In this paper, theoretical and experimental studies were conducted on the cooling performance of a microchannel heat dissipation device with a manifold layer added. By adding 500 μm wide microchannels and manifold flow fields, the rheological properties of the cooling fluid were enhanced to improve the heat transfer performance. The size of the microchannel used for cooling was 40 × 40 × 5 mm, and was evaluated under a heat flux of 12.5-43.75 W/㎠ and a flow rate of 0.3-1.1 L /min conditions. As a result of the experiment, in the case of a microchannel heat sink of 500 μm compared to the existing heat sink, cooling was successfully performed under a heat flux condition of about four times

Power electronic systems have been widely applied in both industrial and domestic applications in the modern society for controlling and converting electrical energy. Due to their characteristics, such as excellent performance, low cost, high reliability, and low weight and size, power semiconductors, including insulated-gate bipolar transistors (IGBTs) dominate the market of power converters. The technical progress and development trend of IGBT for industrial applications are primarily driven by five aspects influenced by each other to an extent, including operating temperature, efficiency, dimension, reliability, and cost. Liquid cooling systems surpass the air cooling systems by supplying heat transfer coefficient, which is several orders of magnitude higher. Thus, using liquid cooling system enables much higher power densities of power modules and more compact converter solutions.

The high voltage direct current (HVDC) device has been used to transmit electrical power with an advanced technology of semiconductors. The sustainable energy generation technologies of solar power and windmills are demanding that the HVDCs have high performance and reliability. In this regard, the cooling performance of the HVDC becomes a significant research topic because the temperature increase affects the operation of the device. The evaluation system to assess the cooling performance has been developed and is proposed in this paper. The experimental apparatus is presented in detail. Our experiments have shown the accuracy of flow rates, pressure drops, and the temperatures in the desired measurement points. We have successfully developed an evaluation system of the cooling performance of the HVDC device which has 2.48 kW of heat dissipation.