Uninterruptible power system, control apparatus of the same and method of controlling the same

A control apparatus for an uninterruptible power system operated in a line mode or a battery mode, the control apparatus comprising:

• a carrier controller for receiving a mains voltage and generating a base triangular wave signal and a switch triggering signal;
• and
• a pulse controller for receiving an alternating conversion voltage output from a power conversion apparatus and receiving the switch triggering signal, the pulse controller being configured to generate a pulse width modulation (PWM) signal for controlling the power conversion apparatus and generating a switch control signal for controlling a switch unit,
• wherein the control apparatus generates the base triangular wave signal according to the mains voltage in the line mode;
• wherein the control apparatus is configured to determine if a cross-over value of the base triangular wave signal is within a predetermined range at a zero-crossing point of the mains voltage when the uninterruptible power system is operated in the battery mode and the mains voltage resumes, and
• wherein the control apparatus is further configured to control the switch unit to output the mains voltage instead of the alternating conversion voltage when the cross-over value of the base triangular wave signal is within the predetermined range at the zero-crossing point of the mains voltage.

A method of controlling an uninterruptible power system, the method comprising:

• (a) providing the uninterruptible power system operable in a line mode or a battery mode;
• (b) receiving a mains voltage by the uninterruptible power system operating in the line mode;
• (c) generating a base triangular wave signal according to the mains voltage;
• (d) generating an alternating conversion voltage according to the mains voltage;
• (e) operating the uninterruptible power system in the battery mode and outputting the alternating conversion voltage;
• (f) receiving a resumed mains voltage by the uninterruptible power system;
• (g) determining if a cross-over value of the base triangular wave signal is within a predetermined range at a zero-crossing point of the resumed mains voltage;
• and
• (h) outputting the resumed mains voltage instead of the alternating conversion voltage when the cross-over value of the base triangular wave signal is within the predetermined range at zero-crossing point of the resumed mains voltage.