Current Issue

  • Stability analysis of PLL influenced by control loops in grid-connected converters under fault disturbance

    Abstract

      

    When the power grid suffers from grid faults that cause phase disturbances, the grid-connected converter becomes destabilized by the interaction between the phase-locked loop (PLL) and the control loop. In this paper, the stability of the PLL affected by the control loop under transient grid faults is studied. First, the equivalent model of the PLL under the influence of the control loop is establ...

  • Optimum control scheme of output voltage based on cascaded H-bridge DVR

    Abstract

      

    This study presents an optimum control scheme to maximize the output voltage level number of the cascaded H-bridge dynamic voltage restorer (CHB-DVR). The relationship between the modulation index and the output voltage level number is analyzed in detail. The compensation reference voltage value is adjusted with the voltage drop depth to obtain high-quality output voltage with an acceptable total ...

  • Use of voltage limits for current limitations in grid-forming converters

    Abstract

      

    Renewable generation interfaced through grid-forming converters are proposed as a replacement for synchronous generators in power systems. However, compared to the synchronous generator, the power electronics converter has a strict limit on the current to avoid overcurrent damage. The grid-forming converter acts like a voltage source, directily controlling the voltage. This conflicts with the oper...

  • Impedance modeling and stability analysis of a three-phase three-level NPC inverter connected to the grid

    Abstract

      

    The interaction between grid-connected inverters and the grid may cause stability issues, and compromise the reliable operation of the inverters. This study investigates the stability of a three-level neutral point clamped (NPC) inverter connected to the grid using impedance-based methods. Because the impedance model of a three-phase three-level NPC inverter has not yet been reported, this study f...

  • Impedance modeling and stability analysis of PV grid-connected inverter systems considering frequency coupling

    Abstract

      

    Impedance analysis is an effective method to analyze the oscillation issue associated with grid-connected photovoltaic systems. However, the existing impedance modeling of a grid-connected photovoltaic inverter usually only considers the effect of a single perturbation frequency, ignoring the coupling frequency response between the internal control loops of a grid-connected inverter, which severel...

Introduction

CSEEJPESThe articles published in this journal will focus on advanced concepts, technologies, methodologies and practices associated with all aspects concerning power and energy systems...
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