You have an electric vehicle and want to charge the battery from an AC grid voltage. An on-board charger (OBC) of an electric vehicle converts AC grid voltage into DC voltage to charge the high-voltage battery.

Operating Principle:

AC Input

• The grid provides a sinusoidal AC voltage that alternates between positive and negative values.

Rectification (Full-Bridge)

• A full-bridge rectifier uses four diodes. During each half-cycle, two diodes conduct, ensuring that current always flows in the same direction through the load.

Pulsating DC Output

• The output voltage is always positive but contains significant ripple at twice the grid frequency (100 Hz).

Smoothing

• A capacitor connected in parallel to the load reduces voltage ripple by storing and releasing energy.

Active Rectification (PFC)

• In real EV chargers, active rectifiers improve efficiency and power factor by shaping the input current to follow the voltage waveform.