Investigation of a low-cost grid-connected inverter for small-scale wind turbines based on a constant-current source PM generator

Abstract

This paper describes a novel low-cost grid-connected inverter for small-scale wind turbines based on a high-inductance PM generator operating in a constant-current output mode. The PM generator is connected to a switched-mode rectifier (SMR) which consists of an uncontrolled rectifier and a switch. The combination of the high-inductance generator and uncontrolled rectifier produces a constant DC current. The switch is used to modulate this current and produces an output current whose fundamental component is a full-wave rectified sinewave and is in-phase with the grid voltage. A line-frequency commutated H-bridge inverter and LC output filter is used to produce a sinusoidal output grid current. The concept is verified using simulations and experimental results