Study Of Voltage Control On Speed Sensorless Marine Permanent Magnet Shaft Generator

In marine power systems,shaft generator is an important energy-saving emission reduction device.It is not only conducive to environmental protection,but contributes to saving shipping costs.Marine shaft generator piston using permanent magnet synchronous generator(PMSG),with high magnetic flux density,no excitation winding and slip rings,simple structure,reliable operation,high efficiency and advantages for low speed,is an important direction of shaft generator researching and applying.PMSG under variable loads and speed will output changing voltage and frequency.This paper proposes a dual PWM rectifier-inverter system as the electric energy conversion device.Frequency control is easy in this system,so this paper is focusing on DC-side voltage control strategy.This paper introduces the structure and characteristics of PMSG,studies various voltage rectifier control methods,and then utilizes an unity power factor output voltage control method of rectifier side.We establish mathematical model of salient-pole PMSG and studies the speed range of the generator.Based on the establish of PWM rectifier mathematical model,the double closed-loop decoupling control strategy is submitted.To overcome the inherent defects of the mechanical speed and position sensors,sensorless shaft generator speed and rotor position identification methods have been studied.MRAS method is proposed for real-time speed and rotor position estimation in vector control methods.MATLAB simulation on rectifier control strategy is carried out.Output characteristics of rectifier under variable loads and speeds is studied.To achieve shaft generator's AC side voltage and frequency stability,analysis and simulation on the inverter side' control strategy is carried out.Output characteristics of inverter side are analysed.Then,unity simulation is carried out based on achievements above.The results indicate that under fixed speed and load changing ranges the shaft generator could output AC power contents the ship power gird.Finally,the automatic code generation of the rectifier side control system based on Simulink model using F28335 DSP is achieved.