DC Link Reactor

In high-power VFD and power conversion systems, the rectifier stage converts AC power into DC power before supplying the inverter section. During this conversion process, DC bus current may contain ripple components caused by rectification characteristics, load fluctuation, and regenerative operation.

Dufew Electric DC Link Reactor is installed in series between the rectifier and inverter sections of the DC bus circuit. By providing inductive energy storage, it smooths current variation, maintains continuous DC current flow, and reduces electrical stress on DC capacitors and power semiconductor devices.

Unlike conventional AC reactors, it is specially designed for continuous DC current operation. The segmented air-gap magnetic structure improves DC bias resistance, reduces magnetic saturation risk, and maintains stable inductance performance during long-term industrial operation.

Dufew uses low-loss cold rolled silicon steel cores, Class F insulation systems, precision winding processes, and vacuum impregnation technology to achieve reliable thermal performance, insulation strength, and mechanical stability.

How DC Link Reactor Improves System Reliability

1. Reduce DC Current Ripple and Improve Bus Stability

During AC-DC conversion, voltage fluctuations from the rectifier stage can introduce ripple current into the DC bus. The reactor smooths the DC current waveform, reduces ripple components, and improves inverter input stability while helping reduce stress on DC bus capacitors. This is particularly beneficial for high-power drive systems that require a stable DC energy supply.

2. Maintain Continuous DC Current Flow

In applications with fluctuating loads or unstable power conditions, excessive current pulsation can affect inverter operation. By reducing current discontinuity and maintaining a more continuous rectifier current, the reactor supports stable inverter switching and helps reduce abnormal operating conditions during dynamic operation.

3. Protect DC Bus Capacitors and Power Components

High ripple current can accelerate DC capacitor aging and increase thermal stress on power components. The optimized design limits current pulsation and reduces ripple stress on capacitors, helping improve the reliability of DC bus components and extend the service life of the overall drive system.

4. Improve Input Power Factor Performance

By smoothing the DC current characteristics, the reactor can improve the electrical performance of the converter system. Reduced current distortion contributes to better energy utilization and improved compatibility with high-power electrical systems.

Core Structural Design Features

Segmented Air-Gap Core Design for DC Bias Resistance

Continuous DC current produces a unidirectional magnetic field that can cause conventional magnetic cores to approach saturation. Dufew adopts a segmented air-gap core structure to reduce DC saturation risk while maintaining stable inductance and effective current smoothing performance. This design supports reliable operation under continuous DC loads.

Low-Loss Winding Structure

The winding structure is optimized for high-current DC operation, helping reduce DC resistance loss and temperature rise while maintaining stable electrical performance and efficient heat management. For high-current applications, foil winding structures can also be provided to reduce overall size and improve heat dissipation.

Vacuum Impregnation Insulation System

The vacuum impregnation process strengthens the insulation system and improves moisture resistance, mechanical strength, and vibration resistance. Combined with the optimized structural design, it supports reliable long-term operation while maintaining low electromagnetic vibration and noise levels of ≤65dB under standard testing conditions.

Typical Applications

Recommended Selection Conditions

A DC Link Reactor is recommended when:

Technical Specifications

Model Number Explanation

Example: CDL-600-0600-EIDA

DC Link Reactor vs AC Reactor

Manufacturing Capability & Quality Assurance

Dufew Electric specializes in manufacturing power electronics components including reactors, braking resistors, transformers, and customized electrical solutions.

Dufew's manufacturing process covers magnetic core processing, precision winding, vacuum impregnation, high-temperature curing, and electrical performance testing. Each stage is controlled to maintain consistent electrical characteristics and reliable product quality.

Quality inspection covers insulation resistance, withstand voltage, inductance, temperature rise, and appearance. These tests verify the reactor's electrical performance, insulation reliability, thermal characteristics, and overall manufacturing quality.

For different project requirements, Dufew provides OEM manufacturing and custom electrical design, together with engineering consultation and technical documentation support. This allows the product to be adapted to specific electrical parameters, installation conditions, and system applications.

FAQ

Q1: Where is a DC Link Reactor installed?

A DC Link Reactor is installed in the DC bus circuit between the rectifier and inverter sections of a VFD or power conversion system. It helps smooth DC current fluctuation, reduce ripple components, and improve DC bus stability.

Q2: What is the difference between this product and an AC reactor?

The main difference is the application circuit. An AC reactor is used in AC circuits to reduce harmonics, limit current impact, and improve power quality. This product is designed for DC bus applications to smooth current ripple and protect DC-side components.

Q3: Why does this product require an air-gap core design?

Continuous DC current can create magnetic bias in the core. The segmented air-gap structure helps prevent magnetic saturation, maintain stable inductance, and ensure reliable operation under DC conditions.

Q4: Can Dufew customize specifications for different applications?

Yes. Dufew provides customized solutions including voltage rating, current capacity, inductance value, winding material, installation structure, and mechanical dimensions according to different system requirements.