| 摘要 |
PURPOSE: A power supply unit and a controlling method thereof are provided to reduce the number of components and the manufacturing cost by improving a structure of the power supply unit. CONSTITUTION: A power supply unit includes a switching element, a diode, an inductance, a resistance, a first relay, and a controller. The switching element(4) is connected in parallel to a capacitor. The diode(5) includes a cathode connected to the capacitor and an anode connected to the switching element. The inductance(6) is arranged between the rectifier and a branch point of the switching element and the diode. The resistor(7) is connected in parallel to the diode. The first relay(8) includes a first contact for connecting the branch point to the resistor and a second contact for connecting the branch point to the inductance. The controller(11) is used for performing a control operation to connect the first relay to the second contact when a voltage between both ends of the capacitor exceeds a PFC limit voltage. |
