LCL filters offer a better choice of attenuating switching frequency harmonics. However, in grid-connected system, an filter may cause resonance which is disaster for the system's stability. In order to solve problem, two-current-loop control strategy, includes grid-current outer loop and filter-capacitor-current inner loop, adopted here. The implementation this strategy easy, but tuning procedure complex since controllers cannot cooperate well if parameters are not suitable. There no...

Under a short-circuit fault in low-voltage dc microgrid, solid-state circuit breaker (SSCB) assumes the responsibility of quick and effective isolation faulted area, while its own safety reliability depends on overvoltage suppression ability snubber. For SSCB snubber design, however, traditional method suited for converter switch cannot be directly applied, because stresses more current withstanding instead loss reduction. Therefore, this paper strives to build design specialized at bus...

Large disturbance scenarios, such as pulse power load operation and switching are commonly seen in the of dc microgrids. The mixed potential theory-based large-signal stability (LSS) analysis is a simple practical method for investigating LSS However, this characterized by conservatism, produces conservative criterion results. When they applied to parameter designs microgrids, create excessive control redundancies; when used running status estimations, may cause system be misjudged unstable,...

With the increase in large-scale renewable energy and DC transmission, synchronous generators power grids are gradually being replaced, resulting a continuous reduction inertia. The low-inertia system influenced frequency stability of grid. On one hand, knowledge inertia level is relevant to evaluate system. other anti-interference ability also relevant. Based on response mechanism conventional system, this study extended concept generator by introducing virtual proposed an evaluation method...

Since LCL filter has smaller inductance value comparing to L type with the same performance in harmonic suppression. It is gradually used high-power and low-frequency current-source-controlled grid-connected converters. However design of filter's parameter not only relates switch frequency ripple attenuation, but also impacts on current controller. This paper firstly introduced a model operation, then researched variable relationship among resonance high-frequency attenuation. Based above...

In this letter, the high-temperature performance of 4H-SiC avalanche photodiodes (APDs) working in Geiger mode is studied for first time. At unity gain bias, maximum quantum efficiency APD increases from 53.4% at 290 nm to 63.3% 295 as temperature rises room 150 °C. Meanwhile, dark current before breakdown by more than two three orders magnitude. a fixed 1.3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> , single photon counting...

Various new technologies for conversion between different forms of energy promote the appearance hybrid multi-carrier system. For purpose optimized dispatch and security requirement system, reliability this kind system needs to be discussed. This article proposes a method based on entropy-based Markov model analyze First, obtain individual carrier is Second, characteristic analyzed. The shown an effective technique whole depending carrier. Then, fusion process described. result indicates...

Although hybrid circuit breaker (HCB) uses a combination of mechanical switch and insulated-gate bipolar transistors (IGBTs) to accommodate HVDC application, it still has large number series-connected IGBTs in its main breaker. Besides, multiterminal system, three or more HCBs appear cluster at one node, which worsens the HCBs' disadvantage volume. To simplify cluster's topology structure control system as well increase compactness, multiport (MPCB) is proposed this paper with procedure...

To optimize the energy supply potential and complementary advantages of distributed energy, this paper focuses on dispatching optimization cogeneration virtual power plant considering uncertainty. First all, wind power, photovoltaic, combined heat (CHP) units, electric boilers, controllable loads are integrated into a CHP plant. Then, carbon capture electric-to-gas devices introduced to realize recycling. Furthermore, quantify risk real-time plants through uncertainty scenario generation...

An input-independent and output-series modular dc-dc converter with multiple input ports high voltage conversion ratio can apply well to medium-voltage dc interface of distributed photovoltaics (PV). However, PV power mismatch will result in output imbalance the submodules (SMs), which is contrary standardized multimodule design. In this article, a multiport low-loss series LC balancing unit (PBU) proposed address problem. isolated employed as SM, consists full-bridge (FB) circuit on side...

