| 摘要 |
In a current detection system for detecting phase currents of an electric motor driven through a power converter adapted for carrying out ON/OFF control of bridge-connected plural switching elements in accordance with a predetermined excitation pattern to convert direct current into, e.g., three phase alternating currents, there are provided a current detecting element connected to the direct current side of the power converter and serving to provide a signal corresponding to current value, a waveform changer for changing the predetermined excitation pattern so that a signal directly or indirectly corresponding to the phase currents is produced at the current detecting element, and a current detector for detecting phase currents of the electric motor on the basis of the signal produced at the current detecting element and the changed excitation pattern. As a result, detections of phase currents of the electric motor can be carried out by using single current detecting element. Thus, vector control of the electric motor using such current detection system can be realized.
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