CN112034385A - Motor system fault detection method, device and computer readable storage medium - Google Patents
Motor system fault detection method, device and computer readable storage medium 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
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Abstract
The invention provides a motor system fault detection method, equipment and a computer readable storage medium, wherein the method comprises the steps of selecting an upper bridge switching tube of any one or more bridge arms, inputting a preset pulse signal to the selected upper bridge switching tube to enable the selected upper bridge switching tube to be conducted and closed according to a preset mode, selecting a lower bridge switching tube of one or more bridge arms in the rest bridge arms, inputting a preset pulse signal to the selected lower bridge switching tube to enable the selected lower bridge switching tube to be kept conducted according to a preset mode, and circulating n switching cycles; detecting the current flowing through the selected bridge arm, comparing the current with a preset current open-phase threshold value, and judging whether the current is open-phase or not; or detecting the pulse frequency of the selected bridge arm, comparing the pulse frequency with a preset pulse open-phase threshold value, and judging whether the phase is open. When the fault detection is carried out on the motor system of the new energy automobile, the phase-failure fault detection and the short-distance fault detection can be simultaneously realized, and the position of a fault short-distance place can be accurately determined.
Description
Technical Field
The invention relates to the technical field of new energy automobiles, in particular to a motor system fault detection method, motor system fault detection equipment and a computer readable storage medium.
Background
In order to improve the electromagnetic compatibility (EMC) of the system, a Y capacitor is usually connected in series between the positive electrode of the high-voltage power battery and the vehicle body, and between the negative electrode of the high-voltage power battery and the vehicle body, so as to filter out common-mode interference signals. The Y capacitor passes very little current during normal operation, and typically experiences very little nominal current to accommodate cost and volume requirements. When one phase of the AC side of the inverter has short casing or one phase of the motor has abnormal insulation, the motor controller is changed from a power loop formed by a battery, a bus capacitor, a switching tube and a motor into a power loop formed by the battery, the bus capacitor, the switching tube, the motor, a Y capacitor and a casing (ground). Therefore, high-frequency oscillation current is formed in the Y capacitor, and is limited by the Hall, the bandwidth of the conditioning circuit and the sampling frequency of software, the motor controller cannot detect abnormal current, and devices such as the Y capacitor, a fuse and the Hall can be burnt by large current for a long time.
The method mainly comprises a hardware detection device and a software detection method for detecting the single-phase-to-ground short circuit fault output by the motor controller. The typical hardware method is to connect an induction device in series with the Y capacitor branch or detect the voltage change of the Y capacitor or detect the characteristic quantity of the output side to realize fault detection. The typical software method is a method of outputting three-phase current imbalance by adopting a motor controller.
For convenience of description, the short circuit of the motor controller output single phase to the housing is abbreviated as "short ground" hereinafter.
In the prior art, short-circuit detection is usually performed before phase failure detection, but the reason is that when the motor controller is powered on and initialized, the phase failure detection is performed, whether the phase failure occurs or not is identified according to the winding current, and when the output is short-circuited to the shell, a fault cannot be detected, and the risk of damaging the device exists.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention mainly aims to provide a motor system fault detection method, equipment and a computer readable storage medium, aiming at solving the problems of simultaneously realizing open-phase fault detection and short-distance fault detection and determining the position of a fault short-distance place when the motor system of a new energy automobile is subjected to fault detection under the condition of not increasing the (hardware) cost.
In order to achieve the above object, the present invention provides a method for detecting a fault of a motor system, wherein the motor system comprises an inverter and a motor; the inverter comprises n bridge arms, each bridge arm comprises an upper bridge switching tube and a lower bridge switching tube, the motor comprises n motor windings, the n motor windings are connected with the n bridge arms in a one-to-one correspondence mode, n is a positive integer, the method is executed when the motor is in a stop state, and the method comprises the following steps:
selecting an upper bridge switching tube of any one or more bridge arms, inputting a preset pulse signal to the selected upper bridge switching tube to enable the selected upper bridge switching tube to be switched on and off according to a preset mode, selecting a lower bridge switching tube of one or more bridge arms in the rest bridge arms, and inputting a preset pulse signal to the selected lower bridge switching tube to enable the selected lower bridge switching tube to be kept switched on according to the preset mode, and circulating n switching cycles;
and detecting the current flowing through the selected bridge arm, comparing the current with a preset current open-phase threshold value, and judging whether the current is open-phase or not.
