Inrush Current Limiter Research Articles

An Active Inrush Current Limiter Based on SCR Phase Shift Control for EV Charging Systems

An Active Inrush Current Limiter Based on SCR Phase Shift Control for EV Charging Systems

Battery management system with active inrush current control for Li-ion battery in light electric vehicles

This paper presents a design concept of integrating an inrush current control function into a battery management system (BMS) for Li-ion battery used in light electric vehicles. The proposed concept exploits the existing discharge MOSFET, which has the primary function as an electronic circuit breaker, for the secondary function as an inrush current limiter. The proposed inrush current control function is implemented as an adaptation based on an existing BMS platform. The gate control circuit is redesigned together with an adaptation of the BMS software. Both hardware and software adaptations do not lead to any significant increase in material costs. The major technical challenge of the proposed concept is finding an appropriate trade-off design between the performances of two functions, cutting off circuit and limiting inrush current. The design procedures are presented along with technical discussions for making design compromises. At the end, the functionality of the proposed technique is validated by experimental results.

Bidirectional impedance-type transformer inrush current limiter

Transformer inrush current is harmful to the transformer's windings and may bring about inadvertent tripping of the protective relays. In order to reduce the magnitude of inrush current, a bidirectional impedance-type inrush current limiter (BIT-ICL) is proposed in this paper. When a power transformer is energized, the BIT-ICL immediately and automatically inserts into the circuit to suppress the inrush current without any control or detection circuit. After completing transformer inrush suppression, the BIT-ICL is bypassed automatically, and the transformer appears to connect directly to the voltage source. Thus, when the transformer is loaded, there is almost no distortion in the steady-state load voltage and current waveforms due to the voltage-compensation effect in the limiter. The feasibility and performance of the proposed BIT-ICL are verified by a low-voltage single-phase power transformer under different residual flux and load conditions. Moreover, as long as the power loss that results from the related components in the BIT-ICL can be greatly reduced, this limiter can be applied to high-voltage and large-capacity distribution transformers.

Improved bridge type inrush current limiter for primary grounded transformers

This paper presents a new method for suppression of the transformer inrush current of primary grounded transformers. A newly designed diode-bridge in a neutral winding transformer controls the inrush current using simple power circuit topology without any control or gate drive circuits or measurement tools. Since the number of diodes in this design has been minimized, the ripple and electrical losses decrease while operational reliability increases. The proposed method has been evaluated in laboratory tests and computer simulations. The good agreement of experimental and simulation results verifies the effectiveness of this method.

Application on of SFCL in Automatic Power Changeover Switch System of Electric Railways

This paper proposes automatic power changeover switch system applied superconducting fault current limiter (SFCL) of the Korea electric railway using 25 kV-AC Scott transformer. The electric railway needs neutral section to separate two different electrical power phase to m phase and t phase. While the train passes through the neutral section, the electrical power supply phase is changed over to other phase. And that time, the train must turn off the circuit breaker to avoid transient as `inrush-current' and `arc'. These cause negative problems as speed decline of the train, a shorter life of the train circuit breaker. To improve the problems, the inrush current limitation method is proposed. In addition, we analysed the effect of proposed method using time-domain transient simulation software (PSCAD/ EMTDC).

Inrush current limiter based on three-phase diode bridge for Y-yg transformers

In this study, a simple, but effective method is presented for the limitation of the Y-yg transformers inrush current. One of the main privileges of this method is its simple topology. It does not need any control circuit or measurement unit. The method is based on a three-phase diode bridge with a low resistance DC reactor. Since the number of diodes is minimised, the voltage ripple, electrical losses and the malfunction probability owing to device failure are decreased considerably. The proposed method is simulated and validated by experimental test results. It is shown that the proposed configuration is effective for the inrush current limitation of Y-yg transformers.

Efficient resonant-type transformer inrush current limiter

This study presents a new structure of a solid-state inrush current limiter (SSICL) to mitigate the inrush current of transformers. The proposed SSICL has a series–parallel resonant structure that is formed by two resonant circuits tuned at the supply frequency. During the energisation of transformers, the SSICL offers very high impedance by the parallel resonant circuit; therefore inrush current is dramatically reduced. Under normal conditions, an SSICL exhibits very low impedance through the series resonant circuit. By energising the transformer, an auto-triggered silicon-controlled rectifier (SCR) circuit inserts the parallel resonance circuit in the transformer input terminals. In addition to the self-controlling capability, the proposed SSICL can be triggered by an external command. This effective remedy assures the proper operation of the transformer protection system. Therefore with a very simple structure, it has a fast and reliable performance as well as full control capability. A prototype single-phase SSICL is simulated by electro-magnetic transient program (EMTP) and tested. The simulation and experimental results show that the proposed SSICL considerably reduces the inrush current during the energisation process of the transformer.

Voltage compensation-type inrush current limiter for reducing power transformer inrush current

When a transformer is initially energised, its iron core is driven into saturation, which will result in high-amplitude magnetising inrush current. For lessening this transient phenomenon, a voltage compensation-type inrush current limiter (VCT-ICL) is presented in this study. The VCT-ICL can automatically insert high impedance to restrain the sudden change in line current. After completing the restriction of inrush current, the VCT-ICL freewheels, and acts as a short circuit. Thus, other than performing the restriction, the VCT-ICL has a negligible effect in the circuit and the transformer seems to connect directly with the voltage source. When a load is connected at the secondary side of the transformer, to adjust the magnitude of DC reactor current so that it is equal to or higher than the peak of line current, there is almost no distortion to the load voltage and current waveforms during the steady state. A 5 kVA single-phase power transformer is used as an example to demonstrate the performance of the proposed limiter. According to the simulated and experimental results, the feasibility of the VCT-ICL has been verified. Moreover, increasing the insulation levels of the related components in the proposed limiter allows it to be applied in high-voltage distribution transformers.

A low power, on demand electrothermal valve for wireless drug delivery applications

We present a low power, on demand Parylene MEMS electrothermal valve. A novel Omega-shaped thermal resistive element requires low power (approximately mW) and enables rapid valve opening (approximately ms). Using both finite element analysis and valve opening experiments, a robust resistive element design for improved valve opening performance in water was obtained. In addition, a thermistor, as an inrush current limiter, was added into the valve circuit to provide variable current ramping. Wireless activation of the valve using RF inductive power transfer was demonstrated.

DC reactor type transformer inrush current limiter

A new inrush current limiter (ICL) is presented to limit the inrush current of transformers. The proposed ICL consists of three similar sets. Each set includes a diode-bridge and a single DC reactor and is connected in series with the individual phases of transformer. The ICL has almost no effect on normal operation of transformer. It needs no control, measurement and gate driving system and has a simple power circuit topology. The equivalent instantaneous inductance of transformer is used for analysis of circuit operation. The theoretical analysis, design features, power losses and voltage distortion because of using ICL are presented. The proposed method has been tested by simulation and laboratory experiments. Both results show that the proposed ICL successfully limits the inrush current.

5436824 Inrush current limiter in a magnetic flowmeter : Royner Bruce; Coursolle Thomas Eden Prairie, MN, United States assigned to Rosemount Inc

5436824 Inrush current limiter in a magnetic flowmeter : Royner Bruce; Coursolle Thomas Eden Prairie, MN, United States assigned to Rosemount Inc