The Design And Development Of Control Sysrem For Solid State Transfer Switch

With the development of economicly social and the progress of technologyscience, the demand for electricity continues to grow. The demand of quality forpower supply is increasing at the same time.Especially in the field of industrial,voltage dip causes huge losses by production disruptions and damage to theequipment. A solid state transfer switch of the control unit on DSP and power unit onthyristor is designed.The device can switch between two power supplies quickly andthe switching time was less of4ms.It meetes the requirements of the most sensitiveequipment on the quality of power supply,also a good solution for voltage sags.Firstly,more than98%of quality of power supply problems are voltage dips.Thispaper applicates solid state transfer switch device to solve the problem of voltagesags after analysed the solutions for voltage sags at home and abroad.Secondly, an important performance indicators of the solid state tranfer switch isswitching time and an important factor affecting the switching time is voltage sagdetection time. Therefore,the choice of the voltage sag detection method isparticularly important.The method of the detecting voltage sag is loss,for exampleFourier transform, wavelet transform and artificial neural network algorithm.Thefinal choice is abc to dqtransformation based on instantaneous reactive powertheory.D-q transformation is the three-phase voltage signal or virtual three-phasevoltage signal to a rms signal through the coordinate transformation and conversion.Itdetecting the voltage sag quickly by monitoring the RMSThirdly, the overall design of the solid state transfer switch is designedaccording to requirements of the basic functions and the overall framework designedaccording to the working principle of solid state transfer switchFourthly, hardware for control system of the solid state transfer switch device isdesigned and developed by the overall framework. The control system includes a dataacquisition module, data processing module and thyristor detection unit. The maintask of the data acquisition module is data acquisition and signal conditioning. Dataprocessing module receives the data acquisition module operations and issued theinstruction of switching control thyristor detection circuit for switching controlconditions, to ensure the safe operation of system. The software of control system isdesigned on the basis of DSP development environment CCS. Reading voltage signalparameters and calculation processing, the forced switching control program design and software of the CAN communication unit are designedFinally, the transfer time of the prototype device is tested.The test results showthat transfer time is less than4ms in pure resistive load or complex load and therequirements are meeted.