Preferably, in case of judging a phase loss, it is judged whether or not a short-circuit occurs, based on a comparison of the detected current with a preset current short-circuit threshold.
Preferably, the current open-phase threshold is non-overlapping with the current short-ground threshold range; when the detected current is smaller than the current open-phase threshold value, judging that the current is open-phase; when the detected current is larger than the current open-phase threshold and smaller than the current short-ground threshold, judging that the open phase does not generate short ground; and when the detected current is larger than the current short-ground threshold value, judging as short ground.
Preferably, the current open-phase threshold is calculated by the following formula:
wherein, IRZIndicating the current open-phase threshold, UdRepresenting bus voltage, L representing motor winding inductance, N representing number of pulses, TsiDenotes the ith switching cycle, DiAnd the on duty ratio of the upper bridge switching tube is shown.
Preferably, the current open-phase threshold is adjusted according to a current calculation error and a hall sampling error, and the current open-phase threshold ranges from:
wherein, IRZIndicating the current open-phase threshold, UdRepresenting bus voltage, L representing motor winding inductance, N representing number of pulses, TsiDenotes the ith switching cycle, DiThe on duty ratio of the upper bridge switching tube is shown,A、A1and error values representing current calculation errors and Hall sampling errors.
Preferably, the current ground threshold is calculated by the following equation:
wherein, IDRZRepresenting the current short-earth threshold, CYRepresenting the one-sided capacitance magnitude of the safety capacitance.
Preferably, the current short-ground threshold is adjusted according to a current calculation error and a hall sampling error, and the current open-phase threshold is within a range of:
wherein IDRZ represents the current short-ground threshold, CY represents the one-sided capacitance size of the safety capacitor,A、A1represents the current calculation error,Error value of hall sampling error.
In addition, in order to achieve the above object, the present invention further provides a method for detecting a fault of a motor system, wherein the motor system comprises an inverter and a motor; the inverter comprises n bridge arms, each bridge arm comprises an upper bridge switching tube and a lower bridge switching tube, the motor comprises n motor windings, the n motor windings are connected with the n bridge arms in a one-to-one correspondence mode, n is a positive integer, the method is executed when the motor is in a shutdown state, and the method comprises the following steps:
selecting an upper bridge switching tube of any one or more bridge arms, inputting a preset pulse signal to the selected upper bridge switching tube to enable the selected upper bridge switching tube to be switched on and off according to a preset mode, selecting a lower bridge switching tube of one or more bridge arms in the rest bridge arms, and inputting a preset pulse signal to the selected lower bridge switching tube to enable the selected lower bridge switching tube to be kept switched on according to the preset mode, and circulating n switching cycles;
and detecting the pulse frequency of the selected bridge arm, comparing the pulse frequency with a preset pulse open-phase threshold value, and judging whether the phase is open.
Preferably, in the case of determining a phase loss, whether the phase loss is caused is determined by comparing the detected number of pulses with a preset pulse ground threshold.
Preferably, the pulse open-phase threshold has no overlap with the pulse short-ground threshold range; when the detected pulse frequency is greater than the pulse open-phase threshold, judging that the pulse is open-phase; when the detected pulse number is smaller than the pulse open-phase threshold and larger than the pulse short-ground threshold, judging that no open-phase and no short-ground occur; and when the detected pulse frequency is less than the pulse short-ground threshold value, judging the pulse is short-ground.
Preferably, the pulse open-phase threshold or the pulse short-ground threshold is used as a reference by reading the number of pulses when the motor system operates in a normal state, and the reference range is adjusted according to a current calculation error and a hall sampling error.
In addition, in order to achieve the above object, the present invention further provides a motor system short circuit detection device, which includes a memory and a processor, wherein the memory stores a computer program operable on the processor, and the processor implements the steps of the motor system fault detection method as described above when executing the computer program.
Furthermore, to achieve the above object, the present invention further provides a computer readable storage medium, having a computer program stored thereon, which, when being executed by a processor, implements the steps of the motor system fault detection method as described above.
