Linear Hall Device Based Field Oriented Control Motor Drive System

• US 20170272011A1
• Filed: 06/07/2017
• Published: 09/21/2017
• Est. Priority Date: 12/04/2015
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Fedigan, Stephen John, Jain, Anuj, Magee, David Patrick
• Granted Patent: US 10,447,186 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 33/072 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: G01R 33/077 Vertical Hall-effect devices
• CPC Class Codes: H02K 29/08 using magnetic effect devices, e.g. Hall-plates, magneto-resistors H02K29/12 takes precedence
• CPC Class Codes: H02P 21/06 Rotor flux based control involving the use of rotor position or rotor speed sensors
• CPC Class Codes: H02P 25/03 with brushless excitation
• CPC Class Codes: H02P 6/16 Circuit arrangements for detecting position

Abstract

A motor control system for a permanent magnet synchronous motor (PMSM) uses two linear Hall devices to produce a first signal indicative of a strength of a first magnetic field component produced by a set of rotor magnets and to simultaneously produce a second signal indicative of a strength of second magnetic field component produced by the rotor magnets that is approximately orthogonal to the first magnetic field component. An angular position and angular velocity of the rotor is calculated based on the first signal and the second signal. A plurality of phase signals is produced based on the calculated angular position and angular velocity. Current in a plurality of field windings of the motor is controlled using the plurality of phase signals.

Claims

1. A method for controlling an electric motor, the method comprising:

producing a first signal indicative of a strength of a first magnetic field component produced by a set of rotor magnets included within a rotor of the electric motor using a first linear Hall device;

simultaneously producing a second signal indicative of a strength of second magnetic field component produced by the rotor magnets that is approximately orthogonal to the first magnetic field component using a second linear Hall device;

calculating an angular position and angular velocity of the rotor based on the first signal and the second signal;

producing a plurality of phase signals based on the calculated angular position and angular velocity; and

controlling current in a plurality of field windings of the motor using the plurality of phase signals.

2. The method of claim 1, in which the first linear Hall device is located adjacent the rotor, and in which the second linear Hall device positioned perpendicular to the first linear Hall device.

3. A motor drive system comprising:

a multidimensional array of at least a first linear Hall device and a second linear Hall device;

angle-speed calculation logic coupled to receive signals indicative of magnetic field strength from each of the linear Hall devices; and

motor controller and drive logic coupled to receive angular speed information from the angle-speed calculation logic, with a plurality of outputs for providing a plurality of phase signals to control a motor.

4. The system of claim 3, in which the second linear Hall device is positioned perpendicular to the first linear Hall device.

5. The system of claim 3 in which the multidimensional array of Hall devices, the angle-speed calculation logic and the motor controller and drive logic are all formed on a single integrated circuit, (IC).

6. A permanent magnet synchronous motor (PMSM) comprising:

stator having a plurality of field windings, in which the plurality of phase signals are coupled to the field windings;

rotor configured to rotate with reference to the stator, the rotor having a plurality of rotor magnets;

a motor drive system positioned so as to be within a magnetic field produced by the rotor magnets, in which the motor drive system includes a first linear Hall device and a second linear Hall device positioned perpendicular to each other.

7. The PMSM of claim 6, in which the motor drive system further includes:

angle-speed calculation logic coupled to receive signals indicative of magnetic field strength from each of the linear Hall devices; and

motor controller and drive logic coupled to receive angular speed information from the angle-speed calculation logic, with a plurality of outputs for providing a plurality of phase coupled to the field windings of the stator.

8. The PMSM of claim 7, in which the first linear Hall device, the second linear Hall device, the angle-speed calculation logic and the motor controller and drive logic are all formed on a single integrated circuit (IC).