CN112557779A - Converter abnormity monitoring method and device - Google Patents
Converter abnormity monitoring method and device Download PDFInfo
- Publication number
- CN112557779A CN112557779A CN201910915591.8A CN201910915591A CN112557779A CN 112557779 A CN112557779 A CN 112557779A CN 201910915591 A CN201910915591 A CN 201910915591A CN 112557779 A CN112557779 A CN 112557779A
- Authority
- CN
- China
- Prior art keywords
- value
- reactor
- charging
- actual
- inductance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/005—Testing of electric installations on transport means
- G01R31/008—Testing of electric installations on transport means on air- or spacecraft, railway rolling stock or sea-going vessels
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2611—Measuring inductance
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention provides an abnormity monitoring method and device of a converter, which are used for monitoring a pre-charging resistor and a reactor which are positioned in a middle loop of the converter. The abnormality monitoring method includes: acquiring a power grid side voltage value, a middle loop voltage value and a middle loop current value in a pre-charging process; estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on the least square principle according to the acquired voltage value of the power grid side, the voltage value of the middle loop and the current value of the middle loop; and respectively comparing the actual value and the design value of the pre-charging resistor and the actual value and the design value of the inductor to judge whether the pre-charging resistor and the reactor are abnormal. The invention also provides an abnormality monitoring device for realizing the abnormality monitoring method. According to the abnormity monitoring method and the abnormity monitoring device provided by the invention, an alarm can be effectively sent out in time when the resistance value of the pre-charging resistor and the inductance value of the reactor are abnormal, so that the reliability of the converter is improved.
Description
Technical Field
The invention relates to the field of control of electrical equipment, in particular to an abnormality monitoring method and device for a current transformer.
Background
The converter, also known as rectifier, net side converter, its one end links to each other with alternating current or direct current electric wire netting, and the other end links to each other with direct current return circuit, can realize the two-way flow of energy, all has very extensive application in fields such as some high-power traction transmission, direct current transmission, new forms of energy. Particularly for the electrified urban rail transit, the high-power traction converter is used as the heart of a high-power train of the core equipment of the electrified urban rail transit, and the performance of the high-power traction converter directly influences the running performance of the train.
At present, a common traction converter comprises an intermediate loop connected with a network side, the intermediate loop transfers electric energy of the network side to an inversion module of the traction converter after a pre-charging process, and the inversion module converts the electric energy of the network side and outputs the electric energy to a load at the rear end. The intermediate circuit mainly comprises a pre-charging resistor and a reactor, and the pre-charging process of the intermediate circuit can effectively prevent the unstable output condition of the subsequent inverter module caused by the unstable voltage and current on the side of the power grid, so that the pre-charging resistor and the reactor of the intermediate circuit are required to have good performance, and the stable operation of the train traction transmission system can be ensured.
At present, in the urban rail vehicle repair process, the working states of the pre-charging resistor and the reactor cannot be monitored in the running process of a train, the states of the pre-charging resistor and the reactor are monitored mainly in a regular inspection mode, namely, a special measuring device is regularly adopted to detect the resistance value of the pre-charging resistor and the inductance value of the reactor, the deviation between a detection value and a design value is compared, and if the deviation is overlarge, the pre-charging resistor or the reactor is considered to be abnormal and needs to be replaced. The periodic detection method has the following two disadvantages:
(1) when the pre-charging resistor and the reactor are abnormal, the alarm cannot be given in time and the abnormal pre-charging resistor or reactor cannot be processed in time, so that the influence on the train operation caused by further deterioration of the abnormality is avoided;
(2) when the pre-charging resistor and the reactor are regularly detected, the charging point resistor and the reactor are still in a normal state, and the condition belongs to excessive maintenance and causes resource waste.
Therefore, there is a need for an abnormality monitoring method and apparatus for a converter, which can monitor the operating states of a pre-charging resistor and a reactor during the operation of a train, and can issue an alarm in time when the resistance value of the pre-charging resistor and the inductance value of the reactor are abnormal, so as to avoid further deterioration of the abnormality and influence on the reliable operation of the train.
Disclosure of Invention
The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
In order to solve the above problems, the present invention provides an abnormality monitoring method for a converter, which is used for monitoring a pre-charge resistor and a reactor in an intermediate circuit of the converter, wherein the intermediate circuit transfers electric energy on a grid side to an inverter module of the converter after a pre-charge process, and the abnormality monitoring method specifically includes:
acquiring a power grid side voltage value, a middle loop voltage value and a middle loop current value in a pre-charging process;
estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on the least square principle according to the acquired voltage value of the power grid side, the voltage value of the middle loop and the current value of the middle loop; and
and comparing the actual resistance value and the designed resistance value of the pre-charging resistor and the actual inductance value and the designed inductance value of the inductor respectively to judge whether the pre-charging resistor and the reactor are abnormal or not.
In an embodiment of the foregoing anomaly monitoring method, optionally, the acquiring a grid-side voltage, an intermediate circuit voltage, and an intermediate circuit current during the pre-charging process further includes: sampling for multiple times in the pre-charging process to obtain a plurality of power grid side voltage values, a plurality of intermediate loop voltage values and a plurality of intermediate loop current values; wherein
Estimating the actual resistance value and the actual inductance value based on a least square principle from the acquired plurality of grid-side voltage values, plurality of intermediate-loop voltage values, and plurality of intermediate-loop current values.
In an embodiment of the abnormality monitoring method, optionally, the multiple sampling is periodic sampling.
