Development of Intelligent Power Module for Hybrid Electric Vehicle

Toyota developed the first-generation Intelligent Power Module (hereinafter referred to as IPM) that is the key part of the system for Hybrid Electric Vehicles (hereinafter referred to as HEV). It was installed in the inverter for Prius, which was launched in Japan in 1997, and recently, the demands for not only mileage performance but also power performance in an HEV have been increasing. For the inverter for Prius that was launched in 2003, we developed a new IPM for the high voltage and high power that is applied in the second generation Toyota Hybrid System (hereinafter referred to as THSII). In the second-generation IPM, the boost converter that raises the power-supply voltage was added in the inverter, and a low electric current in the IPM was achieved based on “Power = Voltage × Electric Current”. The IPM for the motor and the IPM for the generator were integrated by using the merits of the system. Additionally, as for the circuit portion, the power supply circuit and the current sensor that were different circuit portions originally, were integrated and consequently miniaturization of the IPM was realized. The second-generation 120kw-class IPM for RX400h, in addition to the 50kw-class IPM for Prius, was developed.