| 摘要 |
PROBLEM TO BE SOLVED: To detect a current at the time of DC brake and surely control an applied brake voltage by fixing the DC voltage applying pattern of DC brake and applying DC brake only at the time point, when the phase current of a current detector becomes positive maximum or negative maximum, and detecting the maximum current. SOLUTION: A DC control voltage is applied only at a point (b) or a point (e), in such a manner that the maximum current surely flowed in the U-phase where a current detector is set. The maximum current flowing at the point (b) or (e) is detected with the current detector, and the DC voltage applying pattern of an inverter is fixed. As a result, the maximum current at the time of DC brake can be surely detected. By feeding back the detected current to a control circuit, control of the applied brake voltage is enabled. |
