Research On Medium Frequency Three-phase Four-leg Power Inverter

Medium frequency power inverter make use of power electronics technology to transform commom used electricity or other power sources into required medium frequency sine-wave power. Medium frequency power inverter is special, it is commomly used in aviation, aerospace, radar, communications switches and metallurgical fields. Traditional medium frequency power supplier was generated by high-speed generator, thus it needs motor or Diesel engine to supply power. This kind of power supplier is bulky, noisy, poor output stability, with the rapid development of power electronics technology, static medium frequency power supplier may come true.This paper, mainly on the control of the system, hardware and software design of medium frequency power inverter. Medium frequency power inverter during operation, the output will not be the ideal sine wave, due to the dead zone, nonlinear load and other factors, the output waveform distortion, thus it needs a suitable control method, to make the output distortion within the acceptable range. Through comparison of a variety of control methods and simulation, decided to use the control method of the combination of average value PID feedback and Instantaneous value PID feedback. Meanwhile, do research on power loss of output filter inductor of medium frequency power inverter. Inductive losses including iron loss and copper loss, through research we can found that by selecting the appropriate core material, can reduce the iron loss effectively, by dealing with the core air gap can reduce the copper loss effectively. Subsequently, the control strategy commonly used by three-phase four-leg inverter been detailed analysis.This paper, make detail analysis on hardware and software design of the device. Hardware design including the design of the main circuit and control circuit design, make detail analysis on the main circuit topology and the selection of some major component. The control circuit around the DSP TMS320F2812 of TI company to achieve digital control of the whole system, gives the DSP peripheral circuit, voltage and current detection circuit, keyboard and display circuit, IGBT drive circuit, power supply circuit, and analyze the principles of each part of the circuit, and analyze on electromagnetic compatibility design. Software design flow chart of software analyze on main program, initialization procedure, the master program, ADC interrupt service routine, GPIO port inspection procedures and display program, and analyze on reliability of the software. Finally, proved the feasibility of the program through experimental verification.