Brushless d-c motor
AssigneeFuji Electric Co., Ltd.
InventorToshitaka Nakajima
Life of this patent
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Abstract
A brushless d-c motor of the type having a permanent magnet rotor and a plurality of stator windings which are energized from a common d-c power source through transistors in response to means which detect the rotating position of the rotor in a manner such that the conductance of the transistors are so controlled as to ensure proper rotation, in which, means are provided for detecting the currents flowing through the stator windings and the outputs of these means used to control the transistors supplying current to the stators such as to equalize the current flow from stator winding to stator winding, thereby permitting transistors having unmatched gains to be used in the motor.
Claims8
In a brushless d-c motor having a permenant magnet rotor and a plurality of stator windings with at least two of the stator windings having a lead in common and further including means to successively energize the stator windings using commutation transistors, in dependence of the angular position of the rotor, the improvement comprising:
- a. a resistor coupling two stator windings in common to a voltage terminal to develop a voltage output representing the current flowing in the stator windings with which it is associated;
- and
- b. means having said voltage output as an input and providing an output coupled to control the commutation transistors associated with said two stator windings having a common lead so as to regulate the current flowing through said transistors to maintain currents of approximately equal magnitude flowing in each of the two stator windings having a common lead.
Dependencies are inferred from the claim text.