Research Of Medium-voltage Three-level PWM Wind Power Converter Based On High Voltage IGBT

NPC three level PWM converter is used more and more widely, and it becomes a research hotspot. Therefore, this article, based on the three-level topology with a experimental basis of medium voltage three-level PWM wind power converter, gives some research and analysis on medium voltage three-level converter from the high voltage IGBT perspective.Firstly the three-level converter application status and development direction are elaborated, then from three-level topology, IGBT devices and high voltage IGBT driver three aspects, three level PWM converter development status is discussed. Multi-level topology includes fly capacitor, NPC and cascade multi-level topology, and the advantages and disadvantages of each kind of topology are introduced. IGBT now becomes the mainstream switching device, and take IGBT and IGCT devices generated subsequently compared, the advantages and disadvantages and the application range of IGBT are presented. IGBT is adapted to5MW or lower5MW grade converter.IGBT power loss and temperature rise analysis based on the diode NPC three-level PWM converter are a major focus. Firstly, through theoretical deduction and calculation the loss of power devices and temperature rise are given; then by Mitsubishi official simulation software melcosim, the power loss results are gotten. Compared melcosim simulation with formula calculation results, it verifies that the formula is derived for the accuracy of calculation results. Through the calculation of device power loss and temperature rise in the three-level converter, several IGBT options that save cost are put forward. Now NPC three-level topology clamp diodes are replaced by IGBT modules, without changing the control strategy and control mode, a IGBT module option is proposed, and then power loss and temperature rise calculations of power devices in the program are given. Though the calculated results, the IGBT option are verified right.A high-voltage IGBT driver board is designed and produced. Its control software, control circuit and functional description then are described. And then through the double-pulse experiments IGBT driver board are tested in the tuming-on and turning-off process, and the appropriate gate resistor to ensure the appropriate di/dt and du/dt is selected.IGBT in parallel to enhance the capacity of the converter, are analyzed sub-classified as the IGBT components parallel and three-level bridge arm parallel two ways. First a brief introduction of the IGBT component parallel is given. And then the bridge arm parallel is a focus. Though calculation and simulation, the method of string inductance is proved practical. And this method without any attachment conditions for system control, is relatively simple to achieve.Finally, though the test of three-level components parallel and medium-voltage three-level PWM wind power converter mutual feedback, the effect of current sharing in parallel, the IGBT switching characteristics and the characteristics of the converter at both no load and full load are verified.