A contactor state recognition method and device

Abstract

The application discloses a contactor state recognition method and device, recognizes contactor state information, determines a contactor state threshold based on a pressure difference integral of the contactor in a first integral period, determines a contactor state value based on a pressure difference integral of the contactor in a second integral period, obtains a contactor state recognition result based on the contactor state information and a size relation between the contactor state value and the contactor state threshold. In the application, the contactor state threshold and the contactor state value are obtained by using the contactor pressure difference integral, the recognition of all contactor states can be realized, especially the recognition of the contactor state after the contactor of the capacitive load is disconnected. The contactor state threshold is obtained by using the contactor pressure difference integral in the first integral period before the contactor state is switched, the influence of the contactor temperature and sampling error can be excluded, and the recognition reliability is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of contactors, and more particularly to a contactor state recognition method and device. BACKGROUND

[0002] At present, each system in a medium and high voltage power distribution system, such as a vehicle system, a power battery system, a charging pile, and the like, controls the connection between an electrical equipment and a power source by controlling the on-off of a contactor. Therefore, the contactor is crucial in the medium and high voltage power distribution system. The recognition of the state of the contactor is directly related to the safe and reliable operation of the medium and high voltage power distribution system. Accurate recognition of the state of the contactor can reduce the product failure rate and maintenance cost, increase the core competitiveness of the product, and improve the enterprise image.

[0003] Therefore, how to provide a contactor state recognition method and device becomes a technical problem to be solved by those skilled in the art. SUMMARY

[0004] Therefore, the present application discloses a contactor state recognition method and device to realize the recognition of the state of the contactor.

[0005] A contactor state recognition method comprises the following steps.

[0006] recognizing contactor state information;

[0007] determining a contactor state threshold value based on a differential pressure integral of the contactor in a first integral period, wherein the first integral period is a period before the state of the contactor is switched;

[0008] determining a contactor state value based on a differential pressure integral of the contactor in a second integral period, wherein the second integral period is a period after the state of the contactor is switched;

[0009] obtaining a contactor state recognition result based on the contactor state information and the size relationship between the contactor state value and the contactor state threshold value.

[0010] Optionally, the contactor state information is contactor opening or contactor closing.

[0011] Optionally, the obtaining of the contactor state recognition result based on the contactor state information and the size relationship between the contactor state value and the contactor state threshold value comprises the following steps.

[0012] determining a differential pressure theoretical value before and after the action of the contactor according to the contactor state information;

[0013] calculating the difference between the contactor state value and the contactor state threshold value;

[0014] determining whether the difference value is consistent with the pressure difference theoretical value;

[0015] If yes, determining that the contactor state recognition result is a contactor normal state.

[0016] If no, determining that the contactor state recognition result is a contactor fault state.

[0017] Optionally, the determining that the contactor state recognition result is a contactor normal state comprises:

[0018] If the contactor state information is a contactor closed state, and the contactor state threshold value is less than the contactor state value, it is determined that the contactor state recognition result is a contactor normal closed state.

[0019] Optionally, the determining that the contactor state recognition result is a contactor normal state comprises:

[0020] If the contactor state information is a contactor open state, and the contactor state threshold value is greater than the contactor state value, it is determined that the contactor state recognition result is a contactor normal open state.

[0021] Optionally, the determining that the contactor state recognition result is a contactor fault state comprises:

[0022] If the contactor state information is a contactor closed state, and the contactor state threshold value is greater than the contactor state value, it is determined that the contactor state recognition result is a contactor sticking fault state.

[0023] Optionally, the determining that the contactor state recognition result is a contactor fault state comprises:

[0024] If the contactor state information is a contactor open state, and the contactor state threshold value is less than the contactor state value, it is determined that the contactor state recognition result is a contactor breaking fault state.

[0025] Optionally, the contactor state threshold value is a pressure difference integral value or a pressure difference integral average value.

[0026] Optionally, the contactor state value is a pressure difference integral value or a pressure difference integral average value.

[0027] Optionally, when the back-end load of the contactor is resistive, the first integral time period and the second integral time period are both determined based on a contactor voltage sampling time interval.

[0028] Optionally, when the back-end load of the contactor is capacitive, the first integral time period and the second integral time period are both determined according to a capacitive load voltage rising curve or a capacitive load voltage decay curve.

[0029] Optionally, the first integration period and the second integration period are determined based on a sleep power-off time of the electrical apparatus.

[0030] A contactor state recognition apparatus, comprising:

[0031] an information recognition unit configured to recognize contactor state information;

[0032] a state threshold value determination unit configured to determine a contactor state threshold value based on a pressure differential integration of the contactor in a first integration period, wherein the first integration period is a period before a contactor state switch;

[0033] a state value determination unit configured to determine a contactor state value based on a pressure differential integration of the contactor in a second integration period, wherein the second integration period is a period after the contactor state switch;

[0034] a state recognition unit configured to obtain a contactor state recognition result based on the contactor state information, and a size relationship between the contactor state value and the contactor state threshold value.

