Design Of Power Factor Compensation Device For Asynchronous Machine

The electric energy is the main energy of national economy and people's lives,it is a kind of clean,environmental friendly,convenient and quickness energy.Its proportion in the terminal energy consumption is an important index to evaluate modernization standards of a country.Machine consumption accounts for about 64%of global electricity,especially in the industrial area,for the proportion can reach about 75%.However,the rated power factor of asynchronous machines is generally only 0.8,and in light load or uneven load conditions only 0.2-0.85.Therefore,the study of a device to compensate power factor for asynchronous machines,can optimize the motor operating,energy efficiency,and save electric energy.The topology of power factor compensation for open-winding asynchronous machine is studied and designed in this paper,by analyzing the electromagnetic principle and structure of asynchronous machine,reviewing document literature and referring the topological structure and control method of double-ended inverter control.The control method of power factor compensation designed under the principle of instantaneous reactive power and power factor compensation.The model of open-winding asynchronous machine is built in Matlab.The simulation verified the validity and feasibility of this design.The print circuit board of main circuit,control circuit,sampling circuit and power circuit of power factor compensation device are designed in Altium designer.Based on DSP TMS320F28335,the control program is written in CCS3.3 using C language,combining with the hardware circuit.The control method of power factor compensation device uses SPWM.The related experiments is carried on by the experiment platform based on 0.75kW asynchronous machine.Simulation results show that when the machine with power factor compensation device working at rated voltage and 25%-125%rated load,the reactive power can reach almost zero,power factor can reach 1.The experimental results show that the can achieve the power factor compensation function;but due to the flaw of the designed hardware and software system,under rated voltage and 50%of the rated load,reactive power of motor will decrease and the motor power factor increase from the original 0.38 to about 0.53,the power factor is increased by about 15%.Under rated load,motor power factor's improvement is not very obvious.