241results about "Rate of change measurement" patented technology

A battery charging circuit comprising: a semiconductor switch having an output connected to a rechargeable battery; a battery charge controller for receiving power from an external source, and supplying output power to a portable device and the input of the semiconductor switch, the current output of the battery charge controller being controllable; and a voltage sensing circuit for: measuring the voltage drop across the battery charge controller; and responding to the voltage drop across the battery charge controller by modulating the semiconductor switch to reduce the quantity of current supplied to the rechargeable battery when the voltage drop is too great; whereby the total power dissipated by the battery charge controller is controlled, the portable device receiving the power it needs to operate and the rechargeable battery receiving any additional available power.

An apparatus is provided to calculate a quantity indicating a charged state of an on-vehicle battery. The battery powers a starter starting up an on-vehicle engine. In the apparatus, a plurality of pairs of data consisting of current and voltage of the battery are acquired at predetermined sampling intervals during a cranking period of the engine in response to starting up the starter. At intervals, a value of an internal resistance of the battery is calculated based on the plurality of pairs of data of current and voltage. The internal resistance is one kind of the charged-state indicating quantity. An open voltage difference is calculated, which is a difference between a pseudo circuit-open voltage of the battery given before starting up the starter and a pseudo circuit-open voltage of the battery given after the cranking period. The value of the internal resistance is corrected using the open voltage difference.

An inspection system (a secondary battery anomaly detection system) has a ROM which stores data including information about a V-dQ/dV curve upon initial charge of a reference secondary battery. At inspection of a secondary battery, upon initial charge from a power supply, an anomaly detecting unit uses an amount of stored electricity calculated from a current value detected by a current detecting unit to calculate a dQ/dV actual measurement value, which is a ratio of a changed amount of the amount of stored electricity to a changed amount of a voltage value detected by a voltage detecting unit, compares the calculated value and the information about the V-dQ/dV curve to determine whether the calculated value corresponds to a feature point on the curve, and detects an anomaly of the secondary battery (incapability of long-term capacity reliability) when the calculated value does not correspond to the feature point on the curve.

A hydraulic fluid change indicating device for an automatic transmission includes a first deterioration rate calculating unit; a deterioration acceleration coefficient calculating unit; and a thermal hydraulic fluid deterioration calculating unit for calculating a thermal hydraulic fluid deterioration according to the first deterioration rate and the deterioration acceleration coefficient. The device further includes a second deterioration rate calculating unit according to an engine speed, input shaft speed, and output shaft speed; a mechanical hydraulic fluid deterioration calculating unit for calculating a mechanical fluid deterioration according to the second deterioration rate; and a determining unit for determining whether or not the thermal hydraulic fluid deterioration or the mechanical hydraulic fluid deterioration is greater than a predetermined hydraulic fluid change threshold.

A secondary-battery monitoring device capable of realizing highly reliable overcurrent detection and a battery pack having it are provided. When an overcurrent flowing to a secondary battery is to be detected by utilizing a current detection voltage generated via on-resistance of a discharge-control switch and a charge-control switch, a voltage correction circuit that generates a correction voltage having a characteristic varied by positive slope or negative slope along with increase in a power supply voltage is provided, and the correction voltage is added to the detection voltage or a reference power supply voltage with the polarity that cancels out the slope of voltage variation caused in the detection voltage, and then the voltage is input to a comparator circuit. In this manner, variation in the overcurrent determination current is reduced.

The invention provides a method for detecting distortion degree of inrush current of a transformer, which adopts abundant high order harmonic resulting in inrush current distortion in inrush current to comprehensively reflect the distortion degree of the inrush current so as to judge whether fault current or magnetizing inrush current leads the current of the transformer to be abnormal according to the distortion degree. Therefore, the distortion degree Q is defined and the calculation method of Q is declared as follows: filtering out direct current components by a difference algorithm; and filtering out fundamental components by a cosine filter. When the judgment result is the fault current, the numerical values of a front sequence and a rear sequence of the cosine filtering are basicallyconsistent, so the Q value is small; when the judgment result is the magnetizing inrush current, the numerical values of the front sequence and the rear sequence of the cosine filtering have big discrepancy, so the Q value is big. The fault current and the magnetizing inrush current can be strictly distinguished by selecting a valve value properly. The method has higher redundancy on the criterion and can use braking with a logic product door, therefore, differential protection can not act in a delaying manner when being dropped into a transformer in fault. The invention has the advantage ofimproving the condition of low long-term correct action rate of the differential protection of the transformer.

A battery internal short-circuit detection apparatus includes: a voltage detection unit for detecting a terminal voltage of the battery; a current detection unit for detecting a discharging current of the battery; a voltage drop and recovery detection unit for detecting a momentary voltage drop of the battery and a recovery from the voltage drop, in response to a result of detection performed by the voltage detection unit; and a determination unit for determining that an internal short circuit has occurred, when a maximum value of the discharging current detected by the current detection unit between the voltage drop and the recovery is equal to or lower than a threshold current.

The invention discloses a high-sensitivity traveling-wave protection method for a high-voltage direct current power transmission line. The method sequentially comprises the steps of powering on a relay protection device; assigning values to traveling-wave protection fixed values Delta initial, Delta u, Delta T, Delta i and Delta du/dt; measuring the voltage u and current i of the line, and calculating a voltage change rate du/dt; judging whether du/dt is greater than Delta initial or not, entering the next step if du/dt is greater than Delta initial, otherwise repeating the step; calculating a voltage change rate calculation value du/dtAVG, an average current change value iAVG and duration T meeting the condition that u is smaller than Delta u; judging whether iAVG at a point is greater than Delta i or not, whether du/dtAVG at the point is greater than Delta du/dt or not and whether T more than or equal to Delta T exists in a time period t1 or not if du/dt is greater than Delta initial, starting protection if the three conditions are met, otherwise continuing judging whether du/dt is greater than Delta initial or not. According to the method, the addition of converter station communication is avoided, and the method is quick in response and high in sensitivity.

