In chapter four , the software design of dsp control system for active power filter is presented . the main program flow chart , harmonic current detecting method , soft start , and dc bar voltage control are introduced detailed 讨论了谐波与无功指令电流的计算、软起动以及直流侧电压控制与均压控制的设计，并讨论了数字控制对补偿精度的影响。
Then the author gives the primary circuit and its protect circuit design method of the fcl , and obtains primary circuit parameters of an fcl test prototype ( 380v / 200a ) and an fcl industry prototype ( 10kv / 500a ) by this means 第三章给出了固态限流器主电路元件参数的计算方法，包括限流电感设计、旁路电感计算、桥电路及其均压保护电路设计等。
To reduce voltage stress of transformer secondly diodes , a novel parallel - parallel / serial type cttfc is presnt . it has many attractive characteristics , such as low current stress of power switches , small intput and output filter size , high reliability , and sharing output voltage 提出了一种并?并串型双管正激组合变换器，该组合变换器具有副边二极管电压应力低、开关管电流应力小、输出均压、输入输出滤波器体积小等优点。
According to the investigation of the rule of air flow at the stope , and applying the technical method of the equal press fire prevention and pouring sand plasma , the author analyzed the feasibility of the exploitation under the fire area , and demonstrated it with examples 通过对采场风流流动规律的研究，找出火区漏风源和漏风汇；应用均压防火和注浆堵漏技术措施，对火区下开采技术的可行性进行了系统分析，并举出成功实例加以论证。
Also the small signal model of tdfc is established , furthermore , which is verified by the frequency characteristic of tdfc measured by hp4195a network / spectrum analyzer . final a control method is designed for the tdfc . and the method to measure the frequency characteristic is discussed too 推导了变换器的小信号模型，并用网络频谱分析仪测出占空比对输出电压和占空比对分压电容均压误差的频率响应特性，并进行理论模型和实验模型的比较研究。
To reduce voltage stress of power switches , a series - parallel type cttfc is studied in this paper . voltage - sharing of input capacitors can be realized naturally in discontinuous conduction mode , andvoltage - sharing of input capacitors can also be realized naturally in continuous conduction mode . the voltage stress of power switches is only half of the input voltage , so power mosfet can be used in high input voltage applications 揭示了串?并型双管组合变换器电流断续工作方式时输入电容电压自然均压的机理；对于电流连续工作方式，也能实现输入电容自然均压。输出续流管串联方式的串?串型双管正激组合变换器，其输入电容自然均压特性与串?并型双管正激组合变换器一致。
Finally the high voltage thyristor vale was tested in lab . the results illuminate the good insulation structure , reliable triggering and blocking , good voltage division on each thyristor , and that the bod protecting circuit acts rapidly . in a word the high voltage thyristor vale satisfies the expected specification in the application of auto - passing over neutral section of traction power supply system 最后论文对高压晶闸管阀在实验室进行的各种试验进行了分析总结，试验结果表明，该高压晶闸管阀绝缘结构合理，触发和关断可靠，元件在各种工况下的均压一致性良好，过压保护电路动作迅速，达到了在牵引供电网自动过分相装置应用中的技术要求。
All sorts of imperceptible factors making the system get worse , including the harmonic of the inverter and magnifying of dv / dt over long cable and the effects after applying the inverter . i applied the three - level main circuit structure to the esp system , so that the high voltage problems resulted by low endureing voltage can be solved , at the same time avoided the voltage distributing because of devices in series 为此本文将三电平主电路结构运用到潜油电泵变频系统中，以解决由于当前器件耐压较低而要求实现中高压问题，同时避免了由于器件串联而引起的均压问题，具有谐波含量较二电平变频器要低和体积较低压单元串联方式要小等特点。
