Efficiency And Energy-Saving Potential Estimation Model Of Motor System Based On On-line Monitor

The key of motor efficiency on-line monitor is how to obtain the energy efficiency level of each link, and then evaluate the energy-saving potential. Based on systematic analysis of different evaluation methods of energy efficiency, this thesis proposes an efficiency on-line monitor model combining equivalent circuit method with parameters identification method. Further, this model can be used to evaluate the actual motor efficiency. The main works of this thesis are as follow:1) Comparing all kinds of motor efficiency test method, the characteristics of various kinds of on-line test method of energy efficiency are analyzed by combining with efficiency on-line monitor and energy saving potential problems. The problem of how to analyze the motor system efficiency and energy saving potential with equivalent circuit method is studied. The efficiency monitor method combining equivalent circuit method and parameters identification method is proposed;2) By recursive least squares algorithm, the parameters identification of motor equivalent circuit is realized. Through discussing the problem of identifiability, the effect of input signal to identify performance is analyzed. Based on this, the iteration formula of recursive least squares algorithm is studied and the accuracy of identification is analyzed. The simulation and experiment are made to verify the accuracy of identification;3) For the problem of poor identification with recursive least squares algorithm, the extended Kalman filter is used to identify the rotor resistance. The identification principle of extended Kalman filter is studied and the iteration process is derived. With model of MATLAB/SIMULINK, the dynamic identification performance of rotor resistance with extended Kalman filter is analyzed.4) Combining parameters identification method and efficiency test method, equivalent circuit method is used to establish the induction motor efficiency monitor model. One hand, the motor efficiency on-line monitor is accomplished, on the other hand, monitoring efficiency of different motors can supply basis to analyze the energy-saving potential. Finally, using the model to analyze an efficiency of a 5.5kW motor, the verification is made by comparing with standard efficiency test method B.