Research On Parameter Identification And Drive Control Of Dual Three-Phase Permanent Magnet Synchronous Motor

Compared with the traditional three-phase motor system,the multi-phase motor drive system is more suitable for special occasions with the characteristics of low-voltage high-power output,high operation reliability and high control flexibility.Among all kinds of multi-phase motors,multi-phase permanent magnet motors have the advantages of small volume,light weight,high power density and low loss.At the same time,China is relatively rich in rare earth resources,which provides a prerequisite for the practical application of multi-phase permanent magnet motors.In this paper,the dual three-phase permanent magnet synchronous motor is used as the research object to study its parameter identification and drive control algorithm,in order to obtain better control performance:Firstly,the mathematical model of the dual three-phase permanent magnet synchronous motor based on the natural coordinate system is established,and the mathematical model based on the natural coordinate system is decoupled by the two coordinate transformations of dual d-q and space vector decoupling.The mathematical model of the motor derived by the two different decoupling methods is established,and the correctness and consistency of the two models are verified by simulation.Secondly,the basic voltage vectors in the subspace and subspace are obtained by the space vector decoupling transformation of the dual three-phase permanent magnet synchronous motor.At the same time,based on the volt second balance criterion,the two vector SVPWM modulation and the four vector SVPWM modulation are derived and calculated respectively.The vector control block diagram of dual three-phase permanent magnet synchronous motor mathematical model built by two different methods is designed,and the advantages and disadvantages are analyzed.A dual three-phase permanent magnet synchronous motor drive control system based on model predictive control is built.Aiming at the problem that the motor current and torque fluctuate greatly due to the large number of iterations of traditional model predictive current control and the limited number of output reference voltage vectors,a current loop optimization algorithm based on analytical function is proposed,which calculates the amplitude and direction of the reference voltage vector at one time through analytical function,and is modulated by four vector SVPWM.Aiming at the problem that the transient performance of the motor is limited because the current loop is restricted by the speed loop in the traditional model predictive current control,a bi second-order model predictive control algorithm is proposed,which makes the current loop and the speed loop adopt the second-order model predictive control.The above two algorithms are integrated,and the feasibility and effectiveness of the proposed algorithm are verified by simulation.Thirdly,the reasons for the change of motor parameters are deeply analyzed,and the basic least square method,the least square method based on forgetting factor and the recursive least square method based on forgetting factor are compared.Aiming at the problem that the least square method based on the fixed forgetting factor can not take into account the convergence speed of the identification algorithm and the fluctuation after convergence and stabilization,and the resistance identification convergence speed is slow when the motor resistance and the direct axis current are small,a recursive least square method based on the parameter modified dynamic forgetting factor is proposed.This algorithm dynamically adjusts the forgetting factor based on the prediction idea,The compensation term of resistance parameter identification is added to accelerate the convergence speed of resistance identification,and then the parameters of the proposed algorithm are adjusted in the form of simulation,and its effectiveness is verified.Finally,Infineon TC264 is used as the main control chip to design and build the experimental platform of dual three-phase permanent magnet synchronous motor,and the motor drive system program is designed and written.The algorithm proposed in this paper is verified by experiments.