scholarly journals Adaptive-MPPT-Based Control of Improved Photovoltaic Virtual Synchronous Generators

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1834 ◽  
Author(s):  
Xiangwu Yan ◽  
Jiajia Li ◽  
Ling Wang ◽  
Shuaishuai Zhao ◽  
Tie Li ◽  
...  

The lack of inertia and damping mechanism of photovoltaic (PV) grid-connected systems controlled by maximum power point tracking (MPPT) poses a challenge for the safety and stability of the grid. Virtual synchronous generator (VSG) technology has attracted wide attention, since it can make PV grid-connected inverter present the external characteristics of a synchronous generator (SG). Nevertheless, traditional PV-VSG is generally equipped with an energy storage device, which leads to many problems, such as increased costs, space occupation, and post-maintenance. Thus, this paper proposes a two-stage improved PV-VSG control method based on an adaptive-MPPT algorithm. When PV power is adequate, the adaptive-MPPT allows the PV to change the operating point within a stable operation area to actualize system supply-demand, matching in accordance to the load or dispatching power demand; when PV power is insufficient, PV achieves traditional MPPT control to reduce power shortage; simultaneously, improved VSG control prevents the DC bus voltage from falling continuously to ensure its stability. The proposed control approach enables the two-stage PV-VSG to supply power to loads or connect to the grid without adding additional energy storage devices, the effectiveness of which in off-grid and grid-connected modes is demonstrated by typical simulation conditions.

2021 ◽  
Author(s):  
Wei Huang

A control method for the stand-alone wind power generation system with induction generator and energy storage devices is proposed in this thesis. A fixed-speed self-excited induction generator is directly connected to the standalone power system, while battery powered energy storage devices are employed to balance the system power flow. A DC-AC power converter is connected between the energy storage device and the standalone power system, which maintains the voltage and frequency constant. Direct voltage control with current limits is developed for the converter with dynamic fast response. Mathematical models are developed to analysis the system performance as well as to design the lead-lag regulators in the control system. The proposed system is verified in the simulation and experiment.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4000
Author(s):  
Eunhwan Kim ◽  
Juyeon Han ◽  
Seokgyu Ryu ◽  
Youngkyu Choi ◽  
Jeeyoung Yoo

For decades, improvements in electrolytes and electrodes have driven the development of electrochemical energy storage devices. Generally, electrodes and electrolytes should not be developed separately due to the importance of the interaction at their interface. The energy storage ability and safety of energy storage devices are in fact determined by the arrangement of ions and electrons between the electrode and the electrolyte. In this paper, the physicochemical and electrochemical properties of lithium-ion batteries and supercapacitors using ionic liquids (ILs) as an electrolyte are reviewed. Additionally, the energy storage device ILs developed over the last decade are introduced.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Hu ◽  
Xiaomin Tang ◽  
Qing Dai ◽  
Zhiqiang Liu ◽  
Huamin Zhang ◽  
...  

AbstractMembranes with fast and selective ions transport are highly demanded for energy storage devices. Layered double hydroxides (LDHs), bearing uniform interlayer galleries and abundant hydroxyl groups covalently bonded within two-dimensional (2D) host layers, make them superb candidates for high-performance membranes. However, related research on LDHs for ions separation is quite rare, especially the deep-going study on ions transport behavior in LDHs. Here, we report a LDHs-based composite membrane with fast and selective ions transport for flow battery application. The hydroxide ions transport through LDHs via vehicular (standard diffusion) & Grotthuss (proton hopping) mechanisms is uncovered. The LDHs-based membrane enables an alkaline zinc-based flow battery to operate at 200 mA cm−2, along with an energy efficiency of 82.36% for 400 cycles. This study offers an in-depth understanding of ions transport in LDHs and further inspires their applications in other energy-related devices.


Clean Energy ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 196-207
Author(s):  
Shoichi Sato ◽  
Yasuhiro Noro

Abstract The introduction of large-scale renewable energy requires a control system that can operate multiple distributed inverters in a stable way. This study proposes an inverter control method that uses information corresponding to the inertia of the synchronous generator to coordinate the operation of battery energy storage systems. Simulation results for a system with multiple inverters applying the control method are presented. Various faults such as line-to-line short circuits and three-phase line-to-ground faults were simulated. Two fault points with different characteristics were compared. The voltage, frequency and active power quickly returned to their steady-state values after the fault was eliminated. From the obtained simulation results, it was verified that our control method can be operated stably against various faults.


2018 ◽  
Vol 180 ◽  
pp. 02011 ◽  
Author(s):  
Petru Valentin Radu ◽  
Adam Szeląg

The paper presents a Simulink model of a DC metro traction supply system with a stationary energy storage device (SESD). The simulation model consists of traction substations, a train model, and an energy storage device (ESD) with supercapacitors (SC). A new energy management strategy considering the line voltage and current, SC state of charge (SOC) and SC charging and discharging current is proposed. This method can improve the energy savings and manage the remaining energy. Simulation results provided in this paper justify the control method. The proposed model can be used with different ESD, such as batteries.


