Control system, electronically commutated motor system, draft inducer apparatus and method

A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, and which control system is adapted to receive control pulses having a duty cycle representing a desired operating torque for the motor, the control system for use with a commutating circuit for controlling power switching devices for applying the voltage to one or more of the winding stages at a time having a duty cycle which is a function of a pulsed signal and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly, the control system comprising:

• means for generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating means adapted to supply the PWM series of pulses to the commutating circuit as the pulsed signal;
• means for comparing the applied voltage to a reference voltage;
• and
• means, responsive to the means for comparing, for increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage and for decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage whereby the operating speed of the motor is a function of the duty cycle of the control pulses and is substantially independent of variations in the magnitude of the applied voltage.

A control system for power switching devices of an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having rotatable assembly, and which control system is adapted to receive control pulses having a duty cycle representing a desired operating torque for the motor, the control system comprising:

• means for controlling the power switching devices to apply a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• means responsive to the motor current for generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating means adapted to supply the PWM series of pulses to the controlling means as the pulsed signal;
• means for comparing the applied voltage to a reference voltage;
• and
• means, responsive to the means for comparing, for increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage and for decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage whereby the operating torque of the motor is a function of the duty cycle of the control pulses and is substantially independent of variations in the magnitude of the applied voltage.

A control system for power switching devices of an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to applications of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, and which control system is adapted to receive control pulses having a duty cycle representing a desired operating speed for the motor, the control system comprising:

• means for controlling the power switching devices to apply a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• means for generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating means adapted to supply the PWM series of pulses to the controlling means as the pulsed signal;
• means for comparing the applied voltage to a reference voltage;
• and
• means, responsive to the means for comparing, for increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage and for decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage whereby the operating speed of the motor is a function of the duty cycle of the control pulses and is substantially independent of variations in the magnitude of the applied voltage.

A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, which control system is responsive to a motor control apparatus adapted to control the motor by generating control pulses having a duty cycle which is a function of a desired operating torque for the motor and the speed of the motor, the control system comprising:

• means for applying a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• means responsive to the motor current for generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating means adapted to supply the PWM series of pulses to the applying means as the pulsed signal;
• and
• means for providing a tachometer signal representative of the motor speed to the motor control apparatus.

A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, which control system is responsive to a motor control apparatus adapted to control the motor by generating control pulses having a duty cycle which is a function of a desired operating torque for the motor and the speed of the motor, the control system comprising:

• means for applying a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• means for varying the duty cycle of the applied voltage as an inverse function of the magnitude of the applied voltage;
• means for generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating means adapted to supply the PWM series of pulses to the applying means as the pulsed signal;
• and
• means for providing a tachometer signal representative of the motor speed to the motor control apparatus.

A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current and further having a rotatable assembly, and which control system is adapted to receive control pulses having a duty cycle representing a desired operating torque or speed for the motor, the control system being adapted for use with a commutating circuit for applying a voltage to one or more of the winding stages at a time in accordance with a pulsed signal and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly, the control system comprising:

• means for selecting the motor current or the motor voltage as a control parameter said selecting means, including means for sensing the motor current and means for providing a reference;
• means responsive to the selected motor operating parameter for generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating means adapted to supply the PWM series of pulses to the commutating circuit as the pulsed signal whereby the torque of the motor is a function of the duty cycle of the control pulses when the motor current is selected as the control parameter and the speed of the motor is a function of the duty cycle of the control pulses when the motor voltage is selected as the control parameter.

Draft inducer apparatus for use with a combustion chamber having an exhaust outlet comprising:

• a fan for moving air through the exhaust outlet and thereby to induce a draft in the combustion chamber;
• an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet rotor coupled to said fan and adapted to rotate in response to the magnetic poles established by said winding stages;
• means for generating a pulse width modulated (PWM) series of pulses having a duty cycle representing a desired torque or speed of the motor;
• power switching devices for applying a voltage to one or more of said winding stages at a time;
• [and]
• means for controlling said power switching devices in accordance with the PWM series of pulses and commutating said winding stages in a preselected sequence to rotate said permanent magnet rotor and said fan;
• and sensor means for sensing pressure within the exhaust outlet, said means for generating further comprising means connected to said sensor means for generating the PWM series of pulses with a duty cycle varying as a function of the sensed pressure.

