Rockwell Automation Technologies Incorporated

Jeffrey D McGuire

Lixiang Wei

Jiangang Hu

Zhijun Liu

Russel J Kerkman

Timothy M Rowan

Nickolay N Guskov

Carlos Rodríguez Valdez

David Dahl

A method and controller to automatically determine a grounding condition of a motor drive, in which an inverter is operated at a predetermined frequency while a load resistor is connected between a single phase of a motor drive inverter output and a reference node, a leakage flux linkage value is computed according to a neutral-ground voltage of the motor drive, and a processor determines whether the motor drive is solid grounded, high-resistance grounded, or floating according to the leakage flux linkage value. In certain examples, the processor automatically turns the inverter off while the load resistor is connected between the single phase of the inverter output and the reference node, and automatically determines whether the motor drive is delta corner grounded according to the neutral-ground voltage.

Automatic system grounding condition detection

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.

System and method for ground fault detection

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.

Apparatus and method for automatic ground fault location determination in high resistance grounded motor drive system

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.

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 PHof the HRG system, a second input B coupled to a second phase PH, and a third input C coupled to a third phase PH, with the HRG ground fault detector generating a simulated neutral voltage Vfrom the first phase PH, the second phase PH, and the third phase PH. The simulated neutral voltage Vhas a zero voltage potential when the first phase PH, the second phase PH, and the third phase PHare equal. The HRG ground fault detector further compares the simulated neutral voltage Vto a predetermined fault voltage threshold, and detects a HRG ground fault if the simulated neutral voltage Vexceeds the threshold.

HRG ground fault detector and method using phase inputs to generate a simulated neutral voltage

Methods, control apparatus and computer readable mediums are presented for controlling a switching inverter in which a controller selectively suspends PWM carrier signals to provide inverter switching control signals using zero vectors in response to a maximal pulse width value for a present PWM half cycle being greater than a threshold value, and accumulates a present output control value for individual output phases for use in a subsequent PWM half cycle for selective effective reduction in switching frequency for low-speed operation while maintaining high frequency control loop sampling.

Adjustable PWM method to increase low speed starting torque and inverter voltage measurement accuracy

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.

Methods and power conversion system control apparatus to control IGBT junction temperature at low speed

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.

Growing community of inventors

Franklin, WI, United States of America

Jeffrey D McGuire