Investigation into IGBT dV/dt during turn-off and its temperature dependence

In many power converter applications, particularly those with high variable loads, such as traction and wind power, condition monitoring of the power semiconductor devices in the converter is considered desirable. Monitoring the device junction temperature in such converters is an essential part of this process. In this paper, a method for measuring the insulated gate bipolar transistor (IGBT) junction temperature using the collector voltage dV/dt at turn-OFF is outlined. A theoretical closed-form expression for the dV/dt at turn-OFF is derived, closely agreeing with experimental measurements. The role of dV/dt in dynamic avalanche in high-voltage IGBTs is also discussed. Finally, the implications of the temperature dependence of the dV/dt are discussed, including implementation of such a temperature measurement technique. © 2006 IEEE.

IGBT series connection under Active Voltage Control with temporary clamp

This paper presents the use of an Active Voltage Control (AVC) technique for balancing the voltages in a series connection of Insulated Gate Bipolar Transistors (IGBTs). The AVC technique can control the switching trajectory of an IGBT according to a pre-set reference signal. In series connections, every series connected IGBT follows the reference and so that the dynamic voltage sharing is achieved. For the static voltage balancing, a temporary clamp technique is introduced. The temporary clamp technique clamps the collector-emitter voltage of all the series connected IGBTs at the ideal voltage so that the IGBTs will share the voltage evenly. © 2012 IEEE.

Improving discharge characteristics of indirect integral collector storage systems with multi-element storage

Desired performance of unpressurized integral collector storage systems hinges on the appropriate selection of storage volume and the immersed heat exchanger. This paper presents analytical results expressing the relation between storage volume, number of heat exchanger transfer units and temperature limited performance. For a system composed of a single storage element, the limiting behavior of a perfectly stratified storage element is shown to be superior to a fully-mixed storage element, consistent with more general analysis of thermal storage. Since, however, only the fully-mixed limit is readily obtainable in a physical system, the present paper also examines a division of the storage volume into separate compartments. This multi-element storage system shows significantly improved discharge characteristics as a result of improved elemental area utilization and temperature variation between elements, comparable in many cases to a single perfectly-stratified storage element. In addition, the multi-element system shows increased robustness with respect to variations in heat exchanger effectiveness and initial storage temperature.

Parameters influencing the performance of an IGBT gate drive

This paper presents an improvement of an IGBT gate drive implementing Active Voltage Control (AVC), and investigates the impact of various parameters affecting its performance. The effects of the bandwidths of various elements and the gains of AVC are shown in simulation and experimentally. Also, the paper proposes connecting a small Active Snubber between the IGBT collector and its gate integrated within the AVC. The effect of this snubber on enhancing the stability of the gate drive is demonstrated. It will be shown that using a wide bandwidth operational amplifier and integrating the Active Snubber within the gate drive reduces the minimum gate resistor required to achieve stability of the controller. Consequently, the response time of the IGBT to control signals is significantly reduced, the switching losses then can be minimised and, hence, the performance of gate drive as whole is improved. This reflects positively on turn-off and turn-on transitions achieving voltage sharing between the IGBTs connected in series to construct a higher voltage switch, making series IGBTs a feasible practice. ©2008 IEEE.