Exact Analysis of Parallel Resonant DC-DC Converter using Phase Shift Modulation

In this paper, the exact analysis of the Parallel Resonant (PR) DC-DC converter using constant frequency phase shift modulation is presented. Variable frequency modulation for control of resonant converters has some challenges in implementation like EMI filter design, switch driver design etc.. Hence, fixed frequency Phase Shift Modulation (PSM) is preferred in control of parallel resonant DC-DC converter. However, the analysis of PR converter using PSM is carried out using Fundamental harmonic approximation that ignores harmonics and results in erroneous estimation. In order to improve the accuracy and to quantify the intermediate converter parameters, an exact analysis of the PR converter using fixed frequency PSM is discussed. The analysis is important in design and control of the converter. Expression for converter gain and other parameters of interest are derived. Accuracy of the analysis is verified through simulation and experiment of a 1. 5kW prototype.