It is well known that conventional two-level pulsewidth modulated (PWM) inverters generate high-frequency common-mode voltages with high dv/dt. Similarly, commonly used multilevel inverter modulation schemes voltages. Common-mode may cause motor shaft and bearing currents conducted electromagnetic interference (EMI). Premature failures electronic equipment malfunctions have been reported to be directly related EMI. In this paper, approaches eliminating voltage when using PWM are presented....

During voltage dips continuous power delivery from distributed generation systems to the grid is desirable for purpose of support. In order facilitate control inverter-based adapted expected change requirements, generalized strategies based on symmetric-sequence components are proposed in this paper, aiming manipulate delivered instantaneous under unbalanced dips. It shown that active and reactive can be independently controlled with two individually adaptable parameters. By changing these...

Solid-state transformer (SST) has been regarded as one of the most important emerging technologies for traction system and smart grid application. This paper presents design performance demonstration a high-voltage SST lab prototype that works active interface in architecture. Specifically, designs key components system, including both power stage controller platform, are presented. In addition, advanced control is developed to achieve high-performance operation. Furthermore, integration...

This paper proposes an impedance-based analytical method for modeling and analysis of harmonic interactions between the grid aggregated distributed generation (DG) inverters. The root cause interaction/resonance problems is impedance-network quasi-resonance effective output impedance inverter equivalent at connection point. Starting with inverter, a Norton model derived. Comparing switching average simulation results show effectiveness model. that limits should be specified used as extra...

The adoption of the virtual synchronous generator (VSG) has attracted wide attention because equivalent operating mechanism as a generator, providing feasible scheme for distributed generation connected to utility grid. However, delivered power and frequency VSG may easily oscillate when dramatic fluctuation occurred in distribution system. Fortunately, oscillation can be damped though adjusting rotating inertia damping coefficient. Thus, investigate influences parameters perturbation on...

This paper provides a comprehensive overview of the microgrid (MG) concept, including its definitions, challenges, advantages, components, structures, communication systems, and control methods, focusing on low-bandwidth (LB), wireless (WL), wired approaches. Generally, an MG is small-scale power grid comprising local/common loads, energy storage devices, distributed resources (DERs), operating in both islanded grid-tied modes. MGs are instrumental to current future electricity network...

This paper studies the inherent relations between sine-triangle and space-vector pulsewidth modulation schemes for three-level voltage-source inverters. It is shown that two can function equivalently through proper selection of common-mode injections in case modulation, or dwell times equivalent redundant switching states modulation. Simulation measurement results illustrate understanding these lead to a more efficient flexible modulator with desired optimal performance.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> When the wind power accounts for a large portion of grid power, it may need to help voltage and frequency regulation. This paper investigates permanent-magnet generator with full voltage-source converter in weak-grid mode, where dc-link needs be controlled from side instead side. The energy relationship generator, storage, load is established. An intrinsic right-half-plane zero, together...

Grid-interfacing converter systems with enhanced voltage quality are proposed for microgrid applications in this paper. By adapting the conventional series–parallel structure, a group of grid-interfacing system topologies purpose interfacing local generation/microgrid to grid, or interconnecting microgrids. The functionality is also reconfigured order ease control design and improve overall performance, differing from existing structure-based systems. Experiments concrete laboratory given...

A crucial component of grid-connected converters is the phase-locked loop (PLL) control subsystem that tracks grid voltage's frequency and phase angle. Therefore, accurate fast-responding PLLs for protection purposes are required to provide these measurements. This paper proposes a novel feedback mechanism single-phase PLL detectors using estimated Ripple noise appearing in frequency, most commonly second harmonic under phase-lock conditions, reduced or eliminated without use low-pass...

A voltage balancer that transfers unipolar dc bus configuration to bipolar has been widely employed in microgrid. Fortunately, unbalanced power flow between positive and negative buses can be eliminated through a well-designed balancer. Based on the analysis of Buck/Boost-type balancer, deduction method for series balancers is proposed this paper, further investigated by applying other existing balancers. Consequently, several new topologies are various purpose improvement with respect...

As the power of wind energy system increases, control their active and reactive becomes increasingly more important from a standpoint given that these are typical frequency voltage parameters. In this paper, family systems with integrated functions transfer, compensation, conversion is proposed. The proposed using solid-state transformer (SST) can effectively suppress fluctuation caused by transient nature without additional compensator and, as such, may enable large penetration farm (WF)...

This paper comprehensively investigates and compares different multiloop linear control schemes for single-phase pulsewidth modulation inverters, both in stationary synchronous (d –q) frames, by focusing on their steady-state error under loading conditions. Specifically, it is shown how proportional plus resonant (P + R) load current feedback (LCF) can, respectively, improve the transient performance of inverter, leading to proposal a PID R LCF scheme. Furthermore, capacitive are be subject...

