This paper presents a transformerless static synchronous compensator (STATCOM) system based on hybrid multilevel H-bridge converter with delta configuration. STATCOM is characterized by per-phase series connection of high-voltage operating at fundamental frequency and low-voltage 5 kHz without any other circuit for dc voltage control. A new control strategy proposed in this focus regulation. Clustered balancing realized injecting zero-sequence current to the delta-loop, while individual...

The trial and error method is the conventional for LCL parameter design. Its efficiency low it difficult to obtain optimal parameter. Furthermore, due lack of detailed analysis high-frequency harmonics in inverter output voltage, designed filter cannot effectively them, resulting that quality grid-connected current fully meet IEEE 519 standard. Based on above-mentioned problems, voltage analyzed detail this article, multiobjective optimization function, including five objectives,...

The paper presents the application of delta-connected cascaded H-bridge multilevel static var generator (SVG) under unbalanced compensation currents or supply voltages. Clustered balancing control for SVG can be realized by injecting a zero-sequence current to delta loop. But injection may cause high peak phase which break converter switches. aim this is analyze key factors that affect maximum output with and acquire quantitative relationship among unbalance capability, degree voltage,...

The high-power non-isolated three-level inverters face challenges related to switching loss, leakage current suppression, and controlling the Neutral Point (NP) potential. This paper aims address these issues by analyzing mechanism of generation, developing a loss reduction strategy, identifying factors that influence NP Given existing modulation algorithms fail account for all three control objectives simultaneously, this proposes new strategy called Loss Reduction-Improved Large Medium...

Carrier overlapping pulse width modulation (COPWM) is proposed to address the level degradation issue in carrier-based (CBPWM) at low index. Due its unique frequency multiplication band, COPWM has widespread application industrial scenarios where long-term operation index required. Similarly, space vector (SVPWM) exhibits more switching states index, and output performance can be enhanced by increasing number of segments. Numerous literature studies have analyzed equivalence relationship...

With the rapid development of power electronics dominated systems, impact supraharmonics generated by electronic devices on quality is becoming more and significant, leading to a new type problem that cannot be ignored. Current research focuses generation mechanism, propagation interaction effects, measurement standardization, but no effective suppression scheme for has been proposed so far. This paper proposes hybrid filter suitable dealing with in low-voltage distribution networks, which...

In the medium- and high-power grid-connected photovoltaic systems, controller bandwidth is constrained due to low switching frequency. This issue limits resonant frequency of traditional proportional multiresonant (PMR) then makes it difficult suppress main low-frequency harmonics in current. addition, for PMR maintain good performance under severe operating conditions, such as grid voltage containing resonant-frequency harmonic sagging. Based on abovementioned practical problems on-site...

We have investigated the magnetoelectric effect of a series Y-type hexaferrite Ba0.8Sr1.2Co2Fe11.1−xAl0.9CrxO22 (x ≤ 0.4) at room temperature. Although voltage coefficient αE these multiferroic hexaferrites is not high, it changes rapidly with an applied DC magnetic field, phenomenon known as giant magnetotranstance (GMT) effect. It found that GMT enhanced increasing content Cr and reaches maximum for x = 0.2. Specifically, ratio in 0.2 sample high −96% 2000 Oe −84% 500 Oe. Further addition...

Transformerless three-level inverters have many advantages over two-level in photovoltaic (PV) systems. However, transformerless systems, except for the inherent unbalanced neutral voltage of inverter, leakage current also needs to be limited strictly. Concerning defects conventional common-mode (CMV) suppression methods, an improved LMSVM (ILMSVM) method is proposed. Unlike CMV method, ILMSVM no longer just abandons high small vectors limit range ±1/ <inline-formula...

For the grid-connected inverter system, sustained constant-amplitude oscillations often occur. At this time, current undergoes oscillation, and PWM process appears saturation nonlinearity (i.e. overmodulation). However, existing modeling methods cannot accurately model hard nonlinearity, thereby explaining phenomenon of oscillation. In paper, step function is used to represent accurate stroboscopic mapping three-phase system established, it strictly proved that in a fundamental period,...

In-depth study of the DC side voltage control star connection cascaded H-bridge multilevel static var generator has been made in this study. Moreover, a three-layer system established. The first layer is overall control. three phases A, B and C maintained constant through generating fundamental positive sequence active current. second balancing between phases. Through injecting zero into command, authors can redistribute three-phase power, order to maintain voltages balanced; method, fast...

Using hybrid lattice-Boltzmann molecular dynamics simulations, we investigate the flow-driven translocation of comb-like copolymer micelles through a nanochannel, in particular, making detailed comparison with formed by corresponding diblock copolymers. Our results demonstrate that critical flow flux copolymers is higher than copolymers, which more pronounced increasing side chain lengths or grafting densities, as evidenced free energy computed self-consistent field theory. work indicates...

To improve the power capacity of system, several inverters are usually used in parallel. At present, global space vector modulation (SVPWM) parallel has been studied. However, when more parallel, implementation SVPWM is very complicated and its calculation amount greatly increased. Carrier-based pulsewidth (CBPWM) simple to operate implement. The traditional study on equivalent relationship between CBPWM multilevel only applicable monotonically increasing or decreasing sequences half cycle....

Nowadays, hybrid cascade multilevel technology has attracted a increasing concern, especially in moderate-voltage and high-power applications. In this paper, design method about how to main circuits of active power filters(APF) with structure is proposed. Through careful research, the combination these H-bridge modules properly chosen number high-frequency reasonably selected. Simulation results validate rightness proposed method.

The classification of voltage sag sources is essential for the establishment controlling scheme and reasonable division responsibilities in sag-associated accidents. Existing methods classifying usually ignore interpretability model, are only dedicated to improving accuracy classification, which cannot provide a reliable basis users power enterprises. Therefore, this article proposes an effective interpretable method based on sequential trajectory feature learning Random Forest algorithm....

DC microgrid technology has undergone significant growth due to advancements in renewable energy power generation and control technologies. Despite their flexibility scalability, microgrids face vulnerability fault currents the presence of numerous electronic devices complex operating conditions. Control systems further complicate current behavior, leading potential malfunctions protection devices. Thus, additional research is necessary enhance relay microgrids. This paper presents a...