A device for switching a semiconductor-based switch includes a terminal that is configured to be connected to a control terminal of the semiconductor-based switch. A controllable activation voltage source is configured to provide a time-varying activation voltage potential. A controllable resistive circuit includes at least two ohmic resistances connected in parallel that are controllable such that at least three resistance values of the parallel connection result. A control device is configured to control the controllable activation voltage source and the controllable resistive circuit independently of one another. The controllable activation voltage source and the controllable resistive circuit are connected to a series connection connected to the terminal. The control device is configured to control the controllable activation voltage source and the controllable resistive circuit in a time-varying manner to obtain time-varying resistance values of the controllable resistive circuit and the time-varying activation voltage potential of the controllable activation voltage source.

Systems and methods for determining the damage level of a battery are provided. An exemplary method includes measuring a terminal voltage of the battery over time while discharging the battery at a predetermined current; calculating a slope of a natural logarithm of a rate of change of a first voltage of the battery over time based on the terminal voltage of the battery; and comparing the calculated slope to a threshold slope that is based on measurements of a plurality of similar batteries with known conditions. The first voltage of the battery may correspond to a voltage across an RC component of an equivalent circuit model for the battery.

The invention relates to a method for detecting anomalies in a battery cell (22), wherein a short-circuit sensor system (20) detects events (44) in a signal of a terminal voltage of the battery cell, which events have successive edges in an interval of time of microseconds, and wherein events detected by the short-circuit sensor system are transmitted to a battery management system (16) which determines anomalies in the battery cells using the detected events. A short-circuit sensor system (20) and a battery system (12) which are set up to carry out the method are also stated.

A signal level crossing detector circuit includes a DC isolator and a detector circuit. The DC isolator has at least a first input, which is operable to receive a high voltage AC signal, and at least a first capacitor, a first plate of the first capacitor being electrically connected to the first input. The detector circuit is operable at a low voltage and has at least a first detector input, the first detector input being electrically connected to a second plate of the first capacitor, the low voltage detector circuit being operable to provide a change in output signal in dependence on a high voltage AC signal on the first input crossing a predetermined signal level. The signal level crossing detector may be single ended or differential.

To provide a technology for obtaining a remaining capacity of a battery with high accuracy. A battery remaining capacity predicting apparatus predicting a remaining capacity of a battery based on an open-circuit voltage of the battery, detects a charge current or a discharge current of the battery, integrates the currents, obtains an estimated value of the open-circuit voltage that corresponds to an integrated value of the currents on the basis of conversion information representing a capacity necessary for the open-circuit voltage of the battery to change by a predetermined capacity, obtains a measured value of the open-circuit voltage on the basis of the detected current and information on internal impedance, and obtains the remaining capacity of the battery based on the estimated value of the open-circuit voltage by correcting the information on the internal impedance so that the measured value of the open-circuit voltage is equalized to the estimated value of the open-circuit voltage, or by correcting the conversion information so that the estimated value of the open-circuit voltage is equalized to the measured value of the open-circuit voltage.

If a particular selection condition is satisfied, a non-load voltage calculation unit (105) calculates a no-load voltage Vsep as a voltage piece when the current in approximate straight line obtained by statistical processing using the method of least squares for a plurality of sets of data containing current data I(n) and voltage data V(n) is zero. If a particular current condition or voltage condition is continuously satisfied for a predetermined time, an open-circuit voltage calculation unit (106) calculates a secondary cell terminal voltage as an open-circuit voltage Voc and a voltage-at-zero-current storing unit (108) stores voltage-at-zero-current Vzo calculated by a voltage-at-zero-current calculation unit (107). By using a predetermined voltage change amount adjustment constant ΔVbc/adjustment coefficient Kb, an electromotive force change constant Keq, and a polarization voltage generation constant Kpol, an estimated charge/discharge electric amount calculation unit (118A) calculates an estimated charge/discharge electricity amount ΔQe as a function of the change amount ΔVzo of a voltage-at-zero-current Vzo. It is possible to estimate charge/discharge electricity amount without being affected by the current measurement error.

The invention provides a method and equipment for detecting a single-phase earth fault of a transmission and distribution line. The method comprises the following steps of: 1, detecting the mutation rate of transient current of the line, wherein the mutation rate Delta Ip/Delta t of the transient current is greater than Rh when the transient current positively jumps; and 2, determining a short-circuit earth fault when detecting that line voltage drops and V is smaller than Vh, wherein the sequence of the step 1 and the step 2 can be changed. According to the fault detection equipment, false alarm or alarm omission can be prevented, demands of different users can be met, and the equipment is applicable for mass production.

Disclosed is a method and apparatus for charging electrically powered devices. In accordance with the invention, the device is powered by two storage or charge receiving devices. One of these devices is capable of receiving a substantial charge very rapidly while the other device requires a longer time to receive a charge. The advantage is that the powered device can be used almost instantly and continually while at the same time rebuilding electrical charge. The present invention further relates to a system for protecting the charging device from being damaged from an electrical surge, such as from a lightening strike.