Research And Design On Fm Series-Resonant Voltage Withstand Test System

The grid is moving towards a "one-three" direction. Now and in the future more and more high-voltage electrical equipment will be used in the power grid. After installation, many electrical equipment must be tested by AC voltage before using. The results determine whether these electrical equipment can put into operation correctly. Because the traditional power-frequency test transformer requires high voltage, large capacity power supply when it finish the voltage withstand test of high voltage equipment, which make the equipment very heavy and not suitable for field testing. So the FM series-resonant voltage withstand test appliance of using resonance principle have high practical value and very important significance. FM series-resonant voltage withstand test appliance as the core,which include few aspects.Firstly, the paper explained few basic types of serial resonance device. The advantages and disadvantages of several test were compared and analyzed, and the conclusion that the test method of frequency conversion series-resonant was the best way for voltage test of electrical equipment.Secondly, the principle, energy and frequency characteristic of FM serial resonance device was analyzed and discussed, which derived the finding of resonance point of test circuit. SPWM modulation mode was analyzed in detail and contrasted. The unipolar SPWM modulation was decided to change frequency and voltage of the variable frequency power supply.Inverter circuit was created model and analysised. The main circuit of pressure system was researched and designed,which includ main circuit design, choice of parameters of the test device. In particular, the low-pass filter for inverter circuit was designed in detail. Then open-loop was simulated to verify the correctness of design and feasibility.Voltage control mode of inverter circuit was researched. Through the parameters of single loop PID control, double-loop control about P/PI/PD/PID of the instantaneous of output voltage used pole assignment method to design and calculate. By comparison, this paper selected PI of voltage and P of current dual-loop control as control mode of PWM inverter. But the amplitude was not very good, so the mean outer ring was increased outside the double-loop PI control to control the output voltage, it was simulated by Simulink.Finally, the part of the software and hardware of the control system was designed. The methods, requirements of frequency conversion series-resonant voltage withstand test and the ready before test were explained in detail. And the pressure system in the resonant points was simulated by simulink.