Other Parts Discussed in Thread: DRV8301
I am using the DRV8301 board connected to a BLDC motor with a maximum current limit of 100 amp. I am running a sample rate of 45 kHz decimated to 15 kHz. It is an 11 pole pair motor and I am driving it using Lab 5b and Lab 10a. I am not using field weakening. The motor has a 258 kv rating and we are using it up to 6000 rpm. The motor was characterized in Lab 2 and has the following setup.
#elif (USER_MOTOR == NeuMotor250V2)
#define USER_MOTOR_TYPE MOTOR_Type_Pm
#define USER_MOTOR_NUM_POLE_PAIRS (11)
#define USER_MOTOR_Rr (NULL)
#define USER_MOTOR_Rs (0.0146962907)
#define USER_MOTOR_Ls_d (1.03721777e-05)
#define USER_MOTOR_Ls_q (1.03721777e-05)
#define USER_MOTOR_RATED_FLUX (0.00887547713)
#define USER_MOTOR_MAGNETIZING_CURRENT (NULL)
#define USER_MOTOR_RES_EST_CURRENT (5.0)
#define USER_MOTOR_IND_EST_CURRENT (-5.0)
#define USER_MOTOR_MAX_CURRENT (60.0)
#define USER_MOTOR_FLUX_EST_FREQ_Hz (80.0)
Kp_spd = 3.0
Ki_spd = 0.039999
Kp_idq = 0.04336339285
Ki_idq = 0.0944596529
The motor starts and runs well under no load and medium load conditions. I increase the loading until the source motor current (a battery of 28 volts) is approximately 18 amps. It slows a bit from the 6000 rpm but still does well. If I try to increase the load it reaches a point that the motor starts a high pitched squeal and the current will not increase. It seems from what the documents say that it should continue to increase current flow but something seems to be stopping it. The battery is capable of 55 amps continuous (verified) so it does not seem to be the issue. The DRV8301 should run to 60 amps so that does not seem to be the limit.
Can someone give me a clue where to look to determine the bottleneck please.