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With the increase in power rating of electric vehicle chargers, concerns regarding their integration to the grid have likewise grown. This paper investigates a novel technique for start-up of high-power fast electric vehicle (EV) charger using a solid-state inrush current limiter (SSICL). The circuit consists of three similar sets of bidirectional switch and limiting resistor that utilizes a control strategy based on a simple Kalman filter (KF) to suppress the converter start-up current and transient overvoltages. In fact, the built-up profile of the inrush current is dictated in accordance with the estimated current by the slow dynamic KF. Compared to alternatives, such as start-up resistors, the presented SSICL achieves faster start-up with comparable peak current, tends to provide lower distortion, and provides a good balance between speed and efficiency. Simulation and experimental results confirm that the proposed method can considerably suppress inrush currents, while improving the total harmonic distortion. Comparing the behaviour of the SSICL to other relevant techniques underlines the advantages of the proposed solution. Furthermore, although the focus of this paper is start-up of the fast EV chargers, the proposed circuit can act as an inrush-current limiter in most AC to DC converter structures. [ABSTRACT FROM AUTHOR]

This study presents a hierarchical control strategy for an auxiliary power unit (APU) for aircraft to coordinate multiple power sources and control developed power electronic interfaces. The study benefits from the presence of a hybrid energy system in paralleled structure to the main generator as the complementary system. The employed structure enhances power quality and improves the voltage profile of the high-voltage DC bus. Furthermore, the developed bi-directional topology provides the possibility of interaction with the grid. Considering the APU features in an aircraft, a hierarchical control strategy with different levels of control, timescale, dynamic response, and significance are developed. The developed controller consists of a power management algorithm in the higher level, and local voltage and current controllers in the lower one. The algorithm aims to maximise the PV sub-system utilisation, overcome voltage fluctuations, increase power density, reduce operation costs, and increase system availability while allowing further development to larger systems. Simulation and experimental results confirm the robustness of the algorithm. The result shows that the proposed power sharing strategy optimises the system utilisation while achieving a high-quality voltage profile under severe fluctuations. Moreover, the stress on the battery pack is reduced to improve the life cycle and reduce operation costs. [ABSTRACT FROM AUTHOR]

Electric arc furnace (EAF) is one of the largest non‐linear loads in power systems. It is highly time‐varying which leads to low‐frequency voltage fluctuations in the system, called flicker. Static VAr compensator (SVC) is always used in EAF plants to compensate the reactive power and reduce voltage fluctuations. The reactive power calculation unit is one of the most important units in SVC control system. Since SVC can only compensate the fundamental component, the calculated reactive power should not be sensitive to other harmonics. On the other hand, since the reactive power changes every half cycle, its calculation should be fast enough to track the changes. Hence, a calculation method with minimum delay and lowest harmonic sensitivity should be utilised to achieve an effective compensation. Among different already proposed methods for calculation of reactive power, differential method has the lowest delay. However, it is very sensitive to harmonics. In this study, Kalman filter is used to extract the fundamental components of voltage and current with a little delay and then they are used as inputs for the differential method. The proposed method is evaluated using some simulation signals and practical records from several EAFs in Mobarekeh steel company in Esfahan – Iran. [ABSTRACT FROM AUTHOR]

This study deals with a developed thyristor based bridge‐type fault current limiter (TBFCL), in which the main fault current limiting function is relegated to a limiting circuit controlled by a silicon controlled rectifier (SCR). Since SCR is a reliable power electronic switch and can be found in high ratings, the proposed TBFCL can be utilised in higher ratings in comparison with other proposed BFCLs. The TBFCL limits fault current in two steps; (i) by a fully controlled DC reactor during transient fault interval (ii) by a SCR based current limiting circuit during steady state fault interval. The TBFCL has a bridge‐type DC reactor controlled by an isolated gate bipolar transistor and a current limiting circuit in parallel with the bridge controlled by a thyristor. Upon fault occurrence, the DC reactor limits increasing rate of the fault current, while the generated over voltage activates auto‐triggering control circuit of the SCRs. Therefore, the fault current is limited through the SCR current limiting path and the DC reactor path is interrupted. Analysis of the proposed TBFCL is presented in detail. Simulation and experimental results verify the performance of the TBFCL. [ABSTRACT FROM AUTHOR]