Power control method and device

An apparatus for power control configured to control reactive power of a power converter converting power produced by a generator, the apparatus comprising:

• a voltage comparing part configured to compute an error voltage by using a measured voltage measured at the generator and a reference voltage that is designated;
• a control module configured to compute a first reactive power value for power control of the generator by being inputted with the error voltage;
• and
• a driving module configured to compute a reference reactive power value by using the first reactive power value and a second reactive power value computed using an active power value of the power converter and configured to control the power converter in correspondence with the computed reference reactive power value,
• wherein the reference reactive power is computed by Formula 1, the reference reactive power value being a surplus of reactive power in preparation for active power of the power converter
• Qset=min Qt, Qp <Formula 1>
• whereas the Qset is the reference reactive power value, and the Qp is the first reactive power value, and the Qt is the second reactive power value,
• wherein the second reactive power value is computed by Formula 2
• Qt=max((P/PF)2−P2)1/2, (1−P2)1/2 <Formula 2>
• whereas the P is an active power value of the power converter, and the PF is a power factor of the power converter.