【作者】 王强；

【导师】 张化光；

【作者基本信息】 东北大学 ， 控制理论与控制工程， 2010， 博士

【摘要】 本文围绕软开关PWM逆变器这个主题,在对三相软开关逆变器拓扑研究现状分析、评价的基础上,对新型的软开关三相PWM逆变器电路拓扑进行了深入的研究。本课题是国家高技术研究发展计划(863计划)重点项目资助的《电气传动及控制系统节能技术的研发》(课题编号：2006AA04Z183)中的一部分——软开关PWM逆变器的研究及应用。研究软开关三相PWM逆变器主电路拓扑结构及其控制策略,旨在探索一种控制简单、可靠性高的软开关三相PWM逆变器,为产业提供一种可行的软开关三相PWM逆变器方案,并将其应用到电气传动控制系统中。主要工作如下：1、提出了一种基于有源辅助换流的新型零电压零电流谐振极软开关PWM逆变器的拓扑结构,它是利用有源辅助开关器件来控制谐振过程,使主开关器件开通前电压先降到零,关断前电流先降到零,实现零电压开通和零电流关断,同时解决了容性开通损耗问题和拖尾电流造成的关断损耗问题。详细分析了该电路的工作原理,给出了参数设计方法,通过仿真和实验验证了该新型零电压零电流软开关电路的有效性。2、本文已经提出的三相零电压零电流软开关逆变器的拓扑结构中有6个辅助开关器件,为减少辅助开关器件的个数,简化控制方式和电路结构,提高可靠性,对已经提出的三相零电压零电流软开关逆变器的拓扑结构做了改进,提出了一种只有两个辅助开关器件的新型谐振直流环节软开关三相PWM逆变器,使主开关在零电压的条件下完成开通和关断。详细分析了该电路的工作原理和控制方式,给出了参数设计方法,通过仿真和实验验证了该新型谐振直流环节软开关电路的有效性。3、本文已经提出的两种软开关PWM逆变器虽然能有效地实现软开关,降低开关损耗,但是其拓扑结构中都需要设置有源辅助开关器件,导致控制复杂,附加成本较大,可靠性相对降低。为进一步简化三相软开关逆变器的控制方式,提高其可靠性,本文提出了一种新型三相无源软开关PWM逆变器的拓扑结构,其辅助谐振电路中没有辅助开关器件,控制简单,通过降低主开关开通瞬间的电流变化率和关断瞬间的电压变化率来减小开关损耗,实现了零电流开通和零电压关断；通过拓扑结构中的储能元件,在死区时间内,电路可以继续向负载供电,输出相电流可以续流,降低了死区的影响,减小了输出相电流在低频时的畸变率；直流母线之间串联了3个起均压作用的电解电容,分析了电解电容的电压偏差及其对输出电压和软开关的影响。探讨了在本电路拓扑下实现软开关动作的工作机理、实现软开关的条件,建立起了相应的控制策略,进行了仿真研究,并制作了1kW的实验样机来验证该软开关电路工作原理的正确性。4、对提出的新型三相无源软开关PWM逆变器的拓扑结构进行了改进,原拓扑结构中,三相辅助谐振电路共有一组谐振电感,这将会导致三相的谐振过程相互干扰,不能可靠地实现软开关,改进的结构中三相辅助谐振电路各有一组谐振电感,使三相的辅助谐振电路相互独立,提高了可靠性；另外对零电压关断的实现条件也进行了改进,改进后,通过选取合适的电感值就可以有效降低关断损耗,不需要为降低关断损耗去限制触发脉冲的最小宽度,通过仿真验证了以上改进的有效性,为将其应用到电气传动控制系统中奠定了基础。5、将改进后的新型三相无源软开关PWM逆变器的拓扑结构应用到了项目组自主研发的10kW电气传动控制系统中,简要介绍了该控制系统的组成和设计,对改进后的新型三相无源软开关PWM逆变器进行了实验研究,对实验结果进行了分析、总结,实验结论验证了本拓扑结构可以有效地在电气传动控制系统中起到节能作用。更多还原

