Use of multi layer ceramic (MLC) capacitors in high power converters

A high-ripple current high-voltage multi-layer ceramic (MLC) capacitor was investigated for use in a HF high-power converter application. The MLC capacitor was utilized in lieu of conventional metallized film snubber capacitors, due to its superior low equivalent series inductance (ESL) per /spl mu/f value attribute. Also, the RMS current rating per capacitor volume ratio is high, because the MLC may be operated with a 125/spl deg/C surface temperature rise. However, the present MLC design tradeoff is the higher initial cost per /spl mu/f. This paper characterizes the MLC capacitor equivalent series components, determines maximum allowable RMS current based on thermal constraints and gives a design example of the MLC capacitor used as a split and distributed resonant capacitor in a high power 200 kVA RDCL soft switching GTO power converter.