[0035] Optionally, the state recognition unit comprises:

[0036] a theoretical value determination sub-unit configured to determine a pressure differential theoretical value before and after an action of the contactor according to the contactor state information;

[0037] a calculation sub-unit configured to calculate a difference value between the contactor state value and the contactor state threshold value;

[0038] a judgment sub-unit configured to judge whether the difference value is consistent with the pressure differential theoretical value;

[0039] a normal determination sub-unit configured to determine that the contactor state recognition result is a contactor normal in a case where the judgment sub-unit judges yes;

[0040] a fault determination sub-unit configured to determine that the contactor state recognition result is a contactor fault in a case where the judgment sub-unit judges no.

[0041] From the above technical solution can be known, the application discloses a kind of contactor state identification method and device, identify contactor state information, determine contactor state threshold based on the pressure difference integration of contactor in first integration period, determine contactor state value based on the pressure difference integration of contactor in second integration period, based on contactor state information, and the size relationship of contactor state value and contactor state threshold, obtain contactor state identification result.In the present application, contactor state threshold and contactor state value are obtained using contactor pressure difference integration, which can realize the identification of all contactor states, especially the contactor of capacitive load after disconnection, in the case of slowly declining capacitor voltage, the identification of contactor state.In addition, the contactor state in the first integration period and the second integration period is different, that is, the first integration time period and the second integration time period are different time periods before and after the contactor state switches, and the contactor state threshold uses the pressure difference integration in the first integration period before the contactor state switches, which can exclude the influence of contactor temperature and sampling error and other factors, and improve the reliability of contactor state identification. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the disclosed drawings without creative labor.

[0043] Figure 1 A flow chart of a contactor state identification method disclosed by the embodiments of the present application is shown in Figure 1.

[0044] Figure 2 A pressure difference waveform diagram of a contactor from closed to disconnected disclosed by the embodiments of the present application is shown in Figure 2.

[0045] Figure 3 A schematic diagram of voltage sampling before and after the contactor disclosed by the embodiments of the present application is shown in Figure 3.

[0046] Figure 4 A schematic diagram of a contactor state identification device disclosed by the embodiments of the present application is shown in Figure 4.

[0047] Figure 5 A capacitive load voltage rising curve diagram disclosed by the embodiments of the present application is shown in Figure 5.

[0048] Figure 6 A capacitive load voltage decay curve diagram disclosed by the embodiments of the present application is shown in Figure 6.

[0049] Figure 7 A schematic diagram of a contactor state identification device disclosed by the embodiments of the present application is shown in Figure 4. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0051] The embodiment of the present application discloses a contactor state recognition method and device, specifically, the method comprises the following steps: recognizing contactor state information, determining a contactor state threshold value based on a differential pressure integral of the contactor in a first integral period, determining a contactor state value based on a differential pressure integral of the contactor in a second integral period, obtaining a contactor state recognition result based on the contactor state information and the size relationship between the contactor state value and the contactor state threshold value. In the present application, the contactor state threshold value and the contactor state value are both obtained by using the differential pressure integral of the contactor, which can realize the recognition of all contactor states, especially the recognition of the contactor state in the case that the capacitor voltage slowly decreases after the contactor of the capacitive load is disconnected. In addition, the contactor state is different in the first integral period and the second integral period, that is, the first integral period and the second integral period are different time periods before and after the contactor state switches, and the contactor state threshold value uses the differential pressure integral in the first integral period before the contactor state switches, which can exclude the influence of factors such as contactor temperature and sampling error, and improve the reliability of contactor state recognition.

[0052] Referring to Figure 1 The embodiment of the present application discloses a flow chart of a contactor state recognition method, and the method comprises the following steps:

[0053] Step S101, recognizing contactor state information.

[0054] The contactor state information is the disconnection of the contactor or the closure of the contactor.

[0055] Step S102, determining a contactor state threshold value based on a differential pressure integral of the contactor in a first integral period.

[0056] The first integral period is a period before the contactor state switches.

[0057] In actual application, the differential pressure integral can be the integral of each discrete value in the integral period, or the integral of continuous values in the integral period, which is specifically determined according to actual needs, and the present application does not make any limitation here.

[0058] Step S103, determining a contactor state value based on a differential pressure integral of the contactor in a second integral period.

[0059] The second integral period is a period after the contactor state switches.

[0060] In practical application, the first integration time period and the second integration time period are adjacent time periods, that is, the first integration time period and the second integration time period have the same time boundary point, and the first integration time period and the second integration time period are different time periods before and after the switching of the contactor state.

[0061] In practical application, if the back end of the contactor is a capacitive load, when the capacitive load needs to stop working, after the contactor is disconnected, the capacitor voltage will not immediately become 0, but will slowly decrease, at this time, the voltage difference between the two ends of the contactor is still very small, if the disconnection state of the contactor is only judged by the voltage difference between the two ends of the contactor at this time, it is easy to misjudge, for example, the disconnection state threshold of the contactor is set to 20V, and it can be judged to be disconnected only after being greater than 20V, the voltage difference between the two ends of the contactor changes very slowly due to the capacitor effect, and it needs a very long time to be greater than 20V, if the voltage difference at a certain moment is randomly selected to judge, it is easy to misjudge as a closed state. Based on this, the present application adopts voltage difference integration to determine the contactor state value, since the integration value can be integrated to be very large in a short time, therefore, if the contactor is not disconnected, the integration value will be 0, if the contactor is disconnected, the integration value will continuously increase with the integration time, accordingly, it can be accurately judged whether the contactor is in a disconnected state or a closed state.

