Sampled‐data adaptive nonlinear control of shunt power filters

Abstract

AbstractThis study is on the control of shunt power filters associated with nonlinear loads. Specifically, The focus is made on single‐phase half‐bridge filters and the aim is to design a controller meeting two requirements: (1) the effect of current harmonics and reactive power is compensated for so that a power factor close to unity is achieved at the point of common coupling (PCC); (2) the inverter DC bus voltage is satisfactorily regulated. To meet these requirements, we propose a (two‐loop) cascade adaptive controller that is designed on the basis of the system nonlinear model, using Lyapunov stability tools. Compared to existing controllers, the present controller has three major features. It is adaptive compensating for parameter uncertainty. It is output feedback in the sense that it involves an observer estimating online the inaccessible signals. It is sampled‐data and so is immediately implementable using digital means. In addition to theoretical analysis, the performances of the proposed controller are evaluated by simulation using MATLAB/Simulink.