scholarly journals The resistive ground fault of PWM voltage inverter in the EV charging station

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Zurek-Mortka ◽  
Jerzy R. Szymanski
Keyword(s):  
Power Supply ◽  
Common Mode ◽  
Voltage Inverter ◽  
Frequency Converters ◽  
Charging Station ◽  
Ground Fault ◽  
A Value ◽  
Ground Current ◽  
Voltage Frequency ◽  
Flow Through

AbstractDuring the direct touch of the inverter output voltage or with the ungrounded shield of the cable connecting the inverter to the motor or other type of load, the nonsinusoidal ground currents with a basic harmonic frequency between 1.5 and 16 kHz, flow via a human’s body. Here was proved that Residual Current Device (RCD) ($$I_{\triangle n}$$ I ▵ n = 30 mA) does not switch off the power supply when a ground current with a value of about some hundred milliamps occurs. Because RCDs do not disconnect the power supply, the touch on the inverter’s voltage is dangerous to health and life. For the authors, the RCD usage in the Voltage Frequency Converters (VFCs) is not a good engineer practice when high-frequency common-mode distortion currents flow through it. The paper presents tests of RCD operation in the event of a resistance ground fault (via human body) during EV battery charging where the PWM voltage inverter is connected to the external rectifier to provide DC charging battery voltage. Finally, the authors propose a method of eliminating common-mode (CM) current from short protection system by using a separate circuit in which the parasitic leakage current omits an RCD.

scholarly journals The Resistive Ground Fault of PWM Voltage Inverter In The EV Charging Station

2021 ◽  
Author(s):  
Marta Zurek-Mortka ◽  
Jerzy Ryszard Szymański
Keyword(s):  
Power Supply ◽  
Harmonic Frequency ◽  
Frequency Converters ◽  
Charging Station ◽  
Ground Fault ◽  
A Value ◽  
Ground Current ◽  
Voltage Frequency ◽  
Ev Charging ◽  
Current Device

Abstract During the direct touch of the inverter output voltage, the nonsinusoidal ground currents with a basic harmonic frequency between 1.5 kHz and 16 kHz, flow via a human’s body. Here was proved that Residual Current Device (RCD) type AC/IΔn = 30 mA does not switch off the power supply when a ground current with a value of about some hundred milliamps occurs. Because RCDs do not disconnect the power supply, the touch on the inverter’s voltage is dangerous to the health and life. For the authors, RCD usage in Voltage Frequency Converters is not a good engineer practice. The article presents tests of RCD operation in the event of a ground fault during EV battery charging.

Research on Capacitance Current Treatment Methods in Mine High-Voltage Power Grid

2012 ◽  
Vol 229-231 ◽  
pp. 1021-1024
Author(s):  
Dan Xu ◽  
Na Guo
Keyword(s):  
Coal Mine ◽  
Power Supply ◽  
Single Phase ◽  
Current Treatment ◽  
Automatic Tracking ◽  
Ground Fault ◽  
Arc Suppression Coil ◽  
Testing Data ◽  
Ground Current ◽  
Capacitance Current

In view of the coal mine neutral point ungrounded system when single-phase ground fault occurs, the grounding capacitance current is too big affect the security of coal mine powe supply.The paper analyzed testing data of capacitance current of coal mine network, established a treating scheme of capacitance current according to evaluating results, namely automatic tracking compensation arc suppression coil devices. The running results show that the scheme limits the size of the ground current and decreases rate of accidents of arc grounding over-voltage, which is good for improving the power supply safety.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Stochastic Model of Non-Isothermal Flow Chemical Reactor

1996 ◽  
Vol 61 (2) ◽  
pp. 242-258 ◽  
Author(s):  
Vladimír Kudrna ◽  
Libor Vejmola ◽  
Pavel Hasal
Keyword(s):  
Stochastic Model ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Dispersion Model ◽  
Chemical Reactor ◽  
Segregation Index ◽  
One Dimensional ◽  
A Value ◽  
Isothermal Case ◽  
Flow Through

Recently developed stochastic model of a one-dimensional flow-through chemical reactor is extended in this paper also to the non-isothermal case. The model enables the evaluation of concentration and temperature profiles along the reactor. The results are compared with the commonly used one-dimensional dispersion model with Danckwerts' boundary conditions. The stochastic model also enables to evaluate a value of the segregation index.

