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Charge controller for solar panel based charging of lead-acid batteries
Korenčiak, Peter ; Štohl, Radek (oponent) ; Fiedler, Petr (vedoucí práce)
This thesis deals with the design and implementation of a charge controller for multiple lead-acid batteries to be used in a solar system. Such controller enables an independent connection and charge control for each of more batteries with possibly different age and parameters. It is in contrast with solutions with one connection for multiple batteries connected in parallel, where mixing different battery types or ages is not recommended. This controller offers very high scalability of energy storage in solar system. It is also possible to use older batteries together with new ones instead of having to replace the old batteries when their capacity falls below required level. The requirements, hardware and software design along with the implementation of such controller with 20A nominal output current for five 12V lead-acid batteries are discussed in detail in this thesis. Additional features, alternative designs and algorithms are discussed as well. An important part of the work concentrates on high current switch design, short circuit protection as well as circuit for DC current measurement. Correct functionality of the implemented controller has been verified by measurements.
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Cryptography on an embedded platform
Korenčiak, Peter ; Hynčica, Ondřej (oponent) ; Fiedler, Petr (vedoucí práce)
This bachelor thesis deals with adjusting parts of the public domain cryptographic library LibTomCrypt so that it can be used on an embedded platform Rabbit 3000. The hash functions MD5, SHA-1 and RIPEMD-128, the Blowfish cipher and CBC block cipher mode have been successfully ported to this platform. These algorithms have been analysed by measuring of the exectution time for the computational power requirements, especially with regard to the length of the input data. The abovementioned hash functions showed non-linear relationship between the execution time and the length of input, the graph of which is like that of a step function. The non-existence of the relationship to the data values was confirmed. The measurements with Blowfish cipher in CBC block cipher mode showed that inicialization of cipher is time consuming (it lasted almost one second on the hardware used) and that it does not depend on the keysize or length of input. The encryption and decryption itself showed a linear relationship to input data length. In the scope of this thesis there was also verification of correct function of SSL/TLS library from the producer of Rabbit microprocessor by creating a HTTPS server and verifying that secure connection with the web browser has been established. The library worked correctly according to manual without any significant problems.
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Cryptography on an embedded platform
Korenčiak, Peter ; Hynčica, Ondřej (oponent) ; Fiedler, Petr (vedoucí práce)
This bachelor thesis deals with adjusting parts of the public domain cryptographic library LibTomCrypt so that it can be used on an embedded platform Rabbit 3000. The hash functions MD5, SHA-1 and RIPEMD-128, the Blowfish cipher and CBC block cipher mode have been successfully ported to this platform. These algorithms have been analysed by measuring of the exectution time for the computational power requirements, especially with regard to the length of the input data. The abovementioned hash functions showed non-linear relationship between the execution time and the length of input, the graph of which is like that of a step function. The non-existence of the relationship to the data values was confirmed. The measurements with Blowfish cipher in CBC block cipher mode showed that inicialization of cipher is time consuming (it lasted almost one second on the hardware used) and that it does not depend on the keysize or length of input. The encryption and decryption itself showed a linear relationship to input data length. In the scope of this thesis there was also verification of correct function of SSL/TLS library from the producer of Rabbit microprocessor by creating a HTTPS server and verifying that secure connection with the web browser has been established. The library worked correctly according to manual without any significant problems.
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Charge controller for solar panel based charging of lead-acid batteries
Korenčiak, Peter ; Štohl, Radek (oponent) ; Fiedler, Petr (vedoucí práce)
This thesis deals with the design and implementation of a charge controller for multiple lead-acid batteries to be used in a solar system. Such controller enables an independent connection and charge control for each of more batteries with possibly different age and parameters. It is in contrast with solutions with one connection for multiple batteries connected in parallel, where mixing different battery types or ages is not recommended. This controller offers very high scalability of energy storage in solar system. It is also possible to use older batteries together with new ones instead of having to replace the old batteries when their capacity falls below required level. The requirements, hardware and software design along with the implementation of such controller with 20A nominal output current for five 12V lead-acid batteries are discussed in detail in this thesis. Additional features, alternative designs and algorithms are discussed as well. An important part of the work concentrates on high current switch design, short circuit protection as well as circuit for DC current measurement. Correct functionality of the implemented controller has been verified by measurements.
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