Energy Storage Control Strategy Research Articles

Review of Energy Storage and Energy Management System Control Strategies in Microgrids

A microgrid (MG) is a discrete energy system consisting of an interconnection of distributed energy sources and loads capable of operating in parallel with or independently from the main power grid. The microgrid concept integrated with renewable energy generation and energy storage systems has gained significant interest recently, triggered by increasing demand for clean, efficient, secure, reliable and sustainable heat and electricity. However, the concept of efficient integration of energy storage systems faces many challenges (e.g., charging, discharging, safety, size, cost, reliability and overall management). Additionally, proper implementation and justification of these technologies in MGs cannot be done without energy management systems, which control various aspects of power management and operation of energy storage systems in microgrids. This review discusses different energy storage technologies that can have high penetration and integration in microgrids. Moreover, their working operations and characteristics are discussed. An overview of the controls of energy management systems for microgrids with distributed energy storage systems is also included in the scope of this review.

Fully decentralized control strategy for heterogeneous energy storage systems distributed in islanded DC datacentre microgrid

Currently, communication-based distributed cooperative control strategies are employed to control energy storage systems in an islanded DC datacentre microgrid. This paper proposes a fully decentralized, communication-less control strategy for heterogeneous energy storage devices distributed in the DC datacentre. In the proposed strategy, decentralized virtual resistance based control allocates the low frequency component of loads to batteries while the high frequency component is allocated to ultracapacitors with the virtual capacitive droop control. Furthermore, the proposed control system balances the batteries’ state of charges to a common value. During operation, the microgrid local bus voltages are regulated within 360–400 V range in accordance with the ETSI EN 300 132-3-1 standard. The proposed control approach offers advantages in terms of reliability and flexibility, as it does not require any communication infrastructure. Performance of the proposed decentralized control strategy is demonstrated on an islanded 380 VDC datacentre microgrid with variable loads, using Real-Time Digital Simulator (RTDS) with detailed switching converter models and nonlinear battery models.

Cascade Utilization Battery Energy Storage System Architecture and Control Strategy

Cascade Utilization Battery Energy Storage System Architecture and Control Strategy

Research on Coordinated Control Strategy of Energy Storage Participating in Primary Frequency Regulation Considering Frequency Deviation Change Rate

In order to further improve the performance of primary frequency modulation (PFM) by battery energy storage, a new control strategy is proposed. By analysing the characteristics of virtual inertia response and virtual droop control, the artificial dead zone of energy storage participating in frequency modulation is set based on virtual inertial control to make it respond quickly and improve the characteristics of energy storage to suppress frequency deviation change rate; In this paper, the remaining energy and load disturbance of the energy storage battery are taken as the double inputs, and the fuzzy control strategy is used to derive the function relationship between the virtual droop coefficient and the two inputs to ensure that the charging and discharging power of the energy storage battery is suitable for the actual needs. The load change rate is used to predict the load change at the next moment. Based on this, the coefficients of virtual inertia control and virtual droop control are determined, and the output coefficients of both are optimized to achieve the optimal frequency regulation effect. Three evaluation indexes are proposed to evaluate the control strategy in this paper. Finally, the simulation model is established in MATLAB/Simulink and the case study is carried out in a regional power grid. The proposed strategy can effectively improve the primary frequency regulation of power grid and has positive significance for maintaining energy storage battery.

Research on the Structure and Control Strategy of Energy Storage Grid Connected Inverter

This paper studied the structure of energy storage grid connected inverter which is composed of super capacitor, bi-directional DC/DC converter, and voltage type DC/AC converter. The working principle of bi-directional DC/DC converter and DC/AC converter was separately analyzed. Then a joint control strategy of DC/DC converter and DC/AC converter was proposed with the main control objective of maintaining DC bus voltage. According to the different states of DC bus voltage and super capacitor voltage, five control modes of energy storage inverter were set. Besides, the DC/AC converter was controlled to compensate the reactive power and harmonics, and provide certain active power for the power grid according to the actual situation. Finally, the effectiveness of the proposed energy storage inverter structure and control strategy were verified through simulation analysis.

Optimal configuration and economic operation of energy storage system considering photovoltaic consumption rate

The outstanding photovoltaic (PV) abandonment problem can be effectively solved by configuring energy storage (ES). The capacity configuration and operation control strategy of ES are the main difficulty in the economic operation of the system. In this paper, a comprehensive evaluation model is established to evaluate the economics of ES to improve PV consumption. Further, an ES capacity configuration method based on double-layer optimization is proposed. The upper optimization uses PV curtailment rate to determine the feasible region of ES capacity configuration. The comprehensive economic benefits are used as the inner optimization indicator to optimize the capacity configuration of ES. The ES charging and discharging strategy used in the paper can realize the efficient use of PV power. The simulation result proves the effectiveness of the proposed method.

