MCF8329A: Regarding the problem when starting motor rotation

Hi Higa,

Please allow me some time to look into this. I will aim to get back with you by Wednesday of next week.

Regards,

Joshua

Joshua-san

Do you have any update?

Best regards,

Higa

Hi Higa,

1. Based on the register settings and the FG output, I believe that the algorithm is getting past the handoff correctly. Could you tell me what the algorithm state is when the fault occurs, I want to make sure that the device is getting into closed loop?

2. I recommend trying to lower the CL_ACC (closed loop acceleration) and CL_DEC down to 40 from 500. If using this speed lowers the number of ABN_SPEED Faults you can then try increasing the value of CL_ACC in small increments.

3. I noticed that the open loop acceleration being used is much lower when compared to the closed loop acceleration, is there a reason for using the selected open loop acceleration?

Regards,

Joshua

Hi Joshua-san

Thank you for your reply.

1. -> Let me confirm to my customer.

2. ->Even if I reduce CL_DEC, ABN_Fault still occurs.

3. ->This is because if they increase the open loop acceleration, an error will occur before entering the closed loop and the control will stop.

Best regards,

Higa

Hi Daisuke,

Can LOCK1_EN be set to Disable to see if the motor runs into any other faults or if it is able to spin successfully with the ABN_SPEED fault disabled?

I noticed that the value programmed into BASE_CURRENT is set for ~15A. What is the value of sense resistor is being used on the board?

Daisuke Higa said:

2. ->Even if I reduce CL_DEC, ABN_Fault still occurs.

Just to make sure, lowering CL_ACC's value down to 40 was also reduced?

Regards,

Joshua

Hi Joshua-san

The value of sense resister is 10mohm.(CSA_GAIN=10V/V)

>Just to make sure, lowering CL_ACC's value down to 40 was also reduced?

Decreasing the value of CL_ACC to below 40 made no difference.

On the other hand, a customer reported that the ABN_SPEED error no longer occurred after reducing the speed input (reducing the PWM duty), so they

responded by lowering the speed input to an acceptable level.

However, when it transitions to a closed loop and enters constant speed rotation, it suddenly reverses rotation.

RVS_DR_EN is set to 0b (disabled).

I attach the each waveform data as below.

Suddenly, the rotation is reversed from closed-loop control. Immediately before starting reverse rotation, the load increases.

Do you know how to avoid it? (It is desirable that this can be avoided through settings.)

Best regards,

Higa

Hi Joshua-san

My customer tried changing the settings, but it didn't improve.
Is there anything else to try?

Best regards,

Higa

Hello Higa-san,

Please allow me some time to look into this. I will get back with you by Thursday.

Regards,

Joshua

Hi Joshua-san

Do you have any update?

Regards,

Higa

Hi Daisuke,

Could you provide a zoomed in capture of the OUT signals and phase current when the motor changes direction? We went to see if the commutation is switching and causing the reverse rotation.

Regards,

Joshua

Joshua-san

Thank you for your reply.

I'll let me request to my customer.

If possible, could you please let me know what you think is the cause?

Regards,

Higa

Hi Higa,

At the moment I believe that the open to closed loop handoff settings are causing most of the issues. With the information you have provided so far, I cannot determine why the motor is spinning in reverse after the handoff.

For adjustments that can be made to to fix the handoff period, can the CL_SLOW_ACC be reduced to 20 Hz/s? Please keep the THETA_ERROR_RAMP_RATE at 0.2 deg/ms and the CL_ACC at 40 Hz/s from the changes suggested before when testing the CL_SLOW_ACC change.

I would also recommend adjusting the ILIMIT, LOCK_ILIMIT and HW_LOCK_ILIMIT to be closer the the motors rates peak current. I would recommend setting HW_LOCK_ILIMIT to 60% and LOCK_ILIMIT to 60%, this will set LOCK_ILIMIT and HW_LOCK_ILIMIT to 9, and 50% for ILIMIT to set the current limit to 7.5A. 

Regards,

Joshua