| With the rapid development of permanent magnet materials,PMSM has many advantages,such as high power density,simple structure,high efficiency and good stability.The excellent performance of sine wave permanent magnet synchronous motor has made its application range more and more widely.Conventional permanent magnet synchronous motor control methods include magnetic field orientation control and direct torque control.Direct torque control with respect to the field oriented control system has simple structure,small degree of dependence on motor parameters,torque and speed response is fast,but the conventional direct torque control uses two hysteresis comparators to control the stator flux and torque.,and because of the use of voltage space vector discrete and limited to the flux and torque adjustment,will inevitably increase the torque ripple.Aiming at the shortcomings of traditional direct torque control,improved direct torque control technology is developed,such as direct torque control based on twelve vectors,torque predictive control and direct torque control based on space vector modulation.Although the former two parts reduce the torque ripple to a certain extent,and improve the current and flux linkage waveform,the effect is not very obvious,and the switching frequency is not fixed.The latter solves the defects of the fixed voltage vector in DTC is limited in fundamentally,while the fixed switching frequency at a certain frequency,can reduce the torque ripple in a certain extent,in view of the above two conditions,this paper proposes a permanent magnet synchronous motor direct torque diode clamped three level space vector modulation based on the control technology,we call the three level SVM-DTC technology.This paper will focus on permanent magnet synchronous motor(PMSM)direct torque control technology based on three level space vector modulation.Finally,but also improved the calculation method of the original system and the amplitude of stator flux vector angle,using the model considering voltage reconstruction technology based on current direction of dead three level inverter,the new system improved more easily by the microprocessor and hardware resources to achieve.Then,the application of PLECS software to build simulation model,and the use of three level NPC inverter experimental platform,analyzes the simulation and experiment,verified the improved SVM-DTC system under no-load or load,high speed or low speed condition has good performance,torque,flux and current with ideal waveform. |
