| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor control device capable of detecting a rotation position of a rotor with stability by a position sensorless system without increasing a ripple current.SOLUTION: A ripple current calculation circuit 12 of a microcomputer 5 estimates a magnitude of a ripple current Ir, for a current flowing in a power line 4b of an inverter circuit 6. When the magnitude of the ripple current Ir is equal to or less than a threshold, a switching control circuit 14 performs balanced drive switching of repeating a pattern in which one of output terminals corresponding to two energization phases of the inverter circuit 6 is made alternately conductive to a positive side terminal and a negative side terminal of a DC power supply 2, and the other of the output terminals is made alternately conductive to the negative side terminal and the positive side terminal. In addition, when the magnitude of the ripple current Ir becomes larger than the threshold, the switching control circuit 14 performs imbalanced drive switching of making one of the output terminals alternately conductive to a high voltage side and a low voltage side and making the other of the output terminals conductive only to the negative side terminal. |
