Featured Products for High-Efficiency Power Conversion Winding
Explore our high-performance Ohno Continuous Cast (OCC) bare/enameled copper wires, precision litz wires, and custom rectangular magnet wires optimized for power conversion equipment.
Understanding OCC Copper in Power Conversion Device Winding
Modern power conversion systems—ranging from high-frequency switched-mode power supplies (SMPS) and electric vehicle (EV) traction inverters to renewable energy grid tie systems—demand unprecedented levels of efficiency and power density. At the heart of these magnetic components (transformers, inductors, chokes, and resonant coils) is the winding material. Standard Tough Pitch (ETP) and Oxygen-Free Copper (OFC) possess microscopic grain boundaries that scatter electrons, induce internal heating under high dI/dt stresses, and promote skin effect vulnerabilities at megahertz frequencies.
Ohno Continuous Cast (OCC) Copper represents a paradigm shift in metallurgical engineering for power electronics. Developed using a specialized heated mold continuous casting process, OCC copper exhibits a single-crystal structure where individual grains extend continuously across hundreds of meters. By virtually eliminating transverse grain boundaries and reducing purity defects to under 0.00002% (up to 99.99998% 6N purity), OCC copper wire provides an unhindered ballistic-like path for charge carriers.
Microstructural Advantages of OCC Wire
- Zero Transverse Grain Boundaries: Prevents signal distortion, localized thermal hot-spots, and inter-grain boundary micro-cracks.
- Conductivity > 101.5% IACS: Exceeds international annealed copper standards for optimal electrical throughput.
- Superior Ductility & Mechanical Stability: Withstands aggressive high-speed coil winding without insulation delamination or internal micro-fractures.
- Reduced AC Resistance: Reduces skin effect and proximity losses in high-frequency magnetics operated above 100 kHz.
Ultra-High Energy Conversion Efficiency
Minimizing I²R conduction losses within the winding allows magnetic components to maintain >99.2% operational efficiency, crucial for 800V EV architectures and SiC/GaN power modules.
Enhanced Thermal Dissipation
Single-crystal structure facilitates linear thermal phonon transport, lowering steady-state operating temperatures by 12°C to 20°C compared to conventional OFC copper windings.
High Dielectric Reliability
Paired with high-temperature enamels (AIW 220°C, PI tape, ETFE extrusion), OCC magnet wires ensure multi-year operational reliability under harsh partial discharge environments.
Industrial & Commercial Market Landscape for Advanced Power Conversion
The global electrification boom is pushing power conversion devices to work at higher switching frequencies and smaller form factors. Wide Bandgap (WBG) semiconductors, such as Silicon Carbide (SiC) MOSFETs and Gallium Nitride (GaN) HEMTs, allow switching speeds exceeding 500 kHz to several MHz. However, high-frequency operation introduces severe parasitic AC losses in traditional transformer windings.
As a response, tier-1 automotive suppliers, industrial automation manufacturers, and aerospace power system designers are transitioning toward OCC copper magnet wires, ultra-fine stranded Litz wires, and self-bonding rectangular wires. The industrial demand for OCC copper in power conversion device winding is surging in four primary sectors:
Key Commercial Drivers
1. Electric Vehicle On-Board Chargers (OBC) & DC-DC Converters: High-density 11kW and 22kW OBC units require compact planar transformers and resonant inductors wound with high-purity OCC Litz wire wrapped in high-dielectric ETFE or PI film.
2. Wireless Power Transfer (WPT) for EV & Consumer Electronics: High-Q factor transmitter and receiver coils rely on 6N OCC copper strands to minimize high-frequency AC skin resistance.
3. Renewable Energy Central & String Inverters: Mega-watt scale solar and wind inverters benefit from rectangular OCC copper magnet wire (such as AIW220) to maximize slot fill factor and manage thermals.
