Techniques for Connecting IGBT Modules and Loss Mitigation: A Survey

The circuit elements which are able to handle high power play a pivotal role in power electronics industry. By connecting these devices in series or parallel, high power ratings may be achieved based upon their application. The ability of Insulated Gate Bipolar Transistors (IGBTs) to handle high power is well known, however, they might experience losses during switching. Another challenge in this regard is the aspect of voltage and current balancing in series and parallel connections, respectively. Various techniques have been proposed in literature to achieve this voltage/current balance in IGBTs. Most commonly used techniques for voltage balancing are active gate control method, snubber circuits and clamping circuits. Moreover, widely used approaches to achieve current balancing are active gate control, impedance balancing and derating factor. In this work, we discuss the major failure mechanisms and the techniques to handle such failures. Furthermore, we also dilate upon the open circuit and short circuit fault detection methods. With an aim of minimizing the IGBT connection problems we explain the viable approaches, the methods to reduce the switching losses and the techniques to handle failures in series and parallel combinations.