Study On Speed Regulation Technology Of Single Phase Motor Based On Microcomputer

With more and more electrical appliances become necessity in People’s Daily lives, such as household appliances, electric tools, electric roller shutters. Most of them use small single-phase motor as power, which obviously influence our standard of living. In order to deal with the problem of energy shortage and environmental protection in the world, the industrial field mostly uses the "speed adjustment and energy-saving" project, achieving the purpose of energy conservation and consumption reduction and also protecting environment. For the energy saving and performance improvement in the field of household electrical machines,the Single-Phase AC Machine Speed Control method comes into mind. With the development of the control theory, power electronic technology and device cost reducing, people pay more attention on the application of frequency control to single-Phase motor.This paper mainly study the single-phase motor open-loop frequency control device based on AT89S52, introducing several control methods of single phase motor and frequency control theory, The main works are as follows:1.This paper gives the double tangent sampling method, taking several typical SPWM(Sine Pulse Width Modulation)control sampling method as theoretical basis, by natural sampling method standards, focusing on switching time and harmonic coefficient between secant sampling method and double tangent sampling method. The results show that the double tangent sampling method is closer to natural sampling.2.To verify the control scheme as shown in the above, we establish the model by Matlab/simulink. It generates bipolar SPWM driving signal by natural sampling method, realizing the single motor speed regulating simulation, getting the output current of inverter and motor speed waveform.3.Designing the software and hardware of speed regulation system, selecting and calculating parameter of the inverter, rectifier, filter, IGBT drive circuit and other peripheral devices. AT89S52 is the core of control circuit components, which processing speed is limited. Using double tangent sampling method’s switch time point to get SPWM width of high and low level. Then obtain timer initial value, write look-up table program, using timer interrupt to output SPWM waveform and prepare the over-current protection program and the interrupt program. Through the system test, obtain the inverter output voltage waveform and motor speed table. The results show that this system can work, running well, meet the speed requirement, achieve the design purpose.