Eric Carroll

IGCT technology baseline and future opportunities

Commercially introduced in 1997, the IGCT has rapidly progressed into the main areas of high power electronics, namely: industrial drives, traction and energy management. Its simultaneous expansion towards higher and lower powers in such a short period of time was made possible by drawing on technologies derived from years of work on both GTOs and IGBTs. These technologies include anode and buffer-layer designs, lifetime profiling, separation technology for monolithic diode integration and junction passivation techniques. Asymmetric, reverse conducting and symmetric devices have become available to meet expanding application needs. The future potential especially in respect of 10 kV and dual gate devices is discussed. Diversified applications will require standardised components and the Power Electronic Building Blocks will have to become reality if cost expectations are to be met. The paper outlines the trends and opportunities for meeting PEBB goals and shows the newest very high power PEBB, developed with the Office of Naval Research especially for T&D applications, with simple supply on potential of series connected IGCTs.

A 6.5 kV IGBT module with very high safe operating area

A new 6.5 kV IGBT module is presented. This module, using high voltage soft-punch-through technology exhibits an exceptionally high reverse bias safe operating area and withstands dynamic avalanche up to its rated voltage. This capability allows the module to be operated with a gate resistance 10 times lower than present generations of 6.5 kV modules of the same nominal rating, allowing fast turn-off and hence reduced turn-off losses. The chip technology is briefly described and detailed test results highlighting the smooth switching characteristics, extremely safe operating areas and high tolerance to stray inductance is presented. The importance of fast switching through low values of gate resistance is explained in terms of loss-reduction, gate-drive simplification and good dynamic current sharing between chips within the module.

Design, test and characteristics of 10 kV IGCTs

This paper describes the design, experimental investigations and the characteristics of 10 kV IGCTs for 6 kV-7.2 kV applications. Compared to a series connection of two or three IGCTs and inverse diodes in a three level neutral point clamped voltage source converter 10 kV IGCTs and diodes offer several attractive characteristics such as drastically increased reliability due to a substantially reduced component count, a simpler and more compact mechanical and thermal design and thus reduced converter costs. The design of 10 kV IGCTs as well as the test set up are discussed. Measurements of the blocking-, on-state- and switching behaviour are the basis for a detailed description of the device performance. The technology trade off of 10 kV IGCTs is addressed to enable an application specific optimization of the IGCT design for low and high switching frequency applications (e.g. railway interties and medium voltage drives).