In an embodiment of the foregoing anomaly monitoring method, optionally, the method further includes: establishing a mathematical relation model among the voltage value of the power grid side, the voltage value of the middle loop, the current value of the middle loop, the resistance value of the pre-charging resistor and an inductor of the reactor based on a kirchhoff principle; wherein
Estimating an actual resistance value of the pre-charge resistor and an actual inductance value of the reactor further includes: and estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on a least square principle according to the mathematical relation model.
In an embodiment of the foregoing abnormality monitoring method, optionally, the determining whether the pre-charge resistor and the reactor are abnormal further includes:
respectively calculating a resistance difference value between an actual resistance value and a designed resistance value of the pre-charging resistor and an inductance difference value between an actual inductance value and a designed inductance value of the inductor;
responding to the resistance difference value exceeding the resistance difference value threshold range, and outputting a pre-charging resistance abnormity early warning signal to prompt abnormity of the pre-charging resistance; and
and responding to the condition that the inductance difference value exceeds the inductance difference value threshold range, and outputting an abnormal early warning signal of the reactor to prompt the abnormality of the reactor.
In an embodiment of the foregoing anomaly monitoring method, optionally, the method further includes: repeatedly making the intermediate circuit pass through a plurality of pre-charging processes to obtain a plurality of estimated actual resistance values of the pre-charging resistor and a plurality of estimated actual inductance values of the reactor in response to the fact that neither the pre-charging resistor nor the reactor is abnormal;
determining the resistance difference threshold range according to the estimated actual resistance values of the pre-charging resistors and the designed resistance value; and
and determining the inductance difference threshold range according to the estimated actual inductance values of the reactors and the designed inductance value.
The invention also provides an abnormality monitoring device for the converter, which is used for monitoring a pre-charging resistor and a reactor which are positioned in a middle loop of the converter, wherein the middle loop transmits electric energy on a power grid side to an inversion module of the converter after a pre-charging process, and the abnormality monitoring device specifically comprises a processor and a memory, wherein the processor is configured to:
acquiring a power grid side voltage value, a middle loop voltage value and a middle loop current value in a pre-charging process;
estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on the least square principle according to the acquired voltage value of the power grid side, the voltage value of the middle loop and the current value of the middle loop; and
and comparing the actual resistance value and the designed resistance value of the pre-charging resistor and the actual inductance value and the designed inductance value of the inductor respectively to judge whether the pre-charging resistor and the reactor are abnormal or not.
In an embodiment of the abnormality monitoring device, optionally, the acquiring, by the processor, a grid-side voltage, an intermediate loop voltage, and an intermediate loop current during the pre-charging process further includes: sampling for multiple times in the pre-charging process to obtain a plurality of power grid side voltage values, a plurality of intermediate loop voltage values and a plurality of intermediate loop current values; wherein
The processor estimates the actual resistance value and the actual inductance value based on a least square principle from the acquired plurality of grid-side voltage values, the plurality of intermediate-loop voltage values, and the plurality of intermediate-loop current values.
In an embodiment of the abnormality monitoring apparatus, optionally, the multiple sampling is periodic sampling.
In an embodiment of the abnormality monitoring apparatus, optionally, the processor is further configured to: establishing a mathematical relation model among the voltage value of the power grid side, the voltage value of the middle loop, the current value of the middle loop, the resistance value of the pre-charging resistor and an inductor of the reactor based on a kirchhoff principle; wherein
The processor estimating an actual resistance value of the pre-charge resistor and an actual inductance value of the reactor further includes: and estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on a least square principle according to the mathematical relation model.
In an embodiment of the abnormality monitoring device, optionally, the processor determining whether the pre-charge resistor and the reactor are abnormal further includes:
respectively calculating a resistance difference value between an actual resistance value and a designed resistance value of the pre-charging resistor and an inductance difference value between an actual inductance value and a designed inductance value of the inductor;
responding to the resistance difference value exceeding the resistance difference value threshold range, and outputting a pre-charging resistance abnormity early warning signal to prompt abnormity of the pre-charging resistance; and
and responding to the condition that the inductance difference value exceeds the inductance difference value threshold range, and outputting an abnormal early warning signal of the reactor to prompt the abnormality of the reactor.
In an embodiment of the abnormality monitoring apparatus, optionally, the processor is further configured to: repeatedly making the intermediate circuit pass through a plurality of pre-charging processes to obtain a plurality of estimated actual resistance values of the pre-charging resistor and a plurality of estimated actual inductance values of the reactor in response to the fact that neither the pre-charging resistor nor the reactor is abnormal;
determining the resistance difference threshold range according to the estimated actual resistance values of the pre-charging resistors and the designed resistance value; and
and determining the inductance difference threshold range according to the estimated actual inductance values of the reactors and the designed inductance value.
The present invention also provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of any of the embodiments of the above-described anomaly monitoring method.
According to the converter abnormity monitoring method and device provided by the invention, the related performance of the pre-charging resistor and the reactor in the converter pre-charging loop can be effectively monitored in time, so that an early warning signal can be output in time to remind maintenance personnel to pay attention under the condition that the pre-charging resistor and the reactor are abnormal, the reliability of the pre-charging loop can be improved, and the reliability of the converter can be further improved. The abnormity monitoring device provided by the invention can be compatible and matched with the control device of the existing converter, so that the monitoring cost is not additionally increased, the practicability is realized, and the practicability is higher.
