Compact and Cost-efficient Power Regeneration System for Voltage Source Converters

Abstract:
This paper introduces a compact and cost-efficient circuit for feeding back regenerative power from frequency inverters into the grid. The setup described in this paper has standard European size (160mm x 100mm) and offers 1kW peak power. It can be connected between the DC link of the frequency converters and the mains to control the regenerative power. The circuit essentially consists of a buck converter, a synchronous inverter and a line filter. Thanks to silicon carbide devices in the buck converter, high switching frequencies can be achieved without the disadvantage of high switching losses. As a major advantage compared to active front end converters, the presented power regeneration system can work in parallel to uncontrolled rectifiers. This offers a large market potential even for retrofitting in existing installations. The first section of this paper describes the general operation of the feed back circuit. Then the dimensioning of the buck converter and the synchronous inverter are shown in a detailed way, because its components determine costs and volume. In the last section a practical setup and measurement results are shown.