Micro-flowcell conductometric sweat analysis for cystic fibrosis diagnosis

2000 ◽  
Vol 37 (3) ◽  
pp. 399-407 ◽  
Author(s):  
H Lewis Webster ◽  
Carmelo G Quirante
Keyword(s):  
Power Supply ◽  
Time Interval ◽  
Sweating Rate ◽  
Sensor Cell ◽  
Sweat Testing ◽  
Small Holders ◽  
Flow Through ◽  
To Receive ◽  
Conductivity Cell ◽  
Sweat Tests

This paper describes a device specifically designed to facilitate neonatal sweat testing. The components are sized appropriately for attachment to the limbs of newborns. Iontophoretic electrodes, with pilocarpine gel inserts, are latched into small holders attached by straps to the limb. The holder at the anodic site remains in place to receive and align the sensor cell, which uses a conical collecting surface to channel the sweat directly and anaerobically from the sweat ducts to the continuous flow-through conductivity cell within its body. A crib-side analysis unit incorporates an iontophoretic power supply and displays a continuous readout of sweat electrical conductivity. The average conductivity during a specific time interval and the initial sweating rate are automatically displayed. The method, which simplifies sweat tests, is currently being assessed in three neonatal clinical trials to test its ability to reduce test failures in the newborn due to insufficient sweat.

scholarly journals Improving of operation stability of frequency converters with active rectifiers in electric steel-making complex electrical equipment switching

Vestnik IGEU ◽  
2019 ◽  
pp. 48-58
Author(s):  
A.A. Nikolaev ◽  
A.S. Denisevich ◽  
V.S. Ivekeev
Keyword(s):  
Control System ◽  
Power Supply ◽  
Electric Arc ◽  
Voltage Sags ◽  
Parallel Operation ◽  
Frequency Converters ◽  
Active Rectifier ◽  
Arc Furnaces ◽  
Operation Stability ◽  
Active Rectifiers

Frequency converters with active rectifiers (FC-AR) are now used in rolling mill electric drives. Modern control systems of ARs are not adapted to voltage sags in power supply systems, which leads to converter tripping. The known methods of ensuring AR operation stability, such as kinetic buffering, correction signals based on negative sequence voltage and others, do not eliminate these emergency trips. As an additional measure the paper proposes the method of voltage sag compensation by using static var compensators (SVC) of electric arc furnaces (EAF) for parallel operation of frequency converters with active rectifiers and electric arc furnaces. However, it remains unknown how disturbances (such as overvoltages of switching of SVC harmonic filters (HF) and voltage sags during furnace transformer switching) affect operation stability of frequency converters with active rectifiers. All this makes it necessary to study the effect of these processes on the operation conditions of FC-AR and to improve the active rectifier control system. The authors used experimental arrays of instantaneous values of voltages and currents of the real-life complex «EAF-SVC» («Electric Arc Furnace – Statistic VAR Compensator») in this study. They also applied mathematical models of FC-AR with different PWM algorithms realized in Matlab-Simulink software. The main assumption of the model consists in using equivalent current sources modelling the operation of autonomous voltage invertors. An improved control system of AR has been developed. The main feature that distinguishes it from the known systems is the fact that it ensures operation stability during SVC harmonic filter and EAF transformer switching by using a signal conditioning unit for setting the active rectifier reactive current component as a function of power supply and AR input voltage difference. Implementation of the improved AR control system improves FC-AR stability during parallel operation with EAFs through reactive power consumption of the supply system. As a result, it reduces the amplitude of inrush current and voltage deviations in the DC-link of the FC-AR to the values lower than the setpoints of the AR protection system.

scholarly journals Unidirectional DC/DC Converter with Voltage Inverter for Fast Charging of Electric Vehicle Batteries

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4791
Author(s):  
Jerzy Ryszard Szymanski ◽  
Marta Zurek-Mortka ◽  
Daniel Wojciechowski ◽  
Nikolai Poliakov
Keyword(s):  
Renewable Energy ◽  
Power System ◽  
Electric Vehicle ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
Dc Microgrid ◽  
Frequency Converters ◽  
Charging Station ◽  
Fast Charging ◽  
Variable Speed Motor

The paper proposes the adaptation of the industrial plant’s power network to supply electric vehicle (EV) fast-charging converters (above 300 kW) using renewable energy sources (RESs). A 600 V DC microgrid was used to supply energy from RESs for the needs of variable speed motor drives and charging of EV batteries. It has been shown that it is possible to support the supply of drive voltage frequency converters (VFCs) and charging of EV batteries converters with renewable energy from a 600 V DC microgrid, which improves the power quality indicators in the power system. The possibility of implementing the fast EV batteries charging station to the industrial plant’s power system in such a way that the system energy demand is not increased has also been shown. The EV battery charging station using the drive converter has been presented, as well as the results of simulation and laboratory tests of the proposed solution.

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