Control system, method of operating an electronically commutated motor, and laundering apparatus

A control system for an electronically commutated motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the control system comprising:

• commutating means for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• pulse width modulating means connected to said commutating means for pulse width modulating the DC voltage so that the DC voltage is applied by said commutating means in voltage pulses having a predetermined maximum duty cycle;
• and
• means integrating connected to said pulse width modulating means for repeatedly integrating the DC voltage over the width of each of the voltage pulses and truncating each of the voltage pulses upon the integration reaching a predetermined level, said integrating means being reset before each voltage pulse.

The control system as set forth in claim 17 further comprising:

• means for sensing a back emf signal indicative of the back emf condition of at least one winding stage;
• commutation pulse generating means responsive to the back emf signal for generating a commutation pulse when the back emf signal indicates that a predetermined angular position of the rotatable assembly has been reached;
• and
• means connected to the commutation pulse generating means for generating a set of control signals for said commutating means in response to receipt of a pulse to commutate the winding stages.

A control system for an electronically commutated motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the control system comprising:

• commutating means responsive to a set of control signals for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• commutation signal producing means responsive to a back emf signal indicative of the back emf condition of at least one winding stage for producing a commutation signal indicative of a predetermined angular position of the rotatable assembly;
• and
• control signal means responsive to the commutation signal for providing the set of control signals to said commutating means to commutate the winding stages when the rotatable assembly reaches the predetermined angular position;
• said control signal means including inhibiting means for inhibiting the operation of said commutation signal producing means for first lengths of time after corresponding occurrences of the commutation signal so that the first lengths of time are approximately a predetermined fraction of respective varying lengths of time between successive commutations, whereby commutation currents are prevented from affecting said commutation signal producing means.

A control system for an electronically commutated motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the control system comprising:

• commutating means responsive to a set of control signals for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• position sensing and providing means for sensing the angular position of the rotatable assembly and for providing a commutation signal indicative of a predetermined angular position of the rotatable assembly;
• control signal means responsive to said position sensing and providing means for generating the set of control signals for said commutating means to commutate the winding stages when the rotatable assembly reaches the predetermined angular position;
• and
• inhibiting means including means for comparing the motor current with a predetermined maximum value and actuable means connected to said comparing means for inhibiting the control signal means to prevent the generation of the set of control signals when the motor current exceeds the predetermined maximum value, said actuable means having input means for receiving a resetting signal and including means for maintaining the inhibition of said control signal means until a resetting signal appears at the input means.

A control system for an electronically commutated motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, said control system comprising:

• commutating means responsive to a set of control signals for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly, each winding stage having at least two terminals, one of which is commonly connected to one terminal of each of the other winding stages and the DC voltage is applied to pairs of other terminals of the winding stages in at least one preselected sequence;
• logic means responsive to a signal representative of the angular position of the rotatable assembly for supplying the control signals to said commutating means in a sequence in which for each commutation one of the winding stages which was energized before commutation remains energized after commutation and the other winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in the winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• and
• pulse width modulating means for pulse width modulating the control signal associated with the winding stage which was commutated on until a time after commutation and for shifting at that time to pulse width modulate the control signal associated with the winding stage which will be deenergized after the next commutation.

A control system for an electronically commutated motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, said control system comprising:

• commutating means responsive to a set of control signals for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly, each winding stage having at least two terminals, one of which is commonly connected to one terminal of each of the other winding stages and the DC voltage is applied to pairs of other terminals of the winding stages in at least one preselected sequence, said commutating means including first drive means associated with each winding stage for allowing the flow of current through its associated winding stage in a first direction in response to a first one of the control signals and second drive means associated with each winding stage for allowing the flow of current through its associated winding stage in the opposite direction in response to a second one of the control signals;
• logic means responsive to a signal representative of the angular position of the rotatable assembly for supplying the control signals to said commutating means in a sequence in which for each commutation one of the winding stages which was energized before commutation remains energized after commutation and the other winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in the winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• and
• pulse width modulating means responsive to respective successive commutations for pulse width modulating the control signals for said first drive means, then shifting to pulse width modulate the control signals for said second drive means upon the expiration of a first time period after one commutation and subsequently shifting back to pulse width modulate the control signals for said first drive means upon the expiration of a second time period after the next commutation.

