EPE Association: EPE 2011 - LS7b: Topic 15: Storage of Energy

EPE 2011 - LS7b: Topic 15: Storage of Energy
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 15: Non-rotating power generation and storage systems > EPE 2011 - LS7b: Topic 15: Storage of Energy

   [return to parent folder]

   Development of a Modular High-Power Converter System for Battery Energy Storage Systems
By Stephan THOMAS, Marco STIENEKER, Rik W. DE DONCKER [View]
[Download]

Abstract: The integration of storage systems into the grid is becoming increasingly important due to thegrowing amount of volatile power sources. This paper shows how to design a modular batteryenergy storage system (BESS) for medium voltage grids. Typically, this system is scalable inpower rated from 5 MW up to 100 MW with a storage capacity of several hours. Using powerelectronic building blocks (PEBBs) a converter for dc grids and ac grids can be built. In thispaper, the chosen topology for the ac solution is the cascaded cell converter. The focus isto determine the optimum number of levels, the modulation technique to avoid microcycles ofthe batteries and to present the efficiency. A formula to calculate the parasitic capacitance oflead-acid batteries is shown and verified by measurements, which is important for the design ofsuch a converter system. Moreover, a new charging strategy for LiFePO4 - the chosen batterytechnology for the proposed storage system - is introduced, which prolongs the battery’s life,reduces the charging time and decreases the life cycle cost. The proposed charging strategy andbattery technology compared to lead-acid batteries is also economically evaluated.

   Power Loss Evaluation of Voltage Equalisation Circuit for Series-connected Supercapacitors Energy Storage
By Ponggorn KULSANGCHAROEN, Christian KLUMPNER, Mohamed RASHED, Greg ASHER [View]
[Download]

Abstract: This paper investigates the various aspects of designing and exploiting a flyback type of regenerative voltage equalizer circuit for supercapacitor stacks consisting of multiple cells. The impact of circuit parameters (magnetising inductance, peak current), operating modes (constant switching frequency or constant peak current) and duration of equalising are investigated in detail on a predefined four supercapacitor cells stack from the point of view of energy efficiency and effectiveness of equalising. Finally, the performance of the active-regenerative equalising circuit is compared to the performance of an active-dissipative circuit, concluding that it offers better efficiency, performs a more effective voltage equalising and, due to using a single active device, may even be more economical to build.

   Thermoelectric Power Generation: Properties, Application and novel TCAD simulation
By Chris GOULD [View]
[Download]

Abstract: This paper documents the testing of commercial thermoelectric modules when they are connected for thermoelectric power generation, the design of a thermoelectric energy harvesting system, and the novel 3D TCAD simulation of a thermoelectric couple when it is connected for thermoelectric power generation. A standard thermoelectric module will generate a small amount of electrical power, typically in the milli-watt range, if a temperature difference is maintained between two sides of the device. With the addition of relatively simple electronic signal-conditioning techniques - for example low power step-up DC to DC conversion, coupled with electrical energy storage in supercapacitors, the electrical power output from a thermoelectric power generation system can be increased to a useful and stable level. The electrical power generated by a thermoelectric energy harvesting system, designed in this way, can be used to provide electrical power to other low power electronic systems - for example electronic sensors, low power microcontrollers, and replace or recharge batteries in many applications. The 3D TCAD simulation model of a thermoelectric couple successfully demonstrates the basic principle of thermoelectric power generation, and how the application of a temperature gradient to a thermoelectric couple results in a small amount of electrical power being generated at a load resistor. The 3D TCAD simulation model will enable further investigation in the future into different material structures, thermoelectric couple and module designs, and the improvement in thermoelectric performance and efficiency.

EPE 2011 - LS7b: Topic 15: Storage of Energy
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 15: Non-rotating power generation and storage systems > EPE 2011 - LS7b: Topic 15: Storage of Energy
	[return to parent folder]

	Development of a Modular High-Power Converter System for Battery Energy Storage Systems By Stephan THOMAS, Marco STIENEKER, Rik W. DE DONCKER	[View] [Download]
Abstract: The integration of storage systems into the grid is becoming increasingly important due to thegrowing amount of volatile power sources. This paper shows how to design a modular batteryenergy storage system (BESS) for medium voltage grids. Typically, this system is scalable inpower rated from 5 MW up to 100 MW with a storage capacity of several hours. Using powerelectronic building blocks (PEBBs) a converter for dc grids and ac grids can be built. In thispaper, the chosen topology for the ac solution is the cascaded cell converter. The focus isto determine the optimum number of levels, the modulation technique to avoid microcycles ofthe batteries and to present the efficiency. A formula to calculate the parasitic capacitance oflead-acid batteries is shown and verified by measurements, which is important for the design ofsuch a converter system. Moreover, a new charging strategy for LiFePO4 - the chosen batterytechnology for the proposed storage system - is introduced, which prolongs the battery’s life,reduces the charging time and decreases the life cycle cost. The proposed charging strategy andbattery technology compared to lead-acid batteries is also economically evaluated.

	Power Loss Evaluation of Voltage Equalisation Circuit for Series-connected Supercapacitors Energy Storage By Ponggorn KULSANGCHAROEN, Christian KLUMPNER, Mohamed RASHED, Greg ASHER	[View] [Download]
Abstract: This paper investigates the various aspects of designing and exploiting a flyback type of regenerative voltage equalizer circuit for supercapacitor stacks consisting of multiple cells. The impact of circuit parameters (magnetising inductance, peak current), operating modes (constant switching frequency or constant peak current) and duration of equalising are investigated in detail on a predefined four supercapacitor cells stack from the point of view of energy efficiency and effectiveness of equalising. Finally, the performance of the active-regenerative equalising circuit is compared to the performance of an active-dissipative circuit, concluding that it offers better efficiency, performs a more effective voltage equalising and, due to using a single active device, may even be more economical to build.

	Thermoelectric Power Generation: Properties, Application and novel TCAD simulation By Chris GOULD	[View] [Download]
Abstract: This paper documents the testing of commercial thermoelectric modules when they are connected for thermoelectric power generation, the design of a thermoelectric energy harvesting system, and the novel 3D TCAD simulation of a thermoelectric couple when it is connected for thermoelectric power generation. A standard thermoelectric module will generate a small amount of electrical power, typically in the milli-watt range, if a temperature difference is maintained between two sides of the device. With the addition of relatively simple electronic signal-conditioning techniques - for example low power step-up DC to DC conversion, coupled with electrical energy storage in supercapacitors, the electrical power output from a thermoelectric power generation system can be increased to a useful and stable level. The electrical power generated by a thermoelectric energy harvesting system, designed in this way, can be used to provide electrical power to other low power electronic systems - for example electronic sensors, low power microcontrollers, and replace or recharge batteries in many applications. The 3D TCAD simulation model of a thermoelectric couple successfully demonstrates the basic principle of thermoelectric power generation, and how the application of a temperature gradient to a thermoelectric couple results in a small amount of electrical power being generated at a load resistor. The 3D TCAD simulation model will enable further investigation in the future into different material structures, thermoelectric couple and module designs, and the improvement in thermoelectric performance and efficiency.