Variable Speed Load Tracking Control Of AC Motor

The AC motor is a power plant that converts electrical energy into mechanical energy,it is widely used in industrial and agricultural production because of its simple structure,low price and solid durable. The load carried by a running AC motor is not often constant,if the motor runs with light load or no load the efficiency and power factor will be very lowand this causes serious waste of energy. So the energy consumption problem of the motorcontrol has great significance to the economic and social development. In this paper, ACmotor is the research object and its related control technology will be studied.First, the operating principle and mathematical mode of the AC motor are studied, andthe power equilibrium relations of the AC motor are analyzed. The speed governingcharacteristic of variable voltage and variable frequency and the relation between runningparameters when the load changes are studied, simulation is done to analyze the influenceof load variation on the motor running, the AC motor control strategy to track the loadchanges is studied.Second, SPWM modulation technique principles are analyzed and the inverteralgorithms are studied and a series of simulation experiments are also done. The hardwaredesign of the inverter based on DSP (TMS320F2812) is accomplished. It includes themain circuit of inverter, the drive circuit and the DSP controller circuit. The output voltage,frequency and phase of the inverter can be changed and it meets the needs of the control ofthe AC motor.Finally, the hardware platform of AC motor load tracking control system is build. Thesystem comprises an inverter controller and detecting circuit of the motor parameters, andcircuits are sure to be simple and reliable. The experimental platform is used for someexperimental study of the AC motor control and then output waveform and experimentaldata are measured. Simulation analysis and experiment result can indicate the AC motorvariable speed load tracking control strategy used is feasible. The system can realizefrequency converting control of the AC motor and adjusting the input voltage according totracking the variable load, to make sure the motor is running at its best point and it improves the efficiency of the motor running. The study of this paper has greatsignificance for the implementation of the AC motor energy-saving control and has broadapplication prospects.