CN111289870B - Fault detection method and device for pre-charging circuit - Google Patents
Fault detection method and device for pre-charging circuit Download PDFInfo
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- 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
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R31/282—Testing of electronic circuits specially adapted for particular applications not provided for elsewhere
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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- H—ELECTRICITY
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- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
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Abstract
The invention provides a fault detection method for a pre-charging circuit, wherein the pre-charging circuit comprises a power supply, a switching device, a pre-charging resistor and a supporting capacitor, and the fault detection method for the pre-charging circuit comprises the following steps: respectively acquiring the voltage of the support capacitor and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times; and judging whether the pre-charging circuit is in fault or not based on the voltage of the supporting capacitor and the preset voltage threshold.
Description
Technical Field
The present invention relates to a method for controlling a high voltage system, and more particularly, to a method and an apparatus for detecting a fault in a precharge circuit.
Background
A conventional high voltage system, such as a power battery of an electric vehicle, requires a pre-charging circuit to solve the problem of sudden change of voltage and current, and fig. 1 is a schematic circuit diagram of the pre-charging circuit,the pre-charging circuit comprises a switching device K for controlling the on-off of the pre-charging circuit 2 A pre-charge resistor R and a support capacitor C. A support capacitor connected in parallel to two ends of the load L and a switching device K 2 Switching device K connected with pre-charging resistor R in series and controlling on-off of load circuit 1 And (4) connecting in parallel. In closing the switching device K 1 Before, the switching device K is first closed 2 The pre-charging circuit is switched on, and because of the pre-charging resistor R, the voltage at the two ends of the supporting capacitor cannot change suddenly, and the voltage at the two ends of the load cannot change suddenly, so that the function of protecting the load can be achieved; meanwhile, after the pre-charging circuit completes pre-charging, the switching device K is switched off 2 Closing the switching device K 1 Thereby, the pre-charging circuit is disconnected, the load circuit is conducted, at the moment, because the voltage at the two ends of the supporting capacitor C is equivalent to the voltage of the power supply B, larger conducting current can not be generated, and the current on the load circuit does not generate sudden change, thereby protecting the switch device K 1 And a load L, which maintains the stability of the circuit.
In the prior art, it is usually determined whether the precharge circuit completes the precharge by determining whether the voltage of the support capacitor C is equal to the voltage of the power supply B, and this determination may be performed when the precharge time reaches the expected full charge time of the support capacitor, or continuously determining whether the precharge process is completed within a period of time, but both determination methods determine whether the precharge process is completed or fails based on the fact that the precharge time is close to or exceeds the time required for complete precharge.
When other parts of the vehicle are in trouble or are restarted many times in a short time, the precharging process is repeated for several times, which may cause damage to components of the precharging circuit, such as the precharging resistor R. Therefore, it is desirable to provide a method for determining whether the precharge circuit has a fault before the completion of the precharge process, so as to protect the components in the precharge circuit.
Disclosure of Invention
In order to overcome the above-mentioned drawbacks, the present invention aims to provide a method for detecting a fault in a precharge circuit, which can determine whether the precharge circuit has a fault before the precharge time does not satisfy the time required for the precharge process, so that the precharge circuit can be timely turned off when the precharge circuit has a fault.
According to an aspect of the present invention, there is provided a precharge circuit failure detection method, the precharge circuit including a power supply, a switching device, a precharge resistor, and a support capacitor, the precharge circuit failure detection method including:
respectively acquiring the voltage of the support capacitor and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times; and
and judging whether the pre-charging circuit fails or not based on the voltage of the supporting capacitor and the preset voltage threshold.
Further, the predetermined voltage threshold is related to the target value of the support capacitor voltage for each pre-charge time.
Further, the support capacitor voltage target value is related to the power supply voltage nominal value.
Further, the supporting capacitor voltage target value is related to the power supply voltage measured value, and the acquiring further includes:
and acquiring the measured value of the power supply voltage.
Further, the plurality of pre-charging times are RC, 2RC and 5RC, where R is a resistance value of a pre-charging resistor of the pre-charging circuit, and C is a capacitance value of the supporting capacitor.
Further, the determining includes:
and judging the fault of the pre-charging circuit in response to the fact that the voltage of the supporting capacitor does not reach the preset voltage threshold corresponding to the pre-charging time.
Further, the determining further includes:
and responding to the situation that the voltage of the supporting capacitor exceeds the preset error range of the preset voltage threshold, and judging that the voltage of the supporting capacitor does not reach the preset voltage threshold corresponding to the pre-charging time.
