Controller for Driving a Stepper Motor

• US 20150326158A1
• Filed: 05/06/2015
• Published: 11/12/2015
• Est. Priority Date: 05/06/2014
• Status: Active Grant

• Current Assignee: Johnson Electric International AG (Johnson Electric Holdings Limited)
• Original Assignee: Johnson Electric SA 125 Rue de Progres La Chaux de Fonds Switzerland (Johnson Electric Holdings Limited)
• Inventors: Furlan, Miha, Bourqui, Yvan, Bruelhart, Maxime
• Granted Patent: US 9,825,567 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02P 6/17 and for generating speed information
• CPC Class Codes: H02P 8/04 Arrangements for starting
• CPC Class Codes: H02P 8/12 Control or stabilisation of current
• CPC Class Codes: H02P 8/14 Arrangements for controlling speed or speed and torque H02P8/12, H02P8/22 take precedence
• CPC Class Codes: H02P 8/34 Monitoring operation H02P8/36 takes precedence

Abstract

A controller is provided for driving a stepper motor with a magnetic rotor and at least one coil. The controller has a power stage for supplying the at least one coil with current, at least one analog Hall sensor for providing a signal as a function of the position of the magnetic rotor with respect to the Hall sensor, and a feedback line connecting the Hall sensor with the power stage to feed the signal of the Hall sensor back to the power stage.

Claims

1. A controller for driving a stepper motor with a magnetic rotor and at least one coil, the controller comprising:

a power stage for supplying the at least one coil with current,

at least one analog Hall sensor for providing a signal as a function of the position of the magnetic rotor with respect to the Hall sensor, and

a feedback line connecting the Hall sensor with the power stage to feed the signal of the Hall sensor back to the power stage, which is configured to supply a current to the at least one coil as a function of the signal of the Hall sensor.

2. The controller of claim 1, comprising a closed loop with a speed control stage having an input connected to the Hall sensor and an output connected to the power stage, the control stage being configured to receive the signal of the Hall sensor and to produce a reference signal to be received by the power stage, the reference signal adjusting the amplitude of the signal of the Hall sensor provided via the feedback line.

3. The controller of claim 1, wherein the speed control stage comprises another input for receiving an external signal defining a desired value for the rotational speed of the rotor.

4. The controller of claim 2, wherein the input of the speed control stage is connected via a frequency-to-voltage converter with the Hall sensor.

5. The controller of claim 1, wherein the at least one sensor is an analog Hall sensor which provides a substantially sinusoidal signal when the rotor is rotating and/or wherein the power stage is configured to produce a current to be supplied to the at least one coil which has a substantially sinusoidal wave form.

6. The controller of claim 1, comprising at least two Hall sensors for providing two signals as a function of the position of the magnetic rotor with respect to the Hall sensors, the two signals being phase-shifted.

7. The controller of claim 6, wherein the phase shift is 90°

.

8. The controller of claim 6, wherein the two Hall sensors are arranged around the rotation axis of the rotor such that the angle between them is less than 60 degrees.

9. The controller of claim 6, wherein the Hall sensors are arranged on a plate, on which the power stage is arranged.

10. The controller of claim 6, wherein the distance between the two Hall sensors is less than 3 mm.

11. The controller of claim 1, which is designed as an ASIC.

12. A stepper motor comprising the controller of claim 1.

13. The stepper motor of claim 12, comprising a rotor having a magnetic ring which extends laterally out of the stator.

14. The stepper motor of claim 12, wherein the controller is arranged on a plate, in particular a printed circuit board.

15. The stepper motor of claim 14, wherein the plate is firmly attached to a lateral extension of a coil body carrying the at least one coil.

16. The stepper motor of claim 14, wherein the at least two analog Hall sensors are arranged on the plate.

17. The stepper motor of claim 12, comprising a rotor, which is surrounded by at least two coils, which are arranged axially offset along the rotation axis of the rotor.

18. The stepper motor of claim 17, wherein the rotor has a magnet with at least 4 magnetic poles.

19. Actuator comprising the stepper motor of claim 12 and a gear drive.