Abstract: An optocoupler circuit includes first and second resistors, an optocoupler, a reference circuit, and a comparator. The optocoupler includes a light source and a phototransistor. The light source is connected to form a first voltage divider with the first resistor. The phototransistor is connected to form a second voltage divider with the second resistor. The optocoupler transitions an output of the second voltage divider between first and second levels. Magnitudes of the first and second levels are greater than zero. The reference circuit is configured to output a reference voltage. The comparator includes a first input and a second input. The first input receives an output of the first voltage divider. The second input receives the reference voltage. An output of the comparator transitions between a third level and a fourth level based on a comparison between the output of the first voltage divider and the reference voltage.

Abstract: A system for controlling a capacity of a compressor includes a motor of the compressor including a main winding connected at a connection point to an auxiliary winding and a drive configured to control a speed of the motor. The system includes a first switch configured to selectively connect the main winding to either a first line voltage or a first output of the drive, a second switch configured to selectively connect the connection point to either a second line voltage or a second output of the drive, and a third switch configured to selectively connect the auxiliary winding to either a capacitor or a third output of the drive. The system includes a solenoid valve configured to selectively either operate in a first capacity or a second capacity. The system includes a control module configured to control the drive, the first switch, the second switch, and the third switch.

Abstract: A desired OFF period module is configured to determine a desired OFF period for a plurality of switches of a PFC circuit based on an input voltage and an output voltage. A blanking timer module is configured to output a blanking signal, set the blanking signal to a first state when a countdown timer is greater than zero, and set the blanking signal to a second state when the countdown timer reaches zero. A switching control module is configured to: transition a first switch of the plurality of switches from an ON state to an OFF state in response to (i) a measured current through an inductor of the PFC circuit being greater than a demanded current through the inductor and (ii) the blanking signal being in the second state; and maintain the first switch in the OFF state for the desired OFF period after the transition.

Abstract: A system for controlling a capacity of a compressor includes a motor of the compressor including a main winding connected at a connection point to an auxiliary winding and a drive configured to control a speed of the motor. The system includes a first switch configured to selectively connect the main winding to either a first line voltage or a first output of the drive, a second switch configured to selectively connect the connection point to either a second line voltage or a second output of the drive, and a third switch configured to selectively connect the auxiliary winding to either a capacitor or a third output of the drive. The system includes a solenoid valve configured to selectively either operate in a first capacity or a second capacity. The system includes a control module configured to control the drive, the first switch, the second switch, and the third switch.

Abstract: A system for controlling a capacity of a compressor includes a motor of the compressor including a main winding connected at a connection point to an auxiliary winding and a drive configured to control a speed of the motor. The system includes a first switch configured to selectively connect the main winding to either a first line voltage or a first output of the drive, a second switch configured to selectively connect the connection point to either a second line voltage or a second output of the drive, and a third switch configured to selectively connect the auxiliary winding to either a capacitor or a third output of the drive. The system includes a solenoid valve configured to selectively either operate in a first capacity or a second capacity. The system includes a control module configured to control the drive, the first switch, the second switch, and the third switch.

Abstract: An optocoupler circuit includes first and second resistors, an optocoupler, a reference circuit, and a comparator. The optocoupler includes a light source and a phototransistor. The light source is connected to form a first voltage divider with the first resistor. The phototransistor is connected to form a second voltage divider with the second resistor. The optocoupler transitions an output of the second voltage divider between first and second levels. Magnitudes of the first and second levels are greater than zero. The reference circuit is configured to output a reference voltage. The comparator includes a first input and a second input. The first input receives an output of the first voltage divider. The second input receives the reference voltage. An output of the comparator transitions between a third level and a fourth level based on a comparison between the output of the first voltage divider and the reference voltage.