Further, the precharge circuit fault detection method further includes:
and responding to any pre-charging time to judge the failure of the pre-charging circuit and generating an alarm signal.
Further, the precharge circuit fault detection method further includes:
and responding to all the pre-charging time to judge that the pre-charging circuit does not generate faults, and disconnecting the pre-charging circuit through the switching device to finish the pre-charging process.
According to another aspect of the present invention, there is provided a precharge circuit failure detection apparatus including a power supply, a switching device, a precharge resistor, and a support capacitor, the precharge circuit failure detection apparatus including a controller configured to:
respectively acquiring the voltage of the support capacitor and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times; and
and judging whether the pre-charging circuit fails or not based on the voltage of the supporting capacitor and the preset voltage threshold.
Further, the predetermined voltage threshold is related to the target value of the support capacitor voltage at each pre-charge time.
Further, the support capacitor voltage target value is related to the power supply voltage nominal value.
Further, the support capacitor voltage target value is related to the power supply voltage measured value, and the controller is further configured to:
and acquiring the measured value of the power supply voltage.
Further, the plurality of precharge times are RC, 2RC and 5RC.
Further, the controller is further configured to:
and judging the fault of the pre-charging circuit in response to the fact that the voltage of the supporting capacitor does not reach a preset voltage threshold value corresponding to the pre-charging time.
Further, the controller is further configured to:
and responding to the situation that the voltage of the supporting capacitor exceeds the preset error range of the voltage target value of the supporting capacitor, and judging that the voltage of the supporting capacitor does not reach the preset voltage threshold value corresponding to the pre-charging time.
Further, the controller is further configured to:
and responding to any pre-charging time to judge the failure of the pre-charging circuit and generating an alarm signal.
Further, the controller is further configured to:
and responding to all the pre-charging time to judge that the pre-charging circuit does not generate faults, and disconnecting the pre-charging circuit through the switching device to finish the pre-charging process.
Further, the controller is a vehicle controller.
According to still another aspect of the present invention, there is provided a high voltage power supply system including a precharge circuit and the precharge circuit failure detection apparatus of any one of the above.
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.
FIG. 1 is a schematic diagram of a precharge circuit according to one aspect of the present invention;
FIG. 2 is a flow chart of one embodiment depicted in accordance with an aspect of the present invention;
FIG. 3 is a flow chart of yet another embodiment depicted in accordance with an aspect of the present invention;
FIG. 4 is a flow chart of another embodiment depicted in accordance with an aspect of the present invention;
fig. 5 is a flow chart of yet another embodiment according to an aspect of the present invention.
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.
In the prior art, whether the charging process is completed or not can be judged by judging whether the voltage of the supporting capacitor is equal to the power supply voltage or not only when the pre-charging time reaches the time required by the pre-charging circuit to complete the pre-charging process, and meanwhile, if the voltage of the supporting capacitor is not equal to the power supply voltage, the possibility that the pre-charging circuit has a fault can be judged, but whether the pre-charging circuit has a fault or not can not be judged in the pre-charging process. Thus, according to one aspect of the present invention, a method of precharge circuit fault detection is provided.
Wherein, the pre-charging circuit can be illustrated by fig. 1, and the power supply B can be a power battery of an electric vehicle or other high-voltage systems; the switching device K 1 A relay, contactor or other switching element that is a load circuit; the switching device K 2 A relay, contactor or other switching element that is a pre-charge circuit; the pre-charging resistor R is a fixed resistor or an adjustable resistor on the pre-charging circuit; and the support capacitor C is connected in parallel at two ends of a port of the power supply B connected with the load.
In one embodiment, as shown in FIG. 2, the precharge circuit failure detection method 100 includes:
s110: respectively acquiring the voltage of the support capacitor C and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times;
s120: and at each pre-charging time, judging whether the pre-charging circuit has faults or not based on the voltage of the support capacitor C and a preset voltage threshold corresponding to the pre-charging time.