Drawings
The above features and advantages of the present disclosure will be better understood upon reading the detailed description of embodiments of the disclosure in conjunction with the following drawings. In the drawings, components are not necessarily drawn to scale, and components having similar relative characteristics or features may have the same or similar reference numerals.
Fig. 1 shows a schematic structural diagram of a current transformer to which the anomaly monitoring method provided by the present invention is applied.
Fig. 2 shows a simplified circuit structure diagram of the pre-charging resistor and the reactor monitored by the abnormality monitoring method provided by the invention.
Fig. 3 shows a flow chart of an anomaly monitoring method provided by the present invention.
Fig. 4 shows a schematic structural diagram of an anomaly monitoring device provided by the present invention.
Reference numerals
LH1 grid side current sensor
LH2 intermediate loop current sensor
LH16 inverter module current sensor
VH1 grid side voltage sensor
VH2 middle loop voltage sensor
KM1 short-circuit contactor
KM2 charging contact device
FL reactor
R1 pre-charging resistor
R4 resistor
C intermediate capacitance C
Id intermediate loop current
Ud intermediate circuit voltage
Unet grid side voltage
400 abnormity monitoring device
401 processor
402 memory
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. It is noted that the aspects described below in connection with the figures and the specific embodiments are only exemplary and should not be construed as imposing any limitation on the scope of the present invention.
First, refer to fig. 1 to understand a schematic structural diagram of a current transformer applied in the anomaly monitoring method provided by the present invention. As shown in fig. 1, the converter includes an intermediate circuit and an inverter module, wherein the intermediate circuit is connected to the grid side and transmits the electric energy of the grid side to the inverter module at the rear end. In the following description, the converter provided by the present invention is mainly used for providing tractive force for an urban rail train, i.e. a traction converter. Of course, those skilled in the art should appreciate that the converter used in the above converter anomaly monitoring method is not limited to providing tractive power for an urban rail train. It is to be understood that the converter shown in fig. 1 is merely schematic and that the complete converter structure may further comprise various electrical components in detail for the purpose of implementing the relevant functions of the converter, which are not shown, but do not mean that they do not exist in practice.
The abnormality monitoring method provided by the invention is mainly used for monitoring the abnormality of the pre-charging resistor R1 and the reactor FL in the middle loop. As can be seen from the circuit configuration diagram shown in fig. 1, the pre-charging resistor R1 functions to limit the magnitude of the charging current when the charging contact KM2 is closed and then charges the intermediate capacitor C, so as to avoid direct impact of a large current on the intermediate capacitor C. The reactor FL and the intermediate capacitor C form an LC filter loop (may further include a resistor R4), so as to filter out ripples in the intermediate loop voltage and maintain the stability of the intermediate loop voltage. If the pre-charging resistor R1 is abnormal, it is mainly reflected that the resistance of the pre-charging resistor R1 is increased or decreased, and the resistance of the pre-charging resistor R1 is decreased, so that the function of limiting the charging current in the initial stage of the charging process is decreased, and the middle capacitor C may be frequently impacted by a large current to affect the performance; when the pre-charging resistor R1 becomes larger, the progress of the charging process is influenced, and if the charging process is too slow, even the train protection action is caused, and the normal operation of the train is influenced. If the electric reactor FL is abnormal, the filtering effect is influenced no matter the electric reactor FL is enlarged or reduced, so that the stability of the voltage of the intermediate circuit is reduced, and the whole traction transmission system can be influenced. Therefore, when the pre-charging resistor R1 and the reactor FL are abnormal, both the pre-charging resistor R1 and the reactor FL affect the normal operation of the train.
Since the present invention is expected to provide an abnormality monitoring method for monitoring the performance of the pre-charging resistor and the reactor during the operation of the train, that is, during the on-line operation of the converter, and the pre-charging resistor and the reactor play a main role during the pre-charging process according to the above description, the abnormality monitoring method provided by the present invention firstly needs to judge whether the converter starts to operate normally, and the intermediate circuit is in the pre-charging process. The normal operation mainly means that no fault is reported in the converter starting process, such as a main card breaking and separating fault, a charging contact clamping and separating fault, a clamping fault and the like), and if the fault is not reported, the intermediate circuit is judged to be in the pre-charging process. As can be seen from the circuit diagram shown in fig. 1, the starting time of the precharge process may be considered as the time at which the charging contact KM2 starts to close, and the ending time of the precharge process may be considered as the time at which the shorting contact KM1 starts to close. That is, the starting time T _ start of the traction converter precharge process may be determined as the time when the feedback of the closed state of the charging contactor KM2 is valid, and the ending time T _ end of the traction converter precharge process may be determined as the time when the closing control command of the shorting contactor KM1 is valid.
Please refer to fig. 3 together to understand the detailed steps of the anomaly monitoring method provided by the present invention. As shown in fig. 3, in step S100, since the pre-charge process of the traction converter can be determined by determining the starting time T _ start and the end time T _ end of the pre-charge process of the traction converter, the grid-side voltage value Unet, the intermediate circuit voltage value Ud and the intermediate circuit current value Id during the pre-charge process, i.e. during the time period from the time T _ start to the time T _ end, are then obtained. Referring to fig. 1, in the control system of the existing converter, the overall performance of the converter can be monitored by providing various sensors, such as a grid-side current sensor LH1, a middle-loop current sensor LH2, an inverter module current sensor LH16, a grid-side voltage sensor VH1, a middle-loop voltage sensor VH2, and the like. Here, the grid-side voltage value uet may be acquired by the grid-side voltage sensor VH1, the intermediate circuit voltage value Ud may be acquired by the intermediate circuit voltage sensor VH2, and the intermediate circuit current value Id may be acquired by the intermediate circuit current sensor LH 2.
