Abstract: A cable condition monitoring sensor device includes a TMR magnetic field sensor module, a high-pass filtering module, and a signal-amplifying module which are sequentially connected. The TMR magnetic field sensor module measures a magnetic field change signal of a cable, converts the same into a voltage signal, and outputs the voltage signal to the high-pass filtering module. The high-pass filtering module filters out DC bias of the voltage signal, and transmits the filtered voltage signal to the signal-amplifying module. The signal-amplifying module amplifies the filtered voltage signal to obtain an output voltage signal and outputs the output voltage signal. In the present invention, a common mode current to be measured in the cable is extracted by placing the magnetic shielding ring made of ferromagnetic material outside the cable to filter out a differential mode load current in the cable, and the magnitude of the common mode current is determined.

Abstract: The invention relates to a method, a device and a system for monitoring the IGBT junction temperature, wherein the linear relationship between each turn-off DC bus ringing peak voltage and the corresponding turn-off IGBT junction temperature, the phase current directions, and the initial and secondary states of the half-bridge arms are used to accurately determine the monitoring time of the turn-off DC bus ringing peak voltage, thereby obtaining the IGBT junction temperature at a converter level with higher sensitivity. The IGBT junction temperature obtained using the junction temperature monitoring method provided by the invention is an appropriate converter-level parameter, which has a good application prospect in multi-IGBT junction temperature estimation.

Abstract: Disclosed are an IGBT-module condition monitoring equipment and method. The IGBT-module condition monitoring equipment includes an IGBT module, a gate turning-on voltage overshoot monitoring module, a driving circuit, a bond wire state judging module, and a signal acquisition module. The breakage condition of bond wires is obtained by comparing a monitored actual gate turning-on voltage overshoot with a preset reference gate turning-on voltage overshoot threshold. The present invention solves the problem encountered in monitoring the aging of IGBT bond wires in power electronic converters.

Abstract: Disclosed is a ground-wall insulation aging monitoring and locating method for a converter transformer. A neutral lead of three-phase windings on a valve side of a converter transformer is adjusted, an insulation leakage current of a certain phase winding on the valve side before aging is measured, a common-mode component and a differential-mode component in the insulation leakage current before aging are extracted, and a common-mode equivalent capacitance and a differential-mode equivalent capacitance before aging are calculated; a common-mode equivalent capacitance and a differential-mode equivalent capacitance after aging are calculated in the same way.

Abstract: A method and device for online insulation monitoring of a motor are applied to an inverter-driven motor system. The method includes: measuring phase-to-ground voltages of three-phase inlet lead ends of a motor; acquiring leakage currents of the three-phase inlet lead ends of the motor; acquiring a voltage common-mode component, a voltage differential-mode component, a current common-mode component and a current differential-mode component from the phase-to-ground voltages and the leakage currents; and acquiring ground-wall insulation equivalent capacitance and phase-to-phase insulation equivalent capacitance according to the components. A ground-wall insulation monitoring result and a phase-to-phase insulation monitoring result are distinguished from each other by the acquired ground-wall insulation equivalent capacitance and phase-to-phase insulation equivalent capacitance, such that two kinds of insulation are monitored respectively.

Abstract: Disclosed are an IGBT-module condition monitoring equipment and method. The IGBT-module condition monitoring equipment includes an IGBT module, a gate turning-on voltage overshoot monitoring module, a driving circuit, a bond wire state judging module, and a signal acquisition module. The breakage condition of bond wires is obtained by comparing a monitored actual gate turning-on voltage overshoot with a preset reference gate turning-on voltage overshoot threshold. The present invention solves the problem encountered in monitoring the aging of IGBT bond wires in power electronic converters.

Abstract: A method and device for online insulation monitoring of a motor are applied to an inverter-driven motor system. The method includes: measuring phase-to-ground voltages of three-phase inlet lead ends of a motor; acquiring leakage currents of the three-phase inlet lead ends of the motor; acquiring a voltage common-mode component, a voltage differential-mode component, a current common-mode component and a current differential-mode component from the phase-to-ground voltages and the leakage currents; and acquiring ground-wall insulation equivalent capacitance and phase-to-phase insulation equivalent capacitance according to the components. A ground-wall insulation monitoring result and a phase-to-phase insulation monitoring result are distinguished from each other by the acquired ground-wall insulation equivalent capacitance and phase-to-phase insulation equivalent capacitance, such that two kinds of insulation are monitored respectively.

Abstract: A cable condition monitoring sensor device includes a TMR magnetic field sensor module, a high-pass filtering module, and a signal-amplifying module which are sequentially connected. The TMR magnetic field sensor module measures a magnetic field change signal of a cable, converts the same into a voltage signal, and outputs the voltage signal to the high-pass filtering module. The high-pass filtering module filters out DC bias of the voltage signal, and transmits the filtered voltage signal to the signal-amplifying module. The signal-amplifying module amplifies the filtered voltage signal to obtain an output voltage signal and outputs the output voltage signal. In the present invention, a common mode current to be measured in the cable is extracted by placing the magnetic shielding ring made of ferromagnetic material outside the cable to filter out a differential mode load current in the cable, and the magnitude of the common mode current is determined.

Abstract: Disclosed is a ground-wall insulation aging monitoring and locating method for a converter transformer. A neutral lead of three-phase windings on a valve side of a converter transformer is adjusted, an insulation leakage current of a certain phase winding on the valve side before aging is measured, a common-mode component and a differential-mode component in the insulation leakage current before aging are extracted, and a common-mode equivalent capacitance and a differential-mode equivalent capacitance before aging are calculated; a common-mode equivalent capacitance and a differential-mode equivalent capacitance after aging are calculated in the same way.