Switching device K of pre-charging time slave pre-charging circuit 2 And when the circuit is closed, calculation is started, and a plurality of different times for acquiring the voltage of the support capacitor and the preset voltage threshold, such as the first pre-charging time to the Nth pre-charging time, can be set according to the estimated complete pre-charging time of the pre-charging circuit. From closing switching device K 2 The method comprises the steps that timing is started, when first pre-charging time is reached, the voltage of a support capacitor C at the moment and a corresponding preset voltage threshold are obtained, whether a fault exists in a pre-charging circuit at the moment is judged according to the voltage of the support capacitor C and the preset voltage threshold, and if the fault does not exist, the next fault detection process is continuously waited; when the judgment result of the first pre-charging time is normal, namely no fault exists, the timing time is accumulated, and when the timing time reaches the second pre-charging time, the voltage of the support capacitor C at the moment and the corresponding voltage are acquiredThe voltage of the support capacitor C and the preset voltage threshold value are used for judging whether the pre-charging circuit has faults or not, and if the faults do not exist, the next fault detection process is continuously waited; repeating the fault detection process until the Nth pre-charging time is judged, and if the judgment results of all the pre-charging times are that the pre-charging circuit has no fault, finishing the pre-charging process and disconnecting the switching device K 2 To open the pre-charge circuit and close the switching device K 1 To complete the load circuit. If the judgment result of any one of the first to Nth pre-charging time indicates that the pre-charging circuit has a fault, an alarm signal is generated so that a control system of the high-voltage system can take proper control measures, such as disconnecting the pre-charging circuit and the like.
Whether the pre-charging circuit is in fault or not is judged based on the plurality of different pre-charging times by setting the plurality of different pre-charging times, so that the fault of the pre-charging circuit can be identified in advance, the pre-charging circuit device is protected in advance, and further damage is prevented.
It is understood that, preferably, the plurality of precharge times at least includes a precharge process complete time, that is, the last precharge time in the plurality of precharge times should be a time when the voltage of the support capacitor is substantially equal to the power supply voltage, and at this time, it can be determined whether the precharge process is completed and at the same time, it can be determined whether the precharge circuit at this time has a fault.
Specifically, the preset voltage threshold is related to the target value of the support capacitor voltage at each pre-charge time, i.e. whether the pre-charge process of the support capacitor is performed normally is determined by comparing the actual value of the support capacitor voltage with the target value of the support capacitor voltage.
In an embodiment, the preset voltage threshold in the method 100 for detecting a fault of a pre-charge circuit is a theoretical voltage value of the support capacitor, and based on the circuit diagram shown in fig. 1, assuming that the initial voltage of the support capacitor is 0, the target voltage value of the support capacitor may be set based on the theoretical voltage value of the support capacitor, and the theoretical voltage value of the support capacitor may be calculated based on the following formula:
wherein Uc (t) is the theoretical voltage value of the support capacitor when the pre-charging time is t, us is the voltage value of the power supply B, t is the pre-charging time, R is the resistance value of the pre-charging resistor, and C is the capacitance value of the support capacitor.
According to the preset precharge time t, theoretical values Uc (t) of the support capacitor voltages, namely preset voltage threshold values, can be obtained. From this equation, the theoretical value of the support capacitor voltage is related to the power supply voltage, which may be the nominal voltage value E of the high voltage system B, and the following preset voltage threshold values (two effective values are retained) can be obtained by substituting t with the actual time value according to the above equation (1):
when t =0.5RC, uc (t) =0.39E;
when t = RC, uc (t) =0.63E;
at t =1.5RC, uc (t) =0.78E;
uc (t) =0.86E, t =2 RC;
at t =2.5RC, uc (t) =0.92E;
at t =3RC, uc (t) =0.95E;
at t =4RC, uc (t) =0.98E;
uc (t) =0.99E when t =5 RC;
since the voltage value of the support capacitor can never be equal to the power supply voltage value according to theoretical calculation, in practical applications, it is common to judge that the voltage value of the support capacitor is approximately equal to the power supply voltage when the voltage value of the support capacitor reaches 0.98Us or 0.99Us. Therefore, an appropriate number of precharge times can be selected from the plurality of precharge times as the time at which the failure determination is finally required. For example, the plurality of precharge times may be set to 5 precharge times: 0.5RC, 2RC, 3RC, and 4RC, 5 preset voltage thresholds corresponding to the 5 precharge times may be set as: 0.39E, 0.63E, 0.86E, 0.95E, and 0.98E.
And acquiring the actually measured voltage Uc and the preset voltage threshold of the support capacitor at the moment based on each pre-charging time, and judging whether the Uc reaches the preset voltage threshold, thereby judging whether the pre-charging circuit fails.
It can be understood that, because a difference exists between the nominal value and the actual value of the power supply voltage, and the nominal value of the aged high-voltage system changes, the voltage of the actual support capacitor is difficult to fill to the nominal value of the power supply voltage.
