Passive Components Blog
No Result
View All Result
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    Samsung Electro-Mechanics High Capacitance MLCCs for ADAS SoCs

    Murata Expands its Automotive Common Mode Choke Coils to 150C and High Current Capability

    Bourns Releases New Current Transformer

    Skeleton Releases GrapheneGPU to Reduce AI Energy Consumption by 44% and Boosts Power by 40%

    VINATech Expands Aluminum Capacitor Portfolio with Acquisition of Enesol

    binder Offers Wide Range of M12 Panel Mount Connectors

    Bourns Releases New Shielded Power Inductors for DDR5

    Supercapacitors Benefits in Industrial Valve Fail-Safe Control Systems

    Wk 21 Electronics Supply Chain Digest

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Coupled Inductors Circuit Model and Examples of its Applications

    Inductor Resonances and its Impact to EMI

    Highly Reliable Flex Rigid PCBs, Würth Elektronik Webinar

    Causes of Oscillations in Flyback Converters

    How to design a 60W Flyback Transformer

    Modeling and Simulation of Leakage Inductance

    Power Inductor Considerations for AI High Power Computing – Vishay Video

    Coupled Inductors in Multiphase Boost Converters

    VPG Demonstrates Precision Resistor in Cryogenic Conditions

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    Samsung Electro-Mechanics High Capacitance MLCCs for ADAS SoCs

    Murata Expands its Automotive Common Mode Choke Coils to 150C and High Current Capability

    Bourns Releases New Current Transformer

    Skeleton Releases GrapheneGPU to Reduce AI Energy Consumption by 44% and Boosts Power by 40%

    VINATech Expands Aluminum Capacitor Portfolio with Acquisition of Enesol

    binder Offers Wide Range of M12 Panel Mount Connectors

    Bourns Releases New Shielded Power Inductors for DDR5

    Supercapacitors Benefits in Industrial Valve Fail-Safe Control Systems

    Wk 21 Electronics Supply Chain Digest

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Coupled Inductors Circuit Model and Examples of its Applications

    Inductor Resonances and its Impact to EMI

    Highly Reliable Flex Rigid PCBs, Würth Elektronik Webinar

    Causes of Oscillations in Flyback Converters

    How to design a 60W Flyback Transformer

    Modeling and Simulation of Leakage Inductance

    Power Inductor Considerations for AI High Power Computing – Vishay Video

    Coupled Inductors in Multiphase Boost Converters

    VPG Demonstrates Precision Resistor in Cryogenic Conditions

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
No Result
View All Result
Passive Components Blog
No Result
View All Result

IGBT Snubber Capacitors Selection Guide

24.8.2022
Reading Time: 6 mins read
A A

Source: Deki application note and article

Important developments of IGBT’s (Insulated Gate Bipolar Transistors) over the years have been focused on increasing power handling capability and increasing reliability. Snubber capacitors have also undergone changes in construction enabling increased power handling capability. This ‘charge’ focuses on giving the reader a brief overview on the IGBT Snubber capacitor.

RelatedPosts

Snubber Capacitors Functionality and Selection Guide

TDK Releases its Application Guide on Motor/Inverter Circuit Configuration

What Ceramic Technologies Are Best for High Power Density Applications?

Power systems containing IGBTs must be designed so the transient voltage caused by the high dI/dt that occurs at gate turn off is minimized. Left uncontrolled, this transient voltage can exceed the blocking voltage rating of the IGBT and cause it to fail. In order to minimize the transient voltage a wound construction polypropylene film capacitor mounted as close to the IGBT terminals as possible is usually recommended. (See picture below; credit: Deki Electronics)

The acceptable amount of overshoot voltage is determined by the maximum DC voltage that an inverter power circuit is subject to and the IGBT voltage ratings. The peak current to turn off under a fault condition can be as high as 6-10 times the device current rating. This peak current under the fault condition will proportionally increase the overshoot voltage.