In a preferred embodiment, the abnormality monitoring method provided by the present invention obtains a plurality of grid-side voltage values uet, intermediate circuit voltage values Ud, and intermediate circuit current values Id by sampling a plurality of times during the precharging process. More preferably, the plurality of samples are periodic samples, that is, in step S100, the grid-side voltage value uet (ti), the intermediate circuit voltage value ud (ti), and the intermediate circuit current value id (ti) are obtained at each sampling time, where ti is T _ start, T _ start + T, …, T _ start + n T, …, and T _ end, and T is a sampling period, and in one embodiment, is 40 microseconds. It should be understood that the above-mentioned sampling period T of 40 microseconds is only an illustration, and those skilled in the art can adjust the time of the above-mentioned sampling period according to actual needs, and the protection scope of the present invention should not be limited properly.
Subsequently, in step S200, the actual resistance value of the precharge resistor R1 and the actual inductance value of the reactor FL are estimated based on the principle of least squares from the acquired grid-side voltage value uet (ti), intermediate circuit voltage value ud (ti), and intermediate circuit current value id (ti). It will be appreciated that for a normally operating circuit, the actual values of its pre-charge resistor R1 and reactor FL are actually determined. However, the actual values of the pre-charging resistor R1 and the reactor FL cannot be monitored in real time during normal operation of the converter, especially during pre-charging, and therefore, the present invention provides an estimation method to monitor the actual values of the pre-charging resistor R1 and the reactor FL.
In this step, the anomaly monitoring method provided by the invention further comprises the step of establishing a mathematical relationship model among the grid-side voltage value, the intermediate circuit current value, the resistance value of the pre-charging resistor and the inductor of the reactor based on kirchhoff principle so as to provide possibility for smoothly estimating the actual values of the pre-charging resistor R1 and the reactor FL. In this step, first, referring to fig. 2, the difficulty of establishing the mathematical relationship model can be reduced by simplifying the circuit structure diagram during the precharge process. In the process of pre-charging, the rear inverter module (mainly an IGBT (insulated gate bipolar transistor)) is not started, so that the rear inverter module part can be not considered, the front end is connected with a power grid and equivalently provides a power supply for the intermediate circuit, and therefore the front end of the intermediate circuit can be simplified into one power supply (the voltage is the power grid side voltage Unet).
Further analyzing fig. 2, a relation model between the pre-charging resistor R1, the reactor FL, the grid-side voltage uet, the intermediate circuit current Id, and the intermediate circuit voltage Ud during the charging process can be obtained according to kirchhoff's principle, as shown in formula (1):
wherein R is11Characterizing the resistance, L, of the pre-charge resistor R11The inductance value of the reactor FL is characterized,the same applies in the subsequent equations.
It will be appreciated by those skilled in the art that Kirchhoff law (Kirchhoff laws) is the fundamental law followed by voltage and current in a circuit, and is the basis for analyzing and calculating a more complex circuit, from which Kirchhoff current law (KCL, the sum of all currents into a node equals the sum of all currents out of this node) and Kirchhoff voltage law (KVL, the algebraic sum of the potential differences (voltages) across all elements along a closed loop equals zero) a model of the relationship between the pre-charge resistor R1, the reactor FL and the grid-side voltage uet, the intermediate loop current Id, the intermediate loop voltage Ud during charging can be derived.
Since Unet, Id, Ud have been obtained in step S100, the resistance value R of the pre-charge resistor R1 can be obtained according to the formula (1)11Inductance value L of reactor FL1And (7) identifying. Further, in a more preferred embodiment of step S100, the resistance R identifying the plurality of pre-charge resistors R1 according to formula (1) can be obtained by periodically sampling for a plurality of times11And inductance values L of the plurality of reactors FL1Therefore, data acquisition errors caused by voltage and current fluctuation in the pre-charging process are reduced. Furthermore, in order to more accurately estimate the resistance R of the pre-charge resistor R111And inductance value L of reactor FL1The monitoring method provided by the invention is used for monitoring the resistance value R of the pre-charging resistor R1 by the least square principle11And inductance values L of the plurality of reactors FL1And (5) performing identification.
Least squares (also known as the least squares method) is a mathematical optimization technique. It finds the best functional match of the data by minimizing the sum of the squares of the errors. Unknown data can be easily obtained by the least square method, and the sum of squares of errors between these obtained data and actual data is minimized. That is, the resistance value R of the pre-charge resistor R1 obtained by the least square method11And inductance value L of reactor FL1The actual resistance value closest to the precharge resistor R1 and the actual inductance value of the reactor FL.
A mathematical relationship model between the pre-charging resistor R1, the reactor FL, and the grid-side voltage uet, the intermediate circuit current Id, and the intermediate circuit voltage Ud during the charging process will be further embodied by the principle of least squares.
First, an expression of deviation (sum of squares of errors) as shown in equation (2) is obtained:
according to the least square principle, to estimate the resistance value R of the pre-charge resistor R111And inductance value L of reactor FL1It is desirable to minimize the deviation D, and to achieve this goal D vs R are calculated separately11D to L1Partial differential of
And make
This results in the system of equations shown in equation (3),
solving the equation set in the formula (3) to obtain the resistance value R of the pre-charging resistor11Is estimated value of
Is shown in formula (4), and the inductance value L of the reactor FL1Is estimated value of
Is shown in equation (5).
