Design And Research On A New Hybrid Intelligent Circuit Breaker For DC-Application

DC power systems have been increasingly applied and developed in fields such as renewable clean energy power generation,ships,and rail transit.As a key protection devices in DC power grids,researching fast and effective DC circuit breakers is of great significance in preventing the extension of faults.The extensive application of computer and network communication technology has promoted the rapid development of intelligent controllers,it has also increased the degree of automation and intelligence of circuit breakers.Based on traditional circuit breakers,designing intelligent DC circuit breakers with automation,intelligence,modularity,and more protection functions has practical engineering value.This paper compares and analyzes the research status of many types of DC circuit breakers at home and abroad,and proposes a new hybrid DC circuit breaker main circuit structure based on high-power power electronic devices and vacuum high-speed switches.The PIC microcontroller(Peripheral Interface Controller)and CPLD(Complex Programmable Logic Device)are used as the control core.The CAN(Contoller Area Network)bus communication is used to transfer data with the host computer,and an ARM chip is used to process data such as CAN communication and fault information to construct an overall design plan of the intelligent controller.Firstly,a new type of main circuit design scheme for DC circuit breakers is given.This scheme adopts a hybrid structure and forced commutation ideas,then presents the principle analysis and design of shutdown circuit,main switch and energy-absorbing voltage limiting branch.Then according to the modular design concept,the working principle and design scheme of the main functional modules of the controller are introduced in detail.The hardware circuit composed of CPLD and high-speed comparator is used to deal with the short circuit fault.Hardware and software consisting of PIC microcontroller and CPLD are used together to deal with other faults such as overload,and AD7606 is used to realize high-precision external AD sampling,Communication with the host computer via CAN bus communication,storage of fault information with ferroelectric memory,processing circuit fault information and CAN communication information with the ARM chip,and then exchange data with the PIC microcontroller.Complete the design of the control module,communication module and related hardware circuits.Based on the study of protection,measurement methods and implementation principles,the modular design of the software and the preparation of the host computer monitoring interface were performed to satisfy the circuit breaker.And effective anti-jamming measures have been adopted in hardware and software design to improve the anti-jamming ability of the controller and ensure the reliability of the circuit breaker.Finally,the prototype of the circuit breaker was built.Short-circuit fault simulation experiments were conducted after the completion of the test.The experimental results met the requirements of the design index and verified the feasibility of the scheme.