Abstract:
Un sistema incluye un compresor que incluye una carcasa que aloja un mecanismo de compresión impulsado por un motor eléctrico en un estado encendido y no impulsado por el motor eléctrico en un estado apagado. El sistema también incluye un convertidor de frecuencia variable que acciona el motor eléctrico en el estado encendido variando una frecuencia de un voltaje suministrado al motor eléctrico y suministra corriente eléctrica a un estator del motor eléctrico en el estado apagado para calentar el compresor.
Abstract:
A power factor correction (PFC) system includes a direct current (DC) module, an error control module, an offset module, and a duty cycle control module. The DC module determines an average current value based on a plurality of current values over at least one cycle of an input alternating current (AC) line signal of the PFC system. The error control module generates an error signal based on the average current value. The offset module offsets a desired instantaneous current based on the error signal. The duty cycle control module controls at least one duty cycle of switches of the PFC system based on the offset desired instantaneous current.
Abstract:
A control system for a motor includes a pulse-width modulation module, a pulse skip determination module, and a duty cycle adjustment module. The pulse-width modulation module generates three duty cycle values based on three voltage requests, respectively. A plurality of solid-state switches control three phases of the motor in response to the three duty cycle values, respectively. The pulse skip determination module generates a pulse skip signal. The duty cycle adjustment module selectively prevents the plurality of solid-state switches from switching during intervals specified by the pulse skip signal.
Abstract:
A controller includes a voltage determination module, a bus voltage command module, and a power factor correction (PFC) control module. The voltage determination module determines a desired direct current (DC) bus voltage for a DC bus electrically connected between a PFC module and an inverter power module that drives a compressor motor. The voltage determination module determines the desired DC bus voltage based on at least one of torque of the compressor motor, speed of the compressor motor, output power of the inverter power module, and drive input power. The bus voltage command module determines a commanded bus voltage based on the desired DC bus voltage. The PFC control module controls the PFC module to create a voltage on the DC bus that is based on the commanded bus voltage.
Abstract:
A first rectifier diode is electrically connected between a first input terminal where an alternating current (AC) power is received and a first output terminal where a direct current (DC) power is output. A second rectifier diode is electrically connected between the first input terminal and a second output terminal. The first and second rectifier diodes rectify first and second portions of the AC power into the DC power, respectively. When switching of a plurality of power factor correction (PFC) switches is enabled, the plurality of PFC switches increases a voltage of the DC power to greater than a peak voltage of the AC power. An inductor is electrically connected between a second input terminal and two of the plurality of PFC switches. When the switching is disabled, first and second bypass diodes provide a current path past the plurality of PFC switches and the inductor.
Abstract:
A power factor correction (PFC) system includes a period determination module, a frequency generation module, an angle generation module, a signal generation module, and an angle correction module. The period determination module determines a period of an input alternating current (AC) line signal based on a time between rising edges of the input AC line signal. The frequency generation module generates a frequency based on the period. The angle generation module generates an angle based on the frequency. The signal generation module generates a sinusoidal reference signal based on the frequency and an adjusted angle. The angle correction module generates the adjusted angle based on the angle and based on a comparison of a falling edge of the sinusoidal reference signal, the period, and a rising edge of the input AC line signal.
Abstract:
A system includes a compressor having a shell housing a compression mechanism driven by an electric motor in an on state and not driven by the electric motor in an off state. The system also includes a variable frequency drive that drives the electric motor in the on state by varying a frequency of a voltage delivered to the electric motor and that supplies electric current to a stator of the electric motor in the off state to heat the compressor.
Abstract:
A power factor correction (PFC) system includes an adjustment module, a compensation module, and a duty cycle control module. The adjustment module generates N time advances based on N predetermined time advances and (N−1) time advance adjustments, wherein N is an integer greater than zero. The compensation module generates N compensated versions of an input alternating current (AC) line signal by predicting ahead of the input AC line signal using a gradient of a sinusoidal reference signal and the N time advances, respectively, wherein the sinusoidal reference signal is synchronized with the input AC line signal in phase and frequency. The duty cycle control module generates PFC duty cycles based on the N compensated versions of the input AC line signal.