Abnormal voltages such as electrostatic,constant current,and strong electromagnetic signals can erroneously trigger operation of MEMS pyrotechnics and control systems in a fuze,which may result in casualties.This stud...Abnormal voltages such as electrostatic,constant current,and strong electromagnetic signals can erroneously trigger operation of MEMS pyrotechnics and control systems in a fuze,which may result in casualties.This study designs a solid-state micro-scale switch by combining the corona gas discharge theory of asymmetric electric fields and Peek’s Law.The MEMS switch can be transferred from“off”to“on”through the gas breakdown between the corona electrodes.In the model,one of the two electrodes is spherical and the other flat,so a non-uniform electric field is formed around the electrodes.The theoretical work is as follows.First,the relation among the radius of curvature of the spherical electrode,the discharge gap,and the air breakdown voltage is obtained;to meet the low voltage(30-60 V)required to drive the MEMS switch,the radius of curvature of the spherical electrode needs to be 10 e50 mm and the discharge gap between the two electrodes needs to be 9e11 mm.Second,the optimal ratioεis introduced to parameterize the model.Finally,the corona discharge structural parameters are determined by comparing the theoretical and electric field simulation results.The switch is then fabricated via MEMS processing.A hardware test platform is built and the performing chip tested.It is found that when the electrode gap is 9 mm,the electrostatic voltage is at least 37.3 V,with an error of 2.6%between the actual and theoretical air breakdown voltages.When the electrode gap is 11 mm,the electrostatic voltage is at least 42.3 V,with an error of 10.5%between the actual and theoretical air breakdown voltages.Both cases meet the design requirements.展开更多
Partial discharge(PD) is one of the most important phenomenon in high voltage insulations.In most cases, the appearance of partial discharges is related to insulation defects.Understanding partial discharges is import...Partial discharge(PD) is one of the most important phenomenon in high voltage insulations.In most cases, the appearance of partial discharges is related to insulation defects.Understanding partial discharges is important for diagnosis on insulation condition.Corona discharges appear when extremely high electric field appears on the conductor surface exceeding the electric field strength of the gas.The high electric field may occur at around protrusion with very sharp tip.This paper reported a holistic approach of corona discharge investigation.The needle-plane electrode system was used.The medium between the electrodes was air.The needle was made from steel with radius of curvature of 3μm(Ogura needle).Sinusoidal as well as triangular applied voltages were used.The waveform of the corona discharges was measured using a digital oscilloscope.The corona discharge pulses were measured using a phase-resolved PD measurement system.The system was able to measure the magnitude(q) and phase angle position(φ) of each PD pulses,as well as the number of discharge pulses(n).The role of applied voltage was investigated using phase-resolved analysis of corona discharge pulses through pulse sequence,pulse magnitude and pulse number analysis. Experimental results indicated that corona discharge current waveform was an impulse with rise time of about several ns and the impulse width of about 100 ns.The Fast Fourier Transform analysis indicated that the corona discharge current waveform had several spectrum peaks at frequency of 7.8 MHz,85.9 MHz,109.4 MHz and 195.3 MHz.The experimental results also showed that discharge pulses were concentrated around the peak of applied voltage for both sinusoidal and triangular voltages.The discharge magnitude,as well as its probability of occurrence,was strongly dependent on the instantaneous applied voltage.The shape ofφ-n,as well asφ-q-n PD patterns,were strongly reflected by the shape of applied voltage.In order to get deep understanding of the corona discharge,by utilizing results of the phase-resolved analysis,electrical equivalent circuits of corona discharges were proposed.The electrical equivalent circuit contained capacitances and a spark gap.For deeply understanding of PD phenomenon,computer simulation was done by using the proposed electrical equivalent circuits.The similarity of the measured and simulated PD patterns was assessed by comparing measured and simulated theφ-q-n andφ-n PD patterns.The results indicated that simulated PD patterns similar to those obtained from experiment.展开更多
文摘Abnormal voltages such as electrostatic,constant current,and strong electromagnetic signals can erroneously trigger operation of MEMS pyrotechnics and control systems in a fuze,which may result in casualties.This study designs a solid-state micro-scale switch by combining the corona gas discharge theory of asymmetric electric fields and Peek’s Law.The MEMS switch can be transferred from“off”to“on”through the gas breakdown between the corona electrodes.In the model,one of the two electrodes is spherical and the other flat,so a non-uniform electric field is formed around the electrodes.The theoretical work is as follows.First,the relation among the radius of curvature of the spherical electrode,the discharge gap,and the air breakdown voltage is obtained;to meet the low voltage(30-60 V)required to drive the MEMS switch,the radius of curvature of the spherical electrode needs to be 10 e50 mm and the discharge gap between the two electrodes needs to be 9e11 mm.Second,the optimal ratioεis introduced to parameterize the model.Finally,the corona discharge structural parameters are determined by comparing the theoretical and electric field simulation results.The switch is then fabricated via MEMS processing.A hardware test platform is built and the performing chip tested.It is found that when the electrode gap is 9 mm,the electrostatic voltage is at least 37.3 V,with an error of 2.6%between the actual and theoretical air breakdown voltages.When the electrode gap is 11 mm,the electrostatic voltage is at least 42.3 V,with an error of 10.5%between the actual and theoretical air breakdown voltages.Both cases meet the design requirements.
文摘Partial discharge(PD) is one of the most important phenomenon in high voltage insulations.In most cases, the appearance of partial discharges is related to insulation defects.Understanding partial discharges is important for diagnosis on insulation condition.Corona discharges appear when extremely high electric field appears on the conductor surface exceeding the electric field strength of the gas.The high electric field may occur at around protrusion with very sharp tip.This paper reported a holistic approach of corona discharge investigation.The needle-plane electrode system was used.The medium between the electrodes was air.The needle was made from steel with radius of curvature of 3μm(Ogura needle).Sinusoidal as well as triangular applied voltages were used.The waveform of the corona discharges was measured using a digital oscilloscope.The corona discharge pulses were measured using a phase-resolved PD measurement system.The system was able to measure the magnitude(q) and phase angle position(φ) of each PD pulses,as well as the number of discharge pulses(n).The role of applied voltage was investigated using phase-resolved analysis of corona discharge pulses through pulse sequence,pulse magnitude and pulse number analysis. Experimental results indicated that corona discharge current waveform was an impulse with rise time of about several ns and the impulse width of about 100 ns.The Fast Fourier Transform analysis indicated that the corona discharge current waveform had several spectrum peaks at frequency of 7.8 MHz,85.9 MHz,109.4 MHz and 195.3 MHz.The experimental results also showed that discharge pulses were concentrated around the peak of applied voltage for both sinusoidal and triangular voltages.The discharge magnitude,as well as its probability of occurrence,was strongly dependent on the instantaneous applied voltage.The shape ofφ-n,as well asφ-q-n PD patterns,were strongly reflected by the shape of applied voltage.In order to get deep understanding of the corona discharge,by utilizing results of the phase-resolved analysis,electrical equivalent circuits of corona discharges were proposed.The electrical equivalent circuit contained capacitances and a spark gap.For deeply understanding of PD phenomenon,computer simulation was done by using the proposed electrical equivalent circuits.The similarity of the measured and simulated PD patterns was assessed by comparing measured and simulated theφ-q-n andφ-n PD patterns.The results indicated that simulated PD patterns similar to those obtained from experiment.