[0062] For the convenience of understanding, the present application provides the change process of the voltage between the two ends of the contactor during the working process. Referring to Figure 2 When the contactor currently meets the contactor state recognition trigger condition, which is the contactor sticking fault recognition trigger condition or the contactor disconnection state recognition trigger condition, the voltage difference waveform diagram of the contactor from closed to disconnected disclosed by the embodiment of the present application is shown in the figure, the abscissa is time t, the unit is s, the ordinate is the voltage between the two ends of the contactor U, the unit is V, the first integration time period is t1-t2, the second integration time period is t2-t3, t1-t2 is the closed state of the contactor, and the test voltage between the two ends of the contactor is △U c , ideally, △U c = 0. But in fact, the contactor has a closing resistance, and with the difference of the running time of the contactor, the temperature is also different, which further affects the closing resistance. In addition, the sampling circuit error will also affect the voltage difference between the two ends of the contactor, in summary, actually, △U c ≠ 0, as shown in Figure 2 .

[0063] The instruction is switched from closed to disconnected at t2, if the back end load of the contactor is resistive, the voltage difference waveform after the contactor is disconnected is a broken line CHI, that is, the voltage difference quickly reaches the battery voltage U s , if the back end load of the contactor is capacitive, the voltage difference waveform after the contactor is disconnected is , as curve CE.

[0064] Step S104, obtaining a contactor state recognition result based on the contactor state information and the size relationship between the contactor state value and the contactor state threshold.

[0065] In conclusion, the application discloses a contactor state recognition method, specifically, recognizing contactor state information, determining a contactor state threshold based on a pressure difference integral of the contactor in a first integral period, determining a contactor state value based on a pressure difference integral of the contactor in a second integral period, obtaining a contactor state recognition result based on the contactor state information and the size relationship between the contactor state value and the contactor state threshold. In the application, the contactor state threshold and the contactor state value are both obtained by the contactor pressure difference integral, which can realize the recognition of all contactor states, especially the recognition of the contactor state in the case of slow decline of the capacitor voltage after the contactor of the capacitive load is disconnected. In addition, the contactor state is different in the first integral period and the second integral period, that is, the first integral period and the second integral period are different time periods before and after the contactor state switches, and the contactor state threshold adopts the pressure difference integral in the first integral period before the contactor state switches, which can exclude the influence of factors such as contactor temperature and sampling error and improve the reliability of contactor state recognition.

[0066] In addition, the application provides a contactor pressure difference integral method for recognizing the contactor state, which is more reliable compared with the pure voltage pressure difference method. In addition, the contactor state recognition method disclosed by the application is flexible, which can recognize when the contactor is disconnected, recognize when the contactor is closed, and also recognize when the contactor is disconnected and closed, that is, the recognition can be realized in the whole process of the contactor working.

[0067] In actual application, the contactor state information can include not only the contactor disconnection or contactor closure, but also the contactor state recognition trigger condition, such as whether the contactor is assembled, the contactor driving instruction is closed or disconnected, etc.

[0068] For example, 1, the contactor circuit fault recognition trigger condition can include but is not limited to 1) the contactor has been assembled; 2) the contactor driving instruction is closed; 3) if there is a pre-contactor, the pre-contactor needs to be closed.

[0069] 2, the contactor sticking fault recognition trigger condition can include but is not limited to 1) the contactor has been assembled; 2) there is no high voltage at the front end and the rear end of the contactor after power-on; 3) the contactor driving instruction is disconnected; 4) if there is a pre-contactor, the pre-contactor needs to be closed.

[0070] 3. The contactor closed state recognition trigger condition can include, but is not limited to, 1) the contactor has been assembled; 2) the contactor has no open circuit fault and no sticking fault; 3) the battery voltage is greater than 100V; 4) the contactor driving instruction is open; 5) if there is a pre-contact, the pre-contact needs to be closed.

[0071] 4. The contactor open state recognition trigger condition can include, but is not limited to, 1) the contactor has been assembled; 2) the contactor has no open circuit fault and no sticking fault; 3) the battery voltage is greater than 100V; 4) the contactor driving instruction is closed; 5) if there is a pre-contact, the pre-contact needs to be closed.

[0072] It should be noted that the contactor state recognition trigger condition is different, and the contactor state threshold value determined based on the pressure difference integral of the contactor in the first integral period is also different.

[0073] Therefore, to further optimize the above embodiment, step S102 can specifically include:

[0074] When the contactor recognition trigger condition is the contactor sticking fault recognition trigger condition or the contactor open state recognition trigger condition, the contactor state threshold value is determined based on the pressure difference integral of the pressure difference between the two ends of the contactor when the contactor is closed in the first integral period.

