About the voltage spike problem of MOS in motor driver

zp6916

About the voltage spike problem of MOS in motor driver [Copy link]

 

The figure shows the VDS and VGS waveforms of the MOS end of the brushless DC motor controller. In addition to a voltage spike at the moment of shutdown, there are two large voltage spikes in the middle. By looking at the VDS of the other two phases, it is found that the voltage spikes here are introduced when other tubes are switched on and off. How to solve this problem?

qwqwqw2088

MOS tube drive, increase the MOS tube G pole driving resistance, if the circuit is reasonable, the spike can be reduced or even disappear.

qwqwqw2088

Also, the test may not be accurate, or you can wrap the oscilloscope probe around a magnetic ring and test it.

1399866558

Circuit problem, fix it.

zp6916

qwqwqw2088 posted on 2019-11-1 16:52 MOS tube drive, increase the MOS tube G pole drive resistance, if the circuit is reasonable, the peak can be reduced or even disappear.

The G-pole resistor can only adjust the front peak, and the two following ones don't seem to have any improvement effect.

zp6916

1399866558 posted on 2019-11-2 21:02 Circuit problem, change.

Circuit problem? Or PCB layout problem?

What's the problem?

qwqwqw2088

qwqwqw2088 posted on 2019-11-1 16:52 MOS tube drive, increase the MOS tube G pole drive resistance, if the circuit is reasonable, the peak can be reduced or even disappear.

First identify the problem

Is it the circuit, PCB, or MOS driver?

What is the drive structure?

motordriver

Add CBB capacitors between the busbar and the ground to absorb the damage. Add one to each bridge arm.

zp6916

motordriver posted on 2020-3-2 16:44 Add CBB capacitors between the busbar and the ground, one for each bridge arm

Adding capacitors is effective, but it loses some efficiency. In addition, since the chip MOS tube is used, the distance between VCC and GND is too far, and CBB is not easy to add.

nian1206

Give a thumbs up, the poster is really a good person for sharing his information so completely.

nian1206

Give a thumbs up, the poster is really a good person for sharing his information so completely.

Ming8686

1. Can increase the driving resistance

2. Add an RC filter between DS

3. Test problem, the test can be done by twisting the two wires and using an isolated power supply

lkh747566933

The gate increases resistance and capacitance to slow down the MOS switching speed. An RC filter circuit is added between DS

mutouzhebie

There is cross-talk between UVW, and capacitors are added between DS. The capacitance value will vary due to circuit and PCB distribution parameters. It is actually verified and dynamically adjusted until the power consumption is acceptable.

小新333

1. Can increase the driving resistance

2. Add an RC filter between DS

3. Test problem, the test can be done by twisting the two wires and using an isolated power supply

lkh747566933

Adding a driving resistor at the gate of the MOS tube can slow down the opening and closing time of the MOS. Another method is to directly connect a small resistor and capacitor in series with the DS to absorb this spike.

XMXKSD

I have a brushless motor driver board that needs programming. I need help for a fee.

lkh747566933

Connect a small resistor and capacitor in series at the upper bridge arm GS end to see if it works.