LCL filter for three phase active front end

Thread Starter

borisxyz

Joined Apr 21, 2011
2
Hello,

I have a question about LCL filter for active front end. I was wondering what the advangate is connecting capacitors in such a filter in Y configuration instead of delta. It seems I cannot find a reason why Y connection is better than delta. Connecting caps in delta results in smaller current through the caps. Also, delta configuration will reduce the amount of capacitance by a factor of 3 compared to Y.

On the other hand, some manufacturers seem prefer to use Y connection instead of delta. Can someone explain? Thanks
 

Thread Starter

borisxyz

Joined Apr 21, 2011
2
designnut:

Active front end is also known as active rectifier. Typically, it has 6 IGBTs controlled by PWM and dc bus cap. The main idea behind is to generate constant dc bus voltage from three phase ac voltage. LCL is what inserted between active rectifier and three phase power supply to attenuate PWM harmonics so that proper voltage and current THD levels are obtained.
 
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