Reverse Recovery Current Research Articles

다상 DC-DC 컨버터의 입력 전류 리플 저감 제어 알고리즘

Input current ripple and harmonic components of the power device are main causes of electromagnetic interference (EMI). Although the discontinuous conduction mode (DCM) operation can reduce harmonic components of the power device by reducing reverse recovery current of diode and turn-off voltage spikes of the switch, input current ripple increases due to high peak to peak inductor current. Therefore, in this paper, frequency control algorithm is proposed to reduce the input current ripple of DCM operated interleaved boost converter. In the proposed algorithm, duty ratio is fixed either 0.33 or 0.67 to minimize the input current ripple and the switching frequency is controlled according to operating conditions. 600 W 3-phase interleaved boost converter prototype system is built to verify proposed algorithm.

Research on Commutating Over-Voltage Protection for High Power Converter

In the course of converter normal operation, large transient surges called commutating over-voltage may be generated internally during the commutating process of thyristor. The commutating voltage can effectively be reduced by the RC snubber circuit parallel to thyristor. In the RC snubber circuit design of high power thyristor, the reverse recovery process of thyristor must be considered in detail. Based on the analysis about reverse recovery transient of thyristor, the mathematical model of the converter thyristor reverse recovery current is created. Through the equivalent transformation of converter circuit during thyristor reverse recovery period, the analytical expressions about the relationship between commutating over-voltage and RC value are derived based on the Kirchhoff’s equation. Utilizing the analysis results, the optimal resistance and capacitance value can be selected by considering the reduction of peak over-voltage value and snubber power loss. It turns out that the proposed approach is available through the commutating over-voltage simulation and experiment results of high power converter.

A Zero-Voltage Switching Three-Phase Inverter

A new modulation scheme for the active clamping zero-voltage switching (ZVS) inverter is proposed. With the proposed modulation scheme, the inverter can realize ZVS operation in all switching devices and can remarkably suppress the reverse recovery current in insulated-gate bipolar transistor's antiparallel diodes as well. All the switches can operate at a fixed frequency in the new modulation scheme. Also, with the new modulation scheme, the ZVS inverter has some voltage boost capability, which is suitable for renewable energy generation. The inverter can achieve ZVS in all the switches under the grid current power factor angle from zero to ±π/6. The soft-switching condition of this inverter is analyzed. The operation principal and design guideline are described in detail. The previous theory is verified in a 30-kW inverter prototype.

EMI Generation Characteristics of SiC and Si Diodes: Influence of Reverse-Recovery Characteristics

Silicon carbide (SiC) Schottky diodes with zero reverse-recovery current (RRC) are perceived as superior due to their reduced switching losses. The absence of reverse-recovery behavior in these devices is also expected to result in reduced electromagnetic interference (EMI), compared with the conventional silicon (Si) PIN diodes. In this letter, the influence of SiC Schottky diodes on EMI generation in hard-switched power converters is investigated. A simplified analytical model enabling the spectral envelope of the diode current waveform to be predicted is presented. Numerical simulations and experimental tests are employed to validate this model. It is found that although the reverse-recovery characteristics are very different between Si diodes and SiC Schottky diodes, the actual improvement with SiC diodes on the spectral content of the diode current waveforms is relatively small except at frequencies around 5 MHz. Factors affecting the EMI performance such as the peak amplitude and the “snappiness” of the RRC are also analyzed. Experimental measurements of the switching current waveforms for both Si diodes and SiC diodes are presented and their frequency spectra are compared.

S1920204 超小型衛星TSUBAME搭載用電源回路のスパイクノイズ対策([S192-02]宇宙システムに関する実践的解決と知見の汎用化(2),宇宙工学部門)

In this paper, we reported measures against spike noises in a charger circuit of the micro-satellite "TSUB AME" which has high power consumption (MAX 68W). The spike noises occurred from an FET as a switching regulator in the Li-ion battery charger circuit. The main cause of the spike noises was pattern design and another cause was that choices of FET and inductor weren't optimal. Thus, by major upgrade of EPS circuits, the inductor is changed to another inductor which the self-resonant frequency is higher than frequencies of the spike noises, and the FET is also changed to an FET with low reverse recovery current. As a result, there are no spike noises in the charger circuit.

태양광 최대 전력 추종기를 위한 고효율 무손실 스너버

A new passive lossless snubber for boost converter based on magnetic coupling is proposed. It is composed of a winding coupled with boost inductor, one snubber inductor, two snubber capacitor and three additional diodes. Especially, the snubber inductor can not only limit the reverse recovery current of output diode but also minimize switch turn-on losses greatly. Moreover, all of the energy stored in the snubber is transferred to the load in the manner of resonance. To confirm the validity of proposed system, theoretical analysis, design consideration, and verification of experimental results are presented.

A Novel Fast Recovery Diode with Lower Emitter Efficiency

In this paper, a new structure of Fast Recovery Diode (FRD) and its manufacture methods were investigated. The active region designed by TCAD simulation software could achieve low emitter injection efficiency, and then reduce the peak reverse recovery current, improve the reverse recovery softness and increase working stability. Meanwhile, the effect of the P-body dose and carrier lifetime on the turn-off characteristic of FRD was also discussed. Taking an example of 3300V voltage grade devices for FRD, the reasonable P-body dose and carrier lifetime on the basis of the new structure were confirmed by simulations. This diode was suitable for the anti-parallel with power switch device (such as IGBT, GTO, etc.).

Automatic Measurement and Modeling Implementation of Diode Reverse Recovery

Diode reverse recovery current dissipation is the most important source of power dissipation for diodes used in fast switching converters or other power devices applications. As the reverse recovery current can peak at very high currents, this may cause the failures of other devices in the circuit. Therefore the Diode Reverse Recovery phenomena should no longer be ignored in device model and circuit simulations employing diodes. Automatic measurement of Diode Reverse Recovery time is becoming essential for mass production industrial process monitoring and device modeling. In this paper, a novel Sagittarius automatic Diode Reverse Recovery Time Measurement System was developed. This system has enabled the automation measurement and improved the measurement speed for about 5-7 times. A new Verilog A Diode Reverse Recovery model which can reflect the actual device characteristics was developed base on the data measured using this new system.

A Comparative Performance Study of an Interleaved Boost Converter Using Commercial Si and SiC Diodes for PV Applications

A performance comparison of an interleaved boost converter (IBC) using Si and SiC diodes for photovoltaic (PV) energy conversion systems is presented in this paper. The performance attributes under investigation include the semiconductor device behavior, thermal requirement, system efficiency, and power density. The IBC is designed to sustain the dc-link voltage in the energy conversion system and to provide the maximum power point tracking in the PV system. Due to the absence of reverse recovery current in SiC Schottky diodes, low switching losses are generated in diodes and switches. This benefit results in a higher system efficiency and smaller cooling system design requirement. As a benefit, the volume and weight of the heatsink can be further reduced. Furthermore, behaviors of the power semiconductors, which will impact the performance in the system, are discussed in the paper. The validity of the analysis is confirmed experimentally with a 2.5-kW IBC prototype with relatively wide power and input voltage operating range. The overall performance of the IBC prototype using Si and SiC diodes is summarized in a table for easy comparison.

A Novel DC-Side Zero-Voltage Switching (ZVS) Three-Phase Boost PWM Rectifier Controlled by an Improved SVM Method

A novel active clamping zero-voltage switching three-phase boost pulsewidth modulation (PWM) rectifier is analyzed and a modified minimum-loss space vector modulation (SVM) strategy suitable for the novel zero-voltage switching (ZVS) rectifier is proposed in this paper. The topology of the novel ZVS rectifier only adds one auxiliary active switch, one resonant inductor, and one clamping capacitor to the traditional hard-switched three-phase boost PWM rectifier. With the proposed SVM strategy, the novel ZVS rectifier can achieve ZVS for all the main and auxiliary switches. In addition, the antiparallel diodes can be turned OFF softly, so the reverse recovery current is eliminated. Besides, the voltage stress of all the switches is equal to the dc-link voltage. The operation principle and soft-switching condition of the novel ZVS rectifier are analyzed. The design guidelines of the soft switched circuit parameters are described in detail. A DSP controlled 30 kW prototype is implemented to verify the theory.

