scholarly journals Control Algorithm for Equal Current Sharing between Parallel-Connected Boost Converters in a DC Microgrid

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Muamer M. Shebani ◽  
M. Tariq Iqbal ◽  
John E. Quaicoe
Keyword(s):  
Control Algorithm ◽  
High Efficiency ◽  
Control Method ◽  
Storage System ◽  
Dc Microgrid ◽  
Load Current ◽  
Total Load ◽  
Boost Converters ◽  
Current Sharing ◽  
Complexity Cost

DC microgrids are gaining more attention compared to AC microgrids due to their high efficiency and uncomplicated interconnection of renewable sources. In standalone DC microgrid, parallel-connected converters connect the storage system to the load. To achieve equal current sharing among parallel converters, several methods have been presented, but they vary in their current sharing performance, complexity, cost, and reliability. In DC microgrid, the conventional droop control method is preferred because it is more competitive in terms of cost, suitability, and reliability compared to the master-slave control method. However, the conventional droop method cannot ensure equal current sharing due to the mismatches in parameters of parallel-connected converters. To address this limitation, a control algorithm that supervises a modified droop method to achieve precise current sharing between parallel modules is proposed in this paper. The control algorithm is based on the percentage of current sharing for each module to the total load current. The output current measurement of each converter is compared to the total load current and is used to modify the nominal voltage for each converter. The effectiveness of the proposed algorithm is verified by MATLAB simulation model and experimental results.

scholarly journals The Hierarchical Control Algorithm for DC Microgrid Based on the Improved Droop Control of Fuzzy Logic

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2995 ◽  
Author(s):  
Liang Zhang ◽  
Kang Chen ◽  
Shengbin Chi ◽  
Ling Lyu ◽  
Guowei Cai
Keyword(s):  
Fuzzy Logic ◽  
Control Algorithm ◽  
Voltage Drop ◽  
Hierarchical Control ◽  
Voltage Regulation ◽  
Droop Control ◽  
Dc Microgrid ◽  
Current Sharing ◽  
The Difference ◽  
Bus Voltage

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.

scholarly journals Modified Droop Method Based on Master Current Control for Parallel-Connected DC-DC Boost Converters

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Muamer M. Shebani ◽  
Tariq Iqbal ◽  
John E. Quaicoe
Keyword(s):  
System Reliability ◽  
Current Control ◽  
Feedback Signal ◽  
Current Feedback ◽  
Load Current ◽  
Boost Converters ◽  
Control Loops ◽  
Simulink Simulation ◽  
Current Sharing ◽  
Load Regulation

Load current sharing between parallel-connected DC-DC boost converters is very important for system reliability. This paper proposes a modified droop method based on master current control for parallel-connected DC-DC boost converters. The modified droop method uses an algorithm for parallel-connected DC-DC boost converters to adaptively adjust the reference voltage for each converter according to the load regulation characteristics of the droop method. Unlike the conventional droop method, the current feedback signal (master current) for one of the parallel-connected converters is used in the inner loop controller for all converters to avoid any differences in the time delay of the control loops for the parallel-connected converters. The algorithm ensures that the load current sharing is identical to the load regulation characteristics of the droop method. The proposed algorithm is tested with a mismatch in the parameters of the parallel converters. The effectiveness of the proposed algorithm is verified using Matlab/Simulink simulation.

scholarly journals Synchronous Control Strategy with Input Voltage Feedforward for a Four-Switch Buck-Boost Converter Used in a Variable-Speed PMSG Energy Storage System

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2375
Author(s):  
Liuchen Tai ◽  
Mingyao Lin ◽  
Jianhua Wang ◽  
Chongsheng Hou
Keyword(s):  
Control System ◽  
Energy Storage ◽  
High Efficiency ◽  
Storage System ◽  
Synchronous Generator ◽  
Input Voltage ◽  
Energy Storage System ◽  
Variable Speed ◽  
Load Current ◽  
Voltage Range

The four-switch Buck-Boost (FSBB) converter can produce voltage conversion within a wide input voltage range, which is suitable for variable-speed permanent magnet synchronous generator (PMSG) energy storage systems with AC inputs and DC outputs. To reduce the interference of input voltage fluctuation on the performance of the FSBB converter, an input voltage feedforward (IVFF) compensation method is proposed in this paper. The switching synchronization strategy is simple. Using the switching average model, the small signal model of a non-ideal FSBB converter in all working modes is established. The effects of input voltage, load current, damping coefficient and right half plane (RHP) zero on the stability of the control system are analyzed in detail. The transfer function of the IVFF of the FSBB converter is derived, and the relationship between input voltage, load current and duty cycle is analyzed. Finally, the design of the parameters of the converter control system is presented. The simulation and experimental results show that this FSBB converter has high efficiency and a good transient response.

scholarly journals Extra-High-Voltage DC-DC Boost Converters Topology with Simple Control Strategy

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
P. Sanjeevikumar ◽  
K. Rajambal
Keyword(s):  
High Voltage ◽  
Output Voltage ◽  
Control Algorithm ◽  
High Efficiency ◽  
Low Cost ◽  
Buck Converter ◽  
Boost Converters ◽  
Wide Range ◽  
Power Transfer Efficiency ◽  
Extra High Voltage

This paper presents the topology of operating DC-DC buck converter in boost mode for extra-high-voltage applications. Traditional DC-DC boost converters are used in high-voltage applications, but they are not economical due to the limited output voltage, efficiency and they require two sensors with complex control algorithm. Moreover, due to the effect of parasitic elements the output voltage and power transfer efficiency of DC-DC converters are limited. These limitations are overcome by using the voltage lift technique, opens a good way to improve the performance characteristics of DC-DC converter. The technique is applied to DC-DC converter and a simplified control algorithm in this paper. The performance of the controller is studied for both line and load disturbances. These converters perform positive DC-DC voltage increasing conversion with high power density, high efficiency, low cost in simple structure, small ripples, and wide range of control. Simulation results along theoretical analysis are provided to verify its performance.

Sign in / Sign up

Export Citation Format

Share Document