Hak99
Newbie level 3
Hello, i Have a full-bridge to drive a dc motor. the problem i have is that during a Current level change, i can notice oscillation with frequency in range of 50-100 HZ in the load current (switching frequency is 40KHz).
i guess the reason is the resonance between the Load inductance (12mH) and the bulk capacitor(3mF)
which makes the resonance frequency equal to 1/2pi*sqrt(L.c).
i don't want to use resistors because it makes powerless. also in series with capacitor doesn't suit because it makes the time constant high which is not suitable for other loads connected to the same power supply.
is there any way except having extra resistors to prevent or damp these oscillations? i have read about lossless snubbers but i don't know exactly how can implement them in my full-bridge circuit.
i would appreciate any new ideas. thanks.
here is a schematics of what i have :
i guess the reason is the resonance between the Load inductance (12mH) and the bulk capacitor(3mF)
which makes the resonance frequency equal to 1/2pi*sqrt(L.c).
i don't want to use resistors because it makes powerless. also in series with capacitor doesn't suit because it makes the time constant high which is not suitable for other loads connected to the same power supply.
is there any way except having extra resistors to prevent or damp these oscillations? i have read about lossless snubbers but i don't know exactly how can implement them in my full-bridge circuit.
i would appreciate any new ideas. thanks.
here is a schematics of what i have :