Much like how internal combustion engines and alternators work together on conventional vehicles, hybrid cars and electric motors use inverters and converters to manage power to and from the battery pack to the motors and other on-board systems.
Inverters transform direct current (DC) from the battery into alternating current (AC) to power the vehicle. Inverters also control the motor and convert it to a generator, transferring braking energy back into the battery.
Converters control the DC voltage from the battery, either stepping it up or down based on the system and the power needed. DC/DC converters usually step down the high voltage from the battery pack to the 12-volts used by radios, headlights, and more.