Photovoltaic-battery hybrid power supply applied with advanced-time-sharing switching technique and discrete ripple correlation control

Abstract

Maximum power point tracking (MPPT) is usually desirable in photovoltaic (PV) power applications. The scenario of load demand in excess of power capability that a PV device can provide requires a hybrid power supply (HPS) to employ additional power sources (e.g. AC-line supply or battery power system) for maintaining output voltage regulation (OVR) and MPPT. Such a HPS, in this study, is topologized with a double-input buck conversion circuit which is proven to possess higher efficiency, less component count, lower cost and simpler manipulation, comparing with those conventional parallel-connected single-input single-output converters. Advanced-timesharing switching (ATSS) scheme for PWM switching function generation is developed and utilized to implement smooth and accurate adjustment to output power produced by power sources, without losing OVR, MPPT, and single-input equivalent circuit analysis convenience. Discrete ripple correlation control is selected to realize MPPT. This paper brings forward the theoretical and mathematical interpretation to the aforementioned procedures as well as the simulation-level verification and performance testing.