Abstract: Described herein are methods, systems, and apparatuses for determining sag in a signal. In one example, a method of tracking sag in a signal includes, when in an initial state, monitoring for when the signal transitions to a sag state based at least on an output of a tracking filter. In response to the signal transitioning to the sag state, increasing a bandwidth of the tracking filter and, when in the sag state, monitoring for when the signal transitions to a recovering state. The method further includes, in response to the signal transitioning to the recovering state, decreasing the bandwidth of the tracking filter.

Abstract: Methods and systems are disclosed for detecting capacitor degradation in an input filter of an active front end power conversion system in which voltage and current sensing is performed to determine sequence component impedance asymmetry to detect filter capacitor degradation according to the value of an off-axis admittance matrix component for Delta or Y-connected filter capacitor banks without sensitivity to voltage unbalance, and with the capability to identify particular degraded capacitor locations based on individual impedance values.

Abstract: A double fed induction generator (DFIG) converter method are presented in which rotor side current spikes are attenuated using series-connected damping resistance in response to grid fault occurrences or grid fault clearances.

Abstract: Described herein are methods, systems, and apparatuses for determining sag in a signal. In one example, a method of tracking sag in a signal includes, when in an initial state, monitoring for when the signal transitions to a sag state based at least on an output of a tracking filter. In response to the signal transitioning to the sag state, increasing a bandwidth of the tracking filter and, when in the sag state, monitoring for when the signal transitions to a recovering state. The method further includes, in response to the signal transitioning to the recovering state, decreasing the bandwidth of the tracking filter.

Abstract: Methods and systems are disclosed for detecting capacitor degradation in an input filter of an active front end power conversion system in which voltage and current sensing is performed to determine sequence component impedance asymmetry to detect filter capacitor degradation according to the value of an off-axis admittance matrix component for Delta or Y-connected filter capacitor banks without sensitivity to voltage unbalance, and with the capability to identify particular degraded capacitor locations based on individual impedance values.

Abstract: The present invention relates generally to systems and methods for detecting ground faults (i.e., line-to-ground faults) in motor drive systems. In particular, the embodiments described herein include a common mode choke of a motor drive system having additional (i.e., secondary) turns wound around a core of the common mode choke. These secondary turns are in addition to and separate from a plurality of sets of primary turns wound around the core of the common mode choke, each set of primary turns corresponding to a phase of AC power to which the common mode choke is directly coupled. The secondary turns terminate in series with a burden resistor. Ground faults may be detected by monitoring the voltage across the burden resistor.

Abstract: A double fed induction generator (DFIG) system and controller are presented in which the rotor side converter is preloaded with one or more initial values for resuming regulated operation to counteract transients upon deactivation of the crowbar protection circuit to provide grid fault ride through.

Abstract: A double fed induction generator (DFIG) converter method are presented in which rotor side current spikes are attenuated using series-connected damping resistance in response to grid fault occurrences or grid fault clearances.

Abstract: Embodiments of the present invention provide novel techniques for using a switched converter to provide for three-phase alternating current (AC) rectification, regenerative braking, and direct current (DC) voltage boosting. In particular, one of the three legs of the switched converter is controlled with a set of pulse width modulation (PWM) control signals so that the input AC phase having the highest voltage is rectified and one of the switches in the two other legs is turned on to allow for added voltage. This switching activity allows for voltage from multiple AC line mains to be combined, resulting in an overall boost of the DC voltage of the rectifier. The DC voltage boost can then be applied to the common DC bus in order to ameliorate voltage sags, help with motor starts, and increase the ride-through capability of the motor.

Abstract: A double fed induction generator (DFIG) system and controller are presented in which the rotor side converter is preloaded with one or more initial values for resuming regulated operation to counteract transients upon deactivation of the crowbar protection circuit to provide grid fault ride through.

Abstract: Embodiments of the present invention provide novel techniques for using a switched converter to provide for three-phase alternating current (AC) rectification, regenerative braking, and direct current (DC) voltage boosting. In particular, one of the three legs of the switched converter is controlled with a set of pulse width modulation (PWM) control signals so that the input AC phase having the highest voltage is rectified and one of the switches in the two other legs is turned on to allow for added voltage. This switching activity allows for voltage from multiple AC line mains to be combined, resulting in an overall boost of the DC voltage of the rectifier. The DC voltage boost can then be applied to the common DC bus in order to ameliorate voltage sags, help with motor starts, and increase the ride-through capability of the motor.

