Research On Low Noise Direct Torque Control For Six-phases PMSM

As we all known, the PWM technology is widely used in variable frequency speedregulation system, which makes the power switch device turned on and off in a determinedway.So the output voltage of inverter contains a large number of harmonic components,which enhances the vibration of the motor, and produces a intolerable electromagneticnoise at the same time. Through the changing of the current harmonic amplitude,using thedirect troque control technology to control the six phases permanent magnetic synchronousmotor. The thesis major research content is as follows:Firstly, the developed and application status of the dircet troque control has beensumed up, Summarized the basic principle of direct torque control technology and itsclassification, introduced the direct torque control of using hysteresis comparison controlmethod, meanwhile, finished the hysteresis comparison space voltage vector selection tablefor six phases permanent magnetic synchronous motor.Secondly, the permanent magnetic synchronous motor control system model based onmatlab simulation software has been built and respectively stimulated the vector controlevolve from the SPWM and direct torque control based on space voltage vector. Thenanalysed the simulation results, verified the direct torque control strategy in the aspect ofreducing the current harmonic amplitude is better than SVPWM through the simulaiton.Finally, according to the torque pulsation problem of the direct torque control. Bassedon the design principle of hysteresis comparison control and the effects of voltage vector,respectively propoed the direct torque control of Space voltage vector table based on theprinciples of torque fastest response denoted by FT-DTC(Fast Torque Control) and thedirect torque control of space voltage vector table based on principles of torque fluxresponse equilibrium denoted as PT-DTC(Poise Torque-Direct Torque Control). Andsimulated the two vector table systems. The simulation results indicated the PT-DTCOptimized the system torque ripple, reduced the current harmonic amplitude.So as toachieve the aim of reducing vibration noise.