[0075] In actual application, the contactor state threshold value is the pressure difference integral value or the pressure difference integral average value.

[0076] Therefore, the first pressure difference integral corresponding to the first integral period of the contactor can be calculated, and the first pressure difference integral is determined as the contactor state threshold value.

[0077] Or the first pressure difference integral average value corresponding to the first integral period of the contactor is calculated, and the first pressure difference integral average value is determined as the contactor state threshold value.

[0078] Specifically, 1) when the contactor state threshold value is the first pressure difference integral, if the contactor state recognition trigger condition currently met by the contactor is the contactor sticking fault recognition trigger condition or the contactor open state recognition trigger condition, the calculation formula of the contactor state threshold value is as follows:

[0079]

[0080] In the formula, U th is the contactor state threshold value, t2 is the moment when the contactor instruction is switched from closed to open (see FIG. (2), t1=t2-Δt, Δt is the threshold integral time and can be calibrated, △U c is the pressure difference between the two ends of the contactor when the contactor is closed, that is, Figure 3 The difference between the voltages of the sampling point 1 and the sampling point 2 of the contactor is shown.

[0081] Contactor state threshold value U th It can also be considered as Figure 2 The actual △U c It is not a straight line, but an irregular curve, representing the contactor state threshold value U th The graph ABCD of the contactor state threshold value U

[0082] 2) When the contactor state threshold value is the first pressure difference integral average value, if the contactor state recognition trigger condition currently met by the contactor is the contactor sticking fault recognition trigger condition or the contactor open state recognition trigger condition, the calculation formula of the contactor state threshold value is as follows:

[0083]

[0084] In the formula, The contactor state threshold value, t2 is the moment when the contactor command is switched from closing to opening (see Figure (2), t1=t2-Δt, Δt is the threshold integral time, which can be calibrated, △U c The pressure difference across the contactor when it is closed, that is, Figure 3 The difference between the voltages of sampling point 1 and sampling point 2 across the contactor.

[0085] Therefore, to further optimize the above embodiment, step S102 can specifically include:

[0086] When the contactor state recognition trigger condition currently met by the contactor is the contactor breaking fault recognition trigger condition or the contactor closed state recognition trigger condition, the contactor state threshold value is determined based on the pressure difference integral of the pressure difference across the contactor when it is opened in the first integral period.

[0087] In actual application, the first pressure difference integral corresponding to the first integral period of the contactor can be calculated, and the first pressure difference integral is determined as the contactor state threshold value.

[0088] Or the first pressure difference integral average value of the contactor in the first integral period is calculated, and the first pressure difference integral average value is determined as the contactor state threshold value.

[0089] Specifically, 1) when the contactor state threshold value is the first pressure difference integral, if the contactor state recognition trigger condition currently met by the contactor is the contactor breaking fault recognition trigger condition or the contactor closed state recognition trigger condition, the calculation formula of the contactor state threshold value is as follows:

[0090]

[0091] In the formula, U thHere, t1 is the contactor state threshold, t2 is the instant the contactor command switches from closed to open, t1 = t2 – Δt, Δt is the threshold integration time, and it can be calibrated. ΔU o This is the pressure difference between the two ends when the contactor is disconnected.

[0092] 2) When the contactor state threshold is the first differential pressure integral average value, if the contactor state identification trigger condition currently met by the contactor is the contactor open circuit fault identification trigger condition or the contactor closed state identification trigger condition, then the formula for calculating the contactor state threshold is as follows:

[0093]

[0094] In the formula, Here, t1 is the contactor state threshold, t2 is the instant the contactor command switches from open to closed, t1 = t2 – Δt, Δt is the threshold integration time, which can be calibrated, and ΔU is the contactor state threshold. o This is the pressure difference between the two ends when the contactor is disconnected.

[0095] It should be noted that different contactor state recognition trigger conditions will result in differences in the contactor state value determined based on the differential pressure integration during the second integration period. Therefore, to further optimize the above embodiment, step S103 may specifically include:

[0096] When the current contactor status recognition trigger condition is either the contactor adhesion fault recognition trigger condition or the contactor disconnection status recognition trigger condition, the contactor status value is determined based on the pressure difference integration at both ends during the second integration period when the contactor is disconnected.

[0097] In practical applications, the second differential pressure integral corresponding to the second integral period of the contactor can be calculated, and the second differential pressure integral can be determined as the contactor state value.

[0098] Alternatively, calculate the second differential pressure integral average value corresponding to the second integral period of the contactor, and determine the second differential pressure integral average value as the contactor state value.

[0099] Specifically, 1) When the contactor status value is the second differential pressure integral, if the contactor status identification trigger condition currently met by the contactor is the contactor adhesion fault identification trigger condition or the contactor open state identification trigger condition, then the formula for calculating the contactor status value is as follows:

[0100]

[0101] In the formula, ΔU is the contactor state value, t2 is the instant the contactor command switches from closed to open, t3=t2+Δt', Δt' is the integral time of the fault comparison quantity, which can be calibrated, ΔU oThe voltage difference between the two ends when the contactor is open. If only the voltage difference integral value is used for judgment, then Δt' = Δt; if the average value of the integral is used For comparison and judgment, Δt' and Δt can take different values and can be calibrated separately. The contactor state value ΔU can be understood as Figure 2 The area CDEG in FIG. 6.