The switching capacity with shortest switching times which can be realized using IGBTs makes it necessary to use an extremely low-inductance circuit design. Even the low self-inductance of the power bus may induce dangerous voltage overshoots between collector and emitter which may result in the destruction of the valuable power semiconductors.

Necessity of Using the Snubber Circuit

These are placed across the various switching devices like transistors, thyristors, etc. Switching from ON to OFF state results the impedance of the device suddenly changes to the high value. But this allows a small current to flow through the switching device. This induces a large voltage across the device. If this current reduced at faster rate more is the induced voltage across the device and also if the switching device is not capable of withstanding this voltage the device may burn out. So auxiliary path is needed to prevent this high induced voltage.

Similarly, when the transition is from OFF to ON state, due to uneven distribution of the current through the area of the switch overheating will takes place and eventually it will be burned. Here also snubber is necessary to reduce the current at starting by making an alternate path.

See also article: RC snubber design for SMPS protection.

Snubbers in switching mode provides one or more of the following functions:

  • Shape the load line of a bipolar switching transistor to keep it in its safe operating area.
  • Reducing the transient voltages and currents during turn-ON and turn-OFF conditions.
  • Removes transient energy from a switching device and dissipate the energy in a resistor to reduce junction temperature.
  • Limiting the rate of change of voltage and currents during the transients.
  • Reduce ringing to limit the peak voltage on a switching device and lowering their frequency.

Transient voltage comparison with and without protection snubber capacitor; source: Deki Electronics

Snubber Capacitor Selection Guide:

Capacitor DC-voltage class
The maximum continuously applied DC voltage can be the rated DC voltage of the capacitor in order to ensure longer life of the capacitor. Semiconductors with 1200V blocking voltage are used with up to 900V DC-link voltage. For these applications, capacitors with a rated voltage of 1000V are recommended. For 1700V semiconductors, 1250V or 1600V capacitors are recommended, depending on the DC-link voltage. The peak voltage also has to be in the admissible values because otherwise the plastic film could be damaged. Consider also that the applied DC voltage has to be derated when the capacitor is operating at higher temperatures than the rated temperature.

Capacitance value and series inductance
The capacitance value has to be high enough to achieve sufficient voltage spike suppression during switching off. Typical values for these capacitors are from 0.1 μF to 1.0 μF. But not only is the capacitance value important for this. Also a low inductive design of the capacitor is important. The remaining inductance, caused by the loop between the terminals and the internal connections of the capacitors is responsible for a voltage spike/transient. A high capacitance value is no guarantee for a low voltage spike if the self-inductance remains. A low self-inductance can be achieved by using capacitors with wide flat terminals that can be screwed directly onto the IGBT module terminals. The capacitor should be designed so that the terminals encircle as small an area as possible and that they are directly connected to the capacitor coil without having internal wires between. Furthermore, metallized polypropylene foil capacitors should be used with plastic case according to UL94V-0.

Pulse handling capability
The inner connections of the capacitor are capable of withstanding only a limited amount of energy at each switching event. The data sheets of the supplier specify limits for pulse operation. These values can be calculated from the oscillating current or voltage waveform of the capacitor. This calculation can easily be carried out using modern digital oscilloscopes. A capacitor failure can occur only because of very high peak currents, even when the involved voltages are lower than the specified ones. In this situation the critical thing is the involved energy and normally there will be a loss of connection between metal spray and film metallization. Because of the very high energy involved the film metallization will be vaporized on the connection area to the metal spray. This will lead the capacitor to a high loss factor or even to a capacitance loss. The maximum dv/dt values are less critical because of the damped sinusoidal waveform.

