Research On Key Technology Of High Voltage Pulse Capacitor Charge And Discharge Test Equipment

Pulse capacitors are the commonest and the most generally used energy storage components in pulse power technology,and are the important part of many pulse discharge devices.In practical engineering applications,pulse power technology often needs to work at a certain repetition frequency,that is,it needs to repeatedly charge and discharge the pulse capacitor.At this time,there will be a large electric power damage and energy loss inside the capacitor,which leads to the life of the capacitor.Reduce or even breakdown.Therefore,it is important to study the charge and discharge life of pulse capacitors at repetitive frequencies.According to the technical requirements of the high-voltage pulse capacitor charging and discharging test device,the overall structure of the whole test device is determined,including the high-voltage constant current charging power supply,the discharge circuit,and the measurement and control part.Detailed technical solutions had been analyzed and designed for each part of the test device.The three capacitor charging methods of constant voltage,power frequency constant current and high frequency constant current are compared.The three working modes of LC series resonance are analyzed and compared,and the current interrupt mode(DCM)is selected as the final charging mode.The high voltage constant current charging power supply is designed,including the following parts: rectification and filtering unit,high frequency transformer,series resonant inverter unit,high voltage rectifying silicon reactor.The parameter design and device selection of the above parts were carried out,and the charging process of the whole charging power supply was simulated and verified,and the "equal step" charging with the charging time of 5 seconds and the maximum charging voltage of 15 kV was realized.Based on the second-order circuit of RLC,the functional relationship between the specific technical requirements of the charge and discharge life test of high-voltage pulse capacitors and the components of the RLC circuit is derived,and the charging and discharging life of a series of pulse capacitors with typical capacitance is based on this.The measured inductance and resistance of the test were calculated,and the design results were simulated and verified by large-scale computer simulation software.The key component of the test device—high-voltage,large-capacity,AC discharge switch is designed.The high-voltage thyristor anti-parallel diode is used as the basic switching unit.According to the test voltage and the maximum discharge current of the device,the high-voltage,large-capacity,AC discharge switch in the device is realized by series and parallel connection of the basic switch unit.The problem of voltage non-uniformity and current imbalance in the process of series and parallel connection of basic switching units is analyzed,and the specific technical measures of equalizing and current sharing are proposed.Finally,a high-voltage,large-capacity,AC discharge switch technology scheme consisting of four switching units connected in series to form a single switching branch and three switching branches in parallel was designed.The main components were selected and the equalizing resistor was determined to meet the requirements—Maximum voltage 15 kV,maximum discharge peak current 130 kA,and leave a certain margin.The measuring methods of the voltage and current signals are determined.The voltage signal is selected by a resistor divider,and the voltage division ratio is 3000:1.The pulse high current signal is selected by the Rogowski coil for sampling.The IGBT drive circuit,the thyristor trigger circuit,and other secondary control loops are also designed.