In a preferred embodiment, the preset voltage threshold is equal to the theoretical voltage value of the support capacitor, and to improve the accuracy of the determination result, the power voltage in formula (1) is the actual voltage value of the high-voltage system, as shown in fig. 3, the method 200 for detecting the fault of the pre-charge circuit includes:
s210: respectively acquiring the voltage of the support capacitor C, the measured value of the power supply voltage and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times;
s220: and judging the fault of the pre-charging circuit in response to the fact that the voltage of the supporting capacitor does not reach the preset voltage threshold corresponding to the pre-charging time.
It is understood that the actual voltage value can be obtained by actually detecting the power voltage through some detection device or detection means, i.e. an actual measurement value commonly found in the electrical field.
Substituting t with the actual time value according to the above equation (1) can obtain the following preset voltage threshold (two-bit effective value is retained):
at t =0.5RC, uc (t) =0.39Us;
when t = RC, uc (t) =0.63Us;
at t =1.5RC, uc (t) =0.78Us;
at t =2RC, uc (t) =0.86Us;
at t =2.5RC, uc (t) =0.92Us;
at t =3RC, uc (t) =0.95Us;
at t =4RC, uc (t) =0.98Us;
at t =5RC, uc (t) =0.99Us;
since the voltage value of the support capacitor can never be equal to the power supply voltage value in accordance with theoretical calculation, in practical applications, it is common to judge that the voltage value of the support capacitor is substantially equal to the power supply voltage when the voltage value of the support capacitor reaches 0.98Us or 0.99Us. Thus, the plurality of precharge times can be set to 4 precharge times: RC, 2RC, 3RC, and 4RC, 4 preset voltage thresholds corresponding to the 4 precharge times may be set as: 0.63Us, 0.86Us, 0.95Us and 0.98Us.
And then, based on each pre-charging time, after the actual voltage Uc of the support capacitor and the power supply voltage Us at the moment are obtained, calculating a preset voltage threshold value at the moment according to Us, and judging whether the Uc reaches the preset voltage threshold value based on the Uc and the preset voltage threshold value, thereby judging whether the pre-charging circuit fails.
It can be understood that the voltage of the actual support capacitor is difficult to reach the ideal state because there may be more or less errors between the nominal values and the actual values of the support capacitor and the pre-charge resistor, and there may also be errors between the actual values and the actual values. Therefore, the "reached" in step S220 may be regarded as an ideal state when the voltage value of the support capacitor is within the allowable error range of the preset voltage threshold, and the support capacitor voltage is approximately equal to the target value of the support capacitor voltage by default. And correspondingly, responding to the fact that the voltage of the supporting capacitor exceeds the preset error range of the preset voltage threshold, and judging that the voltage of the supporting capacitor does not reach the ideal state, namely does not reach the preset voltage threshold corresponding to the pre-charging time.
In a preferred embodiment, as shown in FIG. 4, a precharge circuit fault detection method 300 includes:
s210: respectively acquiring the voltage of the support capacitor C, a power supply voltage measured value and a preset voltage threshold value corresponding to the pre-charging time at a plurality of different pre-charging times;
s320: and judging the fault of the pre-charging circuit in response to the fact that the voltage of the supporting capacitor exceeds the preset error range of the preset voltage threshold value.
For example, assume that the plurality of precharge times are set to 3 precharge times: RC, 2RC and 5RC, 3 preset voltage thresholds corresponding to the 3 precharge times can be set as: 0.63Us, 0.86Us and 0.99Us. The preset error ranges can be set based on the accuracy requirements of the preset voltage thresholds, and if the error ranges of the first preset voltage threshold 0.63Us and the second preset voltage threshold 0.86Us are set to ± 10%, and the error range of the third preset voltage threshold 0.99Us is set to ± 1%, the specific determination process is as follows:
during the first pre-charge time RC, the step S320 specifically includes: when the voltage of the supporting capacitor is less than 0.63us 90% or more than 0.63us 110%, judging that the pre-charging circuit has a fault, generating an alarm signal, and otherwise, continuing to wait for a second fault detection process;
in the second precharge time 2RC, step S320 specifically includes: when the voltage of the supporting capacitor is less than 0.86us 90% or more than 0.86us 110%, judging that the pre-charging circuit has a fault, generating an alarm signal, and otherwise, continuing to wait for a third fault detection process;
when the third precharge time is 5RC, step S320 specifically includes: when the voltage of the supporting capacitor is less than 0.99Us 99% or more than 0.99Us 101%, judging that the pre-charging circuit is in fault, and generating an alarm signal; otherwise, it is judged that the precharge process is completed, the switching device K2 is opened to open the precharge circuit, and the switching device K1 is closed to turn on the load circuit.
