelligence that is needed to convert the users inputs into motor shaft movement. It also contains all the protection circuitry to avoid damage in case of errornous inputs.

Its distinct features are:

== Digital inputs ==
There are external 8 digital inputs on JP5. A voltage of >7V is interpreted as a logical 1 (high). They all have a cutoff frequency of 40Hz.
# Cruise Control (Pin 5). This input sets the current motor speed as the set point for cruise control. Cruise control is disabled with the Brake input.
# Start (Pin 7). This input starts the inverter operation.
# Brake input (Pin 9). This input is connected to the brake pedal. It sets a configurable negative torque (regen) which overrides the throttle. I.e. if you press both, brake pedal and throttle, the throttle is ignored.
# Motor Protection switch (Pin 11). This input is connected to the thermal protection switch that is embedded into many motors. Its function is to inhibit the PWM signals when the motor overheats. This input directly controls the PWM signals without software interaction. The PWM is enabled as long as this input is high and shut down as soon as it goes low. If your motor does not have such a switch, tie the input high permanently.
# Forward (Pin 13). If this input is high the motor spins forward.
# Reverse (Pin 15). If this input is high the motor spins backward. When neither input is high the motor will not spin at all.
# Emergency Stop (Pin 17). This input has the same function as the motor protection input. It can be used for an emergency stop button. Tie it high otherwise.
# BMS input (Pin 19). This input limits the motor torque (both negative and positive) if a BMS signals an over or undervoltage condition. It is active high, i.e. high means over/undervoltage.
There are two more digital inputs on JP3
# Error input (Pin 13) This pin is pulled high (5V). When pulled low an error is signalled and the PWM is inhibited
# UVLO input (Pin 14) This pin is pulled high (3.3V). When pulled low an error is signalled and the PWM is inhibited

== Digital outputs ==
There are 4 external open collector outputs on JP5.
# DC contactor output (Pin 12) This output is activated when the bus voltage is above a given threshold and the start pin goes high. It is disabled on overcurrent, motor overheat and emergency stop.
# Error output (Pin 14) This output is activated on over current, motor overheat, emergency stop, throttle out of range.
# Voltage output (Pin 16) This output is activated when the bus voltage surpasses an upper or lower threshold.
# Precharge output (Pin 20) This output is activated when the inverter is powered up. It is disabled as soon as the DC contactor is enabled.
# Brake output (Pin 10) This output is high when potnom reaches a certain negative threshold. The purpose is to switch on the brake light on a certain regen level

== PWM outputs ==
There is one external PWM output on JP5, Pin 18. It outputs a duty cycle that is proportional to the motor or heatsink temperature or speed. Its offset and gain is software configurable. The frequency is fixed to 17kHz. It is an open collector output so it can be used with most temperature gauges in cars. It can sink up to 500mA.

There are 6 internal PWM outputs on JP3. Pins 4, 8 and 12 provide a GND connection, Pins 1, 5 and 9 provide 5V. The outputs are 3.3V, 16mA.
# PWM Top phase 1 (Pin 2)
# PWM Bottom phase 1 (Pin 3)
# PWM Top phase 2 (Pin 6)
# PWM Bottom phase 2 (Pin 7)
# PWM Top phase 3 (Pin 10)
# PWM Bottom phase 3 (Pin 11)
There is a configurable dead time between top and bottom outputs.

== Analog Inputs and over-current protection ==
There are 3 external analog inputs on JP5.
# Throttle input, 0-3.3V (Pin 6). Cutoff frequency 16Hz, input resistance 10k.
# Regen pot input, 0-3.3V (Pin 8). Cutoff frequency 16Hz, input resistance 10k.
# KTY83 temperature sensor input (Pin 22 positive, Pin 21 negative). Cutoff frequency 16Hz
There are 4 internal analog inputs on JP4. Pins 5,7 and 10 provide a GND connection, Pin 8,11 and 12 provide stablelized 5V.
# Udc (Pin 4) Bus voltage input. 0-3.3V, cutoff frequency 16Hz
# Il1 (Pin 6) Current phase 1. 0V=-Imax, 1.67V=0A, 3.3V=Imax (software configurable). Cutoff frequency 48kHz.
# Il2 (Pin 9)
# Heatsink temperature (Pin 13)
The two current sensors are used for the programmable hardware over-current protection. A trip limit can be programmed that configures a hardware comparator. When the given current limit is hit, the PWM signals will be shut down without software interaction.

