A new droop control method for the autonomous operation of distributed energy resource interface converters

Abstract

Microgrid is widely accepted as an effective mean of integrating various distributed energy resources (DERs) through their interface converters to provide electric power of high quality and reliability. These distributed resources interface converters (DICs) are required to operate in an autonomous fashion without any communication for enhanced reliability. Conventionally, the real power-frequency droop control and the reactive power-voltage droop are adopted as the de-centralized control strategies in these DICs for the autonomous power sharing operations. However, the reactive power sharing of Q-V droop control often deteriorates if there are mismatched transmission line impedance characteristics. In this paper, a Q-V dot droop control method with V dot restoration mechanism is proposed to improve the sharing of reactive power. Its operation principle and control method are explained and analyzed. In addition, simulation and experimental results are presented to validate the effectiveness of the proposed method.

An Enhanced Dual Droop Control Scheme for Resilient Active Power Sharing Among Paralleled Two-Stage Converters

“…Their combined effect is thus an improvement of the system dynamics. Increasing k p will however cause large frequency drop in the steady state according to the traditional droop expressions given in (1). Selection of k p should therefore be based on an acceptable trade-off between dynamics and steady-state drop.…”

“…may be inconvenient [1]- [4]. RESs are therefore prospective alternatives even though they are not likely to fully replace conventional generators.…”

Fixed-order decentralized/distributed control of islanded inverter-interfaced microgrids

“…A control strategy ubiquitously used for the control of microgrids is droop control which relies on the principle of power balance of a classical synchronous generator in conventional power networks (see, e.g., [5,6,7,8,9,10,2,11,12,13,14]). In the power systems based on rotating generators, frequency (rotor speed) is dependent on active power balance, i.e.…”

Optimal Design and Real Time Implementation of Autonomous Microgrid Including Active Load

“…Through droop control, emulating synchronous generators, sharing powers between inverter-based DGs was firstly proposed [6]. Droop control schemes with many advantages such as flexibility, redundancy, and expandability can be categorized for four main groups: (1) conventional and variants of the droop control [6,13]; (2) virtual framework structure-based method [14,15]; (3) "construct and compensate" based methods [16,17]; and (4) the hybrid droop/signal injection method [18,19]. The details and characters of various control schemes were illustrated in [5].…”