Patent ID: 7622873
Filing Date: 2009-11-24
Classification: H02P

Abstract:
1. A motor drive device operable to supply drive power to a motor by switching repeatedly between an urging state and a regeneration state, comprising: a drive signal generator operable to generate a drive signal; a driver having high potential side switching devices for N phases (where N is an integer greater than or equal to 2) and low potential side switching devices for N phases, said driver being operable to produce the drive power as a result that the high potential side switching devices for N phases and the low potential side switching devices for N phases are controlled by the drive signal; a reverse current detector connected in parallel to either the high potential side switching devices for N phases or the low potential side switching devices for N phases, said reverse current detector being operable to detect, based on the polarity of the on voltage of said switching devices connected to said reverse current detector, a time when the direction of motor current flowing through the motor reverses in the regeneration state and to generate a reverse current detection signal; a current detection unit operable to detect the motor current level of the motor and to output a current detection signal; and a torque control signal generator operable to generate a torque control signal setting the motor torque; wherein said drive signal generator controls the logic level of the drive signal based on this reverse current detection signal; and said drive signal generator controls the logic level of the drive signal based on the difference between the current detection signal and the torque control signal.