DUAL LANE CONTROL OF A PERMANENT MAGNET BRUSHLESS MOTOR USING NON-TRAPEZOIDAL COMMUTATION CONTROL

• US 20090128072A1
• Filed: 11/16/2007
• Published: 05/21/2009
• Est. Priority Date: 11/16/2007
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Strong, Ronald E., Wilkens, Dean R.
• Granted Patent: US 8,084,972 B2
• Time in Patent Office: Days
• US Class Current: 318/400.170
• CPC Class Codes: H02P 2209/07 Trapezoidal waveform
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: H02P 6/14 Electronic commutators

Abstract

A motor control system and method implements non-trapezoidal motor control and meets established “fail passive” regulatory guidelines. In particular, a system and method of controlling a multi-phase brushless motor that includes a multi-pole permanent magnet rotor, and an individual, electrically isolated stator winding associated with each phase that includes a first terminal and a second terminal. A motor command is supplied to a motor control. The motor control is configured such that the first terminal of each stator winding is selectively coupled to a power source at a first duty cycle, and the second terminal of each stator winding is selectively coupled to a power source asynchronously with the first terminal of each stator winding at a second duty cycle.

Claims

1. A motor control system, comprising:

a multi-phase brushless motor including a multi-pole permanent magnet rotor and an individual, electrically isolated stator winding associated with each phase, each stator winding including a first terminal and a second terminal; and

a motor control coupled to each of the stator windings, the motor control comprising;

a first control lane responsive to a motor command signal to selectively couple the first terminal of each stator winding to a power source at a first duty cycle, the first duty cycle equal to a value of DC, and

a second control lane configured to operate asynchronously with the first control lane, the second control lane responsive to the motor command signal to selectively couple the second terminal of each stator winding to a power source at a second duty cycle, the second duty cycle equal to a value of (100%-DC).

2. The system of claim 1, wherein:

the first control lane is operable to selectively couple the first terminal of each stator winding to the power source in accordance with a first pulse width modulation (PWM) control scheme; and

the second control lane is operable to asynchronously couple the second terminal of each stator winding to the power source in accordance with a second PWM control scheme, the second control scheme being an inversion of the first PWM scheme.

3. The system of claim 2, wherein the first and second PWM control schemes are each field oriented control schemes.

4. The system of claim 3, further comprising:

a plurality of first control lane current sensors, each first control lane current sensor coupled to sense current flow through one of the stator windings and operable to supply a signal representative of the sensed current to the first control lane; and

a plurality of second control lane current sensors, each second control lane current sensor coupled to sense current flow through one of the stator windings and operable to supply a signal representative of the sensed current to the second control lane.

5. The system of claim 4, further comprising:

a first control lane position sensor coupled to sense rotor position and operable to supply a signal representative of the sensed rotor position to the first control lane; and

a second control lane position sensor coupled to sense rotor position and operable to supply a signal representative of the sensed rotor position to the second control lane.

6. The system of claim 3, wherein the first and second PWM control schemes are each sinusoidal control schemes.

7. The system of claim 6, further comprising:

a plurality of first control lane current sensors, each first control lane current sensor coupled to sense current flow through one of the stator windings and operable to supply a signal representative of the sensed current to the first control lane; and

a plurality of second control lane current sensors, each second control lane current sensor coupled to sense current flow through one of the stator windings and operable to supply a signal representative of the sensed current to the second control lane.

8. The system of claim 7, further comprising:

a first control lane position sensor coupled to sense rotor position and operable to supply a signal representative of the sensed rotor position to the first control lane; and

a second control lane position sensor coupled to sense rotor position and operable to supply a signal representative of the sensed rotor position to the second control lane.

9. The system of claim 8, further comprising:

a plurality of current sensors, each current sensor coupled to sense current flow through one of the stator windings and operable to supply a signal representative of the sensed current to the first and second control lanes; and

a position sensor coupled to sense motor rotational position and operable to supply a signal representative of the sensed rotational position to the first and second control lanes.

