Semikron SKKD380/18 | High-Reliability Rectifier Diode Module for Power Conversion
The Semikron SKKD380/18 is a robust, high-current rectifier diode module engineered for demanding power conversion applications. Housed in the industry-standard SEMIPACK® 3 package, this module provides a dependable solution for designers building high-power front-end rectifiers, DC power supplies, and motor control systems. Its core value lies in its combination of high voltage and current ratings with exceptional operational reliability, a hallmark of Semikron engineering.
Product Highlights Overview
Engineered for performance and longevity, the SKKD380/18 delivers tangible benefits for system designers:
- High Power Density: With a forward current rating of 380 A and a repetitive peak reverse voltage of 1800 V, this module is ideally suited for high-power industrial systems.
- Robust Construction: Features glass passivated diode chips, which ensure stable blocking characteristics and long-term reliability even under harsh operating conditions.
- Simplified Thermal Design: The module incorporates an electrically insulated baseplate made from Aluminium Oxide (Al2O3) ceramic, simplifying heatsink mounting and improving overall thermal performance.
- Versatile Topology: The series connection of two diodes (common cathode configuration) makes it perfect for single-phase and three-phase uncontrolled or half-controlled bridge rectifier circuits.
Key Parameters at a Glance
The following table outlines the critical electrical and thermal specifications that engineers rely on for system design and simulation. For a comprehensive list of characteristics and performance curves, you can Download the SKKD380/18 Datasheet.
| Parameter | Value |
|---|---|
| Repetitive Peak Reverse Voltage (VRRM) | 1800 V |
| Forward Current (IFAV) @ Tcase = 86 °C | 380 A |
| Surge Forward Current (IFSM) @ 10 ms | 8500 A |
| Forward Voltage (VF) @ IF = 1200 A, Tj = 25 °C | 1.5 V (max) |
| Thermal Resistance, Junction to Case (Rth(j-c)) | 0.090 K/W (per diode) |
| Isolation Voltage (Visol) | 3000 V~ |
| Operating Junction Temperature (Tj) | -40 to 140 °C |
Application Scenarios & Value Proposition
The Semikron SKKD380/18 is not just a component; it's a solution for enhancing system reliability and performance in several key areas:
- Industrial Motor Drives: In the front-end AC-DC stage of Variable Frequency Drives (VFDs), this module provides the rugged rectification needed to handle high inrush currents and line voltage fluctuations, ensuring a stable DC bus for the inverter section.
- Welding Power Supplies: The high surge current capability (IFSM) of 8500 A is critical for welding applications, where the power source must endure intermittent short-circuit conditions without failure.
- Uninterruptible Power Supplies (UPS): Its robust voltage blocking (1800V) and proven reliability make the SKKD380/18 an excellent choice for the input rectifier in large-scale online UPS systems, guaranteeing continuous, clean power.
- Battery Charging Systems: For high-capacity industrial battery chargers, this module offers an efficient and thermally manageable rectification stage, capable of handling the continuous high currents required for fast charging cycles.
Technical Deep Dive: The Engineering Inside
Two core features set the Semikron SKKD380/18 apart. First, the use of glass passivated diode chips is fundamental to its long-term stability. Passivation protects the sensitive PN junction from ambient contaminants and electrical fields, preventing degradation of the reverse blocking voltage over the product's lifetime. This is a crucial factor for applications requiring high uptime and low maintenance.
Second, the electrically insulated baseplate provides a significant practical advantage. By using a high-quality Al2O3 ceramic insulator, Semikron eliminates the need for external insulating materials like thermal pads or mica washers between the module and the heatsink. This not only reduces assembly complexity and cost but also lowers the overall Thermal Resistance, leading to more efficient heat dissipation and a lower operating junction temperature for the diodes.
Frequently Asked Questions (FAQ)
1. How does the SKKD380/18 function within a power system that also uses IGBTs?
The SKKD380/18, as a rectifier diode module, typically operates at the "front end" of a power converter, converting incoming AC voltage to a DC voltage. This stable DC voltage then supplies the "DC bus." High-frequency switches, such as IGBT modules, are used in the subsequent inverter stage to chop this DC voltage and create a variable frequency/voltage AC output, for example, to control a motor's speed. They are complementary components in the power conversion chain.
2. Can these modules be connected in parallel for higher current applications?
Yes, but with careful consideration. When paralleling diode modules, it is critical to ensure proper current sharing. This is achieved by matching the forward voltage drop (VF) of the modules as closely as possible and by ensuring symmetrical layout of the busbars to equalize stray inductances. For designs requiring currents significantly higher than what a single module can handle, it is often better to select a larger, single module or to contact our technical team for application support on paralleling strategies.
