The Sliding Mode Control Technique For Power Electronic Converter

Nowadays the linear control approach has been widely used in power electronic system. But the controller cannot ensure stability under large variations of system condition changes. The system is unable to produce better performances for wide-range load changes and input voltage variation. Recently, the sliding mode control (SMC) has wide application range in the research of power electronics system, complying with the non-linear nature of switch-mode power supplies. Compared with the traditional control modes, the advantages it brings are its high robustness, good dynamic response, simple control implementation and wide-range signal stability.In this paper, the detailed analysis and design for sliding mode control scheme of power electronic system is presented. The SMC has been implemented on Buck converter, Buck voltage source inverter and full bridge inverter. The hitting and existence condition, sliding surface coefficient of sliding mode control are analyzed in detail to describe the starting and steady state. The sliding mode domain and equivalent control method are used to analyze the dynamic response process and steady range. The output signal frequency of system, ESR, starting process, the delay time, DCM state and steady-state errors are also researched for the implementation in practice system. Further more, the SMC based on reference triangular wave controller (SMC-RTW) is presented to obtain a constant switching frequency and remain the advantages of traditional SMC. The basic frame and operation of SMC-RTW control strategy is introduced. The design and choosing of coefficients are analyzed in Buck converter and Buck voltage source inverter.Finally, the experimental results validate the new control method and analysis in the paper.