Research On Energy Saving Control System Of Permanent Magnet Synchronous Motor

Energy shortage is a serious problem of modern society,along with the development of technology,the electricity consumption of the whole society is rising.Motor electricity consumption accounts for more than half of the total electricity consumption of china,but in general,motor control system operating efficiency is low.So the research on energy optimization operation of motor control system could bring substantial economic benefits.Permanent magnet synchronous motor has many advantages,such as high efficiency and good reliability,which can meet the basic demands of energy control system,and it has become the first choice of energy-saving motor control system.However,permanent magnet synchronous motor is a non-linear electro-mechanical transducer system,in its control system,there are lots of interference factors can directly affect the permanent magnet synchronous motor control system performance,such as current coupling,flux saturation,parameter changes and many other interference.Therefore,it is very necessary in both of theoretical and practical aspects to improve the performance and robustness of the energy-saving control strategy of permanent magnet synchronous motor.It is easy to measure and change the parameters of the motor.This paper aimed to do the online estimation of permanent magnet synchronous motor parameters.The on-line estimation of motor parameters can be divided into two parts: dynamic model linearization and identification algorithm.Firstly,the linearization of permanent magnet synchronous motor dynamic model is improved by using the Pade linearization method.Then,the multiinnovation least squares algorithm is introduced to estimate the parameters of the permanent magnet synchronous motor,also used fuzzy control algorithm to improve the selection strategy of forgetting factor in online parameter estimation algorithm,gaining a significant upgrade in the accuracy,speed and stability of the permanent magnet synchronous motor multi-parameter on-line estimation.There are two main kinds of motor energy saving control strategy,the loss of the model method and input power search method.The mathematical model of the loss model is built based on the motor parameters,the controller calculates the current reference value based on the loss model,and the loss model's accuracy and robustness are affected by the motor parameters.Therefore,the on-line estimation of permanent magnet synchronous motor parameters can improve the performance and robustness of the loss model controller.In this paper,the on-line parameter estimation algorithm is used to estimate the motor parameters in real time,the parameter estimates input into the loss model controller to estimate the reference current in order to get a more accurate current reference.The on-line parameter estimation reduces the interference in the loss model by the change of the motor parameters,enhances the robustness of the control algorithm,finally achieved a more efficient permanent magnet synchronous motor control system.Input power search method can be used in the local optimization problem,finding the most stable and lowest working point of the motor input power by detecting the inverter DC side power and control the motor input voltage.The input power search control strategy has the disadvantages,such as slow convergence speed and large torque fluctuation.In this paper,using the permanent magnet synchronous motor loss model to determine the initial search interval which should be used in the search method,so it can improve the interval accuracy and the algorithm convergence speed of this search method..At the end of this paper,the energy saving control of permanent magnet synchronous motor based on loss model energy saving strategy is built on dSPACE semi-physical simulation platform.Experiments show that the on-line parameter estimation algorithm can improve the efficiency and robustness of the energy saving strategy of the loss model.