It can be understood that the preset error range can be set according to the parameter error of the component, the parameter obtaining error and other factors.
It is to be understood that the preset threshold is set based on the voltage target value of the supporting capacitor, and actually the preset voltage threshold may also be a threshold of a difference value between the power supply voltage and the voltage of the supporting capacitor, in an embodiment, as shown in fig. 5, the method 400 for detecting a malfunction of a precharge circuit includes:
s210: respectively acquiring the voltage of the support capacitor C, the measured value of the power supply voltage and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times;
s420: calculating a voltage difference value between the power supply voltage and the support capacitor voltage;
s430: and judging the fault of the pre-charging circuit in response to the fact that the voltage difference value exceeds a preset error range of the preset voltage threshold value.
In this embodiment, the theoretical value of the voltage difference is Us-Uc (t), where Uc (t) can be calculated based on equation (1), i.e.:
when t =0.5RC, us-Uc (t) =0.61Us;
when t = RC, us-Uc (t) =0.37Us;
when t =1.5RC, us-Uc (t) =0.22Us;
Us-Uc (t) =0.14Us when t =2 RC;
when t =2.5RC, us-Uc (t) =0.08Us;
when t =3RC, us-Uc (t) =0.05Us;
at t =4RC, us-Uc (t) =0.02Us;
at t =5RC, us-Uc (t) =0.01Us;
a plurality of precharge times may be selected from the plurality of precharge times as the "plurality of precharge times", and the preset voltage threshold corresponding to the plurality of precharge times may be set accordingly based on the calculation result. For example, assume that the plurality of precharge times is 5 precharge times: 0.5RC, 1.5RC, 2RC, and 4RC, 5 preset voltage thresholds corresponding to the 5 precharge times may be set as: 0.61Us, 0.37Us, 0.22Us, 0.14Us and 0.02Us.
In contrast, the preset error ranges may be set based on the accuracy requirements of the plurality of preset voltage thresholds, for example, if the error ranges of the first preset voltage threshold 0.61Us and the second preset voltage threshold 0.37Us are set to ± 10%, the error ranges of the third preset voltage threshold 0.22Us and the fourth preset voltage threshold 0.14Us are set to 5%, and the error range of the fifth preset voltage threshold is set to ± 1%, the specific determination process is as follows:
when the first pre-charge time is 0.5RC, the step S430 specifically includes: when the voltage difference value between the power supply voltage and the supporting capacitor is less than 0.61us 90% or more than 0.61us 110%, judging that the pre-charging circuit has a fault, generating an alarm signal, and otherwise, continuously waiting for a second fault detection process;
in the second pre-charge time RC, the step S430 specifically includes: when the voltage difference value between the power supply voltage and the supporting capacitor is less than 0.37us 90% or more than 0.37us 110%, judging that the pre-charging circuit has a fault, generating an alarm signal, and otherwise, continuously waiting for a third fault detection process;
when the third pre-charging time is 1.5RC, step S430 specifically includes: when the voltage difference value between the power supply voltage and the supporting capacitor is less than 0.22us 95% or more than 0.22us 105%, judging that the pre-charging circuit has a fault, generating an alarm signal, and otherwise, continuously waiting for a fourth fault detection process;
in the fourth precharge time 2RC, step S430 specifically includes: when the voltage difference value between the power supply voltage and the supporting capacitor is less than 0.14us 95% or more than 0.14us 105%, judging that the pre-charging circuit has a fault, generating an alarm signal, and otherwise, continuously waiting for a fifth fault detection process;
in the fifth precharge time 5RC, step S320 specifically includes: when the voltage difference value between the power supply voltage and the supporting capacitor is less than 0.02us 99% or more than 0.02us 101%, judging that the pre-charging circuit has a fault, and generating an alarm signal; otherwise, judging that the pre-charging process is finished, and disconnecting the switching device K 2 To open the pre-charge circuit and close the switching device K 1 To complete the load circuit.
According to another aspect of the present invention, a pre-charging circuit fault detection device is provided, the pre-charging circuit can be illustrated by fig. 1, and the power supply B can be a power battery or other high-voltage system of an electric vehicle; the switching device K 1 A relay, contactor or other switching element that is a load circuit; the switching device K 2 A relay, contactor, or other switching element that is a pre-charge circuit; the pre-charging resistor R is a fixed resistor or an adjustable resistor on the pre-charging circuit; and the support capacitor C is connected in parallel at two ends of a port of the power supply B connected with the load. The precharge circuit failure detection apparatus includes a controller.