A Design of Cascaded Multilevel Inverter Snubber Circuit

The high frequency induction heating power supply has received increasing attention from researchers, multilevel converter is a high voltage large power application areas of research focus and core, it solves the problem of the multilevel inverter output voltage waveform adjustment, avoids the problem of two times reversing that the load voltage in the commutation during the dead period occurred. An effective way to improve efficiency is to keep the power device of low voltage stress and less switching loss. A passive lossless snubber circuit is designed for inhibiting the reverse recovery current of diode and improving the turn-on condition of powers switch. The operation process of snubber circuit is analyzed and the parameter design method is given. The results of simulation have verified the validity of design methods and the conclusions given by theoretically analyzing in this paper.

A ZVS Grid-Connected Three-Phase Inverter

A six-switch three-phase inverter is widely used in a high-power grid-connected system. However, the antiparallel diodes in the topology operate in the hard-switching state under the traditional control method causing severe switch loss and high electromagnetic interference problems. In order to solve the problem, this paper proposes a topology of the traditional six-switch three-phase inverter but with an additional switch and gave a new space vector modulation (SVM) scheme. In this way, the inverter can realize zero-voltage switching (ZVS) operation in all switching devices and suppress the reverse recovery current in all antiparallel diodes very well. And all the switches can operate at a fixed frequency with the new SVM scheme and have the same voltage stress as the dc-link voltage. In grid-connected application, the inverter can achieve ZVS in all the switches under the load with unity power factor or less. The aforementioned theory is verified in a 30-kW inverter prototype.

A compact repetitive high-voltage nanosecond pulse generator for the application of gas discharge

Uniform and stable discharge plasma requires very short duration pulses with fast rise times. A repetitive high-voltage nanosecond pulse generator for the application of gas discharge is presented in this paper. It is constructed with all solid-state components. Two-stage magnetic compression is used to generate a short duration pulse. Unlike in some reported studies, common commercial fast recovery diodes instead of a semiconductor opening switch (SOS) are used in our experiment that plays the role of SOS. The SOS-like effects of four different kinds of diodes are studied experimentally to optimize the output performance. It is found that the output pulse voltage is higher with a shorter reverse recovery time, and the rise time of pulse becomes faster when the falling time of reverse recovery current is shorter. The SOS-like effect of the diodes can be adjusted by changing the external circuit parameters. Through optimization the pulse generator can provide a pulsed voltage of 40 kV with a 40 ns duration, 10 ns rise time, and pulse repetition frequency of up to 5 kHz. Diffuse plasma can be formed in air at standard atmospheric pressure using the developed pulse generator. With a light weight and small packaging the pulse generator is suitable for gas discharge application.

Characterization of Fast Switching Capability for Diamond Schottky Barrier Diode

Wide band gap semiconductors have been attracted as the material for fabricating power switching devices to obtain lower power conversion loss in high voltage circuit, and to operate harsh environment of high temperature. This paper focuses on diamond as the wide band gap semiconductor material and elucidates the dynamic characteristics in switching operation. To this end, Schottky barrier diode (SBD) is fabricated with p type diamond semiconductor and static I-V characteristics is evaluated. Then, the switching operation of diamond SBD is demonstrated, and forward current dependency of the recovery phenomena is characterized. The diamond SBDs show superior fast switching capability with low reverse recovery current, which is inherent in uni-polar switching device.

Analysis of two resonant converters with the same converter leg

A new series resonant converter composed of two resonant circuits with the same converter leg is presented to achieve the zero-voltage switching (ZVS) turn-on of power switches at a wide range of input voltage and load conditions and zero-current switching (ZCS) turn-off of rectifier diodes in a low input voltage case. Thus, the switching losses of power switches and reverse recovery current on rectifier diodes are improved. If the minimum dc voltage gain of the proposed converter is properly selected, the output voltage can be regulated at no-load condition. Two resonant converters using the same power switches are operated by the phase shift half-switching cycle. Thus, the current ripple at the input terminal capacitor can be reduced. In order to reduce the current stresses of output diodes, the output sides of two resonant converters are connected in parallel. The root mean square currents on transformer secondary windings, transformer copper losses and thermal losses can be further reduced. The output voltage doubler topology is adopted in the output side such that the voltage stress of rectifier diodes is equal to the output voltage instead of two times the output voltage in the conventional centre-tapped rectifier topology. Based on the resonant behaviour, all switches are turned on at ZVS and rectifier diodes are turned off at ZCS if the switching frequency is less than the series resonant frequency. The laboratory experiments with a 1000 W prototype are provided to verify the effectiveness of the proposed converter.

