Investigation of High Temperature Operation Emitter Turn Off Thyristor (ETO) and Electro Thermal Design of Heatpipe Based High Power Voltage Source Converter Using ETO.
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Published: 2004
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DOWNLOAD EBOOKThe Emitter Turn Off Thyristor (ETO) is an emerging high power device that can be considered as a Mosfet-GTO hybrid. It is very suitable for high power applications due to many of its significant advantages in terms of usability and performance benefits. It combines the advantages of simplified control and improved switching performance. This thesis is focused on firstly investigating the loss characteristics of the ETO with variation in operating junction temperature. The switching loss, leakage loss and conduction loss of the ETO are recorded as a function of junction temperature in order to gain a better understanding of the thermal performance. Switching loss and conduction loss are found to have a linear dependence on temperature, whereas leakage loss is dependent exponentially on junction temperature. An effort is made in order to understand what limits the operation of semiconductor devices beyond a certain temperature limit. All this is then combined to develop a closed loop thermal model which is used to study the thermal stability. Thermal instability at high temperatures is caused primarily by the large leakage current, which rises exponentially with rise in temperature. Thermal stability can be maintained as long as the change rate of losses remains low enough such that the losses can be carried out of the switching junction of the device by means of the thermal conductance. This condition and the loss characteristics were used to predict the high temperature operating limit of the ETO. It is seen that due to the excellent loss characteristics of the device and due to the low thermal resistance from the junction to ambient, that the ETO should be capable of operating at temperatures well above 160 Degrees Celsius. Tests are done on the ETO in order to corroborate this theory and calculations Multilevel converters have become an important technology in high-power applications, especially for Flexible AC transmission system (FACTS) applications. In this th.