The invention has the beneficial effects that: the invention provides a motor system fault detection method, equipment and a computer readable storage medium, which can be applied to the technical field of new energy automobiles, wherein an upper bridge switching tube of any one or more bridge arms is selected at first, a preset pulse signal is input into the selected upper bridge switching tube, so that the selected upper bridge switching tube is switched on and off in a preset mode, then a lower bridge switching tube of one or more bridge arms in the rest bridge arms is selected, a preset pulse signal is input into the selected lower bridge switching tube, so that the selected lower bridge switching tube is kept on in the preset mode, and n switching periods are circulated; finally, detecting the current flowing through the selected bridge arm, and comparing the current with a preset current open-phase threshold value to judge whether the current is open-phase or not; or the pulse frequency of the selected bridge arm is detected and compared with a preset pulse open-phase threshold value to judge whether the open phase exists or not, so that open-phase fault detection and short-distance fault detection can be simultaneously realized when a motor system of the new energy automobile is subjected to fault detection, the position of a fault short-distance place can be accurately determined, and the hardware cost is not increased.
Drawings
FIG. 1a is a schematic flow chart of a method for detecting a fault in an electric machine system according to the present invention;
FIG. 1b is another schematic flow chart of a method for detecting a fault in an electric machine system according to the present invention;
FIG. 2a is a schematic circuit diagram of a method for detecting a fault in a motor system according to the present invention;
fig. 2b is a schematic diagram of a principle of a three-phase winding of a circuit of the fault detection method for a motor system according to the embodiment of the present invention;
FIG. 2c is a schematic diagram of waveforms of the driving signals according to the embodiment of the present invention;
FIG. 3a is a schematic diagram of the conducting state 1 of the upper and lower arm switches in stage 1 when the winding is not grounded;
FIG. 3b is a schematic diagram of the upper and lower bridge arm switches conducting in phase 1 when the winding is not shorted to ground in state 2 of the present invention;
FIG. 4a is a schematic diagram of the conducting state 1 of the upper and lower arm switches in phase 2 when the winding is not grounded;
FIG. 4b is a schematic diagram of the upper and lower bridge arm switches conducting in phase 2 when the winding is not shorted to ground in state 2 of the present invention;
FIG. 5a is a schematic diagram of the upper and lower bridge arm switches conducting in phase 3 when the winding is not shorted at state 1 of the present invention;
FIG. 5b is a schematic diagram of the upper and lower bridge arm switches conducting in phase 3 when the winding is not shorted in the present invention in state 2;
FIG. 6 is a diagram illustrating the detection current when the open-phase threshold is set according to the present invention;
FIG. 7 is a diagram illustrating the detection of pulses when the phase-loss threshold is set according to the present invention;
FIG. 8a is a schematic diagram of the upper and lower arm switches conducting in phase 1 when the winding is short to ground according to the present invention in state 1;
FIG. 8b is a schematic diagram of the upper and lower arm switches conducting in phase 1 when the winding is short to ground according to the present invention in state 2;
FIG. 9a is a diagram showing the conducting state of the upper and lower arm switches at stage 2 when the winding is short to ground in accordance with the present invention in state 1;
FIG. 9b is a diagram of the upper and lower arm switches conducting in phase 2 when the winding is short to ground according to the present invention in state 2;
FIG. 10a is a diagram of the conducting state 1 of the upper and lower arm switches in phase 3 when the winding is short-circuited according to the present invention;
FIG. 10b is a schematic diagram of the upper and lower arm switches conducting in phase 3 when the winding is short to ground in state 2 according to the present invention;
FIG. 11 is a diagram illustrating the detection current when the ground threshold is set according to the present invention;
FIG. 12 is a schematic diagram of the detection pulse when the ground threshold is set according to the present invention;
FIG. 13 is a logic diagram of phase loss and short-circuit detection according to an embodiment of the method for detecting a fault in a motor system provided by the present invention;
fig. 14 is a schematic block diagram of a motor system fault detection apparatus in an embodiment of the present invention.
The objects, features and advantages of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In order to solve the above technical problem, this embodiment provides a method for detecting a fault of a motor system, and referring to fig. 1a, fig. 1a is a schematic flow chart of the method for detecting a fault of a motor system in an embodiment of the present invention.
