Electronically commutated motor for driving a compressor

A system for driving a compressor of a refrigeration system comprising:

• a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly being in driving relation to the compressor;
• power switching devices responsive to a commutation signal for selectively connecting a power supply to the windings in the preselected sequence to produce an electromagnetic field for rotating the rotatable assembly;
• and
• an application specific integrated circuit (ASIC) providing the commutation signal for controlling commutation of the motor thereby to operate the motor at a selected speed, said ASIC comprising:
• a fault detector for detecting overcurrent and/or underspeed conditions of the motor;
• a protection circuit for disabling the motor in response to the detector detecting at least one of the conditions for a first period of time;
• an inhibitor circuit for preventing disablement of the motor by the protective circuit during a second period of time immediately following starting of the motor;
• a reset circuit for resetting the detector after a third period of time to permit enablement of the motor after disablement thereof by the protection circuit;
• and
• a timer for timing the first, second and third periods of time.

A refrigeration system comprising:

• a compressor for circulating a refrigerant through an evaporator;
• a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly being in driving relation to the compressor;
• power switching devices responsive to a commutation signal for selectively connecting a power supply to the windings in the preselected sequence to produce an electromagnetic field for rotating the rotatable assembly;
• and
• an application specific integrated circuit (ASIC) providing the commutation signal for controlling commutation of the motor thereby to operate the motor at a selected speed, said ASIC comprising:
• a fault detector for detecting overcurrent and/or underspeed conditions of the motor;
• a protection circuit for disabling the motor in response to the detector detecting at least one of the conditions for a first period of time;
• an inhibitor circuit for preventing disablement of the motor by the protective circuit during a second period of time immediately following starting of the motor;
• a reset circuit for resetting the detector after a third period of time to permit enablement of the motor after disablement thereof by the protection circuit;
• and
• a timer for timing the first, second and third periods of time.

A system for driving a rotatable component comprising:

• a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly being in driving relation to the component;
• power switching devices responsive to a commutation signal for selectively connecting a power supply to the windings in the preselected sequence to produce an electromagnetic field for rotating the rotatable assembly;
• and
• an application specific integrated circuit (ASIC) providing the commutation signal for controlling commutation of the motor thereby to operate the motor at a selected speed, said ASIC comprising:
• a fault detector for detecting overcurrent and/or underspeed conditions of the motor;
• a protection circuit for disabling the motor in response to the detector detecting at least one of the conditions for a first period of time;
• an inhibitor circuit for preventing disablement of the motor by the protective circuit during a second period of time immediately following starting of the motor;
• a reset circuit for resetting the detector after a third period of time to permit enablement of the motor after disablement thereof by the protection circuit;
• and
• a timer for timing the first, second and third periods of time.

A system for driving a rotatable component at one or more speeds comprising:

• a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly being in driving relation to the component;
• a speed selector for providing a speed select signal representative of a selected one of the speeds, said motor driving the compressor at a desired speed corresponding to the speed select signal;
• power switching devices responsive to a commutation signal for selectively connecting a power supply to the windings in the preselected sequence to produce an electromagnetic field for rotating the rotatable assembly;
• and
• an application specific integrated circuit (ASIC) connected between the speed selector and the motor, said ASIC including a position sensor circuit providing a position signal representative of a position of the rotatable assembly and including a commutation circuit generating the commutation signal in response to the speed select signal and the position signal for controlling commutation of the motor thereby to operate the motor at the selected speed as represented by the speed select signal, said ASIC further including an undervoltage detector for detecting an undervoltage condition of the ASIC and disabling the motor in response thereto.

A method of protecting a motor driving a component, said motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly in driving relation to the component, said system further comprising an application specific integrated circuit (ASIC) connected to the motor, said method comprising the steps of:

• detecting overcurrent, underspeed and/or undervoltage conditions of the motor with the ASIC;
• disabling the motor in response to the ASIC detecting at least one of the conditions for a first period of time;
• preventing disablement of the motor during a second period of time immediately following starting of the motor;
• and
• resetting the ASIC for detecting overcurrent, underspeed and/or undervoltage conditions of the motor after a third period of time to permit enablement of the motor after disablement thereof.