Research on energy storage participating in frequency modulation based on fuzzy partition coordinated control

Energy storage has the advantages of fast response and accurate power tracking when participates in frequency modulation. By dividing the Area Control Error (ACE) and battery’s State of Charge (SOC) into different regions, combining them with four different emergency frequency modulation states, this paper proposes a partition coordinated control strategy for energy storage to participate in frequency modulation. According to the regional interconnected system, the model of energy storage participating in power grid frequency modulation is built in MATLAB/Simulink. Based on the conventional control and the partition coordinated control, the frequency waveform analyzed. The results show that the energy storage participating in frequency modulation can effectively shorten the regulation time and reduce the frequency fluctuation. The fuzzy control used to optimize the partition coordinated control strategy to make the whole link have better frequency modulation ability.

Rule-Based Control Strategy to Increase Photovoltaic Self-Consumption of a Modulating Heat Pump Using Water Storages and Building Mass Activation

The use of photovoltaic (PV) energy in combination with heat pump systems for heating and cooling of residential buildings can lead to renewable energy self-consumption, reducing the energy required from the grid and the carbon footprint of the building uses. However, energy storage technologies and control strategies are essential to enhance the self-consumption level. This paper proposes and analyzes a new control strategy for the operation of a modulating air-source heat pump, based on the actual PV availability. The solar energy surplus is stored as thermal energy by the use of water tanks and the activation of the thermal capacitance of the building. The efficacy of the control strategy is evaluated considering different rule-based strategies, and different boundary conditions. The effect of climate data, building insulation level and thermal inertia are investigated and compared. The results show the efficacy of the proposed strategy to decrease up to 17% the amount of electricity purchased from the grid and to increase the self-consumption by 22%, considering a high-insulated building in Bolzano, Northern Italy. The thermal mass activation is found effective to increase the self-consumption of the system. Nonetheless, the achievable energy reduction depends largely on the building characteristics and the boundary conditions.

Output Voltage Control of MMC-Based Microgrid Based on Voltage Fluctuation Compensation Sliding Mode Control

As a novel topology of microgrid, the output voltage control of MMC half bridge series microgrid (MMC-MG) is rarely studied. In this paper, on the basis of fully analyzing the mechanism of output voltage fluctuation of MMC-MG under the condition of islanded mode, a control strategy of a hybrid energy storage system is proposed to reduce the generating module (GM) DC-link voltage fluctuation caused by the randomness of renewable energy microsource output power. Moreover, in order to further improve the stabilization of the MMC-MG output voltage and meet the requirements of fast voltage recovery and antijamming, a sliding mode controller is designed. Then, a voltage fluctuation compensation controller is designed to suppress the DC component and fundamental frequency deviation of system output voltage caused by GM DC-link voltage fluctuation. The proposed control approach is validated against simulations using MMC-MG models with 4-GM per arm. The results show that the proposed hybrid energy storage control strategy can suppress the GM DC-link voltage fluctuation, the sliding mode controller can stabilize the system output voltage when the load drastic changes, and the fluctuation compensation strategy can suppress the DC component and the fundamental frequency deviation of system output voltage.

Energy storage traction power supply system and control strategy for an electrified railway

To solve the negative sequence (NS) problem and enhance the regenerative braking energy (RBE) utilisation in an electrified railway, a novel energy storage traction power supply system (ESTPSS) is proposed in this study. In the new system, a power flow controller is adopted to compensate for the NS, and a super-capacitor energy storage system is applied to absorb and release the RBE. In addition, through the cooperation of each part, the proposed power supply system can provide continuous power without neutral sections. The NS compensation principle of the new system is illustrated. Depending on the operational state of the traction load, the control model is presented for different working patterns, including a regenerative braking pattern, a peak clipping pattern and a valley filling pattern. Moreover, a hierarchical control strategy including upper energy management and low-layer converter control is proposed, which effectively coordinate switches between the different working patterns. Finally, the validity of the control method and the excellent performance of the system are demonstrated by a case study. The results indicate that compared to a conventional TPSS, the ESTPSS increases the RBE utilisation of the system by 83%.

Control Strategy of Hybrid Energy Storage System for a Standalone Photovoltaic System

Energy storage technologies are used with photovoltaic systems to overcome prob-lems due to varying operating conditions. This paper presents an advance control strategy for battery-supercapacitor hybrid energy storage that can be effective in dealing with the slow response of the battery. Modeling and simulation of a standalone photovoltaic system are done on MATLAB/ SIMULINK to analyze the behavior of the advance control strategy. The traditional control approach uses a low pass filter to supply slow transient power demand to the battery and fast transient power demand to the supercapacitor. But due to steady response of the battery, the power supplied by the battery does not follow the load power accurately. This con-trol approach is modified to supply the uncompensated power through the supercapacitor till the battery reaches steady state. The proposed control strategy helps in fast recovery of DC voltage during sudden power fluctuations and also enhances the battery life-span.

Distributed energy storage node controller and control strategy based on energy storage cloud platform architecture

Based on the energy storage cloud platform architecture, this study considers the extensive configuration of energy storage devices and the future large-scale application of electric vehicles at the customer side to build a new mode of smart power consumption with a flexible interaction, smooth the peak/valley difference of the load side power, and improve energy efficiency. A plug and play device for customer-side energy storage and an internet-based energy storage cloud platform are developed herein to build a new intelligent power consumption mode with a flexible interaction suitable for ordinary customers. Based on the load perception of the power grid, this study aims to investigate the operating state and service life of distributed energy storage devices. By selecting an integrated optimal control scheme, this study designs a kind of energy optimization and deployment strategy for stratified partition to reduce the operating cost of the energy storage device on the client side. The effectiveness of the system and the control strategy is verified through the Suzhou client-side distributed energy storage demonstration project.

Simulation and contrast study on flywheel energy storage control strategy for dynamic stabilization of power fluctuation in power grid

Flywheel Energy Storage System can not only effectively reduce the impact of energy fluctuation on the power grid, but also fully improve the utilization of distributed energy system because of its characteristics of energy storage and rapid charging. In this study, permanent magnet brushless DC motor is selected as flywheel motor for wind power system. The mathematical model of flywheel energy storage system in rectangular coordinate system is established. The double closed-loop simulation model of speed and current of flywheel energy storage system is built by using MATLAB/Simulink. In order to improve the control performance of flywheel energy storage system, three different control strategies, PID control, sliding mode variable structure control and ADRC control, were used to simulate the charging and discharging dynamic process of FESS. Considering the particularity of flywheel energy storage system as a limited energy storage unit, the controller parameters of three traditional control modes are adjusted effectively on the premise of keeping the parameters of the flywheel motor unchanged. The simulation results are compared from rotation rate and torque, and the advantages and disadvantages of three control strategies and the dynamic performance of flywheel energy storage system under different control strategies are analyzed.

Improved Droop Control Strategy of Energy Storage in Islanded Microgrid

In islanded AC microgrid, droop control strategy is usually adopted for independent distributed generators (DG) which can realize coordinated operation of each unit under the conditions of less data communication. For different capacity of energy storages (ES) system, due to the difference of SOC value, capacity and other state parameters, some units may reach the threshold quickly, thus affecting the system stability. Therefore, on the basis of traditional droop control, combined with the SOC value of energy storage unit, the droop curve which is automatically adjusted with the change of SOC value is constructed. At the same time, the bus voltage is corrected to run at a predetermined point through the voltage feedback link to eliminate the voltage fluctuation. Finally, a microgrid model with dual energy storage system is built inMatlab/Simulink simulation environment. Theresults show that the improved droop control method can make the SOC values of the two energy storages consistent.

Quantification of energy flexibility of residential net-zero-energy buildings involved with dynamic operations of hybrid energy storages and diversified energy conversion strategies

Abstract For immediate response and sufficient reaction to building energy demands by avoiding excessive production, increasing stability of energy networks, and minimising energy congestion, building energy flexibility has potentials to enhance the resilience of hybrid grids to fluctuations in energy demands of multi-energy systems. However, few studies focused on dealing with the complexity of energy flexibility quantification regarding diversified energy conversions and hybrid energy storages. Moreover, few studies focused on the exploitation of energy potential provided by building energy systems itself through flexible energy control strategy. In this study, a generic methodology was proposed to characterise energy flexibility of diversified energy systems. A series of new flexibility indicators are proposed such as flexible power, flexible electricity, on-site flexible electric load fraction, on-site flexible surplus renewable fraction ratio, and flexibility factors. Technical solutions are proposed to improve the energy flexibility using integrated solutions of energy conversion, energy storage, and rule-based control strategies. Case studies with different control strategies (i.e. “battery-to-demand control strategy” and “renewable-to-demand control strategy”) are studied for the technical viability assessment. This study provides a generic methodology to characterise the energy flexibility regarding sophisticated building energy systems, and a rule-based control strategy for the flexibility enhancement, which will be effective in the promotion of energy flexible buildings.

Study on Hybrid Energy Storage Configuration and Control Strategy of Grid-connected Wind Hydrogen System

The randomness and volatility of wind energy bring great challenges to wind power grid-connected. The hybrid energy storage technology based on electrolysis cell hydrogen production and super capacitor has become an effective way to stabilize wind power fluctuations. Based on the establishment of the grid-type wind-hydrogen coupling system working characteristic constraint and the minimum initial investment cost of the hybrid energy storage system, an alkaline electrolytic cell-super capacitor hybrid storage based on low-pass filtering-fluctuation observation is proposed. The method can be configured, and a hybrid energy storage coordinated control strategy based on the super capacitor SOC (state of charge) is developed. The case study results show that the hybrid energy storage system configuration method and control strategy proposed in this paper are effective, which can reduce the fluctuation of wind power grid-connected power to meet the grid connection standard.

Model Predictive Control Method of hybrid Battery energy storage system for Smoothing Wind Power Fluctuation

In a large-scale wind power generation system, active power fluctuation caused by random wind speed will have a serious impact on the power grid. In order to limit the power fluctuation that wind farm transmits to the power grid and protect the energy storage battery, this paper has proposed a model predictive control method of hybrid energy storage by optimizing the objective function and constraint conditions. Firstly, the mathematical model of predictive control method has been established in a wind power system with hybrid energy storage. Then, with the goal of minimum energy storage output and maximum charging-discharging capacity of the super-capacitor, the predictive control process has been optimized. Meanwhile, the constraint on the output power of the battery has been dynamically changed to reduce its charging-discharging switching frequency, and the model predictive control strategy of the hybrid energy storage has been formed. Finally, compared with the model prediction control method of single energy storage, based on a wind farm data, the simulation results show that the proposed method can smooth wind power fluctuation, reduce the time that the power does not satisfy the fluctuation requirements, ensure the capability of the super-capacitor, and reduce the charging-discharging switching frequency of the energy storage battery.

Retracted: Distributed buildings energy storage charging load forecasting method considering parallel deep learning model

SummaryAt present, with total building energy consumption accounts for about 21.33% of the energy consumption of social terminals, the building energy consumption has a tendency to continue to grow. According to the geographical location of users and the local weather conditions, we analyze the energy resources available to users and design a multienergy complementary coupling system. We have taken full account of the use of renewable energy and recovery of waste heat resources. Large‐scale increase of electrical equipment, a large number of charging load access to the grid, the power system planning, operation and operation of the electricity market will have a profound impact. The current mode of the supercapacitor and the DC bus determines the mode of operation of the converter. Based on a detailed analysis of each working mode, we design a corresponding control scheme and achieve a smooth transition and switching between modes. Simulation and experiment verify the correctness and effectiveness of the converter and hybrid energy storage control strategy.

A control strategy for hybrid energy storage based on double-layer fuzzy controller integrated with second-ahead control thought

With the continuous increase in the penetration of renewable energy resources, such as wind power, into power grids, fluctuations in power output introduce significant challenges to the power grid's safe and reliable operation. The hybridization of energy storage technologies effectively stabilizes fluctuations from wind power. This paper proposes a hybrid energy storage control strategy based on an adaptive wavelet decomposition and fuzzy control theory. Firstly, to meet the fluctuation requirements for the power output from wind farms, a wavelet packet decomposition approach is used to determine the grid-connected wind power and power allocation for different energy storage techniques by considering the power output characteristics and lifecycles. Secondly, the use of prediction results from the energy storage power output combined with a two-layer fuzzy controller enables advanced control of the energy storage system and optimal operation of the power output for different types of energy storage systems. The results show that the proposed strategy can effectively be applied to suppress the second-level wind power fluctuations and allocate the output of the hybrid energy storage system. Furthermore, this approach eliminates possible limit violation phenomena while operating the energy storage device to achieve optimal coordination for different energy storage systems considering the lifecycles of the energy storage device.

A Capacity Configuration Control Strategy to Alleviate Power Fluctuation of Hybrid Energy Storage System Based on Improved Particle Swarm Optimization

In view of optimizing the configuration of each unit’s capacity for energy storage in the microgrid system, in order to ensure that the planned energy storage capacity can meet the reasonable operation of the microgrid’s control strategy, the power fluctuations during the grid-connected operation of the microgrid are considered in the planning and The economic benefit of hybrid energy storage is quantified. A multi-objective function aiming at minimizing the power fluctuation on the DC bus in the microgrid and optimizing the capacity ratio of each energy storage system in the hybrid energy storage system (HESS) is established. The improved particle swarm algorithm (PSO) is used to solve the objective function, and the solution is applied to the microgrid experimental platform. By comparing the power fluctuations of the battery and the supercapacitor in the HESS, the power distribution is directly reflected. Comparing with the traditional mixed energy storage control strategy, it shows that the optimized hybrid energy storage control strategy can save 4.3% of the cost compared with the traditional hybrid energy storage control strategy, and the performance of the power fluctuation of the renewable energy is also improved. It proves that the proposed capacity configuration of the HESS has certain theoretical significance and practical application value.