Research On Digital Drive System Of Permanent Magnet Synchronous Motor

With the development of motor manufacture technology, power electronics technology, micro-processor technology and modern control technology, permanent magnet AC servo system has developed to a high level and has been applied broadly in modern industry manufactures. Nowadays, most of the AC servo systems used in China are imported from other countries. This situation restricts the development of Chinese robot, digital-control and factory automatic equipment.Firstly, on the basis of analyzing the PMSM mathematical model, three current control methods of PMSM vector control are discussed in details, and made a comparison of their characteristics respectively. Then the equivalence of a fast space vector pulse width modulation method and classical SVPWM is proved.Secondly, the design of practical circuit is recommend, including control system based on TMS320F2812 and drive system based on SKHI22A,then the differences of different driver circuits of IGBT is analyzed and compared. Finally the id=0 control method of the vector control system based on the fast space vector pulse width modulation method is selected and designed.Thirdly, a practical method to calculate losses of the IGBT used in the driver system is presented, and the influence of temperature to the losses is taken into account. The heat resistance equivalent circuit of the dissipation system is analyzed and the calculation formulas of the temperature of the dissipation system are derived. The temperature variety of IGBT's carapace is analyzed theoretically, and the experiment is done.Finally, the problem of dead-time compensation in AC servo system is presented. The Error voltage vector of the inverter caused by dead-time effects is analyzed by the average value method. On the basis of analyzing and deriving of two familiar dead-time compensation methods, a novel method of dead-time compensation based on position measuration is proposed, the experimental results verify that this method has a good compensation effects. Then an on-line method of dead-time compensation based on Time delay control observer is proposed by MATLAB/Simulink, the simulation of the system is carried out, and the simulational results verify the availability of the method.