Method for detecting the position of a rotor of a DC motor and related circuit
First Claim
1. Method for detecting the position of a rotor of a DC motor with N phases having a plurality of windings, comprising:
- connecting two of said windings between first and second prefixed voltages through to a first current path for a prefixed time;
allowing the current stored in said two windings to discharge through a second current path;
comparing a voltage across one of said two windings with a reference voltage and providing a control signal when said voltage is smaller in absolute value than said reference voltage;
performing the above steps for each of plural winding pairs of the windings of said motor; and
detecting the position of said rotor on the base of the control signals obtained.
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Accused Products
Abstract
A method for detecting the position of a rotor of a DC motor with N phases having a plurality of windings, comprising the steps of connecting two of the windings between first and second prefixed voltages through to a first current path for a prefixed time, allowing the current stored in the two windings to discharge through a second current path; comparing the voltage across one of the two windings with a reference voltage and providing a control signal when the voltage is smaller in absolute value than the reference voltage, performing the above steps for each of the winding pairs of the motor; detecting the position of the rotor on the basis of the control signals obtained.
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Citations
19 Claims
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1. Method for detecting the position of a rotor of a DC motor with N phases having a plurality of windings, comprising:
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connecting two of said windings between first and second prefixed voltages through to a first current path for a prefixed time;
allowing the current stored in said two windings to discharge through a second current path;
comparing a voltage across one of said two windings with a reference voltage and providing a control signal when said voltage is smaller in absolute value than said reference voltage;
performing the above steps for each of plural winding pairs of the windings of said motor; and
detecting the position of said rotor on the base of the control signals obtained. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Circuit for detecting the current of a DC motor with three phases, comprising:
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three half-bridges for driving said motor;
a voltage comparator having a first input applied to a supply voltage and having a second input connected to a controlled selector, said controlled selector allowing the selective connection of said second input of the comparator to a central point of any one of said three half-bridges, in response to a control signal; and
a control logic that receives in input the output of said comparator, detecting the position of the rotor therefrom.
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13. A method, comprising:
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introducing a voltage across a pair of series connected motor windings for a period, Tact;
measuring, after the introducing step, a voltage over time across one motor winding of the pair of motor windings; and
determining, based on a result of the measuring step, the position of a motor rotor with respect to the pair of windings. - View Dependent Claims (14, 15)
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16. A device, comprising:
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a pair of motor windings;
means for selectively coupling a first end of the series connected windings to a supply voltage and a second end of the windings to a circuit ground for a selected period, T1; and
means for comparing a voltage across one of the pair of windings with the supply voltage, after the period T1. - View Dependent Claims (17, 18, 19)
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Specification