Method and system for detecting a failed current sensor in a three-phase machine

• Main Authors: GERDES JESSE R, HARTMAN MARK E, WAI JACKSON, SPECKHART GREGORY J
• Format: Patent
• Language: English
• Published: 23.08.2011
• Subjects: CONTROL OR REGULATING SYSTEMS IN GENERAL; CONTROLLING; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; GENERATION; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS ORELEMENTS; PHYSICS; REGULATING

A method of detecting one or more failed current sensor and estimating a phase current for the failed current sensor on a three-phase machine is disclosed. The method may include detecting one or more failed current sensor by determining if an absolute value of a sum of the phase currents of the motor is below an open circuit value. The method may also include determining which phase currents are approximately zero, for each phase current associated with each phase of the motor, if the sum of the phase currents of the motor is not below the open circuit value. The method may further include estimating the phase current for the failed current sensor by determining the phase current value for the failed current sensor, that when added to the phase currents of the remaining current sensors, will make the sum of all the phase currents equal to approximately zero.