As the crucial interface of renewable energy integration, stable operation power converters under grid faults and external disturbances has become much more important. However, synchronization instability grid-tied inverters been found caused by phase-locked loop (PLL) some critical operating conditions, such as voltage sag, current surge, transmission line faults. Due to strong nonlinearity, transient stability analysis with PLL becomes complicated large-signal perturbations weak...

In order to improve the performance of traditional phase-shifted full-bridge converters and reduce output current ripple, an improved zero voltage switching PWM converter is proposed in this article. By adding a simple auxiliary circuit, leading-leg switches realize lagging-leg switching. The primary reset during freewheeling period, so efficiency improved. What more, can effectively ripple. added circuit does not include any lossy components or saturable reactors. has many advantages,...

In traditional DC distribution networks with both a low-voltage (LVDC) and medium-voltage (MVDC) bus, units are connected to the LVDC bus through converters. this approach no galvanic isolation is provided two power conversion stages needed between MVDC grid, hence leading high number of converters higher costs. To address these shortcomings, paper proposes novel multi-port solid-state transformer (MDCSST) interface directly bus. Multiple modules in series on medium voltage side whereas...

To construct the bipolar dc microgrid and maintain poles voltage balanced, usually a dedicated balancer (VB) is needed. In this article, general four-port converter with series <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> (LCVB) proposed to replace VB. The composed of two partial power processing dual-active bridges (PDABs) branch. branch added between outputs PDABs, which are combined half-bridge circuits form LCVB. Two PDAB inputs...

Compared with the solid-state circuit breakers based on insulated-gate bipolar transistor and MOSFET, thyristors have higher capacity lower cost, which been extensively studied. However, existing cannot achieve fast reliable shutoff of fault current. Therefore, a novel efficient bidirectional breaker is proposed in this article, has functions automatic controllable shutoff. In any current direction, only one thyristor conductive, eliminates unnecessary power losses. The function can cut off...

At the occurrence of a permanent fault in DC microgrid, apart from isolating faulty section using solid-state circuit breaker, protection system should also have position located so that repair crew can be sent to clear and restore isolated section. Available location methods are either influenced by network topology or need add costly equipment. Located immediately next line, breaker has advantage required for injecting detecting signals, it is rest disconnector after interruption....

A multiport dc/dc converter with cascaded submodules (SMs) can be employed in a photovoltaic (PV) power generation system for its high step-up ratio. Consisting of multiple low-voltage (LV) input ports and one high-voltage (HV) output port, the is more likely to suffer short-circuit faults than two-port converter. To ensure reliable operation converter, fault-tolerant capability should necessarily considered. In this article, topology PV proposed satisfy requirements fault tolerance ability....

To realize a soft-switching inverter with small volume and high efficiency, synchronous auxiliary resonant commutated pole (SARCP) improved load adaptability is proposed, which only contains two inductors. In one switching cycle, all commutation processes can be synchronously assisted by an inductor. Soft achievable for switches of the SARCP inverter. Compared (ARCP) inverter, has adaptability, especially in light current condition, beneficial to reduce total power loss dc-link capacitance....

DC-DC converters with output-series cascaded submodules (SMs) are required for the medium-voltage direct current (MVDC) grid interface of photovoltaic (PV) systems. However, mismatched power PV arrays can cause an imbalance among output voltages SMs. In order to address this problem, in paper, a multi-port converter is established on basis voltage balancer (VB) novel feedforward voltage-balancing control strategy. The has multiple input terminals and terminal connected MVDC grid....

Single-phase single-stage nonisolated photovoltaic (PV) grid-tied inverters mainly suffer from issues of the common-mode leakage current and double-line-frequency power oscillation. Aiming to address these issues, this article designs a new single-phase PV inverter with only two switches. The structure proposed allows neutral line alternating (ac) grid be directly connected negative pole panel so that can completely eliminated. Additionally, decoupling method is suppress Then an improved...