This article proposes a new bidirectional isolated LLC resonant converter, which is suitable for ultra-wide voltage gain range applications, such as electric vehicle charging systems. The inverter and rectifier of proposed topology both have two modes by reconfiguring different modulation schemes during operation. results in three voltage-gain ranges, allowing ultrawide output operation over narrow frequency. conversion ratio tank can be designed only quarter the required range. Finally,...

The three-phase series-connected modular multilevel converter (SC-MMC) is presented as one option for high-voltage direct current (HVDC) tap to reduce the cost of an HVDC station. Compared with conventional parallel-connected MMC, number semiconductor switches in SC-MMC reduced by one-third withstand same dc voltage. First, paper studies operating principle SC-MMC, and then presents interspacing phase-shifted pulsewidth-modulated method which could improve waveform output ac voltage a given...

Similar to the conventional three-phase parallel-connected MMC (PC-MMC), series-connected (SC-MMC) is a strong potential solution for high-voltage direct current (HVDC) applications. The study of SC-MMC focuses on control strategy, neglecting its small-signal dynamics, not mention stability when interacting with AC grid. Work modeling limited configurations. differs from PC-MMC in structure and harmonic content; hence, it necessary establish an accurate model according own characteristics....

In this paper, a numerical study of two-phase flow instability in parallel rectangular channels is presented. Using the homogeneous model, marginal stability boundaries (MSBs) are derived parameter space defined by phase change number (Npch) and subcooling (Nsub) under various operating conditions. Comparison with experimental data shows that model predicts trends deviation ±12.5%. The reveals that, constant mass flux conditions, decreases as equivalent diameter (De) increases. Additionally,...

Distributed generation supply efficiency can be fully realized with the use of a microgrid as power interface and an efficient operation control technique. The key component AC/DC hybrid is interlinking converter, which enables flexible interactions between AC DC subgrids. This paper proposes adaptive droop strategy for multiple ICs in microgrid. not only reduce unnecessary flow subgrids, but it also compensate bus voltages. With proposed strategy, problem inaccurate distribution existing...

Active switched inductor (ASL) dc–dc converters have very high step-up voltage gain but practically they suffer from stress across switches because of the resonance caused by mismatch among values and switch parameters. This article presents a new hybrid dc-dc converter topology derived ASL passive capacitors (PSC). The proposed has over wide range duty cycle. due to parameters is eliminated. low stress, current on circuit elements, common ground between input output ports. configuration,...

Resonant frequency and impedance matching have great significance for the vibration performance online monitoring of rotary ultrasonic machining. Network compensation is a typical solution to match resonant between holder (RUH) transducer. However, traditional bilateral method could adversely affect dynamic balance RUH. Currently, existing unilateral methods can only realize matching. A novel that satisfies both proposed. First, model RUH vibrating system established according its equivalent...

An adaptive normalized droop control strategy for the interlinking converter of hybrid microgrid has been proposed in this paper. The standard can realize bidirectional power coordination between subgrids. However, transmission accuracy is low, and subgrid bus voltage varies from rated value. avoids unnecessary flow so as to achieve accurate effective deviation compensation. In study, low AC/DC examined. It be deduced mathematics that increase coefficient improve accuracy. variation added...

With the development of HVDC transmission system, research direct current circuit breaker (DCCB) has drawn attention many scholars. This paper summarizes new DC breakers in recent years, including auxiliary and control method DCCB. In addition, this introduces DCCB with cascade module, device combination test for breaker. The topology principle, advantages main problems high voltage (HVDC) application are discussed. possible future direction related put forward.

Active commutated or naturally clamped techniques have emerged as a new solution to achieve wide range soft-switching and eliminate the necessity of active clamping circuit current-fed bidirectional dc/dc converter. Multiple typical modulation schemes been proposed, which include single phase-shift (SPS) modulation, dual (DPS) discontinuous current SPS (DCSPS) modulation. DCSPS provides lowest circulating compared with prior two modulations, but it suffers from problem resonance high peak at...

Abstract Rotary ultrasonic machining (RUM) is an effective solution to cut, grind, or drill the advanced brittle hard materials. Contactless rotary transformer, with advantages of high-power transmission efficiency and reliability, a potential structure transmit electric power in RUM. In this study, impedance model holder (RUH) established find that there exist deviations for resonant frequency between RUH transducer, indicating without compensation transducer cannot precisely its own by...

A battery energy storage system based on MMC (MMC-BESS) is discussed, the has active and reactive comprehensive compensation capability. The MMC-BESS applied in wind farm integration, which can smooth power fluctuations improve voltage of bus effectively. Bidirectional DC/DC link used to parallel batteries with DC side submodule, state charge (SOC) balance control strategy are proposed. capacity expanded application a coordinated transient proposed when unusual. feasibility topology...

The oscillating wave test system (OWTS) which is similar to power frequency can be used the partial discharge of cable insulation defects. It proved that using OWTS bring many benefits such as it make result normative, and not harmful totally suitable for field test. In order study PD characteristic XLPE under voltage, four typical defects at different severity are designed withstand voltage. are: A) air-gap defect located joint, B) cusp semi-conducting layer, C) overly long or short overlap...

This paper introduces a three-phase series-connected asymmetric hybrid modular multilevel converter (SCAH-MMC) tap which not only retains the technical advantages of MMC, but also has capability to cope with dc faults. Basic operation principle SCAH-MMC is presented. It shows that troubled by inherent third harmonic single-phase ac power. By adding feed-forward modulation signal, third-harmonic currents can be significantly reduced. The mathematical formulas and claims are validated...

Solid oxide fuel cells are one of the most attractive cell technologies, promising to establish off-grid distributed power systems in remote areas. On-site hydrogen production through diesel reforming can be a viable solution problem storage and transportation. In this paper, catalyst based on non-noble metal Ni, with addition La K, is prepared studied. The performance tested under various reaction conditions experiments. optimal determined. Coke formation found spent catalyst. produced...

Abstract In a hybrid AC/DC microgrid (MG), the interlinking converter (IC) plays an important role in power flow regulation between subgrids. However, line impedance will cause deviations transmitted by IC if communication device is not used. To realize accurate delivery subgrids without communication, control method based on compensation proposed. A harmonic signal injected into this using converters of distributed generation, which are connected to AC bus. The specified frequency...

The performance of a 4-station Multi-Terminal MMC HVDC system (MTDC-MMC-HVDC) is predicted by numerical integration 57 first order Ordinary Differential Equations (ODEs). Wind power oscillation also considered in this model. Because larger step-size can be used the ODEs, to simulate same size MTDC-MMC-HVDC system, computations speed our model increases over SIMULINK MATLAB (fully detailed switching model) factor 240. Fast simulation methods are necessary design systems.

Abstract In this paper, a flexible power dispatch strategy based on the elliptical trajectory is proposed to maximize operating region for dynamic voltage restorer (DVR) during sags. This control scheme introduces two individual parameters accomplish continuous delivery within security boundaries required by loads. These key are presented in exact mathematical equations of instantaneous dispatch, which allows active and reactive DVR. Under provisions given strategy, load regulation combined...

In order to solve the problem of virtual power loss introduced by L/C-based switch model in real-time simulation electronic converters, a modified algorithm is proposed which can be adopted model. This paper analyzes causes from numerical perspective and concludes that primary cause initial error during switching. Therefore, an additional eliminate it. To minimize impact on computation speed resource consumption field-programmable gate array (FPGA) simulation, FPGA implementation...

Building a new type of power system is the key to realizing China's "dual carbon" goal and promoting green low-carbon energy transformation. To explore path transformation, this paper constructs high-resolution model, combining long-term capacity planning with hourly operation simulation. The results indicate that will achieve carbon peak around 2030, focus investment at different stages should be adjusted. In future, generation dominate, wind becoming main source, followed by photovoltaic...

The fault diagnosis function of the battery management system (BMS) is crucial for pack safety and reliable operation. This paper proposes a new series-parallel connected voltage measurement design scheme, which can save sensors number from n to 0.75n cells in series. multi-fault strategy proposed by analyzing law current signals. Three kinds fault, including connection sensor micro external short circuits (mESC) were simulated verify effectiveness strategy. provides an important reference...