The rapid development of new energy power generation technology and the transformation of power electronics in the core equipment of source-grid-load drives the power system towards the“double-high”development patte...The rapid development of new energy power generation technology and the transformation of power electronics in the core equipment of source-grid-load drives the power system towards the“double-high”development pattern of“high proportion of renewable energy”and“high proportion of power electronic equipment”.To enhance the transient performance of AC/DC hybrid microgrid(HMG)in the context of“double-high,”aπtype virtual synchronous generator(π-VSG)control strategy is applied to bidirectional interface converter(BIC)to address the issues of lacking inertia and poor disturbance immunity caused by the high penetration rate of power electronic equipment and new energy.Firstly,the virtual synchronous generator mechanical motion equations and virtual capacitance equations are used to introduce the virtual inertia control equations that consider the transient performance of HMG;based on the equations,theπ-type equivalent control model of the BIC is established.Next,the inertia power is actively transferred through the BIC according to the load fluctuation to compensate for the system’s inertia deficit.Secondly,theπ-VSG control utilizes small-signal analysis to investigate howthe fundamental parameters affect the overall stability of the HMG and incorporates power step response curves to reveal the relationship between the control’s virtual parameters and transient performance.Finally,the PSCAD/EMTDC simulation results show that theπ-VSG control effectively improves the immunity of AC frequency and DC voltage in the HMG system under the load fluctuation condition,increases the stability of the HMG system and satisfies the power-sharing control objective between the AC and DC subgrids.展开更多
Interconnection planning involving bi-directional converters(BdCs)is crucial for enhancing the reliability and robustness of hybrid alternating current(AC)/direct current(DC)microgrid clusters with high penetrations o...Interconnection planning involving bi-directional converters(BdCs)is crucial for enhancing the reliability and robustness of hybrid alternating current(AC)/direct current(DC)microgrid clusters with high penetrations of renewable energy resources(RESs).However,challenges such as the non-convex nature of BdC efficiency and renewable energy uncertainty complicate the planning process.To address these issues,this paper proposes a tri-level BdC-based planning framework that incorporates dynamic BdC efficiency and a data-correlated uncertainty set(DcUS)derived from historical data patterns.The proposed framework employs a least-squares approximation to linearize BdC efficiency and constructs the DcUS to balance computational efficiency and solution robustness.Additionally,a fully parallel column and constraint generation algorithm is developed to solve the model efficiently.Numerical simulations on a practical hybrid AC/DC microgrid system demonstrate that the proposed method reduces interconnection costs by up to 21.8%compared to conventional uncertainty sets while ensuring robust operation under all considered scenarios.These results highlight the computational efficiency,robustness,and practicality of the proposed approach,making it a promising solution for modern power systems.展开更多
The hybrid series-parallel microgrid attracts more attention by combining the advantages of both the series-stacked voltage and parallel-expanded capacity.Low-voltage distributed generations(DGs)are connected in serie...The hybrid series-parallel microgrid attracts more attention by combining the advantages of both the series-stacked voltage and parallel-expanded capacity.Low-voltage distributed generations(DGs)are connected in series to form the intra-string,and then multiple strings are interconnected in parallel.For the existing control strategies,both intra-string and inter-string depend on the centralized or distributed control with high communication reliance.It has limited scalability and redundancy under abnormal conditions.Alternatively,in this study,an intra-string distributed and inter-string decentralized control framework is proposed.Within the string,a few DGs close to the AC bus are the leaders to get the string power information and the rest DGs are the followers to acquire the synchronization information through the droop-based distributed consistency.Specifically,the output of the entire string has the active power−angular frequency(ω-P)droop characteristic,and the decentralized control among strings can be autonomously guaranteed.Moreover,the secondary control is designed to realize multi-mode objectives,including on/off-grid mode switching,grid-connected power interactive management,and off-grid voltage quality regulation.As a result,the proposed method has the ability of plug-and-play capabilities,single-point failure redundancy,and seamless mode-switching.Experimental results are provided to verify the effectiveness of the proposed practical solution.展开更多
