Abstract: Systems and methods in accordance with this invention provide a power converter including an input signal terminal, a first output signal at a first output signal terminal, and a controller. The controller is adapted to switch the first output signal from a first value to a second value, measure a voltage at the input signal terminal as a function of time, set a flag to a first flag value if the measured voltage falls below a predetermined value within a first predetermined time interval after the first output signal has been switched from the first value to the second value, otherwise set the flag to a second flag value, and save the flag in a memory. Numerous other aspects are also provided.

Abstract: Systems and methods in accordance with this invention provide a power converter including an input signal terminal, a first output signal at a first output signal terminal, and a controller. The controller is adapted to switch the first output signal from a first value to a second value, measure a voltage at the input signal terminal as a function of time, set a flag to a first flag value if the measured voltage falls below a predetermined value within a first predetermined time interval after the first output signal has been switched from the first value to the second value, otherwise set the flag to a second flag value, and save the flag in a memory. Numerous other aspects are also provided.

Abstract: A method for controlling at least two variable frequency drives connected in parallel. The method comprises, for each variable frequency drive, communicating a magnetizing current component value to a master controller, and receiving a speed demand, a flux demand, and an average magnetizing current component value from the master controller. The method also comprises determining a motor speed and a motor flux based on measurements of a stator voltage and current of a motor coupled to the variable frequency drive, determining a speed reference based on a torque current component value, and determining a flux reference based on the magnetizing current component value and the average magnetizing current component value. The method further comprises adjusting a torque current component based on the speed reference and/or adjusting a magnetizing current component based on the flux reference.