The Research On The System Of The AC Asynchronous Electrical Dynamometer And Its Soft Sensor Model

The dynamometer is important equipment in the power testing system for the drive machine and transmission machine. The AC asynchronous electrical dynamometer with squirrel-cage rotor is used widely since it has a simple structure, widely working range and good control performance. Under the control of transducer, the AC asynchronous electrical dynamometer can not only proved the load torque for power testing, but also drag the machine when it need cold running-in. Because the output power of the AC asynchronous electrical dynamometer can be feedback to the power grid through inverter feedback, the energy feedback for the system is realized and the electric circle is achieved easily. This paper studies on the system of the AC asynchronous electrical dynamometer which include constitute of the system, and the soft sensor technical in the system.First, this paper discuses operation principle and stability condition of the AC asynchronous electrical dynamometer based on a motor engine test bed. After a discussion for the AC asynchronous electrical dynamometer's motor, the math model for the whole system is build. The auxiliary variables for the soft sensor model to build system are accepted by the hardware designed in this paper.Second, a soft sensor model for the system of the AC asynchronous electrical dynamometer that is based on artificial neural network is proposed. Then this model used to the speed, torque identification of the system. The simulation and the experiment prove that the soft sensor model can estimate the quantity and has several errors due to their sensitive to the influence of the parameters and losses of the AC asynchronous electrical dynamometer.In order to improve the estimate precision of the speed and torque, and overcome the parameters influence, a soft sensor model based on these function forms using the Support Vector Regression (SVR) which can be used to approximate nonlinear function in the whole region is put forward. The experiment prove that the precision of estimated is better than the soft sensor model based on the artificial neural network model. The training result and the experiment prove that the soft sensor model based on the SVR has a good ability to estimate the speed and the torque of the AC asynchronous electrical dynamometer system. It also has good robust performance.At the last in this paper, the applied foreground of each soft sensor model is discussed according to the national standards. The facts which lead the errors are analyzed also. For the further research, the method to decrease the errors is proposed.