Higher levels of integration for improved functionality along with increased power density are important for electronics in future vehicle platforms, where greater efficiency and reduced volume are critical. Power switching device (e.g. IGBT, MOSFET), driver board and cooling equipment are three important components of an automotive power electronic system. In the current work, a concept to integrate power modules, driver PCB and cold plate for extremely high-power density is proposed. A compact (10 mm thick) and high-performance cold plate was designed with a heat transfer coefficient higher than 30,000 W/(m²K) and a pressure drop penalty less than 2 psi at 10L/min flow rate (50-50 water-ethylene glycol). Six power devices bonded to DBC substrates together with FR-4 frame are bonded to the cold plate. Driver PCB is then 3D printed on top to connect all the power devices to an inverter. PCB layout was designed, and numerical model was developed to evaluate the integrated power device temperature due to power loss and PCB copper layer temperature distribution due to joule heating of the PCB circuitry. With the current compact and high-performance cold plate design and integration method via 3D printing, an extremely high 400 kW/L power density was reached for an automotive inverter compared to DOE 100 kW/L inverter target for 2025.