Design of Dual-Buck Inverter Control System Based on Posicast Control

Considering oscillation problem of the controlled second order systems, the improved control method called Posicast is pointed out and adopted to solve the object control problems, such as spring system and power converter circuit system. Firstly, the low frequency and large amplitude resonant peak of the conventional second order inverter system is analyzed, and the Posicast control unit is adopted in the output current control loop to weaken the resonant peak effect. And then, classical PI and repetitive control strategy is introduced to keep the aimed output state tracking in the power frequency signal and the low periodic disturbance signal. The small signal analysis, modeling and transfer function of dual buck circuit inverter is pointed out, and the output voltage and current feedback signal in double loop control method with PI controller is applied. The inner current control loop operates by hysteresis strategy, which has the advantages of easy implementation, reliability and fast response speed in the different load condition. The outer voltage control loop aims to keep output voltage in the good sinusoidal and steady-state characteristics in different load condition. Besides, the introduction of multi-resonant control method also obtains the good output characteristics of the system significantly improved, compared with the classical PI method of using feed-forward current control loop to weaken the load resistance effect to disturbance, and the cost of the inverter is lower. Simulation and experiment verify the feasibility of the system control scheme, and the circuit control system has obtained better output waveform quality, faster dynamic response, accurate voltage regulation accuracy and high efficiency.