US 5,311,105 AGranted

Brushless motor operating method and apparatus

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsMitsuhisa Nakai, Shiro Maeda, Toshiaki Yagi

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Abstract

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.

Claims6

Dependent claims

A method of operating a brushless motor which includes a rotor position detection means and which is operable in a rotor position detection operation mode and a synchronized operation mode,

said rotor position detection operation mode comprising:
detecting a voltage signal induced in an armature of a brushless motor having a magnet rotor;
and
operating said brushless motor in accordance with a commutation signal generated on the basis of a rotor position detection signal obtained through conversion of said voltage signal by said rotor position detection means;
said synchronized operation mode comprising:
forcibly operating said brushless motor by generating a rotating magnetic field in accordance with a commutation signal generated form an external signal source until said rotor position detection signal is settled, wherein said synchronized operation mode includes n kinds of driving waveform patterns and the first to n-th patterns are sequentially outputted with the outputting of the n-th pattern being following by cyclically outputting the patterns again in an identical sequence, thereby generating a rotating magnetic field in an armature winding of said brushless motor, said method comprising:
changing over, upon transition from the synchronized operation mode to the rotor position detection mode, a signal source for generation of said commutation signal from said external signal source to said rotor position detection signal after the (n-1)th pattern has been outputted and at a timing when the n-th pattern is to be subsequently outputted.

4 more elements

A brushless motor operating apparatus operable in a synchronized operation mode and a rotor position detection operation mode, comprising:

a brushless motor having a plural-phase armature winding connected in a neutral ungrounded fashion and a magnet rotor;
a DC power source;
a group of semiconductor switching elements for passing/interrupting a current to said armature winding;
position detection means for detecting a position of said armature winding and said magnet rotor in accordance with a voltage signal induced in said armature winding;
and
commutation signal generation means for outputting a synchronizing signal in said synchronized operation mode and generating a commutation signal on a basis of an output of said position detection means in said rotor position detection operation mode, whereby in said synchronized operation mode, said commutation signal generation means sequentially outputs n kinds of driving waveform patterns wherein the outputting of the n-th pattern is followed by cyclically outputting the patterns again in an identical sequence, thereby generating a rotating magnetic field in the armature winding, whereby upon transition from said synchronized operation mode to said rotor position detection operation mode, said commutation signal generation means changes over said commutation signal from said synchronizing signal to a signal based on said rotor position detection signal after the (n-1)th pattern has been outputted and at a timing when the n-th pattern is to be subsequently outputted.

3 more elements

Dependencies are inferred from the claim text.