10. The system of claim 1, wherein:

the first control lane comprises a first pair of series-coupled switches associated with each stator winding, the first terminal of each stator winding coupled between one of the first pair of series coupled switches; and

the second control lane comprises a second pair of series-coupled switches associated with each stator winding, the second terminal of each stator winding coupled between one of the second pair of series coupled switches.

11. The system of claim 10, wherein the motor control is configured such that if a single component in either the first or the second control lanes becomes inoperable, the motor control will prevent inducement of a current that could result in an undesirable motor acceleration or rotation.

12. A motor control, comprising:

a first control lane including a plurality of first output terminals, the first control lane responsive to a motor command signal to selectively couple each of the plurality of first output terminals to a power source at a first duty cycle, the first duty cycle equal to a value of DC; and

a second control lane including a plurality of second output terminals and configured to operate asynchronously with the first control lane, the second control lane responsive to the motor command signal to couple each of the plurality of second output terminals to the power source at a second duty cycle, the second duty cycle equal to a value of (100%-DC).

13. The motor control of claim 12, wherein:

the first control lane is operable to selectively couple each of the plurality of first output terminals to the power source in accordance with a first pulse width modulation (PWM) control scheme; and

the second control lane is operable to asynchronously couple each of the second output terminals to the power source in accordance with a second PWM control scheme, the second control scheme being an inversion of the first PWM scheme.

14. A method of controlling a multi-phase brushless motor that comprises a multi-pole permanent magnet rotor and an individual, electrically isolated stator winding associated with each phase, wherein each stator winding includes a first terminal and a second terminal, the method comprising the steps of:

supplying a motor command;

selectively coupling the first terminal of each stator winding to a power source at a first duty cycle having a value of DC;

selectively coupling the second terminal of each stator winding to a power source asynchronously with the first terminal of each stator winding at a second duty cycle having a value of (100%-DC).

15. A motor control system, comprising:

a brushless motor including a multi-phase stator and a multi-pole permanent magnet rotor, the multi-phase stator operable, upon being energized, to generate and apply a torque to the rotor; and

a motor control coupled to, and operable to selectively energize, the multi-phase stator, the motor control comprising;

a first control lane coupled to receive the motor command signal and operable, in response to the motor command, to generate a plurality of first pulse width modulated (PWM) voltage signals,

a second control lane coupled to receive the motor command signal and operable, in response to the motor command, to generate a plurality of second pulse width modulated (PWM) voltage signals,

a vector sum output circuit coupled to receive the plurality of first PWM voltage signals and the plurality of second PWM voltage signals, the vector sum output circuit operable to generate (i) a plurality of vector sum voltage signals from the plurality of first and second PWM voltage signals and (ii) a plurality of average PWM voltage signals from the plurality of vector sum voltage signals, and

a plurality of controllable switches, each controllable switch coupled to receive one of the average PWM voltage signals and operable, in response thereto, to selectively open and close, to thereby selectively energize and de-energize the multi-phase stator.

16. The system of claim 15, wherein the vector sum output circuit comprises:

a first PWM average circuit coupled to receive the first PWM voltage signals and the second PWM voltage signals, the first PWM average circuit operable to generate a plurality of first PWM average voltage signals and a plurality of first inverted PWM average voltage signals, each first PWM average voltage signal at least substantially equal to the mathematical average of one of the first PWM voltage signals and one of the second PWM voltage signals, each first inverted PWM average voltage signal at least substantially equal to an inversion of one of the first PWM average voltage signals;

a second PWM average circuit coupled to receive the first PWM voltage signals and the second PWM voltage signals, the second PWM average circuit operable to generate a plurality of second PWM average voltage signals and a plurality of inverted second PWM average voltage signals, each second PWM average voltage signal at least substantially equal to the mathematical average of one of the first PWM voltage signals and one of the second PWM voltage signals, each inverted second PWM average voltage signal at least substantially equal to an inversion of one of the second PWM average voltage signals;

a first plurality of AND gates each coupled to receive one of the first PWM average voltage signals and one of the second PWM average voltage signals; and

a second plurality of AND gates each coupled to receive one of the inverted first PWM average voltage signals and one of the inverted second PWM average voltage signals.