Small-signal stability is an important concern in three-phase inverter-based ac power systems. The impedance-based approach based on the generalized Nyquist criterion (GNC) can analyze related with medium and high-frequency modes of However,. GNC involves right-half-plane (RHP) pole calculation return-ratio transfer function matrices, which cannot be avoided for analysis complicated Therefore, it necessitates detailed internal control information inverters, not normally available commercial...

This paper presents test results on problems and solutions of motor shaft voltages bearing currents in medium-voltage pulsewidth modulated (PWM) drive systems. Tests show that multilevel PWM voltage-source inverter drives can cause currents, similar to a low-voltage drives, even with one insulated. Common-mode generated as result switching are observed windings capacitively coupled the shaft, leading currents. Potential solutions, including altering common-mode circuitry, changing grounding...

This paper presents a complete design methodology for the sensorless vector control of permanent-magnet synchronous machine (PMSM) motor drives in fan-type applications. The proposed strategy is built over linear asymptotic state observer used to estimate PMSM back EMF and novel tracking controller based on phase-locked loop system, which, by synchronizing estimated actual <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML"...

The three-phase pulsewidth-modulation (PWM) converter is one of the most widely used topologies for power conversion. In order to design PWM methods, influence methods on current ripple needed. This paper studies a with general and control this kind converter. analyzed eight different Thevenin equivalent circuits voltage vectors. Then, current-ripple slope effective time could be achieved every period. predicted both peak rms values. Analytical results show that discontinuous generate...

This paper presents the design and hardware implementation testing of 20kVA Gen-1 silicon based solid state transformer (SST), high input voltage isolation requirement are two major concerns for SST design. So a 6.5kV 25A dual IGBT module has been customized packaged specially this low current application, an optically coupled sensor gate driver designed in order to fulfill requirement. also discusses auxiliary power supply structure thermal management stage.

This paper proposes a novel circulating-current control strategy applied in back-to-back parallel three-phase converters with individual dc links for permanent magnet synchronous motor (PMSM) drives. First, the zero-sequence circulating current and cross paths whole system are analyzed. Then, models of an n-paralleled subsystem both stationary coordinates rotating built up, which explores fundamental mechanism current. Based on analysis, can suppress at side. The consists two main loops...

This paper presents the development of a distribution network solid state transformer (SST) based on high voltage (13kV) SiC MOSFET and JBS diode. SST is composed with medium ac/dc rectifier, frequency dc/dc converter low inverter. It's able to be interfaced 3.6kV grid output both 400V dc 240/120V ac. characterization devices, design rectifier converter. The test results its grid-connected operation including pre-charge, start up, regeneration, etc. are included show functionalities designed...

Due to the capacity limitation and renewable energy's uncontrollability, multiple energy hubs (EHs) are connected by routers (ERs) form a network structure further build future internet. With concave objective functions and/or nonlinear operation constraints, centralized optimal dispatch of interconnected EHs is difficult solve. In order reduce complexity on large-scale systems protect information privacy different EHs, hierarchical optimization strategy put forward for ER-based...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper proposes a new frequency-domain modular-terminal-behavioral (MTB) modeling approach for characterizing conducted electromagnetic interference (EMI) noise sources in converter. It models the EMI emission of switching device module under specific conditions using three-terminal equivalent Norton network, which can be extracted from standard test. Experiments show that MTB model used to...

With the increasing demand of different voltage levels in industrial applications, multiport dc–dc converters have been widely employed owing to their low-cost merits. Aiming provide more topologies so that engineers can select out a preferred one for specified application, this article proposes novel principle systematically implement topology derivation by replacing switches original with pulsating current source cells. This is simple and effective, which multiple new integrated having low...

The bridgeless power factor correction (PFC) converter is popular for reducing the conduction losses of semiconductors. In this article, a novel Cuk PFC proposed. Compared with conventional converter, number conducting semiconductors in proposed reduced, contributing to lower losses. Moreover, are further improved compared pseudototem-pole converter. Meanwhile, total component less than other counterparts, especially big-volume magnetic and electrolytic capacitor. addition, all switches...

For system planning of three-phase inverter-based islanded ac microgrids, the low frequency instability issue caused by interactions inverter droop controllers is a major concern. When internal control information procured commercial inverters unknown, impedance-based small-signal stability criteria facilitate prediction resonances in medium and high ranges, but they usually assume grid fundamental as constant thus are incapable analyzing low-frequency oscillation microgrids. Aiming at...