State Plane Trajectory Control of a Soft Switching AC-Link DC-DC Converter

This work presents the mathematical analysis and controller operation of the AC-link dc-dc converter, a parallel resonant converter, for which state plane trajectory control (SPTC) is proposed. The contribution is a simple, autonomous control technique achieving the benefits of bidirectional power flow, soft switching, and converter switching at its natural resonant frequency as opposed to conventional forced control operations. The switching sequence is implemented using an autonomous state machine triggered by the voltage and current state variables of the resonant LC tank, transitioning between modes of operation strategically to achieve said benefits. All results were simulated in MATLAB/Simulink utilizing the PLECS blockset.