Implementation and comparison of droop control, virtual synchronous machine, and virtual oscillator control for parallel inverters in standalone microgrid

Abstract

Summary In recent times, renewable energy sources (RESs) have been potential alternatives over the conventional generation systems connected to the grid. The power electronic inverters are the principal media of interface for connecting the RESs to the utility grid system. This work is primarily focused on the comparative analysis of Droop, virtual synchronous machine (VSM), and virtual oscillator control (VOC) techniques for the parallel operated inverters in a standalone Microgrid (MG). Droop control emulates only the droop characteristics of synchronous machines such that the transient response of this controller is not significant. VSM imitates not only the droop characteristics of synchronous machines but also the swing equation. Therefore, VSM has a remarkable difference in the dynamic performance of the system. In droop and VSM, the feedback signals such as voltage and current are measured to calculate the averaged real and reactive powers. However, the VOC works on instantaneous feedback signals such that it achieves much faster synchronization and good power‐sharing. The philosophy of the proposed VOC is to control an inverter such that it emulates the behavior of a nonlinear dead‐zone oscillator. The performance analysis of the system with the aforementioned controllers has been studied based on MATLAB/Simulink and Opal‐RT digital simulation. From the comparative analysis, it is observed that the VOC gives a better performance compared to droop and VSM control. The experimental results show the efficacy of the proposed VOC control method.

Research on Improved Droop Control Strategy of Microsource Inverter Based on Internet of Things

“…e increase of voltage and power output in microgrid will lead to the increase of access power, and the output power of power supply will be insufficient, resulting in the decrease of frequency. e droop coefficient will be obtained to help the distributed generation increase the active power output, and the system frequency and load power consumption will decrease synchronously [11]. Finally, a new balance point C is determined, which is formed by the interaction between distributed generation and load to achieve a stable power balance, namely, f-P control [12].…”

“…e actual output power of the inverter with the same capacity can be calculated by equation (11), which can be obtained according to the droop control principle of virtual power:…”

­­­Power Flow Management in MSSA Optimized Hybrid Fuzzy Integrated 3-DOF FOPID Controller-Based Hybrid Microgrid with Autonomous Bus Voltage Restoration

“…A grid-connected hybrid dc-ac microgrid utilising a photovoltaic (PV)-based dc-dc converter, a bidirectional Lithium Battery (LB)-based dc-dc converter, and a grid-connected dc-ac converter is regulated by various linear compensators embedded in the inner dynamics of the utilised power converters 12,13 . Energy management in a hybrid microgrid is discussed in detail by Kumar et al 14 , who conduct real-time and experimental study of the system. Gurugubelli et al 15 and Toghani et al 16 discussed on an energy management controller can easily control the charging and discharging of the energy storage system.…”

Virtual oscillator‐based methods for grid‐forming inverter control: A review

“…This section compares VOC and droop control. [39], [83][84][85][86] show that these two methods have wide applications in synchronization and power sharing between different inverters. [6] investigated the efficiency of droop-based controller as a voltage and frequency regulator in the GFM operation.…”