A control system for an electronically commutated motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, said control system comprising:

• commutating means responsive to a set of control signals for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly, each winding stage having at least two terminals, one of which is commonly connected to one terminal of each of the other winding stages and the DC voltage is applied to pairs of other terminals of the winding stages in at least one preselected sequence;
• logic means responsive to a signal representative of the angular position of the rotatable assembly for supplying the control signals to said commutating means in a sequence in which for each commutation one of the winding stages which was energized before commutation remains energized after commutation and the other winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in the winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• pulse width modulating means for pulse width modulating the control signals;
• and
• means responsive to a commutation selection signal for controlling said pulse width modulating means when the commutation selection signal is in a first state to pulse width modulate the control signal associated with the winding stage which is commutated on until a time after commutation and for shifting at that time to pulse width modulate the control signal associated with the winding stage which will be deenergized after the next commutation and for controlling said pulse width modulating means when the commutation selection signal is in a second state to pulse width modulate upon commutation the control signal associated with the winding stage which remained on.

A control system for an electronically commutated motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, said control system comprising:

• commutating means responsive to a set of control signals for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly, each winding stage having at least two terminals, one of which is commonly connected to one terminal of each of the other winding stages and the DC voltage is applied to pairs of other terminals of the winding stages in at least one preselected sequence, said commutating means including first drive means associated with each winding stage for allowing the flow of current through its associated winding stage in a first direction in response to a first one of the control signals and second drive means associated with each winding stage for allowing the flow of current through its associated winding stage in the opposite direction in response to a second one of the control signals;
• logic means responsive to a signal representative of the angular position of the rotatable assembly for supplying the control signals to said commutating means in a sequence in which for each commutation one of the winding stages which was energized before commutation remains energized after commutation and the other winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in the winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• means for generating a drive selection signal which changes state every commutation;
• and
• means responsive to the drive selection signal for pulse width modulating the control signals for said first drive means and then shifting to pulse width modulate the control signals for said second drive means when the drive selection signal changes state upon commutation and subsequently shifting back to pulse width modulate the control signals for said first drive means when the drive selection signal again changes state upon the next commutation.

A control system for an electronically commutated, two-speed motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the control system comprising:

• commutating means responsive to a set of control signals for commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• back emf sensing means for sensing a back emf signal indicative of the back emf condition of at least one winding
• integrating means for integrating a portion of the back emf signal and for producing a commutation signal indicative of a predetermined angular position of the rotatable assembly;
• control signal means responsive to the commutation signal for providing the set of control signals to said commutating means to commutate the winding stages when the rotatable assembly reaches the predetermined angular position;
• and
• time constant providing means responsive to a speed control signal for providing two different time constants for said integrating means corresponding to the two speeds of the motor.

A laundering apparatus comprising in combination:

• a rotatable component;
• an electronically commutated motor, said motor comprising rotatable assembly means for driving the rotatable component and a stationary assembly with a plurality of winding stages;
• a control system connected to said motor;
• and
• means for applying a DC voltage to said control system;
• said control system including controlling means for controlling the application of the DC voltage to provide a resultant effective voltage to said winding stages, said controlling means including commutating means for commutating said winding stages by applying the DC voltage thereto in at least one preselected sequence to cause rotation of said rotatable assembly means, thereby to cause rotation of said rotatable component;
• approximating means for approximating a neutral conductor voltage for said motor wherein said approximating means has outputs for each of a plurality of pairs of said winding stages, the voltage on each output being a function of the sum of the terminal voltages of its associated pair of winding stages;
• and
• comparing means for comparing the approximated neutral conductor voltage with the terminal voltage of one of said winding stages, the output of said comparing means representing the angular position of said rotatable assembly means;
• said controlling means further including means responsive to the output of said comparing means to cause said commutating means to commutate said winding stages when said rotatable assembly means reaches a predetermined angular position.

A laundering apparatus comprising in combination:

• a rotatable component;
• an electronically commutated DC motor, said motor comprising rotatable assembly means for driving the rotatable component and a stationary assembly with a plurality of winding stages;
• a control system connected to said motor;
• and
• means for applying a DC voltage to said control system;
• said control system commutating including means responsive to a set of control signals for commutating said winding stages by applying the DC voltage thereto in at least one preselected sequence to cause rotation of said rotatable assembly means;
• integrating means for integrating a portion of a back emf signal indicative of the back emf condition of at least one of said winding stages to produce an output indicative of the angular position of said rotatable assembly means;
• first pulse generating means responsive to the output of said integrating means for generating a pulse when said integrating means output reaches a predetermined level;
• control signal means connected to said first pulse generating means for providing the set of control signals to said commutating means in response to receipt of a pulse to commutate said winding stages, said control signal means including inhibiting means for inhibiting the operation of said integrating means for first lengths of time after corresponding occurrences of the pulse from said first pulse generating means so that the first lengths of time are approximately a predetermined fraction of respective varying lengths of time between successive commutations, whereby commutation currents are prevented from affecting said integrating means.