Abstract: A fault detection system for a wind turbine includes a doubly-fed induction generator (DFIG). The DFIG includes a wye-ring configured for at least three electrical phases. The fault detection system includes a data acquisition system including at least three sensors. Each sensor of said at least three sensors is configured to electrically couple with and measure a respective voltage of each phase of the at least three electrical phases of the wye-ring. The fault detection system further includes an alert system coupled to said data acquisition system. The alert system is configured to apply a Fourier transform to the respective measured voltages of each phase of the at least three electrical phases of the wye-ring. The alert system is further configured to provide an indication of a condition of the wye-ring based upon the transformed measured voltages.

Abstract: A fault detection system for a wind turbine includes a doubly-fed induction generator (DFIG). The DFIG includes a wye-ring configured for at least three electrical phases. The fault detection system includes a data acquisition system including at least three sensors. Each sensor of said at least three sensors is configured to electrically couple with and measure a respective voltage of each phase of the at least three electrical phases of the wye-ring. The fault detection system further includes an alert system coupled to said data acquisition system. The alert system is configured to apply a Fourier transform to the respective measured voltages of each phase of the at least three electrical phases of the wye-ring. The alert system is further configured to provide an indication of a condition of the wye-ring based upon the transformed measured voltages.

Abstract: A method implemented using a processor based device includes obtaining a measured electrical signal from an electrical device coupled to a mechanical device and generating a signal signature representative of a fault in the mechanical device based on the measured electrical signal. The method also includes determining a diagnostic parameter based on a harmonic frequency of the signal signature and determining the fault in the mechanical device based on the diagnostic parameter.

Abstract: A method implemented using a controller based device includes receiving a measured electrical signal from an electrical device of an electromechanical device and receiving a measured vibration signal from a mechanical device of the electromechanical device, coupled to the electrical device. The method further includes determining a first signal signature based on the measured electrical signal and determining a second signal signature based on the measured vibration signal. The method also includes determining a diagnostic parameter based on the first signal signature and the second signal signature and determining a fault in the mechanical device based on the diagnostic parameter.

Abstract: A method for estimating a speed of an induction motor includes applying a voltage to the induction motor and measuring a current of the induction motor. A current fast fourier transform (FFT) of the current is then determined and a slip of the induction motor is calculated based on the current FFT. A speed of the induction motor is then estimated based on the slip of the induction motor.

Abstract: Systems and methods are disclosed for on-line monitoring of the condition of the stator insulation of an AC motor or an electric generator. In certain embodiments, the system includes a transformer surrounding each pair of input and output cables associated with a given phase of power provided to the AC motor or generated by the electric generator. In another embodiment, a transformer surrounds the three input cables (for an AC motor) or the three output cables (for an electric generator) that correspond to phases of the AC motor or electric generator. In both embodiments, the transformers generate voltages that may be used to monitor leakage currents associated with the cables. A microcontroller monitors the voltages generated by the transformers and determines the condition of the stator insulation of the AC motor or the electric generator based on the voltages.

Abstract: A method for estimating a speed of an induction motor includes applying a voltage to the induction motor and measuring a current of the induction motor. A current fast fourier transform (FFT) of the current is then determined and a slip of the induction motor is calculated based on the current FFT. A speed of the induction motor is then estimated based on the slip of the induction motor.

Abstract: A system configured to monitor an operating electrical device includes a testing channel coupled to the device. The device is coupled to an electric power source through at least one electric power transmission channel. The power source is configured to transmit electric power at a first frequency. The testing channel is coupled to the power transmission channel. The system also includes a signal generator coupled to the testing channel. The signal generator is configured to inject testing signals into the testing channel at a second frequency that is greater than the first frequency. The system further includes at least one apparatus magnetically coupled to the power transmission channel. The magnetically coupled apparatus is configured to present a first impedance to the electric power at the first frequency and present a second impedance to the test signals at the second frequency. The second impedance is greater than the first impedance.

Abstract: A method of detecting faults in a wind turbine generator based on current signature analysis is disclosed herein. The method includes acquiring a set of electrical signals representative of an operating condition of a generator. Further, the electrical signals are processed to generate a normalized spectrum of electrical signals. A fault related to a gearbox or bearing or any other component associated with the generator is detected based on analyzing the current spectrum.

Abstract: A method for detection of rotor bar faults in an electric machine is provided. The method includes acquiring electrical signals from the electric machine that are representative of the operative condition of the machine. The symmetrical components from the electrical signals are eliminated by squaring an instantaneous value of each data point from the electrical signals and summing the squared values. The method further includes the step of eliminating discontinuities in the electrical signals by applying a window function to compute weighted representation of the squared values. Furthermore, the method includes the step of normalizing the weighted representation to obtain spectral information. The faults in the rotor bar are detected by analyzing the spectral information obtained after normalization.

Abstract: A method implemented using a controller based device includes receiving a measured electrical signal from an electrical device of an electromechanical device and receiving a measured vibration signal from a mechanical device of the electromechanical device, coupled to the electrical device. The method further includes determining a first signal signature based on the measured electrical signal and determining a second signal signature based on the measured vibration signal. The method also includes determining a diagnostic parameter based on the first signal signature and the second signal signature and determining a fault in the mechanical device based on the diagnostic parameter.