Snubber Circuit Design Research Articles

Current oscillation elimination for the helicopter transient electromagnetic inverter based on pole configuration

In a helicopter transient electromagnetic system, the quality of the transmitting-current waveform will affect the geological exploration effect. In this paper, a helicopter TEM inverter, based on a single-clamp source and pulse width modulation technology, is designed and analyzed. Besides, it finds that there will be current oscillation in the early measuring stage. For this problem, first, the factors that cause the current oscillation are analyzed. Then, it is proposed to apply the RC snubber to eliminate this current oscillation. Since the imaginary part of the pole is the essence of oscillation, configuring the pole can eliminate the current oscillation. By establishing the early measuring stage system model, the characteristic equation of the load current with the snubber circuit is deduced. Next, the characteristic equation is solved by the exhaustive method and the root locus method to obtain the parametric region that eliminates the oscillation. Finally, through simulation and experimental verification, the proposed snubber circuit design method can be used to eliminate the early measuring stage current oscillation. Compared to the method of switching into the damping circuit, it can achieve the same performance, more important is that there is no switching action and it is easy to achieve.

Dynamic Modeling Framework for Evaluating Electromagnetic-Electro-Thermal Behavior of Power Conversion System During Load Operation

Abstract This study introduces a modified dynamic multiphysics modeling framework to characterize the electromagnetic-electrothermal (EET) coupled behavior of a power conversion system during a long load operation. The modeling framework extends the prior model with more comprehensive analysis and enhanced computational efficiency and modeling simplicity. This framework incorporates a fully integrated electromagnetic circuit (FIEC) model for extracting parasitics, including self and mutual inductances and also exploring their effect on the switching characteristics and power losses, and a dynamic power loss-temperature thermal (PTT) model for describing the temperature-dependent instantaneous electrical behavior and power loss. Moreover, a simple resistance-capacitance (RC) snubber circuit design is applied to prevent overvoltage and diminish voltage oscillations and spike value during the operation, and their power losses are also assessed and considered in the dynamic EET coupled modeling. Furthermore, the proposed PTT model employs an equivalent thermal RC network to calculate the chip junction temperature with a given power. Additionally, a simple power-temperature relationship derived from the FIEC cosimulation is applied for modeling simplicity and computational efficiency. This framework is tested on a three-phase inverter operating with a 180-deg conduction mode. The proposed FIEC cosimulation and computational fluid dynamics thermal models are validated by double pulse (DPT) and infrared thermography experiments, respectively. Moreover, the PTT model is validated compared with the conventional dynamic coupled electrothermal model. Finally, a design guideline for enhanced thermal performance of the tested power conversion system is sought through parametric analysis.

1㎸, 1㎄, 12㎾ 펄스 출력을 위한 Discharge Closing Switch의 스너버 회로 설계

This paper deals with the overall structure of 1㎸, 1㎄, and 12㎾ pulse modulator and the snubber circuit design of the discharge closing switch for pulse. This high-voltage, high-current pulse modulator is used in various fields such as the field of printed electronics. However, overshoot and noise are unavoidable considerations due to the features of pulse power that instantaneously outputs high voltage and current. To reduce such overshoot and noise, a snubber circuit has been proposed. The snubber circuit consists of a resistance, capacitor, diode(RCD) and is additionally equipped with one more capacitor. Therefore, in this paper, we analyze the operational principles of the proposed snubber circuit. Finally, a waveform without overshoot and malfunction was confirmed through a pulse output experiment.

Reducing Electromagnetic Interference in Three-Level T-type Isolated Bidirectional DC-DC Converter Using a Snubber Circuit

Electromagnetic interference is the main problem in high switching power converters like DC-DC converters. One of the solution methods for electromagnetic interference reduction is to design a snubber circuit. The snubber circuit is a practical method to reduce fluctuations caused by parasitic components from the layout and non-ideal characteristics of switching devices. An effective snubber circuit design increases the converter's efficiency and reduces EMI noise. In this paper, electromagnetic interference is reduced using different snubber circuits in a three-level T-type isolated bidirectional DC-DC converter. The converter is simulated in PSIM to see the effectiveness of the noise reduction with the snubber circuits. CISPR 25 standard is used for the compliance assessment in the study.

Design of lossless snubber circuit for phase-shifted full-bridge converter

In the phase-shifted full-bridge circuit, the voltage spike caused by the hard turn-off of the switch tube increases the voltage stress of the switching device. Due to the existence of energy-consuming components such as resistance in the traditional absorption circuit, the efficiency is not always high. Based on the RCD snubber circuit, a low-loss absorption circuit is designed in this paper. This circuit absorbs voltage spikes through an absorption capacitor, and then slowly releases energy through an oscillating circuit consisting of current-limiting inductance, stray inductance, and absorption capacitance. The current-limiting inductance reduces the current stress of the blocking diode effectively, which can be achieved with the absorption not being affected and the power loss being reduced. Finally, the absorption effect and energy loss of the new low-loss absorption circuit and the commonly used RCD circuit were simulated and compared in PSpice software, and verified its feasibility.

