The converter device includes a rectification circuit that receives, as an input, AC power from an AC power supply, and performs full-wave rectification on the AC power received, a booster circuit that boosts an output voltage from the rectification circuit, a smoothing capacitor that smooths an output voltage from the booster circuit, and outputs a voltage smoothed, to the load, and a controller that controls the booster circuit. The booster circuit includes a plurality of booster sections each of which includes a reactor, a switching element, and a reverse-blocking diode. The controller maintains, in an ON state, the switching element included in at least one of the plurality of booster sections for a predetermined time period to determine the presence or absence of a fault of the booster section.

A method for detecting an open-phase condition of a transformer having a grounded-wye high voltage side connection including monitoring current flowing in a neutral connection on the high voltage side of the transformer in real time by voltage relaying and current relaying to identify an open phase condition signature in a signal capable of characterizing change of current magnitude. A current signal may be injected onto the neutral terminal and the zero-sequence mode of the transformer monitored to detect an open-phase condition indicated by an increase in network impedance and decrease or elimination of the injection current.

Provided is a diagnostic device for a coil including a voltage application unit applying an impulse voltage to the coil; a response voltage detection unit detecting a response voltage from the coil with respect to the impulse voltage; an index calculation unit calculating a determination index indicating an electrical feature of the coil based on the response voltage; and a determination unit determining whether there is an abnormality in a target coil to be diagnosed by comparing the determination index of a reference coil that is the coil that is normal and the determination index of the target coil. At least one of a zero cross point at which the response voltage intersects with a reference voltage and a peak voltage on a positive side and a negative side of the response voltage is used as the determination index, in addition to a circuit constant of the coil.

Provided is a diagnostic device for a coil including a voltage application unit applying an impulse voltage to the coil; a response voltage detection unit detecting a response voltage from the coil with respect to the impulse voltage; an index calculation unit calculating a determination index indicating an electrical feature of the coil based on the response voltage; and a determination unit determining whether there is an abnormality in a target coil to be diagnosed by comparing the determination index of a reference coil that is the coil that is normal and the determination index of the target coil. At least one of a zero cross point at which the response voltage intersects with a reference voltage and a peak voltage on a positive side and a negative side of the response voltage is used as the determination index, in addition to a circuit constant of the coil.

The disclosure relates to a fault detection method for a Buck converter based on an inverse Kalman filter, which belongs to the field of fault detection for power converters. The method includes: establishing a hybrid discrete model of a non-ideal Buck converter in Continuous Conduction Mode (CCM); acquiring a state equation and an observation equation of the Buck converter; acquiring the input voltage, the switching state, the inductive current and the output voltage in a working state, and determining the state matrix of the Buck converter; estimating a parameter matrix at time k according to the state matrix, the state equation and the observation equation; determining an estimated value of each component according to the estimated parameter matrix of the Buck converter at time k; and determining whether the Buck converter is faulty or not according to the estimated value of each component. The problems of poor real-time performance and low accuracy of fault diagnosis for the Buck converter at present are solved, and the real-time performance and accuracy of fault detection for the Buck converter are improved.

The disclosure relates to a fault detection method for a Buck converter based on an inverse Kalman filter, which belongs to the field of fault detection for power converters. The method includes: establishing a hybrid discrete model of a non-ideal Buck converter in Continuous Conduction Mode (CCM); acquiring a state equation and an observation equation of the Buck converter; acquiring the input voltage, the switching state, the inductive current and the output voltage in a working state, and determining the state matrix of the Buck converter; estimating a parameter matrix at time k according to the state matrix, the state equation and the observation equation; determining an estimated value of each component according to the estimated parameter matrix of the Buck converter at time k; and determining whether the Buck converter is faulty or not according to the estimated value of each component. The problems of poor real-time performance and low accuracy of fault diagnosis for the Buck converter at present are solved, and the real-time performance and accuracy of fault detection for the Buck converter are improved.

A test device according to an embodiment of the present invention includes: a first measurement terminal connected to one end of a first coil to be tested; a second measurement terminal connected to another end of the first coil; a direct-current power source connected to the first measurement terminal; a first semiconductor switch connected between the second measurement terminal and a ground; and a drive unit for turning on and off the first semiconductor switch.

The present invention relates to a device for evaluating the performance of a superconductive coil for a high-temperature superconductive rotary machine and a method for evaluating the performance of a superconductive coil thereby. The technical gist of the present invention is to provide schemes for evaluating the stability of a superconductive coil and verifying the reliability thereof, to evaluate/confirm whether or not the same can be commercialized, and to evaluate/confirm the threshold current of a superconductive wire for manufacturing a superconductive coil or the upper limit of the operating current thereof, and is characterized in that the electromagnetic, thermal, and mechanical performances of a superconductive coil for a second-generation high-temperature superconductive rotary machine can be evaluated. The present invention, configured as above, is characterized in that refrigerant supply setup can be freely varied during cooling of a bobbin for cooling a superconductive coil, the magnitude of the electric current through an outer stator can be easily changed according setup control, thereby making it possible to differently adjust the magnitude of a time-variant magnetic field applied to the superconductive coil, and it accordingly becomes possible to set and control an evaluation environment identical to the actual use environment in which the superconductive coil is to be used, thereby securing the reliability of evaluation of performance of the superconductive coil.

The present disclosure relates to a system for monitoring a solenoid operated valve including at least one coil and at least one spool. The system compares a normalized current signature and a normalized current signature comparator to determine a spool fault condition

A system and method for detecting the location of coil open and coil short faults. The method includes obtaining an instantaneous admittance signature of each solenoid coil, sending out a periodic test signal to each valve, obtaining a new admittance signature; and calculating the coil-open and coil-short faults.