== Encoder Input ==
There is an input for a pulse encoder on JP5. Pin 3 can be connected to an open collector output of an encoder. Its input resistance is 500 Ohms. The cutoff frequency is 16kHz. E.g. a 60 pulses/rotation encoder can spin up to 18000 rpm before the limit is hit. By changing the value of R2 the cutoff frequency can be varied (lower value, higher frequency).

Alternatively Pin 1 and 3 can be connected to a quadrature encoder found embedded in many motors. It has better response than a single channel.

Additionally Pin 4 can be connected to an index pulse for future use with synchronous motors.

Pin 2 provides 5V with an output resistance of 120 Ohms to power the diode of an optical encoder with 30mA. You can bridge R7 to obtain plain 5V.

== Communication ==
JP6 provides a TTL level (3.3V) UART interface. It can be directly connected to the provided TTLUSB adapter. Pin 1 provides the 3.3V net of the Olimex board. It can be used to power the board or to power an external module like a ZigBee or bluetooth transceiver. 100mA should not be exceeded. Pin 2 is TX, Pin 3 is RX and Pin 4 (next to the inductor) is GND.

The communication parameters are fixed to 115200 8N2 (2 stop bits!).

There is a CAN interface on JP5. Pin 25 is CANL, Pin 26 is CANH

== Power input ==
The main board contains a regulated buck converter to power all of its components. The allowed input voltage is 7-26V.

== Pin Header Summary ==
Pin Header JP5
{| class="wikitable"
|'''Pin'''
|'''Name'''
|-
|1
|Encoder channel B
|-
|2
|30mA output for IR diode
|-
|3
|Encoder channel A or single channel input
|-
|4
|Index pulse input
|-
|5
|Cruise Control Input (12V)
|-
|6
|Throttle Input (0-3.3V)
|-
|7
|Start input (12V)
|-
|8
|Regen Pot Input (0-3.3V)
|-
|9
|Brake Input (12V)
|-
|10
|Brake output (open collector 0.5A)
|-
|11
|Motor Protection Switch (12V, PWM inhibit when low)
|-
|12
|DC contactor output (open collector 1A)
|-
|13
|Forward (12V)
|-
|14
|Error Signal (open collector 0.5A)
|-
|15
|Reverse (12V)
|-
|16
|Over/Under Voltage (open collector 0.5A)
|-
|17
|Emergency Stop (12V, PWM inhibit when low)
|-
|18
|Temperature PWM output (open collector 0.5A)
|-
|19
|BMS Over/Under Voltage input (12V)
|-
|20
|Precharge Output (open collector 0.5A)
|-
|21
|Motor Temperature Input -
|-
|22
|Motor Temperature Input +
|-
|23
|GND
|-
|24
|Vcc (7-26V)
|-
|25
|CANL
|-
|26
|CANH
|}

[[Category:Hardware]]

Main Board Version 3

2019-03-29T03:52:08Z

Dmpitsch: Added v3 images

[[File:main_board_v3.jpg|thumb|Main board]]
[[File:mainboard_pinout_v3.png|thumb|Connections]]
[[File:schematic_main_v3.png|thumb|Schematic]]

The main board is the heart of the inverter system. It contains all the intelligence that is needed to convert the users inputs into motor shaft movement. It also contains all the protection circuitry to avoid damage in case of errornous inputs.

The pdf schematic is available via github.

Its distinct features are:

== Digital inputs ==
There are external 8 digital inputs on JP2. A voltage of >7V is interpreted as a logical 1 (high). They all have a cutoff frequency of 40Hz.
# Cruise Control (Pin 5). This input sets the current motor speed as the set point for cruise control. Cruise control is disabled with the Brake input.
# Start (Pin 7). This input starts the inverter operation.
# Brake input (Pin 9). This input is connected to the brake pedal. It sets a configurable negative torque (regen) which overrides the throttle. I.e. if you press both, brake pedal and throttle, the throttle is ignored.
# Motor Protection switch or emergency stop (Pin 11). This input is connected to the thermal protection switch that is embedded into many motors. Its function is to inhibit the PWM signals when the motor overheats. This input directly controls the PWM signals without software interaction. The PWM is enabled as long as this input is high and shut down as soon as it goes low. If your motor does not have such a switch, tie the input high permanently.
# Forward (Pin 13). If this input is high the motor spins forward.
# Reverse (Pin 15). If this input is high the motor spins backward. When neither input is high the motor will not spin at all.
# Reserved input (Pin 17). This used to be an emergency stop input but I decided to reduce the number of HW stop pins. Emergency stop can now be chained to pin 11.
# BMS input (Pin 19). This input limits the motor torque (both negative and positive) if a BMS signals an over or undervoltage condition. It is active high, i.e. high means over/undervoltage.
There is one more digital inputs on JP3
# Error input (Pin 13) This pin is pulled high (5V). When pulled low an error is signalled and the PWM is inhibited

