Research On PMSM's Fully Digital Control In System Of ISG

Permanent Magnet Synchronous Motor(PMSM) is provided with simpler and firmer structure,lower cost,higher fault tolerant,energy density and operation temperature,higher torque during low speed etc.It has become widely used in the field of Starter/Generator(S/G) system for aviation and automobile.In the project,the electromechanical energy transformation part is the exterior-gibbose PMSM.With developments of power converters and microprocessors,fully digital implementation is the major development trend,and it is excellently flexible to implement new control strategies without ameliorating system hardware.Firstly,the thesis introduces the structure,application information of ISG for automobile and the basic theory of PMSM.Secondly,the thesis introduces the background,development and future prospect of servo system,and mathematical model of PMSM is presented.Thirdly,this paper discusses four current control methods of PMSM vector control carefully and designs ISG control system.It suggests that the rotor field orientation vector control of i_d=0 can be chosen. Then,the methods of digital current control are illuminated,and SVPWM modulation is discussed thoroughly.Mathematical models of position loop,speed loop and current loop of fully digital control system are given,based on all above mentioned,the control performance is analyzed.Methods of initial rotor position detection for PMSM using incremental encoder OIH-35-2500 are discussed.The implementation of M/T velocity detection based on DSP is cited. and a new method of velocity detection is introduced to improve the detection accuracy,the power driver system based on IPM and the interface circuit applying to PMSM have been designed according to the strategy,the software system based on the main chip TMS320F2812 of TI company for PMSM has been designed.In this paper,owning the rated output power and torque of motor are all smaller comparably. we do some relevant experiments,record the current waveform and position in condition of no-load in this thesis has tested the static and dynamic performance,high accuracy.