Linear hall device based field oriented control motor drive system

• US 10,447,186 B2
• Filed: 06/07/2017
• Issued: 10/15/2019
• 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
• Primary Examiner(s): Masih, Karen
• Application Number:
  US15/615,951
• Publication Number:
  US 20170272011A1
• Time in Patent Office: 860 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:

simultaneously producing;

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

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

normalizing the first and second signals to produce first and second normalized signals;

calculating an angular position and angular velocity of the rotor based on the first normalized signal and the second normalized 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 electric 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 is positioned perpendicular to the first linear Hall device.

3. A motor drive system comprising:

a multidimensional Hall device array including at least a first linear Hall device and a second linear Hall device, the first linear Hall device having a first output, the second linear Hall device having a second output, the first linear Hall device configured to produce a first signal at the first output indicative of magnetic field strength, and the second linear Hall device configured to produce a second signal at the second output indicative of the magnetic field strength, wherein the first Hall device is configured to receive a first bias compensation current to remove an offset from the first signal, and the second Hall device is configured to receive a second bias compensation current to remove an offset from the second signal;

angle-speed calculation logic having an angle-speed output, a first input coupled to the first output, and a second input coupled to the second output, the angle-speed calculation logic configured to produce angular speed information at the angle-speed output based on the first and second signals; and

motor controller and drive logic having an input coupled to the angle-speed output, and having motor control outputs adapted to be coupled to a motor, the motor controller and drive logic configured to provide a plurality of phase signals at the motor control outputs based on the angular speed information.

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 Hall device array, 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:

a stator having a plurality of phase inputs and field windings coupled to the phase inputs, the stator configured to receive phase signals at the phase inputs, and the field windings configured to conduct current based on the phase signals;

a rotor configured to rotate with reference to the stator, the rotor having a plurality of rotor magnets configured to produce a magnetic field based on the conducted current; and

a motor drive system positioned so as to be within the magnetic field, the motor drive system including a first linear Hall device and a second linear Hall device positioned perpendicular to each other;

wherein the first linear Hall device and the second linear Hall device are provided on a single integrated circuit (IC).

7. The PMSM of claim 6, in which the first linear Hall device has a first output, the second linear Hall device has a second output, the first linear Hall device is configured to produce a first signal at the first output indicative of magnetic field strength, the second linear Hall device is configured to produce a second signal at the second output indicative of the magnetic field strength, and the motor drive system includes:

angle-speed calculation logic having an angle-speed output, a first input coupled to the first output, and a second input coupled to the second output, the angle-speed calculation logic configured to produce angular speed information at the angle-speed output based on the first and second signals; and

motor controller and drive logic having an input coupled to the angle-speed output, and having motor control outputs coupled to the phase inputs, the motor controller and drive logic configured to provide the phase signals at the motor control outputs based on the angular speed information.

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 the single integrated circuit (IC).