Research Of AC Asynchonous Motor Frequency Control Based On Embedded

The frequency control technology of the asynchronous machine with the high performance is one of the important means to save the energy and improve the efficiency.This thesis mainly studies the speed sensorless how to contribute to the regulation system's operation and application of the asynchronous machine by the vector control.Starting with the mathematical model of the asynchronous machine,the stator current decoupling is realized by using the rotor flux oriented vector control method and taking advantages of the coordinate transformation to simlify the voltage and flux chain equation.The vector frequency control system is constructed by SVPWM and the speed sensorless technology.In order to obtain the accurate amplitude and phase of the flux chain,the traditional flux observation voltage model is improved.The the pure integral is replaced by the first order inertial link.And the phase error is compensated by the flux chain filter signal generated by the excitation current.The model reference adaptive method is applied to accurately estimate the rotational speed.By designing the PI regulator,the correction of speed closed loop and current closed loop is realized.When it starts,adjusts the speed or changes the load,the system can swiftly respond and have the pretty strong anti-interference ability.By the voltage reconstruction technique,the three phase voltage of the stator can be obtained,measuring the DC bus voltage.When all the modules and the whole system are simulated under the condition of starting,changing speed and loading,the rational speed will response the smaller overshoot.However,the speed will decrease when the load is suddenly added and then it can recover quickly.When the system is stable,the error between the actual speed and the estimated speed is less than 2r/min.Thus,the following performance of the machine's speed estimation model is good.According to the theoretical simulation,the system's hardware and software are designed,on the basis of embedde.The main circuit of AC-DC-AC converter is applied to the system and the intelligent module of IPM are used in the inverter.The DC bus voltage and stator side three-phase current signal detection circuit is designed.Establishing one experimental platform to detect the stator current and rational speed,it shows that the speed sensorless frequency control system has a good dynamic response ability.