Low-inductance direct current power bus
A DC power bus having reduced parasitic inductance and higher tolerable operating temperature is disclosed. In example embodiments, a bus structure overlies a printed circuit board, and an array of capacitors is arranged on a surface of the printed circuit board distal the bus structure. The bus structure comprises an upper metal plate, a lower metal plate, and a dielectric film interposed between the upper and lower metal plates. The capacitors are connected in parallel between conductive planes of the printed circuit board. The upper and lower metal plates of the bus structure are connected to respective conductive planes of the printed circuit board.
1. A DC power bus, comprising:
an insulative base member having substantially planar upper and lower surfaces;
at least first and second electrically conductive metal layers laminated onto or within the insulative base member;
a bus structure that overlies the upper surface of the insulative base member; and
a plurality of capacitors mounted in a capacitor array on at least the lower surface of the insulative base member, wherein:
the bus structure comprises an upper metal plate, a lower metal plate, and a dielectric film interposed between the upper and lower metal plate;
each of said capacitors is electrically connected between the first and second laminated electrically conductive metal layers such that said capacitors are connected in parallel with each other; and
the upper and lower metal plates of the bus structure are respectively electrically connected to the first and second laminated electrically conductive metal layers.
2. The DC power bus of claim 1 , wherein:
the insulative base member is a printed circuit board;
first and second laminated electrically conductive metal layers are copper planes of the printed circuit board; and
the upper and lower metal plates of the bus structure are made of aluminum.
3. The DC power bus of claim 1 , wherein the said capacitors are multilayer ceramic capacitors.
4. The DC power bus of claim 1 , wherein the said capacitors are arranged in a regular one-dimensional array.
5. The DC power bus of claim 1 , wherein the said capacitors are arranged in a regular two-dimensional array.
6. The DC power bus of claim 1 , wherein upper metal plate of the bus structure is intermittently connected to the first laminated electrically conductive metal layer by vertical interconnections that pass through holes in the lower metal plate of the bus structure.
7. The DC power bus of claim 1 , configured with a resonant frequency greater than 100 kHz.
8. Apparatus comprising the DC power bus of claim 1 , wherein:
the DC power bus is connected to a power inverter, or to a DC-to-DC converter, or to a power inverter and to a DC-to-DC converter, and
the power inverter comprises one or more wide bandgap switching devices, or the DC-to-DC converter comprises one or more wide bandgap switching devices, or the power inverter and the DC-to-DC converter each comprise one or more wide bandgap switching devices.
9. The apparatus of claim 8 , wherein at least one said wide bandgap switching device is a silicon carbide power transistor.
10. The apparatus of claim 8 , wherein the power inverter operates at a switching frequency of at least 100 kHz, or the DC-to-DC converter operates at a switching frequency of at least 100 kHz, or the power inverter and the DC-to-DC converter each operate at a switching frequency of at least 100 kHz.
11. The apparatus of claim 8 , wherein no snubbing capacitors additional to the DC power bus capacitor array are connected across any wide-bandgap switching device.
12. A method, comprising:
delivering a flow of DC electric power from a producer to a consumer of power in an electric power system on a pair of parallel metal bus plates separated by a dielectric film; and
removing periodic components from the flow of DC electric power by filtering;
wherein:
the filtering comprises shunting the periodic components through a plurality of capacitors that are mounted in a capacitor array on the lower surface of an insulative base member and connected in parallel between first and second electrically conductive metal layers laminated onto or within the insulative base member; and
the shunting comprises conducting the periodic components through a plurality of electrical connections from each of the parallel metal bus plates to a respective one of the first and second laminated layers.
13. The method of claim 12 , wherein the capacitors of the capacitor array are multilayer ceramic capacitors.
14. The method of claim 12 , wherein the producer of power is a power inverter or a DC-to-DC converter, and the method further comprises operating the producer of power at a switching frequency of at least 100 kHz.
15. The method of claim 12 , performed at a steady-state temperature greater than 100° C.