In a dc microgrid (DC-MG), the bus voltage is vulnerable to power fluctuation derived from intermittent distributed energy or local loads variation. this paper, virtual inertia control strategy for DC-MG through bidirectional grid-connected converters (BGCs) analogized with synchronous machine (VSM) proposed enhance of DC-MG, and restrain fluctuation. The small-signal model BGC system established, transfer function between output current deduced. dynamic characteristic in analyzed detail. As...

Traditional grid-connected inverters (TGCI) could suffer from small-signal instability owing to the dynamic interactions among and a weak grid. In this letter, sequence impedance model of virtual synchronous generator (VSG) is built, characteristics VSG TGCI are compared analyzed. The mainly capacitive in middle-frequency area, amplitude quite high. By contrast, VSG, being consistent with grid characteristics, generally inductive, low. Based on Nyquist stability criterion, influence...

The premise that the virtual synchronous generator (VSG) can actively support weak grid is VSG operate stably. In this paper, small-signal sequence impedance models of voltage-controlled and current-controlled are built characteristics these two types VSGs compared analyzed. VSG, being consistent with characteristics, generally inductive. By contrast, mainly negative in middle- high-frequency area amplitude quite low. Based on stability criterion, influence weakness grid-connected system...

Abstract Rechargeable lithium–metal batteries with a cell‐level specific energy of >400 Wh kg −1 are highly desired for next‐generation storage applications, yet the research has been retarded by poor electrolyte–electrode compatibility and rigorous safety concerns. We demonstrate that simply formulating composition conventional electrolytes, hybrid electrolyte was constructed to ensure high (electro)chemical thermal stability both Li‐metal anode nickel‐rich layered oxide cathodes. By...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, a combined system of static var compensator (SVC) and active power filter (APF) was proposed. The has the function factor correction, voltage stability, harmonic suppression. SVC, which consists delta-connected thyristor-controlled reactor (TCR) Y-connected passive (PPF), is mainly for stability correction. small rating APF used to harmonics generated by nonlinear load TCR in SVC...

We introduce a user-friendly steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) system. Single-channel EEG is recorded using low-noise dry electrode. Compared to traditional gel-based multi-sensor systems, sensor proves be more convenient, comfortable and cost effective. A hardware system was built that displays four LED light panels flashing at different frequencies synchronizes with acquisition. The stimuli have been carefully designed such risk...

In this paper, the control strategy for static synchronous compensator (STATCOM) used in utility distribution systems is investigated, and a novel fuzzy-PI-based direct-output-voltage (DOV) presented. Based on power balancing principle feedforward decoupling control, DOV cannot only reduce active reactive current loops of conventional double-loop but also achieve to regulate dc-link voltage maintain voltages at point common coupling (PCC). order effectively improve immunity capability...

In this paper, an improved control method for multiple bidirectional power converters is proposed to reduce the circulating current and power-sharing deviation among when hybrid ac/dc microgrid operated in island mode, which can enhance security of parallel converters. First, a unified detection described. Then, mode presented deviation, includes droop controller used achieve automatic sharing virtual impedance further deviation. At last, simulation experiment results verified that...

In order to eliminate the negative-sequence and harmonic currents in high-speed train traction systems with three-phase V/V transformers, a compensation strategy based on railway static power conditioners (RPC) is proposed this paper. An RPC contains two converters that are connected back by sharing same dc link. paper, structure principle compensate for transformer explained, provide references proposed. Also, method separate active current, reactive current from total given. Moreover,...

With the development of high-speed and high-power electrified railway, power quality traction grid becomes more serious. In order to achieve three-phase balance grid, a modular multilevel converter (MMC)-based railway conditioner (RTPC) is studied, which characterized by cascaded structure. The RTPC consists four H-Bridge links output filter inductors, can be connected 27.5-kV feeders in co-phase supply system directly. This used for different kinds system, especially suited Scott system....

Active power oscillation is observed when two or more parallel synchronverters undergo load fluctuations, potentially impacting the safe operation of synchronverters. This article provides a fundamental analysis for mechanisms and proposes new control strategy suppressing especially excitation proposed. It found that inherently caused by weak damping large inertia under condition undesirable instantaneous active sharing. Then, reducing synchronverters, which sharing, deduced. The effectively...

With the wide application of non-linear loads and large-scale access distributed energy generations based on power electronics equipments, quality problems in distribution network are increasingly serious with new characteristics. Further in-depth research is great significance theory practice. This paper provides an overview analysis, compensators, control technologies under situation smart grid. It focuses topologies methods for conditioners, especially characteristics applicable...

