An Efficient Power Electronic Interface for Multifunction RTPV System Feeding AC/DC Loads in Zero Net Energy Buildings

An efficient power electronic interface suitable for zero net energy building (ZNEB) is proposed. The proposed grid-connected topology is devised to supply both ac and dc loads of ZNEB. The proposed rooftop photovoltaic (PV) system consists of a voltage source converter (VSC) and a dc–dc boost converter. However, the PV is grid-tied through VSC alone, falling under single-stage conversion system (SSCS). Whereas, the boost converter is to supply the dc loads of ZNEB. Two controllers, namely field programmable gate array (FPGA) and a low-cost digital signal controller (DSC), are employed for the proposed system. The control algorithm in FPGA ensures maximum power extraction from PV, even at low irradiance and the DSC maintains a constant voltage at dc load terminals. The proposed system avoids the problem of low-voltage gain at lower irradiance, which is the major drawback of conventional SSCS. And, it provides the flexibility of designing the boost converter for the rated power requirement of dc load, which offers the benefit of operating the boost converter with flat efficiency curve, which is around 95% for all irradiance throughout the day. The performance of the system during steady-state and response of the controllers during transient conditions are presented and validated by comparing the experimental and simulation results.