Abstract: The present invention relates generally to systems and methods for detecting ground faults (i.e., line-to-ground faults) in motor drive systems. In particular, the embodiments described herein include a common mode choke of a motor drive system having additional (i.e., secondary) turns wound around a core of the common mode choke. These secondary turns are in addition to and separate from a plurality of sets of primary turns wound around the core of the common mode choke, each set of primary turns corresponding to a phase of AC power to which the common mode choke is directly coupled. The secondary turns terminate in series with a burden resistor. Ground faults may be detected by monitoring the voltage across the burden resistor.

Abstract: Embodiments of the present invention provide novel techniques for using a switched converter to provide for three-phase alternating current (AC) rectification, regenerative braking, and direct current (DC) voltage boosting. In particular, one of the three legs of the switched converter is controlled with a set of pulse width modulation (PWM) control signals so that the input AC phase having the highest voltage is rectified and one of the switches in the two other legs is turned on to allow for added voltage. This switching activity allows for voltage from multiple AC line mains to be combined, resulting in an overall boost of the DC voltage of the rectifier. The DC voltage boost can then be applied to the common DC bus in order to ameliorate voltage sags, help with motor starts, and increase the ride-through capability of the motor.

Abstract: Control systems, methods and fully regenerative power conversion systems are presented for mitigating common mode voltages in AC loads by employing inverter and/or active rectifier PWM control using switching sequences with only active vectors where a first vector of each switching sequence differs by one phase switching state from a last vector of a switching sequence of an adjacent sector.

Abstract: Embodiments of the present invention provide novel techniques for using a switched converter to provide for three-phase alternating current (AC) rectification, regenerative braking, and direct current (DC) voltage boosting. In particular, one of the three legs of the switched converter is controlled with a set of pulse width modulation (PWM) control signals so that the input AC phase having the highest voltage is rectified and one of the switches in the two other legs is turned on to allow for added voltage. This switching activity allows for voltage from multiple AC line mains to be combined, resulting in an overall boost of the DC voltage of the rectifier. The DC voltage boost can then be applied to the common DC bus in order to ameliorate voltage sags, help with motor starts, and increase the ride-through capability of the motor.

Abstract: A method and apparatus for identifying a ground fault in a motor drive system that includes at least one three phase power conditioner that is linked to three phase supply lines and to positive and negative DC buses, the method comprising the steps of controlling the power conditioner at an operating frequency to convert power, while controlling the power conditioner to convert power, controlling the power conditioner to apply a common mode signal on each of the three phase supply lines where the common mode signal has a frequency that is different than the operating frequency, sensing the common mode signal on at least one of the three phase supply lines and when the common mode signal on the at least one of the three phase supply lines is greater than a threshold level, indicating that a ground fault has occurred.

Abstract: Control systems, methods and power conversion systems are presented for controlling common mode voltages in AC motor loads driven by inverter PWM control using switching sequences with only active vectors where a first vector of each switching sequence differs by one phase switching state from a last vector of a switching sequence of an adjacent sector, along with enhanced deadtime compensation and reflected wave reduction techniques in providing pulse width modulated switching signals to a switching inverter.

Abstract: Control systems, methods and fully regenerative power conversion systems are presented for mitigating common mode voltages in AC loads by employing inverter and/or active rectifier PWM control using switching sequences with only active vectors where a first vector of each switching sequence differs by one phase switching state from a last vector of a switching sequence of an adjacent sector.

Abstract: Control systems, methods and power conversion systems are presented for controlling common mode voltages in AC motor loads driven by inverter PWM control using switching sequences with only active vectors where a first vector of each switching sequence differs by one phase switching state from a last vector of a switching sequence of an adjacent sector, along with enhanced deadtime compensation and reflected wave reduction techniques in providing pulse width modulated switching signals to a switching inverter.

Abstract: A method and apparatus for identifying a ground fault in a motor drive system that includes at least one three phase power conditioner that is linked to three phase supply lines and to positive and negative DC buses, the method comprising the steps of controlling the power conditioner at an operating frequency to convert power, while controlling the power conditioner to convert power, controlling the power conditioner to apply a common mode signal on each of the three phase supply lines where the common mode signal has a frequency that is different than the operating frequency, sensing the common mode signal on at least one of the three phase supply lines and when the common mode signal on the at least one of the three phase supply lines is greater than a threshold level, indicating that a ground fault has occurred.