[0102] 2) When the contactor state value is the second voltage difference integral average value, if the contactor currently meets the contactor state recognition trigger condition is the contactor sticking fault recognition trigger condition or the contactor open state recognition trigger condition, the calculation formula of the contactor state value is as follows:

[0103]

[0104] In the formula, ΔU is the contactor state value, t2 is the moment when the contactor command is switched from closing to opening, t3 = t2 + Δt', Δt' is the fault comparison quantity integral time, which can be calibrated, and ΔU o is the voltage difference between the two ends when the contactor is open.

[0105] To further optimize the above embodiment, step S103 can specifically include:

[0106] When the contactor currently meets the contactor state recognition trigger condition is the contactor open circuit fault recognition trigger condition or the contactor closed state recognition trigger condition, the contactor state value is determined based on the voltage difference integral of the voltage difference between the two ends when the contactor is closed in the second integral period.

[0107] In actual application, the contactor state value is the voltage difference integral value or the voltage difference integral average value.

[0108] Therefore, the second voltage difference integral corresponding to the second integral period of the contactor can be calculated, and the second voltage difference integral is determined as the contactor state value.

[0109] Alternatively, the second voltage difference integral average value corresponding to the second integral period of the contactor is calculated, and the second voltage difference integral average value is determined as the contactor state value.

[0110] Specifically, 1) when the contactor state value is the second voltage difference integral, when the contactor currently meets the contactor state recognition trigger condition is the contactor open circuit fault recognition trigger condition or the contactor closed state recognition trigger condition, the calculation formula of the contactor state value is as follows:

[0111]

[0112] Wherein, △U is the contactor state value, t2 is the moment when the contactor command is switched from opening to closing, t3=t2+△t', and △t' is the fault comparison quantity integral time, which can be calibrated, and △U c is the voltage difference at both ends of the contactor when the contactor is closed. If only the voltage difference integral value is used for judgment, then △t'=△t.

[0113] 2) When the contactor state value is the second voltage difference integral average value, when the contactor current satisfies the contactor opening fault identification trigger condition or the contactor closing state identification trigger condition, the calculation formula of the contactor state value is as follows:

[0114]

[0115] Wherein, △U is the contactor state value, t2 is the moment when the contactor command is switched from opening to closing, t3=t2+△t', and △t' is the fault comparison quantity integral time, which can be calibrated, and △U c is the voltage difference at both ends of the contactor when the contactor is closed.

[0116] To further optimize the above embodiment, refer to Figure 4 The embodiment of the application discloses a method flowchart for obtaining a contactor state identification result based on contactor state information and the size relationship between a contactor state value and a contactor state threshold, that is, step S104 can specifically include:

[0117] Step S201, determining a voltage difference theoretical value before and after the contactor action according to the contactor state information;

[0118] The value of the voltage difference theoretical value is determined according to actual needs, which is not limited in the application.

[0119] Step S202, calculating the difference between the contactor state value and the contactor state threshold;

[0120] Step S203, judging whether the difference is consistent with the voltage difference theoretical value, if yes, executing step S204, and if no, executing step S205;

[0121] Step S204, determining that the contactor state identification result is a contactor normal state;

[0122] In actual application, the contactor normal state includes a contactor normal closing and a contactor normal opening.

[0123] Specifically, if the contactor state information is contactor closed, and the contactor state threshold is less than the contactor state value, it is determined that the contactor state identification result is contactor normal closed.

[0124] If the contactor state information is contactor open, and the contactor state threshold is greater than the contactor state value, it is determined that the contactor state identification result is contactor normal open.

[0125] Step S205, determining that the contactor state identification result is contactor fault.

[0126] In actual application, the contactor fault includes: contactor sticking fault and contactor breaking fault.

[0127] Specifically, if the contactor state information is contactor closed, and the contactor state threshold is greater than the contactor state value, it is determined that the contactor state identification result is contactor sticking fault.

[0128] If the contactor state information is contactor open, and the contactor state threshold is less than the contactor state value, it is determined that the contactor state identification result is contactor breaking fault.

[0129] As can be seen from the above, in the present application, the contactor state threshold and the contactor state value are obtained by using the contactor differential pressure integral, which can realize the identification of all contactor states, especially the identification of the contactor state under the condition that the capacitive load is slowly descending after the contactor is opened. Based on the size relationship between the difference between the contactor state value and the contactor state threshold and the differential pressure theoretical value, the present application can further determine the contactor normal or contactor fault, so as to avoid false alarm and missed alarm in the medium and high voltage power distribution system, which can not only reduce the product failure rate and maintenance cost, but also increase the product core competitiveness and improve the enterprise image.

