Partially Rated Power Flow Control Converter Modeling for Low Voltage DC Grids

Scalable and robust low-voltage direct current (LVdc) distribution networks require solutions, allowing flexible power flow control and reliable short-circuit protection. In this paper, the continuous full-order large-and small-signal models of a partially rated power flow control converter (PFCC) are derived utilizing the generalized...

Output Impedance Modelling and Sensitivity Study of Grid-Feeding Inverters with Dual Current Control

In this paper, the output impedance of a three-phase inverter based on a dual current control (also called double synchronous reference frame current control) is modelled, which includes: the current loop gain, the control delay, and the Phase-<br/>Locked Loop (PLL). The impact of these parameters on the impedance is then analysed by a...

Decoupling Control of Multiactive Bridge Converters Using Linear Active Disturbance Rejection

Multiactive bridge (MAB) converter is a promising solution for integrating multiple renewable sources, storage, and loads for various applications. However, the MAB converter is challenging to control due to the inherent coupling between the port power flows. To that end, this article presents a decoupling control strategy based on linear...

Power Flow Decoupling Controller for Triple Active Bridge Based on Fourier Decomposition of Transformer Currents

This paper proposes a power flows decoupling controller for the triple active bridge converter. The controller is based on a full-order continuous-time model of the TAB converter derived using the generalized average modelling (GAM) technique. GAM uses the Fourier series expansion to decompose the state-space variables into two components,...

On the Importance of Tracking the Negative-Sequence Phase-Angle in Three-Phase Inverters with Double Synchronous Reference Frame Current Control

A voltage imbalance at the AC terminals of a three-phase inverter creates a ripple in the power signal on the DC side. In order to minimize this ripple, several techniques can be applied, in which a double Synchronous Reference Frame (SRF) current control structure is very typical. In this approach, both the positive and negative sequence...

Coordination Control of Power Flow Controller and Hybrid DC Circuit Breaker in MVDC Distribution Networks

The two main challenges of medium voltage direct current (MVDC) distribution network are the flexible control of power flow (PF) and fault protection. In this paper, the power flow controller (PFC) is introduced to regulate the PF and inhibit the fault current during the DC fault. The coordination strategy of series-parallel PFC (SP-PFC) and...

An Adaptive Cyber Security Scheme for AC Microgrids

Distributed secondary control is deemed necessary to restore the state of AC micro-grids to set points. However, for its limited global information, the power electronic system is vulnerable to cyber-attacks that aim to desynchronize converters or even cause a shutdown of micro-grids by unnecessarily triggering the protection schemes. To this...

Power Disequilibrium Suppression in Bipolar DC Distribution Grids By Using A Series-Parallel Power Flow Controller

The unbalanced power between positive and negative poles in a bipolar DC distribution network (DC-DN) generates an unbalanced current at the neutral line, which enlarges the power losses of the system and the voltage deviation of DC loads. An unbalanced power suppression strategy based on a series-parallel power flow controller (SP-PFC) is...

An Adaptive Virtual Impedance Control for Reactive Power Sharing in Microgrids

In multi-inverter parallel connected islanded micro-grids, reactive power sharing is challenged by the differences in feeder impedance and various controller parameters. In order to address this issue, a virtual impedance reshaping strategy based on the consensus algorithm is proposed in this paper. The proposed method facilitates adaptive...

Stability Enhanced Design of EV Chargers for Weak Grid Connection

Reinforcement of the legacy grid infrastructure will be very costly and thereby unrealistic. Consequently, weak grid connection of electric vehicle (EV) chargers will sooner or later be the case. It may however bring instability issues since the EV chargers that can work well in strong grid conditions usually do not fit the weak grid...

Virtual Impedance Control for Load Sharing and Bus Voltage Quality Improvement

This paper proposes a virtual impedance reshaping strategy to share active and harmonic power while promoting the PCC voltage quality. Moreover, the suggested method is resilient to cyber-attacks and immune to communication interruption and delay. Furthermore, it significantly reduces the communication burden. Experiments verify the...

Critical Short Circuit Ratio of an EV Charging System

The critical short circuit ratio (CSCR), as an important metric for grid stability evaluation, is not clearly defined in the literature. Aimed at clarifying the misunderstandings, the paper compares the different CSCR definitions. Moreover, CSCR reduction-oriented design is studied for electric vehicle chargers. Simulations verify the analysis.

A Resilience Enhanced Secondary Control for AC Micro-grids

Communication-based distributed secondary control is deemed necessary to restore the state of islanding AC microgrids to set points. As its limited global information, the microgrids become vulnerable to cyber-attacks, which by falsifying the communicating singles, like the angular frequency, can disturb the power dispatch in the microgrids...