Research On Sensorless Control Strategy Of Permanent Magnet Synchronous Motor Based On Hybrid Transmission

As the most industrialized and market-oriented energy-saving vehicle model,hybrid electric vehicles are receiving increasing attention.Permanent Magnet Synchronous Motor has the advantages of small size,light weight,simple structure,high power density,and fast dynamic response,making it the primary choice for hybrid electric vehicle motors.Hybrid electric vehicles involve switching between multiple modes.When the motor cuts in at high speed,it is necessary to quickly and stably achieve synchronous speed on both sides of the clutch to complete bumpless engagement.Mechanical position sensors can provide accurate position information,enabling PMSM to meet the above requirements.However,installing mechanical position sensors can increase system cost and volume,increase system complexity,and limit system application scenarios.Therefore,it is of great significance to study a position sensorless algorithm that can achieve PMSM bumpless access in the medium to high speed domain.This article establishes the basic structure and mathematical model of permanent magnet synchronous motors and clutches for vehicles.Based on this,the implementation method of space vector pulse width modulation technology is proposed.Three vector control strategies,i_d=0,maximum torque current ratio,and weak magnetic field,are studied,laying a theoretical foundation for the research of sensorless control strategies for permanent magnet synchronous motors.The traditional sliding mode observer in the medium to high speed domain,due to the use of symbol functions,low-pass filters,and rotor position compensation devices,can cause high-frequency chattering,phase delay,and system complexity issues,making it difficult for the motor to meet the requirements of non jerky meshing.In response to the above issues,this article designs an improved super-twisting sliding mode observer,which uses the T(s)function instead of the symbol function to reduce chattering,introduces the super-twisting algorithm to avoid the use of low-pass filters,designs a phase-locked loop to replace the arctangent function to simplify the system and improve observation accuracy.To improve the speed estimation performance of the improved super-twisting sliding mode observer in the wide speed domain,an improved adaptive super-twisting sliding mode observer is further proposed.By introducing a sliding mode gain that varies with speed,the operating speed domain of the improved super-twisting sliding mode observer is expanded.Studied high-frequency square wave voltage injection algorithm and V/F control algorithm.Compare the two methods of obtaining position error signals using high-frequency square wave voltage injection method and prove their equivalence.Comparing the phase locked loop and Luenberger position observers,simulation verifies that the Luenberger observer has better dynamic performance.Adopting a simplified current separation strategy to extract fundamental and high-frequency currents,avoiding the impact of using filters on system bandwidth.For the V/F control algorithm,design the V/F control curve,select the compensation voltage,and verify the feasibility of the algorithm through simulation.By comparing the advantages and disadvantages of high-frequency square wave voltage injection method and V/F control method,and combining them with practical application systems,a simple and effective V/F control algorithm is selected for zero low speed starting of the motor,achieving the full speed range operation of the PMSM sensorless control system.Simulate the construction of an experimental platform for sensorless control system of permanent magnet synchronous motor based on hybrid transmission,and conduct experimental analysis on sliding mode observer algorithm,full speed domain algorithm,and dual motor meshing in medium and high speed stages based on this platform,verifying the correctness and effectiveness of the theory and simulation.