Sliding mode control for AC signal power amplifier

In this paper, the detailed analysis and design for DC-AC buck inverter with sliding mode control is presented. As the new inverter is composed of two independent current bi-directional buck converters, the sliding mode controller is analyzed by an equivalent circuit. The design of the sliding surface coefficient is analyzed according to its relationship with the dynamic response of the system, the existence of sliding motion and the inductor current during starting-state. The stability of sliding mode controlled buck inverter is researched on system parameters and the frequency of output signal. Furthermore, the switching frequency is calculated for the practical system. Finally the experimental results are presented to support the analysis and to prove that the sliding mode control strategy can achieves a stable, robust, and good dynamic goal. The new inverter can be used in signal amplifier and uninterruptible power supplies (UPS), etc