Specifically, referring to fig. 2a, fig. 2a is a schematic circuit schematic diagram of a motor system fault detection method provided by an embodiment of the present invention, and as shown in fig. 2a, is also a structural block diagram of a power system of a new energy vehicle, the motor system fault detection method is applied to the new energy vehicle, and as shown in fig. 2a, the motor system fault detection method includes a power battery 1, a PN cable, an EMC filtering unit 3, a bus support capacitor 4, an inverter bridge 5, an AC hall 6, an AC cable 7 (where the AC cable 7 is composed of a cable 71 and a cable 72 … in fig. 2), a motor 8, and a vehicle body 9. The PN cable is composed of a bus positive cable 21 and a bus negative cable 22. The EMC filtering unit 3 is composed of a bus positive side Y capacitor 31, a bus negative side Y capacitor 32 and a Y capacitor grounding end 33, wherein the Y capacitor is a safety capacitor. The inverter bridge 5 is composed of n bridge arms, a motor controller shell 54 and a motor controller shell grounding end 55, wherein the bridge arm 51 is composed of an upper bridge switching tube 511, a lower bridge switching tube 512 and an output port 513, the bridge arm 52 is composed of an upper bridge switching tube 521, a lower bridge switching tube 522 and an output port 523, and the bridge arm 5n3 is composed of an upper bridge switching tube 5n1, a lower bridge switching tube 5n2 and an output port 5n 3. AC cable 7 is composed of n cables, one end of cable 71 is connected with output port 513 of bridge arm 51, one end of cable 72 is connected with output port 523 of bridge arm 52, and one end of cable 7n is connected with output port 5n3 of bridge arm 5 n. The motor 8 is composed of a motor housing 81, windings, a motor port 83 and a motor housing grounding end 84, wherein the windings are divided into n phases and numbered 821, 822 and 82n in sequence. The motor port 83 is composed of n terminals numbered 831, 832 … 83n in sequence. Y capacitor ground 33, motor controller housing 54 ground 55, and motor housing 81 ground 84 are connected to vehicle body 9, respectively.
The connection mode is specifically as follows: the positive pole of the power battery 1 is connected with a bus positive cable 21, and the negative pole of the power battery 1 is connected with a bus negative cable 22. The two ends of the bus positive side Y capacitor 31 are respectively connected with the bus positive cable 21 and the vehicle body 9, and the two ends of the bus negative side Y capacitor 32 are respectively connected with the bus negative cable 22 and the vehicle body 9. The two ends of the bus bar supporting capacitor 4 are respectively connected with a bus bar positive cable 21 and a bus bar negative cable 22. Collectors C of upper bridges (511, 521.. 531) of n bridge arms (51, 52.. 5n) of the inverter bridge 5 are connected to the bus bar positive cable 21 in common, and emitters E of lower bridges (512, 522, 5n2) of the n bridge arms (51, 52.. 5n) of the inverter bridge 5 are connected to the bus bar positive cable 21 in common. Output ports (513, 523, 5n3) of bridge arms (51, 52, 5n) of the inverter bridge 5 are respectively connected to one end of the AC cable 7. The other end of the AC cable 7 is connected to the motor port 83. The hall 6 in turn is connected across an AC cable 7.
The power battery 1 is responsible for supplying electric energy and feeding back stored electric energy. The PN cable is responsible for connecting the power battery 1 and the inverter bridge 5 and is used as a path for electric energy transmission. The Y capacitors (31, 32) provide low impedance paths for system common mode interference. The bus support capacitor 4 functions to smooth the bus voltage, store energy, and provide a minimum path for the inverter bridge 5. The inverter bridge 5 is used for converting direct current into alternating current for driving the motor 8 or converting alternating current into direct current for feeding energy generated by the motor 8 back to the power battery 1. The hall 6 is used for sampling the current in the output winding and controlling the inverter bridge 5. The AC cable 7 is responsible for connecting the inverter bridge 5 and the motor 8 and provides a path for power transmission. The motor 8 converts energy into mechanical energy or vice versa. The body 9 is used for mounting a power assembly device and plays a role in electrical connection. According to the technical scheme, the energy of the Y capacitor is introduced into a motor winding through the control of a switching mode, a phase-lack threshold value and a short-ground threshold value are set, and phase-lack and short-ground faults can be detected simultaneously.
