The power control unit (PCU) controls the power-generation and drive motors in hybrid vehicles and electric vehicles during start off, acceleration, and deceleration.
It serves as a motor controller during start off, a regenerative controller during deceleration, a power generation controller when the battery is charging, and a VCU (Voltage Control Unit) controller for variable system voltage. It also uses a DC-DC converter to act as a voltage transformer for sources used to power on-board electrical equipment.
The new IPM has a printed circuit board equipped with an electric control unit (ECU) and gate drive circuits, 7 current sensors, and a power module with RC-IGBTs (Reverse Conducting-Insulated Gate Bipolar Transistor). A new VCU control sequence suppresses the fluctuation in high DC line voltage, while a cooling structure that covers the surrounding of a high voltage capacitor reduces the capacitor temperature.
The main circuit of the GEN3S PCU is comprised of the inverters for the motor and generator as well as the voltage control unit (VCU; composed of reactor, condenser, and semiconductor power device). The GEN3S PCU also features a gate drive circuit and a control circuit for controlling the main circuit, current sensors for detecting the 3-phase output and current at the VCU circuit and the voltage sensors for high-voltage portions, and the DC-DC converter for auxiliary devices. In addition, a temperature sensor and on-chip current sensor are installed in the semiconductor power device.
The newly developed technologies and components dramatically decreased the number and volume of parts in the PCU. Thus, a new PCU with small size and low cost was realized.