| 摘要 |
<P>PROBLEM TO BE SOLVED: To measure currents in each phase through a single current sensor for damping control and a motor brake of a three-phase electric power device. <P>SOLUTION: While a PWM-controlled FET switching three-phase motor 26 is operated at a mechanical damping mode, the current in the motor 26 is measured by using the signal current sensor 32. When a mechanical feedback to the motor 26 exceeds a specified threshold, one bank of FET switching devices (S1 to S6) is closed, and the damping for the mechanical feedback is provided. Therefore, the current circulates in the motor 26. To determine the time when the mechanical feedback to the motor 26 causes no problem, while the selected switching device is periodically switched, needed to sample the current in at least one phase of the motor 26, preferably an average zero voltage vector is maintained. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
