As more and more distributed renewable energy resources connected to electric power grids,the conventional power system evolves into an integrated energy grid(IEG)in order to satisfy various types of energy demands.Th...As more and more distributed renewable energy resources connected to electric power grids,the conventional power system evolves into an integrated energy grid(IEG)in order to satisfy various types of energy demands.This paper proposes a model of the coordinated scheduling of energy resources(CSoERs)for distributed district heating and cooling systems(DHCs)in an IEG.The model takes into consideration both the dispatchable grid-connected generators and distributed renewable energy resources,such as wind energy,solar energy and natural gas.The objective is to minimize the operation costs in the IEG in order to satisfy not only the electrical loads but also the heating loads and cooling loads.Furthermore,an energy storage system for heating loads and cooling loads is also developed in the DHCs to improve the operation reliability in the distributed DHCs.Detailed simulation studies are carried out to verify the effectiveness of the CSoERs under two different operation scenarios:grid-connected scenario and stand-alone scenario.Simulation results demonstrate that the performance of the CSoERs contributes to significant energy saving and reliability operation in both grid-connected scenario and standalone scenario in the IEG.展开更多
Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn ...Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.展开更多
针对基于储能组中退役电池具有不同的衰减程度和电压,提出了一种适用于直流配电网的多退役电池组并联的新型拓扑及其控制方法。首先,分析了采用下垂控制的多退役电池储能组并联运行时母线电压下降特性;其次,提出了一种基于离散一致性的...针对基于储能组中退役电池具有不同的衰减程度和电压,提出了一种适用于直流配电网的多退役电池组并联的新型拓扑及其控制方法。首先,分析了采用下垂控制的多退役电池储能组并联运行时母线电压下降特性;其次,提出了一种基于离散一致性的二次电压恢复控制解决母线电压偏差;最后,对多退役电池储能组进行重组和功率分配,通过离散一致性算法选择健康状态(state of health,SoH)良好的单个退役电池投入储能组中优先输出;结合每个储能组中退役电池荷电状态(state of charge,SoC)分布情况,实时调节储能电池组的下垂系数,优化退役电池的SoH和实现SoC一致性。通过对包含3个退役电池储能组的直流配电网仿真和实验分析,验证了所提控制方法的有效性。展开更多
High intermittence of renewable energy resources(RESs)and restriction for greenhouse gas(GHG)emissions have significantly challenged the operations of traditional diesel generator(DG)based microgirds.This paper consid...High intermittence of renewable energy resources(RESs)and restriction for greenhouse gas(GHG)emissions have significantly challenged the operations of traditional diesel generator(DG)based microgirds.This paper considers an emission-free microgid with hybrid hydrogen-battery energy storage(HHBES)and proposes a coordinated operational strategy to minimize its daily operation costs.In addition to the electricity purchase costs in the day-ahead market and the operational costs of RESs,the total degradation cost of HHBES is also included in the cost calculation.The proposed operational strategy consists of two coordinated stages.At the day-ahead stage,the schedule for the tie-line power is exchanged with the main grid,the output power of the fuel cell(FC)and the input power of the electrolysis device(ED)are optimized under the worst case of uncertain power output from RESs and power demand from electricity loads(ELs).At the intra-day stage,the battery power is determined according to the short-term prediction for the power of RESs and ELs.The problem is formulated as a robust optimization model and solved by a two-level column-andconstraint-generation(C&CG)algorithm.Numerical simulations using Australian energy market operator(AEMO)data are carried out to validate the effectiveness of the proposed strategy.展开更多
In this paper,a dual droop-frequency diving coordinated control strategy is proposed for electric vehicle(EV)applications,where the hybrid energy storage system(HESS)with supercapacitors and batteries is integrated to...In this paper,a dual droop-frequency diving coordinated control strategy is proposed for electric vehicle(EV)applications,where the hybrid energy storage system(HESS)with supercapacitors and batteries is integrated to prolong the life time of storage elements.The dynamic power allocation between the supercapacitor and batteries are obtained through the voltage cascaded control,upon which the high and low frequency power fluctuation are absorbed by the supercapacitors and batteries respectively to fully exploit the advantages of the supercapacitors and batteries.Moreover,the power capacity is scaled up by connecting storage blocks in parallel.A dual droop control scheme for parallel-connected energy storage system and its operation principle is introduced on the aspect of current sharing characteristic and state-of-charging(SOC)management.After detailed analysis and formula derivation,the corresponding loop parameters are designed.Through this control method,the current sharing performance is ensured and each block makes the self-adaptive adjustment according to their SOC.Consequently,the load power can be shared effectively,which helps to avoid the over-charge/over-discharge operation and contributes to the life cycle of the energy storage system.Each module is autonomous controlled without the necessity of communication,which is easy,economic and effective to realize.Finally,the simulation and experimental results are exhibited to verify the effectiveness of the proposed control scheme.展开更多
基金supported by the State Key Program of National Natural Science of China(Grant No.51437006)Guangdong Innovative Research Team Program(No.201001 NO 104744201).
