Research On Novel Vector Control Technology Of Six-Phase Induction Motor

Compared with the three-phase speed regulating system,the multi-phase speed regulating system has the advantages of high power density,high reliability,strong fault-tolerant operation ability,stable torque performance and high power output under low voltage.Therefore,it has broad application prospect in the area of major equipment,such as energy and power,transportation,high-end manufacturing,national defense and military industry.This article will take a six-phase induction motor as the research object and study the new vector control technology of the six-phase motor system.The main achievements are as follows:Firstly,the advantages and disadvantages of multi-phase regulating system are introduced.Overseas and domestic research status of multi-phase regulating system are described.The basic control methods of multi-phase motors are briefly summarized,and the typical several vector control systems of multi-phase motors are described in detail.Secondly,mathematical model of the six-phase induction motor based on the natural coordinate system is deduced.Starting from the space vector decoupling transformation theory,the decoupling transformation matrix is used to decouple the complex motor model with strong coupling in the natural coordinate system,and the six-phase induction motor based on space vector decoupling is modeled and simulated accordingly.The simulation results show the accuracy of the motor model.Then,the SVPWM algorithm and traditional vector control of six-phase induction motor are analyzed.For the traditional two-vector SVPWM algorithm and the maximum adjacent four-vector SVPWM algorithm,there is a problem that the stator harmonic currents are large.By introducing a new virtual voltage balancing vector,the stator harmonic currents are effectively suppressed.On this basis,the vector control technology of rotor flux-oriented control of six-phase induction motor is introduced and the system simulation model under the control of PI algorithm is established.The simulation results show that the system based on PI regulator can effectively adjust the motor speed and flux linkage and achieve the purpose of tracking control.However,this control algorithm is based on the steady-state model of the system,hence it is difficult to make the system obtain superior dynamic and static performance,strong antijamming capability and fast dynamic response.Finally,in order to improve the dynamic and static performance of the system and achieve fast tracking control of motor speed,flux linkage and torque,a combination with backstepping algorithm and vector control is proposed for the six-phase induction motor control system.According to the design method of the backstepping algorithm,the backstepping control system of the closed-loop tracking of the speed and flux linkage and the backstepping control system of the closed-loop tracking of the speed,the flux linkage and torque were designed respectively.The corresponding control system model was built and verified by simulation.The simulation results show that the control system based on backstepping algorithm can obtain superior dynamic and static performance.Because there are external disturbances and internal parameter changes in the actual motor system,in order to further improve the robustness of the system,a control method combining the sliding-mode control algorithm with the backstepping algorithm is proposed.According to its design method,the sliding-mode backstepping controller for the closed-loop tracking of the speed,torque and flux linkage is designed and simulated.The simulation results show that the sliding-mode backstepping control algorithm can maintain the system's good dynamic and static performance,and it can also improve the robustness of the system.