Dual busbar linkage connection

A dual busbar linkage connection involves mechanically and electrically joining two busbars to share current efficiently, reduce inductance, and improve system reliability.

Overview

Dual busbar linkage is commonly used in high-current power systems to increase current capacity, improve current sharing, and reduce stray inductance. This is particularly important in DC bus systems, power converters, and parallel IGBT module configurations where uneven current distribution can lead to overheating or premature failure.

Connection Methods

Bolted Joints: Busbars are overlapped and secured with bolts and washers. This method is reliable and allows field assembly, but requires drilled holes and may introduce slight distortion in current paths. Clamped Joints: Overlapping busbars are held together with external clamps, providing nearly uniform contact pressure without drilling.

This reduces electrical resistance and thermal hotspots, though it requires more space. Riveted Joints: Similar to bolted joints but use rivets. They are permanent and cannot loosen, but controlling contact pressure is more challenging.

Laminated Busbars: Multiple layers of copper separated by dielectric material are laminated into a single structure. Laminated busbars reduce inductance, improve current sharing, and provide mechanical stability. They are ideal for parallel IGBT modules and high-frequency applications.

Design Considerations

Current Sharing: In dual busbar systems, symmetry and layer arrangement are critical to ensure even current distribution across parallel paths. Inductance Reduction: Laminated or closely spaced busbars minimize stray inductance, which is essential for high-speed switching in converters. Thermal Management: Proper spacing, clamping, and lamination help dissipate heat and prevent hotspots.

Mechanical Integrity: Connections must withstand vibration, thermal expansion, and mechanical stress while maintaining low electrical resistance.

Advanced Applications

Differential Current Sensing: Dual busbars can be used with differential Hall-effect sensors (e.g., DRV425) to measure current accurately while rejecting external magnetic interference.

Parallel IGB

T Modules: Multi-layer laminated busbars allow series-parallel connections of IGBT modules, improving power density and reliability in converters.

Summary

A dual busbar linkage connection is a critical design element in high-current and high-frequency power systems. Choosing the appropriate connection method—bolted, clamped, riveted, or laminated—depends on current capacity, mechanical constraints, thermal management, and electrical performance requirements. Laminated busbars are particularly effective for parallel module applications, offering low inductance, uniform current sharing, and structural integrity.