Insulated-gate Bipolar Transistors Turn Research Articles

Noncontact Monitoring of IGBT Turn-OFF Time Using PWM Switching Ringing for Inverter-Fed Machine Systems

Turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> time is an important condition parameter for insulated gate bipolar transistor (IGBT), which could provide useful information on the device junction temperature and its state of health. Currently, it is measured directly from the IGBT collector-emitter voltage <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ce</sub> or indirectly from the gate side, which may cause problems of safety and complexity for a power converter operating in a harsh electromagnetic environment. To address the challenges, this article proposes a noncontact method to monitor the IGBT turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> time from the PWM switching ringing in the converter output current. First, a phenomenon is observed that there are two switch-over points in the switching ringing current corresponding to the transition of IGBT turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> voltage. Analytical analysis is performed with a high-frequency (HF) equivalent circuit to investigate the mechanism of the one-to-one temporal relationship. Then, the noncontact condition monitoring (CM) scheme including the HF switching ringing current sensor and the framework of CM system is devised. Finally, experimental work is carried out to validate the theoretical analysis and the effectiveness of the method. Research results show that the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> time of multi-IGBTs can be effectively extracted at the terminal of converter during system normal operation with electrically isolated safety.

Effective Magnetic Component Design of Three-Phase Dual-Active-Bridge Converter for LVDC Distribution System

To improve the power conversion efficiency of a three-phase dual-active-bridge (3P-DAB) converter for low-voltage direct current distribution systems, a practical design methodology is proposed. Commonly, the 3P-DAB converter is designed by only specification, such as the rated power, input/output voltage, and frequency. However, using the conventional design method, the efficiency is low under heavy load conditions due to the high conduction loss. In this article, based on the practical power loss analysis, the effective design methodology of the coupling inductance in the 3P-DAB converter is proposed, focusing on power conversion efficiency. It can mitigate the drawbacks of the common design by reducing the peak and rms phase current and the insulated-gate bipolar transistors turn- off current. Experimental results verify the validity of the proposed design methodology and controller using a 25-kW prototype 3P-DAB converter.

Compressed Sensing Method for IGBT High-Speed Switching Time On-Line Monitoring

Condition monitoring (CM) has been considered as a promising technique to improve the reliability of insulated gate bipolar transistors (IGBTs). Among various condition parameters, switching time is a good health status indicator to detect IGBT failures. However, on-line monitoring of the IGBT high-speed switching time is still difficult in practice due to the requirement of the extremely high sampling rate for signal acquisition. To overcome the technical difficulty, this paper provides an innovative compressed sensing (CS) method to achieve equivalent sampling performance for high-speed IGBT switching time monitoring with a lower sampling rate. By utilizing the sparse characteristics of an IGBT switching signal, the sampling rate in the CS method could be far less than the traditional Nyquist sampling rate. To clarify the method, the CM mechanism using IGBT switching time is first analyzed. Then, three key points in the CS method are studied, i.e., the selection of sparsifying basis, the design of a measurement matrix, and the implementation of a reconstruction algorithm. Finally, experiments are carried out to investigate the performance of the CS method for on-line CM. Experimental results show that the IGBT turn- off time at different temperatures can be accurately monitored with a highly compressed sampling rate, which validates the feasibility and effectiveness of the proposed method.

&lt;italic&gt;In situ&lt;/italic&gt; Condition Monitoring of IGBTs Based on the Miller Plateau Duration

Aging precursor identification is crucial to achieving online condition monitoring and estimating the remaining lifetime of insulated-gate bipolar transistors (IGBTs). However, existing failure precursors are limited with respect to in situ monitoring. In this paper, the duration of the Miller plateau during the IGBT turn- on transition is proposed as an online precursor indicating two dominant types of failures. Based on the theoretical closed-form expressions, the adverse effects of package-related bond wire fatigue and chip-related gate oxide degradation on the Miller plateau duration are explained. By using a dedicated online measurement system that is implemented on the gate driver side, the proposed precursor is extracted during operation. Discrete IGBTs of two gate structures are employed during the accelerated aging tests. Negative and positive degradation trends of the Miller plateau duration under power cycling and high electric field stress, respectively, are revealed, thus illustrating the validity of the proposed method. Finally, the main differences in physics-of-failure between two types of aged devices are investigated using post-failure analysis. The innovation of applying the Miller plateau duration as a failure precursor involves its ability to accomplish real-time field monitoring and its sensitivity to multiple failure mechanisms.

Demagnetization monitoring and life extending control for permanent magnet-driven traction systems

Abstract This paper presents a novel scheme of demagnetization monitoring and life extending control for traction systems driven by permanent magnet synchronous motors (PMSMs). Firstly, the offline training is carried to evaluate fatigue damage of insulated gate bipolar transistors (IGBTs) under different flux loss based on first-principle modeling. Then an optimal control law can be extracted by turning down the power distribution factor of the demagnetizing PMSM until all damages of IGBTs turn to balance. Next, the similarity-based empirical modeling is employed to online estimate remaining flux of PMSMs, which is used to update the power distribution factor by referring the optimal control law for the health-oriented autonomous control. The proposed strategy can be demonstrated by a case study of traction drive system coupled with dual-PMSMs. Compared with traditional control strategy, the results show that the novel scheme can not only guarantee traction performance but also extend remaining useful life (RUL) of the system after suffering demagnetization fault.

An IGBT Gate Driver for Feed-Forward Control of Turn-on Losses and Reverse Recovery Current

This paper addresses the problem of turn on performances of an insulated gate bipolar transistor (IGBT) that works in hard switching conditions. The IGBT turn on dynamics with an inductive load is described, and corresponding IGBT turn on losses and reverse recovery current of the associated freewheeling diode are analysed. A new IGBT gate driver based on feed-forward control of the gate emitter voltage is presented in the paper. In contrast to the widely used conventional gate drivers, which have no capability for switching dynamics optimisation, the proposed gate driver provides robust and simple control and optimization of the reverse recovery current and turn on losses. The collector current slope and reverse recovery current are controlled by means of the gate emitter voltage control in feed-forward manner. In addition the collector emitter voltage slope is controlled during the voltage falling phase by means of inherent increase of the gate current. Therefore, the collector emitter voltage tail and the total turn on losses are significantly reduced. The proposed gate driver was experimentally verified and compared to a conventional gate driver, and the results are presented and discussed in the paper.

Modeling of IGBT Resistive and Inductive Turn-On Behavior

Although insulated-gate bipolar-transistor (IGBT) turn-on losses can be comparable to turn-off losses, IGBT turn-on has not been as thoroughly studied in the literature. In the present work IGBT turn on under resistive and inductive load conditions is studied in detail through experiments, finite element simulations, and circuit simulations using physics-based semiconductor models. Under resistive load conditions, it is critical to accurately model the conductivity-modulation phenomenon. Under clamped inductive load conditions at turn-on there is strong interaction between the IGBT and the freewheeling diode undergoing reverse recovery. Physics-based IGBT and diode models are used that have been proved accurate in the simulation of IGBT turn-off.