Hello everyone!
I'm trying to design a high power h-bridge.
The DC voltage is 200V and the motor is rated for 20A.
This is a servo motor (brushed) with an encoder.
I have written a program for the MCU that uses the encoder and PID for position control.
Now i need to design a proper H-bridge.
I have some 150A 1200V brick IGBTs and IR21844 drivers. I made some tests with only the drivers connected to the gates of the bricks and scopes seem fine.. I don't want to blow up the bricks so I was thinking if the IR21844 are the right drivers. They hava only one input for driving the HIGH side and LOW side IGBT.
So if I am running the motor 50% duty in one direction 50% of the time the motor is driven and 50 is braking?
Is this going to work or will I be producing huge current spikes?
I better like the idea of using IR2110. Those drivers have seperate inputs for high side and low side so I could drive only one IGBT.
Thank you!

 

Using the IR21844 you can take the /SD input low to turn off both high and low side.

 

Yes i was thinking about the SD pin... It shuld be in phase with input when i want do drive the HIGH side IGBT and if i want to go in the other direction i would release th SD pin and drive the input LOW. That way the LOW side IGBT is active... that could work but i think its easyer to buy IR2110.
Plus this is a servo motor i need to brake it with the IGBTs when it reaches zero position. I need to PWM brake the motor if I just turn both IGBTs on i would create a huge current spike. The motor has alot on interia.
Any advice on braking?

 

Where are the IR21844 usefull? Clearley not for motor control?

 

As with others I agree that for what you are wanting to do you should be using driver IC's that give you full control over each switching device independently.

It's the only way you will get proper PWM controlled speed and dynamic braking effects with your motor.

 

what do you think about this design? please ignore the markings of the IGBTs and Diodes.... I just made a quick sketch of the design.
A,B and C are possibilities when controlling the motor

 

This schematic is intended to be used with IR2110 and 10ohm Gate resistors and 1k Pull-down resistors betweern the gates and sources. For the current sensing i was thinking of using a low pass filter of 1 Kohm and 22uF so that thsignal is filtered at 7Hz. And a 3V zener diode for protecting the DAC of the MCU

 

Can someone help me determine the snubbers?
Thank you!

 

Why do you need snubbers as well as diodes? I would have thought that the diodes are sufficient to the task.

 

Ok so i will eliminate the snubbers. Thank you!