Power Generation Technology ›› 2020, Vol. 41 ›› Issue (2): 160-166.DOI: 10.12096/j.2096-4528.pgt.19128

• Energy Internet • Previous Articles     Next Articles

Research on Three-phase Unbalance of Micro-grid Based on Active Disturbance Rejection Control

Mengran QIAN(),Hui LI*(),Xinxiu LIU   

  • Received:2019-08-26 Published:2020-04-30 Online:2020-04-23
  • Contact: Hui LI
  • Supported by:
    Shanghai International Science & Technology Cooperation Program(15220710500);Shanghai Science and Technology Commission Local College Capacity Building Program(15160500800);Shanghai Science and Technology Commission Key Program(18DZ1203200)

Abstract:

Under the condition of three-phase unbalanced load in micro-grid, three-phase four-leg inverter can solve the unbalanced three-phase output voltage because of unbalanced load. Nevertheless, in the dq0 synchronous reference frame, the output voltage and current of three-phase four-leg inverter are coupled with each other. If the load is unbalanced and the open-loop control is directly used in the dq0 synchronous reference frame, the output voltage is still unbalanced because of double frequency disturbance caused by unbalanced load. To solve these problems, this paper established the mathematical model of three-phase four-leg inverter, derived the open-loop transfer function of the controlled plant and deeply analyzed the mechanism of unbalanced output voltage of three-phase four-leg inverters. In addition, according to the system model information, a second-order active disturbance rejection controller (ADRC) controller was designed to decouple the voltage and current in dq axis, and it could reduce the number of originals measured. Proportional resonant controller was introduced to eliminate the disturbance caused by 100 Hz. Finally, the effectiveness of the solution was verified by Matlab/Simulink.

Key words: micro-grid, three-phase four-leg inverter, unbalanced voltage, dq axis decoupling, active disturbance rejection controller (ADRC), proportional resonant controller

CLC Number: