Brushless motor operating method and apparatus

摘要

In a brushless motor, during a synchronized operation mode, n kinds of driving waveforms having the first to n-th patterns are sequentially outputted and the outputting of the n-th pattern is followed by cyclically outputting the patterns again in a sequence from the first pattern, thereby generating a rotating magnetic field in an armature winding. Upon transition from the synchronized operation mode to a rotor position detection operation mode, the commutation signal is changed over from the synchronizing signal to a signal based on the rotor position detector signal after the (n-1)th pattern has been outputted and at a timing when the n-th pattern is to be subsequently outputted. Thereby, upon transition from the synchronized operation mode to the rotor position detection operation mode, the commutation signals are linked in a proper sequence so that smooth mode transition becomes possible without the addition of any special ancillary circuit.