Cascaded Control of High-Frequency Bidirectional Multi-Phase Boost Converters Implemented on Low-Cost FPGA

Abstract:
This paper addresses model-based cascaded control of multi-phase bidirectional boost converters operating at high switching frequencies. The model-based control is executed clock-synchronously to the switching frequency, resulting in high-bandwidth control dynamics that allow to minimize passive components and thus converter size. To achieve the required tremendous calculation effort for the control algorithm within one switching period, the control algorithms are implemented on an inexpensive Spartan-6 FPGA. It is demonstrated how pipelining can be used to maximize the FPGA’s throughput and to keep the logic footprint small via resource sharing among all dc-dc converter phases. Experimental results of a 42 kW 3-phase bidirectional SiC boost converter operated at 150 kHz are presented to demonstrate the performance of the control algorithm.