The PWM Modulation About The High Voltage Frequency Converter Control System Basic On The Multiple Voltage

The DC motor is gradually replaced by the AC motor for AC motor's simple structure and easy to maintain. And AC motor has been the main character in the field of drive. Especially in the filed of high-voltage and high-power, the AC motor has much advantage than the DC motor. With the development of frequency conversion, the speed control of AC motor is very easy. The frequency conversion of low-voltage motor has been used for practice successfully. And in the theory of frequency conversion, low-voltage motor has accumulated a wealth of experience parameters. But in the field of high-voltage, the experience for the low-voltage system still can't be used directly for the voltage level of power element is still insufficient. The structure of high-voltage is very complex and there are many new kinds of algorithms and theories about it. In practice, the harmonics and power factor are still the hot point in study. With the widely use of high-voltage motor, the requirements of high-voltage frequency converter get much further, not only to achieve the purpose of variable speed and saving energy, but also to ensure the green character of converter itself. Therefore, further study of the structure and algorithm to the high-voltage is still very important.In this paper, the main topology and principle of high-voltage will be analyzed first, and then the multiple voltage input base on the cascaded high-voltage converter and the algorithm of the output base on the PWM will be discussed. After that, the PWM algorithm of magnetic orientation will be analyzed qualitatively and quantitatively. Then, the motor and the converter will be analyzed together and a new suitable algorithm for the cascaded high-voltage converter will be bring out, in order to get better control effects.