Research On Dynamometer With Feed-back Energy

Dynamometer is a equipment loaded dynamometer, that primarily used to detect thetorque and speed such as a variety of engines, motors, fans, internal combustion engines,hydraulic pumps, gear boxes and other power machineries. Most of the traditionaldynamometer can produce energy that is consumed and dispelled. in the form of heat energy.This thesis researches on a new type of dynamometer that it is the advantage to use thefeedback-energy. The dynamometer can transform energy into electricity and feedback theenergy to AC mains of the test machine, rather than transform energy into heat energy anddrain it. In order to control the operating frequency, the main circuit of the dynamometer isvariable-frequency of voltage source of"AC-DC-AC". When the synchronous speedcorresponding to the operating frequency of the dynamometer is lower than the speed of thetest machine, the dynamometer is used power state and provided the load for the test machine.At the same time, the mechanical energy of the test machine transforms into electrical energyand transmits to the circuit of DC. Then using the technique of converter, the electrical of DCchanges the three-phase power with the same frequency and feedbacks the grid. On thecontrary, the dynamometer absorbs the energy from the electric grid and operates.In order to simplify the analysis, the main circuit is divided into"AC-DC"and"DC-AC".The control of"AC-DC"of the preceding stage adopt in the technique of three-phase PWMrectifier that not only can make the current sinusoidal of the line and operate high powerfactor, but also can achieve two-way flow of energy and generate a stable of DC bus voltage.Using the idea of direct torque control of motor, the later part of"DC-AC"can control themotor of dynamometer and it is not only can reduce the parameters of machine, but also canreduce the coordinate transformation and calculation. Finally, using the DC bus voltage as the linkage between the three-phase PWM rectifierand the DTC control of asynchronous machine, the mathematical model of the dynamometerof feedback energy is established and is researched in the MALAB/Simulink. The hardwareof the design contain DSPTMS320F2808, interface circuit if the IPM, the signal detectioncircuit and the interface of serial communication. The last, the flow chart of the system isdesigned.