A method of operating a system for driving a compressor of a refrigeration system, said system comprising a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly in driving relation to the compressor, said system further comprising an application specific integrated circuit (ASIC) connected to the motor, said method comprising the steps of:

• selectively connecting a power supply to the windings in the preselected sequence with power switching devices responsive to a commutation signal to produce an electromagnetic field for rotating the rotatable assembly;
• providing the commutation signal with the ASIC to control commutation of the motor thereby operating the motor at a selected speed;
• detecting overcurrent, underspeed and/or undervoltage conditions of the motor with the ASIC;
• disabling the motor in response to the ASIC detecting at least one of the conditions for a first period of time;
• preventing disablement of the motor during a second period of time immediately following starting of the motor;
• resetting the ASIC for detecting overcurrent, underspeed and/or undervoltage conditions of the motor after a third period of time to permit enablement of the motor after disablement thereof.

A method of operating a refrigeration system, said refrigeration system having a compressor for circulating refrigerant through an evaporator and a motor for driving the compressor, said motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly in driving relation to the compressor, said system further comprising an application specific integrated circuit (ASIC) connected to the motor, said method comprising the steps of:

• selectively connecting a power supply to the windings in the preselected sequence with power switching devices responsive to a commutation signal to produce an electromagnetic field for rotating the rotatable assembly;
• providing the commutation signal with the ASIC to control commutation of the motor thereby operating the motor at a selected speed;
• detecting overcurrent, underspeed and/or undervoltage conditions of the motor with the ASIC;
• disabling the motor in response to the ASIC detecting at least one of the conditions for a first period of time;
• preventing disablement of the motor during a second period of time immediately following starting of the motor;
• resetting the ASIC for detecting overcurrent, underspeed and/or undervoltage conditions of the motor after a third period of time to permit enablement of the motor after disablement thereof.

A method of operating a system for driving a rotatable component, said system comprising a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly in driving relation to the component, said system further comprising an application specific integrated circuit (ASIC) connected to the motor, said method comprising the steps of:

• selectively connecting a power supply to the windings in the preselected sequence with power switching devices responsive to a commutation signal to produce an electromagnetic field for rotating the rotatable assembly;
• providing the commutation signal with the ASIC to control commutation of the motor thereby operating the motor at a selected speed;
• detecting overcurrent, underspeed and/or undervoltage conditions of the motor with the ASIC;
• disabling the motor in response to the ASIC detecting at least one of the conditions for a first period of time;
• preventing disablement of the motor during a second period of time immediately following starting of the motor;
• resetting the ASIC for detecting overcurrent, underspeed and/or undervoltage conditions of the motor after a third period of time to permit enablement of the motor after disablement thereof.

A method of operating a system for driving a rotatable component at one or more speeds, said system comprising a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, said stationary assembly including windings adapted to be commutated in at least one preselected sequence, said rotatable assembly in driving relation to the component, said system further comprising an application specific integrated circuit (ASIC) connected to the motor, said method comprising the steps of:

• providing a speed select signal representative of a selected one of the speeds, said motor driving the compressor at a desired speed corresponding to the speed select signal;
• providing a position signal representative of a position of the rotatable assembly;
• inputting the speed select signal and the position signal to the ASIC;
• generating a commutation signal via the ASIC in response to the speed select signal and the position signal for controlling commutation of the motor thereby to operate the motor at the selected speed as represented by the speed select signal;
• selectively connecting a power supply to the windings in the preselected sequence with power switching devices responsive to the commutation signal to produce an electromagnetic field for rotating the rotatable assembly;
• detecting an undervoltage condition of the ASIC;
• and
• disabling the motor in response to the detected undervoltage condition.