| Permanent magnet synchronous motor (PMSM) have good performances, such as high-power density, fast dynamic response, and strong overload capacity. Therefore, they are widely used in a variety of industrial applications, such as industrial robots, aeronautics,electric vehicle, and numerical control machine. In order to achieve high precision and fast dynamic control characteristics of PMSM, an accurate rotor position measurement is necessary.The traditional method is to detect the rotor position through the position sensor. However, the position sensor not only increase the complexity, volume and cost of the drive system, but also reduce the reliability of the system. So the sensorless control has become an important research point of modern AC drive control. High frequency signal injection method is an effective way to obtain the low speed position information in the many sensorless control methods. Therefore, rotor position estimation method based on the high frequency signal injection is studied in this paper.Firstly, the rotor structure of PMSM are introduced, and the mathematical model of interior PMSM is established. According to the characteristics of the controlled object, the maximum torque per ampere control and id=0 control strategy are discussed in detail, and the sensorless control method of interior PMSM is introduced.Secondly, the principle of the high frequency square wave voltage injection method and the high frequency pulsating sinusoidal voltage injection method to estimate rotor position are described, which focus on high frequency current response demodulation and using rotor position observer to estimate the rotor position. Although these two kinds of high frequency signal injection signal demodulation are simple, its convergence is slow, and there is a risk of divergence in the start-up stage. Therefore, an improved high frequency pulsating sinusoidal voltage injection method is introduced in this paper, because the high frequency signal is injected into the α axis of stator stationary reference frame, the high frequency signal injection sensorless vector control system converges quickly in the start-up stage. However, its rotor position estimation accuracy is related to bandwidth of the filter in signal demodulation. The high frequency signal injection method with fixed bandwidth filter does not has a wide range of speed regulation under the premise of ensuring the accuracy of estimation. A novel method of the high frequency signal injection method using the immune algorithm is proposed in this paper. According to the running state of the motor, the bandwidth of the filter is adjusted online by the immune algorithm, so that high frequency pulsating sinusoidal voltage injection method for static coordinate system has a wide range of speed regulation.Finally, based on the theoretical analysis, sensorless vector control system for interior PMSM based on the immune high frequency signal injection method is analysed by Matlab/Simulink. The experiment platform based on TMS320F28335 is established, and the speed closed-loop experiment is implemented. The experimental verification of rotor position estimation method is implemented based on the immune high frequency signal injection method. Simulation and experiment result indicated that sensorless vector control system based on the immune high frequency signal injection method not only has excellent performance at low speed, but also has good steady-state and dynamic performance at medium speed under ensuring the accuracy of high frequency signal injection identification rotor position. Speed adjustment range of the high frequency signal injection method is widened. |
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