Recently, hybrid electric vehicles are required high power with high fuel efficiency and comfortable large cabin space. An ultra compact intelligent power module for two-motor hybrid electric vehicles which integrates one back-boost chopper and an inverter for a traction motor, an inverter for a power generator has been developed. The module is the world's first released module which has a direct liquid cooling structure with a solder-joined aluminium heat sink. The module achieves a 30-% reduction of volume and a 60-% reduction of weight compared to our conventional models. A heat sink with high cooling capacity and a high-strength solder were newly developed to establish the structure. The module is designed for 700 V/ 400 kVA system and it has an on-chip self protection functions and serial communication interface with a master control unit.