Electronically commutated motor for driving a compressor

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 to the stationary assembly, the rotatable assembly in driving relation to the compressor for driving the compressor at one or more preset speeds;
• means for generating a speed select signal representative of a selected one of the preset speeds, the motor driving the compressor at a desired speed corresponding to the speed select signal;
• and
• an application specific integrated circuit (ASIC) connected between the speed select signal generating means and the motor and including a circuit for generating a position signal representative of a position of the rotatable assembly, the ASIC receiving and responsive to the speed select signal and the position signal for generating a commutation signal for controlling commutation of the motor thereby to operate the motor at the selected preset speed as represented by the speed select signal;
• and
• power switching devices responsive to the 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.

A method of operating a system for driving a compressor of a refrigeration system at one or more preset speeds, said system comprising a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, the 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:

• generating a speed select signal representative of a selected one of the preset speeds, said motor driving the compressor at a desired speed corresponding to the speed select signal;
• generating a position signal representative of a position of the rotatable assembly;
• inputting the speed select signal to the ASIC, said ASIC being responsive to the speed select signal;
• generating a commutation reference 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 preset speed as represented by the speed select signal;
• and
• selectively connecting a power supply to the windings in the preselected sequence by switching power switching devices in response to the commutation reference signal to produce an electromagnetic field for rotating the rotatable assembly.

A system for driving a component at one or more preset 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;
• means for generating a speed select signal representative of a selected one of the preset speeds, said motor driving the component at a desired speed corresponding to the speed select signal;
• and
• an application specific integrated circuit (ASIC) connected between the speed select signal generating means and the motor, said ASIC including a circuit for generating a position signal representative of a position of the rotatable assembly, said ASIC further including means, receiving and responsive to the speed select signal and the position signal, for generating a commutation signal for controlling commutation of the motor thereby to operate the motor at the selected preset speed as represented by the speed select signal;
• and
• power switching devices responsive to the 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.

A method of operating a system for driving a component at one or more preset speeds, said system comprising a motor having a stationary assembly and a rotatable assembly in magnetic coupling relation thereto, the 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:

• generating a speed select signal representative of a selected one of the preset speeds, said motor driving the component at a desired speed corresponding to the speed select signal;
• generating a position signal representative of a position of the rotatable assembly;
• inputting the speed select signal to the ASIC, said ASIC being responsive to the speed select signal;
• generating a commutation reference 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 preset speed as represented by the speed select signal;
• and
• selectively connecting a power supply to the windings in the preselected sequence by switching power switching devices in response to the commutation signal to produce an electromagnetic field for rotating the rotatable assembly.

A system for driving a compressor of a refrigeration system at one or more preset speeds, said system comprising:

• a 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 compressor;
• a speed selection circuit for generating a speed select signal representative of one of the preset speeds, said motor driving the compressor at a desired speed corresponding to the speed select signal;
• an application specific integrated circuit (ASIC) connected between the speed selection circuit and the motor, said ASIC including a commutation circuit, receiving and responsive to the speed select signal, for generating a commutation signal to control commutation of the motor thereby to operate the motor at the desired speed;
• and
• an override circuit, including a switch for connecting a line-referenced ac voltage to the ASIC, for generating an override signal overriding the speed select signal, said ASIC receiving and responsive to the override signal for generating a high speed commutation reference signal corresponding to operation of the compressor at a maximum speed, the commutation signal being a function of the high speed commutation reference signal whereby the motor drives the compressor at the maximum speed when the ASIC receives the override signal.

A system for driving a compressor of a refrigeration system at one or more preset 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 energized in at least one preselected sequence, said rotatable assembly being in driving relation to the compressor;
• a speed selection circuit for generating a speed select signal representative of one of the preset speeds, said motor driving the compressor at a desired speed corresponding to the speed select signal;
• an application specific integrated circuit (ASIC) connected between the speed selection circuit and the motor, said ASIC including a commutation circuit, receiving and responsive to the speed select signal, for generating a commutation signal for controlling commutation of the motor thereby to operate the motor at the desired speed;
• and
• an override circuit for generating an ac voltage signal overriding the speed select signal, said ASIC receiving the ac voltage signal and generating a high speed commutation reference signal corresponding to operation of the compressor at a maximum speed in response to detecting a positive waveform portion of the ac voltage signal, the commutation signal being a function of the high speed commutation reference signal whereby the motor drives the compressor at the maximum speed when the ASIC receives the ac voltage signal.

A system for driving a compressor of a refrigeration system at one or more preset 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 energized in at least one preselected sequence, said rotatable assembly being in driving relation to the compressor;
• a speed selection circuit for generating a speed select signal representative of one of the preset speeds, said motor driving the compressor at a desired speed corresponding to the speed select signal;
• an application specific integrated circuit (ASIC) connected between the speed selection circuit and the motor, said ASIC including a position sensing circuit for sensing a back electromotive force (EMF) voltage in the windings and for detecting zero crossings of the difference between the back EMF voltage in a selected winding as compared to a reference level, the position sensing circuit generating a position signal representative of a position of the rotatable assembly relative to the detected zero crossings of the sensed back EMF voltage, said ASIC further including a commutation circuit responsive to the speed select signal and the position signal for generating a commutation signal to control commutation of the motor thereby to operate the motor at the desired speed;
• and
• power switching devices responsive to the 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.

A method of operating a system for driving a compressor of a refrigeration system at one or more preset 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 energized in at least one preselected sequence, said rotatable assembly being 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:

• generating a speed select signal representative of one of the preset speeds, said motor driving the compressor at a desired speed corresponding to the speed select signal;
• inputting the speed select signal to the ASIC, said ASIC being responsive to the speed select signal;
• and
• generating a commutation signal via the ASIC in response to the speed select signal to control commutation of the motor thereby to operate the motor at the desired speed;
• sensing a back electromotive force (EMF) voltage in the windings;
• detecting zero crossings of the difference between the back EMF voltage in a selected winding as compared to a reference level;
• generating a position signal representative of a position of the rotatable assembly relative to the detected zero crossings of the sensed back EMF voltage;
• generating a commutation signal in response to the commutation signal and the speed select signal for controlling commutation of the motor thereby to operate the motor at the desired speed;
• and
• selectively connecting a power supply to the windings in the preselected sequence by switching power switching devices in response to the commutation signal to produce an electromagnetic field for rotating the rotatable assembly.