Design and analysis of an energy recycling electronic load system

An energy recycling electronic load system with multiple input channels for DC power supply burn-in test is proposed. It has high efficiency and good performance. The theoretical analysis and the control strategy are presented in this paper. The proposed system employs Input-Parallel and Output-Series Interleaved ZVS Flyback-Forward (IPOS-IZFF) converters with active-clamp circuits as the front-end stage, which can step up the low voltage of DUTs (Device Under Testing) to a high dc-bus voltage efficiently. A 3-phase 4-wire (3P4W) grid-connected inverter with neutral line current control is used as the back-end stage, which can feed the energy back to the utility grid. An improved repetitive controller is applied to achieve high quality of feedback power. A 15-kW prototype has been built and tested to verify the theoretical analysis.