Gate Driver Units Research Articles

Low Inductive Characterization of Fast-Switching SiC MOSFETs and Active Gate Driver Units

Accurate switching device characterization is necessary for effectively utilizing the technological ad-vantages of Silicon Carbide (SiC) Power Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) over their Silicon (Si) Insulated-Gate Bipolar Transistor (IGBT) counterparts. With switching times of few nanoseconds, the unprecedented switching speed of SiC semiconductor devices challenges today's converter and characterization setup designs in regard to parasitic layout inductances for optimal conversion and reliable characterization data. Fur-thermore, active gate driving is a key to unlock the potential of SiC MOSFETs, but requires performance assessment prior to integration. This paper presents a low-inductive test platform for flexible and high-accuracy characterization of fast-switching SiC MOSFETs and active gate drivers evalu-ation. The test circuit delivers high quality characterization data that is comparable with a commercial dynamic power device characterizer. In addition to the conventional hard-switching double-pulse tests with a two-level voltage source gate driver, the test circuit offers soft-switching and gate driver evaluation capability in addition. This test platform is a valuable tool for obtaining reliable characterization data to develop more accurate SiC MOSFET simulation models, and evaluate the combination of gate driver and MOSFET prior to the prototyping phase of a converter.

A Novel Detachable Gate Driver Unit With Ultralow Inductance for Integrated Gate Commutated Thyristor

Under the background of clean energy connected to the grid, the high-capacity power electronics device integrated gate commutated thyristor (IGCT) has a bright future. In order to increase the convenience of replacement and longevity of service, a novel detachable gate driver unit (DGDU) concept for IGCT is proposed in this letter. To ensure the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> capability, both connection scheme and board optimization on DGDU are applied to minimize the stray inductance. Besides, the effects because of the detachable connecter on the structure and thermal characteristics are analyzed. Afterward, an overlapping scheme of DGDU with ultralow inductance is proposed for IGCT. Finally, a 4-inch prototype and a single-phase full-bridge platform are developed for the test. The turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> capability of DGDU is verified by pulse experiment, which could turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> a 5 kA current successfully. The stray inductance of DGDU is calculated based on the experimental result and is only 4% larger than conventional GDU, which means the commutation capability has little decrease. Furthermore, the continuous running reliability is verified by 2200 V-dc-voltage, 1300 A-effective-current power cycling experiments.

An Advanced 4-in Integrated Emitter Turn-off Thyristor With Ultralow Commutation Impedance to Achieve 8 kA Turn-off Capability: Comprehensive Analysis, Design, and Experiments

Compared with integrated gate commutated thyristors (GCTs), an integrated emitter turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> thyristor (IETO) has a potential of higher turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> current capability and requires lower power consumption for gate driver units, which is more suitable for high-power applications. Thus, in this article, an advanced design of 4-in IETO was presented. To reduce the gate commutation impedance and enhance the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> current, the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> circuit with low impedance DirectFETs was integrated into the housing. And the housing structure was carefully designed to provide a compact current commutation path. Then, a 4-in IETO prototype based on a 4.5 kV/5 kA GCT wafer was developed. Experimental results show that its maximum turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> current was over 8.1 kA with an extremely short commutation time of 130 ns. And the total commutation inductance was only 0.38 nH. Additionally, the thermal and mechanical characteristics of the housing were also taken into consideration during design and verified by the thermal simulation and mechanical stress test. Consequently, according to this article, IETO has the potential to be a competitive device in high-power applications in the near future.

The Diode-Assisted Gate-Commutated Thyristor—Operation, Design, and Testing

This article presents the diode-assisted gate-commutated thyristor (DAGCT), a power electronic device designed and optimized for hybrid dc circuit-breaker applications employing a fast mechanical circuit breaker. Detailed topology and operation of the DAGCT are illustrated in this article. A package and a gate drive unit (GDU) were developed. The device and the GDU were tested for a fault current of 550 A. The device turned off within ${3.2} ~{\mu }\text{s}$ . The performance of the DAGCT-GDU is compared with other GDUs of similar thyristor-based devices. Test setup and test results are presented and discussed.

Stray Impedance Measurement and Improvement of High-Power IGCT Gate Driver Units

Turn-off capability of integrated gate-commutated thyristor is highly dependent on the commutation capability of its gate driver unit (GDU). To enhance it, stray impedance is the crucial limitation, which has not been obtained accurately before. Thus, in this paper, acquisition method of impedance based on experimental measurements was carefully analyzed, including electrolytic and ceramic capacitors, mosfets, printed circuit board, and GCT housing. And each part of stray impedance was obtained based on a series of experiments with 6-inch GCTs and two types of conventional GDUs. To further enhance commutation speed, an improved GDU was developed, reducing the total stray inductance from 0.395 to 0.037 nH, stray resistance from 0.444 to 0.227 mΩ. An extremely high current of 12.5 kA was successfully turned off, which is the maximum turn-off current level so far. Besides, the maximum commutation capability was tested as over 17 kA. Consequently, no further optimization of GDU is necessary. However, there was still about 1.0 nH existing inside the GCT housing we used. A novel housing with lower stray inductance is expected for higher commutation speed in the future.

Investigation on three‐phase seven‐level cascaded DC‐link converter using carrier level shifted modulation schemes for solar PV system applications

Three-phase seven-level cascaded DC-link converter (CDCLC) is proposed for solar photovoltaic (PV) applications. The proposed configuration is integrated with stepped DC-link module (DCLM) and H-bridge inverter. In CDCLC configuration, the stepped DC-link voltage is attained through DCLMs with reduced inverter voltage stress. Compared with conventional two-level and three-level inverters, power spectral density in the multiples of switching frequency is significantly reduced. Elimination of inverter end filter components emphasises the advantage of CDCLC systems over conventional inverters. A reduction in DC sources, power switches, and gate driver units make the system more cost-effective over conventional cascaded multilevel inverter. To achieve the quality of power output in the proposed converter, carrier level shifted pulse width modulation (CLSPWM) schemes are developed for the DC-link converter switching. Simulated and experimental models of three-phase seven-level CDCLC configuration are developed and its performance is analysed for CLSPWM switching schemes.

철도차량용 IGBT Gate Driver Unit 기술 동향 분석 연구

철도차량용 전원창치는 추진제어용 전원장치와 보조전원장치로 구분된다. 추진제어용 전원장치는 철도차량의 추진 및 회생제동 등의 동작을 위한 것이며, 보조전원장치는 추진제어용 전원을 제외한 공기압축기, 조명기기, 차량제어전원 등의 보조전원에 사용되는 것이다. 각 전원장치는 고전압, 고전류 사양 특성에 따라 일반적으로 insulated-gate bipolar transistor (IGBT)를 스위칭 소자로 사용하고 있다. 스위칭 소자를 사용하기 위해서는 적절한 스위칭 동작을 구현하기 위한 구동회로(Gate Driver Unit, GDU)가 필수적이다. 본 논문에서는 철도차량에 적용되고 있는 IGBT용 GDU에 적용되고 있는 기술 동향을 분석하고 철도차량용 IGBT GDU 설계 시 고려사항에 대해 알아보고자 한다. Power supply for railway cars can be divided into propulsion system power supply and auxiliary power units (APU). The propulsion system power supply is for propulsion of railway cars, and regenerative braking; the APU provides power for the air compressor, lighting, car control and other auxiliary parts. According to high voltage and high current specifications, generally, an insulated-gate bipolar transistor (IGBT) is adopted for the switching component. For appropriate switching operation, a gate driver unit (GDU) is essentially required. In this paper, the technical trends of GDU for railway cars are analyzed and a design consideration for IGBT GDU is described.

Giant Magneto-Impedance Sensor for Gate Driver-Insulated Signal Transmission Functions

A proof-of-concept of the use of a giant-magneto-impedance (GMI) sensor for the realization of signal transmission under high isolation voltage is presented. This technology, which has never been used for gate driver units before, can potentially provide low coupling capacitance (<;1 pF) and high insulation voltage capability up to 40 kV for a gap of 1 mm. The signal information is carried by a magnetic field emitted by a specially designed magnetic coil. The receiver acquires datum thanks to a dedicated high sensitivity and large bandwidth GMI sensor. The technique ensures a high galvanic isolation and provides potentially fast transmission rates while maintaining a low coupling capacitance between the transmitter and the receiver. The aim of this new technology would be to proceed well beyond the performances of coil-coil transmitters. This letter deals with the principles of implementation of this new technique. A prototype has been designed, developed, and tested. First results are given with a discussion about the potential performance and strategies of improvements.

Single-phase Multilevel Inverter with Simpler Basic Unit Cells for Photovoltaic Power Generation

This paper presents a single-phase multilevel inverter (MLI) with simpler basic unit cells. The proposed MLI is able to operate in two modes, i.e. charge mode to charge the batteries, and inverter mode to supply AC power to load, and therefore, it is inherently suitable for photovoltaic (PV) power generation applications. The proposed MLI requires lower number of power MOSFETs and gate driver units, which will translate into higher cost saving and better system reliability. The power MOSFETs in the basic unit cells and H-bridge module are switched at near fundamental frequency, i.e. 100 Hz and 50 Hz, respectively, resulting in lower switching losses. For low total harmonic distortion (THD) operation, a deep scanning method is employed to calculate the switching angles of the MLI. The lowest THD obtained is 8.91% at modulation index of 0.82. The performance of the proposed MLI (9-level) has been simulated and evaluated experimentally. The simulation and experimental results are in good agreement and this confirms that the proposed MLI is able to produce an AC output voltage with low THD.

전동차 인버터 구동용 전해콘덴서의 신뢰도예측과 수명 연구

Inverter module, which feeds the converted power to the traction motor for EMU. Consists of the power semiconductors with their gate drive unit(GDU)s and the control computer for driving, voltage, current and speed controls. Electrolytic condenser, connected to the gate drive unit and a core component to drive the power semiconductor, has problems such as reduction in lifetime and malfunction caused by electrical and mechanical characteristic changes from heat generation during high speed switching for generation of stable power. In this study, To check the service life of electrolytic condenser, the test was carried out in two ways. First, In the case of accelerated life testing of condenser, the Arrhenius model is a way of life testing. Another way is to analyze the reliability of the failure data by the method of parametric data analysis. Eventually, life time by accelerated life test than a method of failure data analysis(Weibull distribution) was found to be slightly larger output.

Dual-Function Gate Driver for a Power Module With SiC Junction Field-Effect Transistors

Silicon Carbide high-power modules populated with several parallel-connected junction field-effect transistors must be driven properly. Parasitic elements could act as drawbacks in order to achieve fast and oscillation-free switching performance, which are the main goals. These two requirements are related closely to the design of the gate-drive unit, and they must be kept under certain limits when high efficiencies are targeted. This paper deeply investigates several versions of gate-drive units and proposes a dual-function gate-drive unit which is able to switch the module with an acceptable speed without letting the current suffer from significant oscillations. It is experimentally shown that turn-on and turn-off switching times of approximately 130 and 185 ns respectively can be reached, while the magnitude of the current oscillations is kept at an adequate level. Moreover, using the proposed gate driver an efficiency of approximately 99.7% is expected for a three-phase converter rated at 125 kVA and having a switching frequency of 2 kHz.

The Integrated Emitter Turn-Off Thyristor (IETO)—An Innovative Thyristor-Based High Power Semiconductor Device Using MOS Assisted Turn-Off

This paper focuses on a new realization method of an emitter turn-off thyristor (ETO). The low-inductive requirements for the unity gain turn-off capability of a gate commutated thyristor (GCT) led to bulky driver stages directly attached to the device. This, combined with the need for electrolytic capacitors, inherently leads to mechanical and thermal design problems, which significantly limit the application opportunities, as well as the device's lifetime and reliability. The concept of the ETO overcomes the need for a capacitor bank by using MOSFETs in the cathode current path of the thyristor. The thermal limitations of the gate driver unit are attenuated by this concept, its bulky lay-out is not. The approach presented in this paper overcomes some drawbacks of the known ETO by integrating the MOSFETs into the press pack. Hereby, a significantly smaller and less complex driver design is achieved.

Thyristor stack for pulsed inductive plasma generation

A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 micros and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/micros.