Turn-on Performance of Reverse Blocking IGBT (RB IGBT) and Optimization Using Advanced Gate Driver

Turn-on performance of a reverse blocking insulated gate bipolar transistor (RB IGBT) is discussed in this paper. The RB IGBT is a specially designed IGBT having ability to sustain blocking voltage of both the polarities. Such a switch shows superior conduction but much worst switching (turn- on) performances compared to a combination of an ordinary IGBT and blocking diode. Because of that, optimization of the switching performance is a key issue that makes the RB IGB not well accepted in the real applications. In this paper, the RB IGBT turn-on losses and reverse recovery current are analyzed for different gate driver techniques, and a new gate driver is proposed. Commonly used conventional gate drivers do not have capability for the switching dynamics optimization. In contrast to this, the new proposed gate driver provides robust and simple way to control and optimize the reverse recovery current and turn-on losses. The collector current slope and reverse recovery current are controlled by the means of the gate emitter voltage control in feedforward manner. In addition, the collector emitter voltage slope is controlled during the voltage falling phase by the means of inherent increase of the gate current. Therefore, the collector emitter voltage tail and the total turn- on losses are reduced, independently on the reverse recovery current. The proposed gate driver was experimentally verified and the results presented and discussed.

Passive Lossless Snubber for Boost PFC With Minimum Voltage and Current Stress

A passive lossless snubber for boost power-factor corrector (PFC) is presented. It has a number of advantages over the prior art. First, it does not introduce extra voltage and current stress on the main switch. Second, it provides soft-switching conditions for the main switch over wide input and load range. Third, it limits the turn- on current of the main switch resulting from the reverse recovery current of the output diode. The operating principle of the proposed snubber and procedure of designing the component values are given. A comparative study into the performance characteristics between the prior-art passive lossless snubbers and the proposed snubber will be performed. The performance of the proposed snubber has been evaluated experimentally on a 750-W PFC with universal input. The boost converter is operated in continuous conduction mode and its input current is shaped by using average current-mode control. Experimental results show that soft switching of the main switch is maintained over 88% with an input of 110 V, 60 Hz, and 91.8% an the input of 220 V, 50 Hz, over one line cycle, and from full load to 20% load. The efficiencies of the PFC with unsnubbered hard switching, conventional resistor-capacitor-diode snubber, and proposed snubber will be compared. Results show that the proposed snubber can significantly improve the efficiency over the designed operating range.

High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC–DC converter and a single-phase full-bridge DC–AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC–DC converter. The proposed step-up DC–DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC–DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC–DC converter and the DC–AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current.

A Modified SEPIC Converter for High-Power-Factor Rectifier and Universal Input Voltage Applications

A high-power-factor rectifier suitable for universal line base on a modified version of the single-ended primary inductance converter (SEPIC) is presented in this paper. The voltage multiplier technique is applied to the classical SEPIC circuit, obtaining new operation characteristics as low-switch-voltage operation and high static gain at low line voltage. The new configuration also allows the reduction of the losses associated to the diode reverse recovery current, and soft commutation is obtained with a simple regenerative snubber circuit. The operation analysis, design procedure, and experimental results obtained from a 650-W universal line power-factor-correction prototype of the proposed converter are presented. The theoretical analysis and experimental results obtained with the proposed structure are compared with the classical boost topology.

Analysis and implementation of an active-clamping zero-voltage turn-on switching/zero-current turn-off switching converter

A new isolated dc/dc converter with zero-voltage turn-on switching (ZVS) of power switches and zero-current turn-off switching (ZCS) of diodes is presented. In conventional flyback converters, the main drawbacks are high voltage stresses on power devices, large transformer size and serious reverse recovery current, which resulted in high voltage spikes across output diode. To solve these problems, a buck-boost type of active-clamp circuit is connected in parallel with the primary winding to clamp the voltage spike across the power switch, to recycle the energy stored in the leakage and magnetising inductances of the transformer and to realise the turn-on ZVS by utilising the leakage inductance and output capacitance of the switch. The leakage inductance and the resonant capacitance on the secondary side are resonant to allow the output diodes to turn off at ZCS. Thus, the switching losses and thermal stresses of switches and diodes are reduced, the output diode has no reverse recovery problem and voltage stresses of the output diodes are clamped to the output voltage. Experiments conducted on a laboratory prototype rated at 270 W are provided to verify the effectiveness of the proposed converter.