Simulation Research On Improving Power Factor Of Variable Frequency Speed Variation System

With the rapid development of industrial automation, the use of induction motor has gradually expanded, approximately 1/3 of the electricity consumed in driving fans, pumps, compressors and other electrical equipment, electrical equipment as the power consumption is very large, on how to improve the motor utilization of electrical energy, the economy has great significance in the present energy shortage today. In recent years, with the development of inverter technology, making the application more widely asynchronous motors, DC motors with unmatched advantages. Now AC variable speed induction motor has become the most universal and promising speed control method, with a starting current, large speed range, good energy-saving effect of good features. Although the inverter has many advantages, but there are some problems, high side current harmonic content is large, not only reduces power quality, but also to motor heating, additional losses. In the rectifier conventional drives, they use a simple non-controlled rectifier or phase-controlled rectifier. There is not a controlled, limited voltage range, low power factor, energy can not disadvantage feedback. Dual PWM frequency control system, the introduction of PWM rectifier instead of the traditional rectifier, with good side current waveform for the purpose of which is to reduce higher harmonics, improve power factor, energy saving.Dual PWM inverter system includes a rectifier and inverter in two parts, both of which are controlled by the PWM technology. Since the frequency control technology has been relatively mature, the paper-depth analysis for PWM Rectifier. In this paper, three-phase rectifier voltage source PWM rectifier (VSR) as the research object, first introduced and analyzed its topology, and then derive the three-phase three-phase VSR stationary (a, b, c) coordinate system and the two-phase (d, q) mathematical model of the rotating coordinate system; control strategy introduced three-phase voltage type PWM rectifier direct current control, the paper focused on the direct current control, that is, hysteresis current control, fixed switching frequency and current control vector control PID synchronous start on; to study the three current control strategy performance dual PWM inverter system, detailed analyzes of control principle and design structures for the 600V DC voltage simulation model, as subsequent PWM inverter DC voltage input. Vector control is advanced AC motor control, the PWM inverter part of the induction motor SVPWM control strategy. The simulation section, the first for PWM rectifier with resistive load simulation, and then double PWM co-simulation analysis phase voltage control strategies under different current, phase current and DC voltage at the motor starts and acceleration responsiveness.