| 摘要 |
PROBLEM TO BE SOLVED: To prevent a rapid drop of current flowing in a coil of an electric motor. SOLUTION: The interval from an energization start for the coil to the energization stop is divided into three stages. In the first stage, soft/hard chopping conduction control is performed. In the second stage, 0 V chopping conduction control is performed, and in the third stage duty chopping conduction control is performed. The energization of the coil is performed through a first switching element and a second switching element. In the first stage, one/both of the first and second switching elements are turned off, according as a real current value exceeds a target current value. In the second stage, the second switching element is turned on turning the first switching element off. In the third stage, the second switching element is turned off, and on/off operation of the first switching element is repeated according to an arbitrary duty factor. |
