Study On Two-stage Matrix Converter Used For Variable Speed Constant Frequency Power System

This paper studies variable-speed constant-frequency power system based on two-stage matrix converter, which combines the H-bridge excitation circuit with the main power circuit according to the DC bus owned by two-stage matrix converter. The whole system not only combines the H-bridge excitation circuit with the main power circuit but also realizes that the main power circuit can supply constant frequency and constant value voltage, which is on the condition that the given speed of generator is wide.First, this thesis introduces the topology and operating principle of two-stage matrix converter, and introduces two kinds of double space vector modulation strategies which are non-zero vector rectifier modulation strategy and zero vector rectifier modulation strategy, a simulation model of two-stage matrix converter system is built by the Matlab software, then the experiments of the system verified the control strategy mentioned. Secondly , the modulation strategies of two-stage matrix converter,H-bridge and the system are detailedly analysed ,which is used in the system combined by the hybrid excitation synchronous machine (HESM),two-stage matrix converter and the H-bridge excitation circuit, the system's model is built by the Matlab software, then the experiments of the system further verified the control strategy mentioned. Finally, the practical implementation of variable-speed constant-frequency power system based on two-stage matrix converter was discussed and a experiment platform including two-stage matrix converter and H-bridge excitation power circuit was built. The control method of the two-stage matrix converter was carried out in DSP and CPLD. The common emitter bidirectional switch cell arrangement of the two-stage matrix converter was consist of two diodes and two IGBTs connected in anti-parallel. The hardware composition and design expressions of software of the whole system were given, which provides a technical basis for the further practical study .