An impedance amplitude compensation control strategy for improvement of dynamic performance of DC microgrid

The primary purpose of this paper is to provide a comprehensive review on the time delay of impact MR buffer system. The phenomenon of time delay which occurs in most of the MR buffer systems has been given little attentions especially in the applications where little time delay is demanded. Furthermore, the methods of reducing time delay have not been discussed in detail. So, in this study, several efforts have been made to decrease or even eliminate the phenomenon of time delay. Firstly, we analyzed two kinds of power supply sources and coil winding patterns. Next, an advanced correcting circuit was designed and the parameters of transfer function were determined by experimental data. The results show that, compared with the original circuit, it only takes 5ms to achieve 95% of the final state after correction, which increases 75% immediately. Furthermore, to evaluate the effect of compensation control strategy on time delay, the adaptive Smith compensation control was adopted and tested. Using the open on-off control strategy, four operating start times of current were applied, ranging from 0 to 300ms in increments of 100ms. The results show that the original maximum time delay is more than 150ms and it can be reduced to less than 50ms by adaptive smith compensation. Further analysis illustrates that decreasing time delay improves the dynamic performance of MRD in the buffer process, such as decreased overshoot, less fluctuation etc.

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Dynamic compensation control strategy of DC bus voltage based on residual generator

Science Progress ◽

10.1177/00368504211026284 ◽

2021 ◽

Vol 104 (2) ◽

pp. 003685042110262

Author(s):

Changbin Hu ◽

Heng Lu ◽

Haipeng Wang ◽

Jinghua Zhou ◽

Shanna Luo ◽

...

Keyword(s):

Control Strategy ◽

System Structure ◽

Current Loop ◽

Voltage Fluctuations ◽

Dynamic Compensation ◽

Dc Microgrid ◽

Compensation Control ◽

Dc Bus ◽

Bus Voltage ◽

Residual Generator

Aiming at the problem of bus voltage control in DC microgrid, a dynamic compensation control strategy based on a residual generator is designed to complete the voltage compensation of DC-DC converter. Firstly, based on the DC microgrid system architecture, the bus voltage fluctuations are analyzed theoretically, and then the DC-DC converter state-space mathematical models of the DC microgrid system are established to obtain the input-output relationship of the control system. Based on the theory of double coprime decomposition and Youla parameterization stable controller, the proposed control architecture based on the residual generator is obtained, and the output value generated by the current disturbance is compensated in reverse by applying model matching theory. The voltage loop compensation controller Q( s) is obtained by the linear matrix inequality method (LMI), and the current loop compensation controller H( s) is designed according to the dynamic structure diagram of the DC-DC converter. Hardware-in-the-loop simulation (HILS) results show that the architecture can improve the dynamic performance of the DC-DC converter without changing the original system structure parameters, and suppress the DC bus voltage fluctuations caused by load switching, power fluctuations, and AC-side load imbalances, and enhance the robustness of the system.

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Torque Ripple Reduction Analysis and Dynamic Performance Improvement of PMSM Drives Based on Direct Torque Control Strategy

International Review of Electrical Engineering (IREE) ◽

10.15866/iree.v8i2.1769 ◽

2013 ◽

Vol 8 (2) ◽

pp. 711

Author(s):

Selin Ozcira ◽

Nur Bekiroglu ◽

Ibrahim Senol

Keyword(s):

Performance Improvement ◽

Control Strategy ◽

Dynamic Performance ◽

Direct Torque Control ◽

Torque Ripple ◽

Torque Control ◽

Torque Control Strategy ◽

Torque Ripple Reduction ◽

Ripple Reduction

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Bidirectional Power Sharing for DC Microgrid Enabled by Dual Active Bridge DC-DC Converter

Energies ◽

10.3390/en14020404 ◽

2021 ◽

Vol 14 (2) ◽

pp. 404

Author(s):

Sara J. Ríos ◽

Daniel J. Pagano ◽

Kevin E. Lucas

Keyword(s):

Power Management ◽

Distribution Systems ◽

Control Method ◽

Dynamic Performance ◽

Management Control ◽

Photovoltaic System ◽

Dc Microgrid ◽

Dual Active Bridge ◽

Control Scheme ◽

Bidirectional Power Flow

Currently, high-performance power conversion requirements are of increasing interest in microgrid applications. In fact, isolated bidirectional dc-dc converters are widely used in modern dc distribution systems. The dual active bridge (DAB) dc-dc converter is identified as one of the most promising converter topology for the mentioned applications, due to its benefits of high power density, electrical isolation, bidirectional power flow, zero-voltage switching, and symmetrical structure. This study presents a power management control scheme in order to ensure the power balance of a dc microgrid in stand-alone operation, where the renewable energy source (RES) and the battery energy storage (BES) unit are interfaced by DAB converters. The power management algorithm, as introduced in this work, selects the proper operation of the RES system and BES system, based on load/generation power and state-of-charge of the battery conditions. Moreover, a nonlinear robust control strategy is proposed when the DAB converters are in voltage-mode-control in order to enhance the dynamic performance and robustness of the common dc-bus voltage, in addition to overcoming the instability problems that are caused by constant power loads and the dynamic interactions of power electronic converters. The simulation platform is developed in MATLAB/Simulink, where a photovoltaic system and battery system are selected as the typical RES and BES, respectively. Assessments on the performance of the proposed control scheme are conducted. Comparisons with the other control method are also provided.

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Novel Control Strategy for Enhancing Microgrid Operation Connected to Photovoltaic Generation and Energy Storage Systems

Electronics ◽

10.3390/electronics10111261 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1261

Author(s):

Dina Emara ◽

Mohamed Ezzat ◽

Almoataz Y. Abdelaziz ◽

Karar Mahmoud ◽

Matti Lehtonen ◽

...

Keyword(s):

Energy Storage ◽

Control Strategy ◽

Voltage Stability ◽

Storage Systems ◽

Voltage Source ◽

Stable Operation ◽

Energy Storage Systems ◽

Dc Microgrid ◽

Photovoltaic Generation ◽

Dc Voltage

Recently, the penetration of energy storage systems and photovoltaics has been significantly expanded worldwide. In this regard, this paper presents the enhanced operation and control of DC microgrid systems, which are based on photovoltaic modules, battery storage systems, and DC load. DC–DC and DC–AC converters are coordinated and controlled to achieve DC voltage stability in the microgrid. To achieve such an ambitious target, the system is widely operated in two different modes: stand-alone and grid-connected modes. The novel control strategy enables maximum power generation from the photovoltaic system across different techniques for operating the microgrid. Six different cases are simulated and analyzed using the MATLAB/Simulink platform while varying irradiance levels and consequently varying photovoltaic generation. The proposed system achieves voltage and power stability at different load demands. It is illustrated that the grid-tied mode of operation regulated by voltage source converter control offers more stability than the islanded mode. In general, the proposed battery converter control introduces a stable operation and regulated DC voltage but with few voltage spikes. The merit of the integrated DC microgrid with batteries is to attain further flexibility and reliability through balancing power demand and generation. The simulation results also show the system can operate properly in normal or abnormal cases, thanks to the proposed control strategy, which can regulate the voltage stability of the DC bus in the microgrid with energy storage systems and photovoltaics.

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