A Simplified Power Loss Model of LLC Converter with Accurate Voltage Conversion
摘要
The loss estimation accuracy decreases as the switching frequency deviating from the resonant frequency. A DC equivalent impedance model is proposed to improve the accuracy loss estimation, in this paper. The time domain model of LLC is simplified to calculate the average loss of each branches in a switching period, where the DC equivalent impedance can be obtained by circuit manipulation. Then, the equivalent loss model is established, respect to switching frequency, which estimates the loss accurately and describe the relationship between frequency and output voltage succinctly. Through the experiment of a 140W LLC prototype, the error of power loss is basically less than 10%.