Part Number: DRV8301-69M-KIT
Other Parts Discussed in Thread: DRV8301
Hi,
We have big issues with one of our developed pcb:s.
The issues are with identifying a smaller hobby motor (or any motor). We can run Lab2c, but after identifying the motor successfully(it spins up and sets all values) we cannot run it. It jumps violently and just shuts down, indicating that the measured values are off. Sometimes the DRV8301 also indicates a Fault.
We went back and tested with the dev.-kit with the exact same laboration and motor/psu, with no problems. We can identify the motor and run it ok. The values measured with the dev.-kit varies from those measured with our OEM board. Our OEM-pcb is based on the exact same schematic and components, but we have changed the mosfets to IRFH7004TRPBF because of limited space.
The different values measured and our settings in user.h are below, not an enourmous difference;
OEM PCB
gMotorVars.Rs_Ohm: 0.05133501
gMotorVars.Lsd_H: 9.089566e-06
gMotorVars.Lsq_H: 9.089566e-06
gMotorVars.Flux_Vp_Hz: 0.005068441
DEV.-Kit
gMotorVars.Rs_Ohm: 0.07621007
gMotorVars.Lsd_H: 1.472187e-05
gMotorVars.Lsq_H: 1.472187e-05
gMotorVars.Flux_Vp_Hz: 0.004967535
user.h
#define USER_IQ_FULL_SCALE_VOLTAGE_V (24.0)
#define USER_PWM_FREQ_kHz (15.0)
#define USER_MOTOR_TYPE MOTOR_Type_Pm
#define USER_MOTOR_NUM_POLE_PAIRS (6)
#define USER_MOTOR_Rr (NULL)
#define USER_MOTOR_Rs (0.019)
#define USER_MOTOR_Ls_d (1.466606e-06)
#define USER_MOTOR_Ls_q (1.466606e-06)
#define USER_MOTOR_RATED_FLUX (0.005025501)
#define USER_MOTOR_MAGNETIZING_CURRENT (NULL)
#define USER_MOTOR_RES_EST_CURRENT (1.0)
#define USER_MOTOR_IND_EST_CURRENT (-1.0)
#define USER_MOTOR_MAX_CURRENT (10.0)
#define USER_MOTOR_FLUX_EST_FREQ_Hz (1.0)
So here we are stranded now. I can verify that it seems to me that the FET:s at our OEM pcb seems to be switching a bit harder than the ones at the Dev.-kit. Might be because of the lower on resistance in ours. We are using the same gate resistance of 1Ohm, like your dev-board.
Do you have any suggestions on how to proceed with this?
Any tip on where/how can we measure to find out what could be wrong?
Will it be any use trying to increase gate resistance?
Any help right now would be hugely appreciated. We have been working on this PCB for half a year.
Best regards,
Mikael
