The Research Of Speed-shifting Device By Using High Voltage Converter

At present there are a great many speed-shifting methods on asynchronous machine,but the highest efficiency, best performance and most popular one is using converters. Via using high voltage converter people can build up an AC speed-shifting system with excellent dynamic behaviour. It is the direction of development of AC speed-shifting. Asynchronous machine is supplied by converters in AC frequency-shifting and speed-shifting method. The speed of the machine can shift smoothly in a wide range.The converter can change invariable voltage or invariable frequency AC signals into adaptable voltage or adaptable frequency AC signals. Now there are two types of converters:AC-AC converter and AC-DC-AC converter. AC-DC-AC converter has a DC unit to smooth the waveform which does not exist in the AC-AC converter. There are many advantages of speed-shifting method by using converter, such as lower noise, fewer harmonic, more stable and so on. Furthermore the method can save more energy.So with the development of power electronics technology the future of the speed-shifting method by using converters will be much more better.This paper first introduces the development trend of speed-shifting technology, as well as speed-shifting system by high voltage converter.The paper also contains the elementary plan of the test device. And then the paper narrates the meaning and emphases of the speed-shifting system by high voltage converter.An induction voltage regulator is equipped in the test device . For the protection of the induction voltage regulator, this paper makes a brief introdution of the induction voltage regulator as well, which covers the basic principle of single induction voltage regulator and double induction voltage regulator.As a special asynchronous machine, the protection plan of asynchronous machine can be used on induction voltage regulator,too. Comparing induction voltage regulator with normal asynchronous machine,the paper gives up some protection plans of induction voltage regulator.After analysing the topology of Speed-shifting device by high voltage converter,the paper calculates the parameter of some relative elements.Finally the paper builds up a model of the Speed-shifting system by using simulation tool Simulink of MATLAB software, and then simulates some workings of the device, such as normal running and short-circuit fault, and gets some data.The paper gives up some protection plans of the speed-shifting system via analysing the data, prepares for future research.