Abstract: Systems and methods for reducing current imbalance in a motor, where one embodiment comprises a system having an ESP installed in a well, an electric drive, and a power cable coupled between the drive and the ESP's motor. The electric drive generates output voltage waveforms (e.g., PWM waveforms) for multiple phases that may have different impedances. The system monitors the current of each phase at the output of the electric drive and determines a current imbalance between the phases. The drive generates voltage adjustments (e.g., duty cycle adjustments) corresponding to the respective phases, and applies each voltage adjustment to the corresponding voltage waveform. For example, the drive may determine an average of the phase currents, determine the difference between each phase current and the average, and multiply the result by a gain factor to generate the voltage for each phase. The process is iteratively performed to reduce the current imbalance.

Abstract: Systems and methods for reducing current imbalance in a motor, where one embodiment comprises a system having an ESP installed in a well, an electric drive, and a power cable coupled between the drive and the ESP's motor. The electric drive generates output voltage waveforms (e.g., PWM waveforms) for multiple phases that may have different impedances. The system monitors the current of each phase at the output of the electric drive and determines a current imbalance between the phases. The drive generates voltage adjustments (e.g., duty cycle adjustments) corresponding to the respective phases, and applies each voltage adjustment to the corresponding voltage waveform. For example, the drive may determine an average of the phase currents, determine the difference between each phase current and the average, and multiply the result by a gain factor to generate the voltage for each phase. The process is iteratively performed to reduce the current imbalance.

Abstract: Systems and methods for providing notifications to monitoring systems that are remotely located from a well upon failure of a surge suppressor in a drive system for equipment used in the operation of the well. In one embodiment, an ESP system is installed in a well. A VSD having a surge suppressor is coupled between a power source and the ESP system. The surge suppressor is monitored to detect a failure of its surge suppression capabilities. In response to detecting a failure, a notification is provided to a monitoring system that is located remotely from the well. The notifications may be provided via phone call, email, text message or other means. The surge suppressor may also provide a local indication of the failure. The VSD may be configured to continue operation despite the failure of the surge suppression capability.

Abstract: Systems and methods for providing notifications to monitoring systems that are remotely located from a well upon failure of a surge suppressor in a drive system for equipment used in the operation of the well. In one embodiment, an ESP system is installed in a well. A VSD having a surge suppressor is coupled between a power source and the ESP system. The surge suppressor is monitored to detect a failure of its surge suppression capabilities. In response to detecting a failure, a notification is provided to a monitoring system that is located remotely from the well. The notifications may be provided via phone call, email, text message or other means. The surge suppressor may also provide a local indication of the failure. The VSD may be configured to continue operation despite the failure of the surge suppression capability.

Abstract: Systems and methods for reducing harmonic distortion in a power system resulting from non-linear loading on the power system. The power at an interface with a power source is measured, and then distortion in the waveforms of the supplied power is identified. Cancellation signals which cancel all or part of the distortion are then generated and injected at the interface. In one embodiment, the power is sampled to determine the waveform, and then a Fast Fourier Transform is performed on the waveform to convert it to the frequency domain. Harmonics of the fundamental frequency can then be identified, and conjugates of the harmonics generated. An inverse Fast Fourier Transform is performed on the conjugates to generate a signal which is amplified to produce the cancellation signal.

Abstract: Systems and methods for reducing harmonic distortion in a power system resulting from non-linear loading on the power system. The power at an interface with a power source is measured, and then distortion in the waveforms of the supplied power is identified. Cancellation signals which cancel all or part of the distortion are then generated and injected at the interface. In one embodiment, the power is sampled to determine the waveform, and then a Fast Fourier Transform is performed on the waveform to convert it to the frequency domain. Harmonics of the fundamental frequency can then be identified, and conjugates of the harmonics generated. An inverse Fast Fourier Transform is performed on the conjugates to generate a signal which is amplified to produce the cancellation signal.