Research And Design Of Cascaded High-voltage Converter

Along with the development of the world first Asynchronous Machine in 1855, the ac motor especially the squirrel cage ac motor, for it's simply structure, solidity and low-cost, it is wildly used in industry. But in the filed of high voltage AC motor speed control, most of it adopt constant speed until 20 century. The need of saving energy is release by the birth of high power electronic converters. Now it is a hotspots in power electronic field. The cascaded high voltage converter is one of the most important circuit topology. The cascaded high voltage converter has merits such as: input side has less pollution to the electrical net; output voltage approaches to sine wave so that it doesn't need output filter; structure is simple and easy to be modularized; control method is easy to be realized and so on. These merits make cascaded high-voltage converter to be widely used in field especially as blower fans and water pumps which don't require exactitude speed control. The main work in this paper is:1 Introduced the most common circuit topology of high voltage converter. And analyze their advantages and disadvantages. Take research on the cascaded high-voltage converter's basic topology in details, explain multiplexing rectify circuit and invert circuit and cascaded cells.2 For the control method of high-voltage converter, the most common usage of VVVF control and vector control was introduced. For the PWM arithmetic explain the subharmonics PWM, triangular carrier phase shifting PWM, carrier phase shifting SPWM, carrier phase and modulate phase shifting SPWM and SVPWM. Model and emulator of these control strategies using MATLAB.3 The hardware design of the cascaded high-voltage converter was completed, using VVVF control and carrier phase and modulate phase shifting SPWM. Using the dual DSP control board control the convert system.4 Design the system's man-machine interface using Eview touch panel.5 Completed a experiment high-voltage converter, compare the experiment result from the practicality and emulator.