A bipolar hybrid microgrid is a new topology which benefits from the advantages of both alternating current(AC)and direct current(DC)microgrids.Interlinking AC/DC converter is the key of this topology which has the fo...A bipolar hybrid microgrid is a new topology which benefits from the advantages of both alternating current(AC)and direct current(DC)microgrids.Interlinking AC/DC converter is the key of this topology which has the following characteristics:being able to provide two equal pole voltages in DC side;complying with the standards of current quality at AC side;being able to control active and reactive power independently in AC side,and transmitting bidirectional power.In this paper,two categories of power converters including single-stage and two-stage converters are proposed for this topology.A new cost-effective control strategy is added to the control of general grid-connected converter for each interlinking converter,and the control of autonomous DC-link pole voltage for both candidates is achieved.Detailed simulations based on the designed control strategies are conducted to validate the function of control strategies under the operation conditions of different DC sides.The performances of two selected interlinking converters with balanced and unbalanced DC loads are analyzed.Suggested power quality of microgrid and total harmonic distortion(THD)analysis are demonstrated in grid-tied and islanded modes.Eventually,semiconductor power loss simulations based on a closed-loop thermal network simulation are conducted.Thereby,the mutual effects of power loss and initial junction temperature are investigated.展开更多
Green hydrogen is considered one of the key technologies of the energy transition,as it can be used to store surpluses from renewable energies in times of high solar radiation or wind speed for use in dark lulls.This ...Green hydrogen is considered one of the key technologies of the energy transition,as it can be used to store surpluses from renewable energies in times of high solar radiation or wind speed for use in dark lulls.This paper examines the decarbonization potential of hydrogen for the heating industry.Worldwide,99%of hydrogen is produced from fossil fuels,because hydrogen derived from renew-able energy sources remains prohibitively expensive compared with its conventional counterpart.However,due to the expansion of renewable energy sources and the current energy crisis of conventional energy sources,hydrogen from renewable energy sources is becoming more and more economical.To optimize the efficiency of green hydrogen production and make it more price-competitive,the author simulates a hydrogen production plant consisting of a photovoltaic plant,a power grid,hydrogen storage,an electro-lyser,a natural gas purchase option,a district heating plant and households.Using the deep deterministic policy gradient algorithm from deep reinforcement learning,the plant is designed to optimize itself by simulating different production scenarios and deriving strategies.The connected district heating plant is used to map how hydrogen can be optimally used for heat supply.A demonstrable outcome of this paper is that the utilization of deep deterministic policy gradient,over the course of a full year,can result in a com-petitive production of hydrogen derived from renewable or stored energy sources for the heating industry as a natural gas substitute.展开更多
In the context of evolving energy needs and environmental concerns,efficient management of distributed energy resources within microgrids has gained prominence.This paper addresses the optimization of power flow manag...In the context of evolving energy needs and environmental concerns,efficient management of distributed energy resources within microgrids has gained prominence.This paper addresses the optimization of power flow management in a hybrid AC/DC microgrid through an energy management system driven by particle swarm optimization.Unlike traditional approaches that focus solely on active power distribution,our energy management system optimizes both active and reactive power allocation among sources.By leveraging 24-hour-ahead forecasting data encompassing load predictions,tariff rates and weather conditions,our strategy ensures an economically and environmentally optimized microgrid operation.Our proposed energy management system has dual objectives:minimizing costs and reducing greenhouse gas emissions.Through optimized operation of polluting sources and efficient utilization of the energy storage system,our approach achieved significant cost savings of~15%compared with the genetic algorithm coun-terpart.This was largely attributed to the streamlined operation of the gas turbine system,which reduced fuel consumption and associated expenses.Moreover,particle swarm optimization maintained the efficiency of the gas turbine by operating at~80%of its nominal power,effectively lowering greenhouse gas emissions.The effectiveness of our proposed strategy is validated through simu-lations conducted using the MATLAB®software environment.展开更多