文摘As more and more distributed renewable energy resources connected to electric power grids,the conventional power system evolves into an integrated energy grid(IEG)in order to satisfy various types of energy demands.This paper proposes a model of the coordinated scheduling of energy resources(CSoERs)for distributed district heating and cooling systems(DHCs)in an IEG.The model takes into consideration both the dispatchable grid-connected generators and distributed renewable energy resources,such as wind energy,solar energy and natural gas.The objective is to minimize the operation costs in the IEG in order to satisfy not only the electrical loads but also the heating loads and cooling loads.Furthermore,an energy storage system for heating loads and cooling loads is also developed in the DHCs to improve the operation reliability in the distributed DHCs.Detailed simulation studies are carried out to verify the effectiveness of the CSoERs under two different operation scenarios:grid-connected scenario and stand-alone scenario.Simulation results demonstrate that the performance of the CSoERs contributes to significant energy saving and reliability operation in both grid-connected scenario and standalone scenario in the IEG.
基金supported by the National Key Research and Development Program of China(2022YFE0206300)the National Natural Science Foundation of China(22209047,U21A2081,22075074)+2 种基金Natural Science Foundation of Hunan Province(2020JJ5035)Hunan Provincial Department of Education Outstanding Youth Project(23B0037)Macao Science and Technology Development Fund(Macao SAR,FDCT-0096/2020/A2).
文摘Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.
文摘针对基于储能组中退役电池具有不同的衰减程度和电压,提出了一种适用于直流配电网的多退役电池组并联的新型拓扑及其控制方法。首先,分析了采用下垂控制的多退役电池储能组并联运行时母线电压下降特性;其次,提出了一种基于离散一致性的二次电压恢复控制解决母线电压偏差;最后,对多退役电池储能组进行重组和功率分配,通过离散一致性算法选择健康状态(state of health,SoH)良好的单个退役电池投入储能组中优先输出;结合每个储能组中退役电池荷电状态(state of charge,SoC)分布情况,实时调节储能电池组的下垂系数,优化退役电池的SoH和实现SoC一致性。通过对包含3个退役电池储能组的直流配电网仿真和实验分析,验证了所提控制方法的有效性。
基金The work was supported in part by T-RECs Energy Pte.Ltd.under Grand No.04IDS000719N014the National Natural Science Foundation of China(71801054)。
文摘High intermittence of renewable energy resources(RESs)and restriction for greenhouse gas(GHG)emissions have significantly challenged the operations of traditional diesel generator(DG)based microgirds.This paper considers an emission-free microgid with hybrid hydrogen-battery energy storage(HHBES)and proposes a coordinated operational strategy to minimize its daily operation costs.In addition to the electricity purchase costs in the day-ahead market and the operational costs of RESs,the total degradation cost of HHBES is also included in the cost calculation.The proposed operational strategy consists of two coordinated stages.At the day-ahead stage,the schedule for the tie-line power is exchanged with the main grid,the output power of the fuel cell(FC)and the input power of the electrolysis device(ED)are optimized under the worst case of uncertain power output from RESs and power demand from electricity loads(ELs).At the intra-day stage,the battery power is determined according to the short-term prediction for the power of RESs and ELs.The problem is formulated as a robust optimization model and solved by a two-level column-andconstraint-generation(C&CG)algorithm.Numerical simulations using Australian energy market operator(AEMO)data are carried out to validate the effectiveness of the proposed strategy.
文摘In this paper,a dual droop-frequency diving coordinated control strategy is proposed for electric vehicle(EV)applications,where the hybrid energy storage system(HESS)with supercapacitors and batteries is integrated to prolong the life time of storage elements.The dynamic power allocation between the supercapacitor and batteries are obtained through the voltage cascaded control,upon which the high and low frequency power fluctuation are absorbed by the supercapacitors and batteries respectively to fully exploit the advantages of the supercapacitors and batteries.Moreover,the power capacity is scaled up by connecting storage blocks in parallel.A dual droop control scheme for parallel-connected energy storage system and its operation principle is introduced on the aspect of current sharing characteristic and state-of-charging(SOC)management.After detailed analysis and formula derivation,the corresponding loop parameters are designed.Through this control method,the current sharing performance is ensured and each block makes the self-adaptive adjustment according to their SOC.Consequently,the load power can be shared effectively,which helps to avoid the over-charge/over-discharge operation and contributes to the life cycle of the energy storage system.Each module is autonomous controlled without the necessity of communication,which is easy,economic and effective to realize.Finally,the simulation and experimental results are exhibited to verify the effectiveness of the proposed control scheme.
