Three-Phase PWM AC-AC Buck Converter Small-signal Modeling, Dynamic Analysis and Control System Design

Based on three-phase PWM ac/ac buck converter feeding general R-L load, carried out a valid method for its small-signal modeling. An equivalent circuit which is simple but contains all the key dynamical information of the original three-phase ac/ac converter was deduced by high/low-frequency reactance division and complex DQ transformation; Exact small-signal model was built-up and then found that the open-loop converter with inductive load approximately is a second order oscillating system and is critical stable; An effective compensator with good stability and fast dynamic response was brought forward, and the close-loop control system achieved a good performance.