Abstract: A control system for driving a motor of a compressor includes a microcontroller and a programmable logic device. The microcontroller is configured to generate a reference current value for a power factor correction (PFC) converter. The programmable logic device is configured to receive control messages from the microcontroller and, in response to data in a first control message, set a value into a timing register. The programmable logic device is configured to reverse a state of a power switch of the PFC converter between an on state and an off state in response to receiving a comparison signal indicating that a measured current in the PFC converter crossed the reference current value. The programmable logic device is configured to, subsequent to reversing the state of the power switch, wait for a period of time determined by the timing register and reverse the state of the power switch.

Abstract: A desired OFF period module is configured to determine a desired OFF period for a plurality of switches of a PFC circuit based on an input voltage and an output voltage. A blanking timer module is configured to output a blanking signal, set the blanking signal to a first state when a countdown timer is greater than zero, and set the blanking signal to a second state when the countdown timer reaches zero. A switching control module is configured to: transition a first switch of the plurality of switches from an ON state to an OFF state in response to (i) a measured current through an inductor of the PFC circuit being greater than a demanded current through the inductor and (ii) the blanking signal being in the second state; and maintain the first switch in the OFF state for the desired OFF period after the transition.

Abstract: A PFC circuit is provided. A first bridge rectifier receives an AC voltage. A power converter includes a switch and receives an output of the first bridge rectifier, converts the output to a first DC voltage, and supplies the first DC voltage to a DC bus to power a compressor. A second bridge rectifier receives the AC voltage and bypasses at least one of the first bridge rectifier, a choke and a diode of the PFC circuit to provide a rectified AC voltage out of the second bridge rectifier to the DC bus to power the compressor. A control module controls operation of a driver to transition the switch between open and closed states to adjust a second DC voltage on the DC bus, where the second DC voltage, depending on the AC and second DC voltages, is based on the first DC voltage or the rectified AC voltage.

Abstract: A power factor correction (PFC) system includes a desired OFF period module that determines a desired OFF period for a switch of a PFC circuit based on an input voltage to the PFC circuit and an output voltage of the PFC circuit. A switching control module transitions the switch from an ON state to an OFF state when a measured current through an inductor of the PFC circuit is greater than a demanded current through the inductor and maintains the switch in the OFF state for the desired OFF period after the transition from the ON state to the OFF state.

Abstract: An isolated temperature sensing system includes a thermistor that measures a temperature of a compressor system. An isolation circuit charges a capacitor, sets an output signal to a first state during charging of the capacitor, discharges the capacitor to the thermistor, and sets the output signal to a second state during discharging of the capacitor to the thermistor. The first state is different than the second state. A control module receives the output signal via an isolation barrier and determines the temperature of the compressor system based on a ratio of: (i) a first period that the output signal is in the first state to (ii) a second period that the output signal is in the second state.

Abstract: A circuit for driving a motor of a compressor includes a microcontroller that outputs a comparison signal in response to a value representative of a current in a power factor correction converter exceeding a reference value. A programmable logic device (PLD) receives control messages from the microcontroller. The PLD sets a value in an off-time register based on a control message from the microcontroller. The PLD controls the power switch according to the comparison signal and the off-time register.

Abstract: A circuit for driving a motor of a compressor includes a microcontroller that generates a reference current value for a power factor correction (PFC) converter. A programmable logic device (PLD) receives control messages from the microcontroller. The PLD sets a value in an off-time register based on a control message from the microcontroller. The PLD controls a power switch of the PFC converter to turn off in response to receiving a comparison signal indicating that a measured current in the PFC converter exceeds the reference current value. Subsequent to controlling the power switch to turn off, the PLD waits for a period of time determined by the off-time register before controlling the power switch to turn on.

Abstract: A drive includes an inverter power circuit that applies power to an electric motor of a compressor from a direct current (DC) voltage bus. A power factor correction (PFC) circuit outputs power to the DC voltage bus based on input alternating current (AC) power. The PFC circuit includes: (i) a switch having a first terminal, a second terminal, and a control terminal; (ii) a driver that switches the switch between open and closed states based on a control signal; (iii) an inductor that charges and discharges based on switching of the switch; and (iv) a circuit that outputs a signal indicating whether the switch is in the open state or the closed state based on a voltage across the first and second terminals of the switch.

