Large-scale renewable energy bases in desert regions often feature extensive scale, wide geographical distribution, weak grid infrastructure, distance from load centers, and lack of conventional power support. Traditional planning operation methods are no longer suitable for large-scale transmission scenarios. Therefore, focusing on regions, this study proposes a time series production simulation model aimed at maximizing output the sending terminal via flexible DC transmission. Based actual...

Many renewable energy resources are integrated into power systems via grid-following (GFL) inverters which rely on a phase-locked loop (PLL) for grid synchronization. During severe faults, GFL vulnerable to transient instability, often leading disconnection from the grid. This paper aims elucidate interaction mechanisms and define stability boundaries of two inverters, including GFL, grid-forming (GFM), or grid-supporting (GSP) inverters. First, generalized large-signal expression...

Following the continuous development of wide bandgap (WBG) devices and multilevel converter technology, medium voltage active front ends are becoming promising in future high-power-density high-power applications. However, cost issue is one major drawbacks, which stops WBG from being widely applied areas. This article proposes a silicon carbide (SiC) (Si) hybrid five-level unidirectional rectifier. It requires only four SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Impedance measurement techniques based on small-signal injections in ac power system have been well developed but a gap the analysis is that selection of an injection amplitude only experience. This letter develops analytical process to analyze noise existing systems and thereby determines minimum according allowable error. The knowledge stochastic processes statistics, where Monte Carlo method also employed simplify process. A hardware-in-the-loop with grid-following inverter experimental...

Fuzz testing technology is an important approach to detecting SQL injection vulnerabilities. Among them, coverage-guided gray-box fuzz the current research focus, and has been proved be effective method. However, for vulnerability, as a detection method problems of low efficiency high false positives. In order solve above problems, we propose potentially vulnerable code-guided technology. Firstly, taint analysis used locate all propagation paths containing potential vulnerabilities codes....

This paper proposes a fast load transient control for bidirectional dual-active-bridge (DAB) DC/DC converter. It is capable of maintaining voltage–time balance during step change process so that no overshoot current and DC offset exist. The has been applied all possible transition cases the calculation intermediate switching angles referring to fixed reference points independent from converter parameters instantaneous current. results have validated by extended experimental tests.

Application of functionally graded materials (dielectric with spatial variated permittivity or conductivity distribution) is a promising approach for the electric field optimization in cable accessories. In this paper, we uses multi-layer to design and distribution joint insulation, which are intended be applied AC DC applications, respectively. The results shows that intensification phenomena were inhibited after process. Moreover, degree E-field affected by permittivity/conductivity range,...

High speed drive system desires power converters with higher switching frequency to minimize the torque ripple and obtain a faster control capability. Silicon carbide (SiC) devices based have gained increasing attention in such applications due their extraordinary performance. Possible solutions including two-level converters, three-level hybrid comprising both Si SiC device. In this paper, comprehensive comparison of possible high density is given. Simple calculations show that an...

With the continuous advancement of China's social development and energy structure adjustment, HVDC technology has outstanding advantages in breaking uneven distribution regional resources, easing bottleneck resource utilization improving efficiency operation. However, commutation failure inverter side multi-infeed DC system is easy to cause failure. Dynamic reactive power compensation device(DRPCD) can effectively provide support reduce risk In order restrain system, this paper proposes an...

Accurate evaluation of the treatment result on X-ray images is a significant and challenging step in root canal therapy since incorrect interpretation results will hamper timely follow-up which crucial to patients' outcome. Nowadays, performed manual manner, time-consuming, subjective, error-prone. In this paper, we aim automate process by leveraging advances computer vision artificial intelligence, provide an objective accurate method for assessment. A novel anatomy-guided multi-branch...

Abstract The wireless energy transmission technology is utilized in the integrated primer fuze device to achieve of and information for weapon equipment. A system model designed specifically characteristics priming fuze. working principle under S-P magnetic coupling resonance analyzed, inverter circuit rectifier are further designed. To synchronous information, an modulation/demodulation method based on FSK proposed. Simulation verifies feasibility design, showing that while has a simple...

The application of centrifugal compressors is extensive in industries such as aerospace and energy. blade the primary factor affecting aerodynamic performance compressors. In this paper, a compressor with leaned bowed 3D blades investigated. spanwise section profiles circumferential direction are deflected at different angles, resulting four distinct based on original model. There significant change isentropic efficiency modified models under design conditions. Specifically, 1, 3, 4...

The high-order harmonic generally occurred in the connected transformer under practical operation condition which will cause nonuniform heating and bring unexpected hazard. In this study, to analysis thermal field distribution, a 3D finite element model of is established. magnetic flux iron core, leakage tank wall frame clamps were calculated. Also, distribution hot spot temperature core has been calculated using magnetic-thermal coupling method. results indicated that, when occurred, both...

This study considers the state-of-charge estimation for lithium-ion battery in low-cost portable applications where current measurement is presumed unknown. By regrading as an unknown input, this problem reformulated optimal filtering of nonlinear systems with input. A novel unscented recursive three-step filter then proposed to simultaneously realize SOC and estimation. The transformation utilized obtain mean covariance system state. Evaluation approach made by experiments under two...

With the continuous advancement of wide bandgap devices and development multilevel technology, medium voltage high power active front ends (AFE) are becoming more attractive in many areas, especially UPS system for data center. In order to further improve density AFE also keep relatively low cost, a SiC & Si hybrid five-level unidirectional rectifier is proposed which requires only four MOSFETs with blocking voltage. Meanwhile, all low-speed switching. Firstly, merits illustrated. Then,...

The multilevel active-neutral-point-clamped (ANPC) topology with more control freedom has been widely used in medium-voltage and high-power areas. SiC MOSFET Si device hybrid ANPC converter a relatively low price can further increase power density efficiency. In this paper, generalized construction method for is proposed, which includes the definition of basic cells, criteria that enable structure special steps generate topologies. Based on it, series converters are derived. addition,...

Aiming at the issue of wind power curtailment, with goal improving its absorption capacity and green-friendly grid connection, a wind-hydrogen coupling system model control strategy are proposed.. A DC bus structure electrolyzer fuel cell is constructed, mathematical models direct drive turbine, established. The coordinated as follows: when output greater than load demand, residual hydrogen production by electrolyzing water in will be absorbed; When less supplement balance; In case...

Electric vehicles have gradually become the mainstream means of transportation. As a way energy storage, electric can participate in flexible regulation grid frequency. However, when great quantity are connected to grid, stability power system will be affected. On one hand, grid-forming output active they frequency modulation is introduced. other inertia adjustment strategy applied control vehicles, which limits change rate inverters and optimizes dynamic characteristics. Finally, an example...

During the fault ride-through process of MMC-HVDC system for grid-connected offshore wind farm, unloading circuit does not start to function until DC voltage reaches a certain value period time, which results in great impact on sub-module land side, there is risk damaging electronic components, this paper, control strategy improved according characteristics during fault, and suppressed under premise ensuring performance. Finally, semi-physical simulation model pseudo-bipolar flexible HVDC...