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This paper proposes a mixed-integer quadratic programming (MIQP) model for optimal day-ahead distribution networks dispatch considering Wind Generators (WGs) and topology reconfiguration. Firstly, linearized current injection model is introduced for generators by a series of approximations. Then the day-ahead Switching Operations (SOs) of reconfiguration could be calculated in a linear form based...
A control strategy to manage the circulating current content in a Modular Multilevel Converter in direct AC-AC topology is proposed in this article. The converter is connected in three-phase YDY configuration which forms a closed delta path for free current circulation while keeping outsider waveforms with low THD content. Circulating current correction becomes necessary face to any kind of unbalance...
The hybrid high voltage direct current (Hybrid HVDC) system based on line commutated converter (LCC) and modular multilevel converter (MMC) is a feasible solution for long distance bulk power transmission. In order to handle the dc-side short-circuit fault, two kinds of methods can be adopted. The first one is to replace half-bridge sub-modules (HBSMs) with full-bridge SMs or clamp-double SMs which...
This paper considers a framework of electrical cyber-physical systems (ECPSs) in which each bus and branch in a power grid is equipped with a controller and a sensor. By means of measuring the damages of cyber attacks in terms of cutting off transmission lines, three solution approaches are proposed to assess and deal with the damages caused by faults or cyber attacks. Splitting incident is treated...
This paper introduces a novel battery cell balancing technique for portable applications, where multiple series connected lithium-ion battery cells are utilized. The equal discharge of the battery cells are achieved through a simple modification of a hybrid step-down dc-dc converter, where only an additional resonant inductor is required. Hybrid converters, combining switched-capacitor and inductor...
In the situation that the modular multilevel converter (MMC) needs to maintain a good current control performance within a wide scope of operations such as the intermittent new energy grid connection and electric locomotive, etc, this paper starts from the output current slope generated after the output voltage and system voltage of MMC converter are jointly acted on the equivalent coupling reactance...
A transformer-less Modular Multilevel DC-DC converter for High Voltage Direct Current (HVDC) applications is proposed in this paper. This topology is suitable for interfacing two HVDC links at different voltage levels using only conventional half bridge submodules. The uniqueness of the proposed converter is in its symmetry in performance in the event of reversal of polarity of one of the DC links...
A novel topology is proposed that interfaces between one or multiple DC sources and a three-phase machine. The DC-side converter consists of two half-bridges that form a specialized converter. The half-bridges operate at a reduced voltage which reduces inductor effort and switching losses. The resulting four DC-link levels power two three-phase bridges that can drive open-winding machines. The circuit...
DC fault protection is one of the biggest challenge to multi-terminal direct current (MTDC) systems, because DC current has no natural zero crossing point. To overcome this problem, hybrid DC circuit breaker (DCCB), which serves as a promising solution to the isolation of DC faults, has been developed. However, hybrid DCCB contains a huge number of power semiconductors, which is costly and inefficient...
Traditional half bridge dual buck inverter (DBI) has a low power density due to the employing of two large input capacitances and two discrete output inductors. Magnetic integration is an effective method to enhance power density. However, unexpected circulating current may be induced by adopting conventional magnetic integration scheme. This paper proposes a novel magnetic integrated DBI inverter,...
High frequency is an effective method to improve transmission efficiency of inductively coupled power transfer (ICPT) system. However, it is hard for the high capacity semiconductor device to meet the high frequency need. In this paper, a novel multiple-frequency inductively power transfer system is proposed. By adopting a novel multiple-frequency topology of inverter, the transfer frequency of the...
A quasi single-stage power factor correction converter, which is composed of a three-level (TL) Boost converter and a DC-DC transformer (DCX), is presented and analyzed in this paper. The DC output load is connected to one of the dividing capacitors of the TL Boost converter, so that the load voltage can be lower than the peak amplitude of the AC line voltage and part of the AC input power can be...
Vienna rectifiers are widely utilized in various industry applications due to low cost, high reliability and better EMI performance. However, the DC bus voltage balancing is always an issue to be considered due to the 3-level structure. Several DC bus balancing control methods are proposed during last decade. But these methods either require a large amount of calculations or cause inaccuracy at voltage...
There is a conflict between the energy transfer efficiency and maximum transferred power in conventional inductive power transfer (IPT) systems, and the energy transfer efficiency is only 50% when maximum power is transferred. To solve this problem, a new topology which is operated at switched-mode is proposed in this paper. The high frequency current of the topology is generated by the free oscillation...
The interleaved bidirectional DC-DC converter is a core component of the battery energy storage system. However, if an open-switch fault occurs at the interleaved bidirectional DC-DC converters, the currents of two branches will become unbalanced, which will increase the battery current ripple and shorten the life of batteries and energy storage systems. In this paper, a fault tolerant topology is...
Performance analysis and output voltage regulation of a cascaded step-up switched-capacitor converter (SCC) under zero voltage switching (ZVS) condition is analyzed in this paper. The ZVS condition (converter operation above its resonant frequency) provides 1) zero-voltage switching, which leads to a relatively higher efficiency compared to zero current switching (ZCS) under the resonant frequency...
Blockchain technology is a kind of distributed database network, which provides the P2P (Peer-to-Peer) digital currency transaction mode through the encryption algorithm and the decentralized mechanism. This paper is to study the application of blockchain technology related to industry 4.0, and put forward blockchain technology in the cooperative development of power electronic devices. The above...
DC capacitor voltage imbalance is an inherent problem limited the further development of multi-level Neutral Point Clamped (NPC). In this paper, a new hybrid control method based on Space Vector Pulse Width Modulation (SVPWM) for five-level NPC at high modulation index and high power factor is presented. By choosing appropriate switching pattern in lower modulation index sectors and collocating different...
In this paper, a topology of three-phase buck rectifier which is suitable for the low output voltage application and its control principle are proposed to reduce the cost and simplify the control. The proposed topology uses the phase voltage instead of the line voltage to supply power. Thus, it can decrease the rating voltage of switching devices, and save the cost. Moreover, the proposed control...
Energy storage technology is an important measure for power output of new energy generation system. T-type three-level structure is adopt as the topology of energy storage inverter. Mathematical model of grid-connected operation in ABC coordinate system and dq coordinate system is built. A double closed loop control strategy of which inner loop current and outer loop power control is proposed. The...
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