Study On Power Conversion Technology Of High Speed Permanent Magnet Generator Based On DSP

The thesis is a part of the project-"The distributed high speed generator system driven by micro-turbines and its energy conversion system",which is supported by the National Natural Science Foundation of China.The high speed generator,for its small volume,high efficiency and great power density,is one of the great concerns in electrical machines.The output of high speed generator is high-frequency AC voltage,which is needed to convert to the constant AC voltage for users through the power electronics power conversion devices. The power supply of high speed electrical machine is high-frequency voltage and the loss of electrical machine density is great and heat dissipation is difficult.In this thesis, three-phase high power factor rectifier is used on high speed generator output side. Three-phase four-leg inverter is used in the inverter link to improve the adaptability of the system because loads in distributed generator are uncertain.In this thesis,three-phase high power factor rectifier and three-phase four-leg inverter are thoroughly investigated.The main contents are listed as follows:First,the three-phase high power rectifier and four-leg inverter mathematical models are in the static coordinate.It is not easy to achieve without static error regulation in the time region because currents and voltages are AC sine volume.The model in synchronous coordinate is set up through the coordinate transformation and decoupled,which is in favor of regulator closed-loop control.On this basis,the controller parameters based on pole-assignment is utilized to design the parameters of control system.A novel control scheme with PD output voltage instantaneous-value feedback inner loop for voltage PID is proposed for four-leg inverter:the inner loop is designed to improve dynamic performance and the voltage external loop can ensure stable performance.The design of the method can achieve dual-loop control and only the output voltage needs to be sampled,which has characters of single-loop and dual-loop and excellence dynamic,static and robust performances. Then,the theory and implementation of two-dimensional(2-D) and three-dimensional (3-D) space vector modulation are given detailed introduction and the simulation analysis of rectifier and inverter is respectively introduced.The simulation analysis of the rectifier verify that three-phase high power factor rectifier can promise stabilization of DC and make output and input current sine to achieve the purpose of power factor correction and realize active inverter so that the DC voltage invert to AC voltage to drag the generator as a motor to start the entire unit in the unit start.The simulation analysis of the inverter verify four-leg inverter has strong capacity to suppress three-phase unbalance and nonlinear loads,so the inverter still is able to output high-quality symmetrical three-phase voltage in the serious asymmetry and nonlinear load conditions and also show the correctness of the scheme with PD output voltage instantaneous-value feedback inner loop for voltage PID.At last,experimental platform is designed and built based on TMS320LF2407A,which is programmed in assemble language.Experimental results verify that the theoretical and simulation analysis is correct.