Research On Pmsm Control System Based On Indirect Matrix Converter

Matrix converter (MC) is a novel AC-AC power converter which has the advantage of sinusoidal input and output currents, unity power factor, bidirectional energy transmission and absence of large DC link storage elements. Indirect matrix converter (IMC) is a new matrix converter developed in resent years. Because it is composed of relatively independent rectifier stage and inverter stage, the structure of indirect matrix converter is simple compared to conventional matrix converter and could be modulated using matured control strategies for rectifier stage and inverter stage. Permanent magnet synchronous motor (PMSM) is a commonly used server motor which has simple structure, high reliability and power density. The speed is exactly proportional to input current frequency. PMSM is widely used in aerospace, national defense, robot, CNC machine tools and so on. In this thesis, IMC is employed in PMSM servo system and the closed-loop control system based on IMC is researched, making the advantages of IMC and PMSM combined, which is promising in servo system.Firstly, the background of this issue is introduced, including the invention, development, advantages and applications of MC. State of the art for MC-based PMSM servo system is also introduced, depicting the objective and significance of this issue. Secondly, the rectifier stage and inverter stage of IMC are modulated separately. Using matured techniques in traditional power converters, PWM control strategy is employed for the rectifier stage of IMC and SVPWM control strategy is employed for the inverter stage of IMC to fulfill the modulation for IMC, by which AC-AC power conversion is carried out.Then, the PMSM closed-loop servo control system based on IMC and vector control technique is designed, including speed servo system and position servo system. The command speed and command position is tracked by this system. The feedback loops in this closed-loop system contain current loop, speed loop and position loop. Traditionally, current loop and speed loop are regulated by PI controller and position loop is modulated by P controller. Given some disadvantages in above system, the control algorithms of closed-loop system are improved based on fuzzy control theory. A composite controller is used in speed servo system and fuzzy P controller is used in position servo system. A comparison of the performances (including speed, electromagnetic torque, stator currents, rotor angle position, etc) is made between improved and traditional servo system.Lastly, because the existence of speed and position sensors makes the system large in volume, costly and limited in the applications in harsh environment, speed estimation method based on model reference adaptive system (MRAS) is applied in IMC-fed PMSM servo control system and speed sensorless control is realized.