System Description

BOOST CONVERTER CONTROL


System Description


GENERAL
- The boost converter boosts DC 244.8 V, the nominal voltage of the boost converter, up to a maximum voltage of DC 650 V, in accordance with the signals provided by the hybrid vehicle control ECU via the MG ECU.
- The inverter converts the alternating current generated by MG1 or MG2 into a direct current. The boost converter drops the maximum voltage of DC 650 V to DC 244.8 V, the nominal voltage of the boost converter, in accordance with the signals provided by the hybrid vehicle control ECU via the MG ECU.
- The boost converter consists of a boost IPM (Intelligent Power Module) with built-in IGBTs (Insulated Gate Bipolar Transistors) that effect switching control, and a reactor that stores (and charges) electrical power.

VOLTAGE BOOST CONVERSION FUNCTION
- The function of the boost converter to boost DC 244.8 V, the nominal voltage of the boost converter, to maximum voltage of DC 650 V flows as described below.
- The IGBT (2) turns ON, causing the electrical power of the HV battery to charge the reactor. As a result, the voltage in the reactor rises.





- In the next stage, when the voltage in the reactor rises to maximum voltage of DC 650 V, the IGBT (2) turns OFF, causing a counter electromotive force to be created.





- Induced by the counter electromotive force that is created, the electrical power (maximum voltage of DC 650 V) that is charging the reactor flows into the inverter.

VOLTAGE DROP CONVERSION FUNCTION
The alternating current, which is generated by MG1 or MG2 for the purpose of charging the HV battery, is converted into maximum voltage of DC 650 V by the inverter. Then, a function of the boost converter drops the voltage to DC 244.8 V, the nominal voltage of the boost converter. This is accomplished by the IGBT (1) switching ON and OFF through duty cycle control, which intermittently interrupts the electrical power provided by the inverter.