Load torque detection and drive current optimization determination met
AssigneeSeiberco Incorporated
InventorMasayuki Someya
Life of this patent
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Abstract
The voltage at a node between a pair of series-connected windings of a synchronous or stepping motor is monitored during operation so as to detect transition voltage regions, the durations of which are indicative of the torque load on the motor and which are used as the basis for controlling the driving current amplitude so as to achieve enhanced efficiency of energy utilization. An optimum value for the duration of the transition voltage region will usually be established as a target, and adjustments will be so made as to conform subsequently detected node voltage values to those of the target.
Claims27
A method for controlling operation of a stepping motor having a multiplicity of series-connected windings arranged in ring configuration and driven by a square waveform voltage, comprising the steps:
- monitoring voltage at a node between at least one pair of series-connected windings, during operation of the motor at a given speed, to detect transition voltage regions that occur following energization of said pair of windings by the driving current;
- measuring the duration of said detected transition voltage regions;
- establishing at least one target duration value for said detected transition voltage regions;
- comparing said measured duration of at least one of said transition voltage regions to said target duration value;
- and
- adjusting the driving current amplitude as necessary to substantially conform said measured duration to said target duration value.
Apparatus for controlling operation of a stepping motor having a multiplicity of series-connected windings arranged in ring configuration and driven by a square waveform voltage, comprising:
- means for monitoring voltage at a node between at least one pair of series-connected windings of the motor, to detect transition voltage regions;
- means for measuring the duration of said detected transition voltage regions;
- means for comparing said measured duration of said transition voltage regions to a target duration value thereof;
- and
- means for effectively adjusting the amplitude of the current for driving the motor, as necessary to substantially conform said measured duration to said target duration value.
A motor system, comprising:
- a stepping motor having a stator comprised of a multiplicity of windings, series connected in ring configuration;
- means for providing an adjustable square waveform voltage to energize said windings as series-connected pairs, in a commutation sequence for driving said motor;
- and
- control apparatus for controlling operation of said motor, said control apparatus comprising:
- means for monitoring voltage at a node between at least one pair of said series-connected windings of said motor, to detect transition voltage regions;
- means for measuring the duration of said detected transition voltage regions;
- means for comparing said measured duration of said transition voltage regions to a target duration value thereof;
- and
- means for effectively adjusting the square waveform voltage provided by said means for providing, to thereby adjust the amplitude of the current for driving said motor as necessary to substantially conform said measured duration to said target duration value.
Dependencies are inferred from the claim text.