Single Inductor Dual Buck-Boost Inverter Based on Half-cycle PWM Scheme with Active Clamping Devices

What is it about?

This paper presents a single-phase differential inverter named single-inductor dual buck-boost inverter (SIDBBI) for photovoltaic applications based on an improved half-cycle pulse width modulation (HPWM). A conventional dual buck-boost inverter (CDBBI) is a good option for photovoltaic due to step-up/down ability suitable for varying input ranges. However, large inductor current and corresponding increments of inductor size and device ratings have made it less attractive than other topologies. This paper proposes HPWM scheme with active clamping switches to reduce inductor voltage swing, inductor current and component stresses by eliminating dc output offset. Under the proposed modulation, device stresses in CDBBI can be reduced by zero offset, and there arises a chance to integrate half-utilized inductors, main switches and complementary diodes into one set, which is the proposed SIDBBI. 500 W-prototypes of the proposed inverter and conventional one have been built for verifications. Detailed analysis and experimental results show that SIDBBI with the proposed HPWM has advantages of reduced inverter size by 40.4% than CDBBI with the proposed HPWM, maintaining inverter efficiency over 96% and wide input coverage by step-up/down ability. Comparative analysis show that the proposed SIDBBI is competitive in terms of component counts, stresses, losses and topological issue, compared to various buck-boost inverters.

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