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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Charge Equalization of Batteries in Serial Power Modules

Hong, Wei 03 August 2010 (has links)
The charge equalization for the battery power source with battery power modules (BPMs) in series is presented in the thesis. The bidirectional power converters in BPMs are able to serve as chargers with buck conversion during the charging stage. Even though connected in series, all modules can substantially be operated individually, retaining the advantages of independent operation, such as flexible control, easy protection, simple maintenance, and favorable battery power management. Investigation results indicate that automatic charge equalization is possible for the discontinuous conduction mode (DCM) operation. On the other hand, charge equalization can be achieved much faster by individually regulating the charging currents at the continuous conduction mode (CCM). According to the analyzed results, an equalization strategy is proposed to solve the charge imbalance problem by scheduling the individual battery current. Experiments are carried out to demonstrate the effectiveness of charge equalization.
2

Operation of Battery Power Modules with Serial Connection

Hu, Jin-shin 20 July 2009 (has links)
This thesis presents a novel configuration of battery power by the outputs with serial connection of battery power modules (BPMs) for high voltage level loads. As compared to the conventional application of series-connected battery bank, this configuration operates the BPMs individually, and thus has the advantages of flexible control, convenient maintenance, and easily favorable battery management. The associated converter is equipped to a single battery pack, so that has lower component stresses leading to a higher circuit efficiency. The operation and the design of a lead-acid battery power with series boost-typed BPMs are illustrated. The operation and the design of the converter are illustrated. The control of the power converters is accomplished by a complex programmable logic device (CPLD). To improve the converter efficiency, the technique of synchronous rectification is introduced. For the BPMs designed for discontinuous conduction mode (DCM) operation, charge equalization can be automatically achieved under the same duty-ratio, but is adequate only for batteries with a small difference. On the other hand, charge equalization for the BPMs with continuous conduction mode (CCM) can easily be accomplished by regulating the duty-ratios of the converters.
3

I-U charakteristiky fotovoltaických modulů spojovaných paralelně a do série / I-V characteristic on photovoltaic modules connected in parallel and in serial

Láník, Lukáš January 2011 (has links)
In mentioned theses there are described the basic tenets of the photovoltaic panels operation. There is described the progress of the photovoltaic panels. Theses is focused on the theoretical knowledges about the equivalent circuits and their aplication in the proposed simulation system. The goal of theses is to create the surroundings in the program Agilent VEE Pro 8.0 and to create the program for the simulation of the serial and paralel conjunction of the photovoltaic panels. The resultant program enables the simulation of the I – V and P – V characteristics of the real photovoltaic panels.
4

Pohon sériovým zapojením rotačních hydromotorů / Drive system by serial connection of rotary hydromotors

Pokorný, Pavel January 2017 (has links)
The thesis deals with the problem of large-capacity manipulation of large forgings with forging manipulator. It describes current techniques, their characteristics, advantages and disadvantages. Based on the analysis of these techniques, the thesis introduces design of the connection of the hydraulic circuit for the drive of the traveling traction wheels of the forging manipulator QKK 100 by ŽĎAS a.s. focusing on simplicity, trouble-free operation, efficiency, economy, change of speed and torque, and possibility of modification according to the current load.
5

Aplikace ultrakapacitorů v dopravních systémech / Application of Ultracapacitors in Traffic Systems

Kalina, Emil January 2008 (has links)
The work deals with relatively new components allowing electric energy accumulation – ultracapacitors. It focuses on their application in traffic systems – in independent electric vehicles. Design and verification of a system with ultracapacitor and DC/DC adaptive converter was done. Control of the adaptive converter modifies very positively the time wafeform of the traction accumulator current during the drive cycle. The designed connection of ultracapacitor and DC/DC converter implemented in the drive structure of experimental electric vehicle with induction machine contributes to increment the action radius of the vehicle by 16% (determined by experimental verification). This result was achived particularly by limitation of traction accumulator current peaks, And by more effective storage of energy gained by recuperative braking of the vehicle as well. The core of the system is a control of the adaptive converter in order to provide an active filtration of the accumulator’s current to its long-period mean value, i.e. elimination of current (power) peaks. These are caused by acceleration from non-zero initial vehicle speed or by recuperative braking. This is done by a subsidiary current loop. The converter has a superior voltage regulation loop, which sets in long-time period the voltage of ultracapacitors to the proper value – indirectly dependent on the speed of the vehicle. This ensures the appropriate energy management of the ultracapacitor. In the following, properties of test set of ultracapacitors were verified. Finally, methods of suppression of capacity variability influence in series connection of these components were compiled and critically reviewed.

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