A method of iteratively screening a sample of electrolytic capacitors having a predetermined rated voltage is provided. The method can include measuring a first leakage current of a first set of capacitors, calculating a first mean leakage current therefrom, and removing capacitors from the first set having a first leakage current equal to or above a first predetermined value, thereby forming a second set of capacitors. The second set can be subjected to a burn in heat treatment where a test voltage can be applied, then a second leakage current of the second set of capacitors can be measured and a second mean leakage current can be calculated. Capacitors having a second leakage current equal to or above a second predetermined value can be removed from the second set, forming a third set of capacitors. Because of such iterative screening, the capacitors in the third set have low failure rates.

A method of iteratively screening a sample of electrolytic capacitors having a predetermined rated voltage is provided. The method can include measuring a first leakage current of a first set of capacitors, calculating a first mean leakage current therefrom, and removing capacitors from the first set having a first leakage current equal to or above a first predetermined value, thereby forming a second set of capacitors. The second set can be subjected to a burn in heat treatment where a test voltage can be applied, then a second leakage current of the second set of capacitors can be measured and a second mean leakage current can be calculated. Capacitors having a second leakage current equal to or above a second predetermined value can be removed from the second set, forming a third set of capacitors. Because of such iterative screening, the capacitors in the third set have low failure rates.

In an embodiment, an electronic circuit includes: one or more input terminals configured to receive measurement data; and a controller configured to: determine a first harmonic current based on a first current flowing through a first circuit coupled to a line node, where the measurement data includes first current data indicative of the first current, determine a filter harmonic current based on a filter current flowing through an AC filter coupled to the line node, where the measurement data includes filter current data indicative of the filter current, and generate a first flag indicative of failure, degradation or malfunction of a first capacitor or capacitor bank based on the first harmonic current and the filter harmonic current, where the AC filter includes the first capacitor or capacitor bank.

A method and a system for initial self-healing type classification of metallized film capacitors, which relate to the technical field of high-voltage capacitors. The method comprises: applying voltages at different voltage ramp rates to metallized film capacitors to be tested, and determining a voltage bearing range of the metallized film capacitors; determining, according to a corresponding voltage of the metallized film capacitors when initial self-healing occurs and a residual voltage after the initial self-healing occurs, corresponding initial self-healing energy of metallized film capacitors when the initial self-healing occurs; establishing an initial self-healing voltage-energy database according to an initial self-healing voltage of the samples when the initial self-healing occurs and the corresponding initial self-healing energy when the initial self-healing occurs; and classifying the metallized film capacitors by combining an initial self-healing recovery condition and the subsequent service life and performance data of the metallized film capacitors.

A converter device is provided. The converter device includes a filter circuit, a DC link and an active rectifier interconnected between the filter circuit and the DC link. A method for determining at least one parameter (b) of the filter circuit is also provided. The method includes switching the active rectifier into an active state, where a first active rectifier leg connects a first phase of the filter circuit with a positive side of the DC link and a second active rectifier leg connects a second phase of the filter circuit with a negative side of the DC link; determining a time series (y) of current values by measuring a current through the filter circuit; and determining the at least one parameter (b) of the filter circuit by calculating a best fit of the at least one parameter (b) from a difference equation of the filter circuit.

Implementations described herein relate to a capacitor test. In some implementations, a system may include a memory device, one or more capacitors located externally to the memory device, and one or more components configured to initiate a capacitor test for the one or more capacitors. The one or more components may be configured to perform an iteration of the capacitor test for the one or more capacitors, wherein performing the iteration of the capacitor test comprises waiting a time period, increasing a discharge time, reading a counter associated with the capacitor test, and determining whether a value of the counter has increased. The one or more components may be configured to perform another iteration of the capacitor test or terminate the capacitor test based on determining whether the value of the counter has increased.

A capacitance acquiring unit acquires a plurality of initial capacitance values indicating capacitance values of a smoothing capacitor in an initial state and acquires a plurality of operation capacitance values indicating capacitance values of the smoothing capacitor in an operation state, and a deterioration determining unit acquires characteristic information indicating a relationship between AC power and the capacitance value of the smoothing capacitor in the initial state on the basis of a statistic amount of the plurality of initial capacitance values acquired by the capacitance acquiring unit and determines a deterioration state of the smoothing capacitor on the basis of a statistic amount of the plurality of operation capacitance values acquired by the capacitance acquiring unit and the characteristic information.

A method (and corresponding apparatus) of analyzing the behavior of an electrochemical double layer (EDL) by replacing a classic capacitor in an astable multivibrator circuit with an electrochemical cell. By pushing the EDL into resonance, the induced charging and discharging of the double layer results in a square waveform output that has a characteristic frequency audible to the human ear. Variations in the electrolyte concentration and identity yield distinct frequencies. The method provides sensory insight into EDL rearrangement and behavior with an apparatus that is simple and robust. The apparatus allows the analysis of time-dependent EDL rearrangements occurring upon the application of a voltage. The apparatus provides insight, via an audible signal perceptible to the human ear, into the fundamental electrochemical principles governing chemical transformations.