|
|
Worpllace for dynamic testring of solar cells.
Hanák, Kamil ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This work deals with method for characterization of photovoltaic solar cells based on evaluation of solar cell response to fast transients. The voltage of the cell in both forward and reverse polarisation was controlled by current pulse exciting. Real reverse breakdown voltage and exact value of serial resistance of the cell can be obtained easily by evaluation of the transient curves recorded by digital osciloscope. By negotiation of the time constants of the cell response to excitation in forward polarisation the lifetime of minority carriers in semiconductor bulk can be estimated.
|
|
|
Microplasma Noise as a Diagnostic Tool for PN Junctions of High-Voltage Rectifier Diodes
Raška, Michal ; Chobola, Zdeněk (referee) ; Hájek, Karel (referee) ; Koktavý, Pavel (advisor)
The doctoral thesis deals with diagnostics of local defects in PN junctions and brings new information about microplasma noise behaviour and its usage for the temperature changes detection inside PN junctions. Defects in PN junctions are the source of microplasma noise. There were deviations observed in microplasma noise from the common known rectangle shape pulses during the measurements. These deviations were correlated with the temperature change directly in the defect area and in the defect area surroundings. Generation and recombination coefficients are commonly thought to be constant. However, these coefficients were observed to be not stable with time and this effect is explained in this work. The doctoral thesis then focuses on the PN junction parameters determination in the case when it is not possible to define unambiguously whether it is abrupt or linearly graded PN junction. The most significant parameters which are to be determined are barrier capacity, diffusion voltage and depleted area width in dependence on the voltage. The correlation between local avalanche discharge in PN junction and negative differential resistance appearance on VA characteristics of reverse-biased diode was qualitatively verified. The last important point in the work is computer modelling of temperature behaviour in the defect area and its surroundings during local avalanche breakdown. Thus the method of real diodes heating area parameters determination was introduced.
|
|
|
Dynamic testing of solar cells
Šneidr, Radim ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
The content of this thesis is the validation of the method of dynamic testing of solar photovoltaic cells. Testing methods for determining the parameters of the photovoltaic cell replacement scheme has been verified through testing a set of crystalline silicon photovoltaic cells. To accelerate the diffusion capacity measurement and to improve reproducibility of the measurement we propose new method of determining the time constant for diffusion capacitance using a combination of two short pulses. For this method of measurement new scheme for dynamic tester timing has been proposed and implemented.
|
|
| |
|
|
Capacitance measurement of high-voltage PN junctions
Derishev, Anton ; Kosina, Petr (referee) ; Boušek, Jaroslav (advisor)
The work deals with the capacitance measurement of high-voltage PN junctions. The work is divided into theoretical and practical parts. The theoretical part presents insight into the fundamental properties of PN junctions and methods for measuring of the capacitance of PN junctions, primarily by C-V measurement. In the practical part, several kinds of measuring circuits are introduced and a suitable method of measurement is found. The calculations of basic parameters - the width of the base and resistivity are presented and discussed. The results were compared with the values obtained by calculation from the technological parameters of the junction.
|
|
|
Microplasma Noise as a Diagnostic Tool for PN Junctions of High-Voltage Rectifier Diodes
Raška, Michal ; Chobola, Zdeněk (referee) ; Hájek, Karel (referee) ; Koktavý, Pavel (advisor)
The doctoral thesis deals with diagnostics of local defects in PN junctions and brings new information about microplasma noise behaviour and its usage for the temperature changes detection inside PN junctions. Defects in PN junctions are the source of microplasma noise. There were deviations observed in microplasma noise from the common known rectangle shape pulses during the measurements. These deviations were correlated with the temperature change directly in the defect area and in the defect area surroundings. Generation and recombination coefficients are commonly thought to be constant. However, these coefficients were observed to be not stable with time and this effect is explained in this work. The doctoral thesis then focuses on the PN junction parameters determination in the case when it is not possible to define unambiguously whether it is abrupt or linearly graded PN junction. The most significant parameters which are to be determined are barrier capacity, diffusion voltage and depleted area width in dependence on the voltage. The correlation between local avalanche discharge in PN junction and negative differential resistance appearance on VA characteristics of reverse-biased diode was qualitatively verified. The last important point in the work is computer modelling of temperature behaviour in the defect area and its surroundings during local avalanche breakdown. Thus the method of real diodes heating area parameters determination was introduced.
|
|
|
Capacitance measurement of high-voltage PN junctions
Derishev, Anton ; Kosina, Petr (referee) ; Boušek, Jaroslav (advisor)
The work deals with the capacitance measurement of high-voltage PN junctions. The work is divided into theoretical and practical parts. The theoretical part presents insight into the fundamental properties of PN junctions and methods for measuring of the capacitance of PN junctions, primarily by C-V measurement. In the practical part, several kinds of measuring circuits are introduced and a suitable method of measurement is found. The calculations of basic parameters - the width of the base and resistivity are presented and discussed. The results were compared with the values obtained by calculation from the technological parameters of the junction.
|
|
|
Dynamic testing of solar cells
Šneidr, Radim ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
The content of this thesis is the validation of the method of dynamic testing of solar photovoltaic cells. Testing methods for determining the parameters of the photovoltaic cell replacement scheme has been verified through testing a set of crystalline silicon photovoltaic cells. To accelerate the diffusion capacity measurement and to improve reproducibility of the measurement we propose new method of determining the time constant for diffusion capacitance using a combination of two short pulses. For this method of measurement new scheme for dynamic tester timing has been proposed and implemented.
|
|
|
Worpllace for dynamic testring of solar cells.
Hanák, Kamil ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This work deals with method for characterization of photovoltaic solar cells based on evaluation of solar cell response to fast transients. The voltage of the cell in both forward and reverse polarisation was controlled by current pulse exciting. Real reverse breakdown voltage and exact value of serial resistance of the cell can be obtained easily by evaluation of the transient curves recorded by digital osciloscope. By negotiation of the time constants of the cell response to excitation in forward polarisation the lifetime of minority carriers in semiconductor bulk can be estimated.
|
|
| |
guest ::
