The burned chip in the picture is DRV8302, which is used for MOSFET drive. This chip is the most vulnerable component of VESC, accounting for 80% of the VESC failure rate. VESC6 firmware has been improved but still cannot be avoided 100%.
This phenomenon is caused by the following reasons:
- The load of the motor is too high, or the rotor is blocked instantly.
- The motor speed is too fast.
- The skateboard brake is too strong.
- When the load is too heavy: The driver chip receives the MCU control command, outputs a high voltage to drive the MOSFETto perform the switching action, and adjusts the current direction in the motor. Therefore, the driver IC’s built-in boost circuit will generate higher If the motor load is too heavy, the generated voltage is very high to allow the MOS to switch. The excessive voltage is a danger to the MOS and the driver IC itself. The VESC MOSFET can afford higher voltage than driver chip, so the driver chip collapses first.
- Whenthe motor speed is too fast: It is not that the motor speed is necessarily risky, but the electric speed is the risk. Electrical speed = motor pole pairs × actual speed. If the number of motors and pole pairs is too high, the electrical speed will be correspondingly higher. At this time, the high-speed processing capability of the MCU or driver chip cannot keep up, which will also cause the driver chip to be overloaded and burned due to heat. Generally recommended in BLDC mode, electrical speed 5-6w ERPM, FOC mode 3-4w. ERPM.
- Stalling and braking conditions: Hall phase sequence error, sliding board hitting obstacles, motor entering foreign objects, etc., will cause the motor to stall. Stalling and braking will cause the motor to stop instantaneously, and the rotating mechanical energy is instantly converted into electrical energy by the motor, resulting in a large increase in the voltage in the VESC power circuit. Burn out the fragile driver IC.
- Firmware factor: Inadequate consideration of ESC firmware will also make the MOS switch control inaccurate, resulting in excessive pressure on the driver chip, then burned.
- The driver chip itself has too many functions: In addition to the boost drive, the V4 driver chip also has a buck circuit to convert the power supply voltage to 5V and 3.3V. The maximum input voltage allowed by this function is 60V. If you brake a little, the voltage will be higher than 60V and the entire driver chip will be burned. In addition, if the power consumption of a 5V voltage receiver such as a receiver consumes a lot of power, the driver chip will also heat up. The driver chip also has built-in calculation function after current sampling. This function will also heat up. Various heat effects are superimposed, and the final temperature is too high and burned.
- use a appropriate power motor to each VESC. It’s not “the bigger the better”, and the bigger the motor, the harder it is to brake, and it is easy to cause problems.
Check link of " how to choose suitable ESC for your motor?"
- The parameter setting is correct, especially the Hall phase sequence. Do not use FOC mode on high pole number motors. And the motor KV should not be too high.
Check link of " Motor Detection in VESC_TOOL Step by Step Guide "
- Soft brake. If you want to brake hard, you must use a high discharge rate battery and the same port BMS. Then add the voltage protection type braking resistor.
- Use VESC6 based ESC instead. The VESC6 solution uses DRV8301; the firmware is also optimized; and the 5V/3.3V step-down and current sampling conversion functions are implemented with other independent components in function, reducing heat generation. So the chance of this kind of error in the VESC6 scheme will be small, but it can't be avoided.
Here are VESC6 based controllers in our store: