Solid-State High-Voltage Pulse Generator for Low Temperature Plasma Ion Mobility Spectrometry

Low-temperature plasma ion mobility spectrometry (LTP-IMS) is the method to identify some materials by measuring concentration of gas phase ions. IMS used in a wide range of laboratory-based biomedical research studies. A nanosecond pulse generator is necessary for LTP-IMS apparatus to enable direct analysis of various chemical compounds without having to evaporate the analyte or seek a solvent or any reagent. In this paper, a dual Marx pulsed generator for LTP-IMS Ionization power supply is proposed based on a new combination of some solid-state switches including insulated gate bipolar transistor (IGBT) and avalanche bipolar junction transistors (BJTs). The compact dual Marx generator is composed of a series of avalanche BJTs and an IGBT as the trigger switch, where its rise time is reduced from 100 to 5 ns by using an avalanche BJT in its command circuit. In this way, a controllable high-voltage pulse generator has designed, built, and tested. The proposed circuit can be used to generate the repetitive high-voltage pulses necessary for low temperature ionization in advanced IMS apparatus. The output voltage has an amplitude of up to 6 kV with pulse widths in the range of 40-1000 ns and pulse repetition rates up to 2 kHz, having rise time and fall time less than 10 ns independent of the load specifications

Optimized High Frequency Lumped Parameters Model of Induction Motor Using Genetic Algorithm (GA)

Abstract: In this paper an optimized high frequency lumped model of Induction motor is presented. Model parameters are identified and optimized using Genetic Algorithm (GA). A novel model and approach in an improved high frequency based on GA for parameter identification are used. At first, parameters are limited and then fitted using GA for best fitting. The proposed model considered accurate simulation of both differential and common mode behavior in the EMI-frequency range from 100 Hz to 30MHz. Model parameters which extracted from GA are compared with experimental data in both magnitude and phase at the same time and results show a good accordance between the experimental results and simulation results of the proposed model. A least mean square (LMS) method was used with a GA optimization method to solve the identification problem. The proposed model is suitable to obtain the simulation models to predict high frequency conducted Electromagnetic Interference (EMI), over voltage on terminated motor and common mode current in cable fed induction motor

Impact of Surface Morphology on Arcing Induced Erosion of CuW Contacts in Gas Circuit Breakers

In this paper, the impact of surface morphology of contacts, in particular different microstructural parameters like size and distribution of contact ingredients, on contact erosion in high voltage gas circuit breaker is investigated. It is demonstrated that the size and contiguity of copper and tungsten zones play a key role in contact erosion so that the mass loss in one specific contact after interruption of the rated short-circuit current is 2.5 times higher than that of another one, with the same dimensions and material composition. It is shown that the arc roots tend to be formed on larger copper zones and if the zones are not confined by tungsten area, the arc cross section expands resulting in a higher evaporation rate of copper areas. In addition, it is emphasized that ejection of tungsten particles after evaporation of surrounding copper areas is another mechanism leading to more contact erosion, which has to be taken into consideration in contact erosion modeling along with molten contact splash and vaporization

Online Assessment of Contact Erosion in High Voltage Gas Circuit Breakers based on different Physical Quantities

In this paper, an effort has been made to evaluate the online condition of arc contacts as a vital component of interruption chamber in high voltage puffer type SF6 circuit breakers. The relationship between eroded mass caused by short-circuit current interruption and different thermal stress indices such as transferred electrical charge, current squared, and arc energy is investigated, by performing many experiments with different current amplitudes and arcing times. It is demonstrated that none of the known indices can solely determine mass erosion caused by the current interruption. Therefore, the equations including two of defined parameters are proposed to evaluate mass erosion. The method using arc energy and transferred electrical charge owns the highest accuracy in evaluating mass loss. However, considering the complexity of arc voltage measurements, a second method using current and arcing time can be also utilized. In addition, the development of erosion during the lifetime of arc contacts is studied. It is shown that arc roots tend to form on new uneroded areas of the contacts during current interruption, resulting in different erosion rates between the first few and subsequent interruptions due to change of morphology of the contacts after the first few switching operations

Online Assessment of Contact Erosion in High Voltage Gas Circuit Breakers based on different Physical Quantities

In this paper, an effort has been made to evaluate the online condition of arc contacts as a vital component of interruption chamber in high voltage puffer type SF6 circuit breakers. The relationship between eroded mass caused by shortcircuit current interruption and different thermal stress indices such as transferred electrical charge, current squared, and arc energy is investigated, by performing many experiments with different current amplitudes and arcing times. It is demonstrated that none of the known indices can solely determine mass erosion caused by the current interruption. Therefore, the equations including two of defined parameters are proposed to evaluate mass erosion. The method using arc energy and transferred electrical charge owns the highest accuracy in evaluating mass loss. However, considering the complexity of arc voltage measurements, a second method using current and arcing time can be also utilized. In addition, the development of erosion during the lifetime of arc contacts is studied. It is shown that arc roots tend to form on new uneroded areas of the contacts during current interruption, resulting in different erosion rates between the first few and subsequent interruptions due to change of morphology of the contacts after the first few switching operations