With the rapid development of high-speed and high-power railway system in China, power quality such as negative sequence current harmonic caused by electric locomotives becomes more critical. This paper proposes a half-bridge-converter-based static conditioner (RPC) (HBRPC) which consists two half-bridge converters connected capacitors series. Compared with traditional RPC, HBRPC requires only pair switch legs capacitors. Under premise accomplishing same function proposed can reduce half...

With the rapid development of modern electrified railway, negative-sequence current minimization is one most important considerations in high-speed railway traction system. In past, many multiple or multilevel topologies with high compensation capacity have been introduced for power conditioner (RPC). This paper presents a simplified quantitative comparison five previous modular RPC negative sequence V/V and SCOTT systems, aiming an optimal selection compensators. Performance criteria such...

Under weak grid, wind farm can easily cause subsynchronous resonance (SSR) owing to the impedance interaction between and grid. In this article, a synchronous compensator with battery energy storage system (STATCOM/BESS) is connected in parallel grid suppress SSR. Meanwhile, analogizing virtual generator (VSG), an enhancing stiffness control strategy proposed for STATCOM/BESS low rated active power high reactive power. According designed strategy, demand quantity of be reduced by more than...

For the LCL-type grid-connected distributed generation system, grid-current-feedback active damping (GCFAD) methods have a conflict between resonance-suppression ability and harmonic-currents amplification. this, an inverter-current-feedback reso-nance-suppression (ICFRS) method without additional sensors is proposed to reduce resonance-frequency offset grid-inductance effect due its unattenuated characteristic under high-frequency bandwidth. By analyzing two types of equivalent impedance...

It is meaningful to analyze urban spatial structure by identifying subcenters, and many methods of doing so have been proposed in the published literature. Although these are widely applied, they exhibit obvious shortcomings that limit their further application. Therefore, it great value propose a new subcenter identification method can overcome shortcomings. In this paper, we density contour tree (DCT) for detecting polycentric structures distributions. Conceptually, based on an analogy...

Analogizing the subsynchronous resonance (SSR) phenomenon of series-compensated grid-connected system based on synchronous generator, virtual generator (VSG) also has low-frequency oscillation problem owing to impedance interaction between VSG and network. Stability controlled by is analyzed impedance-based Nyquist stability criterion. Due inductive VSG, easy couple with network in areas, which can lead SSR. With increase series compensation level, becomes worse induced frequency higher....

This review summarizes linear spatiotemporal signal analysis methods that derive their power from careful consideration of spatial and temporal features skull surface potentials. BCIs offer tremendous potential for improving the quality life those with severe neurological disabilities. At same time, it is now possible to use noninvasive systems improve performance time-demanding tasks. Signal processing machine learning are playing a fundamental role in enabling applications BCI many...

This paper deals with a hybrid active power filter injection circuit (IHAPF). It shows great promise in reducing harmonics and improving the factor relatively low capacity filter. concluded that stability of IHAPF based on detection supply current is superior to others. To minimize IHAPF, an adaptive fuzzy dividing frequency-control method proposed by analyzing bode diagram, which consists two control units: generalized integrator unit adjustor unit. The used for frequency integral control,...

The proposed power electronic hybrid system which consists of a thyristor-controlled reactor (TCR) and resonant-impedance-type active filter (RITHAPF) is used for compensating reactive harmonic current. From the point nature load balancing compensation, calculation controlled susceptance based on voltage vector transformation TCR to exactly compensate negative-sequence current caused by asymmetrical loads in industrial field. Because impedance inductor, matching transformer, passive filters...

This paper presents a negative sequence compensation system based on novel two-phase three-wire converter to eliminate current for the high-speed railway traction power with three-phase V/V transformer. In this system, proposed is fed by two single-phase sources formed step-down transformers connecting feeder sections. The contains three switch legs, one of which connected common ground wire voltages. Hence, leg saved compared conventional converters, and ratings switches are not increased....

In the single-phase photovoltaic (PV) grid-connected distributed generation (DG) system located at end of feeder, it is necessary to provide quickly active and reactive power local loads. this paper, an improved current detection control method are proposed realize compensation. To detect loads current, a fast using derivative i <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> -i xmlns:xlink="http://www.w3.org/1999/xlink">q</sub>...

To enhance the power quality in medium/high-voltage distribution systems, a single-phase unified conditioner (UPQC) based on modular multilevel matrix converter (M3C) is presented this paper. The M3C-UPQC comprised of four identical arms and associated filtering inductors. According to established equivalent circuit M3C-UPQC, its operation principle balance each arm are analyzed theoretically, parameters' design for inductance as well submodule capacitance studied. Then, an integrated...