The controller respectively acquires the voltage of the support capacitor and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times, and judges whether the pre-charging circuit fails or not based on the voltage of the support capacitor and the preset voltage threshold.
It can be understood that the voltage value of the support capacitor can be obtained by obtaining or adding a voltage detection module of the support capacitor from a parameter sampling module inside the high-voltage system to obtain the voltage of the support capacitor.
Specifically, the preset voltage threshold may be a voltage target value of the support capacitor, that is, the determination may be: and when the voltage value of the supporting capacitor reaches the voltage target value of the supporting capacitor, judging that the pre-charging circuit has no fault, otherwise, judging that the pre-charging circuit has the fault.
Further, the voltage target value of the supporting capacitor may be a theoretical voltage value of the supporting capacitor, and equation (1) may be calculated based on the voltage of the supporting capacitor:
at t =0.5RC, uc (t) =0.39Us;
when t = RC, uc (t) =0.63Us;
at t =1.5RC, uc (t) =0.78Us;
at t =2RC, uc (t) =0.86Us;
at t =2.5RC, uc (t) =0.92Us;
at t =3RC, uc (t) =0.95Us;
at t =4RC, uc (t) =0.98Us;
at t =5RC, uc (t) =0.99Us;
therefore, the pre-charge times and the voltage target values of the supporting capacitors can be selected from the pre-charge times and the voltage theoretical values of the corresponding supporting capacitors based on a certain rule.
Preferably, the plurality of precharge times includes at least a precharge process complete time, i.e. the last precharge time in the plurality of precharge times should be a time when the support capacitor is substantially equal to the power supply voltage, such as 4RC or 5RC, and at this time, it can be determined whether the precharge process is completed and at the same time, it can be determined whether the precharge circuit is malfunctioning.
It is understood that Us in the theoretical value of the voltage of the support capacitor can be substituted with a nominal value or an actual value of the supply voltage. When the measured value of the power voltage is used for substitution, the controller needs to simultaneously obtain the measured value of the power voltage at each pre-charging time. The actual measurement value of the power voltage can be obtained from a parameter sampling module inside the high voltage system or obtained by adding a power voltage detection module.
It can be understood that, since there may be more or less errors between the nominal values and the actual values of the support capacitor and the pre-charge resistor, and there is also an error between the actual value and the actual value of the power voltage, the voltage of the support capacitor in practice is difficult to reach the ideal state, i.e. difficult to be equal to the voltage target value of the support capacitor, and therefore, when the voltage value of the support capacitor is within the allowable error range of the preset voltage threshold, it is considered that the voltage of the support capacitor is substantially equal to the voltage target value of the support capacitor. And correspondingly, responding to the fact that the voltage of the supporting capacitor exceeds the preset error range of the preset voltage threshold, and judging that the voltage of the supporting capacitor does not reach the preset voltage threshold corresponding to the pre-charging time.
For example, assume that the plurality of precharge times are set to 3 precharge times: RC, 2RC and 5RC, 3 preset voltage thresholds corresponding to the 3 precharge times can be set as: 0.63Us, 0.86Us and 0.99Us. The preset error ranges can be set based on the accuracy requirements of the preset voltage thresholds, and if the error ranges of the first preset voltage threshold 0.63Us and the second preset voltage threshold 0.86Us are set to ± 10%, and the error range of the third preset voltage threshold 0.99Us is set to ± 1%, the specific determination process is as follows:
when the voltage of the supporting capacitor is smaller than 0.63us 90% or larger than 0.63us 110% during the first pre-charging time RC, the controller judges that the pre-charging circuit has a fault and generates an alarm signal, otherwise, the controller continues to wait for a second fault detection process;
when the voltage of the supporting capacitor is less than 0.86us 90% or more than 0.86us 110% during the second precharge time 2RC, the controller judges that the precharge circuit has a fault and generates an alarm signal, otherwise, the controller continues to wait for a third fault detection process;
when the voltage of the supporting capacitor is less than 0.99us 99% or more than 0.99us 101% during the third pre-charging time 5RC, the controller judges that the pre-charging circuit is in fault and generates an alarm signal; otherwise, it is judged that the precharge process is completed, a control signal is generated to open the switching device K2 to open the precharge circuit, and to close the switching device K1 to turn on the load circuit.
