The Research Of PMSM Rotor Position Detection Method Based On High Frequency Signal Injection

In the permanent magnet synchronous motor control system, there are defects due to the installation of mechanical sensors, including the increasing of system cost, large volume, reliability reduced and vulnerability to working environment. In recent years, scholars from various countries started to focus on sensorless control system. Among the sensorless control technologies, high frequency signal injection method becomes a focus of research for its obvious advantages, so the rotor position detection method based on this high frequency signal injection is studied in this paper.Firstly, the theory of rotating high frequency voltage signal injection method and pulsating high frequency voltage signal injection method in rotor position detection is presented in this paper, and further derivation and collation of the relevant high frequency current response formulas are presented. High frequency voltage signal injection method is a novel sensorless technique which is suitable for the motor with a certain rate of salient. In this method, a three-phase equilibrium of high frequency voltage or a sine(cosine) high frequency excitation voltage signal in the estimated position of rotor direct axis, and then rotor position information can be derived by detecting corresponding high frequency current response and applying a specific signal processing.Secondly, permanent magnet synchronous motor vector control system based on rotating and pulsating high frequency voltage signal injection method are constructed separately using MATLAB and static and dynamic tracking performance analysis is carried out. First, feedforward compensation is done to the cross-coupled term in permanent magnet synchronous motor stator voltage equation. The current and speed PI regulator parameters are designed using the left half plane zero-pole cancellation method. The speed PI regulator is also designed to anti-windup applying back-calculation. Second, the parameters of the position tracking observer are designed. In the vector control system based on rotating high frequency voltage injection method, rotor position error information is obtained using rotor position estimation with the measured values directly heterodyning calculation, and this rotor position error is the input signal of the position tracking observer. At present, the design of the position tracking observer parameters is relatively simple, and designs and tests these parameters applying the method of zero-pole configuration. Simulation results show that permanent magnet synchronous motor vector control system of rotating, pulsating high frequency voltage signal injection method can detect the rotor position with high tracking accuracy of static and dynamic.Finally, the stator resistance effect of rotor position estimation in high frequency voltage signal injection is investigated. Beginning with the constructing dynamic equation of PMSM mathematical model, steady state expression of the high frequency current response is derived. Via detailed formula inference and theoretical analysis, the conclusion that stator resistance influences the rotor position estimation in rotating high frequency voltage signal injection method is received, while in pulsating high frequency voltage signal injection method, the influence of stator resistance rested with signal extraction method. Rotor position estimation error will be obtained if only one of high frequency positive sequence and high frequency negative sequence is applied to extract high frequency current, while not if both are applied. In view of rotor position estimation error in rotating high frequency voltage signal injection caused by stator resistance, compensation formula is given and ignoring the stator resistance in rotating high frequency voltage injection method is another source of bringing rotor position estimation error. Then pulsating high frequency voltage signal injection is analyzed theoretically from two different angles, and the form of rotor position estimation error signal in different signal extraction methods is discussed, pointing out internal mechanism of stator resistance influence of rotor position estimation error in pulsating high frequency voltage signal injection.