Wherein a1, a2, a3, a4, b1 and b2 are shown in formulas (6) to (11) respectively
Unet (t) in the above formulai)、Ud(ti)、Id(ti) Respectively represent the t-thiSampling values of a power grid side voltage value, a middle loop voltage value and a middle loop current value at the moment,
then it means tiTime IdCan be expressed by equation (12):
t in equation (12) represents a sampling period, which may be set to 40 microseconds in the above-described embodiment, as needed.
Therefore, after the model of the relationship between the pre-charging resistor R1, the reactor FL, and the grid-side voltage uet, the intermediate circuit current Id, and the intermediate circuit voltage Ud during charging has been specified according to the least squares principle, it is only necessary to specify the grid-side voltage uet (t) acquired in step S100i) Intermediate circuit current Id (t)i) Intermediate circuit voltage Ud (t)i) Substituting into equations (4) - (12) to obtain the estimated value of the pre-charge resistance
And estimated value of inductance value of reactor
Subsequently, in step S300, the actual estimated value of the pre-charge resistor and the design value and the actual estimated value of the reactor and the design value are compared to determine whether the pre-charge resistor and the reactor are abnormal.
Specifically, in one embodiment, the comparison is performed by calculating a resistance difference Δ R between the actual estimated value of the pre-charge resistance and the design resistance Rs (see equation 13), and by calculating an inductance difference Δ L between the actual estimated value of the inductor and the design inductance Ls (see equation 14).
And then, judging whether the resistance difference value delta R exceeds the resistance difference value threshold range, responding to the fact that the resistance difference value delta R exceeds the resistance difference value threshold range, and outputting a pre-charging resistance abnormity early warning signal to prompt abnormity of the pre-charging resistance. And judging whether the inductance difference value delta L exceeds the inductance difference value threshold range, responding to the fact that the inductance difference value delta L exceeds the inductance difference value threshold range, and outputting an abnormal early warning signal of the reactor to prompt the abnormity of the reactor.
Furthermore, in another preferred embodiment, the monitoring method provided by the present invention further includes a step of determining a resistance difference threshold range and an inductance difference threshold range. Specifically, in a case where it has been determined that neither the pre-charge resistor nor the reactor is abnormal, the intermediate circuit may be repeatedly subjected to a plurality of pre-charge processes to obtain a plurality of estimated actual resistance values of the pre-charge resistor and a plurality of estimated actual inductance values of the reactor. Specifically, the estimated actual resistance value of the pre-charge resistor and the estimated actual inductance value of the reactor are obtained in each pre-charge process according to the kirchhoff principle and the least-square principle described above.
Although the resistance value of the pre-charge resistor and the inductance value of the reactor are estimated more accurately according to the monitoring method provided by the invention, the deviation between the estimated value and the true value still cannot be avoided due to the existence of the physical limit. Therefore, multiple groups of data need to be acquired, and the distribution range of the deviation between the estimated value and the true value is obtained under the condition that the pre-charging resistor and the reactor are both normal, so that the resistance difference value threshold range and the inductance difference value threshold range are determined.
In the embodiment, the method for setting the resistance difference threshold range and the inductance difference threshold range can not only ensure that the abnormity of the pre-charging resistor and the reactor can be early warned in time, but also ensure that a certain fault tolerance rate exists, and avoid the problem that the false alarm causes trouble to maintenance personnel on the contrary.
According to the abnormity monitoring method provided by the invention, a relation model among the pre-charging resistor, the reactor, the voltage of the power grid side, the current of the intermediate loop and the voltage of the intermediate loop in the charging process is established for the pre-charging resistor and the reactor of the urban rail traction converter based on a circuit principle. The method comprises the steps of identifying the resistance value of a pre-charging resistor and the inductance value of a reactor in each charging process by utilizing a least square principle and collected sampling values of the voltage of the side of a power grid, the voltage of a middle loop and the current of the middle loop in the charging process, obtaining an estimated value of the inductance value of the reactor of the resistance value of the pre-charging resistor, and realizing early warning of the abnormality of the pre-charging resistor and the reactor of the urban rail traction converter by comparing the estimated value and the designed value of the resistance value of the pre-charging resistor and comparing.
The invention also provides an abnormality monitoring device for the converter, please refer to fig. 4, and fig. 4 shows a schematic diagram of the abnormality monitoring device. As shown in fig. 4, the anomaly monitoring device 400 includes a processor 401 and a memory 402. The processor 401 of the abnormality monitoring apparatus 400 can implement the above-described abnormality monitoring method when executing the computer program stored in the memory 402, for which reference is specifically made to the above description of the abnormality monitoring method, which is not described herein again.
The present invention also provides a computer storage medium having stored thereon a computer program which, when executed by a processor, carries out the steps of the above-described anomaly monitoring method.
Furthermore, since a control device already exists in the current traction converter to control the related actions of the traction converter, and the control device can already realize the time for acquiring the closing state of the charging contactor and the shorting contactor, for example, various sensors are arranged to sense the current amount and the voltage amount, etc., the abnormality monitoring device provided by the present invention can be the existing control device, and only the computer storage medium provided by the present invention to realize the above abnormality monitoring method needs to be loaded on the control device.
The invention provides an abnormity monitoring method aiming at a pre-charging resistor and a reactor of an urban rail traction converter, and the method has the advantages of simplicity, easiness in implementation, no need of additionally adding equipment, low cost and capability of quickly and timely judging the existence of the abnormal pre-charging resistor and the abnormal reactor.
