IGBT-based Converters Research Articles

Design Issues of Redundant Protection and Supervision System for the Special Purpose Power Converters

This paper addresses problems related to the design and implementation of a fault detection and protection system for high-voltage (HV) NPT IGBT-based converters. An isolated half-bridge power converter topology is investigated, which seems to be very attractive for the high-power electronic converters due to its overall simplicity, small component count and low realization costs. This converter is to be applied in rolling stock with its demanding reliability and safety requirements. Clearly, the robust control and protection system is essential.

Investigation of Harmonics Present in Three-Phase Auxiliary Converter Used in the Locomotives of Indian Railways

The presence of harmonics in locomotives used in Indian Railways has started to become one of the major concerns during the last few years. The cause of harmonics distortions in these locomotives is due to the increase in the use of power electronics devices, wherein the introduction of GTO and IGBT-based locomotives have brought up technological advancement in railways, while on the other hand it have its own certain limitations as well. Hence, the study was carried out on oil cooling blowers and traction motor blowers used in a locomotive which uses GTO and IGBT-based converters. This paper presents the analysis of current harmonics which were recorded using a current clamp and DSO.

Digitally Controlled Gate Current Source-Based Active Gate Driver for Silicon Carbide MOSFETs

Silicon carbide (SiC) MOSFETs are viable alternatives for silicon (Si) insulated-gate bipolar transistors (IGBTs). However, direct retrofitting of SiC MOSFETs in Si IGBT-based converters is not feasible due to the presence of a higher amount of parasitic inductance. A large voltage and current overshoot along with oscillation are noticed in such attempts as SiC MOSFETs switch very fast. An active gate driver (AGD) can meet the conflicting requirements of faster switching speed and lower overshoot and ringing. A switched current source-based AGD is designed and extensively tested in a 50-kVA voltage source inverter made with SiC MOSFET power modules. The control methodology is discussed and the experimental results are presented in this article.

Application of EMR Signature in Health Assessment and Monitoring of IGBT-Based Converters

In this paper, a non-invasive method based on electromagnetic radiation (EMR) signature is proposed for the health assessment of the converters. Converters use insulated gate bipolar transistor (IGBT) because of its robustness. However, it suffers from internal degradation due to the rapid power cycle and thermal stress. Degradation of IGBT primarily increases the turn- off time as a consequence of elevated junction temperature. The coupling of IGBT with the parasitics of the circuit results in EMR and depends on the turn- off time of IGBT. It has been found that the EMR signature reduces with the increase in turn- off time. This concept is taken forward for the health assessment of the converters. However, in a practical scenario, the EMR generated from multiple converters get mixed up. This is commonly known as a problem of near-field source localization. We use a uniform linear array to capture the EMR signals near the converters. Subsequently, ESPRIT and MUSIC algorithms are used to localize all the converters. An inverse transformation of the localization algorithm separates the EMR signature of all the individual converters. The proposed health assessment algorithm computes the degradation level of converters, and the experimental results validate the proposed approach.