Backstepping sliding mode current control for three phase voltage source rectifier under unbalanced input voltage conditions

Abstract

In this paper, a backstepping and sliding mode control-based (BSMC) current control scheme, including both the current control strategy and the control law for three-phase voltage source rectifier (VSR) under unbalanced input voltage conditions is proposed. This scheme takes advantage of the robustness nature of SMC and the systematic design procedure of backstepping, so that satisfactory performance and system robustness can be obtained at the same time. A dual current control structure is adopted to regulate the positive and negative sequence currents in their respective synchronous reference frames. A current control strategy with negative sequence current compensation is adopted to eliminate dc link voltage ripples and ensure sinusoidal ac current. Through instantaneous power flow analysis, relative current references for VSR under unbalanced input voltage conditions are derived. Theoretical analysis is performed and proofs are provided where necessary. Extensive simulation studies are conducted to verify the effectiveness of the proposed BSMC current control scheme.