Improved one-cycle-controlled active rectifiers with high-order input filters

In this paper, a double-edge modulation based one-cycle-control (OCC) scheme is presented for regulation of active rectifier. With minor modifications made in OCC core, the nonlinear carrier formed by integration and reset of dc-link voltage error turns out to be a symmetrical triangle waveform in steady-state, which can effectively eliminate the even order harmonics generated by the conventional OCC in three-phase systems. To cater for high power applications, LCL-filter is subsequently introduced for switching ripple suppression. In this case, it is shown that active rectifiers controlled by the proposed OCC may exhibit significant loss reduction in passive damping mode and much lower total harmonic distortion (THD) of input currents in active damping mode. Furthermore, practical implementation issues like tuning of active damping gain and triplen offset injection in OCC are also discussed in details. All the theoretical findings discovered in this paper are eventually verified by experimental testing on a 1 kW laboratory prototype.