Alternatively, the preset voltage threshold may also be a theoretical value of a voltage difference between the power supply voltage and the support capacitor voltage, and the specific precharge time and the theoretical value of the voltage difference are as follows:
when t =0.5RC, us-Uc (t) =0.61Us;
when t = RC, us-Uc (t) =0.37Us;
when t =1.5RC, us-Uc (t) =0.22Us;
when t =2RC, us-Uc (t) =0.14Us;
when t =2.5RC, us-Uc (t) =0.08Us;
when t =3RC, us-Uc (t) =0.05Us;
at t =4RC, us-Uc (t) =0.02Us;
Us-Uc (t) =0.01Us when t =5 RC;
it is understood that the pre-charging times can be selected from the above examples, and other suitable times can be selected to calculate the theoretical value of the voltage difference based on the formula (1).
It can be understood that, when the preset voltage threshold is a theoretical value of a voltage difference between the power voltage and the voltage of the support capacitor, the controller calculates the preset voltage threshold at each pre-charging time according to the measured power voltage, and then determines whether the pre-charging circuit is faulty based on the voltage difference between the measured power voltage and the voltage of the support capacitor and the preset voltage threshold.
It will be appreciated that the controller determines a malfunction of the pre-charge circuit in response to an error in the voltage difference exceeding a predetermined voltage threshold at any one pre-charge time, and generates an alarm signal which may be used to trigger a protection mechanism of the pre-charge circuit, such as opening the switching device K 2 To turn off the precharge circuit; in response to the fact that the voltage difference value is within the error range of the preset voltage threshold value during all the pre-charging time, the controller judges that the pre-charging circuit is completed and triggers the switching device K 2 Disconnecting and switching device K 1 Closed, thereby opening the precharge circuit and conducting the load circuit.
It will be appreciated that the controller may be a vehicle controller or a dedicated fault detection controller or other controller that may be used for fault detection of the pre-charge circuit.
According to yet another aspect of the present invention, there is provided a high voltage power supply system comprising a precharge circuit and a precharge circuit failure detection apparatus as described in any one of the above embodiments.
While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein or not shown and described herein, as would be understood by one skilled in the art.
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.
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 is provided to enable any person skilled in the art to practice the various aspects described herein. It is to be understood that the scope of the invention is to be defined by the appended claims and not by the specific constructions and components of the embodiments illustrated above. Those skilled in the art can make various changes and modifications to the embodiments within the spirit and scope of the present invention, and these changes and modifications also fall within the scope of the present invention.
Claims (20)
1. A precharge circuit failure detection method, the precharge circuit including a power supply, a switching device, a precharge resistor, and a support capacitor, the precharge circuit failure detection method comprising:
respectively acquiring the voltage of the support capacitor and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times which are sequentially accumulated and are set according to the estimated complete pre-charging time of the pre-charging circuit; and
and judging whether the pre-charging circuit fails or not based on the voltage of the supporting capacitor and the preset voltage threshold.
2. The method of claim 1, wherein the predetermined voltage threshold is related to a target value of the support capacitor voltage for each precharge time.
3. The precharge circuit fault detection method as claimed in claim 2, wherein said support capacitor voltage target value is related to said supply voltage nominal value.
4. The method of claim 2, wherein the target support capacitor voltage value is related to the measured power supply voltage value, and the obtaining further comprises:
and acquiring the measured value of the power supply voltage.
5. The pre-charge circuit fault detection method of claim 1, wherein the plurality of pre-charge times are RC, 2RC and 5RC, where R is a resistance value of a pre-charge resistor of the pre-charge circuit and C is a capacitance value of the support capacitor.
6. The precharge circuit fault detection method as claimed in claim 1, wherein said determining comprises:
and judging the fault of the pre-charging circuit in response to the fact that the voltage of the supporting capacitor does not reach the preset voltage threshold corresponding to the pre-charging time.
7. The precharge circuit fault detection method as claimed in claim 6, wherein said determining further comprises:
and responding to the situation that the voltage of the supporting capacitor exceeds the preset error range of the preset voltage threshold, and judging that the voltage of the supporting capacitor does not reach the preset voltage threshold corresponding to the pre-charging time.
8. The precharge circuit failure detection method as claimed in claim 1, further comprising:
and responding to any pre-charging time to judge the failure of the pre-charging circuit and generating an alarm signal.
9. The precharge circuit fault detection method as claimed in claim 1, further comprising:
and responding to all the pre-charging time to judge that the pre-charging circuit does not generate faults, and disconnecting the pre-charging circuit through the switching device to finish the pre-charging process.
