Study On Control Strategy Of Permanent Magnet Synchronous Generator PWM Rectification System

As the development of permanent magnet materials in recent years,the permanent magnet synchronous generator with permanent magnet excitation have attracted wide attention due to the merits of its simple mechanical structure,high efficiency and high power density.The rectification system combined with PWM rectifier has high power factor and low harmonic content,and its performance is far better than the structure of traditional diode rectifier and converter.It is widely used in vehicles,new energy power generation and some other industries.Therefore,the research on this system is of great practical significance.This paper focuses on the rotor position angle estimation method of the permanent magnet synchronous generator which used on vehicles and the vector control of the rectifier system based on position sensor.The details are as follows:Firstly,the theory of constant phase amplitude coordinate transformation and the principle of permanent magnet synchronous generator and PWM rectifier are introduced briefly,and the mathematic models of them are established on this basis.Secondly,the principle of vector control of permanent magnet synchronous generator PWM rectification system was analyzed in details.Aiming at the problems of high cost,difficult maintenance and easy disturbance caused by the use of mechanical rotor position sensor in the generator,a sliding mode observer is constructed to estimate the rotor position of the permanent magnet synchronous generator,which is applied to the control of the rectification system.Thirdly,some improvements are proposed to deal with the disadvantages of the traditional sliding mode observer such as large chattering and inaccurate rotor position estimation.The continuous function is used to replace the symbolic function,the adaptive sliding mode gain is used to replace the fixed sliding mode gain with the change of counter potential,and the inverse tangent operation is replaced by the phase-locked loop technique as the estimation method,which inhibits the chattering of sliding mode to some extent and improves the estimation accuracy.Finally,in order to improve the anti-disturbance performance of the rectification system,a fuzzy adaptive PI regulator is designed to replace the classical PI regulator of the outer voltage loop,which effectively improves the recovery ability of the system when disturbed,reduces the overshoot of the output voltage and speeds up the adjustment time.