Issues with PAC5524 and BLDC (3kW) Motor Control in Lithium-Ion Battery Applications

Power Solutions Intelligent Motor Controllers
1

I am developing a dedicated motor controller for the BLDC HPM3000B Model Motor (3kW with 48V) based on the PAC5524 IC. I am using Lithium Ion battery (around 57V fully charged).

My tests started with the evaluation board; however, upon the first trial of running the motor with the appropriate setup and GUI connection interface, the BLDC motor didn’t start, and the PAC5524 IC was short-circuited in several integral pins alongside the high-side MOSFETs.

I designed my controller similar to the EVK, and the first peripheral test worked fine, including communication interfaces, theoretical PWM signals, and good ADC readings. However, in the first trial of running the HPM3000B BLDC motor, right after the command “ON 6 step Trapezoidal” was pressed, the buck configuration stopped working, with the VP and VHM pins short-circuited, turning off the entire system, similar to what happened with the EVK. The only short-circuit component in my controller is the PAC5524, so I assume that some abs rating was abused when trying to start the motor (my guess would be the VP pin).

Unfortunately, I only saw the following comment in the forum after the controller was developed: The best choice for my application initially would be the PAC5532 IC. However, I would like to understand which ABS rating is being initially abused, when and how the Abs Max of the PAC5524 is abused, and if there are changes that I can make to make the operation of the motor selected with the controller design possible.

“One last note. The most I would ever recommend a PAC5523 to be operated at on battery based applications is 48V, assuming leaded acid batteries. If you are using Lithium Ion battery chemistries, and the nominal voltage is more like 50V to 56V, I definitely think you should only consider PAC5x32 devices as it would be very hard to ensure the PAC5523’s Abs Max is not abused.”

I would like to ask if there are more people who have encountered this problem and if there is any information that could be shared regarding the issue I am having. Thanks in advance.

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Moreover, I was able to test a new scenario with the same controller developed but with a new PCB (new board, new components). In this scenario, I tried to run a 24V motor with a stable nominal voltage of around 36V. The motor didn’t start running; however, in these conditions, the ratings of the PAC5524 were not abused at first sight. However, while testing the firmware, the buck regulator stopped working, with the DRM pin now working at a 10kH switching frequency with a 1% duty cycle. This low value of the duty cycle only gives enough time for the inductor to charge less than 1V, not supplying the rest of the system, including the PAC5524.

It seems that no component or pin of the PAC5524 is short-circuited. Any information regarding similar issues is useful as I am trying to resolve them and explain why they are happening.