Transformer-less Single-phase Inverter Based on SPWM Technique for Standalone PV Application

Abstract

In standalone photovoltaic (PV) inverter a total cost and harmonic content are most two
problems that should be satisfied. In general, the main problems of square and modified sine wave inverters
are a higher harmonic content and present the low frequency (LF) or higher frequency (HF) transformer in
its configuration. For this reason, this paper presents a single-phase transformer-less inverter for standalone
PV application. A robust unipolar Sinusoidal Pulse Width Modulation (SPWM) control technique is
presented to control the inverter switches and obtained a sinusoidal output current and voltage. The proposed
inverter is incorporated with the boost converter to provide a high DC voltage level and maximum power
point tracking (MPPT) technique from the PV system. The low cost perturb and observe (P&O) MPPT
technique is used. The performance of the proposed inverter is evaluated using Physical Security
Information Management (PSIM) software. Also, the proposed inverter has been capable to generate pure
sin wave of voltage and current during all conditions, when it runs in variations of weather conditions or the
load variations. Finally, a well THD content in output current waveform is achieved at different solar
irradiation.