A laundering apparatus comprising a combination:

• a rotatable component;
• an electronically commutated motor, said motor comprising rotatable assembly means for driving the rotatable component and a stationary assembly with a plurality of winding stages;
• a control system connected to said motor;
• and
• means for supplying a DC voltage to said control system;
• said control system including commutating means responsive to a set of control signals for commutating said winding stages by applying the DC voltage thereto in at least one preselected sequence to cause rotation of said rotatable assembly means, each winding stage having at least two terminals, one of which is commonly connected to one terminal of each of the other winding stages and the DC voltage is applied to pairs of other terminals of said winding stages in at least one preselected sequence;
• logic means responsive to a signal representative of the angular position of said rotatable assembly means for supplying the control signals to said commutating means in a sequence in which for each communtation one of said winding stages which was energized before commutation remains energized after commutation and another winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in said winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• and
• pulse width modulating means for pulse width modulating the control signal associated with said winding stage which was commutated on until a time after commutation and for shifting at that time a pulse width modulate the control signal associated with said winding stage which will be deenergized after the next commutation.

A laundering apparatus comprising in combination:

• a rotatable component;
• an electronically commutated motor, said motor comprising rotatable assembly means for driving the rotatable component and a stationary assembly with a plurality of winding stages;
• a control system connected to said motor;
• and
• means for applying a DC voltage to said control system;
• said control system including commutating means for commutating said winding stages by applying the DC voltage thereto in at least one preselected sequence to cause rotation of said rotatable assembly means;
• pulse width modulating means connected to said commutating means for pulse width modulating the DC voltage so that the DC voltage is applied by said commutating means in voltage pulses having a predetermined maximum duty cycle;
• and
• integrating means connected to said pulse width modulating means for repeatedly integrating the DC voltage over the width of each of the voltage pulses and truncating each of the voltage pulses upon the integration reaching a predetermined level, said integrating means being reset before each voltage pulse.

A laundering apparatus comprising in combination:

• a rotatable component;
• an electronically commutated motor, said motor comprising rotatable assembly means for driving the rotatable component and a stationary assembly with a plurality of winding stages;
• a control system connected to said motor;
• and
• means for supplying a DC voltage to said control system;
• said control means including commutating means responsive to a set of control signals for commutating said winding stages by applying the DC voltage thereto in at least one preselected sequence to cause rotation of said rotatable assembly means, each winding stage having at least two terminals, one of which is commonly connected to one terminal of each of the other winding stages and the DC voltage is applied to pairs of other terminals of said winding stages in at least one preselected sequence, said commutating means including first drive means associated with each winding stage for allowing the flow of current through its associated winding stage in a first direction in response to a first one of the control signals and second drive means associated with each winding stage for allowng the flow of current through its associated winding stage in the opposite direction in response to a second one of the control signals;
• logic means responsive to a signal representative of the angular position of said rotatable assembly means for supplying the control signals to said commutating means in a sequence in which for each commutation one of said winding stages which was energized before commutation remains energized after commutation and another winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in said winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• and
• pulse width modulating means responsive to respective successive commutations for pulse width modulating the control signals for said first drive means, then shifting to pulse width modulate the control signals for said second drive means upon the expiration of a first time period after one commutation and subsequently shifting back to pulse width modulate the control signals for the first drive means upon the expiration of a second time period after the next commutation.

A laundering apparatus comprising in combination:

• a rotatable component;
• an electronically commutated, two-speed motor, said motor comprising rotatable assembly means for driving the rotatable component and a stationary assembly with a plurality of winding stages;
• a control system connected to said motor;
• and
• means for applying a DC voltage to said control system;
• said control system including commutating means responsive to a set of control signals for commutating said winding stages by applying the DC voltage thereto in at least one preselected sequence to cause rotation of said rotatable assembly means;
• back emf sensing means for sensing a back emf signal indicative of the back emf condition of at least one winding stage;
• integrating means for integrating a portion of the back emf signal and for producing a commutation signal indicative of a predetermined angular position of said rotatable assembly means;
• and
• control signal means responsive to the commutation signal for providing the set of control signals to said commutating means to commutate said winding stages when said rotatable assembly means reaches the predetermined angular position;
• and
• means responsive to a speed control signal for providing two different time constants for said integrating means corresponding to the two speeds of said motor.