RMS voltage and RMS current
A damped oscillation occurs at each switching event (on or off = twice switching frequency of the IGBT) between the snubber capacitor and the bus bar capacitance. The RMS current leads to self-heating of the capacitor. The capacitor will stabilize at a certain temperature which also depends on the ambient temperature and on the mounting conditions (e.g. temperature of power module terminals). Data sheets give values for the permissible RMS current and RMS voltage depending on the frequency. The oscillating frequency depends on the DC-link stray inductance and the snubber capacitor value. Typical values are in the range of 100 kHz to 1 MHz. The permissible RMS current decreases with the frequency because the losses increase.

Lifetime
The capacitor lifetime and failure rate is mainly affected by the operating temperature and operating voltage. The snubber circuit is formed using both R and C. Hence it is important to have the right selection of the Resistor also. It is important that R in the RC snubber, have low self-inductance. Inductance in R will increase the peak voltage and it will tend to defeat the purpose of the snubber.

Low inductance will also be desirable for R in snubber but it is not critical since the effect of a small amount of inductance is to slightly increase the recovery time of C and it will reduce the peak current in device during switching.

The normal choice of R is usually the carbon composition or metal film. Resistor dissipates the energy stored in the snubber capacitor in each transition. If we select the resistor as that the characteristic impedance, the ringing is well damped.

Latest Snubber Capacitors Construction and Features (Example):

IGBT Snubber Capacitor Construction:

  • Dielectric: Polypropylene film
  • Electrodes: Extended foil electrodes with metallised polypropylene internal series connection
  • Leads: Tinned copper lugs
  • Seal: Plastic case with resin sealing. Flame retardant execution (UL94V-0).

Features:

  • Self-healing capability
  • High-frequency
  • High peak current
  • High DV/DT
  • High peak and RMS current capability
  • Low ESR.

Applications:

IGBT snubber capacitors are used in high voltage, high current and high pulse applications such as:

  • IGBT protection circuits
  • snubber network
  • protection circuits in SMPS, energy conversion and control in power electronics.

Related

Recent Posts

Samsung Electro-Mechanics High Capacitance MLCCs for ADAS SoCs

30.5.2025
2

Murata Expands its Automotive Common Mode Choke Coils to 150C and High Current Capability

29.5.2025
6

Bourns Releases New Current Transformer

29.5.2025
9

Skeleton Releases GrapheneGPU to Reduce AI Energy Consumption by 44% and Boosts Power by 40%

29.5.2025
17

VINATech Expands Aluminum Capacitor Portfolio with Acquisition of Enesol

28.5.2025
34

Bourns Releases New Shielded Power Inductors for DDR5

29.5.2025
18

Supercapacitors Benefits in Industrial Valve Fail-Safe Control Systems

26.5.2025
22

Samsung Electro-Mechanics Releases High-Capacitance MLCCs for AI Server Applications

21.5.2025
53

Coupled Inductors Circuit Model and Examples of its Applications

21.5.2025
68

Würth Elektronik Introduces LTspice Models for ESD Products

21.5.2025
45

Upcoming Events

Jun 4
11:00 - 12:00 CEST

Würth Elektronik PCB Production in Asia

View Calendar

Popular Posts

  • Buck Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Boost Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • LLC Resonant Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Flyback Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • How to Design an Inductor

    0 shares
    Share 0 Tweet 0
  • Ripple Current and its Effects on the Performance of Capacitors

    3 shares
    Share 3 Tweet 0
  • What is a Dielectric Constant and DF of Plastic Materials?

    4 shares
    Share 4 Tweet 0
  • Why Low ESR Matters in Capacitor Design

    0 shares
    Share 0 Tweet 0
  • SEPIC Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Flying Capacitors Explained

    0 shares
    Share 0 Tweet 0

Newsletter Subscription

 

Passive Components Blog

© EPCI - Leading Passive Components Educational and Information Site

  • Home
  • Privacy Policy
  • EPCI Membership & Advertisement
  • About

No Result
View All Result
  • Home
  • Knowledge Blog
  • Premium Suppliers

© EPCI - Leading Passive Components Educational and Information Site

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy and Cookie Policy.
Go to mobile version