[0130] As can be seen from the above formula (1) to formula (8), the first integral time period is △t, and the second integral time period is △t', and the selection of the two integral time periods can consider the following factors:

[0131] 1) When the rear-end load of the contactor is resistive, the first integral time period and the second integral time period are both determined based on the contactor voltage sampling time interval, which can be set as T*contactor voltage sampling time interval (T can be calibrated).

[0132] 2) When the rear-end load of the contactor is capacitive, the first integral time period and the second integral time period can be determined according to the capacitive load voltage rising curve (see Figure 5 ) or the capacitive load voltage decay curve (see Figure 6 ).

[0133] For the capacitive load with faster voltage rise or decay, the contactor state recognition integral time can be set to a smaller value to reduce the software running time; for the capacitive load with slower voltage rise or decay, the contactor state recognition integral time can be set to a larger value to improve the recognition reliability.

[0134] 3) The first integral period and the second integral period are both determined based on the sleep power-off time of the electrical equipment, and generally do not exceed 95% of the sleep time, that is, the contactor state recognition and processing are completed before the sleep.

[0135] To further optimize the above embodiment, after step S104, the following steps can also be included:

[0136] The contactor state recognition result is stored.

[0137] In actual application, different contactor states can be stored in the memory by using different state flags, for example, the contactor sticking fault can be stored by using a sticking fault flag instead. When the contactor currently meets the contactor state recognition trigger condition, which is the contactor sticking fault, the state flag in the memory is first read, if the memory has stored the sticking fault flag, it means that the contactor has stuck, at this time, the corresponding fault action is directly executed; otherwise, if the memory does not store the sticking fault flag, the contactor instruction is updated, and the polarity contactor state recognition shown in the embodiment of the present application is adopted. Figure 1

[0138] As can be seen from the above, the present application has the fault storage function, the contactor state recognition result is stored before the device is powered off and shut down, and the stored state flag is read when the device is powered on and started, so that it can be known whether the state of the contactor is abnormal or not when the contactor has not been closed, and then the contactor is prevented from starting and working when the state is abnormal, so that the contactor and the electrical equipment can be better protected.

[0139] Corresponding to the above embodiment, the present application also discloses a contactor state recognition device.

[0140] Referring to Figure 7 , the structure schematic diagram of the contactor state recognition device disclosed by the embodiment of the present application, the device comprises:

[0141] The information recognition unit 301 is used for recognizing the contactor state information.

[0142] The contactor state information is the contactor disconnection or the contactor closure.

[0143] The state threshold determination unit 302 is used for determining the contactor state threshold based on the differential pressure integration of the contactor in the first integral period.

[0144] The first integral period is the period before the contactor state switching.​

[0145] In practical applications, the pressure difference integral can be: integral of each discrete value in the integral time period, or integral of continuous value in the integral time period, which is determined according to actual needs, and the present application does not limit it.

[0146] The state value determination unit 303 is configured to determine the contactor state value based on the pressure difference integral of the contactor in the second integral period.

[0147] The second integral period is a period after the contactor state is switched.

[0148] In practical applications, the first integral period and the second integral period are adjacent time periods, that is, the first integral period and the second integral period have the same time boundary point, and the first integral period and the second integral period are different time periods before and after the contactor state is switched.

[0149] In practical applications, if the back end of the contactor is a capacitive load, when the capacitive load needs to stop working, after the contactor is disconnected, the capacitor voltage will not immediately become 0, but will slowly decrease, at this time, the pressure difference between the two ends of the contactor is still very small, if the disconnection state of the contactor is only judged by the pressure difference between the two ends of the contactor at this time, it is easy to misjudge, for example, the contactor disconnection state threshold is set to 20V, and it can be judged to be disconnected only after being greater than 20V. The pressure difference between the two ends of the contactor changes very slowly due to the capacitor effect, and it takes a long time to be greater than 20V. If the pressure difference at a certain time is randomly selected to judge, it is easy to misjudge as a closed state. Based on this, the present application adopts pressure difference integral to determine the contactor state value, since the integral value can be integrated to be very large in a short time, therefore, if the contactor is not disconnected, the integral value will be 0, if the contactor is disconnected, the integral value will increase with the integral time, and accordingly, it can be accurately judged whether the contactor is in a disconnected state or a closed state.

[0150] The state recognition unit 304 is configured to obtain a contactor state recognition result based on the contactor state information, and the size relationship between the contactor state value and the contactor state threshold.

[0151] In summary, the application discloses a contactor state recognition device, specifically: recognizing contactor state information, determining a contactor state threshold value based on a differential pressure integral of the contactor in a first integral period, determining a contactor state value based on a differential pressure integral of the contactor in a second integral period, obtaining a contactor state recognition result based on the contactor state information and the size relationship between the contactor state value and the contactor state threshold value. In the application, the contactor state threshold value and the contactor state value are both obtained by using the differential pressure integral of the contactor, which can realize the recognition of all contactor states, especially the recognition of the contactor state in the case that the contactor is disconnected and the capacitor voltage slowly decreases. In addition, the contactor state is different in the first integral period and the second integral period, that is, the first integral period and the second integral period are different time periods before and after the contactor state switches, and the contactor state threshold value uses the differential pressure integral in the first integral period before the contactor state switches, which can exclude the influence of factors such as contactor temperature and sampling error, and improve the reliability of contactor state recognition.

