Design On The Dual-PWM Converter Of Permanent Magnet Synchronous Generators For Wind Turbines

In recent years, the development of wind power is significant and gradually become a new important branch of energy utilization. At present, Wind power generation mainly uses the doubly fed induction generators (DFIG) or mulitievel direct dirve permanent magnet synchronous generators (PMSG). Permanent magnet synchronous generators for wind turbines system includes permanent magnet generator and full power converter as the core. The converter has the function of maximun power point tracking, power factor regulation and active power, reacive power decoupling control function. The system has the function of gault isolation because the gird side and generator is separate. Power failure will not result in damage to the converter. The converter also has a storage capacity of active power and reactive power, to ensure that the system plays a a supporting role in the no wind or less wind conditions. In the same condions, PMSG capacity are much higher than those of DFIG capacity, particularly suitable for small wind power generation system.This paper analyzes the working principle of dual PWM converter, respectively on the machine side and gird side, to establish the mathematical model of PWM rectifier and PMSG in the two phase synchronous rotationg coordinates. The PWM rectifier is based on voltage vector oriented Iq=0, unit power factor control. The machine side uses the rotor field oriented Id=0control and maximum power point tracking (MPPT) control. According to the theoretical analysis, using Matlab/Simulink modeling and simulating dual PWM converter system. Establishment of a model has guidance for follow-up research of control strategy, speed sensorless control and power tracking.In this paper, a speed sensorless control method of permanent magnet synchronous generator is researched. The sliding mode observer is designed based on the extended electromotive force. The observer can be used accurately for embedded PSMG. According to the operation condition of permanent magnet synchronous generators for wind turbines, the switching method of the sliding mode observer for rotor position estimation is proposed. The method has guidance for permanent magnet synchronous generators switching.The control block diagram is established based on permanent magnet synchronous motor. Reduction and approximation is used to simplify the structure of control system. Permanent magnet synchronous generators parameters are got by parameter identification. On this basis,current loop and speed loop PI regulators are designed. The machine side current loop is set to type I system, the speed loop is set to type II system. It provides guidance for auto-tuning method.Finally, this paper expounds the design of control system with DSP and CPLD as the core, the main circuit design based on IPM as the core, and the software design of the system. System experiment was done based on Software and hardware platform.