Patent ID: 7944089

Claim:
An uninterruptible power supply module being coupled to an alternating-current voltage source to receive an input alternating-current voltage provided by the alternating-current voltage source, and providing an output alternating-current voltage to a load, the uninterruptible power supply module comprising: a direct-current voltage source, being configured to provide a direct-current voltage; a control module, being coupled to the alternating-current voltage source, and being configured to detect a voltage value of the input alternating-current and to generate a control signal in response to the voltage value; an inductive element, being coupled to the alternating-current voltage source and the direct-current voltage source, and configured to receive one of the direct-current voltage and the input alternating-current voltage; a control arm-bridge module, being coupled to the inductive element and the load, and configured to modulate one of the direct-current voltage and the input alternating-current voltage as the output alternating-current voltage transmitted to the load; a power source selection switch, being coupled to the inductive element, the power source selection switch comprising an alternating-current input terminal and a direct-current input terminal, the alternating-current input terminal being coupled to the alternating-current voltage source, the direct-current input terminal being coupled to the direct-current voltage source, the power source selection switch enabling the inductive element to connect to one of the alternating-current input terminal and the direct-current input terminal in response to the control signal; and a switch element, being coupled to the direct-current voltage source and the control arm-bridge module, making the power source selection switch performing a turn-on process involving a zero current state by means of switching between the alternating-current input terminal and the direct-current input terminal so as to obviate a current bounce.