A Hybrid Grid and Photovoltaic Dual‐Input Battery Charger

ABSTRACT

This paper proposes a dual‐input battery charger (DIBC) with grid power and solar energy. The proposed DIBC consists of a boost‐type power factor correction (PFC) circuit, a high step‐down DC converter (HSDDC), and a buck switch. The grid charges the battery through the boost‐type PFC circuit combined with the HSDDC, while the solar module charges the battery via the buck switch integrated with part of the HSDDC. To simplify the power circuit of DIBC, the boost‐type PFC circuit and the HSDDC share a common power switch. Additionally, the buck switch shares components of the HSDDC to implement a buck DC converter. The PFC circuit operates in discontinuous conduction mode. To reduce harmonic distortion in the AC input current, the power switches of the HSDDC are modulated using a pair of signals consisting of a DC component and a second‐order harmonic component. Furthermore, the second‐order harmonic components of the two modulation signals are out of phase to reduce the ripple in the DC output voltage. The control of the buck switch incorporates maximum power point tracking to maximise the output power of the solar module. A 200 W hardware prototype is implemented to verify the performance of the proposed DIBC.