The anomaly monitoring method and apparatus provided by the present invention have been described so far. Those of skill in the art would understand that information, signals, and data may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits (bits), symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the description of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "mounted" and "coupled" are to be construed broadly, e.g., as meaning fixedly attached, detachably attached, or integrally attached; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The various illustrative logical modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk (disk) and disc (disc), as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks (disks) usually reproduce data magnetically, while discs (discs) reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (13)
1. An abnormity monitoring method of a converter is used for monitoring a pre-charging resistor and a reactor which are positioned in a middle loop of the converter, the middle loop transmits electric energy on a power grid side to an inversion module of the converter after a pre-charging process, and the method is characterized by comprising the following steps:
acquiring a power grid side voltage value, a middle loop voltage value and a middle loop current value in a pre-charging process;
estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on the least square principle according to the acquired power grid side voltage value, the intermediate circuit voltage value and the intermediate circuit current value; and
and respectively comparing the actual resistance value and the designed resistance value of the pre-charging resistor and the actual inductance value and the designed inductance value of the inductor to judge whether the pre-charging resistor and the reactor are abnormal.
2. The anomaly monitoring method according to claim 1, wherein said obtaining a grid-side voltage, an intermediate loop voltage and an intermediate loop current during a pre-charge further comprises: sampling for multiple times in the pre-charging process to obtain a plurality of power grid side voltage values, a plurality of intermediate circuit voltage values and a plurality of intermediate circuit current values; wherein
Estimating the actual resistance value and the actual inductance value based on a least square principle from the acquired plurality of grid-side voltage values, plurality of intermediate-loop voltage values, and plurality of intermediate-loop current values.
3. The anomaly monitoring method according to claim 2, wherein said plurality of samplings are periodic samplings.
4. The anomaly monitoring method according to claim 1, further comprising: establishing a mathematical relation model among the voltage value of the power grid side, the voltage value of the middle loop, the current value of the middle loop, the resistance value of the pre-charging resistor and an inductor of the reactor based on a kirchhoff principle; wherein
Estimating an actual resistance value of the pre-charge resistor and an actual inductance value of the reactor further comprises: and estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on the least square principle according to the mathematical relation model.
5. The abnormality monitoring method according to claim 1, wherein said judging whether or not said pre-charge resistor and said reactor are abnormal further comprises:
respectively calculating a resistance difference value between an actual resistance value and a designed resistance value of the pre-charging resistor and an inductance difference value between an actual inductance value and a designed inductance value of the inductor;
responding to the resistance difference value exceeding the resistance difference value threshold range, and outputting a pre-charging resistance abnormity early warning signal to prompt abnormity of the pre-charging resistance; and
and responding to the condition that the inductance difference value exceeds the inductance difference value threshold range, and outputting an abnormal early warning signal of the reactor to prompt the abnormality of the reactor.
6. The anomaly monitoring method according to claim 5, further comprising: repeatedly subjecting the intermediate circuit to a plurality of pre-charging processes to obtain a plurality of estimated actual resistance values of the pre-charging resistors and a plurality of estimated actual inductance values of the reactors in response to no abnormality in both the pre-charging resistors and the reactors;
determining the resistance difference threshold range according to the estimated actual resistance values of the pre-charging resistors and the design resistance value; and
determining the inductance difference threshold range according to a plurality of estimated actual inductance values of the reactor and the design inductance value.
7. An abnormality monitoring device for a converter, which is used for monitoring a pre-charging resistor and a reactor which are positioned in an intermediate circuit of the converter, wherein the intermediate circuit transfers electric energy on a power grid side to an inversion module of the converter after a pre-charging process, and the abnormality monitoring device is characterized by comprising a processor and a memory, wherein the processor is configured to:
acquiring a power grid side voltage value, a middle loop voltage value and a middle loop current value in a pre-charging process;
estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on the least square principle according to the acquired power grid side voltage value, the intermediate circuit voltage value and the intermediate circuit current value; and
and respectively comparing the actual resistance value and the designed resistance value of the pre-charging resistor and the actual inductance value and the designed inductance value of the inductor to judge whether the pre-charging resistor and the reactor are abnormal.
8. The anomaly monitoring device according to claim 7, wherein said processor obtaining a grid-side voltage, an intermediate loop voltage and an intermediate loop current during a pre-charge further comprises: sampling for multiple times in the pre-charging process to obtain a plurality of power grid side voltage values, a plurality of intermediate circuit voltage values and a plurality of intermediate circuit current values; wherein
The processor estimates the actual resistance value and the actual inductance value based on a least square principle from the acquired plurality of grid-side voltage values, plurality of intermediate-loop voltage values, and plurality of intermediate-loop current values.
9. The anomaly monitoring device according to claim 8, wherein said plurality of samplings are periodic samplings.
10. The anomaly monitoring device of claim 7, wherein said processor is further configured to: establishing a mathematical relation model among the voltage value of the power grid side, the voltage value of the middle loop, the current value of the middle loop, the resistance value of the pre-charging resistor and an inductor of the reactor based on a kirchhoff principle; wherein
The processor estimating an actual resistance value of the pre-charge resistor and an actual inductance value of the reactor further comprises: and estimating the actual resistance value of the pre-charging resistor and the actual inductance value of the reactor based on the least square principle according to the mathematical relation model.
