INDUSTRY COMPONENT

DC Bus Capacitor

DC bus capacitor is an energy storage component in inverter systems that stabilizes voltage and filters ripple current on the DC link.

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Component Specifications

Definition
A DC bus capacitor is an essential passive component in power electronic converters, particularly in inverters, that connects across the DC link between the rectifier and inverter stages. It serves to smooth the DC voltage by absorbing and releasing electrical energy, reducing voltage ripple caused by switching operations and load variations. This component maintains stable DC bus voltage, prevents voltage spikes, and ensures reliable operation of the inverter's power semiconductor devices.
Working Principle
The DC bus capacitor operates by storing electrical charge when the DC voltage rises above its nominal value and releasing stored energy when the voltage drops. It acts as a low-impedance energy reservoir that supplies instantaneous current demands during switching transitions, while filtering high-frequency harmonics and reducing electromagnetic interference. The capacitor's ability to rapidly charge and discharge helps maintain voltage stability despite rapid load changes and switching frequency variations.
Materials
Typically constructed with aluminum electrolytic capacitors or film capacitors (polypropylene or polyester). Aluminum electrolytic capacitors use aluminum foil electrodes with electrolyte solution, while film capacitors employ metallized polymer films. Materials include: aluminum foil (anode/cathode), electrolyte (boric acid, ethylene glycol), separator paper, aluminum casing, rubber seal, and terminal leads.
Technical Parameters
  • ESR 5mΩ to 50mΩ
  • Lifetime 2000 to 10000 hours at rated temperature
  • Capacitance 100μF to 10000μF
  • Ripple Current 10A to 100A RMS
  • Voltage Rating 400V to 1200V DC
  • Temperature Range -40°C to +105°C
Standards
IEC 60384, IEC 61071, ISO 9001, UL 810

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for DC Bus Capacitor.

DC bus capacitor inverter capacitor DC link capacitor power capacitor electrolytic capacitor film capacitor voltage stabilization ripple current filtering DC Bus Capacitor in Electrical Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Inverter

Electronic device that converts DC power to AC power with variable frequency and voltage

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Engineering Analysis

Risks & Mitigation
  • Overheating due to excessive ripple current
  • Voltage spikes exceeding rating
  • Electrolyte leakage
  • Reduced lifespan at high temperatures
  • Incorrect capacitance causing instability
FMEA Triads
Trigger: Excessive ripple current beyond specification
Failure: Overheating and premature aging
Mitigation: Proper sizing with adequate ripple current rating and thermal management
Trigger: Operating voltage exceeding rated voltage
Failure: Dielectric breakdown and short circuit
Mitigation: Implement overvoltage protection circuits and select capacitors with appropriate voltage derating
Trigger: High ambient temperature operation
Failure: Electrolyte evaporation and capacitance loss
Mitigation: Use high-temperature rated capacitors and ensure adequate cooling

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Capacitance tolerance typically ±20% for electrolytic, ±5% to ±10% for film capacitors
Test Method
IEC 60384-1 for electrical parameters, IEC 60068 for environmental testing, UL 810 for safety certification

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What is the main function of a DC bus capacitor in an inverter?

The primary function is to maintain stable DC voltage by filtering ripple current and providing instantaneous energy during switching operations.

How do I select the right DC bus capacitor for my application?

Consider voltage rating, capacitance value, ripple current capability, ESR, temperature range, and physical size based on your inverter's power rating and switching frequency.

What are common failure modes of DC bus capacitors?

Electrolyte drying, increased ESR, capacitance degradation, terminal corrosion, and internal short circuits due to overvoltage or overheating.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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