[0152] In addition, the application provides a contactor differential pressure integral method for recognizing the contactor state, which is more reliable compared with the pure voltage differential method. In addition, the contactor state recognition method disclosed by the application is flexible, and can recognize the contactor state when the contactor is disconnected, recognize the contactor state when the contactor is closed, or recognize the contactor state when the contactor is disconnected and closed, that is, the recognition can be realized in the whole process of the contactor working.

[0153] To further optimize the above embodiment, the state threshold value determination unit 302 can be specifically used for:

[0154] When the contactor recognition trigger condition is the contactor sticking fault recognition trigger condition or the contactor disconnection state recognition trigger condition, the differential pressure integral of the differential pressure of the contactor at both ends in the first integral period is used to determine the contactor state threshold value.

[0155] To further optimize the above embodiment, the state threshold value determination unit 302 can be specifically used for:

[0156] When the contactor state recognition trigger condition currently met by the contactor is the contactor circuit breaking fault recognition trigger condition or the contactor closed state recognition trigger condition, the differential pressure integral of the differential pressure of the contactor at both ends in the first integral period is used to determine the contactor state threshold value.

[0157] In actual application, the first differential pressure integral of the contactor in the first integral period can be calculated, and the first differential pressure integral is determined as the contactor state threshold value.

[0158] To further optimize the above embodiment, the state value determination unit 303 can be specifically used for:

[0159] When the contactor state recognition trigger condition currently met by the contactor is the contactor sticking fault recognition trigger condition or the contactor open state recognition trigger condition, the contactor state value is determined based on the differential pressure integration of the two-terminal differential pressure of the contactor when the contactor is open for the second integration period.

[0160] To further optimize the above embodiment, the state value determination unit 303 can be specifically configured to:

[0161] When the contactor state recognition trigger condition currently met by the contactor is the contactor sticking fault recognition trigger condition or the contactor open state recognition trigger condition, the contactor state value is determined based on the differential pressure integration of the two-terminal differential pressure of the contactor when the contactor is open for the second integration period.

[0162] In actual applications, the second differential pressure integration corresponding to the second integration period of the contactor can be calculated, and the second differential pressure integration is determined as the contactor state value.

[0163] To further optimize the above embodiment, the state recognition unit 205 can specifically include:

[0164] The theoretical value determination sub-unit is configured to determine the differential pressure theoretical value before and after the action of the contactor according to the contactor state information.

[0165] The calculation sub-unit is configured to calculate the difference between the contactor state value and the contactor state threshold value.

[0166] The judgment sub-unit is configured to judge whether the difference is consistent with the differential pressure theoretical value.

[0167] The normal determination sub-unit is configured to determine that the contactor state recognition result is a contactor normal in the case where the judgment sub-unit judges yes.

[0168] In actual applications, the contactor normal includes a contactor normal closing and a contactor normal opening.

[0169] Therefore, the normal determination sub-unit is specifically configured to: if the contactor state information is a contactor closing and the contactor state threshold value is less than the contactor state value, determine that the contactor state recognition result is a contactor normal closing.

[0170] The normal determination sub-unit is specifically further configured to: if the contactor state information is a contactor opening and the contactor state threshold value is greater than the contactor state value, determine that the contactor state recognition result is a contactor normal opening.

[0171] The fault determination sub-unit is configured to determine that the contactor state recognition result is a contactor fault in the case where the judgment sub-unit judges no.

[0172] In practical applications, the contactor fault includes a contactor sticking fault and a contactor breaking fault.

[0173] Specifically, the fault determination subunit is specifically configured to determine that the contactor state recognition result is the contactor sticking fault if the contactor state information is contactor closing and the contactor state threshold value is greater than the contactor state value.

[0174] The fault determination subunit is specifically configured to determine that the contactor state recognition result is the contactor breaking fault if the contactor state information is contactor opening and the contactor state threshold value is less than the contactor state value.

[0175] As can be seen from the above, the contactor state threshold value and the contactor state value in the application are obtained by using a contactor differential pressure integral, so that the identification of all contactor states can be realized, especially the identification of the contactor state in the case of a slow decline in the capacitor voltage after the contactor of the capacitive load is opened. Based on the size relationship between the difference between the contactor state value and the contactor state threshold value and the differential pressure theoretical value, the application can further determine whether the contactor is normal or faulty, so that the high-voltage power distribution system does not misreport or miss report, which can not only reduce the product failure rate and maintenance cost, but also increase the core competitiveness of the product and improve the enterprise image.

[0176] It should be noted that when the back-end load of the contactor is resistive, the first integral period and the second integral period are determined based on a contactor voltage sampling time interval.

[0177] When the back-end load of the contactor is capacitive, the first integral period and the second integral period are determined according to a capacitive load voltage rising curve or a capacitive load voltage decay curve.

