In recent years, the increasing penetration of distributed generation in microgrids challenges control and coordination energy resources. Especially with virtual synchronous generator (VSG)-controlled converters conventional generators (SG), inherent inertia difference (i.e., VSG SG) results a poor transient performance when and/or loads are cut in/out. Thus, this paper explores parallel SG systems. More importantly, novel pre-synchronization method is proposed to eliminate phase jump while...

The grid-connected inverter with virtual synchronous generator (VSG) control technology can improve the friendliness of a distributed power supply to grid. However, its low-voltage ridethrough (LVRT) capability is insufficient, which results in difficulties limiting current and provide reactive support. A new LVRT strategy based on smooth switching proposed this paper. In strategy, voltage source mode VSG transformed into limit output support through proportional resonance algorithm under...

The application of virtual synchronous generators in the power system eases pressure on grid caused by penetration lots electronic devices, but worsens dynamic frequency stability grid. Meanwhile, order to solve problem coupling low-voltage micro-grid systems, most measures introduced impedance technology adjust equivalent output system. Therefore, studies have adopted adaptive control strategy moment inertia, improve adjustment However, it will cause response speed reduction problem. In...

Virtual synchronous generator (VSG) possesses the advantage of friendly interaction with power grid by simulating characteristics. However, its low‐voltage ride through (LVRT) capability is insufficient. The excessive output current VSG easily causes wind turbines to break away from grid, which will exacerbate negative impact fault. Thus, a new LVRT control strategy proposed based on analysis excitation state for VSG. droop characteristic, reactive loop and active are improved, respectively,...

Active power oscillations and frequency fluctuations appear simultaneously in virtual synchronous generator (VSG) systems with fixed rotor inertia damping coefficients. Thus, an optimisation control strategy to self-adjust the parameters is proposed this study suppress fluctuations. A small-signal model of parallel VSG established, impact coefficients on output active analysed. Then, parameter for self-adjusting introduced according rate change deviation electrical angular velocity. Notably,...

The impedance of the virtual synchronous generator (VSG) is an effective method to analyze dynamic interactions between VSG and grid. For existence power controllers asymmetric inner-loop in d- q-axis, there are couplings output sequence VSG. Although relatively small, they still have a significant impact on stability performance. However, no result published this aspect up now. To bridge gap, model based harmonic linearization established paper, which explicitly reveals mirror frequency...

In allusion to the virtual synchronous generator (VSG)-based voltage source inverters in micro-grids, an integrated control method combining a quasi-synchronization algorithm and islanding detection is proposed improve power supply reliability quality, which can simultaneously meet operational requirements of both grid-connected mode (GCM) off-grid (OGM), smooth switching between them. The micro-grid inverter designed realize flexible grid connection. Moreover, for quickly detecting...

Insufficient inertia is one of the urgent problems to be solved in stability AC-DC hybrid microgrid. In order improve AC bus frequency and DC voltage microgrid, a virtual control strategy for bidirectional interface converter (BIC) based on synchronous generator (VSG) proposed. The equations both sides are used slow down variation frequency. When load fluctuates, dynamic response voltage, power transmission between subnets improved, thus improving system. This enables BICs share active...

Dual rotor permanent magnet (DRPM) wind power generator using ferrite magnets has the advantages of low cost, high efficiency, and torque density. How to further improve performance reduce cost machine by proper choice pole number slot is an important problem be solved when performing preliminarily design a DRPM generator. This paper presents comprehensive comparison with different combinations. The main winding factors are calculated means star slots. Under same volume consumption, flux...

This paper proposes a five-degree-of-freedom (5-DOF) hybrid magnetic bearing (HMB) for direct-drive wind turbines, which can realize suspension in the 4-DOF radial and 1-DOF axial directions. Only two sets of control windings are employed proposed HMB because only one set achieve 2-DOF direction. Unlike traditional active thrust bearings, this uses cylindrical rotor core without large disc novel HMB. The numbers controller, power amplifier system volume be reduced system. also presents...

The flux-switching permanent magnet (FSPM) machine is widely investigated due to the advantages such as ease of PM heat management, simple and robust structure rotor, high power density torque density, sinusoidal back electromotive force (EMF) fault-tolerance capability. purpose this paper propose a C-core linear FSPM for ropeless elevator, in which two positive additional teeth are employed at each end primary side reduce asymmetry caused by effect. Firstly, proposed presented. Then...

In order to broaden the limited utilization range of wind power and improve charging discharging control performance storage battery in traditional small generation systems, a system based on vertical-axis off-grid induction generator is proposed this paper. The not only can run wide speed but also assist turbine realize self-starting at low speed. Combined with maximum point tracking method, slip frequency strategy employed regulate pulse width modulation (PWM) converter output when load...

Aiming at the problems of poor dynamic characteristics and low power distribution accuracy paralleled bi-directional interface converters (BICs) in hybrid AC-DC microgrids, a generalized DC electromotive force (G-DCEMF) control strategy suitable for parallel BICs is proposed this paper. This not only enables to share active equally under stable conditions, but also have external motor. When load changes, can suppress fluctuation bus voltage, reduce influence change on AC frequency, improve...

This paper presents a comprehensive analytical model for dual rotor radial flux wind generators based on the equivalent magnetic circuit method. is developed to predict densities of inner and outer air gaps, stator yokes, back electromotive force (EMF), electromagnetic torque, cogging some other characteristics important generator design. The 2D finite element method (FEM) employed verify presented model, fine-tune it, validate prediction precision. results show that errors between proposed...

This paper investigates the design and analysis of a dual-rotor radial flux permanent-magnet (DRRFPM) generator. The key parameters DRRFPM generator are studied to achieve best performance. split ratio inner stator diameter outer is optimized take full advantage internal space machine. polar arc coefficient discussed minimize cogging torque ensure sinusoidal waveform EMF. slot opening angular width also considered reduce torque. optimal carried out by finite element (FEA). simulation results...

Analysis on operation characteristics of dual stator-winding induction generator (DWIG) wind power system under asymmetrical grid faults is elaborated in detail the paper. The output dc voltage maintained steady by rapid flux-weakening control static excitation controller (SEC) control-winding side. Fault ride through achieved restraining input from side and avoiding fluctuations with 2 times frequency during asymmetric happen. Simulation results prove that DWIG has strong fault-ride-through...

This paper analyzes the demagnetization performance of ferrite Permanent Magnets in dual rotor radial flux permanent magnet generator.Two different partial mechanisms DRRFPM generator are modeled and demonstrated.The 2D finite element analysis (FEA) is employed to accurately analyze distribution demagnetization.The FEA results for proposed verify validity model.The degradation induced by evaluated based on results.This research reveals most vulnerable region irreversible generator.