== Digital outputs ==
There are 5 external open collector outputs on JP2. They sink up to 300mA each, DC contactor output can sink up to 600mA.
# DC contactor output (Pin 12) This output is activated when the bus voltage is above a given threshold and the start pin goes high. It is disabled on overcurrent, motor overheat and emergency stop.
# Error output (Pin 14) This output is activated on over current, motor overheat, emergency stop, throttle out of range.
# Voltage output (Pin 16) This output is activated when the bus voltage surpasses an upper or lower threshold.
# Precharge output (Pin 20) This output is activated when the inverter is powered up. It is disabled as soon as the DC contactor is enabled.
# Brake output (Pin 10) This output is high when potnom reaches a certain negative threshold. The purpose is to switch on the brake light on a certain regen level

== PWM outputs ==
There is one external PWM output on JP2, Pin 18. It outputs a duty cycle that is proportional to the motor or heatsink temperature or speed. Its offset and gain is software configurable. The frequency is fixed to 17kHz. It is an open collector output so it can be used with most temperature gauges in cars. It can sink up to 300mA.

There are 6 internal PWM outputs on JP3. Pins 4, 8 and 12 provide a GND connection, Pins 1, 5 and 9 provide 5V. The outputs are 3.3V, 16mA.
# PWM Top phase 1 (Pin 2)
# PWM Bottom phase 1 (Pin 3)
# PWM Top phase 2 (Pin 6)
# PWM Bottom phase 2 (Pin 7)
# PWM Top phase 3 (Pin 10)
# PWM Bottom phase 3 (Pin 11)
There is a configurable dead time between top and bottom outputs.

== Analog Inputs and over-current protection ==
There are 3 external analog inputs on JP2.
# Throttle input, 0-3.3V (Pin 6). Cutoff frequency 16Hz, input resistance 10k.
# Regen pot input, 0-3.3V (Pin 8). Cutoff frequency 16Hz, input resistance 10k.
# KTY83 temperature sensor input (Pin 22 positive, Pin 21 negative). Cutoff frequency 16Hz
There are 4 internal analog inputs on JP7. Pins 5, 7, 10, 15, 16 provide a GND connection, Pin 1,2, 8, 11, 12 provide stablelized 5V.
# Udc (Pin 4) Bus voltage input. 0-3.3V, cutoff frequency 16Hz
# Il1 (Pin 6) Current phase 1. 0V=-Imax, 1.67V=0A, 3.3V=Imax (software configurable). Cutoff frequency 48kHz.
# Il2 (Pin 9)
# Heatsink temperature (Pin 13), cutoff frequency 16Hz
The two current sensors are used for the programmable hardware over-current protection. A trip limit can be programmed that configures a hardware comparator. When the given current limit is hit, the PWM signals will be shut down without software interaction.

== Position feedback ==
There is an input for a pulse encoder on JP2. Pin 3 can be connected to an open collector output of an encoder. Its input resistance is 500 Ohms. The cutoff frequency is 16kHz. E.g. a 60 pulses/rotation encoder can spin up to 18000 rpm before the limit is hit. By changing the value of R2 the cutoff frequency can be varied (lower value, higher frequency).

Alternatively Pin 1 and 3 can be connected to a quadrature encoder found embedded in many motors. It has better response than a single channel.

Additionally Pin 4 can be connected to an index pulse for future use with synchronous motors.

Pin 2 provides 5V with an output resistance of 120 Ohms to power the diode of an optical encoder with 30mA. You can bridge R7 to obtain plain 5V.

Alternatively Pin 1 and 3 can be connected to a sin/cos feedback device and Pin 4 can generate a resolver excitation sine wave. In that case Pin 2 provides 1.7V to make the resolver feedback unipolar.

== Communication ==
JP1 provides a TTL level (3.3V) UART interface. It can be directly connected to the provided TTLUSB adapter. Pin 1 provides the 3.3V net of the Olimex board. It can be used to power the board or to power an external module like a Wifi or bluetooth transceiver. 400mA should not be exceeded. Pin 1 is 3V3, Pin 2 is GND, Pin 3 is TX, and Pin 4 is RX (Olimex UEXT compatible).

The communication parameters are fixed to 115200 8N2 (2 stop bits!) and may be raised to 921600.

There is a CAN interface on JP5. Pin 25 is CANL, Pin 26 is CANH

== Power input ==
The main board contains a regulated buck converter to power all of its components. The allowed input voltage is 7-26V.