2020 ◽  
Author(s):  
Jing Hu ◽  
Xiaomin Tang ◽  
Qing Dai ◽  
Zhiqiang Liu ◽  
Huamin Zhang ◽  
...  

Abstract Membranes with fast and selective ions transport are highly demanded for energy storage devices. Layered double hydroxides (LDHs), bearing uniform interlayer galleries and abundant hydroxyl groups covalently bonded within two-dimensional (2D) host layers, make them superb candidates for high-performance membranes. However, related research on LDHs for ions separation is quite rare, especially the deep-going study on ions transport behavior in LDHs. Here, we report a LDHs-based composite membrane with fast and selective ions transport for flow battery application. The hydroxide ions transport through LDHs via vehicular (standard diffusion) & Grotthuss (proton hopping) mechanisms is uncovered. The LDHs-based membrane enables an alkaline zinc-based flow battery to operate at 200 mA cm− 2, along with an energy efficiency of 82.36% for 400 cycles, which is among the highest efficiencies for zinc-based flow batteries. This study offers an in-depth understanding of ions transport in LDHs and further inspires their applications in other energy-related devices.


2021 ◽  
Author(s):  
Muhammad Irfan ◽  
Xianhua Liu ◽  
Suraya Mushtaq ◽  
Jonnathan Cabrera ◽  
Pingping Zhang

Abstract Development of sustainable electrochemical energy storage devices faces great challenge in exploring highly efficient and low cost electrode materials. Biomass waste derived carbonaceous materials can be used as an alternative to expensive metals in supercapacitor. However, their application limited by low performance. In this study, the combination use of persimmon waste derived carbon and transition metal nitride demonstrated strong potential for supercapacitor application. Persimmon based carbonaceous gel decorated with bimetallic-nitride (N-NiCo/PC) was firstly synthesized through a green hydrothermal method. Electrochemical properties of N-NiCo/PC as electrode in 6 M KOH electrolyte solution were evaluated by using cyclic voltammetry (CV) and charge-discharge measurements. The N-NiCo/PC exhibited 895.5 F/g specific capacitance at 1 A/g current density and maintained 91.5% capacitance retention after 900 cycles. Hence, the bimetallic nitride-based-composite catalyst is a potentially suitable material for high-performance energy storage devices. In addition, this work demonstrated a promising pathway for transforming environmental waste into sustainable energy conversion materials.


2022 ◽  
Vol 9 ◽  
Author(s):  
Adriana M. Navarro-Suárez ◽  
Milo S. P. Shaffer

Structural energy storage devices (SESDs), designed to simultaneously store electrical energy and withstand mechanical loads, offer great potential to reduce the overall system weight in applications such as automotive, aircraft, spacecraft, marine and sports equipment. The greatest improvements will come from systems that implement true multifunctional materials as fully as possible. The realization of electrochemical SESDs therefore requires the identification and development of suitable multifunctional structural electrodes, separators, and electrolytes. Different strategies are available depending on the class of electrochemical energy storage device and the specific chemistries selected. Here, we review existing attempts to build SESDs around carbon fiber (CF) composite electrodes, including the use of both organic and inorganic compounds to increase electrochemical performance. We consider some of the key challenges and discuss the implications for the selection of device chemistries.


2021 ◽  
Vol 1 (3) ◽  
pp. 49-56
Author(s):  
S.M. Zuyev ◽  
◽  
R.A. Maleyev ◽  
YU.M. Shmatkov ◽  
M.YU. Khandzhalov ◽  
...  

This article provides a comparative analysis of various energy storage devices. A detailed review and analysis of molecular energy storage units is carried out, their main characteristics and parame-ters, as well as their application areas, are determined. The main types of molecular energy storage are determined: electric double layer capacitors, pseudo capacitors, hybrid capacitors. Comparison of the characteristics of various batteries is given. The parameters of various energy storage devices are presented. The analysis of molecular energy storage devices and accumulators is carried out. Ttheir advantages and disadvantages are revealed. It has been shown that molecular energy storage or double layer electrochemical capacitors are ideal energy storage systems due to their high specific energy, fast charging and long life compared to conventional capacitors. The article presents oscillograms of a lithium-ion battery with a voltage of 10.8 V at a pulsed load current of 2A of a laptop with and without a molecular energy storage device, as well as oscil-lograms of a laptop with DVD lithium-ion battery with a voltage of 10.8 V with a parallel shutdown of a molecular energy storage device with a capacity of 7 F and without it. The comparative analysis shows that when the molecular energy storage unit with a 7 F capacity is switched on and off, transient processes are significantly improved and there are no supply voltage dips. The dependenc-es of the operating time of a 3.6 V 600 mAh lithium-ion battery at a load of 2 A for powering mo-bile cellular devices with and without a molecular energy storage are given. It is shown that when the molecular energy storage device is switched on, the battery operation time increases by almost 20%.


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