Power Electronic Control Of Motor Actuator Simulation Study Of The Institutional Dynamic Characteristics

As one of the important parts of a circuit breaker, the operating mechanism is required to guarantee long-term operational reliability of the circuit breaker as well as to be beneficial to arc extinction. Conventional operating mechanisms presents complexity in structure design and little flexibility in control, hence they normally cannot fulfill the requirement for a specific opening or closing operation in power systems and often pose high failure rates. In order to improve reliability, stability and security of power systems, investigations are continued to develop new operating mechanisms for circuit breakers.Presently, two kinds of operating mechanisms are being developed, one is based on permanent magnetic actuator together with electronic control, and the other is power electronics controlled motor drive mechanism. The motor drive mechanisms also can be divided into two types, i.e. rotary motor and direct-line motor drive types. Direct-line motor driven circuit breaker has been developed with relatively mature technology available; however, rotary motor driven circuit breaker is a new research area to be explored.With the development of power electronics and modern control theory, the advantages of rotary motor control are more and more evident. Therefore, rotary motor driven circuit breaker falls into researchers' vision with potential application perspective. A motor with flexible control capability can realize any kinds of closing and opening operations of a circuit breaker, providing arbitrary velocity-force characteristics under different working conditions. The motor driven circuit breaker has unique advantages in mechanical structure design and controlled operation time, and will be the developing direction of phase-controlled circuit breaker.The research of this thesis concentrates on the power electronics controlled motor driven mechanism. A feasible control strategy is proposed to realize smooth closing and opening operations of circuit breaker, and subsequently the possibility of using intelligent control is analyzed. Firstly, the advances in circuit breakers' operating...