== Pin Header Summary ==
Pin Header JP2
{| class="wikitable"
|'''Pin'''
|'''Name'''
|-
|1
|Encoder channel B/Resolver S3
|-
|2
|30mA output for IR diode/Resolver center point S1S4
|-
|3
|Encoder channel A or single channel input/Resolver S2
|-
|4
|Index pulse input/Resover excitation R1
|-
|5
|Cruise Control Input (12V)
|-
|6
|Throttle Input (0-3.3V)
|-
|7
|Start input (12V)
|-
|8
|Regen Pot Input (0-3.3V)
|-
|9
|Brake Input (12V)
|-
|10
|Brake output (open collector 300mA)
|-
|11
|Motor Protection Switch (12V, PWM inhibit when low)
|-
|12
|DC contactor output (open collector 600mA)
|-
|13
|Forward (12V)
|-
|14
|Error Signal (open collector 300mA)
|-
|15
|Reverse (12V)
|-
|16
|Over/Under Voltage (open collector 300mA)
|-
|17
|Reserved
|-
|18
|Temperature PWM output (open collector 300mA)
|-
|19
|BMS Over/Under Voltage input (12V)
|-
|20
|Precharge Output (open collector 300mA)
|-
|21
|Motor Temperature Input -
|-
|22
|Motor Temperature Input +
|-
|23
|GND
|-
|24
|Vcc (7-26V)
|-
|25
|CANL
|-
|26
|CANH
|}

[[Category:Hardware]]

File:Schematic main v3.png

2019-03-29T03:47:49Z

Dmpitsch:

File:Mainboard pinout v3.png

2019-03-29T03:46:13Z

Dmpitsch:

File:Main board v3.jpg

2019-03-29T03:45:34Z

Dmpitsch:

File:Schematic main v2.png

2019-03-29T03:42:33Z

Dmpitsch:

File:Main board v2.jpg

2019-03-29T03:41:06Z

Dmpitsch:

File:Mainboard connections v2.jpg

2019-03-29T03:40:30Z

Dmpitsch:

Main Board Version 1

2019-03-29T03:30:16Z

Dmpitsch: Added v1 images

[[File:main_board_v1.jpg|thumb|Main board]]
[[File:mainboard_connections_v1.jpg|thumb|Main board]]
[[File:schematic_main_v1.png|thumb|Main board]]

The main board is the heart of the inverter system. It contains all the intelligence that is needed to convert the users inputs into motor shaft movement. It also contains all the protection circuitry to avoid damage in case of errornous inputs.

Its distinct features are:

== Digital inputs ==
There are external 8 digital inputs on JP5. A voltage of >7V is interpreted as a logical 1 (high). They all have a cutoff frequency of 40Hz.
# Cruise Control (Pin 5). This input sets the current motor speed as the set point for cruise control. Cruise control is disabled with the Brake input.
# Start (Pin 7). This input starts the inverter operation.
# Brake input (Pin 9). This input is connected to the brake pedal. It sets a configurable negative torque (regen) which overrides the throttle. I.e. if you press both, brake pedal and throttle, the throttle is ignored.
# Motor Protection switch (Pin 11). This input is connected to the thermal protection switch that is embedded into many motors. Its function is to inhibit the PWM signals when the motor overheats. This input directly controls the PWM signals without software interaction. The PWM is enabled as long as this input is high and shut down as soon as it goes low. If your motor does not have such a switch, tie the input high permanently. Of course you can use this input for any other fault condition, e.g. the error signal of a 3rd party gate driver.
# Forward (Pin 13). If this input is high the motor spins forward.
# Reverse (Pin 15). If this input is high the motor spins backward. When neither input is high the motor will not spin at all.
# Emergency Stop (Pin 17). This input has the same function as the motor protection input. It can be used for an emergency stop button. Tie it high otherwise.
# BMS input (Pin 19). This input limits the motor torque (both negative and positive) if a BMS signals an over or undervoltage condition. It is active high, i.e. high means over/undervoltage.

== Digital outputs ==
There are 4 external open collector outputs on JP5. They sink up to 2A.
# DC contactor output (Pin12) This output is activated when the bus voltage is above a given threshold and the start pin goes high. It is disabled on overcurrent, motor overheat and emergency stop.
# Error output (Pin 14) This output is activated on over current, motor overheat, emergency stop, throttle out of range.
# Voltage output (Pin 16) This output is activated when the bus voltage surpasses an upper or lower threshold.
# Precharge output (Pin 20) This output is activated when the inverter is powered up. It is disabled as soon as the DC contactor is enabled.

