STEVAL-IHM023V3 MotorControl Workbench 5.Y.2 ACIM

[Omer Ab]

Hi..

I am trying to drive an ACIM motor on a project with STEVAL-IHM023V3 using Nucleo STM32G431RB MCU, but in some cases when starting the motor, a phase explodes and Rshunt ,IGBT, driver ,(sometimes) Nucleo STM32G431RB are destroyed.

I did some research on this problem and I came across two possibilities;

1- According to the UM1823 documentation, in the Overcurrent protection part, the maximum allowable current of the shunt resistor is 7Arms when the voltage on the CP+ pin of the L6390 gate driver exceeds 0.53 V.

 According to BOM values, Rshunt=0.15 ohm 2W therefore

I shuntmax= (2W/Rsunt)^0.5 =3.651A<7A most likely the reason why Rshunt exploded and L6390 overcurrent protection not activated.

2- I use the following function to start the engine;

MC_ProgramSpeedRampMotor1((int16_t) USER_SPEED_VALUE,0);

MC_StartMotor1();

when user speed=1500rpm

When I apply this, the motor cannot start under load and it draws excessive current and explodes everything..

Can you help with this?

project features:

DCbus=320V

Inominal=5A

current sensing :three shunt resistor

over current topology : external protection

[Gigi]

Ciao Omer

I agree with your analysis of point 1. The maximum current that can be sustained by the shunt resistor is in the range of 3.6A and the overcurrent protection is to high.

Before to try with a bigger power board you can try to evaluate the possibility to put another shunt resistor in parallel to the one that is already present in the board. I see in the schematics that there is the footprints for another shunt.

Maybe putting another 0.15Ohm in parallel for each shunt resistor and changing the setting in the FW using the Workbench (Rshunt = 0.075 as equivalent) in current sensing shunt resistor value (Generate again and recompile the FW). This can sustain a little bit more current before to explode.

Ciao

Gigi