Permanent magnet synchronous motor and controller therefor
First Claim
1. A permanent magnet synchronous motor having a stator and a rotor, the stator having windings and the rotor comprising a plurality of permanent magnets, and a controller, the controller comprising:
- two magnetic field sensors, each having a linear response to sensed magnetic field strength, the sensors being spaced by an angle A electrical degrees relative to the rotor, where angle A is greater than 0 degrees and less than 180 degrees or greater than 180 degrees and less than 360 degrees, for sensing the position of the rotor by sensing a magnetic field representative of the fields of the magnets of the rotor;
normalizing means for producing first and second signals representing normalized orthogonal components of the outputs of the sensors; and
energizing means for producing, from the said orthogonal components, sinusoidal currents for energizing the windings of the stator to drive the rotor, the energizing means including a transformer that transforms the normalized first and second signals into 3-phase synchronous sinusoidal waveforms;
wherein the normalizing means produces the first and second signals with a uniform amplitude.
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Accused Products
Abstract
A low-cost sine-wave drive for a 3-phase permanent magnet synchronous AC machines (PMSM) in open-loop control is based on the measurements of two linear Hall sensors. The two Hall sensors are excited by a magnetic ring with the same pole number as the PMSM rotor magnet and sinusoidal flux distributions. The output signals of the Hall sensors are unified through a two-phase-type phase-lock-loop in order to reduce the impact of the sensor mounting non-uniformity during mass production. The peak torque and speed of motor is simply controlled by adjusting the amplitude of pulse-width-modulation carrier. Smooth torque control is achieved due to sinusoidal 3-phase currents. Such a simple sine-wave drive can be achieved with or without the assistance of a micro-controller unit (MCU). No current sensor is required for the motor phase current detection. This motor can be used in industrial applications where there is no strict requirement on torque response and constant speed control of PMSM machines.
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Citations
17 Claims
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1. A permanent magnet synchronous motor having a stator and a rotor, the stator having windings and the rotor comprising a plurality of permanent magnets, and a controller, the controller comprising:
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two magnetic field sensors, each having a linear response to sensed magnetic field strength, the sensors being spaced by an angle A electrical degrees relative to the rotor, where angle A is greater than 0 degrees and less than 180 degrees or greater than 180 degrees and less than 360 degrees, for sensing the position of the rotor by sensing a magnetic field representative of the fields of the magnets of the rotor; normalizing means for producing first and second signals representing normalized orthogonal components of the outputs of the sensors; and energizing means for producing, from the said orthogonal components, sinusoidal currents for energizing the windings of the stator to drive the rotor, the energizing means including a transformer that transforms the normalized first and second signals into 3-phase synchronous sinusoidal waveforms; wherein the normalizing means produces the first and second signals with a uniform amplitude. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A controller for use with a permanent magnet synchronous motor having a stator and a rotor, the stator having windings and the rotor comprising a plurality of permanent magnets;
- the controller comprising;
inputs for connection to two magnetic field sensors, each having a linear response to sensed magnetic field strength, the sensors being spaced by an angle A electrical degrees relative to the rotor, where angle A is greater than 0 degrees and less than 180 degrees or greater than 180 degrees and less than 360 degrees, for sensing the position of the rotor by sensing a magnetic field representative of the fields of the magnets of the rotor; means for producing first and second signals representing normalized orthogonal components of the outputs of the sensors; and means for producing, from the said orthogonal components, pulse width modulated currents for application to an inverter for energizing the windings of the stator to drive the rotor the means for producing pulse width modulated currents including a transformer that transforms the normalized first and second signals into 3-phase synchronous sinusoidal waveforms; wherein the normalizing means produces the first and second signals with a uniform amplitude. - View Dependent Claims (16, 17)
- the controller comprising;
Specification