Research On Motor Parameters Identification Based On Three-level Vector Inverters

The inverter plays a more and more important role in energy saving and speed control so that it has been experienced rapid development and wide application. The application of higher voltage and better performance inverter gets more and more attention. Therefore, three-level inverter based on space vector control is a hot topic in the future development. Accuracy of motor parameters is an important factor in determining the inverter performance.In this paper, the research is as followed:calculating motor parameters based on motor datasheet, improving common method of motor parameter measurement, induction motor parameters estimation based on least-squares techniques and induction motor parameters identification with model reference adaptation. The method of calculation motor parameters is simply and flexible but this method is only used in rated frequency and without considering the impact of three-level system. The method of improving traditional experiences performs three tests to get motor parameters. During the experience process, this method is a reliable algorithm considering the specificity of three-level system. The method of induction motor parameters estimation based on least-squares techniques executes the induction motor parameters identification deriving from traditional single phase experience. These methods above belongs off-line identification. In order to further improve the performance of the inverter, the on-line identification is needed. The rotor time constant has the greatest effect on system by analyzing so that a method of rotor time constant identification with model reference adaptation based on rotor flux. A novel algorithm is proposed by analyzing the robust of the system. The improved method has a good robust to load torque.For several identification above, simulation models are build to illustrate the effectiveness in Matlab/Simulink. Meanwhile some key problem is solved during the simulation. The strategy for neutral point voltage balancing control is proposed to settle the neutral point voltage drift in three-level inverter. As phase voltage and current is needed in the identification algorithm, the stator voltage is obtained by voltage reconstruction and stator is obtained by filtering. Hardware platform is described at the end of the paper. TMS320F28335and CPLD is the control core in the platform and the corresponding peripheral circuits are introduced. The experience gets an excellent result using the method of improved traditional experiences.