Modeling and Simulation of Direct-coupled Permanent Magnet Wind Generators System with Maximum Power Point Tracking Control Using Simplorer

摘要

This paper presents a maximum power point tracking (MPPT) method which does not need information like wind turbine characteristic and wind speed. The MPPT method is effective especially when air density of the environment changes. A wind system based on a low-speed direct-coupled permanent generator is constructed in this paper. Firstly, the theoretical principle of the MPPT method is analyzed, which includes two basic steps: wind turbine speed disturbance and output power measurement. Increase the speed disturbance when the output power increases, and decrease the speed disturbance when the output power decreases as well. This method will not be effected by the ageing problem and have better control result. Secondly, the simulation of the wind turbine is proposed, which is based on a DC motor. Wind turbine is a power source whose amplitude changes continuously. Thus the simulation of wind turbine is to describe its characteristics and make equivalent output power. Using a DC motor to model the wind turbine is a practical and feasible method to obtain a better approximation. Thirdly, accounting for the permanent magnet generator and main circuit as well as control scheme, the model of wind generation system was built in Simplorer, which is a useful FEM tool for the applications in motor control, electrical transmission, aerospace industry and power electronic device. Finally, the control system based on TMS320LF2407 was constructed. Voltage and current sampling , IGBT driver, thyristor control, speed detect and snubber circuit are designed respectively. The current, output power and speed are measured at constant wind speed. The experiment of controlling wind turbine speed and output power at constant wind speed on a DSP platform verifies the feasibility of the MPPT method presented in the paper.