Comparison between laminated busbar and traditional busbar
In the main circuit, because the switching devices and the parasitic inductance of the DC-side capacitor cannot generally be changed, the most fundamental measure to suppress the switching voltage spike is to reduce the distributed inductance of the main loop bus.
As the electrical connection between the DC-side supporting capacitor and the switching device, there are generally the following four forms:
1) Copper bars or copper plates arranged in parallel. It is characterized by simple manufacture and easy implementation, and has certain effect on the suppression of voltage spikes, but the mutual inductance is still very large, which is suitable for occasions with large power but low performance requirements.
2) Cable strands. Its characteristics are cheap and easy to use, but the cable has great self-inductance and mutual inductance, poor performance, and low current carrying capacity. It is suitable for occasions with low performance requirements and low power.
3) Coaxial cable. Its characteristics are easy to use, and the mutual inductance of the coaxial cable is not large, but the price is more expensive, the current carrying capacity is not large, and it is suitable for low power occasions with general performance requirements.
4) Laminated busbars. Its structure is that two or more layers of copper are stacked together, and the copper plate layers are electrically insulated with insulating materials, and the conductive layer and the insulation are laminated into a whole through related processes. Its advantage is that the connecting wire is made into a flat cross section, the surface area of the conductive layer is increased under the same current cross section, and the interval between the conductive layers is greatly reduced. Due to the proximity effect, the adjacent conductive layers flow through the opposite Current, the magnetic field they produce cancel each other, so that the distributed inductance in the line is greatly reduced. In addition, due to its flat shape, its heat dissipation area has increased significantly, which has
Conducive to the improvement of its current carrying capacity.