A method of operating an electronically commutated motor with the motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• approximating a neutral conductor voltage for the motor at outputs corresponding to each of a plurality of pairs of the winding stages, the voltage on each of the outputs being a function of the sum of the terminal voltages of its corresponding pair of winding stages;
• and
• comparing the approximated neutral conductor voltage with the terminal voltage of one of the winding stages, the result of the comparison representing the angular position of the rotatable assembly;
• the commutation of the winding stages occurring when the rotatable assembly reaches a predetermined angular position.

A method of operating an electronically commutated motor with the motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• commutating the winding stages in response to a set of control signals by applying the DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• sensing a back emf signal indicative of the back emf condition of at least one winding stage;
• producing a commutation signal indicative of a predetermined angular position of the rotatable assembly in response to the sensed back emf signal;
• providing the set of control signals in response to the commutation signal to commutate the winding stages when the rotatable assembly reaches the predetermined angular position;
• and
• inhibiting the sensing step for respective intervals of time after occurrences of the commutation signal so that the intervals of time are approximately a predetermined fraction of respective varying lengths of time between successive occurrences of the commutation signal, whereby commutation currents are prevented from being sensed.

A method of operating an electronically commutated motor with the motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• commutating the winding stages by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• pulse width modulating the DC voltage so that the DC voltage is applied in said commutating step in voltage pulses having a predetermined maximum duty cycle;
• and
• controlling said pulse width modulating by repeatedly integrating the DC voltage over the width of each of the voltage pulses, the integrating beginning from a value that is reset before each voltage pulse, and truncating each of the voltage pulses upon the integrating reaching a predetermined level.

A method of operating an electronically commutated motor with the motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• receiving a DC voltage for application to the motor;
• commutating the winding stages in response to a set of control signals by applying the DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• sensing the angular position of the rotatable assembly and providing a commutation signal indicative of a predetermined angular position of the rotatable assembly;
• providing the set of control signals to commutate the winding stages when the rotatable assembly reaches the predetermined angular position;
• and
• inhibiting the generation of the set of control signals when the motor current exceeds a predetermined maximum value, the inhibition being maintained until it is manually overriden.

A method of operating an electronically commutated motor with the motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• commutating the winding stages in response to a set of control signals by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly, each winding stage having at least two terminals, one of which is commonly connected to one terminal of each of the other winding stages and the DC voltage is applied to pairs of other terminals of the winding stages in at least one preselected sequence;
• supplying the control signals in a sequence in which for each commutation one of the winding stages which was energized before commutation remains energized after commutation and the other winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in the winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• and
• pulse width modulating the control signal associated with the winding stage which was commutated on until a time after commutation and shifting at that time to pulse width modulate the control signal associated with the winding stage which will be deenergized after the next commutation.

A method of operating an electronically commutated motor with the motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• a commutating the winding stages in response to a set of control signals by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly, the winding stages being connected together at one end whereby the DC voltage is applied to a pair of winding stages at a time, and wherein each winding stage has associated therewith first drive means for allowing the flow of current through its associated winding stage in a first direction in response to a first one of the control signals and second drive means for allowing the flow of current through its associated winding stage in the opposite direction in response to a second one of the control signals;
• supplying the control signals in a sequence in which for each commutation one of the winding stages which was energized before commutation remains energized after commutation and the other winding stage which was energized before commutation becomes deenergized after commutation, each winding stage remaining energized through two successive commutations unique to it and then becoming deenergized, the direction of current flow in the winding stage which remains energized after commutation being the same as the direction of current flow in that winding stage before commutation;
• and
• pulse width modulating upon commutation the control signal associated with the winding stage which remains energized by generating a drive selection signal every other commutation and in response to a first state of the drive selection signal shifting from modulating the control signals for the first drive means to modulating the control signals for the second drive means upon commutation and in response to a second state of the drive selection signal shifting from modulating the control signals for the second drive means to modulating the control signals for the first drive means upon commutation.

A method of operating an electronically commutated, two-speed motor with the motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

• commutating the winding stages in response to a set of control signals by applying a DC voltage thereto in at least one preselected sequence to cause rotation of the rotatable assembly;
• sensing a back emf signal indicative of the back emf condition of at least one winding;
• integrating a portion of the back emf signal and producing a commutation signal indicative of a predetermined angular position of the rotatable assembly, the integration occurring at a first rate when the motor is being operated at one speed and occurring at a second rate when the motor is being operated at the second speed, the rate of integration being determined by a speed control signal;
• and
• providing the set of control signals in response to the commutation signal to commutate the winding stages when the rotatable assembly reaches the predetermined angular position.