19-02-2015, 09:37 PM
We want a MATLAB code to remove cloud from a satellite image.
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artificial heart seminars report download
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We want a MATLAB code to remove cloud from a satellite image.
28-03-2017, 09:47 AM
The artificial heart now in use, like the natural heart that is designed to replace, is a four-chamber device to pump blood. Such circulatory assisting electrical devices, such as artificial cardiac or ventricular assist devices, generally use a brushless DC motor as their pump. They require 12-35 watts to operate and can be powered by a portable battery and a dc-dc converter.
It would be desirable to transfer electrical energy to these circulatory assist devices transcutaneously without rupturing the skin. This technique would require a power supply that uses a transcutaneous transformer to drive the motor, the circulatory assistance device. The secondary of this transformer would be implanted under the skin, and the primary would be placed above the secondary, external to the body. The distance between the transformer windings would be approximately equal to the thickness of the patient's skin, nominally between 1-2 cm. This spacing can not be assumed constant; The alignment of the cores and the distance between them would certainly vary during the operation.
A transformer with a large (1-2 cm) space between the primary and the secondary has large leakage inductances. In this application, the coupling coefficient k oscillates approximately between 0.1 and 0.4. This causes the leakage inductances of the same order of magnitude and generally larger than the magnetizing inductance. Therefore, the voltage transfer gain is very low, and a significant portion of the primary current will flow through the magnetizing inductance. The large circulation current through the magnetizing inductance results in poor efficiency.
It has been reported that an dc-dc converter employing secondary side resonance alleviates the problems by decreasing the secondary side impedance using a resonant circuit. Although the circulation current is reduced, the voltage transfer gain varies widely as the coupling coefficient varies. Thus, the characteristics of the advantages are reduced as the coupling coefficient is diverted to a designated value.
This work presents the compensation of the leakage inductances on both sides of the transcutaneous transformer. This converter offers significant improvements over the converter presented in the following aspects.
• The high voltage gain with small relative variation with respect to the load change, as well as the variation of the coupling coefficient of the transformer, reduces the operating frequency range and minimizes the size of the transcutaneous transformer.
• Higher efficiency-minimizing the magnetizing inductance circulation current and zero voltage switching (ZVS) of the primary switches and the zero current switching (ZCS) of the secondary rectifier diodes improves efficiency, especially on the side Secondary (inside the body).
It presents a design procedure that allows a variable output power, as well as an air gap and a variable misalignment. The theoretical analysis is verified by an experimental converter that transfers 12-48 watts through a gap of 1-2 cm. In addition, the feedback control scheme is presented which processes the signal detected secondarily to the primary switches transcutaneously.
It would be desirable to transfer electrical energy to these circulatory assist devices transcutaneously without rupturing the skin. This technique would require a power supply that uses a transcutaneous transformer to drive the motor, the circulatory assistance device. The secondary of this transformer would be implanted under the skin, and the primary would be placed above the secondary, external to the body. The distance between the transformer windings would be approximately equal to the thickness of the patient's skin, nominally between 1-2 cm. This spacing can not be assumed constant; The alignment of the cores and the distance between them would certainly vary during the operation.
A transformer with a large (1-2 cm) space between the primary and the secondary has large leakage inductances. In this application, the coupling coefficient k oscillates approximately between 0.1 and 0.4. This causes the leakage inductances of the same order of magnitude and generally larger than the magnetizing inductance. Therefore, the voltage transfer gain is very low, and a significant portion of the primary current will flow through the magnetizing inductance. The large circulation current through the magnetizing inductance results in poor efficiency.
It has been reported that an dc-dc converter employing secondary side resonance alleviates the problems by decreasing the secondary side impedance using a resonant circuit. Although the circulation current is reduced, the voltage transfer gain varies widely as the coupling coefficient varies. Thus, the characteristics of the advantages are reduced as the coupling coefficient is diverted to a designated value.
This work presents the compensation of the leakage inductances on both sides of the transcutaneous transformer. This converter offers significant improvements over the converter presented in the following aspects.
• The high voltage gain with small relative variation with respect to the load change, as well as the variation of the coupling coefficient of the transformer, reduces the operating frequency range and minimizes the size of the transcutaneous transformer.
• Higher efficiency-minimizing the magnetizing inductance circulation current and zero voltage switching (ZVS) of the primary switches and the zero current switching (ZCS) of the secondary rectifier diodes improves efficiency, especially on the side Secondary (inside the body).
It presents a design procedure that allows a variable output power, as well as an air gap and a variable misalignment. The theoretical analysis is verified by an experimental converter that transfers 12-48 watts through a gap of 1-2 cm. In addition, the feedback control scheme is presented which processes the signal detected secondarily to the primary switches transcutaneously.
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