Hybrid Petri nets(HPNs) are widely used to describe and analyze various industrial hybrid systems that have both discrete-event and continuous discrete-time behaviors. Recently,many researchers attempt to utilize them...Hybrid Petri nets(HPNs) are widely used to describe and analyze various industrial hybrid systems that have both discrete-event and continuous discrete-time behaviors. Recently,many researchers attempt to utilize them to characterize power and energy systems. This work proposes to adopt an HPN to model and analyze a microgrid that consists of green energy sources. A reachability graph for such a model is generated and used to analyze the system properties.展开更多
Present-day power conversion and conditioning systems focus on transferring energy from a single type of power source into a single type of load or energy storage system (ESS). While these systems can be optimized wit...Present-day power conversion and conditioning systems focus on transferring energy from a single type of power source into a single type of load or energy storage system (ESS). While these systems can be optimized within their specific topology (e.g. MPPT for solar applications and BMS for batteries), the topologies are not easily adapted to accept a wide range of power flow operating conditions. With a hybrid approach to energy storage and power flow, a system can be designed to operate at its most advantageous point, given the operating conditions. Based on the load demand, the system can select the optimal power source and ESS. This paper will investigate the feasibility of combining two types of power sources (main utility grid and photovoltaics (PV)) along with two types of ESS (ultra-capacitors and batteries). The simulation results will show the impact of a hybrid ESS on a grid-tied residential microgrid system performance under various operating scenarios.展开更多
随着可再生能源并网比例增加及需求侧负荷多样化,多微网系统在促进分布式能源消纳方面发挥关键作用。为实现多微网系统内源荷储之间的高效协同配合,提出一种考虑虚拟储能(virtual energy storage,VES)的多微网混合博弈模型。首先根据空...随着可再生能源并网比例增加及需求侧负荷多样化,多微网系统在促进分布式能源消纳方面发挥关键作用。为实现多微网系统内源荷储之间的高效协同配合,提出一种考虑虚拟储能(virtual energy storage,VES)的多微网混合博弈模型。首先根据空调负荷等效热力学特性、电动汽车充放电特性,构建基于电动汽车集群、空调负荷集群的虚拟储能模型。其次构建以多微网运营商为领导者,负荷聚合商、储能运营商为跟随者的主从博弈模型,并在主从博弈基础上引入多微网运营商中各微网间的合作博弈,促进微网间的端对端(peer-to-peer,P2P)电能交易,在合作收益分配问题中,引入基于非线性函数贡献度的纳什议价模型,实现更加公平的微网间利益分配。最后基于结合求解器的自适应差分进化算法以及交替方向乘子法求解所提出的模型。仿真结果表明,所提多微网混合博弈模型有效均衡了各主体的效益,同时提升了多微网运营商的效益,使多微网内分布式可再生能源消纳率提升至100%,实体储能的充放电量减少16%的同时向上级电网的购电量也减少44%,降低了对实体储能以及上级电网的依赖。展开更多
This study explores the feasibility of implementing a hybrid microgrid system powered by renewable energy sources.Including solar photovoltaics,wind energy,and fuel cells to ensure a reliable and sustainable electrici...This study explores the feasibility of implementing a hybrid microgrid system powered by renewable energy sources.Including solar photovoltaics,wind energy,and fuel cells to ensure a reliable and sustainable electricity supply for the SEKEM farm in WAHAT,Egypt.The study utilizes MATLAB/Simulink software to conduct simulations based on sun irradiation and wind speed data.Various control techniques,such as the proportional-integral(PI)controller,Fuzzy Logic Controller for PI tuning(fuzzy-PI),and neuro-fuzzy controllers,were evaluated to improve the performance of the microgrid.The results demonstrate that the Fuzzy-PI control strategy outperforms the alternative control systems,enhancing the overall dependability and long-term viability of energy provision.The hybrid system was integrated with a voltage source control(VSC)and fuzzy PI controller,which effectively addressed power fluctuations and improved the stability and reliability of the energy supply.Furthermore,it provides insightful information on how to design and implement a 100%renewable energy system,with the fuzzy PI controller emerging as a viable method of control that can guarantee the system’s resilience and outperform other approaches,such as the standalone PI controller and the neuro-fuzzy controller.展开更多
基金funded by“The Fourth Phase of 2022 Advantage Discipline Engineering-Control Science and Engineering”,grant number 4013000063.
