Abstract: An inverter type drive unit for feeding AC electric power of variable parameters to an electric motor comprises an electronic control section (40), a power converting and an output section comprising one or more identical power modules (11a-c), each forming a complete 3-phase output stage and arranged in a side-by-side disposition in a multiplying direction (A) and clamped by means of retaining devices (14a-c) to a cooling structure (10), wherein the power modules (11a-c) are connected in parallel to DC input terminals (25, 26) and to AC output terminals (32, 33, 34) via conductive sheets (20, 21, 27a-c), whereof the DC connected sheets (20, 21) cover substantially the entire physical surface area covered by the power modules (11a-c) so as to accomplish an even, simultaneous and low impedance DC current supply to all power modules (11a-c).

Abstract: A circuit arrangement comprises a circuit board (10), a semi-conductor (12) provided on a first side of the circuit board, and a heat sink (15) provided on a second side of the circuit board opposite to the first side and in heat transferring contact with the power semi-conductor. A heat conductive element (13) is provided in a hole (10a) in the circuit board, wherein the heat conductive element is positioned in heat transferring contact with both the semi-conductor and the heat sink for transfer of heat generated by the semi-conductor to the heat sink. A circuit arrangement is provided, wherein the provision of a low thermal resistance path through the circuit board by means of heat conductive elements provides a compact circuit arrangement well suited for assembly by means of an automated surface mounting process.