I thought maybe there is something wrong with the motor, so today I tested with a Motenergy ME1304 axial flux PMSM which I had available "off-the-shelf". This motor has a sincos position feedback and the V3 mainboard read the position feedback just fine.
To my big dissapointment the behavior is completely the same! The motor just make a rough click and over current fault is asserted.
I am also still experiencing a strange behavior every time I apply power to the V3 mainboard. After applying power, the stored occurlim value is -100.
If I try to start the inverter at this point even without any voltage applied on the DC-link, occurlim fault is asserted.
If I first set occurlim to over -1000, say -1100, the inverter start normally into manual mode. After this one successful entering into manual mode, I can set the occurlim back to -100 and it starts in manual mode just fine. The same happens with sin FW.
What could explain this behavior? Is it possible that something on the V3 mainboard is damaged? Remember, all the PWM channels, current inputs and position feedback is tested to work...
With the ME1304 connected to the inverter, I measured the phase outputs. The first oscilloscope capture shows the phase1 in blue and phase2 in yellow. The second picture shows phase1 in blue with phase3 in yellow.
According to the captures, Phase1 and 3 are in phase and both connected to DC-link(+) while phase2 is in 180 degree phase shift and driven to DC-link(-).
I had a light bulb in series, so this is why the voltage is only at 10V level after the starting pulses.