Control of a stand-alone inverter-based distributed generation source for voltage regulation and harmonic compensation

Operation of a distributed-generation (DG) source, producing sinusoidal output voltage and supplying nonlinear loads is characterized by a nonsinusoidal voltage at the point of common coupling (PCC). The situation gets particularly aggravated during the islanding mode, when the grid power is not available. This deteriorates the performance of other loads connected in parallel. A scheme based on nonsinusoidal pulsewidth-modulated control of a stand-alone inverter-based DG source is proposed to regulate and produce a sinusoidal voltage at the PCC. It is demonstrated that without any current sensor or compensating device, the individual harmonic components and THD of the supply voltage at the PCC can be reduced to the desired level. Simulations have been performed to study the viability of the proposed scheme and all of the results are presented.