This paper deals with the system design, technology and test of a novel concept of integrating silicon power dies along with thermo-electric coolers and a phase change heat buffer in order to thermally manage transients occurring during operation. The innovative power-electronics concept features double-sided cooling as well as new materials and joining technologies to integrate the dies such as transient liquid phase bonding/soldering and sintering. To avoid a cold plate at the backside, a new low-cost, low-footprint thermal storage device has been developed and optimized by simulation to meet the requirements given by this application. Coupled-field simulations are used to predict thermal performance and are being verified by especially designed test stands.