Design of Residential Photovoltaic Power Generation Systems for Low-Carbon Buildings

Decarbonising residential buildings is a combination of energy demand reduction on the demand side and renewable electricity generation on the supply side. In Shanghai, rooftop photovoltaic (PV) generation could be a viable option to reduce household electric power consumption for detached residential buildings, provided PV array sizing, design of power conversion, grid-filtering and control strategy are tailored. In this paper a preliminary electrical design of a grid connected PV power generation system is based on the low carbon residential building to provide the annual electricity balance is developed. Given a winter design demand of 17.8 kWh/day, an effective sunshine duration of 3.8 h/day and a system-loss coefficient of 1.8, the PV capacity is found to be 8.43 kW. A 10.08 kWp array is selected for use, which consists of 24 mono-crystalline silicon modules, and an estimated module area of 48.0m2. The design is also specified by the direct current (DC) bus voltage of 400 V, the frequency of the DC-DC boost converter of 10 kHz, the frequency of the single-phase sinusoidal pulse-width modulation (SPWM) inverter of 20 kHz, and an inductor-capacitor-inductor (LCL) grid filter. A hybrid constant-voltage and perturb-and-observe maximum power point tracking (MPPT) strategy is employed to enhance the PV operating point tracking under the condition of irradiance change. The simulation results reveal that the hybrid MPPT controller is able to track the new MPP following an irradiance drop from 1200 W/m2 to 600 W/m2 at t=0.8 s. Capacitor current feedback active damping for the LCL filter suppresses the resonance peak and the grid current total harmonic distortion is less than the design limit of 5.00% at 2.45%. These results are helpful for electrical feasibility of the proposed grid connected residential PV system.