【Abstract】 Based on the analysis and evaluation of current research status of soft-switching topology of three-phase inverter, the dissertation focused on the topic of soft-switching three-phase PWM inverter, and made further research on circuit topology of soft-switching three-phase PWM inverter. The research topic of the dissertation is one part project of The Research of Energy Saving Technology of Electrical Driven and Control System (Project NO. is2006AA04Z183) that is supported by National High Technology Development Plan. The purpose of research on the main circuit topology and control strategy of soft-switching three-phase PWM inverter is to explore a soft-switching three-phase PWM inverter with high reliability and simple control, to study its working system and provide a feasible scheme of soft-switching three-phase PWM inverter for industry and apply it in electric drive control system.The main research work is as follows:1. A novel zero-voltage and zero-current soft-switching PWM inverter topology circuit with active auxiliary commutation is proposed, in which auxiliary switches are employed to control the resonant process. Because the voltage across main switches decreases to zero before main switches are turned on and the current decreases to zero before main switches are turned off in the novel topology, zero-voltage turn-on and zero-current turn-off can be realized. The problems of turn-on capacitive losses and the tail current are both solved. The equivalent circuits at different operation modes, the analysis of the circuit and parameter design method are presented. Simulation and experimental results are proposed to verify the validity.2. Six auxiliary switches are needed in the zero-voltage and zero-current three-phase soft-switching topology circuit which has been proposed in the dissertation. In order to reduce number of auxiliary switches, simplify the circuit structure and control strategy, improve reliability, author has improved the three-phase zero-voltage and zero-current soft-switching topology circuit and proposed a novel three-phase resonant DC link soft-switching PWM inverter topology circuit which only includes two auxiliary switches. The equivalent circuits at different operation modes, the analysis of the circuit, the control strategy and parameter design method are presented. Simulation and experimental results are proposed to verify the validity of the proposed three-phase resonant DC link soft-switching PWM inverter topology.3. Although two soft-switching PWM inverters which have been proposed in the paper can effectively realize soft-switching and reduce loss, active auxiliary switches are needed in the two topologies, which can lead to complicated control strategy, additional cost and relatively poor reliability. In order to simplify control strategy and improve reliability further, a novel three-phase passive soft-switching PWM inverter topology is proposed to reduce di/dt during turn-on transient and du/dt during turn-off transient to reduce switching loss of main switches. Zero-current turn-on and zero-voltage turn-off can be realized. There are no auxiliary switches in the auxiliary resonant circuit and control method is simple. In the novel topology, freewheeling of output current can be realized via energy storage components in the dead-time and the effect of dead-time is reduced. The distortion ratio of the output phase current in low frequency is also reduced. Three DC-bus electrolytic capacitors are placed for voltage sharing. The influence of voltage deviation of electrolytic capacitors on output voltage and soft-switching is analyzed. The working principles on how to realize soft-switching via the proposed topology are discussed. Besides, the realization conditions and control strategy are also studied. Furthermore, the topology is studied by simulation. Finally, a lkW experimental prototype is made to verify the validity of the proposed topology.4. The novel three-phase passive soft-switching topology is improved. There is only one common group of resonant inductors in three-phase resonant circuit of the original topology, which leads to mutual influence in resonant process and poor reliability; there are three groups of resonant inductors corresponding to three-phase resonant circuit of improved topology, so resonant process of every phase is independent, which enhances reliability. In addition, the realization condition of zero-voltage turn-off is also improved. By designing proper inductance parameters, loss during turn-off transient could also be reduced without the restriction of minimum width of trigger pulse. Simulation results verify the validity of the above improvement and establish foundation for application in electric drive control system.5. The improved three-phase passive soft-switching topology is applied in the10kW electric drive control system which is researched independently by project team. The composition and design of the system is described in brief. The improved three-phase passive soft-switching topology is experimentally studied. Experimental results show energy saving effectiveness of the improved three-phase passive soft-switching topology which is applied in electric drive control system.更多还原