PWM Plus Phase Angle Shift (PPAS) Control Scheme for Combined Multiport DC/DC Converters

Abstract

Multiport dc/dc converters are widely employed in hybrid energy generation systems to provide stable power to key loads with high power density. In this paper, the switch duty cycle and the phase angle of the interleaved converters are employed as two control freedoms to achieve decoupled voltage regulation within a certain operating range among different ports, which is referred to as pulsewidth modulation plus phase angle shift (PPAS) control scheme. An interleaved bidirectional buck-boost converter and a full-bridge converter are integrated together to derive a combined three-port dc/dc converter for photovoltaic (PV)-battery hybrid energy systems, which is adopted as a typical example to explore the clear performance of the proposed PPAS control strategy. The bidirectional buck-boost converter and the full-bridge converter share the same power MOSFETs in the primary side, which simplifies the circuit structure and improves the power density. The duty cycle of the interleaved bidirectional buck-boost converter is adopted to realize the maximum power point tracking and the voltage balance between the battery and the PV cell in the primary side. Furthermore, the phase angle of the interleaved buck-boost converter is employed as another control freedom to achieve accurate secondary output voltage regulation. Finally, a 100-W PV-Battery energy system is designed and tested to verify the effectiveness of the proposed scheme.