Over Current SW Fault with HSO [High Sensitivity Observer (Sensorless)]

[riteshEDC]

Hi,

Currently I am evaluating HSO [High Sensitivity Observer (Sensorless)] in our custom Inverter board () with B-MOTOR-PMSMA1 motor. But when I start the motor it jerks and giving Over Current SW Fault. 

Our custom board has following key components.

1. Infineon 6ED2230S12TXUMA1 gate driver
2. MCS1806GS-3-30-Z Current sensor 

 

The same inverter board with B-MOTOR-PMSMA1 motor is working for Observer + PLL configuration. 

I suspect that this board is having current sensor with ± 37.5 A measurement range designed for higher wattage motor giving fluctuation/slow response for  B-MOTOR-PMSMA1 motor with 2.8A current rating.

Please help me to identify root cause of update project configuration to make it run with B-MOTOR-PMSMA1.

Attached following items for your reference.

1. W30_SLIM_EVKMotor_HSO.stwb6 [MC Workbench config file]
2. W30_SLIM_305_3IC_v4.json [HSO Inverter Board Designed File]
3. W30_SLIM_305_3IC_v2.json [PLL Inverter Board Designer File]
4. W30_SLIM_EVKMotor_PLL.stwb6 [PLL MC Workbench Config File]

Our end goal is to run Higher watt motor with our custom board. But first we need to understand HSO before and its tuning with smaller motor. 

 

[Gael A]

Hello riteshEDC,

Have you tried using the RsDC start-up method instead of the PolPulse to see if the alignment is done correctly and the motor starts ? If it starts with RsDC, then it means the PolPulse is badly tuned.

If it doesn't start, then you could try enabling the Open Loop mode and start checking that your currents are correctly sampled and read by the HSO

[riteshEDC]

@Gael A ,

Thanks for your reply.

I have already tested the motor using RsDC mode, and I’m observing the same “Over Current SW” error. The only difference is that in RsDC mode, the motor rotates for a few turns before the error appears, whereas in PolPulse mode the error occurs immediately.

However, I noticed that when I run RsDC, the tool automatically reduces the Current Control Kp from 1.92000 to 0.087. With this reduced Kp value, the motor is now able to rotate for more turns even in PolPulse mode.

 

I also tried running in Open Loop mode, testing various values of current-control Kp and omega_i. The motor does run—sometimes faster or slower depending on the tuning—but after some time it still triggers the “Over Current SW” error.

I am not very experienced with Open Loop current control PID tuning, especially for HSO. Could you provide some tuning guidelines that are specific to HSO so that I can at least run the motor reliably in open loop?

Regarding hardware: I’m using multiple ADC units (ADC1, ADC2) for U, V, and W current sensing. The STMC designer warns that all three phase‑current channels should ideally come from the same ADC. Could this be contributing to the issue, especially in HSO mode?

For PLL-based control the same board works fine, likely because only two phase currents—both from the same ADC block—are used.

 

[Gael A]

Hello riteshEDC,

Have you profiled your motor using the Motor Profiler feature ? We usually keep the current PID gains deduced from the Profiling step. If your motor starts turning, it might be interesting to tinker with the speed PID gains instead.

As of open loop, I advise to first use it to check that the target current is equal to the measured current, and in the correct direction. I can also see that the software overcurrent limit is set to 3.34A in the Workbench (Speed Sensing Config. tab), is this intended ?

[riteshEDC]

Hi @Gael A ,

No, I didn't profiled the motor. As currently i am using R57BLB50L2 motor B-MOTOR-PMSMA1 which motor provide by ST. So i thought it's parameter are already tunned. 

 

And i tried enabling Motor Profiler in HSO config but seems like Motor profiler not working with HSO config.

But with Motor Profile turned On, motor keeps jerking. and stays in RUN state without giving any error.

And Soft Over Current Limit has been auto calculated. 

I tried increasing to 5A, 7A. But still getting the same over current sw fault and i can observe that current is reaching to |5| A limit. 

As you suggested, I don't find target current in plot available parameter list.

 

I captured Id and Iq. 

Kp = 0.087

Kp = 0.0087

 

 

 

[riteshEDC]

I tried running in open loop current mode as per your steps, but getting the same "Over Current SW" error.

And in your previous reply you suggested to do Motor Profile, But at that time I tried using "Profiler.qml" GUI that's why got error "This Profiler doesn't supports HSO".
But today i realize that in HSO GUI qml also there is Option for Profiler. I tried to run that but getting "ERROR_DC_AC". May be due to LS and RsAC seems negative.