Vehicle charger and method for controlling the same

A vehicle charger comprising:

• an inductor having a first end connected to a first end of an alternating current (AC) power source;
• a first leg comprising a first switching element and a second switching element, which are connected to each other in series, wherein connection terminals of the first switching element and the second switching element are connected to a second end of the inductor;
• a capacitor connected to the first leg in parallel;
• a second leg comprising a third switching element and a fourth switching element, which are connected to each other in series between both ends of the capacitor, wherein connection terminals of the third switching element and the fourth switching element are connected to a second end of the AC power source;
• a transformer, which has a primary coil having a first end connected to the connection terminals of the third switching element and the fourth switching element, and a secondary coil electromagnetically coupled to the primary coil;
• a third leg comprising a fifth switching element and a sixth switching element, which are connected to each other in series between both ends of the capacitor, wherein connection terminals of the fifth switching element and the sixth switching element are connected to a second end of the primary coil;
• and
• a controller configured to control the first and second switching elements in order to adjust a voltage of the capacitor, and configured to control the third and fourth switching elements in order to convert a magnitude of the voltage of the capacitor,
• wherein the controller generates a detection voltage of the capacitor and a first reference voltage for making the detection voltage of the capacitor obey an externally input voltage command for the capacitor, and
• the first reference voltage has a form of an alternating current synchronized with an alternating current of the AC power source.