文摘The rapid development of new energy power generation technology and the transformation of power electronics in the core equipment of source-grid-load drives the power system towards the“double-high”development pattern of“high proportion of renewable energy”and“high proportion of power electronic equipment”.To enhance the transient performance of AC/DC hybrid microgrid(HMG)in the context of“double-high,”aπtype virtual synchronous generator(π-VSG)control strategy is applied to bidirectional interface converter(BIC)to address the issues of lacking inertia and poor disturbance immunity caused by the high penetration rate of power electronic equipment and new energy.Firstly,the virtual synchronous generator mechanical motion equations and virtual capacitance equations are used to introduce the virtual inertia control equations that consider the transient performance of HMG;based on the equations,theπ-type equivalent control model of the BIC is established.Next,the inertia power is actively transferred through the BIC according to the load fluctuation to compensate for the system’s inertia deficit.Secondly,theπ-VSG control utilizes small-signal analysis to investigate howthe fundamental parameters affect the overall stability of the HMG and incorporates power step response curves to reveal the relationship between the control’s virtual parameters and transient performance.Finally,the PSCAD/EMTDC simulation results show that theπ-VSG control effectively improves the immunity of AC frequency and DC voltage in the HMG system under the load fluctuation condition,increases the stability of the HMG system and satisfies the power-sharing control objective between the AC and DC subgrids.
基金supported by the National Natural Science Foundation of China(72271213)the Shenzhen Science and Technology Program(JCYJ20220530143800001 and RCYX20221008092927070)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(2024A1515240024)the National Key Research and Development Program of China(2022YFB2403500).
文摘Interconnection planning involving bi-directional converters(BdCs)is crucial for enhancing the reliability and robustness of hybrid alternating current(AC)/direct current(DC)microgrid clusters with high penetrations of renewable energy resources(RESs).However,challenges such as the non-convex nature of BdC efficiency and renewable energy uncertainty complicate the planning process.To address these issues,this paper proposes a tri-level BdC-based planning framework that incorporates dynamic BdC efficiency and a data-correlated uncertainty set(DcUS)derived from historical data patterns.The proposed framework employs a least-squares approximation to linearize BdC efficiency and constructs the DcUS to balance computational efficiency and solution robustness.Additionally,a fully parallel column and constraint generation algorithm is developed to solve the model efficiently.Numerical simulations on a practical hybrid AC/DC microgrid system demonstrate that the proposed method reduces interconnection costs by up to 21.8%compared to conventional uncertainty sets while ensuring robust operation under all considered scenarios.These results highlight the computational efficiency,robustness,and practicality of the proposed approach,making it a promising solution for modern power systems.
基金supported by the Smart Grid-National Science and Technology Major Project(2025ZD0804500)the National Natural Science Foundation of China under Grant 52307232the Hunan Provincial Natural Science Foundation of China under Grant 2024JJ4055.
