Second-Order Rotating Sliding Mode Control With Composite Reaching Law for Two Level Single Phase Voltage Source Inverters

Abstract

In the recent past, the integration of distributed generation via power electronic interface like voltage source inverter (VSI) allows attaining the desired voltage quality by adopting appropriate control law. This paper presents sliding mode control (SMC) with composite reaching law technique for regulating output voltage under variable load conditions for single phase VSI. Inherent properties of SMC like robustness are achieved usually at the cost of chattering along the sliding surface. To handle this trade-off, optimal sliding surface selection mechanism is applied with adoptive reaching law based on state variables magnitude to set the value of control gain. The novelty of the proposed technique is related to composite reaching law that overcomes constraints associated with SMC. The proposed reaching law is a combination of exponential, power, and difference function. The intelligent mix of these functions makes the suggested reaching law more effective in achieving a high-speed convergence rate of system states and significant chattering reduction. Moreover, the sliding surface is chosen using a time-varying slope based on error variables. Comparative study of SMC with cosine exponential reaching law (Cos-ERL) results, fractional power rate reaching law (FPRRL) and proposed composite reaching law with rotating sliding surface(C-RL-RSS) applied on single phase voltage source inverter under variable load conditions validates the effectiveness of the proposed C-RL-RSS based SMC. It is revealed that the proposed C-RL-RSS based SMC is proficient in achieving very low %THD in the output voltage along with reduced chattering and minimum tracking time.