Backstepping control for active power filter with LCL filter

Active power filters are widely applied in power system to deal with distorted currents caused by nonlinear loads. As the active power filter (APF) with LCL filter is a serious nonlinear system, conventional control methods cannot have satisfactory performances. A nonlinear control method, backstepping control for active power filter with LCL filter is proposed in the paper. The control adopts backstepping method to design feedback control law based on the state space average model of APF. While introducing virtual control and forming Lyapunov function step by step, the nonlinear controller with global asymptotic stability is obtained at last. Compared with conventional local linearization methods, backstepping method does not ignore any high order nonlinear terms and maintain global system nonlinearity. Thus the proposed control method achieves better control effects such as suppressing LCL resonance without additional passive or active damping. Finally, simulation in MATLAB and experimental results on a 20kVA prototype verify the feasibility and stability of proposed control method.