CN116298866A - Detection method for ground fault of motor controller output - Google Patents
Detection method for ground fault of motor controller output Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G—PHYSICS
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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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Abstract
The embodiment of the invention provides a detection method for a grounding fault of an output side of a motor controller, and belongs to the technical field of grounding of motor controllers. The method comprises the steps of collecting the current zero vector and capacitor voltage of a motor controller; and detecting the ground fault of the output end of the motor controller according to the capacitance voltage of the motor controller and the current zero vector type. According to the invention, the current zero vector and the capacitor voltage of the motor controller are obtained, the grounding state of the motor controller is determined according to the class of the current zero vector of the motor controller, and then the grounding fault of the output side of the motor controller can be rapidly detected and diagnosed by combining the magnitude of the capacitor voltage of the current motor controller; meanwhile, after the ground fault of the output side of the motor controller is detected, the output is blocked quickly, abnormal charge and discharge of the ground capacitor and the ground capacitor loop for a long time are avoided, the safety of the whole vehicle is improved, and further increase of loss is avoided.
Description
Technical Field
The invention relates to the technical field of motor controller grounding, in particular to a detection method for a motor controller output-side grounding fault.
Background
The insulation fault between the high-voltage system of the new energy automobile and the ground of the automobile body is a common fault existence mode, for example, the reasons such as battery leakage, abnormal insulation of a motor winding to the ground of the automobile body, broken skin insulation layer damage of a cable and the like can possibly cause the ground fault of a high-voltage loop to the ground of the automobile body, and serious consequences such as equipment damage, personal safety and the like can be caused by the faults. Therefore, the insulation detector is an important device for new energy automobile standard.
At present, an insulation detector generally adopts an alternating current injection method or a bridge method, and the detection time is basically about 10 seconds. For the high voltage dc side, this detection time may meet the protection requirement, but for the high voltage ac side, a detection time of tens of seconds may not be effectively protected. For example, when the motor cable breaks the skin and is lapped to the car body during the running of the car, the motor controller introduces the output PWM voltage to the car body ground, at this time, the car body ground is connected with high voltage and is switched between high voltage positive and high voltage negative rapidly, in general, in order to solve the problem of EMI, an on-board electronic device is connected with a grounding capacitor between a high voltage bus and the car body ground, an abnormal high-frequency current flows through a grounding capacitance loop under the condition, if the impedance of the capacitance loop is small, the high-frequency current is large, enough heat is accumulated in a short time, the capacitance is damaged, the loop cable is burnt out, and even a fire is caused, and the conventional insulation detector cannot meet the detection protection of the fault.
The inventor of the application finds that in the process of realizing the invention, the scheme in the prior art has the defect that the loss is increased because the insulation fault of the high-voltage alternating-current side of the new energy automobile cannot be timely and effectively detected.
Disclosure of Invention
The embodiment of the invention aims to provide a method for detecting a ground fault at the output side of a motor controller, which has the function of timely and effectively detecting the insulation fault at the high-voltage alternating-current side of a new energy automobile.
In order to achieve the above object, an embodiment of the present invention provides a method for detecting a ground fault at an output side of a motor controller, including:
collecting the current zero vector and the capacitor voltage of a motor controller;
and detecting the ground fault of the output end of the motor controller according to the capacitance voltage of the motor controller and the current zero vector type.
Optionally, detecting the ground fault at the output side of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the class of the zero vector includes:
judging whether the current zero vector is V0 or not;
under the condition that the current zero vector is V0, judging whether the capacitance voltage of the motor controller is larger than or equal to a first preset voltage;
under the condition that the capacitance voltage of the motor controller is larger than or equal to a first preset voltage, judging that the output side of the motor controller has a ground fault;
and under the condition that the capacitance voltage of the motor controller is smaller than a first preset voltage, judging that the output side of the motor controller is grounded normally.
Optionally, detecting the ground fault at the output side of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the class of the zero vector further includes:
judging whether the current zero vector is V7 or not under the condition that the current zero vector is not V0;
under the condition that the current zero vector is V7, judging whether the capacitance voltage of the motor controller is smaller than or equal to a second preset voltage;
under the condition that the capacitance voltage of the motor controller is smaller than or equal to a second preset voltage, judging that the output side of the motor controller has a ground fault;
and under the condition that the capacitance voltage of the motor controller is larger than a second preset voltage, judging that the output side of the motor controller is grounded normally.
