串级调速毕业设计论文.doc

串级调速毕业设计论文 摘 要 串级调速系统是在转子回路中串入附加电动势，以改变转差率来实现调速。串入附加电动势而增加的转差功率，回馈给电网或者回馈到电动机轴上使系统有较高的运行效率。它能实现无级平滑调速，低速时机械特性也比较硬。特别是晶闸管低同步串级调速系统，技术难度小，性能比较完善The cascade velocity modulation system is the string enters the additional EMF in the rotor return route, changes the sliding to realize the velocity modulation.The string enters slips the power which the additional EMF increases, the back coupling for the electrical network or the back coupling to the electrically operated engine shaft on enable the system to have the high operating efficiency. It can realize the stepless smooth velocity modulation, when the low speed the physical characteristics quite is also hard. The thyristor low synchronization cascade velocity modulation system, the technical difficulty is specially small, the performance quite is perfect. This design introduced one kind of double closed-loop control cascade velocity modulation system, to the system principle of work, the composition and the dynamic structure has made a more detailed elaboration, has analyzed time the exchange cascade velocity modulation system work main characteristic, according to the above and has made the general qualitative analysis to it with the normal wiring or time the rotor return route string resistance velocity modulation efficiency and compares. Lowers this main shortcoming in view of the traditional cascade velocity modulation system total output factor, analyzed one kind of rotor side to add the shorting contact switch the cascade governing system. Because the rotor side adds the shorting contact switch the cascade velocity modulation system to be able fully to use the electrical machinery nature active status power factor high characteristic, when belt permanent torque loading the power factor has certain degree enhancement. This design report first the basis design request determination velocity modulation plan and the main circuit structure pattern, after the main circuit and the closed-loop system determine, t