Brushless and sensorless DC motor control system with locked and stopped rotor detection

A motor control system for controlling a brushless and sensorless DC motor system having a plurality of phase coils, comprising:

• a motor control integrated circuit having a plurality of motor driver outputs and a control input for operating said plurality of motor driver outputs, said plurality of motor driver outputs coupled to the plurality of phase coils;
• a fault detection circuit coupled with said control input and capable of detecting a plurality of electrical and nonelectrical fault conditions of the motor system, said fault detection circuit capable of providing a control signal to said control input to disable said plurality of motor driver outputs upon detection of at least one of said plurality of electrical and nonelectrical fault conditions;
• and
• a temperature sensing circuit coupled to said fault detection circuit.

A method for detecting faults in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils, comprising the steps of:

• providing a motor control integrated circuit having a plurality of power driver outputs coupled to the plurality of phase coils, and having a control input capable of selectively enabling the plurality of power driver outputs;
• momentarily and substantially simultaneously disabling all of said plurality of power driver outputs,
• detecting a motor system fault by measuring EMF on at least one of the plurality of phase coils while all of said plurality of power driver outputs are momentarily disabled;
• and
• switching the control input to disable all of the plurality of power driver outputs upon detecting a motor system fault indicated by measured EMF below a preset threshold to thereby stop motor operation.

A method for detecting faults in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils, comprising the steps of:

• providing a motor control integrated circuit having a plurality of power driver outputs coupled to the plurality of phase coils, and having a control input capable of selectively enabling the plurality of power driver outputs;
• detecting a motor system fault by measuring EMF on at least one of the plurality of phase coils;
• and
• switching the control input to disable the plurality of power driver outputs upon detecting a motor system fault indicated by excess, measured EMF below a preset threshold to thereby stop motor operation;
• wherein the step of detecting a motor system fault includes the steps of:
• measuring the temperature of a portion of the motor system;
• and
• determining a fault upon the measured temperature exceeding a preset threshold.

A method for detecting faults in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils, comprising the steps of:

• providing a motor control integrated circuit having a plurality of power driver outputs coupled to the plurality of phase coils, and having a control input capable of selectively enabling the plurality of power driver outputs;
• detecting a motor system fault by measuring EMF on at least one of the plurality of phase coils;
• and
• switching the control input to disable the plurality of power driver outputs upon detecting a motor system fault indicated by excess, measured EMF below a preset threshold to thereby stop motor operation;
• wherein the motor system includes a compressor driven by the motor, and wherein the step of detecting a motor system fault includes the steps of:
• determining a minimum motor speed below which the compressor may be damaged due to lack of adequate lubrication;
• measuring the motor speed;
• and
• determining a fault upon the measured motor speed being above or below the minimum motor speed.

A method for detecting faults in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils, comprising the steps of:

• providing a motor control integrated circuit having a plurality of power driver outputs coupled to the plurality of phase coils, and having a control input capable of selectively enabling the plurality of power driver outputs;
• detecting a motor system fault by measuring EMF on at least one of the plurality of phase coils;
• and
• switching the control input to disable the plurality of power driver outputs upon detecting a motor system fault indicated by excess, measured EMF below a preset threshold to thereby stop motor operation;
• wherein the motor system includes a compressor driven by the motor, and wherein the step of determining a motor system fault includes the steps of:
• determining a maximum motor speed above which compressor valve damage may occur;
• measuring the motor speed;
• and
• determining a fault upon the measured motor speed exceeding the maximum motor speed.

A method for detecting a locked or stopped rotor in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils driven by power driver outputs, comprising the steps of:

• momentarily and substantially simultaneously disabling all of the power driver outputs;
• then measuring the back EMF generated from the plurality of phase coils while all of the power driver outputs are momentarily disabled;
• and
• then enabling all of the power driver outputs after a time period dependent on the measured back EMF.

A method for detecting a locked or stopped rotor in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils driven by power driver outputs, comprising the steps of:

• disabling the power driver outputs;
• then measuring the back EMF generated from the plurality of phase coils;
• then enabling the power driver outputs after a time period dependent on the measured back EMF;
• if measured back EMF is above a preset threshold, setting the time period to zero;
• incrementing a counter each time measured back EMF is below the preset threshold;
• and
• upon the counter exceeding a preset limit, disabling the power driver outputs.

A method for detecting a locked or stopped rotor in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils driven by power driver outputs, comprising the steps of:

• disabling the power driver outputs;
• then measuring the back EMF generated from the plurality of phase coils;
• then enabling the power driver outputs after a time period dependent on the measured back EMF;
• measuring the temperature of a portion of the motor system;
• and
• upon the measured temperature exceeding a threshold, disabling the power driver outputs.

A method for detecting a locked or stopped rotor in a motor control system for a brushless and sensorless DC motor system having a plurality of phase coils driven by power driver outputs, comprising the steps of:

• disabling the power driver outputs;
• then measuring the back EMF generated from the plurality of phase coils;
• and
• then enabling the power driver outputs after a time period dependent on the measured back EMF;
• wherein the motor system includes a compressor driven by the motor, and further comprising the steps of:
• determining a minimum motor speed below which the compressor may be damaged due to lack of adequate lubrication;
• determining the motor speed;
• and
• upon the motor speed being below the minimum motor speed, disabling the power driver outputs.

A fluid handling system, comprising:

• a pump;
• a brushless DC motor for driving said pump, said motor having a plurality of phase coils;
• and
• a motor control system coupled to said motor, said motor controller system including:
• a motor control circuit having at least one motor driver output coupled to said plurality of phase coils;
• and
• a microcontroller having an AID converter coupled to at least one of said plurality of phase coils and having software enabling said microcontroller to provide an output signal coupled to said motor control circuit for momentarily disabling said at least one motor driver output, said microcontroller capable of measuring a voltage level of back EMF generated in said at least one of said plurality of phase coils upon said at least one motor driver output being disabled.

An actuator control system for controlling a sensorless DC actuator having a plurality of phase coils, comprising:

• an actuator control integrated circuit having a control input and a plurality of driver outputs, said control input adapted for selectively disabling said driver outputs, said driver outputs coupled to the plurality of phase coils;
• and
• a voltage measuring circuit coupled with the plurality of phase coils and providing a control signal coupled with said control input;
• said voltage measuring circuit capable of selectively switching the state of said control input to momentarily and substantially simultaneously disable all of said driver outputs;
• said voltage measuring circuit measuring a voltage received from the plurality of phase coils upon said voltage measuring circuit momentarily providing said control signal to substantially simultaneously disable all of said driver outputs,
• said voltage measuring circuit further providing said control signal upon said received voltage being below a preset threshold.