Multiple Insulated Gate Bipolar Transistors Research Articles

A current sharing snubber of parallel IGBTs based on duality principle

Parallel connection of multiple insulated gate bipolar transistors (IGBTs) is an important approach to improve the current level of equipment in applications of power electronics. The key to ensure the safe and stable operation of parallel IGBTs is to realize current sharing for them. A novel current sharing snubber of parallel IGBTs is proposed for high-power applications, which is derived from a voltage sharing snubber of series IGBTs by duality principle. It not only effectively suppresses the overcurrent and static and dynamic current imbalance, but also possesses advantages of simple structure and easy implementation. The operating principle and deficiencies of the proposed snubber are first analyzed, and then the improved topology is presented. In order to apply the snubber to multiple IGBTs, various topologies and their derivation processes are given. The improvements are carried out and suitable structures are determined by analysis and comparison. In addition, the effectiveness and feasibility of the proposed snubber are verified by experiments. Finally, the proposed snubber is compared with other current sharing methods.

초고속차단기와 바이패스 사이리스터를 이용한 MMC의 DC-Link 고장전류 차단 방법

The modular multi-level converter (MMC) has recently gotten great attention due to the installation of large renewable generation farms and high voltage direct current transmission (HVDC). In the same manner as the conventional inverters, MMC operates based on multiple insulated-gate bipolar transistors (IGBTs). Each IGBT is generally combined with an anti-parallel diode in the half-bridge MMC, the most efficient MMC topology. Due to the diode path, the DC fault current, caused by the AC phase voltage differences when its DC-Link bus shorts, flows the MMC freely. This paper proposes a DC-Link fault current interrupting method based on Ultra Fast Disconnectors (UFDs) and bypass thyristor. The proposed method is verified based on electromagnetic transient (EMT) level simulations, including several case studies with various short circuit ratios (SCRs) and reluctance per resistance (X/R) ratios. As a result, the proposed method successfully blocks the DC-Link fault current within at most one cycle. The case studies are conducted using a power system computer aided design and electromagnetic transient including DC (PSCAD/EMTDCTM).

Open-circuit faults diagnosis and Fault-Tolerant Control scheme based on Sliding-Mode Observer for DFIG back-to-back converters: Wind turbine applications

One of the most common types of wind turbines is the Doubly-Fed Induction Generator with a back-to-back converter. The Insulated Gate Bipolar Transistor switch’s open-circuit fault rate compared to the fault total rate in the wind turbine is noteworthy. The converter Insulated Gate Bipolar Transistor open-circuit causes a drawback in output current and as a result, the production performance of the turbine is reduced. In this article, a new method is presented for multiple Insulated Gate Bipolar Transistor open-circuit faults for open-circuit faults diagnosis. After the fault occurs, to maintain the performance of the turbine, fault compensation is performed based on the new Fault-Tolerant Control scheme. The proposed method is inexpensive, and for fault detection and location determining no need for additional sensors and hardware. This method uses residual output based on the Sliding Mode Observer with SAT function to detect faulty phase and overcome chattering Doubly-Fed Induction Generator converter. To residual evaluate and reduce the false alarm rate against changes in operating points and transient currents, the adaptive threshold is used. For efficient control of active or reactive power and dc-link voltage, a six-leg converter control based on Simplified Space Pulse Width Modulation is replaced by a five-leg converter based on Space Vector Modulation. Several experimental results using hardware in the loop Doubly-Fed Induction Generator test setup with a back-to-back converter are presented. It is shown the fault diagnostic algorithm is effective and robust against false alarms for both rotor and stator-side converters. The experimental result presents that the Fault Tolerant Control scheme can make power switch fault easily managed by the hardware reconfiguration and new control strategy adjusting.

An RLL Current Sharing Snubber for Multiple Parallel IGBTs in High Power Applications

A resistor–inductor–inductor <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(RLL)</i> snubber is proposed for high-power power electronic devices that use insulated gate bipolar transistors (IGBTs) in parallel. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLL</i> snubber provides current sharing for parallel IGBTs by utilizing series inductors to decrease the rate of current change in turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> and turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> transients. Compared with other methods, the proposed snubber incorporates only passive components without additional sensors or control circuits, which shows its advantages of simple structure, strong applicability, and easy implementation. In order to further expand its application scope, the topologies of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLL</i> snubber for multiple IGBTs in parallel are designed and improved. Experimental results of 5 and 6 parallel IGBTs validate the feasibility and effectiveness of the proposed snubber.

OC fault diagnosis of multilevel inverter using SVM technique and detection algorithm

The Open Circuit (OC) faults occurring in switches of Multilevel Converters (MLC) may lead to undesirable operation of the converter. Therefore, fault detection and its localization in minimum time are necessary. This paper focuses on the fast fault detection algorithm based on the two samples technique and the fault localization algorithm using the Entropy of Wavelet Packets (EWP) as a feature. The EWP feature is used to classify and localize the OC faults in Insulated Gate Bipolar Transistors (IGBTs) of three-phase, three-level inverter using Support Vector Machine (SVM) based fault classification algorithm. The proposed technique can detect the fault in single IGBT and multiple IGBTs in a lesser time range of microseconds to 0.33 ms. It gives better performance and accuracy (99.70%) than previously proposed SVM algorithms, as the EWP-based feature extraction process used in this paper is simple and accurate with a less computational burden.

A bio-inspired, low pressure drop liquid cooling system for high-power IGBT modules for EV/HEV applications

Abstract Thermal management of high power density insulated gate bipolar transistors (IGBTs) using a low pumping power is crucial for the development of high-performance electric vehicles (EVs) and hybrid electric vehicles (HEVs). In the present work, the liquid cooling module inspired by a human respiratory system was developed to provide enhanced thermohydraulic performance. The suggested cooling module consists of a multiscale flow manifold connected to a metal foam layer bonded to the bottom substrate of IGBT module. The unique flow path uniformly distributes the coolant to multiple IGBTs with minimizing the required pumping power, while maximizing the heat exchange area. The porosity of the metal foam was determined considering the conflict between the conductive and convective heat flux. The developed cooling module was applied to the single IGBT module, including 6 IGBT/diode pairs generating 1.55 kW of heat. The proposed cooling module provided a low (0.2 K/W) thermal resistance using only ~2 kPa of the pressure drop that is approximately 10 and 100 times lower than that of previously reported turbulator and microchannel systems, respectively. Even when the number of IGBT/diode pairs is increased from 6 to 24 (single to quadruple IGBT modules), only ~8 kPa of the pressure drop was required, which shows the high scalability of the proposed solution. This work will help develop a compact, low pumping power cooling solution for high-performance EV/HEV applications.

Long‐distance wireless power transfer system powering multiple loads with constant voltage outputs using S‐SP compensation

This paper proposes a long-distance multi-load wireless power transfer (WPT) system with a constant voltage (CV) output for each load. A repeater unit consisting of two bipolar repeater coils is designed to power the load. Multiple repeater units are placed in a line and the power can be transferred from one unit to the next. Each repeater unit corresponds to one load and multiple loads can be powered simultaneously. The two repeater coils in the same repeater unit are placed perpendicularly to eliminate the magnetic coupling between them. In each repeater unit, a compensation capacitor is placed in series with the transmitting coil while two extra compensation capacitors form a series-parallel (SP) structure for the receiving coil. When neglecting the coil's parasitic resistance, the CV characteristics can be obtained, which enables the independent and flexible power control of each load. Moreover, the influence of the parasitic resistances on the system performance is analysed. Such a system is especially suitable for powering the gate drivers in a high-voltage converter where multiple insulated gate bipolar transistors (IGBTs) are connected in series. An experimental setup with six loads is constructed to validate the proposed system. The maximum system efficiency can reach 88.1%.

A Diagnosis Strategy for Multiple IGBT Open-Circuit Faults of Modular Multilevel Converters

Multiple insulated gate bipolar transistor (IGBT) open-circuit faults severely affect the reliable operation of modular multilevel converters (MMCs). The existing literatures have not provided an effective diagnosis algorithm for MMCs when multiple IGBT open-circuit faults simultaneously appear in one arm. This article presents a diagnosis strategy to handle that condition. Fault detection and estimation of the faulty submodule (SM) number is implemented by checking the value of the arm voltage error. The faulty SMs are located by observing when the transition of their switching functions leads to an obvious change of the arm voltage error. Meanwhile, the errors between the measured and predicted capacitor voltages are utilized to accelerate the localization. All of the faulty SMs can be quickly located one by one within several control cycles by using the proposed localization method. Simulation and experimental results demonstrate the validity of the proposed diagnosis strategy.

An Online Data-Driven Method for Simultaneous Diagnosis of IGBT and Current Sensor Fault of Three-Phase PWM Inverter in Induction Motor Drives

This article presents an online data-driven diagnosis method for multiple insulated gate bipolar transistors (IGBTs) open-circuit faults and current sensor faults in the three-phase pulsewidth modulation inverter. The fast Fourier transform (FFT) algorithm is used to extract the fault frequency spectrum features of the three-phase currents. Then, a feature selection method named ReliefF is introduced to select the most critical features by removing redundant and irrelevant features. In addition, as novel fast learning technology, a random vector functional link network is applied to learn the faulty knowledge from the historical dataset. Based on the well-learned model, the fault type and location of the converter can be accurately identified as long as the three-phase current signals are measured. Offline test results verify that the proposed method can identify the IGBT and sensor faults with an accuracy of 98.83% and outperforms the state-of-the-art learning algorithms. Moreover, the real-time hardware-in-the-loop test results show that the proposed method can successfully identify the IGBT faults and current sensor faults within 22 ms. It is robust to the dc-link voltage fluctuations, model parameters, and speed or load variations. The extensibility of the proposed method is also validated based on the test results in terms of other fault modes and drive systems.

Model Predictive Direct Duty-Cycle Control for PMSM Drive Systems With Variable Control Set

Finite control set model predictive control has received extensive attention because of its excellent dynamic performance; however, it still needs to be studied in terms of torque ripples reduction and parameter robustness. To reduce the steady-state torque ripples and maintain the appropriate antiparameter perturbation ability, in this article, we propose a model predictive direct duty-cycle control (MPD2C) strategy based on “variable control set (VCS).” In the proposed strategy, the direct mapping relations between the electromagnetic torque, flux, and three-phase duty cycles have been established by exploring the dual relationship of vector synthesis and duty cycles. On this basis, the novel predictive model and VCS that uses the three-phase duty cycles as the key variable are constructed. Finally, the proposed strategy determines the three-phase duty cycles from VCS by employing a two-stage optimization mechanism, which means the proposed strategy can generate virtual vectors with multiple insulated gate bipolar transistor (IGBT) switching patterns. Then, the high-precision torque and flux adjustment would be achieved. The experimental results show that VCS-MPD2C has excellent static and dynamic control performance, acceptable execution efficiency, and relatively good parameter robustness.

A Single Method for Multiple IGBT, Current, and Speed Sensor Faults Diagnosis in Regenerative PMSM Drives

This paper proposes a single fault diagnostic method for regenerative permanent magnet synchronous machine drives with the ability to handle multiple insulated gate bipolar transistor faults, single current sensor fault, and rotor-position disconnection. The considered faults are discriminated, and the faulty device is correctly identified in each case. The robustness against false alarms is improved by using adaptive thresholds and normalized diagnostic variables. The proposed algorithm requires the information given by current sensors and the rotor position sensor that are already available from the drive system, without requiring a high computational burden. Simulation and experimental results are presented to validate the effectiveness of the considered algorithm for both motoring and regenerative operations.

A novel series switch module in high-voltage applications

The Tokamak power system requires a high-voltage fast switch because of safety and reliability concerns. This switch can cut off a high-voltage power supply within a short time (usually in microseconds) during faults and system tests. Insulated gate bipolar transistors (IGBTs) satisfy the fast-response requirement of the switch. Directly connecting multiple IGBTs in series is an essential procedure in high-voltage applications. However, voltage balance among IGBTs connected in series is very complex and difficult. No satisfactory method for addressing this issue is currently available. This paper presents a novel switch-circuit module that can operate easily as a modular-connecting high-voltage switch. The topology of the improved modular multilevel converter shows that the switch time is shorter and voltage adjustability is more advanced, respectively, than other switches. The module inhibits overvoltage when it is turned off, which occurs with increased voltage to a rated value by using a high-capacity capacitor. Two IGBTs in overvoltage module are turned on to balance the voltage when the switch is in conducting state. The operated mode increases the current-carrying capacity. A detailed analysis of the submodule is described in this paper. The test prototype is a 4 kV/50 A switch. Results show the excellent performance of the proposed submodule.

Detection and identification of multiple IGBT open‐circuit faults in PWM inverters for AC machine drives

This study proposes a new scheme for online detection and identification of single and multiple insulated-gate bipolar transistor (IGBT) open-circuit faults in three-phase pulse-width modulation (PWM) inverters of AC machine drives, which is based on Park's vector of machine phase currents. First, the switch open-circuit faults are detected by monitoring dwell times of the vector of the actual phase currents expressed in the stationary reference frame in each sector, where the normalisation of the current to its reference value is utilised, by which the immunity to the false alarms in transient conditions is improved significantly. Then, the IGBT open-circuit faults are identified, where leg open-circuit conditions are in the first place determined based on the average values of the normalised line-to-line currents. Next, the single open-circuit IGBT is located from the polarity of the corresponding phase current. By the proposed diagnosis method, the fault detection time is at the longest about 52.3 and 54% of a fundamental period in the simulation and experimental tests, respectively, and the 27 possible cases of IGBT open-circuit faults combined for all IGBTs in the inverter can be identified. In addition, this algorithm can be implemented without any additional hardware and computational burden.

Performance investigation of an advanced diagnostic method for SSTPI-fed IM drives under single and multiple open IGBT faults

PurposeThis paper aims to analyze and investigate the performance of an improved fault detection and identification (FDI) method based on multiple criteria, applied to six-switch three-phase inverter (SSTPI)-fed induction motor (IM) drives under both single and multiple open insulated-gate bipolar transistors(IGBT) faults.Design/methodology/approachThis paper proposes an advanced diagnostic method for both single and multiple open IGBT faults dedicated to SSTPI-fed IM drives considering five distinct faulty operating conditions as follows: a single IGBT open-circuit fault, a single-phase open-circuit fault, a non-crossed double fault in two different legs, a crossed double fault in two different legs and a three-IGBT open-circuit fault. This is achieved because of the introduction of a new diagnosis variable provided using the information of the slope of the current vector in (α-β) frame. The proposed FDI method is based on the synthesis and the analysis, under both healthy and faulty operations, of the behaviors of the introduced diagnosis variable, the three motor phase currents and their normalized average values. Doing so, the developed FDI method allows a best compromise of fast detection and precision localization of IGBT open-circuit fault of the inverter.FindingsSimulation works, carried out considering the implementation of the direct rotor flux oriented control in an IM fed by the conventional SSTPI, have proved the high performance of the advanced FDI method in terms of fast fault detection associated with a high robustness against false alarms, against speed and load torque fast variations and against the oscillations of the DC-bus voltage in the case of both healthy and faulty operations.Research limitations/implicationsThis work should be extended considering the validation of the obtained simulation results through experiments.Originality/valueDifferent from other FDI methods, which suffer from a low diagnostic effectiveness for low load levels and false alarms during transient operation, this method offers the potentialities to overcome these drawbacks because of the introduction of the new diagnosis variable. This latter, combined with the information provided from the three motor phase currents and their normalized average values allow a more efficient detection and identification of IGBT open-circuit fault.

Fault Diagnosis and Fault Tolerant Control of a Three-Phase VSI Supplying Sensorless Speed Controlled Induction Motor Drive

Fault diagnosis in variable speed drives under inverter faults has been widely addressed in the literature. However, research activities in this field have been always focused only on sensored motor drives. This paper deals with a mixed model-based and signal-based approach for both insulated-gate bipolar transistor (IGBT) open-circuit fault diagnosis and fault tolerant control in sensorless speed-controlled induction motor (IM) drive. Sliding mode observer (SMO) is used for speed and stator currents estimation and simultaneously open-switch fault diagnosis. Unlike the classical sensored drive systems, this structure presents particular dynamics under faulty operation-mode which can be taken into account for fault detection and identification (FDI) process designing. The proposed diagnostic algorithm is based on similarity test between measured and estimated currents to define the FDI index in the inverter. The proposed method allows detection and localization of single and multiple IGBT open-switch faults. To improve the reliability of the motor drive, the ability of the SMO to reconstitute the motor state estimation after the disturbance stage of the FTC application is verified. The proposed FDI and FTC schemes are implemented on a dSPACE DS1104 controller board for a 3-kW IM drive system. Several experiments are displayed to show the effectiveness and feasibility of the proposed method.

A New Diagnostic Algorithm for Multiple IGBTs Open Circuit Faults by the Phase Currents for Power Inverter in Electric Vehicles

In order to simplify the application and improve diagnostic speed of the diagnostics, a novel method to diagnose multiple open circuit faults in insulated gate bipolar transistors (IGBTs) by three-phase currents for power inverter in electric vehicles is presented. The summation of currents with semi-period phase-difference is described in diagnostic variables with exploration of the current information in faulty condition. In contrast with plentiful existing methods which rely on the motor models and control parameters, this algorithm merely requires phase currents. Meanwhile, the normalized way based on the absolute phase currents and variable parameter moving average method are applied to improve the diagnostic speed and independence of load variation, which contributes to the real-time application in the electric vehicles. Experimental results, using a vector-controlled permanent magnet synchronous motor (PMSM) and digital signal processor MC56F8346, are presented to verify the algorithm effectiveness, showing many features, such as applicability for multiple open circuit faults, well-robustness against false alarms, briefness and agility for the diagnosis function.

Press-pack IGBTs for HVDC and FACTs

The popularity of insulated gate bipolar transistors (IGBTs) for use in high-voltage direct current (HVDC) transmission and flexible AC transmission systems (FACTS) is increasing. Unfortunately, for these applications wire-bond IGBT technology has a number of shortcomings, such as insufficient current ratings for the most powerful schemes, and inability to fail to short-circuit. Press-pack IGBT technology, conversely, offers increased current ratings, and an inherent short-circuit failure mode, making it a more attractive choice for HVDC and FACTS. However, the design and manufacture of these devices requires a comprehensive understanding of the unique technical challenges, which differ markedly from those for wirebond modules or traditional pressure contact devices. Specific challenges include providing a high degree of mechanical protection for the IGBT chip against normal operating stresses. Furthermore, it is essential to achieve uniform contact pressure across each chip surface to ensure optimum performance. To achieve this, manufacturers have designed products that use rigid copper electrodes manufactured to tighter tolerances than for other pressure contact devices, such as thyristors, and products that use compliant electrodes, incorporating spring assemblies. Dynex is in the advanced stages of development of press-pack IGBT technology with demonstrated robust solutions for the technical challenges outlined in this paper. Design success has been achieved through the use of state-of-the-art simulations in conjunction with a long history of manufacturing expertise for bipolar and IGBT products. Finally, multiple press-pack IGBT variants are currently undergoing evaluation tests prior to product release.

A Robust Observer-Based Method for IGBTs and Current Sensors Fault Diagnosis in Voltage-Source Inverters of PMSM Drives

Permanent magnet synchronous motors (PMSMs) drives using three-phase voltage-source inverters (VSIs) are currently used in many industrial applications. The reliability of VSIs is one of the most important factors to improve the reliability and availability levels of the drive. Accordingly, this paper presents a robust fault diagnostic method for multiple insulated gate bipolar transistors (IGBTs) open-circuit faults and current sensor faults in three-phase PMSM drives. The proposed observer-based algorithm relies on an adaptive threshold for fault diagnosis. Current sensor and open-circuit faults can be distinguished and the faulty sensors and/or power semiconductors are effectively isolated. The proposed technique is robust to machine parameters and load variations. Several simulation and experimental results using a vector-controlled PMSM drive are presented, showing the diagnostic algorithm robustness against false alarms and its effectiveness in both IGBTs and current sensors fault diagnosis.

Thermal Analysis of Cold Plate for Motor Controller Based on Fluent

Electronics cooling research has been largely focused on high heat flux removal from computer chips in the recent years. However, the equally important field of high-power electronic devices has been experiencing a major paradigm shift from air cooling to liquid cooling over the last decade. For example, multiple insulated-gate bipolar transistors (IGBT) used in a power drive for motor used in electric vehicle. Motor drive system plays an important impact on electric vehicle’ performance, so thermal design should be considered in the early stages during the motor controller design and layout of the devices. In this paper, a new type of water-cooled cold plate for motor controller was designed, and its cooling ability was analyzed by using different material base on Fluent. The results provide reference on the optimization design of cold plate.

Solid-state high voltage modulator and its application to rf source high voltage power supplies

A solid-state high voltage modulator is described in which series-connected insulated-gate bipolar transistors (IGBTs) are switched at a fixed frequency by a pulse width modulation (PWM) regulator, that adjusts the pulse width to control the voltage out of an inductor–capacitor filter network. General Atomics proposed the HV power supply (HVPS) topology of multiple IGBT modulators connected to a common HVdc source for the large number of 1 MW klystrons in the linear accelerator of the Accelerator Production of Tritium project. The switching of 24 IGBTs to obtain 20 kVdc at 20 A for short pulses was successfully demonstrated. This effort was incorporated into the design of a −70 kV, 80 A, IGBT modulator, and in a short-pulse test 12 IGBTs regulated −5 kV at 50 A under PWM control. These two tests confirm the practicality of solid-state IGBT modulators to regulate high voltage at reasonable currents. Tokamaks such as ITER require large rf heating and current drive systems with multiple rf sources. A HVPS topology is presented that readily adapts to the three rf heating systems on ITER. To take advantage of the known economy of scale for power conversion equipment, a single HVdc source feeds multiple rf sources. The large power conversion equipment, which is located outside, converts the incoming utility line voltage directly to the HVdc needed for the class of rf sources connected to it, to further reduce cost. The HVdc feeds a set of IGBT modulators, one for each rf source, to independently control the voltage applied to each source, maximizing operational flexibility. Only the modulators are indoors, close to the rf sources, minimizing the use of costly near-tokamak floor space.