Power Resistors Based Soft-starter for a Small Grid Connected Induction Generator Based Wind Turbine

Abstract: This paper presents power resistors based soft-starter strategy for a small induction-generator based wind-turbine. Soft-starter is designed to reduce inrush current or surge in current while achieving a proper synchronism between the generator and the grid. The designed soft-starter successfully limits the high inrush current during the connection of the wind-turbine system to the grid. An experimental investigation is done to find out suitable values of the power resistors for soft-connection of a small wind turbine system with the grid. Tests are carried out on a micro-controller controlled small induction generator based wind energy conversion system at the Energy Systems Lab, Memorial University. The test setup consists of a computer controlled DC motor, a three phase induction generator, system instrumentation, a micro-controller based system controller and relays for the system connection/disconnection from the grid. The designed soft-starter limits the initial surge 2.12 times the rated current of the induction generator. Although solid state devices are good candidate as a soft-starter for large wind-turbine system, a low cost power resistors based arrangement described in this paper is very effective and good for small wind turbine systems. This paper describes the soft-starting principle, the designed soft-starter, application of the soft-starter in wind power generation, and experimental test results. For awards Wally Read Best student paper and Best Graduate of the Last Decade Paper IEEE student Member. No:80555718