11. The abnormality monitoring device according to claim 7, wherein said processor determining whether said pre-charge resistor and said reactor are abnormal further includes:
respectively calculating a resistance difference value between an actual resistance value and a designed resistance value of the pre-charging resistor and an inductance difference value between an actual inductance value and a designed inductance value of the inductor;
responding to the resistance difference value exceeding the resistance difference value threshold range, and outputting a pre-charging resistance abnormity early warning signal to prompt abnormity of the pre-charging resistance; and
and responding to the condition that the inductance difference value exceeds the inductance difference value threshold range, and outputting an abnormal early warning signal of the reactor to prompt the abnormality of the reactor.
12. The anomaly monitoring device of claim 11, wherein said processor is further configured to: repeatedly subjecting the intermediate circuit to a plurality of pre-charging processes to obtain a plurality of estimated actual resistance values of the pre-charging resistors and a plurality of estimated actual inductance values of the reactors in response to no abnormality in both the pre-charging resistors and the reactors;
determining the resistance difference threshold range according to the estimated actual resistance values of the pre-charging resistors and the design resistance value; and
determining the inductance difference threshold range according to a plurality of estimated actual inductance values of the reactor and the design inductance value.
13. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the anomaly monitoring method according to any one of claims 1-6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910915591.8A CN112557779B (en) | 2019-09-26 | 2019-09-26 | Converter abnormity monitoring method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910915591.8A CN112557779B (en) | 2019-09-26 | 2019-09-26 | Converter abnormity monitoring method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112557779A true CN112557779A (en) | 2021-03-26 |
| CN112557779B CN112557779B (en) | 2022-03-25 |
Family
ID=75029742
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910915591.8A Active CN112557779B (en) | 2019-09-26 | 2019-09-26 | Converter abnormity monitoring method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112557779B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113479100A (en) * | 2021-07-13 | 2021-10-08 | 国创移动能源创新中心(江苏)有限公司 | Direct current fills electric pile direct current bus monitoring system and direct current fills electric pile |
Citations (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2051468A1 (en) * | 2007-06-25 | 2009-04-22 | Deutsche Telekom AG | Method, data processing device and computer network for anomaly detection |
| CN102159421A (en) * | 2008-09-22 | 2011-08-17 | 丰田自动车株式会社 | Abnormality detector of vehicle and vehicle |
| CN103018575A (en) * | 2012-12-05 | 2013-04-03 | 合肥工业大学 | High-power inductance testing device, main circuit thereof and testing method thereof |
| JP2013170872A (en) * | 2012-02-20 | 2013-09-02 | Shimadzu Corp | Optical particle measuring apparatus |
| CN103278692A (en) * | 2013-05-06 | 2013-09-04 | 北京天诚同创电气有限公司 | Method for detecting brake circuit of wind power generation converter |
| CN104166083A (en) * | 2014-08-14 | 2014-11-26 | 北京天诚同创电气有限公司 | Fault detection method and device for IGBT (insulated gate bipolar transistor) reverse parallel diode |
| KR20150055223A (en) * | 2013-11-13 | 2015-05-21 | 현대모비스 주식회사 | Method for processing signal for Operating Electronic Controlled Suspension and Apparatus for the same |
| CN104890525A (en) * | 2014-03-06 | 2015-09-09 | 福特全球技术公司 | Capacitor precharging and capacitance/resistance measurement in electric vehicle drive system |
| CN105044470A (en) * | 2015-06-30 | 2015-11-11 | 同济大学 | Method for detecting DC capacity of current transformer based on resonance principles |
| CN105067927A (en) * | 2015-08-11 | 2015-11-18 | 清能德创电气技术（北京）有限公司 | Servo driver brake resistor loop detection method |
| CN105467259A (en) * | 2015-11-16 | 2016-04-06 | 上海天马微电子有限公司 | Detection circuit for detecting capacitance sensing line, capacitive touch screen and detection method |
| CN106096298A (en) * | 2016-06-20 | 2016-11-09 | 重庆大学 | Transducer parameters on-line identification method based on observer |
| CN107132440A (en) * | 2017-05-23 | 2017-09-05 | 江苏现代电力科技股份有限公司 | A kind of power electronics type reactor performance testing device |
| CN108226652A (en) * | 2017-12-29 | 2018-06-29 | 北京金风科创风电设备有限公司 | Real-time detection method, device and equipment for direct-current support capacitor of converter |
| CN109084813A (en) * | 2017-06-13 | 2018-12-25 | 发那科株式会社 | Have the function of adjusting the encoder and its control method of the threshold value of comparator |
| CN110248811A (en) * | 2017-04-05 | 2019-09-17 | 惠普发展公司，有限责任合伙企业 | It is assessed using actuator on the tube core of the threshold value of precharge |
| CN110275068A (en) * | 2018-03-16 | 2019-09-24 | 广州小鹏汽车科技有限公司 | A kind of capacitor capacitance detection method and equipment |
-
2019
- 2019-09-26 CN CN201910915591.8A patent/CN112557779B/en active Active
Patent Citations (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2051468A1 (en) * | 2007-06-25 | 2009-04-22 | Deutsche Telekom AG | Method, data processing device and computer network for anomaly detection |
| CN102159421A (en) * | 2008-09-22 | 2011-08-17 | 丰田自动车株式会社 | Abnormality detector of vehicle and vehicle |
| JP2013170872A (en) * | 2012-02-20 | 2013-09-02 | Shimadzu Corp | Optical particle measuring apparatus |
