Dual air and liquid cooling media compatible electric machine electronics

An electronic package adapted for connection to a rear frame member of an electric machine of liquid-cooled and/or air-cooled type, the electronic package comprising:

• a cooling tower having opposite first and second axial ends spaced along a package central axis, the cooling tower comprising a metallic wall extending about the package central axis to define a radially outer wall surface, wherein the cooling tower is at ground potential and defines a heat sink;
• and
• a plurality of power modules mounted in conductive thermal communication to the cooling tower at circumferentially distributed positions on the radially outer wall surface, each power module comprising:
• a thermally and electrically conductive base having opposite first and second surfaces, the first surface adapted for mounting the power module in conductive thermal communication with a heat sink at ground potential, and
• a pair of positive and negative MOSFET devices superposing the base second surface, wherein the MOSFET devices of the pair are both in conductive thermal communication with the base, and
• wherein transference from the power module of heat generated by the MOSFET devices occurs along a primary cooling path from the power module to the heat sink through the base;
• wherein heat transference to the cooling tower from each power module occurs along the respective primary cooling path, and wherein transference along the primary cooling paths of heat from the cooling tower includes thermal convection to air and/or liquid;
• wherein the cooling tower metallic wall defines a radially inner wall surface, the radially inner wall surface defining an axially extending air passage through the cooling tower, the air passage having an inlet proximate the first axial end,
• wherein the cooling tower comprises a plurality of spaced metallic ribs in conductive thermal communication with the radially inner wall surface, the ribs traversing the air passage, and
• wherein the primary cooling path respective to each power module extends radially inwardly to the cooling tower therefrom.

An electric machine comprising a stator defining a machine central axis, a rotor surrounded by and rotatable relative to the stator about the machine central axis, a rear frame member rotatably fixed relative to the stator and through which the machine central axis extends, and an electronic package, the electronic package comprising:

• a cooling tower having opposite first and second axial ends spaced along a package central axis, the cooling tower comprising a metallic wall extending about the package central axis to define a radially outer wall surface, wherein the cooling tower is at ground potential and defines a heat sink;
• and
• a plurality of power modules mounted in conductive thermal communication to the cooling tower at circumferentially distributed positions on the radially outer wall surface, each power module comprising:
• a thermally and electrically conductive base having opposite first and second surfaces, the first surface adapted for mounting the power module in conductive thermal communication with a heat sink at ground potential, and
• a pair of positive and negative MOSFET devices superposing the base second surface, wherein the MOSFET devices of the pair are both in conductive thermal communication with the base, and
• wherein transference from the power module of heat generated by the MOSFET devices occurs along a primary cooling path from the power module to the heat sink through the base;
• wherein heat transference to the cooling tower from each power module occurs along the respective primary cooling path, and wherein transference along the primary cooling paths of heat from the cooling tower includes thermal convection to air and/or liquid;
• wherein the machine central axis extends through the electronic package and the cooling tower is connected to the rear frame member, the rear frame member is at ground potential, and the cooling tower is electrically grounded through the rear frame of the electric machine;
• wherein the electric machine is air-cooled and the rear frame member has an aperture through which cooling air flow is drawn generally axially, in the direction of the rotor relative to the electronic package, for cooling the electric machine at locations downstream of the aperture,
• wherein the air passage has an outlet proximate the second axial end, and the air passage outlet is in fluid communication with the rear frame member aperture, and
• wherein cooling air flow is drawn into the air passage inlet and through the air passage, forced convective heat transfer along the primary cooling paths occurs between the cooling tower wall and ribs and the cooling air flow along the air passage, and the cooling air flow proceeds through the air passage outlet and the rear frame member aperture for cooling the electric machine at locations downstream of the aperture.

An electric machine comprising a stator defining a machine central axis, a rotor surrounded by and rotatable relative to the stator about the machine central axis, a rear frame member rotatably fixed relative to the stator and through which the machine central axis extends, and an electronic package, the electronic package comprising:

• a cooling tower having opposite first and second axial ends spaced along a package central axis, the cooling tower comprising a metallic wall extending about the package central axis to define a radially outer wall surface, wherein the cooling tower is at ground potential and defines a heat sink;
• and
• a plurality of power modules mounted in conductive thermal communication to the cooling tower at circumferentially distributed positions on the radially outer wall surface, each power module comprising:
• a thermally and electrically conductive base having opposite first and second surfaces, the first surface adapted for mounting the power module in conductive thermal communication with a heat sink at ground potential, and
• a pair of positive and negative MOSFET devices superposing the base second surface, wherein the MOSFET devices of the pair are both in conductive thermal communication with the base, and
• wherein transference from the power module of heat generated by the MOSFET devices occurs along a primary cooling path from the power module to the heat sink through the base;
• wherein heat transference to the cooling tower from each power module occurs along the respective primary cooling path, and wherein transference along the primary cooling paths of heat from the cooling tower includes thermal convection to air and/or liquid;
• wherein the machine central axis extends through the electronic package and the cooling tower is connected to the rear frame member, the rear frame member is at ground potential, and the cooling tower is electrically grounded through the rear frame of the electric machine;
• wherein the electric machine is liquid-cooled and the rear frame member defines a metallic wall extending substantially perpendicularly relative to the machine central axis, the rear frame member wall having an inner axial side in contact with liquid coolant and an opposite outer axial side in conductive thermal communication with the cooling tower, and
• wherein along the primary cooling paths conductive heat transfer occurs between the cooling tower and the rear frame member wall, and convective heat transfer occurs between the rear frame member wall and the liquid coolant.