Low Inductance DC Power Bus

A low-inductance DC power bus for high frequency, high temperature operation in electric drive systems and next-generation power electronics

A new generation of power electronic conversion systems are being enabled by wide-bandgap (WBG) devices. Applications in civilian and defense sectors are already realizing improved power density and efficiency in power converters that utilize silicon carbide (SiC) and/or gallium nitride (GaN) switches. However, as semiconductor switches become capable of greater hold-off voltage, higher switching frequency, and higher junction temperature, limits on converter performance will depend on the balance of the system: device packaging, filter components, and thermal management as examples. To fully realize the benefits of WBG device in an inverter, the DC link capacitor must support high frequency switching, be co-located with the switches to mitigate parasitic inductance, and be capable of higher temperature operation (due to switch proximity). To this end, Sandia researchers have developed a low-inductance DC power bus for high frequency, high temperature operation in electric drive systems and next-generation power electronics.

The low-inductance DC power bus demonstrates substantial reductions in parasitic inductance over conventional DC link systems by using a printed circuit board and carefully controlled capacitor placement to maximize planar capacitance. Utilizing ceramic rather than standard electrolytic or film capacitors helps to achieve higher operating temperatures and improved thermal management. Parallel capacitor placement provides low shunt impedance to high-frequency current components and smooths current spikes created by switching operations. Beyond electric vehicle drive systems, this system may be relevant in electric drive applications where high-frequency switching and/or high temperature operations are desired.