A single-stage single-phase bi-directional grid interface circuit with digital lookup table based control

Emerging load-side commercial and residential building technologies are driving the need for high performance, low cost line-interface systems. This paper reports on the design and test of a single-stage single-phase bi-directional line interface circuit and controller that provides high quality AC line waveforms along with load-line regulation of the DC bus. The circuit is based on a series-parallel connected interleaved flyback topology, with a single integrated coupled magnetic device. A digital controller relies on a lookup table based approach, which utilizes either on-line training or pre-training of the controller so that the internal current waveform loop is effectively run open-loop within a given half-line cycle.