Research On Constant Voltage Control System Of Permanent Magnetic Synchronous Generator During Wide Speed

Due to the features of high power density,simple control,small volume and light weight,Permanent Magnet Synchronous Generator has great application in areas such as the DC power system of electric vehicle.This thesis was based on the topology of PWM rectifier.Aimed at the request of constant DC output voltage during wide speed and high power quality,this thesis mainly studied several parts as shown below:First,the thesis proposed the improved flux weakening control with the improved Space Vector Pulse Width Modulation overmodulation strategy and single current regulaorbased on vector control.The method can make most of the PWM rectifier’s voltage use ratio,enlarge the speed range.The method had low copper loss and avoids the problem of the coupling of two current regulators,which can improve the dynamic property.The improved overmodulation strategy incorporated two modesof theovermodulation in single mode,which avoided the complex calculation compared with traditional overmodulation strategy.Then the thesis explained the disadvantages of fixed d–axis voltage and variable d–axis voltagebased on single current regulator.On account of the disadvantages,the flux weakening control of variable d-axis voltage based on optimized current trajectory was proposed,which can reduce the copper loss and promote the voltage use ratio effectively.Then,aimed at the harmonic introduced by the overmodulation strategy and took the delay introduced by digital control into account,this thesis proposed the quasi-resonant controller with the function of phase compensation.The proposed quasi-resonant controller was discretized by using impulse invariance.As a result,the discretized controller has a lot of trigonometric functions.This thesis improvedthe discretized method,which can simplified the program effectively.Finally,this thesis used MATLAB/Simulink to build simulation model.The overmodulation strategy,the flux weankening control based on single current regulation and the quasi-resonant controller with the function of phase compensation were simulated and verified based on the simulation model.Then design the hardware and software of the system,build the experiment platform and debug the platform.The experiment results verified the validity of the above oretical analysis,which established the foundation of further study on constant voltage control of PMSG.