== PWM outputs ==
There is one external PWM output on JP5, Pin 18. It outputs a duty cycle that is proportional to the motor temperature. Its offset and gain is software configurable. The frequency is fixed to 17kHz. It is an open collector output so it can be used with most temperature gauges in cars. It can sink up to 100mA.

There are 6 internal PWM outputs on JP3. Pins 4, 8 and 12 provide a GND connection, Pins 1, 5 and 9 provide 5V. The outputs are 3.3V, 16mA.
# PWM Top phase 1 (Pin 2)
# PWM Bottom phase 1 (Pin 3)
# PWM Top phase 2 (Pin 6)
# PWM Bottom phase 2 (Pin 7)
# PWM Top phase 3 (Pin 10)
# PWM Bottom phase 3 (Pin 11)
There is a configurable dead time between top and bottom outputs.

== Analog Inputs and over-current protection ==
There are 3 external analog inputs on JP5. The reference voltages are provided as well (Pin 4) so the inputs are connected to sensors or pots directly.
# Throttle input, 0-3.3V (Pin 6). Cutoff frequency 16Hz, input resistance 47k.
# Regen pot input, 0-3.3V (Pin 8). Cutoff frequency 16Hz, input resistance 47k.
# KTY83 temperature sensor input (Pin 22 positive, Pin 21 negative). Cutoff frequency 16Hz
There are 4 internal analog inputs on JP4. Pins 5,7 and 10 provide a GND connection, Pin 8,11 and 12 provide stablelized 5V.
# Udc (Pin 4) Bus voltage input. 0-3.3V, cutoff frequency 16Hz
# Il1 (Pin 6) Current phase 1. 0V=-Imax, 1.67V=0A, 3.3V=Imax (software configurable). Cutoff frequency 48kHz.
# Il2 (Pin 9)
# Heatsink temperature (Pin 13)
The two current sensors are used for the programmable hardware over-current protection. A trip limit can be programmed that configures a hardware comparator. When the given current limit is hit, the PWM signals will be shut down without software interaction.

== Encoder Input ==
There is an input for a pulse encoder on JP5. Pin 3 can be connected to an open collector output of an encoder. Its input resistance is 500 Ohms. The cutoff frequency is 6kHz. E.g. a 60 pulses/rotation encoder can spin up to 6000 rpm before the limit is hit. By changing the value of R3 the cutoff frequency can be varied (lower value, higher frequency).

Pin 2 provides 3.3V with an output resistance of 75 Ohms to power the diode of an optical encoder with 30mA.

== Communication ==
JP6 provides a TTL level (3.3V) UART interface. It can be directly connected to the provided TTLUSB adapter. Pin 1 provides the 3.3V net of the Olimex board. It can be used to power the board or to power an external module like a ZigBee transceiver. 100mA should not be exceeded. Pin 2 is TX, Pin 3 is RX and Pin 4 (next to the inductor) is GND.

The communication parameters are fixed to 115200 8N2 (2 stop bits!).

== Power input ==
The main board contains a regulated buck converter to power all of its components. The allowed input voltage is 7-26V.

== Pin Header Summary ==
Pin Header JP5
{| class="wikitable"
|'''Pin'''
|'''Name'''
|-
|1
|GND
|-
|2
|30mA output for IR diode
|-
|3
|Encoder input
|-
|4
|3.3V
|-
|5
|Cruise Control Input (12V)
|-
|6
|Throttle Input (0-3.3V)
|-
|7
|Start input (12V)
|-
|8
|Regen Pot Input (0-3.3V)
|-
|9
|Brake Input (12V)
|-
|10
|GND
|-
|11
|Motor Protection Switch (12V, PWM inhibit when low)
|-
|12
|DC contactor output (open collector 3A)
|-
|13
|Forward (12V)
|-
|14
|Error Signal (open collector 3A)
|-
|15
|Reverse (12V)
|-
|16
|Over/Under Voltage (open collector 3A)
|-
|17
|Emergency Stop (12V, PWM inhibit when low)
|-
|18
|Temperature PWM output (open collector 100mA)
|-
|19
|BMS Over/Under Voltage input (12V)
|-
|20
|Precharge Output (open collector 2A)
|-
|21
|Motor Temperature Input -
|-
|22
|Motor Temperature Input +
|-
|23
|GND
|-
|24
|Vcc (7-26V)
|}

File:Schematic main v1.png

2019-03-29T03:20:24Z

Dmpitsch: Dmpitsch uploaded a new version of File:Schematic main v1.png

File:Schematic main v1.png

2019-03-29T03:15:52Z

Dmpitsch: