Fast Recovery Diode Research Articles

A pulser R&D for the HEPS booster bumper magnet

The High Energy Photon Source (HEPS) is a fourth generation photon source, including a storage ring, a booster ring and a Linac. Due to the small dynamic aperture of the storage ring, a novel on-axis swap-out injection scheme was chosen. Here, the 6GeV booster acts as an accumulating ring during that injection process. To extract 6 GeV beam from the booster before injection into the storage ring, four slow bumper magnets are applied to assist the extraction kicker to accomplish. The bumper pulse magnetic field waveform is a half-sine wave with 1ms pulse bottom width. Depending on the simulation and test, a classic LC resonance circuit topology with IGBT switching in series with fast recovery diodes is adopted. In addition, an energy recycle circuit and capacitor charging circuit are designed, to decrease power loss and reduce the influence on the output pulse current waveform during the capacitor re-charge process. A pulsed power supply prototype has been completed, and the testing results show that the bumper pulser can fully meet the all requirements of HEPS booster high energy extraction system.

A Solid-State Marx Generator with Prevention of through Current for Rectangular Pulses

In solid-state high-voltage pulse generators, switches may be triggered on by fault due to electromagnetic interference, resulting in high through current and breakdown of switches. To generate rectangular high-voltage pulses, this paper proposes a solid-state Marx generator (SSMG) with fast recovery diodes to prevent through current. Only charging currents with the same direction flow through these fast recovery diodes breaks the short-circuit loops in and between stages. A 52-stage SSMG prototype based on the proposed circuit was developed. PSpice simulations and experiments were performed for comparison. It was found that the through current can rise to 250 A without any protection. With 10-μH protection inductors in each state, the through current amplitude drops to 50 A. Under the same condition, there is no continuous through current with the proposed fast recovery diodes. Furthermore, 22-kV repetitive rectangular pulses were also obtained in experiments. This proved that the proposed Marx generator can prevent the through current in power cells.

Solid-state Marx generator based on saturable pulse transformer and fast recovery diodes

Solid-state compact Marx generator using saturable pulse transformer (SPT) and fast recovery diodes has been proposed. The primary circuit is switched by three MOSFETs connected in parallel. The SPT functions as a step-up transformer to increase the voltage amplitude and as a closing switch for the secondary circuit. Meanwhile, all the SPTs share the same magnetic core to achieve a compact structure and ensure good synchronization. The energy storage capacitors on the secondary sides are charged through the unsaturated SPT. When the SPT saturates, the capacitors firstly transfer a little energy to the saturated inductors through the diodes reversely during their reverse recovery process. Currents rise quickly in these inductors until diodes totally recover to reverse blocking state. Then capacitors discharge in series to the load and high-voltage pulses are generated over the load. With the currents in the saturated inductors, the front edges of pulses are no longer affected by them but are dominated the turn-off speed of the diodes, which makes high-voltage and high-current pulses with short front edges possible. The regular and cheap fast recovery diodes in the generator act as semiconductor opening switch to sharpen the pulse front edges. Experiments were carried out with a 4-stage Marx generator prototype, 10.8-kV high-voltage pulses with a front edge of 11 ns, a pulse width of 190 ns, were obtained over a 100-Ω resistive load. The total energy efficiency is 49.8%. The proposed Marx generator using regular fast recovery diodes is compact, cheap, and efficient to generate high-voltage pulses with short front edges.

Comprehensive Analysis and Experiment of Extreme Faults in MMC Based on IGCT

High voltage direct current voltage source converter (HVDC-VSC) technology is one of most important solutions for transmission of large-scale renewable sources. Modular multilevel converter (MMC) is one of the most popular topologies for HVDC-VSC system. The extreme faults affect the safety and reliability of MMC greatly. This paper gives comprehensive analysis and experiment of extreme faults in MMC based on integrated gate commutated thyristor (IGCT). Causes and characterization of the extreme faults are analyzed in detail. A new protection solution based on IGCT with controlled punch-through design (CP-IGCT) and fast recovery diode with high surge current capability (HS-FRD) is proposed. The surge current capability of HS-FRD is validated via experiment successfully. Theoretical calculation shows that the protection solution based on CP-IGCT and HS-FRD can help reduce the maximum fault current below 50% when the anode inductor is 0.8 μH in the extreme shoot-through fault. Test results show that the protection solution can realize the discharge of the DC capacitor below 4.5 kV in the extreme shoot-through fault. The maximum fault current in MMC based on IGCT is only about 600 kA while the maximum fault current in MMC based on insulated gate bipolar transistor (IGBT) is over 1100 kA. Explosion proof of CP-IGCT is validated during the tests, which is similar to that of the protection thyristor. However, IGBT can't guarantee the stability of the package and may cause severe safety problem. The failed CP-IGCT has the short circuit failure mode (SCFM) and can be used for bypass of the faulty MMC sub-module (MMC-SM). Via comparison, the proposed protection solution has lowest cost and complexity, as well as the highest safety.

Research on Triode Based High Re-Frequency Ultrafast Electrical Pulse Generation Technology

The high-repeat frequency ultrafast electrical pulse generation technology is mainly based on ultrafast switching devices combined with ultrafast circuits to generate electrical pulses with repetition frequencies of several kilohertz and a rise-time of nanoseconds or even picoseconds. This technology is the basis for several research studies and is one of the key technologies that has received wide attention from various countries. The problems to be solved are high re-frequency ultrafast high-voltage pulse generation and ultra-broadband ultrafast pulse transport and circuit stability applicability, which include circuit conduction mechanism research, pulse generation time improvement and recovery time reduction. By studying the avalanche transistor high-voltage transient conduction characteristics and reducing the loss in the carrier transport process, the influence of each parameter on the output is determined, and the key factors to enhance the circuit performance are identified. This paper designs a new high-repetition frequency ultrafast electric pulse generation (UPG) circuit using pure electronics components, which consists of combining avalanche transistor model 2N2222 with a hybrid Marx structure at the same time in the pulse circuit to add filtering, fast recovery diodes and pulse cutoff and other matching techniques to make its output more stable, which can obtain higher output frequency, faster rise-time and narrower pulse widths. It has been tested that a high re-frequency ultrafast high-voltage electrical pulse signal with a pulse repetition frequency of 200 kHz, a leading edge of 800 ps, a half-high pulse width of 5 ns, an amplitude of 1.2 kV and jitter of less than 5% can be generated at the load with a 50 Ω load at the output. The signal can be applied in the fields of ultrafast diagnosis, information countermeasures and nuclear electromagnetic radiation research.

Comprehensive Analysis and Experiments of RB-IGCT, IGCT With Fast Recovery Diode and Standard Recovery Diode in Hybrid Line-Commutated Converter for Commutation Failure Mitigation

Commutation failure is one of the most important factors threatening the safety of multi-infeed high voltage direct current systems. To mitigate commutation failure, we have proposed a novel hybrid line-commutated converter by adding fully controlled devices to the conventional line-commutated converter. It aims to achieve auxiliary commutation and forced commutation with the help of fully controlled devices. Based on the novel hybrid line-commutated converter topology, the study investigates how to select suitable fully controlled devices and how to design the appropriate parameters of the devices. First, this article studied the general characteristics of reverse-blocking devices, including reverse-blocking integrated gate-commutated thyristor (RB-IGCT) and asymmetrical IGCT with diode (including fast recovery diode and standard recovery diode). Then, the novel commutation principle is carefully proposed and analyzed. The comprehensive simulation results and comparison study of the novel commutation principle are conducted. Then, according to the proposed commutation principle, the voltage and current working stress of devices are illustrated. According to these, vital features of devices, including recovery speed, <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -state voltage, current conduction ability, surge current, maximum turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> current, robustness, and volume of devices, are carefully analyzed and compared. Related experiments are conducted to present the vital characteristics of devices in the equivalent operating conditions in converters. Finally, the advantages and disadvantages of RB-IGCT and IGCT with fast recovery diode and standard recovery diode are comprehensively presented, which offers valuable reference considered in engineering applications.

A Fast and Soft Reverse Recovery Diode With a Punch-Through NPN Structure

A fast and soft reverse recovery diode with a Punch-Through (PT) NPN structure is proposed and experimentally demonstrated. The structure features a P-type Schottky contact, a PT-NPN region for electron extraction, and a trench region with the bottom surrounded by a P-layer. Compared with conventional Self-adjusting P Emitter Efficiency Diode (SPEED), the proposed PT-NPN diode provides a much larger softness factor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S}$ </tex-math></inline-formula> (+23%), a shorter reverse recovery time <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T}_{\text {rr}}$ </tex-math></inline-formula> (−5%), and a much reduced reverse recovery charge <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{\text {rr}}$ </tex-math></inline-formula> (−20%) at nominal current.

Study on the Characteristics of FSRD with a Corrugated Anode and p+ Adjustment Region at Cathode

The reverse recovery characteristic of the power diode will directly affect the reliability of the inverter application. In order to improve the reverse recovery characteristics of the fast and soft recovery diode (FSRD), a new FSRD structure with Corrugated Anode and P+ adjusting Cathode (CA-PC-FSRD) is studied by the Sentaurus-TCAD simulator and compared with the characteristics of conventional FSRD. The influence of key parameters, such as the height and width of anode corrugation and the width of the p+ adjusting region at the cathode, on the characteristics are discussed. Simulation results show that the CA-PC-FSRD has excellent soft recovery characteristics compared with the conventional FSRD at the same voltage level.

Application-specific fast-recovery diodes

Application-specific fast-recovery diodes

Fast Recovery Diodes for High-Current High- Voltage Insulated Gate Bipolar Transistors

Silicon Fast Recovery Diodes of 4.5 kV class were produced with diameter of active area between 100 and 150 mm. Wide Safe Operation Area is experimentally demonstrated with IGBT operated at di/dt above 4 kA/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> for which diode recovery losses and peak power show decreasing trend above the diode average rating current of 5 kA, which is half of Insulated Gate Bipolar Transistor (IGBT) short circuit current. The role of IGBT switch and diode design on the robustness enhanced by increased diode area, is explained. The experimental results are confirmed by device simulation (TCAD).

Epoxy Mold Compound Encapsulation Concept for Large-Area Power Devices

A new concept for encapsulation of discrete bipolar high-power devices using epoxy mold compound (EMC) is demonstrated on silicon 4.5-kV press-pack fast recovery diodes (FRDs) with wafer diameter up to 130 mm and molybdenum pressure-release buffer up to 140 mm in diameter. The silicon wafers can be bonded to molybdenum disks using the low-temperature bonding (LTB) process or they can be fixed mechanically by the EMC without direct bonding (free floating). The encapsulated devices can be applied as housing-less or they can be inserted into hermetic ceramic housings with pole piece of 143 mm. The design aspects relevant for reliable operation are presented using multiphysics simulation in COMSOL. The summary of passed reliability tests, including electrical testing in true application conditions, demonstrates readiness of the concept for demanding applications in the temperature range up to 140 &#x00B0;C.

АВТОМАТИЗИРОВАННЫЙ РАСЧЕТ СТАТИЧЕСКИХ ХАРАКТЕРИСТИК КРЕМНИЕВЫХ БЫСТРОВОССТАНАВЛИВАЮЩИХСЯ ДИОДОВ ДЛЯ ПРИМЕНЕНИЯ В УСТРОЙСТВАХ СИЛОВОЙ ЭЛЕКТРОНИКИ

Calculating, analysing and verifying current-voltage characteristics (CVC) of a silicon fast-recovery diode (FRD) are performed using the methods of instrumental-technological modelling. The article determines the planar structure configuration of a semiconductor device crystal, the levels of doping and doses of irradiation with high-energy particles, at which the required values of operating and maximum forward currents and reverse (breakdown) voltages are achieved. The main tasks to be solved in the article are to determine the optimal design and technological parameters of the fast-recovery diode (FRD) structure and verifying the calculated current-voltage characteristics (CVC) values with the experimental data taken from the SKKE310F12 fast recovery diode at various ambient temperatures. The novelty of the work is represented by the obtained verified instrumental-technological model of FRD, which is possible for industrial implementation in the form of a semiconductor device at the production base of domestic microelectronics enterprises. The results of the research can be used in producing the element base of power electronics for pulsed power converters, namely discrete FRD, FRD structures as part of power modules based on MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and IGBT transistors.

Switching-Cell Buck–Boost AC–AC Converter With Common-Ground and Noninverting/Inverting Operations

This article proposes a switching-cell-based bipolar buck-boost ac-ac converter that can provide multiple modes of operation, including noninverting buck operation, noninverting boost operation, inverting buck-boost operation, and adjustable noninverting buck-boost operation with two control duty ratios. Each fundamental switching-cell in the proposed converter is composed of a unidirectional buck circuit with no short-circuit or open-circuit problems, increasing its robustness. Hence, safe commutation is naturally realized without the use of RC snubbers or soft-commutation strategies, removing the need for pulsewidth modulation deadtimes. External fast recovery diodes are utilized, avoiding the high-frequency conduction of MOSFET's body diodes and eliminating their slow reverse recovery problem and corresponding power loss. The proposed converter shares a common ground between input and output ports, offers support for reactive loads, draws continuous sinusoidal current from ac mains, and delivers a continuous output current. The converter is suitable for ac voltage regulation applications, notably as a dynamic voltage restorer, compensating extensive magnitudes of both grid voltage sags and swells. Circuit operation and analysis are provided for all the proposed modes of operation. Experimental results obtained using a 400-W laboratory-scale hardware verify the theoretical analysis.

Single-Phase Photovoltaic Inverters With Common-Ground and Wide Buck–Boost Voltage Operation

The output voltage of a photovoltaic panel is greatly affected by irradiance, temperature, shading, etc. A buck-boost type inverter is, therefore, required to accommodate the wide fluctuations in dc voltage. This article proposes a class of single-phase, single-stage buck-boost inverters employing five switches (implemented using power MOSFETs with external fast recovery diodes) to provide buck-boost operation for wide variations in photovoltaic (PV) output voltage. In this article, the proposed inverters are immune from current shoot-through problems associated with voltage source inverters, easing the requirement for PWM dead-times. They also provide a common-grounding feature between the grid-neutral and the negative-terminal of the PV panel, successfully suppressing the PV leakage current. In addition, they provide reactive power support. A simple input boost inductor-based buck-boost inverter is proposed with a wide gain range; other variants are also proposed based on the switched inductor, quadratic boost, and switched coupled-inductor, achieving higher boost voltage inversions with smaller values of duty ratio. Detailed circuit operations are presented based on proposed modulation strategies. Design guidelines/requirements of components and their comparisons are provided for all of the proposed inverters. The theoretical analysis and performance characteristics of all four topologies are experimentally validated using 400 VA laboratory prototype inverters.

A Phase Change Material Integrated Press Pack Power Module With Enhanced Overcurrent Capability for Grid Support—A Study on FRD

The capability of dynamic grid support of a voltage source converter-high voltage direct current (VSC-HVdc) system depends on the maximum allowable current of the converter. This study attempts to increase the capability by overloading the power semiconductor device for a short period of time. Keeping the device temperature low is a major challenge due to the extra loss and small local thermal capacity. This study investigates a solution to increase the transient thermal capacity by making use of the latent heat of a phase change material (PCM). This article presents an integration scheme for a press pack power module, focusing on the fast recovery diode in an IGBT-diode package. Experiment and finite element analysis are used to evaluate the concept and analyze the factors affecting the design. It is shown that as heat is absorbed by the integrated PCM, the device temperature rise during a power surge is effectively tempered, providing a high short-term overcurrent rating of the device and an increased dynamic grid support capability of the VSC-HVdc system.

A bridgeless CUK PFC converter with positive output voltage

The output voltage of the traditional CUK PFC converter is negative, and an additional inverting amplifier circuit is needed, which increases the volume and cost of the converter. A new type of bridgeless CUK PFC converter topology is proposed in this paper, which makes the converter have a positive output voltage without the need of an additional inverting amplifier circuit, and has the advantages of simple control, high efficiency, and low cost. Through topology optimization, one input capacitor is reduced, and the two diodes are converted from the high-current working state of high frequency to low-current working state of power frequency, ordinary rectifier diodes can be selected instead of fast recovery diodes, thereby reducing the volume and cost of the converter. The converter works in DCM, so no current control loop is required, which simplifies the control circuit. In addition, the main switch is turned on under ZVS condition, and the output diode is turned off under ZCS condition, which reduces the switching loss and improves the efficiency of the converter. A simulation model was built in PSIM, and a prototype with a rated power of 150 W was fabricated to verify the effectiveness and superiority of the proposed converter. Experimental results show that the PF of the proposed converter is 0.995 7, and the input current THD is 3.78% under rated input conditions.

High-Voltage Hybrid IGBT Power Modules for Miniaturization of Rolling Stock Traction Inverters

A type of 3.3-kV/450-A half-bridge insulated-gate bipolar transistor power module combining the silicon (Si) and silicon carbide (SiC) technologies has been developed and reported in this article, for the miniaturization of the Chinese high-speed railway rolling stock traction inverters. This module is developed by integrating the next-generation industrial standard high-voltage packaging topology and the state-of-the-art 3.3 kV wide bandgap semiconductor chip technology, to reduce the waste power dissipation during operation, which in turn can lead to effective downsizing of key components in the traction inverter design. The module layout characteristics and the SiC Schottky barrier diodes design for substitution of the conventional Si fast recovery diodes will be described in detail. The mechanical, thermal, and electrical performances of the hybrid module are compared comprehensively with the Si-based counterpart. Based on the experimental results, an inverter system level evaluation of both modules is also conducted by electro-thermal simulation. The hybrid module shows advantages in loss reduction leading to great potential of system miniaturization, which is a cost effective solution for massive upgrading of the existing high-speed train traction inverters.

A Method for Thermal Resistance Test of Reverse-Conducting IGBT (RC-IGBT)

The RC-IGBT is integrated IGBT and fast recovery diode (FRD) on the same chip. RC-IGBT has smaller size, higher power density, lower cost, and higher reliability. However, due to the snap-back effect, the traditional test circuit and method cannot accurately measure the thermal resistance of RC-IGBT. In this paper, a thermal resistance test circuit based on series compensation of two devices is proposed, and the voltage drop Vec of the body diode is taken as the temperature sensitive parameter of RC-IGBT. The thermal response curve is obtained basing on the change of Vec with temperature. By comparing the traditional method with the new method, it can be seen that the new method can greatly improve the test accuracy.

Current Oscillation Phenomenon of MMC Based on IGCT and Fast Recovery Diode With High Surge Current Capability for HVDC Application

Integrated gate commutated thyristor (IGCT) has low loss, low cost, and high reliability in the application of modular multilevel converter (MMC). However, due to the special turn-off process of IGCT, the commutation transient is very different for IGCT in MMC. This letter reveals a current oscillation phenomenon of MMC based on IGCT and fast recovery diode (FRD). Especially, this oscillation effect becomes apparent when the FRD with high surge current capability is employed in MMC because of high junction capacitance and high stray inductance, which will threaten the safe operation of the system. This letter analyzes the current oscillation mechanism and gives the current oscillation modeling. In addition, through detailed tests under various stray inductances, the specific stray inductance range that can cause large current oscillation is obtained and an optimized inductance parameter of IGCT-MMC is proposed. The experiments show that the safe operation area of IGCT in MMC can be guaranteed maximally with the optimized parameter.

Design and Implementation of Novel Noninverting Buck–Boost AC–AC Converter for DVR Applications

This article proposes the new noninverting buck–boost ac–ac converter, which can minimize the reverse recovery loss by disabling the body diodes of switches and using the external fast recovery diodes for its current freewheeling. In particular, the proposed ac–ac converter takes advantages of metal-oxide semiconductor field effect transistors and external fast recovery diodes to achieve the high efficiency. Also, it has the high reliability without the shoot-through and dead-time considerations in the circuit. Moreover, it can be simply implemented without employing the conventional commutation control. This results in decreasing the control complexity. As its proper application, a new type of dynamic voltage restorer (DVR) based on the proposed noninverting buck–boost converter is described. It enables to solve the voltage sag and swell problems by utilizing both positive and negative gains of converter. Then, the hardware prototype of proposed ac–ac converter and DVR are implemented to verify their practical effectiveness.