Abstract: Power conversion systems, disclosed examples include power conversion systems, ground fault detection apparatus and methods to detect and identify ground faults in a power conversion system using AC coupling to sense a system voltage to determine a leakage flux linkage, and to identify a faulted converter phase based on a phase shift angle of the leakage flux linkage.

Abstract: Power conversion systems, disclosed examples include power conversion systems, ground fault detection apparatus and methods to detect and identify ground faults in a power conversion system using AC coupling to sense a system voltage to determine a leakage flux linkage, and to identify a faulted converter phase based on a phase shift angle of the leakage flux linkage.

Abstract: Methods an apparatus are presented for identifying ground fault locations in multi-drive systems in which individual drives perform self-diagnosis for detected faults based on an identified fault signal frequency while the system drives continue operation, and a ground fault location system identifies suspected drives and individually confirms or exonerates individual drives by selective command speed adjustment while the drives remain operational within system tolerance ranges.

Abstract: Precharging systems and methods are presented for precharging a DC bus circuit in a power conversion system, in which precharging current is connected through a precharging resistance coupled between only a single AC input line and the DC bus circuit when the DC bus voltage is less than a non-zero threshold, and a controller individually activates controllable rectifier switching devices when the DC bus voltages greater than or equal to the threshold using DC gating or pulse width modulation to selectively provide a bypass path around the precharging resistance for normal load currents in the power conversion system.

Abstract: A HRG ground fault detector and method for detecting a ground fault in a High Resistance Ground (HRG) system are provided. The HRG ground fault detector in one example embodiment includes a first input A coupled to a first phase PHA of the HRG system, a second input B coupled to a second phase PHB, and a third input C coupled to a third phase PHC, with the HRG ground fault detector generating a simulated neutral voltage VN? from the first phase PHA, the second phase PHB, and the third phase PHC. The simulated neutral voltage VN? has a zero voltage potential when the first phase PHA, the second phase PHB, and the third phase PHC are equal. The HRG ground fault detector further compares the simulated neutral voltage VN? to a predetermined fault voltage threshold, and detects a HRG ground fault if the simulated neutral voltage VN? exceeds the threshold.

Abstract: Methods, apparatus and computer readable mediums are presented for controlling a multiphase inverter in which third harmonic injection pulse width modulation (THIPWM) is used for generating inverter switching control signals at or above a non-zero threshold inverter output frequency, and high frequency injection discontinuous pulse width modulation (HFIDPWM) is used for inverter output frequencies below the threshold, where the threshold frequency corresponds to a threshold period less than or equal to the thermal impedance time constant of the inverter switching devices, and the injected high frequency component for HFIDPWM corresponds to a common mode period less than the thermal impedance time constant to mitigate thermal stress on the inverter switches and low speed inverter output derating.

Abstract: Methods, apparatus and computer readable mediums are presented for controlling a multiphase inverter in which third harmonic injection pulse width modulation (THIPWM) is used for generating inverter switching control signals at or above a non-zero threshold inverter output frequency, and high frequency injection discontinuous pulse width modulation (HFIDPWM) is used for inverter output frequencies below the threshold, where the threshold frequency corresponds to a threshold period less than or equal to the thermal impedance time constant of the inverter switching devices, and the injected high frequency component for HFIDPWM corresponds to a common mode period less than the thermal impedance time constant to mitigate thermal stress on the inverter switches and low speed inverter output derating.

Abstract: Methods an apparatus are presented for identifying ground fault locations in multi-drive systems in which individual drives perform self-diagnosis for detected faults based on an identified fault signal frequency while the system drives continue operation, and a ground fault location system identifies suspected drives and individually confirms or exonerates individual drives by selective command speed adjustment while the drives remain operational within system tolerance ranges.

Abstract: A PLC or other industrial controller programmed to locate ground faults in a networked high resistance grounded multi-drive system through network communications messaging to automatically place networked motor drives in various operational states to isolate individual drives for ground fault identification testing and selectively identify individual drives as suspected ground fault locations.

Abstract: A HRG ground fault detector and method for detecting a ground fault in a High Resistance Ground (HRG) system are provided. The HRG ground fault detector in one example embodiment includes a first input A coupled to a first phase PHA of the HRG system, a second input B coupled to a second phase PHB, and a third input C coupled to a third phase PHC, with the HRG ground fault detector generating a simulated neutral voltage VN? from the first phase PHA, the second phase PHB, and the third phase PHC, wherein the simulated neutral voltage VN? comprises a zero voltage potential when the first phase PHA, the second phase PHB, and the third phase PHC are equal, comparing the simulated neutral voltage VN? to a predetermined fault voltage threshold, and detecting a HRG ground fault if the simulated neutral voltage VN? exceeds the threshold.