17. The system of claim 16, wherein the first and second PWM average circuits each comprise:

a plurality of accumulator pairs, each accumulator pair coupled to receive and accumulate one of the first PWM voltage signals and one of the second PWM voltage signals;

a plurality of averaging circuits, each averaging coupled to receive the accumulated first PWM signals and the accumulated second PWM signals from one of the accumulator pairs, each averaging circuit operable to supply an average signal representative of the mathematical average of the accumulated first PWM signals and the accumulated second PWM signals;

a plurality of PWM generators, each PWM generator coupled to receive the average signal from one of the averaging circuits and operable to supply one of the first or second PWM average voltage signals; and

a plurality of inverters, each inverter coupled between a PWM generator and an AND gate.

18. The system of claim 17, wherein:

the first PWM average circuit further comprises a first triangle generator operable to generate a first triangle wave;

the second PWM average circuit further comprises a second triangle generator operable to generate a second triangle wave, the second triangle generator in operable communication with the first triangle generator and generating the second triangle wave at least substantially synchronously with the first triangle wave;

each PWM generator that comprises the first PWM average circuit comprises a comparator coupled to receive the first triangle wave and the average signal from one of the averaging circuits and operable to supply the first PWM average voltage signals; and

each PWM generator that comprises the second PWM average circuit comprises a comparator coupled to receive the second triangle wave and the average signal from one of the averaging circuits and operable to supply the second PWM average voltage signals.

19. A motor control for selectively energizing a multi-phase stator, comprising:

a first control lane coupled to receive a motor command signal and operable, in response to the motor command, to generate a plurality of first pulse width modulated (PWM) voltage signals,

a second control lane coupled to receive the motor command signal and operable, in response to the motor command, to generate a plurality of second pulse width modulated (PWM) voltage signals,

a vector sum output circuit coupled to receive the plurality of first PWM voltage signals and the plurality of second PWM voltage signals, the vector sum output circuit operable to generate (i) a plurality of vector sum voltage signals from the plurality of first and second PWM voltage signals and (ii) a plurality of average PWM voltage signals from the plurality of vector sum voltage signals, and

a plurality of controllable switches, each controllable switch coupled to receive one of the average PWM voltage signals and operable, in response thereto, to selectively open and close.

20. The motor control of claim 19, wherein the vector sum output circuit comprises:

a first PWM average circuit coupled to receive the first PWM voltage signals and the second PWM voltage signals, the first PWM average circuit operable to generate a plurality of first PWM average voltage signals and a plurality of first inverted PWM average voltage signals, each first PWM average voltage signal at least substantially equal to the mathematical average of one of the first PWM voltage signals and one of the second PWM voltage signals, each first inverted PWM average voltage signal at least substantially equal to an inversion of one of the first PWM average voltage signals;

a second PWM average circuit coupled to receive the first PWM voltage signals and the second PWM voltage signals, the second PWM average circuit operable to generate a plurality of second PWM average voltage signals and a plurality of inverted second PWM average voltage signals, each second PWM average voltage signal at least substantially equal to the mathematical average of one of the first PWM voltage signals and one of the second PWM voltage signals, each inverted second PWM average voltage signal at least substantially equal to an inversion of one of the second PWM average voltage signals;

a first plurality of AND gates each coupled to receive one of the first PWM average voltage signals and one of the second PWM average voltage signals; and

a second plurality of AND gates each coupled to receive one of the inverted first PWM average voltage signals and one of the inverted second PWM average voltage signals.