In this paper, a voltage modulated direct power control for three-phase pulsewidth rectifier is proposed. With the suggested method, differential equations describing dynamics are changing from linear time-varying system into time-invariant one. way, conventional feedback and feedforward controllers applicable independent of active reactive powers. The proposed method has guaranteed that closed globally exponentially stable. A linearization also employed generating reference inner loops....

In the rapid development process of a high-speed electrified railway, power quality problems in traction grid have become increasingly deteriorative. order to ensure three-phase balanced grid, modular multilevel converter based railway conditioner (RTPC) is presented. The RTPC consists four H-Bridge clusters and filter inductors, it can be directly connected feeders co-phase system without insulation transformers. According equivalent circuit analysis system, considered as single-phase...

Cascaded static synchronous compensator (STATCOM) is an effective solution for reactive power support in middle/high voltage conditions, and it has been widely employed to control photovoltaic (PV) plants, wind farms, industrial occasions. In this paper, strategy of cascaded delta-connected STATCOM under asymmetrical conditions investigated. A new phase current reference calculation method proposed continually abnormal considering cluster balancing limitation. Constrains between phasors are...

The dynamic performance of the local control single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this is based on droop principles, a proper calculation active and reactive averaged powers (P–Q) essential for proficient response against abrupt NLL changes. In work, VSI an was studied, focusing attention P–Q stage. This stage first generated direct in-quadrature signals from measured load current through second-order...

With the increasing application of synchronverter technology in renewable energy power generation, system stability issue becomes more complicated. Due to impedance interaction between based wind farm and series compensated transmission line, is prone cause sub-synchronous oscillation (SSO). To suppress this SSO, a generalized harmonic compensation control strategy active filter (APF) with supercapacitor proposed, which counteracts SSO by injecting current including reactive current. Since...

Nonlinear dynamical systems such as weakly coupled oscillators are an interesting approach to be adopted for the regulation of power inverters inside microgrids. Aiming at synchronization and load sharing in islanded mirogrid, this article is inspired by oscillator property propose a Hopf controller single-phase inverters. The dynamic equations used providing inverter's frequency amplitude voltage references, which lead robust nonlinear droop behavior driving system without using...

A simple high-performance decentralized controller based on Hopf oscillator is proposed for three-phase parallel voltage source inverter (VSI) in islanded Microgrid. In αβ frame, the oscillators equations corresponding output current and common bus as feedbacks are designed according to coupled synchronization properties. The enough information considered realize external synchronization, feedback achieve internal between VSIs. Then, employs evolution dynamics integrate their both....

The active and reactive powers, P Q, are crucial variables in the parallel operation of single-phase inverters using droop method, introducing proportional droops inverter output frequency voltage amplitude references. or P-Q, calculated as product its orthogonal version with current, respectively. However, when sharing nonlinear loads these Pav Qav, should be averaged by low-pass filters (LPFs) a very low cut-off to avoid high distortion induced loads. This forces method operate at dynamic...

This paper presents a method which mimics coupled nonlinear Poincaré-Bendixson oscillators synchronization to realize current sharing in islanded three-phase Microgrid. We propose that each inverter be controlled imitate the dynamics of oscillators. When they are interact strongly enough, will all start synchronization. also introduce comparison between Van der Pol oscillator corresponding their physical characteristics. The dual-loop based on is designed αβ frame, and phase derived observe...

In order to overcome the problems of power flow control and fault current limiting in multi-terminal high voltage direct (MTDC) grids, this paper proposes a modular DC controller (MM-DCPFC) with function. The topology structure, operation principle, equivalent circuit MM-DCPFC are introduced, such structure has advantages modularity scalability. balance mechanism is studied hierarchical strategy proposed. results show that can achieve internal exchange, which avoids use external supply....

This paper presents an adaptive synchronization for current-controlled grid-connected inverter based on a time-domain virtual oscillator controller (VOC). Inspired by the phenomenon of dynamics under perturbation effect. Firstly, fast learning rule frequency is derived in order to make evolve grid voltage. Thus realizing phase-locking behavior, but without requiring use dedicated phase-locked loop (PLL). Then, unit orthogonal components are obtained generate current reference, and designed...

The resonance problem in multi-paralleled grid-connected inverters microgrid is more complex than single one. Norton's equivalent circuit associated with inverter LCL filter figured out this paper. And terms of different reasons causing resonance, problems are categorized into three types: individual parallel series resonance. In order to attenuate peak, an active damping compensation term capacitor voltage feedback embedded current control forward path. proposed approach based on the...

In this paper, an improved grid voltage modulated control (GVM) with power compensation is proposed for grid-connected inverters when the unbalanced. The objective of to remove ripple and improve current quality. Three objectives are selected eliminate negative sequence components currents. modified GVM method designed obtain two separate second-order systems not only fast convergence rate instantaneous active reactive powers but also robust performance. addition, converts system into a...

The power calculation is an indispensable element in droop-controlled inverters because the bandwidth of measured has a direct impact on controller performance. This paper proposes fast and accurate algorithm based combined Second Order Generalized Integrator (SOGI) filters stationary coordinates for three-phase system, which takes into consideration use nonlinear loads. scheme formed by two-stage SOGI that are employed obtaining active reactive powers required to perform droop-based...

In this paper, an alternative realization method of droop control and virtual impedance for paralleled converters in DC microgrids is proposed as complement to the existing method. The major feature that behavior realized by using current reference together with a properly designed low-pass filter. Therefore, it will inherently get rid noise problem real-world measurement, which critical when realizing inductive components. addition that, impact filter used on dynamic performance also...

A novel coordinated control for energy storage system (ESS) and renewable source (RES) units is proposed in islanded AC microgrids without a phase-locked loop system. We use proportional-resonant technique the ESS, which fixes voltage frequency of microgrid. Moreover, we voltage-modulated direct power (VM-DPC) technique, has not only good tracking performance but also steady-state behavior, RESs that generate their maximum normal operation. To ensure stability microgrid, passivity property...

In this paper, the multi-mode operation of on-line UPS system is investigated and corresponding control strategies are proposed. The proposed able to achieve seamless transition in traditional normal mode, PV-aided enhanced eco-mode burn-in test mode. At same time, uninterruptible load voltage guaranteed during between these modes. Furthermore, stability mode studied by small signal analysis. Finally, extensive experimental results provided validate effectiveness methods.

A simple and fast decentralized Current-Voltage (I-V) droop control method under the Synchronous-Reference-Frame (SRF) is proposed to share output current for parallel three-phase inverters with LC filter. The I-V characteristic derived in accordance virtual impedance SRF. Thus, each inverter enables work a voltage controlled mode where it controls filter capacitor voltage. Moreover, detailed state-space model of two analyze performance. Through simulation experiment validation, provides...

Although virtual synchronous generator (VSG) is a promising solution to low inertia and damping of the power electronics-based system, improper parameter design will lead instability such system. In this paper, VSG strategy proposed by considering both AC DC restraints for paralleled inverters where active output restricted maximum limit converters in side, with energy supply bounded margin source side. Detailed stable operation boundaries are investigated using small-signal mode dual...

This work presents a literature review about control techniques for parallel connected power inverters under microgrid applications. Some strategies, based on droop of distributed generation units in an ac distribution system will be presented this work. Finally, important method called Virtual Oscillating Control (VOC) is suggested connecting voltage source inverters. Inverters are able to with constant-voltage constant frequency system, as well other and also standalone operation. The...