Deep Technical Analysis: Skin Effect & Core Loss Reduction
In high-frequency power conversion device windings, alternating current tends to concentrate on the outer skin of the conductor—a phenomenon known as the Skin Effect. Additionally, adjacent conductor strands induce eddy currents in one another, creating severe Proximity Effect losses.
Combining Ohno Continuous Cast (OCC) metallization with custom Litz wire construction effectively solves both problems. By bundling thousands of individually insulated micro-strands (e.g., 0.05mm or 0.06mm down to 0.025mm) made from 99.99998% single-crystal copper in a precisely engineered twisting pattern:
Without OCC Litz Winding
- High AC/DC resistance ratio ($R_{ac}/R_{dc} > 3.5$) at 300 kHz.
- Severe grain-boundary scattering causing thermal hotspots.
- Increased core operating temperature leading to thermal runaway.
- Bulky cooling systems required, reducing overall power density.
With Ruiyuan OCC Litz Technology
- Optimized $R_{ac}/R_{dc} \approx 1.05$ across target operating band.
- Uninterrupted electron flow due to single-crystal copper structure.
- Temperature reduction up to 25% under maximum continuous rating.
- Enables ultra-compact magnetics design meeting UL94-V0 & Class H/N thermal standards.
Company Profile
Tianjin Ruiyuan Electric Material Co,. Ltd. (Ruiyuan) was established in 2002. In the past 20 years, we have been thinking one question: "How to Satisfy Customers?" That drive has led us to expand product lines from fine enameled copper wire to litz wire, USTC, rectangular enameled copper wire, triple insulated wire, and also guitar pickup wire—spanning 6 main types with over 20 kinds of magnet wire. Here you will enjoy a One Stop Purchase Service with cost-effective prices, and quality is the last thing you need to concern. We wish to help you reduce your costs, save your time, and establish long-term Win-Win cooperation.
What we have been doing in 20 years is pursuing our operational philosophy: ‘Customer Oriented, Innovation Brings More Value’. That is not just a slogan, but a core part of our DNA. Unlike ordinary magnet wire providers who only offer standardized size ranges, we are a solution provider. We bring deep technical expertise in wires, insulation materials, and tailored solutions for high-frequency power conversion applications.
Innovation Case Study: EV Wireless Charging
One of our European automotive customers required a high-frequency litz wire for an EV wireless charging system. The wire needed exceptional solvent resistance and an extreme flame retardancy rate following UL94-V0. Standard insulation could not meet these requirements, and alternative commercial solutions were prohibitively expensive.
Finally, our specialized R&D team proposed an innovative solution: ETFE insulation directly extruded over the high-frequency litz wire surface. This approach perfectly solved every mechanical, thermal, and chemical barrier after one year of rigorous verification. The project completed a two-year qualification period and has been in mass production successfully.
Manufacturing & Quality Control Facility
SUCH CASES ARE PREVALENT IN OUR COMPANY, DEMONSTRATING OUR ADVANTAGES IN TECHNOLOGY AND SERVICE. THESE NUMBERS TELL MORE ABOUT US:
Exquisite, Quality, All For The Customer!
Ruiyuan attracts many outstanding technical and management talents. Our founders have built one of the best engineering teams in the industry with a focus on long-term technological vision. This is our guarantee to provide superior products and custom material solutions to all our global partners.
We really hope to know you, bringing more value with our high-purity OCC copper products, high-frequency Litz wire designs, and client-centric engineering service.
Frequently Asked Questions (FAQ)
High-Purity OCC & Magnet Wire Catalog for Device Winding
Explore our full line of specialized Litz wires, ETFE triple insulated wires, OCC copper pellets, and rectangular magnet wires engineered for extreme power conversion efficiency.
Explore What RUIYUAN Can Do For Your Power Conversion Devices
We sincerely welcome engineers, procurement directors, and technology pioneers from around the world to partner with us. Contact our engineering team today for technical consultation, material sampling, and custom winding specifications.
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