Abstract: A drive includes an inverter power circuit that applies power to an electric motor of a compressor from a direct current (DC) voltage bus. A power factor correction (PFC) circuit outputs power to the DC voltage bus based on input alternating current (AC) power. The PFC circuit includes: (i) a switch having a first terminal, a second terminal, and a control terminal; (ii) a driver that switches the switch between open and closed states based on a control signal; (iii) an inductor that charges and discharges based on switching of the switch; and (iv) a circuit that outputs a signal indicating whether the switch is in the open state or the closed state based on a voltage across the first and second terminals of the switch.

Abstract: A PFC circuit is provided. A bridge rectification circuit receives an AC voltage and generates a rectified AC voltage. A power converter converts the rectified AC voltage to a first DC voltage, where the power converter includes a switch and supplies the first DC voltage to a DC bus to power a compressor. A current sensor detects an amount of current. A control module, while operating in a correction mode: based on the rectified AC voltage, a phase angle of the rectified AC voltage, a second DC voltage of the DC bus, or the detected amount of current, control operation of the switch to transition between operating in a high activity mode and an inactive or low activity mode; transition the switch between open and closed states while in the high and low activity modes; and maintain the power converter in an OFF state while in the inactive mode.

Abstract: A power factor correction (PFC) system includes a PFC circuit that receives an alternating current (AC) voltage and that, using a switch, generates a direct current (DC) voltage from the AC voltage. A zero crossing module determines a zero crossing of the AC voltage based on: a first voltage and a first time when the AC voltage transitioned from less than a first predetermined voltage to greater than the first predetermined voltage; and a second voltage and a second time when the AC voltage transitioned from less than a second predetermined voltage to greater than the second predetermined voltage. The first predetermined voltage is negative, and the second predetermined voltage is positive. A reference module, based on the zero crossing, generates a sinusoidal reference signal corresponding to the AC voltage in phase and frequency. A switching control module controls switching of the switch based on the sinusoidal reference signal.

Abstract: A power factor correction (PFC) system includes an error control module that determines a first current demand based on a difference between a desired direct current (DC) voltage and a measured DC voltage. A filter module applies a filter to the first current demand to produce a second current demand. A weighting module (i) based on the difference, determines first and second weighting values for the first and second current demands, respectively, (ii) determines a third current demand based on the first current demand and the first weighting value, and (iii) determines a fourth current demand based on the second current demand and the second weighting value. A current demand module determines a final current demand based on the third current demand and fourth current demand. A current control module controls switching of a switch of a PFC device based on the final current demand.

Abstract: A method of operating an electric motor is disclosed. The method includes: starting the electric motor in an open loop control mode; operating an estimator that estimates operating conditions of the electric motor; and, while the electric motor is in the open loop control mode, evaluating a first parameter of the estimator. The method further includes: in response to the evaluation of the first parameter, determining whether the estimator has converged; and in response to a determination that the estimator has not converged within a predetermined period of time after starting the electric motor, signaling a first fault condition.

Abstract: A circuit for driving a motor of a compressor includes a microcontroller, which includes an op-amp, a comparator, a first serial interface, and a first dedicated pin. The op-amp amplifies a value indicating current in a power factor correction converter, which includes a power switch. The comparator asserts a comparison signal in response to the amplified value exceeding a reference value. The comparison signal is output on the first dedicated pin. A programmable logic device (PLD) includes a second serial interface in communication with the first serial interface and a second dedicated pin. The comparison signal is received on the second dedicated pin and the PLD receives control messages from the microcontroller via the second serial interface. The PLD sets a value in an off-time register based on a control message from the microcontroller. The PLD controls the power switch according to the comparison signal and the off-time register.