Patent ID: 7626350
Filing Date: 2009-12-01
Classification: H02P

Abstract:
1. A motor drive apparatus for driving an N phase (where N is an integer of 2 or more) motor by an N phase PWM drive signal, comprising: a speed detection unit operable to detect the rotor speed of said N phase motor and outputting a speed signal containing a frequency component related to said rotor speed; a drive control signal generator operable to generate a first voltage drive control signal and a second voltage drive control signal; a drive signal generator operable to generate said PWM drive signal based on said first voltage drive control signal; a drive output unit operable to supply power to said N phase motor based on said PWM drive signal; a current phase detection unit operable to detect a zero cross phase of a motor current flowing to said N phase motor; and a phase difference generator operable to detect a phase difference between the zero cross phase of said motor current and the phase of said second voltage drive control signal to generate a phase difference signal; wherein said drive control signal generator comprises: