Hall sensor alignment for BLDC motor
First Claim
Patent Images
1. A control system for a multiphase DC motor, comprising:
- a multiphase motor drive circuit;
a circuit for outputting back-EMF signals from said motor drive circuit;
Hall effect sensors and a circuit for outputting Hall signals from said sensors that are indicative of rotor position; and
a calculating circuit for calculating a phase difference between a Hall signal and a back-EMF signal.
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Abstract
A technique for determining an alignment error of a Hall sensor location in a brushless DC motor drive, by measuring the back EMF waveform, preferably while the motor is coasting. According to the technique, an angular offset is calculated between a selected BEMF waveform and a selected Hall signal. Such offsets are preferably calculated for each phase individually. The offsets may be advantageously stored in the motor control unit and used to adjust the output motor control signals for maximum torque.
42 Citations
24 Claims
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1. A control system for a multiphase DC motor, comprising:
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a multiphase motor drive circuit;
a circuit for outputting back-EMF signals from said motor drive circuit;
Hall effect sensors and a circuit for outputting Hall signals from said sensors that are indicative of rotor position; and
a calculating circuit for calculating a phase difference between a Hall signal and a back-EMF signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 21, 22)
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11. A control method for a multiphase DC motor, said motor having a multiphase motor drive circuit, a circuit for outputting back-EMF signals from said motor drive circuit, Hall effect sensors and a circuit for outputting Hall signals from said sensors that are indicative of rotor position;
- said method comprising the step of calculating a phase difference between a Hall signal and a back-EMF signal.
- View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 23, 24)
Specification