文摘The hybrid series-parallel microgrid attracts more attention by combining the advantages of both the series-stacked voltage and parallel-expanded capacity.Low-voltage distributed generations(DGs)are connected in series to form the intra-string,and then multiple strings are interconnected in parallel.For the existing control strategies,both intra-string and inter-string depend on the centralized or distributed control with high communication reliance.It has limited scalability and redundancy under abnormal conditions.Alternatively,in this study,an intra-string distributed and inter-string decentralized control framework is proposed.Within the string,a few DGs close to the AC bus are the leaders to get the string power information and the rest DGs are the followers to acquire the synchronization information through the droop-based distributed consistency.Specifically,the output of the entire string has the active power−angular frequency(ω-P)droop characteristic,and the decentralized control among strings can be autonomously guaranteed.Moreover,the secondary control is designed to realize multi-mode objectives,including on/off-grid mode switching,grid-connected power interactive management,and off-grid voltage quality regulation.As a result,the proposed method has the ability of plug-and-play capabilities,single-point failure redundancy,and seamless mode-switching.Experimental results are provided to verify the effectiveness of the proposed practical solution.
文摘A bipolar hybrid microgrid is a new topology which benefits from the advantages of both alternating current(AC)and direct current(DC)microgrids.Interlinking AC/DC converter is the key of this topology which has the following characteristics:being able to provide two equal pole voltages in DC side;complying with the standards of current quality at AC side;being able to control active and reactive power independently in AC side,and transmitting bidirectional power.In this paper,two categories of power converters including single-stage and two-stage converters are proposed for this topology.A new cost-effective control strategy is added to the control of general grid-connected converter for each interlinking converter,and the control of autonomous DC-link pole voltage for both candidates is achieved.Detailed simulations based on the designed control strategies are conducted to validate the function of control strategies under the operation conditions of different DC sides.The performances of two selected interlinking converters with balanced and unbalanced DC loads are analyzed.Suggested power quality of microgrid and total harmonic distortion(THD)analysis are demonstrated in grid-tied and islanded modes.Eventually,semiconductor power loss simulations based on a closed-loop thermal network simulation are conducted.Thereby,the mutual effects of power loss and initial junction temperature are investigated.
文摘Green hydrogen is considered one of the key technologies of the energy transition,as it can be used to store surpluses from renewable energies in times of high solar radiation or wind speed for use in dark lulls.This paper examines the decarbonization potential of hydrogen for the heating industry.Worldwide,99%of hydrogen is produced from fossil fuels,because hydrogen derived from renew-able energy sources remains prohibitively expensive compared with its conventional counterpart.However,due to the expansion of renewable energy sources and the current energy crisis of conventional energy sources,hydrogen from renewable energy sources is becoming more and more economical.To optimize the efficiency of green hydrogen production and make it more price-competitive,the author simulates a hydrogen production plant consisting of a photovoltaic plant,a power grid,hydrogen storage,an electro-lyser,a natural gas purchase option,a district heating plant and households.Using the deep deterministic policy gradient algorithm from deep reinforcement learning,the plant is designed to optimize itself by simulating different production scenarios and deriving strategies.The connected district heating plant is used to map how hydrogen can be optimally used for heat supply.A demonstrable outcome of this paper is that the utilization of deep deterministic policy gradient,over the course of a full year,can result in a com-petitive production of hydrogen derived from renewable or stored energy sources for the heating industry as a natural gas substitute.
文摘In the context of evolving energy needs and environmental concerns,efficient management of distributed energy resources within microgrids has gained prominence.This paper addresses the optimization of power flow management in a hybrid AC/DC microgrid through an energy management system driven by particle swarm optimization.Unlike traditional approaches that focus solely on active power distribution,our energy management system optimizes both active and reactive power allocation among sources.By leveraging 24-hour-ahead forecasting data encompassing load predictions,tariff rates and weather conditions,our strategy ensures an economically and environmentally optimized microgrid operation.Our proposed energy management system has dual objectives:minimizing costs and reducing greenhouse gas emissions.Through optimized operation of polluting sources and efficient utilization of the energy storage system,our approach achieved significant cost savings of~15%compared with the genetic algorithm coun-terpart.This was largely attributed to the streamlined operation of the gas turbine system,which reduced fuel consumption and associated expenses.Moreover,particle swarm optimization maintained the efficiency of the gas turbine by operating at~80%of its nominal power,effectively lowering greenhouse gas emissions.The effectiveness of our proposed strategy is validated through simu-lations conducted using the MATLAB®software environment.
