The Research On The Converter And It's Control Of Direct-Driven Wind Power Generation System

Currently direct-driven wind generation is considered to be an important research direction in wind generationg technology area.In direct-driven wind generation sytem, converter is the only path for the power of the generator feeding to the grid, it is a device which can change variable voltage variable frequency power into constant voltage constant frequency power, it can regulate the current and the power factor rapidly, reduce the harmonic pollution on the grid, it's a key part in the direct driven wind power generation system, it is important for stable and efficient operation of the system, mastering this technology will promote the development of China's wind power industry, and enhance the field of wind power capacity of independent innovation.First of all, the paper introduces the wind power industry's history and current situation, focusing on the direct drive wind power technology, research status,and forecasts the development trend of wind power technology; Secondly, analyse the history and current of the converter technology, select the double PWM topology as the research object of this paper; then introduces the topology, operation principle and control strategy permanent magnet synchronous generator(PMSG) and double PWM topology in detail.On this basis, the generator-side converter uses id=0 policy to control the permanent magnet synchronous generator, the particular method is double-loop control mode, the outer loop of the speed,the inner loop of the current; the grid-side converter using double-loop control mode, the outer loop of voltage, the inner loop of current,then introduce the method of designing system parameters in detial.Based on the the actual situation, built the simulation model of the wind power system in the SIMULINK:the generator-side converter part is discussed in variable wind speed and fixed-pitch area, according to the principles of maximum power point tracking(MPPT), the converter control the motor speed to absorb the maximum power, and convert AC power to DC power; the grid-side converter convert the DC power to AC power and feed to the grid with unity power factor and low THD in steady-state, when the voltage of grid varied, the grid-converter should track the phase of the grid in real time.