[0178] The first integral period and the second integral period are determined based on the sleep power-off time of the electrical equipment.

[0179] To further optimize the above embodiment, the identification device can further include:

[0180] The storage unit is configured to store the contactor state recognition result.

[0181] It should be particularly noted that the specific working principles of the components in the device embodiment are described in the corresponding part of the method embodiment, and will not be repeated here.

[0182] Finally, it should be noted that the terms "first", "second", and the like, herein do not denote any order, quantity, combination, or importance, but rather are used to distinguish one element from another, and are not intended to denote the presence of any such actual relationship or order. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0183] The various embodiments in the specification are described with progression in this order of description. Embodiments having the same or similar descriptions are referenced by the same reference numerals, and an overlapping description is not repeated.

[0184] The above description of disclosed embodiments provides enabling disclosure sufficient for one of ordinary skill in the art to practice the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A contactor state recognition method characterized by, The method comprises: identifying contactor state information; determining a contactor state threshold value based on a differential pressure integral of the contactor in a first integral period, wherein the first integral period is a pre-contactor state switching period; determining a contactor state value based on a differential pressure integral of the contactor in a second integral period, wherein the second integral period is a post-contactor state switching period; obtaining a contactor state recognition result based on the contactor state information and a size relationship between the contactor state value and the contactor state threshold value.

2. The contactor state recognition method according to claim 1, characterized by, The contactor state information is contactor opening or contactor closing.

3. The contactor state recognition method according to claim 1, characterized by, The contactor state recognition result is obtained based on the contactor state information and the size relationship between the contactor state value and the contactor state threshold value, comprising: determining a differential pressure theoretical value before and after the contactor action according to the contactor state information; calculating a difference value between the contactor state value and the contactor state threshold value; determining whether the difference value is consistent with the differential pressure theoretical value; if yes, determining that the contactor state recognition result is a contactor normal state; if no, determining that the contactor state recognition result is a contactor fault state.

4. The contactor state recognition method according to claim 3, characterized by, The determination that the contactor state recognition result is a contactor normal state comprises: if the contactor state information is contactor closing and the contactor state threshold value is less than the contactor state value, determining that the contactor state recognition result is a contactor normal closing state.

5. The contactor state recognition method according to claim 3, characterized by, The determination that the contactor state recognition result is a contactor normal state comprises: if the contactor state information is contactor opening and the contactor state threshold value is greater than the contactor state value, determining that the contactor state recognition result is a contactor normal opening state.

6. The contactor state recognition method according to claim 3, characterized by, The determination that the contactor state recognition result is a contactor fault state comprises: if the contactor state information is contactor closing and the contactor state threshold value is greater than the contactor state value, determining that the contactor state recognition result is a contactor sticking fault state.

7. The contactor state recognition method according to claim 3, characterized by, The determination that the contactor state recognition result is a contactor fault state comprises: if the contactor state information is contactor opening and the contactor state threshold value is less than the contactor state value, determining that the contactor state recognition result is a contactor breaking fault state.

8. The contactor state recognition method according to claim 1, characterized by, The contactor state threshold value is a differential pressure integral value or a differential pressure integral average value.

9. The contactor state recognition method according to claim 1, characterized by, The contactor state value is a differential pressure integral value or a differential pressure integral average value.

10. The contactor state recognition method according to claim 1, characterized by, When the back-end load of the contactor is resistive, the first integral period and the second integral period are determined based on a contactor voltage sampling time interval.

11. The contactor state recognition method according to claim 1, characterized by, When the back-end load of the contactor is capacitive, the first integral period and the second integral period are determined according to a capacitive load voltage rising curve or a capacitive load voltage decay curve.

12. The contactor state recognition method according to claim 1, characterized by, The first integral period and the second integral period are determined based on a sleep power-off time of a power-using device.

13. A contactor state recognition apparatus characterized by comprising: The method comprises: an information recognition unit configured to identify contactor state information; a state threshold value determination unit configured to determine a contactor state threshold value based on a differential pressure integral of the contactor in a first integral period, wherein the first integral period is a pre-contactor state switching period; The state value determining unit is configured to determine a contactor state value based on a differential pressure integration of the contactor in a second integration period, wherein the second integration period is a period after a contactor state switching; The state identifying unit is configured to obtain a contactor state identification result based on the contactor state information and a size relationship between the contactor state value and the contactor state threshold.

14. The contactor state recognition apparatus according to claim 13, wherein The state identifying unit comprises: The theoretical value determining sub-unit is configured to determine a differential pressure theoretical value before and after the contactor action according to the contactor state information; The calculating sub-unit is configured to calculate a difference value between the contactor state value and the contactor state threshold; The judging sub-unit is configured to judge whether the difference value is consistent with the differential pressure theoretical value; The normal determining sub-unit is configured to determine that the contactor state identification result is a contactor normal in a case that the judging sub-unit judges yes; The fault determining sub-unit is configured to determine that the contactor state identification result is a contactor fault in a case that the judging sub-unit judges no.

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