What makes VESC DRV Burned?
Some customers might have DRV burned problem, it's not because we sent bad controller or we didn't tested before shipment.
All products has been doubled tested and checked before shipment to make sure the products are good and works normal before shipment.
So below we will tell you some common reasons of DRV burned problem:
V4 use DRV8302 driver chip to be used as MOS driver, this part is most vulnerable component in VESC, in V6 this part has been upgraded to better driver chip, but this problem is hard to avoid, please be careful when use VESC and follow below suggestions.
There's 3 common reasons:
- Motor load weight is too heavy, or has instantaneous stall.
- Motor rotation speed is too fast.
- Brake force is too strong when brake.
- When load weight is too heavy: Driver chip receives control instruction from MCU, adjust motor current direction by output high voltage to let MOS on and off. Therefore, Drive IC need to built-in boost circuit to reach high voltage. If motor load weight is too heavy, then driver chip need to output high voltage so that MOS can on and off, but high voltage is not good for MOS and drive IC, would easy burn drive IC.
Motor rotation speed too fast: Please noted, here means the Electric RPM (ERPM) too high would have the problem.
Electric RPM (ERPM)=Motor Pole Pairs Number x Rotation Speed (RPM). If motor Pole Pairs Number is too high, ERPM would be higher, at this time MCU or driver chip don’t have the ability to solve such high speed and load-weight will be very high, which would cause the driver chip overheat or burned out.
Suggest in BLDC mode set 5-6W ERPM, in FOC mode set 3-4W ERPM.
Stall and brake situation: Motor would stall when hall sequence is wrong, skateboard hit something or motor has things gets inside of the motor.
Both stall and brake will make motor instantaneous stall, rotated mechanical energy covert to electrical energy instantly, which voltage rise high in VESC power supply circuit, and then burn drive IC.
Firmware: If controller firmware is not good, will also make MOS switch controller inaccurately, which will cause driver chip working pressure too high and burned.
Driver chip has to many function: V4 driver chip also has step-down circuit except for boost driver, it can convert power supply voltage to 5V and 3.3V. This function makes the VESC can only accept input voltage lower than 60V, even if slightly brake force, working voltage will be higher than 60V and then burn driver chip. Driver chip also has built in computing function after current sampling, this function also makes the driver chip heat, with different factors that make driver chip heat at the same time, finally it will be burned out because of overheat.
How to avoid these problems?
- Match with suitable power motor, motor power is not the higher the better, if motor power is not suitable with controller, higher power motor brake force is stronger, would easy burn driver chip.
Set correct parameters, especially hall sensor sequence, do not run FOC mode in high pole number motors, and do not use high KV motor.
Slightly brake, if you need to brake strongly, then you must use high discharge rate and BMS with same port of charge and discharge, and add rheostatic brake with voltage protection function.
Use V6 hardware, V6 use DRV8301 driver chip, firmware also has been optimized. It use other independent component to reach the function of 5V/3.3V step-down circuit, reduce heat factors and reduce DRV problem probability.