【作者】 韩烨；

【导师】 冯健；

【作者基本信息】 东北大学 ， 电力系统及其自动化， 2009， 硕士

【摘要】 近年来,随着PWM逆变器的发展,功率变换器的设计出现了根本的变化,它从笨重庞大的工频变压器变成了体积小重量轻的高密度功率变换器,变换器的整体效率也大大提高,这有利于PWM逆变器的设计及推广应用。然而,随着我国工业的发展和能源需求的增加,高效节能的变频器成为人们研究的热点。传统的逆变技术成熟可靠、应用广泛,但存在体积大、音频噪音大、系统动态特性差等缺点,功率逆变器的设计中软开关技术被认为是一种先进的技术。为了解决传统缓冲电路存在的损耗,提出了无损软开关技术,根据有无辅助开关器件,无损软开关技术分为有源无损软开关技术和无源无损软开关技术。有源无损缓冲电路虽然能降低开关损耗,但结构和控制都比较复杂。无源无损软开关技术不仅能减少开关损耗、削弱噪声,而且电路简单,成本低,可靠性高,近年来得到了广泛的关注和研究。软开关逆变器主要通过辅助开关器件控制谐振过程,控制方式复杂并且不易实现。对此本文研究了一种吸收式软开关拓扑,实现了主开关管的零电流开通和零电压关断,此电路拓扑的特点是桥臂上下管共用同一开通吸收电感和关断吸收电容,在优化主吸收结构的基础上,添加了少量的电感和二极管元件,实现了附加元件的最小化,又以电容构造电压源,实现了能量回馈及吸收元件复位。在分析整理相关研究文献的基础上,对软开关逆变器技术的发展现及状做出了较为详细的综述,论文主要研究工作如下：首先,分析了一种无源无损三相PWM逆变器的拓扑结构,通过开关管的各个状态分析了此拓扑结构的工作原理和工作过程。建立起数学模型并求解了主要参数值。通过理论分析验证了此电路可以实现开关器件的软开关,并能实现能量的回馈,为后续的研究提供了理论基础。其次,通过分析此电路软开关的工作条件设计了SPWM的控制策略,只要调制度符合零电压开关和零电流开关的条件,就能实现开关管的软开关。随后对三相无源无损软开关逆变器进行了仿真研究,与传统的逆变器仿真结果进行了比较分析,并对此结构进行了频谱分析,通过仿真验证了控制策略的正确性。最后,指出了理论研究和实际应用中存在的问题,对下一步研究工作进行了展望。更多还原

【Abstract】 In recent years, with the development of PWM inverter, there have been radical changes on the design of power converter. It has been changed from heavy and enormous power frequency transformer to light and small density power converter, and the whole efficiency of converter has been greatly improved too. These changes will benefit the design and application of PWM inverter. However, with the rapid development of China’s industry and the increase of energy demand, highly effective energy-Saving inverter becomes the focus of research.Traditional inverter technology is mature, reliable, widely applied, but there are some disadvantages such as large on size, big audio noise, poor system dynamic characteristics, etc. Soft-switching technology is regarded as an advanced technology in the design of power inverter. In order to solve traditional snubber’s disadvantages of circuit loss, the lossless soft switching technology is proposed. Lossless soft switching technology can be separated into passive lossless soft switching technology and active lossless soft switching technology, depending on whether the active switch exists or not. Though active losses soft switching technology can reduce switching loss, the structure and the control are complex. Passive lossless soft switching technology just adds some passive components into converters to transfer and feedback energy to reach the lossless effect. While, passive lossless soft switching technology can not only reduce switching loss and noise, but also have simple circuit, low cost, and high reliability, so it receives widely focus and study in recent years.Soft switching inverter, which controls resonance process by auxiliary switching device, has complex control model and difficult implementation. So an absorption soft switching topology is studied in this thesis. It makes main switching device on under zero-current and off under zero-voltage. The characteristic of such circuit topology is that the upper and lower tubes of the bridge arm share the same reanalyzing absorption inductance and turn-off capacitance. On the basic of optimizing main absorption structure, a spot of inductance and diode elements are added, which realizes the minimization of additional elements. Furthermore, capacitance-structured voltage source makes energy feedback and the restoration of absorption elements come true.The thesis summarizes the improvement and present situation of soft switching inverter technology based on reading and studying on a lot of relevant literature. The main study works are as follows:Firstly, a passive lossless main circuit topology of three phase PWM inverter is analyzed. According to each state of switch tube, the thesis analyzes the working principle and working process of this topology, establishes mathematical model and solves the main parameters value. Based on the theory analysis, the thesis verifies that the circuit can realize soft-switching of switch device and realize energy feedback, thus provides a theoretical basis for subsequent studies.Secondly, the control strategy of PWM is designed through analyzing the soft switching working condition of this circuit. Only if modulation depth fits in with the condition of zero-voltage-switching and zero-current-switching, soft-switching of switch tube can be realized. A follow-up simulation study of three phase passive and lossless soft switching inverter is made. Comparing with the simulation result of traditional inverter and analyzing the stroboscope of the structure, the correctness of control strategy is verified.Finally, some existing problems in theoretical study and practical application are pointed out, and the prospect of research work of next step is presented in the thesis.更多还原