ST7MFC application immunity motor power stage dicturbance

[jermakov]

Posted on January 02, 2009 at 18:27

ST7MFC application immunity motor power stage dicturbance

[muratterzi]

Posted on May 17, 2011 at 10:14

Because of your motor sounds as strange ,this means pwm pulse frequency apllied to motor is not compatible with your motor or has high noisy adds. You must change pwm freqs. if you hear high freq sounds also produced harmonics can disturb your power stage. are you using optocoupler when driving highside drivers. i offer you fairchild semiconductor fan7888 to drive mosfets together with optocoupler.

[jermakov]

Posted on May 17, 2011 at 10:14

Hello,

I need for experienced advices how to improve BLDC motor controlling application immunity to the disturbance going from the power stage.

I am projecting a software for the e-bike (based on the MCU ST7FMC2S4, rototype of AK-ST7FMC ref board, and application BLDC_3PH_SR_2.0 ), where MCU and motor power stage are placed on the same board and are powered from the same power supply. As result I have a lot of noise from the motor, which disturbances the MCU normal working and causes frequent application crashes.

I extremally need to make the software more stable and protected from crashes.

One of the possible solution is to activate WDT. Sure, I've done this. But I need to say, that this is not 100% solution.

Anyway the system goes frequently crashed.

My system is a bit more complicated and includes one more contorl unit, which communicates with the maqin unit thorugh the SCI interface. All the command (motor start and stop, speed value etc) are generating by control unit exactly.

So when the system gets crashed I can specify three possible crash scenarios:

1. Motor fault state, while main unit reports to the control unit the motor hardware failure. At this state the start of motor gets blocked and the only way to escape - power off and on commands from control unit. By this way the motor state gets restored to idle status.

Problem: - no automatical escape from this state after some timeout.

2. While try to start motor, the WDT generates reset, the motor shortly tries to start with strange sound and nothing more.

Problem: - no automatical current state restoring or motor state reinitiation on WDT reset.

3. Communication gets lost, the application keep working in the main loop but doesn't accept any SCI commands from control unit. The only escape available - by manual reset.

Problem: - WDT doesn't help at such case, the reason of this state occuring still not cleared.

Any advice is welcome very much!

Thank you,

Alexander.