System and methods for driving a blower with a motor

A heating, ventilating, and/or air conditioning (HVAC) system comprising:

• a heat exchanger for heating or cooling air;
• a blower for discharging heated or cooled air through a discharge air path to a space thereby to condition air in the space by changing its temperature;
• a temperature sensor positioned in the discharge air path remotely from the heat exchanger, said temperature sensor generating a temperature signal representative of the temperature of the air discharged to the space by the blower;
• a motor having first and second operating modes driving the blower at a speed or torque defined by a motor control signal thereby to control air flow rate of the HVAC system, said motor operating at a minimum speed or torque in the first operating mode and operating at a variable speed or torque greater than or equal to the minimum speed or torque in the second operating mode;
• and
• a control circuit generating the motor control signal in response to the temperature signal to cause the motor to operate in the first operating mode until the temperature of the discharged air as represented by the temperature signal reaches a reference temperature, said control circuit thereafter generating the motor control signal to cause the motor to operate in the second operating mode, said variable motor speed or torque of the second operating mode being a function of the difference between the temperature of the discharged air and the reference temperature, said motor maintaining the air flow rate of the HVAC system substantially constant in the first operating mode and increasing the air flow rate of the HVAC system as the temperature difference increases in the second operating mode.

A motor having first and second operating modes for driving a blower of a heating, ventilating, and/or air conditioning (HVAC) system, said blower discharging heated or cooled air through a discharge air path to a space thereby to condition air in the space by changing its temperature, said HVAC system having a temperature sensor positioned in the discharge air path, said temperature sensor generating a temperature signal representative of the temperature of the air discharged to the space by the blower, said motor comprising:

• a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, the stationary assembly including windings adapted to be energized in at least one preselected sequence, the rotatable assembly being in driving relation to the blower;
• power switching devices responsive to a motor control signal for selectively connecting a power supply to the windings in the preselected sequence to produce an electromagnetic field for rotating the rotatable assembly at a desired motor speed or torque thereby to control air flow rate of the HVAC system, said rotatable assembly rotating at a minimum speed or torque in the first operating mode and rotating at a variable motor speed or torque greater than or equal to the minimum speed or torque in the second operating mode;
• and
• a control circuit generating the motor control signal in response to the temperature signal to cause the motor to operate in the first operating mode until the temperature of the discharged air as represented by the temperature signal reaches a reference temperature, said control circuit thereafter generating the motor control signal to cause the motor to operate in the second operating mode, said variable motor speed or torque of the second operating mode being a function of the difference between the temperature of the discharged air and the reference temperature, said motor maintaining the air flow rate of the HVAC system substantially constant in the first operating mode and increasing the air flow rate of the HVAC system as the temperature difference increases in the second operating mode.

A method of operating a system for driving a blower of a heating, ventilating, and/or air conditioning (HVAC) system, said blower discharging heated or cooled air through a discharge air path to a space thereby to condition air in the space by changing its temperature, said method comprising:

• positioning a temperature sensor in the discharge air path for sensing the temperature of the air discharged to the space by the blower;
• generating a temperature signal representative of the sensed temperature of the air discharged by the blower;
• driving the blower with a motor having first and second operating modes and operating at a speed or torque defined by a motor control signal thereby to control air flow rate of the HVAC system, said motor operating at a minimum speed or torque in the first operating mode and operating at a variable speed or torque greater than or equal to the minimum speed or torque in the second operating mode;
• maintaining the air flow rate of the HVAC system substantially constant until the temperature of the discharged air as represented by the temperature signal reaches a reference temperature by generating the motor control signal to cause the motor to operate in the first operating mode;
• and
• thereafter increasing the air flow rate of the HVAC system as the difference between the temperature of the discharged air and the reference temperature increases by generating the motor control signal to cause the motor to operate in the second operating mode, said variable motor speed or torque of the second operating mode being a function of the temperature difference.

A method of operating a heating, ventilating, and/or air conditioning (HVAC) system, said HVAC system having a heat exchanger for heating or cooling air, a blower discharging the heated or cooled air through a discharge air path to a space thereby to condition air in the space by changing its temperature, said method comprising:

• positioning a temperature sensor in the discharge air path remotely from the heat exchanger for sensing the temperature of the air discharged to the space by the blower;
• generating a temperature signal representative of the sensed temperature of the air discharged to the space by the blower;
• driving the blower with a motor having first and second operating modes and operating at a speed or torque defined by a motor control signal thereby to control air flow rate of the HVAC system, said motor operating at a minimum speed or torque in the first operating mode and operating at a variable speed or torque greater than or equal to the minimum speed or torque in the second operating mode;
• maintaining the air flow rate of the HVAC system substantially constant until the temperature of the discharged air as represented by the temperature signal reaches a reference temperature by generating the motor control signal to cause the motor to operate in the first operating mode;
• and
• thereafter increasing the air flow rate of the HVAC system as the difference between the temperature of the discharged air and the reference temperature increases by generating the motor control signal to cause the motor to operate in the second operating mode said variable motor speed or torque of the second operating mode being a function of the temperature difference.

A method of operating a motor having first and second operating modes for driving a blower of a heating, ventilating, and/or air conditioning (HVAC) system, said blower discharging heated or cooled air through a discharge air path to a space thereby to condition air in the space by changing its temperature, said motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, the stationary assembly including windings adapted to be energized in at least one preselected sequence, the rotatable assembly being in driving relation to the blower, said method comprising:

• selectively connecting a power supply to the windings in the preselected sequence by switching power switching devices in response to a motor control signal to produce an electromagnetic field for rotating the rotatable assembly at a desired motor speed or torque thereby to control air flow rate of the HVAC system, said rotatable assembly rotating at a minimum speed or torque in the first operating mode and rotating at a variable motor speed or torque greater than or equal to the minimum speed or torque in the second operating mode;
• positioning a temperature sensor in the discharge air path for sensing the temperature of the air discharged to the space by the blower;
• generating a temperature signal representative of the sensed temperature of the air discharged by the blower;
• generating the motor control signal in response to the temperature signal to cause the motor to operate in the first operating mode until the temperature of the discharged air as represented by the temperature signal reaches a reference temperature, said motor operating in the first operating mode maintaining the air flow rate of the HVAC system substantially constant;
• and
• thereafter generating the motor control signal to cause the motor to operate in the second operating mode, said motor operating in the second operating mode increasing the air flow rate of the HVAC system as the difference between the temperature of the discharged air and the reference temperature increases, said variable motor speed or torque of the second operating mode being a function of the temperature difference.