| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to easily control the quantity of DC offset by compensation, by providing means of determining an estimate of disturbance by operation. SOLUTION: When operating an estimate of disturbance, the same effect as inserting a filter of particular frequency characteristics to this power control system can be obtained, and a DC component of a main circuit (control system) containing a transformer 3 is restricted and also the drift excitation of a transformer 3 is restricted. In short, the frequency characteristics lower than 0 dB at DC and its vicinity in a current control system means that the DC component is hard to flow into a control target including a transformer 3, and the drift excitation of a transformer 3 is prevented. In this way, if the DC component can be restricted by a current controller, then the drift excitation can be prevented even though the DC offset has not been adjusted strictly to zero at current detectors 7u, 7w, 10w and A/D converters 8, 11 and so forth. |