10. A pre-charge circuit fault detection apparatus, the pre-charge circuit comprising a power supply, a switching device, a pre-charge resistor, and a support capacitor, the pre-charge circuit fault detection apparatus comprising a controller configured to:
respectively acquiring the voltage of the support capacitor and a preset voltage threshold corresponding to the pre-charging time at a plurality of different pre-charging times which are sequentially accumulated and are set according to the estimated complete pre-charging time of the pre-charging circuit; and
and judging whether the pre-charging circuit fails or not based on the voltage of the supporting capacitor and the preset voltage threshold.
11. The precharge circuit fault detection device as claimed in claim 10, wherein said predetermined voltage threshold is related to a support capacitor voltage target value for each precharge time.
12. The precharge circuit fault detection device as claimed in claim 11, wherein said support capacitor voltage target value is related to said supply voltage nominal value.
13. The precharge circuit fault detection device as claimed in claim 11, wherein the support capacitor voltage target value is related to the power supply voltage measured value, the controller is further configured to:
and acquiring the measured value of the power supply voltage.
14. The precharge circuit fault detection device as claimed in claim 10, wherein the plurality of precharge times are RC, 2RC and 5RC.
15. The precharge circuit fault detection device as claimed in claim 10, wherein the controller is further configured to:
and judging the fault of the pre-charging circuit in response to the fact that the voltage of the supporting capacitor does not reach the preset voltage threshold corresponding to the pre-charging time.
16. The precharge circuit fault detection device as claimed in claim 15, wherein said controller is further configured to:
and responding to the situation that the voltage of the supporting capacitor exceeds the preset error range of the voltage target value of the supporting capacitor, and judging that the voltage of the supporting capacitor does not reach the preset voltage threshold value corresponding to the pre-charging time.
17. The precharge circuit fault detection device as claimed in claim 10, wherein said controller is further configured to:
and responding to any pre-charging time to judge the failure of the pre-charging circuit and generating an alarm signal.
18. The precharge circuit failure detection apparatus as recited in claim 10, wherein the controller is further configured to:
and responding to all the pre-charging time to judge that the pre-charging circuit does not generate faults, and disconnecting the pre-charging circuit through the switching device to finish the pre-charging process.
19. The precharge circuit fault detection device as claimed in claim 10, wherein said controller is a vehicle controller.
20. A high voltage power supply system comprising a precharge circuit and a precharge circuit failure detection apparatus as claimed in any one of claims 10 to 19.
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| CN201811484887.0A CN111289870B (en) | 2018-12-06 | 2018-12-06 | Fault detection method and device for pre-charging circuit |
| PCT/CN2019/116148 WO2020114187A1 (en) | 2018-12-06 | 2019-11-07 | Pre-charging circuit fault detection method and apparatus |
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| CN112462316B (en) * | 2021-01-28 | 2021-05-11 | 广汽丰田汽车有限公司 | Pre-charge reference voltage calibration method, detection and control method, medium and system |
| CN115528898A (en) | 2021-06-25 | 2022-12-27 | 台达电子企业管理（上海）有限公司 | Pre-charging system and method |
| CN114545064B (en) * | 2022-02-23 | 2024-10-11 | 浙江诺诺网络科技有限公司 | Equipment fault monitoring method, device and system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103580458A (en) * | 2012-07-26 | 2014-02-12 | 珠海格力电器股份有限公司 | Control method and control device of capacitor charging circuit and capacitor charging circuit |
| CN103825458A (en) * | 2014-03-21 | 2014-05-28 | 大陆汽车投资（上海）有限公司 | Direct current-direct current converter and pre-charge method |
| CN106680622A (en) * | 2016-12-08 | 2017-05-17 | 国网北京市电力公司 | Charging pile detection method and device, and charging pile detection circuit |
| CN107482741A (en) * | 2016-06-13 | 2017-12-15 | 宝沃汽车（中国）有限公司 | Charge control method and system |
Family Cites Families (1)
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| JP5274046B2 (en) * | 2008-02-21 | 2013-08-28 | 三洋電機株式会社 | Power supply for vehicle |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103580458A (en) * | 2012-07-26 | 2014-02-12 | 珠海格力电器股份有限公司 | Control method and control device of capacitor charging circuit and capacitor charging circuit |
| CN103825458A (en) * | 2014-03-21 | 2014-05-28 | 大陆汽车投资（上海）有限公司 | Direct current-direct current converter and pre-charge method |
| CN107482741A (en) * | 2016-06-13 | 2017-12-15 | 宝沃汽车（中国）有限公司 | Charge control method and system |
| CN106680622A (en) * | 2016-12-08 | 2017-05-17 | 国网北京市电力公司 | Charging pile detection method and device, and charging pile detection circuit |
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