Cost-Function-Based Microgrid Decentralized Control of Unbalance and Harmonics for Simultaneous Bus Voltage Compensation and Current Sharing

2019 ◽  
Vol 34 (8) ◽  
pp. 7397-7410 ◽  
Author(s):  
Jia Liu ◽  
Yushi Miura ◽  
Toshifumi Ise
2015 ◽  
Vol 2 (1) ◽  
pp. 61 ◽  
Author(s):  
S. J. Chiang ◽  
Yu-Min Liao ◽  
Ke-Chih Liu

The micro grid system requires battery for energy storage and power management. In which, the bi-directional DC to DC converter is the key component for maintaining the DC bus voltage and controlling the charge and discharge of the battery with or without grid support. Parallel control of multiple DC to DC converters is a critical technique to enlarge the power capacity. This paper presents two capacity limitation control methods that multiple DC to DC converters can be paralleled with distributed battery banks. The first method is the capacity limitation control with cascaded load current sense needing no control interconnection. The second method is the capacity limitation control with master-slave and cascaded current command limitation. Two methods are presented to solve the limitation of droop control method and active current sharing method respectively, and can be extended without converter number limitation theoretically. Three prototype 240W bidirectional half-bridge DC to DC converters are built and paralleled in this paper. The proposed method is confirmed with some measured results.


2019 ◽  
Vol 2019 (16) ◽  
pp. 3056-3061 ◽  
Author(s):  
Sucheng Liu ◽  
Zhongpeng Li ◽  
Wenjie Liu ◽  
Xiaodong Liu

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2995 ◽  
Author(s):  
Liang Zhang ◽  
Kang Chen ◽  
Shengbin Chi ◽  
Ling Lyu ◽  
Guowei Cai

In the direct current (DC) microgrid composed of multiple distributed generations, due to the different distances between various converters and the DC bus in the system, the difference of the line resistance will reduce the current sharing accuracy of the system. The droop control was widely used in the operation control of the DC microgrid. It was necessary to select a large droop coefficient to improve the current sharing accuracy, but a too large droop coefficient will lead to a serious bus voltage drop and affect the power quality. In view of the contradiction between the voltage regulation and load current sharing in the traditional droop control, a hierarchical control algorithm based on the improved droop control of the fuzzy logic was proposed in this paper. By improving the droop curve, the problems of voltage regulation and current sharing were solved simultaneously. The effectiveness of the algorithm was verified by simulation.


Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1114
Author(s):  
Sung-Hun Kim ◽  
Bum-Jun Kim ◽  
Jung-Min Park ◽  
Chung-Yuen Won

Input-Series-Output-Parallel (ISOP) converters, a kind of modular converter, are used in high-input voltage and high-output current applications. In ISOP converters, Input Voltage Sharing (IVS) and Output Current Sharing (OCS) should be implemented for stable operation. In order to solve this problem, this paper proposes a decentralized control method. In the proposed control, output current reference is changed according to the decentralized control characteristic in individual current control loops. In this way, the proposed control method is able to implement IVS and OCS without communication. Also, this method can be easily used in current control loops and has high reliability compared to conventional control methods that require communication. In this paper, the operation principle is described to elucidate the proposed control and a small signal model of an ISOP converter is also implemented. Based on the small signal model, IVS stability analysis is performed using pole-zero maps with varying coefficients and control gains. In addition, the current control loop is designed in a stable region. In order to demonstrate the proposed control method, a prototype ISOP converter is configured using full-bridge converters. The performance of IVS and OCS in an ISOP converter is verified by experimental result.


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