Control of a VSC-diode bridge combination for industrial rectifier applications

This paper discusses the suitability of a voltage source converter (VSC)-diode bridge combination as a rectifier in industrial applications. This particular rectifier arrangement consists of a full rated diode bridge rectifier and a partially rated two-level voltage source auxiliary converter. This combination helps achieve power conversion at medium voltage with low voltage switching devices, improve current quality through pulse width modulation (PWM) operation and smoothen the dc-link voltage by transferring the ripples to the dc-side of the auxiliary converter. Moreover, this topology can be extended by replacing the two-level auxiliary converter with a multilevel converter such as diode-clamped three-level converter to achieve higher voltage levels and better power quality requirements. Apart from that, there is a possibility of interfacing energy storage devices through the dc-side of the auxiliary converter to mitigate power fluctuations. Control strategies and modulation techniques that are specific to the topology for different operating scenarios are simulated in MATLAB/Simulink. Simulation results are presented to verify the operation of the proposed topology.