laminated busbar in High Power Converter: Selection Guide and Application Analysis

The laminated busbar is a composite conductive component used in high-voltage power converters. By alternately laminating multiple layers of conductive copper bars and insulating materials, a distribution path with low inductance, high capacitance, and large current carrying capacity is formed. In high power density application scenarios, laminated busbars can significantly reduce loop stray inductance, reduce switching overvoltage, and improve the reliability of power modules and system efficiency. In rail transit traction converters, the Composite Busbar for Train Power Supply Four-quadrant Power Module assumes the key task of efficiently connecting the rectifier and inverter units. Its laminated structure effectively suppresses voltage spikes in the four-quadrant operating mode and ensures the smooth operation of the train traction system. In the field of communication power distribution, Laminated Bus Bar for Telecom Power Distribution is integrated into the -48V DC power distribution system, replacing traditional wire harnesses with a compact stacked design, which not only reduces line losses, but also improves space utilization and heat dissipation in the cabinet. In the stage lighting control system, Laminated Bus Bar for PDA Assembly A Hit In Stage Lighting Systems relies on its high reliability and fast response current transmission capabilities to meet the stringent requirements for power distribution components of stage lighting equipment for frequent start, stop and dimming operations.

The material system of the laminated busbar mainly includes three parts: conductive layer material, insulating layer material and surface treatment material. The selection of materials directly determines the current carrying capacity, insulation performance, temperature resistance level and environmental adaptability of the product. The conductive layer material is usually made of high-conductivity copper (T2 or TU1 grade), whose conductivity is not less than 98% IACS, and the thickness range is generally 0.8mm to 6.0mm, which is selected according to the rated current. For rail transit applications such as Composite Busbar for Train Power Supply Four-quadrant Power Module, due to long-term exposure to vibration and impact environments, the elongation of copper materials is required to be greater than 30% to ensure that brittle fracture does not occur under mechanical stress.

For miniaturized products in Laminated Bus Bar for Compact IGBT DC Power, a composite conductive layer solution with aluminum core and copper plating is sometimes used to reduce weight while maintaining surface solderability. The insulation layer material generally uses flame-retardant polyester film (PET), polyimide film (PI) or epoxy glass cloth (FR-4). The polyimide film has excellent high temperature resistance and can work for a long time in the range of -40°C to +150°C. It is suitable for the wide temperature range working environment that may be faced in industrial vehicle applications such as DC and AC Laminated Bus Bar for Fork Lift Truck. For Laminated Bus Bar for Medical Imaging Testing Device, the insulation material also needs to meet low outgassing and radiation resistance properties to comply with medical device safety standards.

The manufacturing process of laminated busbars involves multiple links such as stamping, insulation lamination, thermal lamination, bending and surface treatment. The level of process control in each link directly determines the electrical performance and mechanical reliability of the product. In the stamping and forming process, the conductive copper bar is precision punched to form the outer contour and internal connection holes. The punched section should be smooth and burr-free. For the connector mating surface or the power module pin contact surface, the burr height must be controlled below 0.05mm to avoid poor contact or partial discharge. For large-size products such as Composite Busbar for Train Power Supply Four-quadrant Power Module, stress relief annealing is required after stamping to eliminate the internal stress generated during cold working and prevent warping during subsequent hot pressing. Insulation lamination is the core process of laminated busbars. According to the designed stacking sequence, conductive copper bars and insulating films are alternately stacked. The insulating films are usually pre-coated with hot melt adhesive on one or both sides to achieve bonding during the hot pressing process.

The stacking accuracy requires that the positioning deviation between each layer does not exceed ±0.1mm to ensure that the connection holes are accurately aligned between different copper layers. The hot-pressing process is carried out in a vacuum hot-pressing machine. The heating temperature, pressure and holding time need to be accurately set according to the thermosetting properties of the insulating film. For Laminated Bus Bar for Medical Imaging Testing Device, the hot-pressing process also needs to be carried out in a clean environment to prevent particle inclusions from causing a decrease in insulation withstand voltage. After hot pressing, the laminated busbar needs to undergo insulation withstand voltage testing and partial discharge testing to verify the integrity of the interlayer insulation. The bending forming process is used to process the flat laminated busbar into a three-dimensional shape that fits the installation space. The bending radius must be strictly controlled during bending to avoid the outer copper bar being too thin due to stretching or the inner copper bar being wrinkled due to compression. The insulation layer at the bend must not crack or peel.

The application of laminated busbars has long since transcended the single field of frequency converters, and has widely penetrated into various high-power scenarios:

In industrial frequency converters, the laminated bus bar for variable frequency drive connects the rectifier bridge, capacitors, and inverter module, ensuring efficient motor drive operation. For mining environments with extremely high explosion-proof requirements, the high-laminated busbar for voltage explosion-proof inverters provides indispensable safety assurance. In the field of new energy vehicles, the high thermal conductivity metallized film capacitor busbar for EV control systems is a core component of the motor controller, responsible for efficiently transferring battery energy to the inverter. Similarly, in rail transit, the inverter bus bar for rail traffic and the transportation locomotive power bus bar withstand enormous current surges and mechanical vibrations; their reliability directly affects the safe operation of trains.

With the explosive growth of computing power, the power density requirements for server power supplies are becoming increasingly stringent. Laminated busbars for supercomputer circuit boards or backplanes and for internet router backplanes, with their compact size and extremely low impedance, solve the heat dissipation and cabling challenges in high-density racks. Furthermore, laminated bus bars for cellular base station power distribution also play a crucial role in 5G deployment. In uninterruptible power supply (UPS) systems, the uninterruptible power supply system busbar ensures zero-latency and high reliability during power switching. In high-end medical equipment, laminated bus bars for medical imaging testing devices, with their low noise and high stability, guarantee image clarity.

Facing the stringent challenges of low inductance and high power density in high-power converters, we are committed to providing you with a comprehensive laminated busbar in High Power Converter, from structural optimization to thermal management. Please feel free to contact us for professional technical support.