Draft inducer apparatus for use with a combustion chamber having an exhaust outlet, comprising:

• a fan for moving air through the exhaust outlet and thereby to induce a draft in the combustion chamber;
• an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet [motor] rotor coupled to said fan and adapted to rotate in response to the magnetic poles established by said winding stages;
• means for providing a tachometer signal representative of the motor speed;
• storage means for storing a speed/torque profile of the motor;
• means, responsive to said means for providing a tachometer signal and said storage means, for generating a pulse width modulated (PWM) series of pulses having a duty cycle varying as a function of the motor speed/torque profile and the tachometer signal;
• power switching devices for applying a voltage to one or more of said winding stages at a time;
• means for controlling said power switching devices in accordance with the PWM series of pulses and commutating said winding stages in a preselected sequence to rotate said permanent magnet rotor and said fan.

A control method for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a rotatable assembly, and which control method is responsive to control pulses having a duty cycle representing a desired operating torque for the motor, the control method for use with a commutating circuit for controlling power switching devices for applying the voltage to one or more of the winding stages at a time having a duty cycle which is a function of a pulsed signal and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly, the control method comprising the steps of:

• generating a response to the motor current a pulse width modulated (PWM) series of pulses [having a pulse repetition rat] having a duty cycle which is a function of the duty cycle of the control pulses, the generating step adapted to supply the PWM series of pulses to the commutating circuit as the pulsed signal;
• comparing the applied voltage to a reference voltage;
• increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage;
• and
• decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage whereby the operating torque of the motor is a function of the duty cycle of the control pulses and is substantially independent of variations in the magnitude of the applied voltage.

A control method for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, and which control method is responsive to control pulses having a duty cycle representing a desired operating torque for the motor, the control method for use with a commutating circuit for controlling power switching devices for applying the voltage to one or more of the winding stages at a time having a duty cycle which is a function of a pulsed signal and for commutating the winding stages in a preselected sequence to rotate the rotatable assembly, the control method comprising the steps of:

• generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating step adapted to supply the PWM series of pulses to the commutating circuit as the pulsed signal;
• comparing the applied voltage to a reference voltage;
• increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage;
• and
• decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage whereby the operating speed of the motor is a function of the duty cycle and is substantially independent of variations in the magnitude of the applied voltage.

A control method for power switching devices of an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, and which control method is responsive to control pulses having a duty cycle representing a desired operating torque for the motor, the control method comprising the steps of:

• controlling the power switching devices to apply a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time;
• commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• generating in response to the motor current a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating step adapted to supply the PWM series of pulses as the pulsed signal;
• comparing the applied voltage to a reference voltage;
• increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage;
• and
• decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage whereby the operating torque of the motor is a function of the duty cycle of the control pulses and is substantially independent of variations in the magnitude of the applied voltage.

A control method for power switching devices of an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, and which control method is responsive to control pulses having a duty cycle representing a desired operating speed for the motor, the control method comprising the steps of:

• controlling the power switching devices to apply a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time;
• commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating step adapted to supply the PWM series of pulses as the pulsed signal;
• comparing the applied voltage to a reference voltage;
• increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage;
• and
• decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage whereby the operating speed of the motor is a function of the duty cycle of the control pulses and is substantially independent of variations in the magnitude of the applied voltage.

A control method for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, and which control method is responsive to a motor control apparatus adapted to control the motor by generating control pulses having a duty cycle which is a function of a desired operating torque for the motor and the speed of the motor, the control method comprising the steps of:

• applying a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time;
• storing a speed/torque profile of the motor;
• commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• generating, in response to the motor current and the motor speed, a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating step adapted to supply the PWM series of pulses as the pulsed signal;
• providing a tachometer signal representative of the motor speed to the motor control apparatus;
• and
• wherein the generating step is responsive to the storing step and the providing step for generating the PWM series of pulses with a duty cycle varying as a function of the motor speed/torque profile and the tachometer signal.

