The heat generated by the ETDS components and the harsh underhood conditions requires dedicated cooling systems to keep the components within acceptable temperatures. the heat exchanger with the power module's base plate and incorporated features to increase heat spreading and reduce package thermal resistance (figure 3). the design is compatible with single- and doublesided cooling configurations for power semiconductor thermal management. compared to the ls 600h double-sided cooled modules, dielevel heat flux improved by about a factor of two, and the package heat density improved by more than 30%. the designed heat exchanger also exceeded the performance of the ls 600h at the same fluid parasitic power. the improved power capability directly relates to improving the cost per power of the power electronics. moreover, the modular design of the heat exchanger is scalable and lends itself Reduction In Thermal Resistance Over Baseline Channel Flow (%) Lens Z100: ×100 (a) 300.00 µm to high-volume manufacturing processes for reduced cost. in another project, an aggressive jet-impingement-based cooling strategy was employed to enhance the thermal performance of a commercially available inverter system. the heat exchanger used submerged Weg jets impinging on microfinned surface structures (Wolverine microcool) to enhance heat transfer (figure 4). Prior work has demonstrated that the microfinned surfaces enhance heat transfer coefficients by more than 100% at higher jet velocities. that study inspired the development of an inverter-scale demonstration of this technology. a computational fluid dynamics analysis was conducted to design an inverter-scale heatexchanger system that impinged jets directly onto the power module's base plates. dynamometer experiments were carried out at the manufacturer's facility to measure the performance of the cooling system. at an inverter power of 100 kW, the jet-based heat exchanger reduced the thermal resistance by 17% while maintaining the same pumping power requirements of a baseline, Weg channelflow heat exchanger (figure 4). in addition to the thermal enhancements provided by the jets and enhanced surfaces, the jet-based heat exchanger was fabricated from a low-cost and lightweight plastic. in an effort to eliminate coolant loops and reduce system cost, there is interest in increasing component operating temperatures. a project led by delphi has developed a high-temperature inverter capable of being cooled with 20 15 10 5 0 40 60 80 Power (kW) (b) 100 Figure 4. Enhanced microfinned (Wolverine MicroCool) surfaces were used to enhance jet impingement heat transfer: (a) the Wolverine MicroCool surface and (b) the reduction in thermal resistance. Figure 5. A Delphi high-temperature inverter capable of operating with high-temperature (>100 °C) coolant. IEEE Electrific ation Magazine / j une 2 0 1 4 45