Optionally, the sum of the first preset voltage and the second preset voltage is equal to a bus voltage.
Optionally, detecting the ground fault at the output end of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the current zero vector class includes:
presetting a detection judging period;
initializing the value of a counter and sampling time to be 0;
judging whether the current zero vector is V0 or not;
judging whether the capacitance voltage of the motor controller is bus voltage or not under the condition that the current zero vector is V0;
under the condition that the capacitance voltage of the motor controller is judged to be the bus voltage, calculating the numerical value of the current moment of the counter according to a formula (1),
σ i ＝σ i-1 +1， (1)
wherein sigma i Sigma, which is the value of the current moment of the counter i-1 I is an integer number for the value of the last moment of the counter.
Optionally, detecting the ground fault at the output end of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the current zero vector class further includes:
judging whether the current zero vector is V7 or not under the condition that the current zero vector is not V0;
under the condition that the current zero vector is V7, judging whether the capacitance voltage of the motor controller is 0 or not;
and under the condition that the capacitance voltage of the motor controller is judged to be 0, calculating the value of the current moment of the counter according to the formula (1).
Optionally, detecting the ground fault at the output end of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the current zero vector class further includes:
judging whether the sampling time is greater than or equal to the detection judging period;
under the condition that the sampling time is larger than or equal to the detection judging period, the sampling period is cleared, and whether the value of the current moment of the counter is larger than or equal to a preset threshold value is judged;
under the condition that the value of the current moment of the counter is larger than or equal to a preset threshold value, judging that the output side of the motor controller has a ground fault;
under the condition that the value of the current moment of the counter is smaller than a preset threshold value, the output side of the motor controller is judged to be grounded normally;
and returning to collect the current zero vector and the capacitor voltage of the motor controller under the condition that the sampling time is smaller than the detection judging period.
Optionally, detecting the ground fault at the output end of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the current zero vector class includes:
initializing the value of a counter to 0;
judging whether the current zero vector is V0 or not;
judging whether the capacitance voltage of the motor controller is bus voltage or not under the condition that the current zero vector is V0;
under the condition that the capacitance voltage of the motor controller is judged to be the bus voltage, the value of the counter is increased by one;
and under the condition that the capacitance voltage of the motor controller is judged not to be the bus voltage, the value of the counter is reduced by one.
Optionally, detecting the ground fault at the output end of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the current zero vector class further includes:
judging whether the current zero vector is V7 or not under the condition that the current zero vector is not V0;
under the condition that the current zero vector is V7, judging whether the capacitance voltage of the motor controller is 0 or not;
under the condition that the capacitance voltage of the motor controller is judged to be 0, the value of the counter is increased by one;
and under the condition that the capacitance voltage of the motor controller is judged to be not 0, the value of the counter is reduced by one.
Optionally, detecting the ground fault at the output end of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the current zero vector class further includes:
judging whether the numerical value of the counter is larger than or equal to a preset threshold value;
under the condition that the numerical value of the counter is larger than or equal to a preset threshold value, judging that the output side of the motor controller has a ground fault;
and under the condition that the numerical value of the counter is smaller than a preset threshold value, judging that the output side of the motor controller is grounded normally.
According to the technical scheme, the detection method of the grounding fault of the motor controller output side is characterized in that the current zero vector and the capacitor voltage of the motor controller are obtained, the grounding state of the motor controller is determined according to the type of the current zero vector of the motor controller, and then the grounding fault of the motor controller output side can be rapidly detected and diagnosed by combining the magnitude of the capacitor voltage of the current motor controller; meanwhile, after the ground fault of the output side of the motor controller is detected, the output is blocked quickly, abnormal charge and discharge of the ground capacitor and the ground capacitor loop for a long time are avoided, the safety of the whole vehicle is improved, and further increase of loss is avoided.
Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain, without limitation, the embodiments of the invention. In the drawings:
FIG. 1 is a flow chart of a method of detecting a ground fault at an output side of a motor controller according to one embodiment of the invention;
FIG. 2 is a flow chart of a ground fault diagnosis in a method of detecting a ground fault at an output side of a motor controller according to one embodiment of the present invention;
FIG. 3 is a flow chart of a ground fault diagnosis in a method of detecting a ground fault at an output side of a motor controller according to one embodiment of the present invention;
FIG. 4 is a flow chart of a ground fault diagnosis in a method of detecting a ground fault at an output side of a motor controller according to one embodiment of the present invention;
fig. 5 is a flowchart of acquiring a first preset voltage and a second preset voltage in a method for detecting a ground fault at an output side of a motor controller according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a motor controller output side ground fault detection method according to one embodiment of the present invention with zero vector V0;
FIG. 7 is a schematic diagram of a zero vector V7 in a method of detecting a ground fault at the output of a motor controller according to one embodiment of the invention;
fig. 8 is a timing diagram illustrating the detection of a ground fault by a motor controller in a method for detecting a ground fault at the output side of the motor controller according to one embodiment of the present invention.
Detailed Description
The following describes the detailed implementation of the embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
Fig. 1 is a flowchart of a method of detecting a ground fault at an output side of a motor controller according to one embodiment of the present invention. In fig. 1, the detection method may include:
in step S10, the current zero vector and the capacitor voltage of the motor controller are acquired. Wherein, if the motor controller adopts Continuous Pulse Width Modulation (CPWM), zero vectors V0 and V7 exist simultaneously in each switching period; if Discontinuous Pulse Width Modulation (DPWM) is used, either a zero vector V0 or a zero vector V7 may be used for each switching period. Specifically, the PWM outputs a zero vector V0, namely switching devices of three upper bridge arms of the motor controller are all turned off, and switching devices of three lower bridge arms are all turned on; similarly, the PWM outputs a zero vector V7, that is, the switching devices of the three upper bridge arms are all turned on and the switching devices of the three lower bridge arms are all turned off. The capacitor voltage of the motor controller is the voltage of the grounding capacitor, and if the output side of the motor controller fails to be grounded, the voltage of the grounding capacitor is abnormal.
In step S11, a ground fault is detected at the output of the motor controller according to the magnitude of the capacitor voltage of the motor controller and the type of the current zero vector. According to the type of the zero vector and the magnitude of the ground capacitor voltage under the zero vector, whether the output side of the motor controller has a ground fault or not can be determined.
In step S10 to step S11, the zero vector of the motor controller is first monitored and acquired to determine the zero vector class of the motor controller in the current state. Meanwhile, according to the class of zero vectors, the magnitude of the ground capacitor voltage is combined, and whether the output side of the motor controller has a ground fault can be judged.
The insulation detection of the traditional motor controller generally adopts an alternating current injection method or a bridge method through an insulation detector, but the detection time of the method cannot effectively protect the high-voltage alternating current side, and further the loss is increased. In the embodiment of the invention, the current zero vector and the capacitor voltage of the motor controller are detected and acquired, so that the ground fault at the output end of the motor controller can be rapidly detected and diagnosed, abnormal charge and discharge of the ground capacitor and the capacitor loop for a long time are avoided, the safety of the whole vehicle is improved, and further expansion of loss is avoided.
In this embodiment of the present invention, in order to determine whether there is a ground fault on the ac side of the motor controller, it is also necessary to determine the zero vector and the capacitor voltage of the motor controller, and the specific steps may be as shown in fig. 2. Specifically, in fig. 2, the detection method may further include:
in step S20, it is determined whether or not the current zero vector is V0. The zero vector V0 indicates that the switching devices of the three upper bridge arms of the motor controller are all turned off, and the switching devices of the three lower bridge arms are all turned on. If the upper arm switch on and the lower arm switch off are denoted as 1 and the upper arm switch off and the lower arm switch on are denoted as 0, V0 may be denoted as (000), specifically, may be as shown in fig. 6.
In step S21, in the case where it is determined that the current zero vector is V0, it is determined whether the capacitance voltage of the motor controller is greater than or equal to the first preset voltage. If the zero vector is V0, it indicates that the switching devices of the three upper bridge arms of the motor controller are all turned off, and the switching devices of the three lower bridge arms are all turned on, that is, S1, S3, S5 are all turned off, S2, S4, S6 are all turned on, and at the same time, the three phase lines of the ac output side are simultaneously connected to the negative bus N.
In step S22, in the case where it is determined that the capacitance voltage of the motor controller is greater than or equal to the first preset voltage, it is determined that the ground fault occurs on the output side of the motor controller. If any phase is grounded, the negative bus N and the ground are at equal potential, i.e., the voltage u1=upn of the capacitor C1. In practical situations, a threshold voltage Uth1 (a first preset voltage) may be set, and when the voltage of the capacitor C1 is greater than or equal to the threshold voltage, the voltage u1=upn of the capacitor C1 may be considered as a ground fault on the output side of the motor controller.
In step S23, in the case where it is determined that the capacitance voltage of the motor controller is smaller than the first preset voltage, it is determined that the output side of the motor controller is grounded normally. If the capacitance voltage U1 of the motor controller is smaller than the first preset voltage, it is indicated that the voltage u1 noteq of the capacitor C1 is UPN, that is, the output side of the motor controller is grounded normally.
In step S24, if it is determined that the current zero vector is not V0, it is determined whether or not the current zero vector is V7. If the current zero vector is not V0, it needs to be determined again whether the current zero vector is V7, and if the zero vector is V7, it indicates that all of the upper arm switching devices S1, S3, and S5 of the motor controller are turned on, and all of the lower arm switching devices S2, S4, and S6 are turned off, which may also be indicated as (111), specifically, as shown in fig. 7. If the current sampling point is a non-zero vector V0 or a non-zero vector V7, the capacitor voltage U1 is not determined.
In step S25, in the case where it is determined that the current zero vector is V7, it is determined whether the capacitance voltage of the motor controller is less than or equal to the second preset voltage. If the current zero vector is V7, the magnitude of the capacitor voltage C2 needs to be determined.
In step S26, in the case where it is determined that the capacitance voltage of the motor controller is less than or equal to the second preset voltage, it is determined that the ground fault occurs on the output side of the motor controller. In fig. 7, capacitors C1 and C2 are connected across the positive bus P and the vehicle body ground between the positive bus and the vehicle body ground of the motor controller, wherein two ends of C1 are respectively connected with the positive bus P and the vehicle body ground, and two ends of C2 are respectively connected with the negative bus N and the vehicle body ground. Under normal conditions, the voltage at two ends of the capacitor C1 is 1/2 of the bus voltage UPN, under the condition that the PWM output zero vector is V7, the three phase line at the AC output side is simultaneously connected to the positive bus P, if any phase is grounded, the positive bus P and the ground are equipotential, and the voltage U1 at two ends of the capacitor C1 is 0. In practical situations, a threshold voltage Uth2 (a second preset voltage) may be set, and when the voltage of the capacitor C1 is smaller than the threshold voltage, the voltage u1=0 of the capacitor C1 may be considered as a ground fault on the output side of the motor controller.
In step S27, in the case where it is determined that the capacitance voltage of the motor controller is greater than the second preset voltage, it is determined that the output side of the motor controller is grounded normally. If the capacitance voltage C1 of the motor controller is greater than the second preset voltage, the voltage u1 noteq 0 of C1 is indicated, and the output side of the motor controller is grounded normally.
In steps S20 to S27, the acquired zero vector is first determined to determine whether the current zero vector is V0. If the zero vector is V0, whether the capacitance voltage U1 of the motor controller is larger than or equal to the first preset voltage needs to be continuously judged, if the capacitance voltage U1 of the motor controller is larger than or equal to the first preset voltage, the motor controller is indicated to output to have the ground fault, otherwise, the motor controller is normal. If the zero vector is not V0, continuing to judge whether the zero vector is V7 or not; if the zero vector is V7, whether the AC output side of the motor controller is grounded normally is determined according to whether the capacitor voltage is smaller than or equal to the second preset voltage, so that the rapid diagnosis of the grounding fault of the output side of the motor controller is realized, the grounding fault of the output side to the ground of the vehicle body can be detected in millisecond-level time, and the safety and reliability of the whole vehicle are effectively improved.
In this embodiment of the present invention, regarding the relationship between the first preset voltage and the second preset voltage, the sum of the first preset voltage and the second preset voltage may be equal to the bus voltage, i.e., the diagnosis of the output side of the motor controller may be reliably performed. Specifically, the first preset voltage includes, but is not limited to, UPN, and the second preset voltage includes, but is not limited to, 0.
In this embodiment of the invention, if Continuous Pulse Width Modulation (CPWM) is used, zero vectors V0 and V7 are present simultaneously in each switching period; if Discontinuous Pulse Width Modulation (DPWM) is used, either a zero vector V0 or a zero vector V7 is used in each switching period. Taking continuous pulse width modulation as an example, it can be seen in fig. 8. Specifically, in fig. 8, ua, ub, and uc are output three-phase voltage modulation signals, which are modulated with a triangular modulation wave to generate three-phase arm switching control signals Sa, sb, and Sc, and are combined into different vectors. In one switching period Ts, zero vectors V0 and V7 are simultaneously contained, wherein the midpoint of the zero vector V0 is aligned with the triangular modulation wave crest and the midpoint of the zero vector V7 is aligned with the triangular modulation wave trough. In the case of DPWM, there is only one zero vector of V0 or V7 in one switching period Ts, and the midpoint of the zero vector is also aligned with the peak or trough of the triangular modulated wave. The peaks and troughs of the triangular modulation wave are usually sampling time points of the motor controller on signals such as bus voltage UPN, output current, motor rotating speed and the like. Specifically, according to the invention, by adding the sampling to the voltage U1 of the capacitor C1 on hardware and reading the U1 sampling value at the sampling time points on software, namely at the moments t0, t1 and t2 in fig. 8, the output side can be judged whether the grounding state exists or not by combining the current zero vector state.
In this embodiment of the present invention, in order to prevent false triggering by a fault, a plurality of detection determinations may be performed. For example, every 10mS is taken as a detection and judgment period, if the switching frequency of the motor controller is 4khz, one detection and judgment period can be detected and judged 80 times when the cpwm sends waves, one detection and judgment period can be detected and judged 40 times when the DPWM sends waves, and after the ground fault is detected to reach a certain number of times in each detection period, the ground fault is finally judged as a fault and is processed, so that the reliability of ground fault judgment can be improved. Specifically, the detection time of 10mS is only an example, and the detection time can be properly increased or shortened in the specific implementation, and is far smaller than the detection time of the insulation detector, so that the output can be blocked quickly before the grounding capacitor and the capacitor loop are damaged or have enlarged faults, and the safety of the whole vehicle and the personnel is greatly improved.
In this embodiment of the present invention, in order to further improve reliability and accuracy of the diagnosis of the ground fault on the output side of the motor controller, it is also necessary to make a plurality of determinations of the zero vector and the capacitance voltage U1 on the output side of the motor controller, and the specific steps may be as shown in fig. 3. Specifically, in fig. 3, the detection method may further include:
in step S30, a detection judgment period is preset. The detection and judgment period of the zero vector and the capacitor voltage U1 is preset in advance, the sampling time is calculated in time, and if the sampling time reaches the detection and judgment period, the zero clearing and the reckoning are performed, namely, the zero clearing and the reckoning are performed after one detection period is completed.
In step S31, the value of the initialization counter and the sampling time are 0.
In step S32, it is determined whether or not the current zero vector is V0.
In step S33, when it is determined that the current zero vector is V0, it is determined whether or not the capacitance voltage of the motor controller is the bus voltage UPN. The determination of the capacitance voltage U1 of the motor controller may also be whether the capacitance voltage U1 is greater than or equal to a first preset voltage.
In step S34, in the case where it is determined that the capacitance voltage of the motor controller is the bus voltage, the value of the current time of the counter is calculated according to formula (1),
σ i ＝σ i-1 +1， (1)
wherein sigma i Sigma is the value of the current moment of the counter i-1 I is an integer number, which is the value at the last time of the counter. Specifically, in the case where the zero vector is V0 and the capacitor voltage is greater than or equal to the first preset voltage (including the bus voltage UPN), the motor controller is described as storingAt the risk of a ground fault, the counter value is incremented by one, i.e. the number of risk times of the ground fault is counted.
In step S35, if it is determined that the current zero vector is not V0, it is determined whether or not the current zero vector is V7. If the current sampling point is neither V0 nor V7, the capacitor voltage U1 is not determined.
In step S36, if it is determined that the current zero vector is V7, it is determined whether or not the capacitance voltage of the motor controller is 0. The diagnosis condition of the capacitor voltage U1 under the condition that the zero vector is V7 may further include whether the zero vector is less than or equal to the second preset voltage.
In step S37, in the case where it is determined that the capacitance voltage of the motor controller is 0, the value of the current time of the counter is calculated according to formula (1). If the capacitance voltage U1 under the condition that the zero vector is V7 is less than or equal to the second preset value (including 0), it is indicated that the motor controller has a risk of the ground fault, and the counter value is incremented by one, that is, the number of times of the risk of the ground fault is counted.
In step S38, it is determined whether the sampling time is greater than or equal to the detection determination period.
In step S39, if the sampling time is greater than or equal to the detection determination period, the sampling period is cleared, and it is determined whether the value of the current time of the counter is greater than or equal to the preset threshold. And if the sampling time is greater than or equal to the detection judging period, namely after finishing diagnosis of a complete detection judging period, resetting the sampling time for rechemg, and judging the value of the counter.
In step S40, in the case where it is determined that the value of the current time of the counter is greater than or equal to the preset threshold value, it is determined that the ground fault occurs on the output side of the motor controller. If the value of the current moment of the counter is larger than or equal to a preset threshold value, namely that the diagnosed grounding fault risk times are excessive, the occurrence of the grounding fault on the output side of the motor controller can be determined.
In step S41, if it is determined that the value of the current time of the counter is smaller than the preset threshold, it is determined that the output side of the motor controller is grounded normally. If the value of the current moment of the counter is smaller than a preset threshold value, the situation that the diagnosed ground fault risk is too small in number of times is indicated, the possibility of misdiagnosis exists, and the output side of the motor controller is judged to be grounded normally.
In step S42, when the sampling time is less than the detection determination period, the current zero vector and the capacitor voltage of the motor controller are collected. If the sampling time is less than the detection and judgment period, it indicates that the ground fault diagnosis of one completed detection and judgment period is not completed, and zero vector and capacitor voltage need to be continuously collected for diagnosis.
In step S30 to step S42, the duration of the detection and judgment period is preset, the ground fault of the output side of the motor controller is diagnosed in the detection and judgment period, and if the number of times of the diagnosed ground fault risks is greater than or equal to a preset threshold value, the existence of the ground fault of the output side of the motor controller is indicated; if the diagnosed grounding fault risk number is smaller than the preset threshold value, the fact that misdiagnosis exists is indicated that the output side of the motor controller is grounded normally, and therefore accuracy and precision of the diagnosis of the grounding fault of the output side of the motor controller can be improved, and misdiagnosis is avoided.
In this embodiment of the present invention, in order to further improve the reliability and accuracy of the ground fault diagnosis on the output side of the motor controller, it is also necessary to make a plurality of determinations of the zero vector and the capacitance voltage U1 on the output side of the motor controller, and the specific steps may be as shown in fig. 4. Specifically, in fig. 4, the detection method may further include:
in step S50, the value of the initialization counter is 0.
In step S51, it is determined whether or not the current zero vector is V0.
In step S52, if it is determined that the current zero vector is V0, it is determined whether or not the capacitance voltage of the motor controller is the bus voltage. Wherein, similarly, the judgment on the capacitance voltage U1 of the motor controller includes, but is not limited to, whether it is greater than or equal to the first preset voltage.
In step S53, when it is determined that the capacitor voltage of the motor controller is the bus voltage, the counter is incremented by one. The zero vector is V0, and the capacitor voltage U1 is the bus voltage UPN (or greater than or equal to the first preset voltage), which indicates that the output side of the motor controller has a risk of a ground fault, and counts the times of the risk of the ground fault.
In step S54, if it is determined that the capacitor voltage of the motor controller is not the bus voltage, the counter is decremented by one. If the zero vector is V0 and the capacitor voltage U1 is not the bus voltage UPN (or is smaller than the first preset voltage), it is indicated that the output side of the motor controller has no risk of a ground fault, and the number of times of the ground fault risk is reduced by one.
In step S55, if it is determined that the current zero vector is not V0, it is determined whether or not the current zero vector is V7.
In step S56, if it is determined that the current zero vector is V7, it is determined whether or not the capacitance voltage of the motor controller is 0. The condition for determining the capacitance voltage U1 in the case where the zero vector is V7 may further include whether the capacitance voltage U1 is less than or equal to the second preset voltage.
In step S57, when it is determined that the capacitance voltage of the motor controller is 0, the value of the timer is incremented by one. If the zero vector is V7 and the capacitance voltage U1 is 0 (or less than or equal to the second preset voltage), it indicates that the output side of the motor controller has a risk of a ground fault, and the number of times of the ground fault risk is counted.
In step S58, in the case where it is determined that the capacitance voltage of the motor controller is not 0, the value of the counter is decremented by one. If the zero vector is V7 and the capacitance voltage U1 is not 0 (or greater than the second preset voltage), it is indicated that the output side of the motor controller has no risk of the ground fault, and the number of times of the ground fault risk is reduced by one.
In step S59, it is determined whether the value of the counter is greater than or equal to a preset threshold.
In step S60, in the case where the value of the judgment counter is greater than or equal to the preset threshold value, it is judged that the ground fault occurs on the output side of the motor controller. If the numerical value of the counter is larger than or equal to the preset threshold value, the situation that the ground fault risk exists under the condition that the preset threshold value is continuously diagnosed is indicated, the ground fault of the motor controller can be judged, and then the fault can be rapidly blocked and output.
In step S61, in the case where the value of the judgment counter is smaller than the preset threshold, it is judged that the output side of the motor controller is grounded normally. If the value of the counter is smaller than the preset threshold value, the two groups of diagnosis are less in the number of times of the risk of the ground fault, and the diagnosis error exists, so that the output side of the motor controller can be judged to be grounded normally.
In steps S50 to S61, the diagnosis of the ground fault on the output side of the motor controller is continued, and if there is a risk of the ground fault, the counter is incremented by one, and otherwise decremented by one. When the numerical value of the counter reaches a preset threshold value, the accumulation means that the frequency of continuously diagnosing that the motor controller has more and more grounding fault risks, and the motor controller can be judged to have the grounding faults, so that the output can be blocked quickly, and the safety of the whole vehicle and personnel is greatly improved.
In this embodiment of the present invention, for the determination of the values of the first preset voltage and the second preset voltage, predictive conversion may be performed based on historical data, and specifically, the steps may be as shown in fig. 5. Specifically, in fig. 5, the detection method may further include:
in step S70, the value of the capacitance voltage U1 in the history data with zero vector V0 and the ground fault is obtained, and a first data set is formed.
In step S71, the data in the first data set is preprocessed to form a first new data set. Among them, the pretreatment method includes but is not limited to normalization method and the like.
In step S72, the value of the first preset voltage is calculated according to formula (2),
wherein U is *1 At the value of the first preset voltage,
i is an integer number, i e n, n is an integer number, and n is the number of data in the first new data set.
In step S73, the value of the capacitance voltage U1 in the history data with zero vector V7 and the ground fault is present is acquired, and a second data set is formed.
In step S74, the data in the second data set is preprocessed to form a second new data set. Among them, the pretreatment method includes but is not limited to normalization method and the like.
In step S75, the value of the second preset voltage is calculated according to formula (3),
wherein U is *2 At the value of the second preset voltage,
j is an integer number, j e m, m is an integer number, and m is the number of data in the second new data set.
In step S70 to step S75, the value of the capacitor voltage when the ground fault occurs in the history data is obtained, the capacitor voltage is calculated to obtain an average value, and the average value is used as the first preset voltage or the second preset voltage, so that the accuracy and the reliability of the ground fault diagnosis on the output side of the motor controller can be further improved.
According to the technical scheme, the detection method of the grounding fault of the motor controller output side is characterized in that the current zero vector and the capacitor voltage of the motor controller are obtained, the grounding state of the motor controller is determined according to the type of the current zero vector of the motor controller, and then the grounding fault of the motor controller output side can be rapidly detected and diagnosed by combining the magnitude of the capacitor voltage of the current motor controller; meanwhile, after the ground fault of the output side of the motor controller is detected, the output is blocked quickly, abnormal charge and discharge of the ground capacitor and the ground capacitor loop for a long time are avoided, the safety of the whole vehicle is improved, and further increase of loss is avoided.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, etc., such as Read Only Memory (ROM) or flash memory (flashRAM). Memory is an example of a computer-readable medium.
Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transshipment) such as modulated data signals and carrier waves.
It should also be noted that the terms "comprises," "comprising," or any other variation 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 may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.
Claims (10)
1. A method for detecting a ground fault at an output side of a motor controller, comprising:
collecting the current zero vector and the capacitor voltage of a motor controller;
and detecting the ground fault of the output end of the motor controller according to the capacitance voltage of the motor controller and the current zero vector type.
2. The method of detecting according to claim 1, wherein detecting the motor controller output-side ground fault according to the magnitude of the capacitance voltage of the motor controller and the class of the zero vector comprises:
judging whether the current zero vector is V0 or not;
under the condition that the current zero vector is V0, judging whether the capacitance voltage of the motor controller is larger than or equal to a first preset voltage;
under the condition that the capacitance voltage of the motor controller is larger than or equal to a first preset voltage, judging that the output side of the motor controller has a ground fault;
and under the condition that the capacitance voltage of the motor controller is smaller than a first preset voltage, judging that the output side of the motor controller is grounded normally.
