A Grid Synchronization Method for Droop-Controlled Distributed Energy Resource Converters

Abstract

The microgrid is a very effective way of integrating various distributed generation resources into the ac power system. To provide electric power of high reliability, the converters in the microgrid often rely on autonomous droop control methods to reduce their dependence on communication and need to operate in both the islanded mode and the grid-connected mode. In this paper, a grid synchronization method for a multiconverter distributed generation system is proposed. The proposed grid synchronization method allows multiple droop-controlled converters to adjust the frequency, phase, and amplitude of their output voltages to prepare for grid connection. The entire synchronization process can be executed with very limited communication requirement. This paper provides detailed explanation on the proposed grid synchronization method. Experimental test results are presented to validate the effectiveness of the proposed method.

Dynamic Responses Improvement of Grid Connected WPGS Using FLC in High Wind Speeds

“…A bridge rectifier provides AC to DC and then DC link voltage using PI controller to obtain constant value, then DC voltage will be inverted to get desired AC voltage [20].…”

“…In recent years, many topologies based on power electronic devices with different level of complexity and cost is developed investigated in order to connect a PMSG to network. There are two modes for inverter operating: 1) Active and reactive control mode (P-Q control), 2) Voltage and frequency control mode (V-F control) [19,20].…”

An Effective Control Strategy for Optimising Critical Load Power During Uncertainities in Microgrid

“…Here various DGs are combined especially Renewable Energy Sources(RES).In case of emergency this is having capability to change between grid tied mode and islanded mode [3]. The issues related with Microgrids are Synchronization of these micro grids with main grid voltage vector which sometimes easily become unbalanced and distorted due to the effect of faults and nonlinear loads [4], Control of active and reactive power, Direct connection of Microgrid with grid is not possible, Instability and less reliability during grid tied mode, power cannot be continuously supplied with relays during the conversion of islanded mode to grid tied mode and vice versa, Improper charging and discharging of battery during grid tied mode. The main issue related to the grid synchronization is fluctuations and outages due to lack of controllability and connectivity [5]- [9].…”

Mode Switching Smooth Control of Transient Process of Grid-Connected 400 Hz Solid-State Power Supply System

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