μ-based robust controller design of LCLC resonant inverter for high-frequency power distribution system

High-frequency AC (HFAC) power distribution system (PDS) has recently received more and more attentions and has a broad application from electric vehicle to Micro-grid. The resonant inverter is commonly used to provide the fixed frequency output for point of load (POL). However, the control and implementation of high-frequency resonant inverter is complicated to provide good steady and dynamic performance, because of the worse operating circumstance from parameter uncertainties, inaccuracy model, as well as load and line perturbations. Although H_∞ robust controller has already been widely examined, the feedback voltage controller designed by μ-synthesis accurately provides more effective analysis and design framework to achieve robust stability and robust tracking performance. In this study, the perturbations and control target are analysed to construct the unstructured and structured uncertainties for resonant inverter. A new μ-based controller is designed by μ-synthesis to testify its tracking performance under the given perturbations, and the robust performance of proposed controller is theoretically evaluated by μ-analysis. The prototype of simulation and experiment are implemented with a rated output power of 120 W and operation frequency of 25 kHz. The results prove its superiority over traditional PI and H_∞ controllers for HFAC power source constructed by LCLC resonant inverter.