Small signal modeling, analysis and control of naturally clamped soft-switching current-fed three-phase Bidirectional DC/DC converter

A small signal analysis and a closed loop control design of naturally commutated current-fed three-phase isolated dc/dc converter are presented in this paper. State-space averaging technique is used to derive the small signal model. Based on the derived small signal model, a closed two-loop controller is designed and implemented on mixed signal (analog and digital) processor Cypress PSoC 5. A complete design procedure is presented. Simulation results using PSIM 9.0.4 and experimental waveforms from a 750W prototype with the designed controller are illustrated to verify the stability of the control system. Experimental results for step changes in load clearly show satisfactory transient performance of the converter and validate closed two-loop design.