스위칭 특성을 고려한 전류형 HVDC 시스템의 댐핑회로 설계 적정성 검토

스위칭 특성을 고려한 전류형 HVDC 시스템의 댐핑회로 설계 적정성 검토

Optimal design of RC snubber circuit for mitigating transient overvoltage on VCB via hybrid FFT/Wavelet Genetic approach

This paper presents a new approach to the analysis of the transient overvoltage (TOV) generated during switching of vacuum circuit breaker (VCB). The new technique overlaps the merits of both Fast Fourier Transform (FFT) and Wavelet Transform (WT). The new approach was applied on a real case study of a pumping station of a wastewater treatment plant located at Abu Rawash, Egypt. The pumping station is driven by induction motors. Alternative transients program (ATP) is used to simulate the selected case study. The Referential Integrity between FFT and WT analyses (RI-FFT/WT) is employed to choose the RC snubber circuit parameters (R and C). The optimal snubber circuit parameters design was determined from the hybridization between genetic algorithm (GA) and RI-FFT/WT. It is evident from the simulation results that the new hybrid GA-FFT/WT approach succeeded in the selection of the most optimal RC-snubber circuits required for the mitigation of the TOV.

Analysis and design of snubber circuit for Z‐source inverter applications

The Z-source inverter (ZSI) is a topology with many advantages for power electronics interfaces. Shoot-through states are utilised to boost the DC-link voltage. This study shows that traditional C, RC, RCD, and RCD clamp snubber circuits are not suitable for ZSI. When these snubber circuits are used for ZSI, there will be a distortion in the DC-link voltage, and this voltage will be higher than that without the snubber circuits. The shoot-through state causes larger energy losses, which greatly lowers the efficiency of ZSI. This study presents an improved RCD snubber circuit for ZSI applications. This design reduces the voltage distortion and energy losses. In addition, the theoretical analysis and design guidelines for snubber circuits of ZSI are confirmed by computer simulation and experimental verification.

Snubber Design for Transformer Protection

Historically, failures of distribution transformers due to transient overvoltage phenomena have led to the development of resistor–capacitor snubber circuits for the protection of the transformer and winding insulation. These transients are most often observed when dry-type transformers are close coupled to vacuum switching devices. Typically, snubber circuit design has been specific for the particular application, and complex engineering studies were required. However, the design of a snubber circuit itself may be performed without these detailed studies. If snubber studies are required, the procedures for system modeling and simulation are explained in a step-by-step manner.

Snubber Circuit Design for Transformers in an Urban High Rise Office Building

Transformer failures have in recent years led to the development of resistor-capacitor snubber circuits for the protection of the transformer and winding insulation from the damaging effects of high-voltage high-frequency transients. Transformer insulation may be damaged if the basic insulation level is exceeded, during turn-to-turn insulation, when there is excessive rate of change of voltage with time (dv/dt), and in switching devices by restrikes when the transient recovery voltage is exceeded. These transients are most often observed when dry-type transformers are closely coupled to vacuum switching devices. Some manufacturers are now including snubbers in their transformer designs. This paper provides a thorough review of the causes of the transients, methods of analysis, and mitigation of the effects of these transients. An example is provided of transformers to be installed in the basement of an urban high rise office building (where the space is limited and the available fault current is high), where the transformer enclosure includes built-in snubber circuits. The strengths and weaknesses of current methods are examined. Recommendations are made for improvements in snubber circuit design and analysis.

RC Snubber Circuit Design for ITER PF Converter Module

The proper RC snubber circuit is of great importance to protect the thyristor against overvoltage during the turn-off process. This paper mainly presents the design of commutating over-voltage RC snubber circuit for ITER poloidal field (PF) converter module. Based on the reverse recovery transient model of the multi-parallel thyristors and commutating overvoltage circuit model, the RC snubber parameters of PF converter module are obtained by the detailed theoretical calculations, and then the simulation analysis and the commutating overvoltage test of the prototype are done to verify the RC snubber components selection, the simulation and test results show that the design of RC snubber circuit can meet the commutating overvoltage protection requirement.

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.

Research on Commutating Over-Voltage Protection for ITER Poloidal Field Converter

This paper presents the commutating over-voltage snubber circuit design method of a thyristor converter that is applied to the International Thermonuclear Experimental Reactor poloidal field-converter module. In the course of poloidal field ac/dc converter normal operation, large transient surges called commutating over-voltages may be generated internally during the commutating process of thyristor, which poses a severe threat to system reliability and needs to be suppressed. In this paper, based on the analysis of reverse recovery transient of the parallel thyristors, the turn-off model of the PF converter thyristor is created and analytical expressions are derived, including the over-voltage crest value and the maximum over-voltage rise rate. Utilizing the analysis results, a systematic approach to the RC snubber circuit design is described.