| CN103018575A (en) * | 2012-12-05 | 2013-04-03 | 合肥工业大学 | High-power inductance testing device, main circuit thereof and testing method thereof |
| CN103278692A (en) * | 2013-05-06 | 2013-09-04 | 北京天诚同创电气有限公司 | Method for detecting brake circuit of wind power generation converter |
| KR20150055223A (en) * | 2013-11-13 | 2015-05-21 | 현대모비스 주식회사 | Method for processing signal for Operating Electronic Controlled Suspension and Apparatus for the same |
| CN104890525A (en) * | 2014-03-06 | 2015-09-09 | 福特全球技术公司 | Capacitor precharging and capacitance/resistance measurement in electric vehicle drive system |
| CN104166083A (en) * | 2014-08-14 | 2014-11-26 | 北京天诚同创电气有限公司 | Fault detection method and device for IGBT (insulated gate bipolar transistor) reverse parallel diode |
| CN105044470A (en) * | 2015-06-30 | 2015-11-11 | 同济大学 | Method for detecting DC capacity of current transformer based on resonance principles |
| CN105067927A (en) * | 2015-08-11 | 2015-11-18 | 清能德创电气技术（北京）有限公司 | Servo driver brake resistor loop detection method |
| CN105467259A (en) * | 2015-11-16 | 2016-04-06 | 上海天马微电子有限公司 | Detection circuit for detecting capacitance sensing line, capacitive touch screen and detection method |
| CN106096298A (en) * | 2016-06-20 | 2016-11-09 | 重庆大学 | Transducer parameters on-line identification method based on observer |
| CN110248811A (en) * | 2017-04-05 | 2019-09-17 | 惠普发展公司，有限责任合伙企业 | It is assessed using actuator on the tube core of the threshold value of precharge |
| CN107132440A (en) * | 2017-05-23 | 2017-09-05 | 江苏现代电力科技股份有限公司 | A kind of power electronics type reactor performance testing device |
| CN109084813A (en) * | 2017-06-13 | 2018-12-25 | 发那科株式会社 | Have the function of adjusting the encoder and its control method of the threshold value of comparator |
| CN108226652A (en) * | 2017-12-29 | 2018-06-29 | 北京金风科创风电设备有限公司 | Real-time detection method, device and equipment for direct-current support capacitor of converter |
| CN110275068A (en) * | 2018-03-16 | 2019-09-24 | 广州小鹏汽车科技有限公司 | A kind of capacitor capacitance detection method and equipment |
Non-Patent Citations (4)
| Title |
|---|
| R. YAHYAOUI 等: "Signal Processing-Based Switch Fault Detection Methods for Multi-Phase Interleaved Boost Converter", 《2017 IEEE VEHICLE POWER AND PROPULSION CONFERENCE (VPPC)》 * |
| 唐黎哲 等: "基于小波分析和深度信念网络的牵引系统故障诊断", 《控制与信息技术》 * |
| 李晨 等: "一种基于深度卷积神经网络的牵引变流器故障诊断技术", 《控制与信息技术》 * |
| 陈广泰: "机车牵引变流器预充电电阻的参数设计与仿真", 《内燃机车》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113479100A (en) * | 2021-07-13 | 2021-10-08 | 国创移动能源创新中心(江苏)有限公司 | Direct current fills electric pile direct current bus monitoring system and direct current fills electric pile |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112557779B (en) | 2022-03-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5400732B2 (en) | Parameter estimation device | |
| CN102122810B (en) | Current diagnosing device and method for monitoring state of current transformer | |
| Lin et al. | Voltage-correlation based multi-fault diagnosis of lithium-ion battery packs considering inconsistency | |
| EP2619604B1 (en) | Method for checking the proper method of operation of a current sensor | |
| CN112345917B (en) | Method and device for monitoring converter direct current loop abnormity | |
| CN103383423B (en) | The method and system of the defect on the DC electric wire of detection power converter | |
| CN112345955B (en) | Multi-fault online diagnosis method and system for power battery | |
| CN112557779B (en) | Converter abnormity monitoring method and device | |
| CN112782614A (en) | Fault early warning method and device of converter based on multi-information fusion | |
| CN112100945A (en) | Ground short circuit detection method, motor controller and computer readable storage medium | |
| KR20240063928A (en) | Battery system health status monitoring system | |
| CN104236933B (en) | A kind of potential faults method for early warning for train traction system | |
| CN112782499B (en) | Multi-information fusion-based converter state evaluation method and device | |
| CN115144765A (en) | Method and device for detecting short-circuit fault in battery | |
| CN103427405A (en) | Differential protection method on basis of high-order cumulants for power transmission line | |
| Liu et al. | A novel method for fault diagnosis and type identification of cell voltage inconsistency in electric vehicles using weighted Euclidean distance evaluation and statistical analysis | |
| CN106450532A (en) | Method for improving voltage sampling precision of single battery in charge equalization | |
| Tang et al. | An aging-and load-insensitive method for quantitatively detecting the battery internal-short-circuit resistance | |
| CN111289921B (en) | Non-contact power device open-circuit fault high-speed detection system and method | |
| CN102590694B (en) | A kind of double circuits on same tower transmission line of electricity internal fault external fault Simulation after test recognition methods based on lumped parameter T model | |
| CN205176191U (en) | Transformer winding deformation test system | |
| CN104930963A (en) | Impedance circle characteristic-based transformer winding deformation discrimination method | |
| CN108732523B (en) | Fault diagnosis method for intermediate voltage sensor under high-voltage working condition of direct-current power supply transmission system | |
| CN113113942A (en) | Voltage-based short circuit detection by an onboard vehicle battery charger | |
| CN112470013A (en) | Electric vehicle charging monitoring device and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |