On-board charger for charging eco-friendly vehicle battery
An on-board charger for charging a battery of an eco-friendly vehicle and a method for charging a battery using the on-board charger are provided. The on board charger reduces an output current ripple by improving a snubber circuit unit of the on-board charger for charging a battery in plug-in hybrid and electric vehicles. In addition, the on-board charger for charging a battery of an eco-friendly vehicle reduces a surge voltage generated in a rectifier diode and reduces an output current ripple by arranging two capacitors and three diodes in a transformer secondary rectifier of the on-board charger.
1. An on board charger for charging a battery of a vehicle, comprising:
a full bridge input unit connected to a power factor compensator connected to an alternating current (AC) normal power supply to convert a direct current (DC) voltage into an AC voltage;
a main transformer that boosts the AC voltage from the full bridge input unit;
a rectifier diode that converts the AC voltage boosted by the main transformer into a DC voltage;
a snubber circuit unit that removes a surged high voltage generated upon turning off the rectifier diode;
an output inductor that converts an output voltage into a DC voltage with a ripple reduced together with an output capacitor; and
the output capacitor that converts the output voltage into the DC voltage with the ripple reduced together with the output inductor,
wherein the snubber circuit unit includes:
a first capacitor and a second capacitor connected to an output terminal of the rectifier diode to charge a surge voltage from the rectifier diode; and
a first diode, a second diode, and a third diode connected while forming a closed looped with the first capacitor and the second capacitor to form a closed loop discharge path of surge voltages discharged from the first capacitor and the second capacitor.
2. The on-board charger of claim 1 , wherein one end of the first capacitor is connected to an anode of the first diode and a cathode of the third diode, and one end of the second capacitor is connected to a cathode of the first diode and an anode of the second diode connected to one end of the inductor connected to an cathode thereof and the other end of the second capacitor is connected to an anode of the third diode.
3. A method for charging a battery using an on-board charger, comprising:
applying an alternating current (AC) power to the on-board charger installed within a vehicle;
generating a charging current by converting the AC power into direct current (DC) power; and
applying the charging current generated in the on-board charger to a high voltage battery for charging,
wherein the on board charger includes a snubber circuit unit having a first capacitor and a second capacitor connected to an output terminal of a rectifier diode to charge a surge voltage form the rectifier diode and a first diode, a second diode, and a third diode connected while forming a closed loop with the first capacitor and the second capacitor to form a closed loop discharge path of surge voltages discharged from the first capacitor and the second capacitor.
4. The method of claim 3 , wherein one end of the first capacitor is connected to an anode of the first diode and a cathode of the third diode, and one end of the second capacitor is connected to a cathode of the first diode and an anode of the second diode connected to one end of the inductor connected to an cathode thereof and the other end of the second capacitor is connected to an anode of the third diode.