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US 4,503,369 AGranted
Power supply for plural brushless DC motors
AssigneeHitachi, Ltd.
InventorsHideo Nishijima, Isao Fukushima, Tsunehiko Teshima, Yasunori Kobori, Takayasu Ito
Life of this patent
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Abstract
A power supply in which a single variable voltage supply device is used as a power source for a plurality of motors which are simultaneously or successively rotated, in which each motor is subjected to constant current driving by a current control device connected to the motor, and in which the variable voltage supply device is controlled so as to produce a voltage which is the sum of the highest one of the voltages required for driving the motors and necessary and minimum voltage with which all the current control devices are operable.
Claims14
A power supply for a plurality of motors each including a plurality of motor driving coils, said power supply comprising:
- a variable voltage supply device for supplying a voltage to said plurality of driving coils of each of said plurality of motors;
- a plurality of motor driving units provided respectively correspondingly for said plurality of motors, each of said motor driving units being connected between said variable voltage supply device and said plurality of motor driving coils of an associated one of said motors so as to cause the associated motor to rotate under a predetermined rotational condition, each of at least two of said plurality of motor driving units including, (a) a plurality of current control devices respectively connected to said plurality of motor driving coils of the motor associated with the motor driving unit for controlling currents to be passed respectively through said motor driving coils, (b) a commutator device connected to said plurality of current control devices for controlling the conduction period and amplitude of each of the currents flowing through said current control devices, and (c) a detecting device for detecting a signal related to both a voltage value applied to said plurality of motor driving coils of the associated motor and a voltage value appearing at said current control devices connected to said motor driving coils;
- and
- a control signal generating device for selecting one of signals detected by the respective detecting devices of said at least two motor driving units, said selected one signal corresponding to the motor driving coils of one of said motors which requires the highest one of the voltages required by the plurality of motor driving coils of said respective motors, said control signal generating device producing a control signal on the basis of said selected one of said detected signals,
- said variable voltage supply device including a reference voltage means for providing a reference voltage, a comparator means for comparing a voltage of said control signal with said reference voltage, and a control means responsive to an output of said comparator means for controlling an output voltage of said variable voltage supply device.
2 more elements
A power supply for a plurality of motors comprising:
- a single variable voltage supply device, including an output voltage control loop, for supplying a voltage to said plurality of motors;
- a plurality of motor driving units respectively correspondingly connected in series with said plurality of motors for driving said motors, said voltage being applied to each of the series connections of said plurality of motors and motor driving units;
- at least two detecting devices respectively connected to at least two of said plurality of motor driving units, each for detecting a signal related to both a voltage value applied to the motor driven by the associated motor driving unit and a voltage value applied to said associated motor driving unit;
- and
- a control signal generating device responsive to the detected signals from said at least two detecting devices for producing a control signal corresponding to one of the at least two of said motors connected to said at least two motor driving units,
- said variable voltage supply device being controlled by said output voltage control loop in accordance with said control signal so as to produce a voltage which is the sum of a voltage applied to one of said at least two motors which requires a voltage higher than the other and the lowest limit voltage in the operative voltage region in which said at least two motor driving units are operable.
3 more elements
Dependencies are inferred from the claim text.