Study On The New Auxilary Resonent Commutated Pole Soft-switching Inverters

This thesis focuses on the theme of the three-phase PWM soft-switching inverter, making a further analysis on the topology of the new active auxiliary resonant commutated pole inverter, through the analysis and evaluation of development present situation and topology structure to the three-phase PWM soft switch.Three-phase soft-switching inverter usually includes two types, which are resonant DC link soft-switching inverter and the auxiliary resonant pole inverter, compare to resonant DC link soft-switching inverter, the auxiliary resonant have following advantages:①each phase of the inverter is independently of each other, there is no problem on synchronization of soft-switching operation and the inverter switching, and it can be easily output voltage control using conventional PWM modulation strategy;②without increasing the voltage stress of the inverter switching devices. However, this conventional auxiliary resonant pole inverter have several drawbacks, such as the need of two large capacitors, so there is a neutral point clamped addition, besides, it requires complex detection circuit and peripheral logic circuit to detect the auxiliary resonant inductor current and load current magnitude and direction.After reading the extensive literature, this thesis discusses the status and significance of the development of soft-switching inverter, summing up the conventional auxiliary resonant pole inverter topologies, usually control switch auxiliary tube by detecting the resonant current size, and needs two capacitors to provide a neutral point potential, which has increased the difficulty of control and inverter size. This paper presents a new type auxiliary resonant pole inverter, it avoids the use of two large capacitors of the auxiliary resonant pole inverter (ARCPI, Auxiliary Resonant Commutation Pole Inverter), there is no neutral little bit of change problem. Its three-phase resonance circuit is independently controllable, making the inverter easily to apply various control strategies. At the same time it requires no external detection circuit and all the main switch and auxiliary switch run ZVS and ZVS/ZCS, is conducive to decrease the switching losses and improve the switching frequency, component voltage stress is clamped in the input voltage, allowing the device to the selection and operation of the circuit, when the main switch is turned off, in the period of the PWM control dead zone, the rate of voltage rise at the design stage can be arbitrarily set. Conducive to reducing ground leakage current and reduce conduction and radiation noise.Then, this paper analyzes the working mechanism of the circuit topology, and soft switches operation mode of the main circuit of the three-phase soft switching inverter, different mode equivalent circuit is given, and each mode has carried out a detailed mathematical analysis, establishing mathematical model, and determined the basic PWM control strategy, presenting the loop parameter design method, and carried out the Simulink simulation, meanwhile, it analyses the energy of the intermediate resonant components, as well as identified some problems of its existence.Finally, a summary of soft-switching three-phase PWM inverter is presented, pointing out the existing problems and further research prospects.