Fully Symmetrical Hybrid PV Converter With Low Common-Mode Noise

Abstract

Hybrid converters with multiports (simultaneous DC and AC outputs) are promising solutions to reduce conversion stages from solar energy to various loads, and thereby increasing the utilization of residential PV systems. Considering common-mode noises suppression and high reliability, this paper proposes a fully symmetrical hybrid PV converter concept with two DC ports and one AC port. The proposed converter adopts symmetrical boost impedances at the low-voltage DC port and symmetrical synchronization rectifier switches at the high-voltage DC port. In addition, a symmetrical AC-decoupling inverter, i.e., highly efficient and reliable inverter concept (HERIC), operates as either a boost switch or an inverter to perform DC-DC and DC-AC conversions simultaneously. Combined with a dedicated modulation method with deadtime, the proposed converter has low leakage currents for grid-connected PV applications, low CM noise as a DC-DC converter, and flexible power control capability. Experiments have been carried out on a prototype to verify the effectiveness of the proposed converter.