Design And Experimental Study Of A Bridge DC-chopper Experimental System For High Temperature SMES

With the continuous development of the high temperature superconducting fields,great progress has been made in the new-type superconducting energy storagetechnologies. Various kinds of advanced superconducting energy storage devices havebeen developed consecutively and applied profoundly to solve the power system faults,such as voltage drop, power interrupt and low frequency oscillation, thus verifying itsfeasibility and practicability from the theory analysis and practical applications.Working principle of the high temperature superconducting (HTS) coil is discussedin this thesis, then an innovation and exploratory study is carried on about thebridge-chopper of superconducting magnetic energy storage (SMES) devices based onthorough analysis of the charging and discharging characteristics. The thesis mainlyincludes:1. The key technologies of SMES devices are researched and analyzed accordingto the existing experimental apparatus, and a new bridge-chopper circuit is proposedbased on the conventional four quadrant topology with its advantages of higher energystorage efficiency verified by simulation calculation and experimental analysis.2. The charging and discharging characteristics of the HTS coil are theoreticalanalysed, then a digital control method is proposed based on model analysis and theHTS coil’s operation states are simplified into several binary numerical combinations toform a digital process flow chart, thus obtaining an efficient and convenient control forSMES systems.3. The actual building technologies of bridge-chopper are analyzed, and a practicalHTS control system is designed with its hardware and software section elaborated basedon the proposed control method and combinations of a single-chip microcomputer(SCM) and a complex programmable logic device (CPLD), thus verifying its feasibilityby theory analysis and experimental study.4. The charging and discharging characteristics of the HTS coil are experimentalstudied, and the performance influences under different system parameters to thecharacteristics are expounded. A much higher energy storage efficiency of the bridge-chopper circuit is veried by experimental comparative analysis with theconventional one.The magnetic energy exchange process is analyzed by changing the rated currentand load power and the superiority of the bridge type chopper is researched andanalyzed compared with the traditional one, thus providing the necessary experimentalbasis and reference value for incorporating into the power system.