US5512805A — Method and apparatus for determining reverse rota…

Claim 1

Independent Claim 140 words

A circuit for operating a polyphase de motor having a plurality of driving coils for causing a rotor to turn when drive signals are applied to said driving coils, comprising: circuitry commutatively applying drive signals to said plurality of driving coils for causing the rotor to turn; circuitry for producing a warning signal if the rotor turns in an undesired direction; circuitry for receiving the back emf of a selected one of said driving coils at a time when said driving coil is in a floating state; circuitry for determining an anticipated direction said back emf will cross a reference voltage; and circuitry for determining if the back emf received by said circuitry for receiving the back emf crosses a reference voltage from other than said anticipated direction to produce a signal to said circuitry for producing a warning signal.

Claim 2

Dependent Claim 140 words

A circuit for operating a polyphase de motor having a plurality of driving coils for causing a rotor to turn when drive signals are applied to said driving coils, comprising: circuitry commutatively applying drive signals to said plurality of driving coils for causing the rotor to turn; circuitry for producing a warning signal if the rotor turns in an undesired direction; circuitry for receiving the back emf of a selected one of said driving coils at a time when said driving coil is in a floating state; circuitry for determining an anticipated direction said back emf will cross a reference voltage; and circuitry for determining if the back emf received by said circuitry for receiving the back emf crosses a reference voltage from other than said anticipated direction to produce a signal to said circuitry for producing a warning signal.

Claim 3

Dependent Claim 144 words

A circuit for generating a reverse rotation signal in the operation of a polyphase dc motor having a plurality of driving coils, comprising: a comparator having a first input coupled to receive the back emf of one of said driving coils when in a floating state, having a second input coupled to a reference voltage, and having an output; circuitry for determining an anticipated direction in which said back emf will cross the reference voltage based upon a commutation sequence of the polyphase dc motor, and for producing a slope signal indicating the anticipated direction; and circuitry, having an input coupled to the output of the comparator and having an input coupled to receive the slope signal, for generating the reverse rotation signal responsive to a transition at the output of the comparator not corresponding to the anticipated direction indicated by the slope signal.

Claim 4

Dependent Claim 144 words

A circuit for generating a reverse rotation signal in the operation of a polyphase dc motor having a plurality of driving coils, comprising: a comparator having a first input coupled to receive the back emf of one of said driving coils when in a floating state, having a second input coupled to a reference voltage, and having an output; circuitry for determining an anticipated direction in which said back emf will cross the reference voltage based upon a commutation sequence of the polyphase dc motor, and for producing a slope signal indicating the anticipated direction; and circuitry, having an input coupled to the output of the comparator and having an input coupled to receive the slope signal, for generating the reverse rotation signal responsive to a transition at the output of the comparator not corresponding to the anticipated direction indicated by the slope signal.

Claim 5

Dependent Claim 26 words

The circuit of claim 2 wherein said comparator circuit receives the back emf at a time prior to commutation of the one of said driving coils.

Claim 6

Dependent Claim 25 words

The circuit of claim 3 wherein said circuitry for determining an anticipated direction detects whether said reference voltage crossing occurs with negative or positive slope.

Claim 7

Dependent Claim 18 words

The circuit of claim 3 wherein said polyphase dc motor is a brushless sensorless 3 phase dc motor.

Claim 8

Dependent Claim 52 words

The circuit of claim 3 further comprising circuitry for providing a reference crossing signal responsive to the back emf crossing the reference voltage; and wherein said circuitry for generating the reverse rotation signal comprises: a pair of logic gates having inputs receiving the anticipated slope direction and reference voltage crossing indicating signals.

Claim 9

Dependent Claim 33 words

The circuit of claim 3 further comprising circuitry for selecting among various ones of said driving coils as said driving signals are switched to a floating state in accordance with the commutative sequence.

Claim 10

Dependent Claim 216 words

A circuit for operating a polyphase dc motor having a plurality of driving coils, comprising: a driver for applying drive signals to said driving coils; an incrementable sequencer for controlling said driver to apply said drive signals in a commutative sequence to said driving coils in which at least one of said coils is selected to float without drive signals during a portion of said commutative sequence; a back emf amplifier for amplifying the back emf on said selected at least one floating coil; circuitry for determining an anticipated direction the back emf on said selected at least one floating coil will cross a reference voltage; a reference voltage crossing detector for determining when the back emf on said selected at least one floating coil crosses the reference voltage from the anticipated direction; a synchronizing circuit to determine which of said plurality of coils should be said at least one floating coil and to connect said determined coil to said back emf amplifier; circuitry responsive to said reference voltage crossing detector to increment said sequencer in said commutative sequence; and circuitry responsive to said reference voltage crossing detector for producing a signal when said back emf of said selected at least one floating coil crosses the reference voltage in a direction other than the anticipated direction.

