Research On Sensorless Control System Of Variable Leakage Flux Motor

Currently,in order to alleviate the increasingly prominent environmental pollution and energy crisis,governments around the world are accelerating the development process of the new energy vehicles.As the key part of the new energy vehicles,the motor and its drive system play an important role.In addition,the permanent magnet synchronous motor(PMSM)has been widely used in motor driving system of the new energy vehicles because of its superior performance advantages.However,owing to the limitations such as narrow flux-weakening speed regulation range,the PMSM cannot meet people’s demand for a new generation of electric vehicles.To solve this problem,a variable leakage flux motor(VLFM)based on leakage flux control has become a hot research topic recently.The VLFM has a wide speed range and a high operating efficiency in the whole speed range.However,due to the use of the position sensor in the VLFM drive system,the reliability of the system will be reduced.To solve the above problems,the sensorless control system of the VLFM is studied in this paper.First,the research background and significance of the sensorless control of the VLFM is stated in this paper.Then the state of art for the VLFM and sensorless control are introduced.In addition,the structure and operating principle of the VLFM are explained.Also,the electromagnetic performance of the motor is simulated and analyzed.Furthermore,the mathematical model of the new VLFM is established,and the vector control of the VLFM is studied.The related performance of the drive system of the VLFM is analyzed based on simulation and experiment.Secondly,according to the nonlinearity characteristics of the VLFM’s parameter,the sensorless control technology based on the extended state observer and the sliding mode observer is introduced in detail.Based on principle analysis and simulation comparison,the advantages and disadvantages of the two methods are summarized.After comprehensive comparison,it is concluded that the sensorless controltechnology based on sliding mode observer is more suitable for VLFM.Then,to overcome the influence of inductance change,the off-line inductance measurement method is employed to reduce the observed position error.Additionally,to solve the problems of amplitude attenuation and phase delay caused by the low-pass filter in traditional sliding mode,a generalized second-order integrator(SOGI)is introduced to replace the low-pass filter.Finally,to alleviate the problem that the traditional adaptive detection filter cannot balance the dynamic and steady-state performance of the system,an improved SOGI control method is proposed in this paper.With the proposed method,the structure of the sensorless control system can be simplified,which is easy to be implemented in engineering.Also,the rotor position estimation accuracy and the sensorless operating performance can be effectively improved.In this paper,based on Matlab/Simulink and Maxwell,simulation is conducted on.Also,the experiment platform is built based on dSPACE1007.The experiment of the VLFM drive system with position sensor and sensorless control based on the improved SOGI are carried out.The experimental results verify the validity and effectiveness of the proposed drive system.