Research On Direct Torque Control For Permanent Magnet Synchronous Motors Drive System Fed By Matrix Converter

Matrix converter(MC) which is regarded as a new type of AC-AC inverter has a multitude of advantages, such as adjustable power factor, no need of energy storage about big inductor and capacitor, small volume, achieving the two-way flow of energy, etc. Therefore, it attracts more and more attention of many scholars both at home and abroad in the power electronics and power transmission industry. With the rapid development of the technology of power electronic device manufacturing, application technology and control theory, the research of matrix converter as emerging AC-AC converter which can replace the traditional AC-AC converter has became mature, and its application occasions have been extended to the motor drive, the motor fault tolerance, aircraft actuator, space power and wind power and other occasions. The era that MC replaced the traditional AC-DC-AC converter has come.Permanent magnet synchronous motor(PMSM) has the advantages of small volume, high efficiency, high power density, simple structure, energy saving, so it has widely used in the important areas of industry, transportation, military, aviation and others. For the PMSM drive system, the two current mature control methods include field oriented control(FOC) and direct torque control(DTC). The inherent current inner loop of FOC affects the drive response performance of the system. In comparison, DTC simplifies the coordinate transformation, and it makes the response of system fast. Thus, this thesis combinates MC and DTC method to make a discussion in depth.The main research content is divided into the following aspects:(1) The basic structure and principle of MC are analyzed. Using MC to replace the traditional AC-DC-AC converter, the PMSM DTC system is designed. The merit of fast response which is possessed by the DTC system is maintained, and the system input side power factor is improved.(2) The PMSM DTC system fed by MC based on the sliding mode controller is designed under the condition of the system load torque and the given speed change. The anti-disturbance capability of the designed system under the variable given speed conditions can be enhanced.(3) In order to achieve a better control effect, in the case of the system load torque and a given speed change, the DTC PMSM system fed by MC based on active disturbance rejection controller is designed. The design of the system based on active disturbance rejection controller has good anti-disturbance capability for the load torque change and the given speed change.The two methods of the designed speed regulators are applied to the DTC PMSM system, which can improve the ability of the system about load anti-disturbance and tracking the change of the given speed. And compared the system based on sliding mode variable structure controller speed regulation with based on active disturbance rejection controller,the latter has better anti-disturbance ability and can avoid the shortcomings of the system chattering in sliding mode control. Finally, simulation results were taken to verify the feasibility and effectiveness of the proposed method.