Principle of Surge Voltage of a Rectifier in Isolated DC-DC Converters and Snubber Circuit Design Method

Principle of Surge Voltage of a Rectifier in Isolated DC-DC Converters and Snubber Circuit Design Method

A modified non-dissipative LC snubber circuit for MOSFET based fly-back converters

High frequency converters with different switching topologies are now being widely used over a wide range of applications, which mainly includes different types of power supplies. Snubber circuit design for high frequency-switched converters using MOSFET as a power device assumes different dimension as regards the minimisation of the power dissipation in the snubber resistance. This paper shows a different mode of operation to reduce the clamp voltage across the device used in fly-back type converter. The LC snubber circuit is almost lossless and of energy regenerative type. A reduced clamp voltage is required not only for device protection, but also to reduce the cross regulation effect in multiple output converters. Simulations and experimental results validate the concept.

Pulsed-duty characterization of turn-off for a population of SCRs and the effect of variation on equalization circuit design

Turn-off characteristics of silicon-controlled rectifiers (SCRs) drive the design of snubber circuits for single devices in power converters. Turn-off characteristics also drive the design of equalization circuits for series-connected devices in power converters. For single devices, the important characteristics are peak recovery current, recovery time, and recovered charge. These characteristics are also important for series-connected devices, but it is the variation in these characteristics that define the equalization requirements. In fact, these variations are used to determine the size and power dissipation of the equalization circuit. A population of SPCO 402b pulse-rated silicon controlled rectifiers was tested and recovery characteristics were measured. The differences in recovery characteristics were tabulated and discussed. A method of equalization circuit design based on circuit variations was discussed and circuit design trades are made in light of the variations in recovery characteristics.

Analysis and design of snubber circuits for high-power GTO DC-DC converters

This paper presents the analysis and the design of snubber circuits for high power DC-DC converters realized with gate turn off thyristors. These networks are fundamental for the safe operation of semiconductor devices but dissipate some energy. Means to minimize their losses are studied in this work. The snubber circuits described here are an evolution of the conventional C-snubber and L-snubber. The design of the snubbers is based upon circuits that permit the transfer of the trapped energy to the power source or to the load. Benefits, drawbacks and limits of each new proposed circuit are detailed and studied. Experimental results, obtained from a GTO laboratory prototype converter are reported. >

Design of a thyristor snubber circuit by considering the reverse recovery process

Design procedures are presented for the snubber circuit in power electronic circuits by considering the reverse recovery process of the thyristor. The thyristor turnoff model, whose parameters are determined for best fitting to the device characteristics given on the data sheets, is applied to analyze the behavior of the snubber circuit with and without a saturable reactor during the reverse recovery time of the power device. Based on the turnoff model, exact expressions are derived for various quantities of interest including the maximum device stress, maximum reverse dv/dt, the reverse energy loss of a power device, and the total turnoff loss in the device plus the associated snubber circuit. Utilizing the analysis results, a systematic approach to the snubber-circuit design with the stray inductance taken into account is described. It is concluded that the proposed approach is very useful in the simulation of turnoff characteristics of the power device, snubber-circuit designs, and loss calculations in power circuits.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Computer-aided design of power transistor inverter snubber circuits

The conventional voltage-source inverter snubber circuit has been examined in detail by computer simulations. A new snubber arrangement is proposed and analysed. It aims to reduce the transient voltage overshoot without incurring excessive switching losses. Also, the reverse-recovery processes of the snubber diodes are controlled so that the requirement for fast snubber diodes is not mandatory. Computer simulations by the program SPICE have been used throughout the analysis and design process, and hence have been proved to be a useful design tool.

Snubber Circuit for High-Power Gate Turn-Off Thyristors

A snubber circuit calculation model for high-power gate turn-off thyristors (GTO's) was proposed to consider problems which must be investigated for snubber circuit design. The calculated GTO waveforms showed good agreement with experimental values obtained by a GTO chopper circuit for both a resistive and inductive load case. Problems to be considered for the snubber design, such as voltage spike reduction, maximum GTO anode current, and switching power, were discussed using the calculation model. Design criteria for the snubber circuit were successfully established, introducing allowable maximum voltage spikes to avoid failures due to current crowding during the GTO interval and excessive voltage applied over maximum blocking voltage rating. Minimum switching power loss dissipated inside the GTO and the snubber resistor was also calculated, taking the design criteria into consideration. As results of the calculations, the snubber circuit stray inductance was found to play an important role in optimizing the minimum switching power loss, especially for large anode current and large stray inductance in a main circuit. 1983.