DENSO developed a new high output density power card and a more efficient cooling structure. Compared with its installation in the previous Prius model, application of this advanced power control unit helps to reduce electric power loss by more than 20%.
The PCU consists of inverter for generator/motor, boost converter and DC/DC converter.
In the 4th generation PCU, the functions of current sensor have increased for speedup of boost converter control. The PCU can now detect input current of boost converter and output current of motor/generator inverter. This enables the PCU to reduce variation of system high-voltage. With reduced variability of high-voltage, the capacitance of the inverter capacitor can be reduced.
The Power Card is the resin-molded package including IGBT (Insulated Gate Bipolar Transistor), FWD (Free Wheeling Diode), heat sink, and terminals.