In this paper, a new control strategy of battery-ultracapacitor hybrid energy storage system (HESS) is proposed for hybrid electric drive vehicles (HEVs). Compared to the stand, alone battery system may not be suffici...In this paper, a new control strategy of battery-ultracapacitor hybrid energy storage system (HESS) is proposed for hybrid electric drive vehicles (HEVs). Compared to the stand, alone battery system may not be sufficient to satisfy peak demand periods during transients in HEVs, the ultracapacitor pack can supply or recover the peak power and it can be used in high C-rates. However, the problem of battery-ultracapacitor hybrid energy storage system (HESS) is how to interconnect the battery and ultracapacitor and how to control the power distribution. This paper reviewed some battery-ultracapacitor hybrid energy storage system topology and investigated the advantages and disadvantages, then proposed a new control strategy. The proposed control strategy can improve the system performance and ultracapacitor utilization, while also decreasing the battery pack size to avoid the thermal runaway problems and increase the life of the battery. The experiment results showed the proposed control strategy can improve 3% - 4% ultracapacitor utilization.展开更多
The large variability in wind output power can adversely impact local loads that are sensitive to poor power quality. To mitigate large swings in power, the wind turbine output power can be conditioned by using a smal...The large variability in wind output power can adversely impact local loads that are sensitive to poor power quality. To mitigate large swings in power, the wind turbine output power can be conditioned by using a small energy buffer. A power conditioner is developed to smooth the wind power output by utilizing the energy of an electrochemical capacitor, or ultracapacitor. The conditioner is based on a single phase voltage source inverter connected between the grid inter-connection point and the ultracapacitor. The VSI shunt inverter injects or absorbs active power from the line to smooth the wind power output by utilizing the short term storage capabilities of the ultracapacitor. The ultracapacitor is connected to the DC link through a bidirectional DC-DC converter. The bidirectional DC-DC converter and VSI are constructed and field tested on a Skystream 3.7 wind turbine installed at the Missouri University of Science & Technology.展开更多
Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative b...Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative braking system is designed and discussed.The system takes a unique ultracapacitor-only approach to energy storage system.The bi-directional bride DC?DC converter which regulates current flow to and from the ultracapacitor operates in two modes:boost and buck,depending on the direction of the flow.In order to provide constant input and output current at the ultracapacitor,this system uses a double proportional-integral(PI) control strategy in regulating the duty cycle of PWM to the DC?DC converter.The permanent magnet synchronous motor(PWSM) drive system is also studied.The space vector pulse width modulation(SVPWM) technique,along with a two-closed-loop vector control model,is adopted after detailed analysis of PMSM characteristics.The overall model and control strategy for this regenerative braking system is ultimately built and simulated under the MATLAB and Simulink environment.A test platform is built to obtain experimental results.Analysis of the results reveals that more than half of the gravitational potential energy can be recovered by this system.Simulation and experimentation results testify the validity of the double PI control strategy for interface circuit of ultracapacitor and SVPWM strategy for PMSM.展开更多
Based on the analysis of ultracapacitors efficiency and vehicle driving character, three conditions restricting the ultracapacitors charge/discharge time are derived. The study focuses on ultracapacitors specific desi...Based on the analysis of ultracapacitors efficiency and vehicle driving character, three conditions restricting the ultracapacitors charge/discharge time are derived. The study focuses on ultracapacitors specific design rules decided by charge/discharge time and how to integrate with battery packs and converter through ultracapacitors’ voltage and current double regulators. Through BFC6100-EV electric bus test, it is shown that the proposed method and control strategy are feasible and the system can effectively improve the bus dynamic performance and ability to receive braking energy effectively.展开更多
A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the contr...A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the control and sensor system.An electric energy storage system (ESS) is required which possesses high power density with good cycle life.Ultracapacitors which exhibit high power density and cycle life are considered as energy storage devices.Simulations based on a specific voyage condition indicate that ESS with ultracapacitors has positive effects on reducing the output power demand of PEMFC and lightening the power system.Experimental results show that the state of charge (SOC) is related to the capacitance and resistance in ultracapacitor ESS.展开更多
文摘In this paper, a new control strategy of battery-ultracapacitor hybrid energy storage system (HESS) is proposed for hybrid electric drive vehicles (HEVs). Compared to the stand, alone battery system may not be sufficient to satisfy peak demand periods during transients in HEVs, the ultracapacitor pack can supply or recover the peak power and it can be used in high C-rates. However, the problem of battery-ultracapacitor hybrid energy storage system (HESS) is how to interconnect the battery and ultracapacitor and how to control the power distribution. This paper reviewed some battery-ultracapacitor hybrid energy storage system topology and investigated the advantages and disadvantages, then proposed a new control strategy. The proposed control strategy can improve the system performance and ultracapacitor utilization, while also decreasing the battery pack size to avoid the thermal runaway problems and increase the life of the battery. The experiment results showed the proposed control strategy can improve 3% - 4% ultracapacitor utilization.
文摘The large variability in wind output power can adversely impact local loads that are sensitive to poor power quality. To mitigate large swings in power, the wind turbine output power can be conditioned by using a small energy buffer. A power conditioner is developed to smooth the wind power output by utilizing the energy of an electrochemical capacitor, or ultracapacitor. The conditioner is based on a single phase voltage source inverter connected between the grid inter-connection point and the ultracapacitor. The VSI shunt inverter injects or absorbs active power from the line to smooth the wind power output by utilizing the short term storage capabilities of the ultracapacitor. The ultracapacitor is connected to the DC link through a bidirectional DC-DC converter. The bidirectional DC-DC converter and VSI are constructed and field tested on a Skystream 3.7 wind turbine installed at the Missouri University of Science & Technology.
基金supported by National Key Technology Research and Development Program of China (Grant No. 2007BAF10B00)
文摘Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative braking system is designed and discussed.The system takes a unique ultracapacitor-only approach to energy storage system.The bi-directional bride DC?DC converter which regulates current flow to and from the ultracapacitor operates in two modes:boost and buck,depending on the direction of the flow.In order to provide constant input and output current at the ultracapacitor,this system uses a double proportional-integral(PI) control strategy in regulating the duty cycle of PWM to the DC?DC converter.The permanent magnet synchronous motor(PWSM) drive system is also studied.The space vector pulse width modulation(SVPWM) technique,along with a two-closed-loop vector control model,is adopted after detailed analysis of PMSM characteristics.The overall model and control strategy for this regenerative braking system is ultimately built and simulated under the MATLAB and Simulink environment.A test platform is built to obtain experimental results.Analysis of the results reveals that more than half of the gravitational potential energy can be recovered by this system.Simulation and experimentation results testify the validity of the double PI control strategy for interface circuit of ultracapacitor and SVPWM strategy for PMSM.
文摘Based on the analysis of ultracapacitors efficiency and vehicle driving character, three conditions restricting the ultracapacitors charge/discharge time are derived. The study focuses on ultracapacitors specific design rules decided by charge/discharge time and how to integrate with battery packs and converter through ultracapacitors’ voltage and current double regulators. Through BFC6100-EV electric bus test, it is shown that the proposed method and control strategy are feasible and the system can effectively improve the bus dynamic performance and ability to receive braking energy effectively.
基金Supported by the State Key Program of National Natural Science Foundation of China (No. 50835006)Science & Technology Support Planning Foundation of Tianjin (No. 09ZCKFGX03000)
文摘A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the control and sensor system.An electric energy storage system (ESS) is required which possesses high power density with good cycle life.Ultracapacitors which exhibit high power density and cycle life are considered as energy storage devices.Simulations based on a specific voyage condition indicate that ESS with ultracapacitors has positive effects on reducing the output power demand of PEMFC and lightening the power system.Experimental results show that the state of charge (SOC) is related to the capacitance and resistance in ultracapacitor ESS.