A control method for an electronically commutated motor having a stationary assembly with a plurality of winding stages for carrying a motor current in response to application of a voltage having a magnitude subject to variations, the motor further having a rotatable assembly, and which control method is responsive to a motor control apparatus adapted to control the motor by generating control pulses having a duty cycle which is a function of a desired operating torque for the motor and the speed of the motor, the control method comprising the steps of:

• applying a voltage having a duty cycle which is a function of a pulsed signal to one or more of the winding stages at a time;
• commutating the winding stages in a preselected sequence to rotate the rotatable assembly;
• varying the duty cycle of the applied voltage as an inverse function of the magnitude of the applied voltage;
• generating a pulse width modulated (PWM) series of pulses having a duty cycle which is a function of the duty cycle of the control pulses, the generating step adapted to supply the PWM series of pulses as the pulsed signal;
• and
• providing a tachometer signal representative of the motor speed to the motor control apparatus.

Method of inducing a draft in a combustion chamber having an exhaust outlet including a fan for moving air through the exhaust outlet and thereby to induce a draft in the combustion chamber and an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet rotor coupled to said fan and adapted to rotate in response to the magnetic poles established by said winding stages;

• said method comprising the steps of:
• generating a pulse width modulated (PWM) series of pulses having a duty cycle representing a desired torque or speed of the motor;
• applying a voltage to one or more of said winding stages at a time by use of power switching devices;
• controlling the power switching devices in accordance with the PWM series of pulses;
• commutating said winding stages in a preselected sequence to rotate said permanent magnet rotor and said fan;
• comparing the applied voltage to a reference voltage;
• increasing the duty cycle of the PWM series of pulses as a function of decreases in the applied voltage;
• and
• decreasing the duty cycle of the PWM series of pulses as a function of increases in the applied voltage.

Method of inducing a draft in combustion chamber having an exhaust outlet including a fan for moving air through the exhaust outlet and thereby to induce a draft in the combustion chamber and an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet rotor coupled to said fan and adapted to rotate in response to the magnetic poles established by said winding stages;

• said method comprising the steps of:
• providing a tachometer signal representative of the motor speed;
• storing a speed/torque profile of the motor;
• generating a pulse width modulated (PWM) series of pulses having a duty cycle varying as a function of the motor speed/torque profile and the tachometer signal;
• applying a voltage to one or more of said winding stages at a time in accordance with the PWM series of pulses;
• and
• commutating said winding stages in a preselected sequence to rotate said permanent magnet rotor and said fan.

A system for driving a rotatable component comprising:

• an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet rotor adapted to be coupled to said rotatable component and adapted to rotate in response to the magnetic poles established by said winding stages;
• means for providing a tachometer signal representative of the motor speed;
• storage means for storing a speed/torque profile of the motor;
• means, responsive to said means for providing a tachometer signal and said storage means, for generating a pulse width modulated (PWM) series of pulses having a duty cycle varying as a function of the motor speed/torque profile and the tachometer signal;
• power switching devices for applying a voltage to one or more of said winding stages at a time;
• and
• means for controlling said power switching devices in accordance with the PWM series of pulses and commutating said winding stages in a preselected sequence to rotate said permanent magnet rotor and said rotatable component.

Method of driving a rotatable component by an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet rotor coupled to said rotatable component and adapted to rotate in response to the magnetic poles established by said winding stages;

• said method comprising the steps of:
• providing a tachometer signal representative of the motor speed;
• storing a speed/torque profile of the motor;
• generating a pulse width modulated (PWM)series of pulses having a duty cycle varying as a function of the motor speed/torque profile and the tachometer signal;
• applying a voltage to one or more of said winding stages at a time in accordance with the PWM series of pulses;
• and
• commutating said winding stages in a preselected sequence to rotate said permanent magnet rotor and said rotatable component.