With soft - switching technology , inverter spot - welding power source has lower switching dissipation , lower electromagnetic interference and lower sensitivity to parasitic parameters of power circuit , contribute to inverter output characteristics and circuit efficiency , stability and reliability 采用软开关技术的点焊逆变电源，可减小开关损耗、电磁干扰及对电路寄生参数的敏感性，并从根本上改善电路的输出特性，提高电路的效率、稳定性和可靠性。
Switching loss and efficiency of the proposed resonant pole zvt three - phase pwm inverter are analyzed and discussed . results of calculation and testing of the prototype together with a hard - switching inverter with the same specification show that an improvement of 2 % ~ 3 % is obtained . based on the analysis of drawbacks of existing svpwm technique in resonant pole zvt three - phase pwm inverters , several improved svpwm methods are presented 对提出的谐振极零电压过渡三相pwm逆变器的开关损耗和工作效率，进行了深入的分析和讨论，并针对原理样机进行了理论计算和实际测量，并与相同规格的硬开关三相逆变器进行了对比研究，结果表明，采用提出的软开关技术的原理样机的效率可以提高2 % 3 。
The dissertation takes the pmsm ( permanent magnet synchronous motor ) ac servo drive system as research object , according to the requirement of developing high performance pmsm ac servo drive system , and combing the new development of control theories and soft - switching technology . on the basis of analysis and research of theory , a full digital pmsm ac servo drive system based on soft - switching technology is developed , with the dsp ( tms320f2812 ) and cpld ( epf10k10lc84 - 15 ) as the central control unit 本文以极具发展前景的pmsm交流伺服驱动系统为研究对象，在综合分析现代交流伺服系统发展趋势和借鉴前人研究成果的基础上，针对发展高性能pmsm交流伺服驱动系统的需要并结合控制理论和软开关技术的新发展，在理论研究的基础上，设计实现了一套完整的基于软开关技术并应用dsp ( tms320f2812 )和cpld ( epf10k10lc84 - 15 )为控制核心的全数字化pmsm交流伺服驱动系统。
Wuxi , nov 18 , 2007 - - on november 18 , 2007 , siemens medium voltage switching technologies ( wuxi ) ltd . ( smvs ) celebrates its 10th anniversary , together with the successful application of siemens world - leading 25 - years of gis ( gas insulated switchgear ) and 35 years of vi ( vacuum interrupter ) technology 无锡11月18日消息? 2007年11月18日，西门子中压开关技术(无锡)有限公司庆祝公司成立十周年，以及西门子全球领先的气体绝缘开关( gis )和真空灭弧室( vi )技术也分别迎来了成功应用25周年和35周年。
A topology of asymmetrical half bridge soft switching is researched in this thesis , which has inherent zero voltage switching ( zvs ) capability and thus potentially higher efficiency by its resonating of the leakage of power transformer with the parasitic capacitances of the power mosft switches , whereas it does n ' t raise the expense of the converter these studies in the thesis have been done as follows : ( 1 ) the topology of asymmetrical half bridge is introduced , and its principle and the relation of duty cycle and input voltage and output voltage discussed , the method of eliminating the deflection magnetism is also brought forward 虽然，软开关技术能够实现功率变换器的小型化、模块化等，但是，电路变得更加复杂，使得中小功率的变换器的成本增加，往往不利于商业竞争。本文研究了一种零电压的不对称半桥拓扑结构，它可以在不增加电路成本的基础上，利用电路自身的特点，实现软开关。本文所做的主要工作如下： ( 1 )对不对称半桥主电路工作原理进行分析，给出了占空比与输出电压、输入电压的关系以及消除变压器偏磁的方法。
In this thesis , we mainly investigate the resonant soft switching pwm inverter . the main contents are as follows : 1 . through analysis of the dc - rail resonant soft swithing inverter and zvt ( zct ) - pwm technique , we advance the solution to resolve the question - how to apply pwm technique to control dc - rail resonant soft swithing inverter is resonant transition technique 主要内容为：对直流环节谐振型逆变器的现状进行分析研究，针对如何把谐振软开关技术和pwm技术结合起来这一关键问题，提出解决这一问题有效的办法是谐振过渡技术。
