With increasing penetration of the renewable energy, grid-tied PWM inverters need to take corresponding responsibilities for security and stability future grid, behaving like conventional rotational synchronous generator (RSG). Therefore, recognizing inherent relationship intrinsic differences between RSGs is essential such target. By modeling typical electromechanical transient inverters, this paper first proves that are similar in physical mechanism equivalent mathematical model, concept...

Unlike the typical microgrid with a common ac bus, networked always suffers more serious reactive power sharing issues due to its complex inner structure. In such case, system error cannot be easily evaluated and eliminated. So, this paper proposes wireless control strategy that employs optimized virtual impedance controllers local load measurements for in microgrid. First, from modeling of network, an estimation method network is derived. Through method-based feature analyses, corresponding...

A fast and effective service restoration method is proposed for medium-voltage distribution system with distributed generators by combining intentional islanding of network reconfiguration to maximize out-of-service loads. The whole process divided into four stages: 1) matching schemes; 2) connectivity generators; 3) reconfiguration; 4) optimization load shedding. Whether the last three stages are executed or not depends on violations operational constraints. In accordance topological...

This paper proposes a novel three-phase phase-locked loop (PLL) algorithm, which focuses on the reforming of primary signals before grid synchronization rather than improving phase estimation methodologies. The unbalanced are reformed to balanced ones without damage angle, through negative sequence voltages is removed. eliminates errors conventional synchronous reference frame PLL and enhances its response speed with higher bandwidth. process supposed be carried out at every zero-crossing...

To solve the reactive power sharing issue in droop control application, many solutions have been developed based on basic wireless manner. However, existing methods cannot eliminate errors effectively, especially load change situations. In this paper, a method that employs feeder current sensing and adaptive virtual impedance is proposed for islanded microgrid. improve accuracy of method, an equivalent concept introduced, which can reflect mismatch connecting circuits equivalently. Through...

The capacitor-inductor-inductor-capacitor (CLLC) resonant converters are drawing more and attention for their superiority in soft switching, wide output range, symmetrically bidirectional operation. However, CLLC converter still suffers the problems of unsatisfactory voltage regulation low efficiency under light-load conditions. Therefore, this article proposes an optimization extended phase-shift (EPS) control full-bridge to improve efficiency. In order study relations between phase-shifts...

Dual-active-bridge (DAB) based dc–dc converter is usually chosen for energy conversion. In this article, there exist many coupled relationships such as the controversy between local minimum current stress and transmission power, which influence efficiency promotion greatly. To analyze complicated relationship obtain global values, after unifying backflow power into one integral function, a novel extended-phase shift (EPS) control on complete differential algorithm proposed, can not only...

Dual active bridge (DAB) is a popular interface between energy sources and electric vehicle storage systems because of its galvanic separation, bidirectional power transmission, extensive voltage adjustability. To overcome the drawbacks conventional modulations, an optimal primary-side duty modulation (OPDM) proposed in this article, which combines phase-shift asymmetrical on primary side to achieve compromise high efficiency performance lower control complexity. begin with, under...

Abstract Triboelectric nanogenerator (TENG) has received significant attention as an energy harvesting technology capable of converting mechanical from the environment into electrical power. However, due to its inherent high impedance and low charge transfer output characteristics, TENG is often relatively small. Current research typically focuses on switching off under intrinsic voltage for performance management. To further improve performance, management strategy proposed that aimed at...

Due to the increased concern about energy and environmental issues, significant attention has been paid development of large-scale storage devices facilitate utilization clean sources. The redox flow battery (RFB) is one most promising systems. Recently, high cost transition-metal complex-based RFB promoted aqueous RFBs with redox-active organic molecules. To expand working voltage, computational chemistry applied search for molecules lower or higher potentials. However, potential...

With inhomogeneous irradiance on photovoltaic (PV) units significantly deteriorating the effectiveness of solar energy harvest, distributed maximum power point tracking (DMPPT) concept is considered as an effective solution against resultant mismatch. A comparative analysis full processing and differential structures, two main branches DMPPT solution, provided first. Advantages disadvantages widely used structures are analyzed compared from different aspects. To harvest more realize better...

Weather-dependent photovoltaic (PV) system power variation may become frequent and rapid, which could be regarded as perturbation for the microgrid (MG). This would lead to voltage frequency fluctuations dramatically degrade MG performances. Conventional secondary control strategy restore after a certain time delay, but it cannot satisfy speed demands when rapid perturbations appear. To overcome limitation, this paper proposes novel real-time compensation suppress fluctuations. The proposed...

Inertia emulation in inverter control strategies benefits improving dynamic frequency performance a microgrid. Therefore, some introduce virtual inertia, and the corresponding is investigated. These mainly focus on dynamics from perspective of an inverter, whereas their influence ac bus interaction among different inverters are still unclear. This paper aims to investigate multiple generation units both grid-connected islanded modes considering inertia interaction. A transfer function model...

The active power control of increasing renewable energy resources is a growing concern. For example, solar exploitation highly dependent on the central controller and other resources. Previous research has introduced some solutions for this problem, but performance usually unsatisfactory in allocation, communication dependence, mode switch, algorithm complexity. This article proposes straightforward effective strategy two-stage photovoltaic (PV) inverter, which uses voltage-control method to...

To ensure efficient energy charging process inside storage system, dual-active-bridge (DAB) becomes significant interface circuit because of its bidirectional power transmission ability and simple modulation scheme. In order to achieve DAB efficiency promotion, lower root-mean-square (RMS) current stress wider soft-switching region are required. Therefore, a multiple duty (MDM) is proposed aforementioned goals. this article, detailed derivations mathematical models for typical MDM modes...

The surface charge distribution under impulse voltage is measured using a static capacitance probe. A probe with very small leakage designed. condition of accumulation analyzed, and it concluded that micro discharges in the gas near insulator such as corona caused by free fixed metal particles usually prerequisite condition. dynamic equation describing relationship between density applied established, process analyzed. Theoretical analysis experimental results show decrease wave front time...

In automated manufacturing systems (AMSs), deadlock problems must be well solved. Many control policies, which are based on siphons or Resource-Transition Circuits (RTCs) of Petri net models AMSs, have been proposed. To obtain a live controller small size, this paper proposes for the first time concept transition covers in models. A cover is set Maximal Perfect RTCs (MPCs), and its MPCs can transitions all MPCs. By adding place with proper variable to each MPC an effective make sure that it...

Dissolved gas analysis (DGA) is a popular method for diagnosing faults inside power transformers. However, some of the recorded data are with ambiguous characteristic, leading to misdiagnosis conventional methods. In this work, hybrid method, which combines relevance vector machine (RVM) and adaptive neural fuzzy inference system (ANFIS) has been proposed address issue. Given fuzziness between DGA records fault type, minimise number rules that ANFIS needs extract, RVM algorithm performs...

For distributed energy storage system, dual-active-bridge (DAB) is often employed as interface among photovoltaic port, system and load. Efficient DAB operation will be beneficial to conversion efficiency. Nevertheless, for conventional modulation, many problems exist including that wider soft-switching range always accompanied with high peak current. In order overcome these problems, a double-side asymmetrical phase-shift modulation (DAPM) proposed, which combines on the primary side...