3. The method of detecting according to claim 2, wherein detecting the motor controller output-side ground fault according to the magnitude of the capacitance voltage of the motor controller and the class of the zero vector further comprises:
judging whether the current zero vector is V7 or not under the condition that the current zero vector is not V0;
under the condition that the current zero vector is V7, judging whether the capacitance voltage of the motor controller is smaller than or equal to a second preset voltage;
under the condition that the capacitance voltage of the motor controller is smaller than or equal to a second preset voltage, judging that the output side of the motor controller has a ground fault;
and under the condition that the capacitance voltage of the motor controller is larger than a second preset voltage, judging that the output side of the motor controller is grounded normally.
4. A detection method according to claim 3, wherein the sum of the first preset voltage and the second preset voltage is equal to a bus voltage.
5. The method of detecting according to claim 1, wherein detecting the motor controller output-side ground fault according to the magnitude of the capacitance voltage of the motor controller and the type of the current zero vector comprises:
presetting a detection judging period;
initializing the value of a counter and sampling time to be 0;
judging whether the current zero vector is V0 or not;
judging whether the capacitance voltage of the motor controller is bus voltage or not under the condition that the current zero vector is V0;
under the condition that the capacitance voltage of the motor controller is judged to be the bus voltage, calculating the numerical value of the current moment of the counter according to a formula (1),
σ i ＝σ i-1 +1， (1)
wherein sigma i Sigma, which is the value of the current moment of the counter i-1 I is an integer number for the value of the last moment of the counter.
6. The method of detecting according to claim 5, wherein detecting the motor controller output-side ground fault based on the magnitude of the capacitance voltage of the motor controller and the type of the current zero vector further comprises:
judging whether the current zero vector is V7 or not under the condition that the current zero vector is not V0;
under the condition that the current zero vector is V7, judging whether the capacitance voltage of the motor controller is 0 or not;
and under the condition that the capacitance voltage of the motor controller is judged to be 0, calculating the value of the current moment of the counter according to the formula (1).
7. The method of detecting according to claim 6, wherein detecting the motor controller output side ground fault based on the magnitude of the capacitance voltage of the motor controller and the current zero vector class further comprises:
judging whether the sampling time is greater than or equal to the detection judging period;
under the condition that the sampling time is larger than or equal to the detection judging period, the sampling period is cleared, and whether the value of the current moment of the counter is larger than or equal to a preset threshold value is judged;
under the condition that the value of the current moment of the counter is larger than or equal to a preset threshold value, judging that the output side of the motor controller has a ground fault;
under the condition that the value of the current moment of the counter is smaller than a preset threshold value, the output side of the motor controller is judged to be grounded normally;
and returning to collect the current zero vector and the capacitor voltage of the motor controller under the condition that the sampling time is smaller than the detection judging period.
8. The method of detecting according to claim 1, wherein detecting the motor controller output-side ground fault according to the magnitude of the capacitance voltage of the motor controller and the type of the current zero vector comprises:
initializing the value of a counter to 0;
judging whether the current zero vector is V0 or not;
judging whether the capacitance voltage of the motor controller is bus voltage or not under the condition that the current zero vector is V0;
under the condition that the capacitance voltage of the motor controller is judged to be the bus voltage, the value of the counter is increased by one;
and under the condition that the capacitance voltage of the motor controller is judged not to be the bus voltage, the value of the counter is reduced by one.
9. The method of detecting according to claim 8, wherein detecting the motor controller output side ground fault based on the magnitude of the motor controller capacitance voltage and the current zero vector class further comprises:
judging whether the current zero vector is V7 or not under the condition that the current zero vector is not V0;
under the condition that the current zero vector is V7, judging whether the capacitance voltage of the motor controller is 0 or not;
under the condition that the capacitance voltage of the motor controller is judged to be 0, the value of the counter is increased by one;
and under the condition that the capacitance voltage of the motor controller is judged to be not 0, the value of the counter is reduced by one.
10. The method of detecting of claim 9, wherein detecting the motor controller output ground fault based on the magnitude of the motor controller capacitance voltage and the current zero vector class further comprises:
judging whether the numerical value of the counter is larger than or equal to a preset threshold value;
under the condition that the numerical value of the counter is larger than or equal to a preset threshold value, judging that the output side of the motor controller has a ground fault;
and under the condition that the numerical value of the counter is smaller than a preset threshold value, judging that the output side of the motor controller is grounded normally.
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