Research On Series Triple-circuit Cycloconverter

Energy is widely used in various fields of industrial and agricultural production, business, home by human, but when used in the field of transmission, such as fan and pump, which utilization is low and serious waste, so researching on energy-saving technology is very important, and this paper has researched on series triple-circuit Cycloconverter. Respected to the core of the drive controller used IGBT, in the performance, Cycloconverter researched by this paper is not better, but the Cycloconverter researched by this paper is very advantageous in some high-voltage large-capacity and performance required not very high occasions. It is not subjected to foreign technical limitations, and very appropriate to the occasions of fan and pump. On the other hand, it has advantage on cost.Firstly, the multiple rectifying circuit is analyzed based on a series of triple-phase full-controlled bridge rectifier circuit using the Matlab. The output voltage waveform of the circuit is also analyzed in different controlled angle. Furthermore, this paper derived the relationship between the output voltage of the rectifier circuit and trigger phase shift angle. Then, modeling and simulation are gradually extended to the triple AC/AC inverter circuit system, which in searched on the output with 37.5Hz, 42.86 Hz, 45 Hz.of Cycloconverter and the capacity.Secondly, since the Cycloconverter is not easy to control at the output of low frequency and high voltage large capacity starter motor cannot work directly, so all the work is divided into two phases, the AC-AC inverter operation and soft-start to run. This paper presents a new strategy of soft-start control. Without adding any hardware costs in the case, through the use of it will start from zero speed to the frequency operating speed, and then working in the phase of AC/AC inverter operation. By switching the phase relationship of the output voltages of the triple circuit to control the overall output voltage is an effective approach to limit the starting current of the large capacity motor. The triple circuit was analyzed by the voltage vector analysis and the simulation analysis with Matlab modeling. The results show that the triple soft-start controlling strategy can be applied for the large-capacity motors. The strategy has the advantages of pure-sine-wave output voltage and current and getting the balance of three-phase voltage during the whole startup procedure.Finally, the entire series triple-circuit Cycloconverter system is designed to experimental analysis. The designs include the selecting of controller chips, the synchronization detection circuits, the RC absorption, pulse drive circuit, the current detection circuit, and so on. Moreover, lots of experimental analyses show that theoretical analysis and simulation experiments are correct.