IMPROVED DROOP CONTROL FOR PARALLEL （改进的下垂控制并行）.pdf

i IMPROVED DROOP CONTROL FOR PARALLEL INVERTER SYSTEM WITH LOAD SAGER K ALSWED A thesis report submitted in partial fulfillment of the requirement for the award of the Degree of Master of Electrical and Electronic Engineering Faculty of Electrical and Electronic Engineering Universiti Tun Hussien Onn Malaysia January, 2014 v ABSTRACT DC-AC converters are electronic devices used to change DC direct current to alternating current. Three-phase inverter is widely used in power electronics system applications consequently, the DC-AC converters requires a controller with a high degree. Therefore the structure of two parallel three phase inverter with load system has presented. In order to achieve load sharing between parallel inverters, the linear transformed droop control is applied. This control strategy combines frequency and voltage droop method and inverter voltage regulation control scheme. In the external power control structure, the references frequency and magnitude of inverter output voltage are obtained according to the droop characteristics. The improvement of the droop control is made to obtain a more stable voltage and better load sharing between two parallel inverters. The performance of the control strategy is verified in simulation using Matlab/Simulink. vi