Claim 11

Dependent Claim 216 words

A circuit for operating a polyphase dc motor having a plurality of driving coils, comprising: a driver for applying drive signals to said driving coils; an incrementable sequencer for controlling said driver to apply said drive signals in a commutative sequence to said driving coils in which at least one of said coils is selected to float without drive signals during a portion of said commutative sequence; a back emf amplifier for amplifying the back emf on said selected at least one floating coil; circuitry for determining an anticipated direction the back emf on said selected at least one floating coil will cross a reference voltage; a reference voltage crossing detector for determining when the back emf on said selected at least one floating coil crosses the reference voltage from the anticipated direction; a synchronizing circuit to determine which of said plurality of coils should be said at least one floating coil and to connect said determined coil to said back emf amplifier; circuitry responsive to said reference voltage crossing detector to increment said sequencer in said commutative sequence; and circuitry responsive to said reference voltage crossing detector for producing a signal when said back emf of said selected at least one floating coil crosses the reference voltage in a direction other than the anticipated direction.

Claim 12

Dependent Claim 44 words

The circuit of claim 8 wherein said circuitry for determining an anticipated direction the back emf on said selected at least one floating coil will cross a reference voltage comprises circuitry to detect whether said reference voltage crossing occurs with negative or positive slope.

Claim 13

Dependent Claim 26 words

The circuit of claim 8 wherein said circuit for operating a polyphase dc motor is a circuit for operating a brushless sensorless 3 phase dc motor.

Claim 14

Dependent Claim 51 words

The circuit of claim 8 wherein said circuitry for determining if the back emf received by said circuitry for receiving the back emf crosses a reference voltage from other than said anticipated direction comprises a pair of NAND gates having inputs receiving inverted anticipated slope direction and zero crossing indicating signals.

Claim 15

Independent Claim 188 words

A method for operating a polyphase dc motor having a plurality of driving coils and having a rotor, comprising the steps of: determining the actual instantaneous position of the rotor of the motor by comparing the back emf of a coil to a reference voltage at a time when the coil is in a floating state and by detecting the direction in which the back emf of the coil crosses the reference voltage; generating a reference voltage crossing direction signal indicating the direction in which the back emf crosses the reference voltage; determining a desired rotor position precedent to executing a desired commutation sequence by generating an anticipated slope direction signal indicating the direction in which the back emf is anticipated to cross the reference voltage in the desired commutation sequence; executing said desired commutation sequence responsive to the actual instantaneous position of the rotor corresponding to the desired rotor position; comparing the signal indicating the anticipated slope direction signal to the reference voltage crossing direction signal; and generating a reverse rotation signal responsive to the anticipated slope direction signal not matching the reference voltage crossing direction signal.

Claim 16

Independent Claim 188 words

A method for operating a polyphase dc motor having a plurality of driving coils and having a rotor, comprising the steps of: determining the actual instantaneous position of the rotor of the motor by comparing the back emf of a coil to a reference voltage at a time when the coil is in a floating state and by detecting the direction in which the back emf of the coil crosses the reference voltage; generating a reference voltage crossing direction signal indicating the direction in which the back emf crosses the reference voltage; determining a desired rotor position precedent to executing a desired commutation sequence by generating an anticipated slope direction signal indicating the direction in which the back emf is anticipated to cross the reference voltage in the desired commutation sequence; executing said desired commutation sequence responsive to the actual instantaneous position of the rotor corresponding to the desired rotor position; comparing the signal indicating the anticipated slope direction signal to the reference voltage crossing direction signal; and generating a reverse rotation signal responsive to the anticipated slope direction signal not matching the reference voltage crossing direction signal.

Claim 17

Independent Claim 143 words

A method for operating a polyphase dc motor having a plurality of driving coils, comprising: applying drive signals to said driving coils in a commutative sequence in which at least one of said coils is selected to float without drive signals during a portion of said commutative sequence; amplifying a back emf signal on said selected at least one floating coil; determining an anticipated direction that the back emf on said selected at least one floating coil will cross a reference voltage to provide an anticipated slope direction indicating signal; determining when the back emf on said selected at least one floating coil crosses the reference voltage to provide a reference voltage crossing indicating signal; and producing a signal when said back emf of said selected at least one floating coil crosses the reference voltage in a direction other than the anticipated direction.

Claim 18

Independent Claim 143 words

A method for operating a polyphase dc motor having a plurality of driving coils, comprising: applying drive signals to said driving coils in a commutative sequence in which at least one of said coils is selected to float without drive signals during a portion of said commutative sequence; amplifying a back emf signal on said selected at least one floating coil; determining an anticipated direction that the back emf on said selected at least one floating coil will cross a reference voltage to provide an anticipated slope direction indicating signal; determining when the back emf on said selected at least one floating coil crosses the reference voltage to provide a reference voltage crossing indicating signal; and producing a signal when said back emf of said selected at least one floating coil crosses the reference voltage in a direction other than the anticipated direction.

Claim 19

Dependent Claim 39 words

The method of claim 13 wherein said step of determining when the back emf on said selected at least one floating coil crosses the reference voltage comprises determining whether said reference voltage crossing occurs with negative or positive slope.

Claim 20

Dependent Claim 45 words

The method of claim 13 wherein said step of determining if the back emf received by said circuitry for receiving the back emf crosses a reference voltage from other than said anticipated direction comprises comparing the anticipated slope direction and reference voltage crossing indicating signals.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-04-30	1999-10-30	2000-04-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-04-30	2003-10-30	2004-04-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-04-30	2007-10-30	2008-04-30	$7700.00	Window Closed / Lapsed

Method and apparatus for determining reverse rotation of a polyphase DC motor

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