基金supported by the Deanship of Scientific Research(DSR)King Abdulaziz University,Jeddah(23-135-35-HiCi)
文摘Hybrid Petri nets(HPNs) are widely used to describe and analyze various industrial hybrid systems that have both discrete-event and continuous discrete-time behaviors. Recently,many researchers attempt to utilize them to characterize power and energy systems. This work proposes to adopt an HPN to model and analyze a microgrid that consists of green energy sources. A reachability graph for such a model is generated and used to analyze the system properties.
文摘Present-day power conversion and conditioning systems focus on transferring energy from a single type of power source into a single type of load or energy storage system (ESS). While these systems can be optimized within their specific topology (e.g. MPPT for solar applications and BMS for batteries), the topologies are not easily adapted to accept a wide range of power flow operating conditions. With a hybrid approach to energy storage and power flow, a system can be designed to operate at its most advantageous point, given the operating conditions. Based on the load demand, the system can select the optimal power source and ESS. This paper will investigate the feasibility of combining two types of power sources (main utility grid and photovoltaics (PV)) along with two types of ESS (ultra-capacitors and batteries). The simulation results will show the impact of a hybrid ESS on a grid-tied residential microgrid system performance under various operating scenarios.
文摘随着可再生能源并网比例增加及需求侧负荷多样化,多微网系统在促进分布式能源消纳方面发挥关键作用。为实现多微网系统内源荷储之间的高效协同配合,提出一种考虑虚拟储能(virtual energy storage,VES)的多微网混合博弈模型。首先根据空调负荷等效热力学特性、电动汽车充放电特性,构建基于电动汽车集群、空调负荷集群的虚拟储能模型。其次构建以多微网运营商为领导者,负荷聚合商、储能运营商为跟随者的主从博弈模型,并在主从博弈基础上引入多微网运营商中各微网间的合作博弈,促进微网间的端对端(peer-to-peer,P2P)电能交易,在合作收益分配问题中,引入基于非线性函数贡献度的纳什议价模型,实现更加公平的微网间利益分配。最后基于结合求解器的自适应差分进化算法以及交替方向乘子法求解所提出的模型。仿真结果表明,所提多微网混合博弈模型有效均衡了各主体的效益,同时提升了多微网运营商的效益,使多微网内分布式可再生能源消纳率提升至100%,实体储能的充放电量减少16%的同时向上级电网的购电量也减少44%,降低了对实体储能以及上级电网的依赖。
文摘This study explores the feasibility of implementing a hybrid microgrid system powered by renewable energy sources.Including solar photovoltaics,wind energy,and fuel cells to ensure a reliable and sustainable electricity supply for the SEKEM farm in WAHAT,Egypt.The study utilizes MATLAB/Simulink software to conduct simulations based on sun irradiation and wind speed data.Various control techniques,such as the proportional-integral(PI)controller,Fuzzy Logic Controller for PI tuning(fuzzy-PI),and neuro-fuzzy controllers,were evaluated to improve the performance of the microgrid.The results demonstrate that the Fuzzy-PI control strategy outperforms the alternative control systems,enhancing the overall dependability and long-term viability of energy provision.The hybrid system was integrated with a voltage source control(VSC)and fuzzy PI controller,which effectively addressed power fluctuations and improved the stability and reliability of the energy supply.Furthermore,it provides insightful information on how to design and implement a 100%renewable energy system,with the fuzzy PI controller emerging as a viable method of control that can guarantee the system’s resilience and outperform other approaches,such as the standalone PI controller and the neuro-fuzzy controller.
