Power device and a method for determining whether a load is present

A power device, comprising:

• an AC output terminal;
• a voltage sensor, electrically coupled to the AC output terminal;
• a current sensor, connected in series with the AC output terminal;
• and
• a control unit, electrically coupled to the voltage sensor and the current sensor, for obtaining, respectively through the voltage sensor and the current sensor, n instantaneous voltage values and n instantaneous current values from the AC output terminal during a first time period, wherein n is a natural number, the control unit being further used to calculate a voltage RMS value based on the n instantaneous voltage values, to calculate a current RMS value based on the n instantaneous current values, to calculate an apparent power value based on the voltage RMS value and the current RMS value, to calculate a real power value based on the n instantaneous voltage values and the n instantaneous current values, and to calculate a power factor value based on the apparent power value and the real power value, the control unit being further used to determine whether the power factor value is greater than a first threshold value to obtain a first determination result, and to determine that a load is electrically coupled to the AC output terminal when the first determination result is yes.