Application Of Rotating High Frequency Signal Injection In Elevator Door Sensorless Drive System

With the rapid development of permanent magnet synchronous motor(PMSM)control technology,the permanent magnet synchronous motor has been widely used in the elevator door control system.In order to obtain the excellent performance of PMSM,mechanical position sensors are used to obtain the position and speed of the rotor,but,with problems such as high cost,maintenance requirement and robustness and poor reliability of the control system.To reduce the cost and complexity of the elevator door system,sensorless control of permanent synchronous elevator door system is studied.A position sensorless control strategy of PMSM is proposed in this paper based on rotating high frequency voltage signal injection.A new signal process based on the time delayed filter is proposed to reduce phase lags in signal processing and amplify signal to noise ratio of high frequency current.The time delayed filter is used to extract high frequency current in the stationary frame and negative sequence high frequency current in a reference frame synchronous with the positive sequence carrier signal current.In order to obtain the rotor position information,the rotor position observer is presented based on a phase locked loop(PLL).And the parameter design method of the PLL is studied according to the design criteria of resonant peak in the minimum closed loop.To overcome the adverse impact of the negative high frequency current's magnitude on the performance of the PLL,the normalization for PLL is conducted,which can effectively improve the anti-noises of the PLL.To resolve the starting problem,the magnet polarity of estimated rotor position is identified by constant magnetic field method,which can also make up the position error between the position of spatial saliency and the position of magnet polarity.On the basis,a sensorless vector control system of the elevator door is designed.Finally,a sensorless control algorithm is designed by assembly language,according to the characteristics of elevator door system.Experimental verifications are carried out on a platform of elevator door.The experimental results show that the proposed sensorless control method can achieve the basic open-close function in the elevator door system,which makes some reference value in the field of engineering.