Electrically isolated power switching device mounting assembly for emi reduction

Abstract

A power electronics chassis (,) and liquid-cooled heat sink mounting assembly for electric vehicles and other applications that use liquid coolant to cool power electronic devices (,) contained within an electrically conductive housing (,). The power electronics chassis (,) includes an inverter (,) containing power switching devices (,) that are heat sunk using the liquid-cooled mounting assembly. The mounting assembly includes a heat exchanger (,) and a plastic, electrically non-conductive coolant manifold (,) that has an inlet (,) and outlet (,) for passage of liquid coolant into and out of the electronics housing (,). The power switching devices (,) are attached to a mounting surface (,) of the heat exchanger (,) and are thermally coupled to the coolant within the heat exchanger (,) via the mounting surface (,). The inlet (,) and outlet (,) of the plastic coolant manifold (,) are connected to the heat exchanger (,) by conduits (,) to thereby permit circulation of liquid coolant into the chassis housing (,), through the heat exchanger (,), and back out of the chassis housing (,) while maintaining electrical isolation between the liquid coolant and chassis housing (,). This configuration significantly reduces the radiated EMI by significantly reducing the parasitic capacitance between the switching devices (,) and chassis housing (,).