Control Strategy of PWM Rectifiers Connected to Unbalanced Grids

Abstract

Current-controlled voltage source converters are widely used in grid-connected applications, for example at ac drives with indirect frequency converters. The negative sequence component of the grid voltage causes ripples of the dc voltage in the intermediate circuit. Some sophisticated topologies of current controllers that can cope with grids containing both the positive and negative sequence components are summarized and compared for this purpose. A new dual current control algorithm was developed and tested in the Matlab/Simulink environment.