In this embodiment, corresponding to the structural block diagram shown in fig. 2a, the motor system includes an inverter and a motor; the inverter comprises n bridge arms, each bridge arm comprises an upper bridge switching tube and a lower bridge switching tube, the motor comprises n motor windings, the n motor windings are connected with the n bridge arms in a one-to-one correspondence mode, and n is a positive integer;
the motor system fault detection method of the embodiment is executed in the motor stop state, and the method comprises the following steps:
step S10: selecting an upper bridge switching tube of any one or more bridge arms, inputting a preset pulse signal to the selected upper bridge switching tube to enable the selected upper bridge switching tube to be switched on and off according to a preset mode, selecting a lower bridge switching tube of one or more bridge arms in the rest bridge arms, inputting a preset pulse signal to the selected lower bridge switching tube to enable the selected lower bridge switching tube to be kept on according to the preset mode, and circulating n switching cycles;
step S20: detecting the current flowing through the selected bridge arm, comparing the current with a preset current open-phase threshold value, and judging whether the current is open-phase or not;
or detecting the pulse frequency of the selected bridge arm, comparing the pulse frequency with a preset pulse open-phase threshold value, and judging whether the phase is open.
It should be noted that, in the case of determining a phase loss, whether a short-circuit occurs is determined by comparing the detected current with a preset current short-circuit threshold; wherein the current open-phase threshold is non-overlapping with the current short-ground threshold range; when the detected current is smaller than the current open-phase threshold value, judging that the current is open-phase; when the detected current is larger than the current open-phase threshold and smaller than the current short-ground threshold, judging that the open-phase does not occur short-ground; when the detected current is larger than the current short-ground threshold value, judging the current short-ground threshold value as short ground;
or
Under the condition of judging the phase lack, judging whether the phase is short according to the comparison of the detected pulse times and a preset pulse short threshold; wherein the pulse open-phase threshold is not overlapped with the pulse short-ground threshold range; when the detected pulse frequency is greater than the pulse open-phase threshold, judging that the pulse is open-phase; when the detected pulse frequency is smaller than the pulse phase-lacking threshold and larger than the pulse short-ground threshold, judging that no phase-lacking occurs and no short ground occurs; and when the detected pulse number is less than the pulse short-ground threshold value, judging the pulse is short-ground. The pulse open-phase threshold or the pulse short-ground threshold is used as a reference by reading the pulse times when the motor system operates in a normal state, and the reference range is adjusted according to the current calculation error and the Hall sampling error
In a specific implementation, the embodiment traverses the n bridge arms, and selects two different bridge arms traversed as a first bridge arm and a second bridge arm; and after the steps S10 to S20 are executed each time, the step of traversing the n bridge arms is returned until the n bridge arms are all selected, so as to determine whether each bridge arm has a phase failure and a short-circuit ground.
The specific traversal mode can group n bridge arms, a phase-one upper bridge and a phase-one lower bridge of a non-identical bridge arm are arbitrarily selected as a bridge arm group, the plurality of bridge arm groups are sequentially subjected to phase-missing judgment and/or short circuit judgment operation respectively, and the following steps are performed on each bridge arm group:
and (3) lasting for N switching periods, wherein the ith switching period is Tsi, the switching-on duty ratio of the upper (lower) bridge is Di, and the lower (upper) bridge is normally on.
The preset Pulse signal of this embodiment is a PWM (Pulse width modulation) signal, the preset Pulse signal includes a first preset Pulse signal and a second preset Pulse signal, refer to fig. 2c, and fig. 2c is a waveform diagram of the driving signal in the embodiment of the present invention. The first preset pulse signal is used for controlling an upper bridge switching tube of the first bridge arm to be conducted in a preset mode (and simultaneously a lower bridge switching tube of the second bridge arm is disconnected); the second preset pulse signal is used for controlling the lower bridge switching tube of the second bridge arm to be normally on (meanwhile, the lower bridge switching tube of the first bridge arm is disconnected).
Specifically, referring to fig. 1b, the step S20 specifically includes:
step S200, detecting the current value of the motor windings connected in series in the corresponding phases of the first bridge arm and the second bridge arm;
step S201, comparing the current value of the series motor winding with the default phase threshold value; executing step S202 when the current value of the series motor winding is smaller than the default phase threshold value; and executing the step S203 when the current value of the series motor windings is not less than the open-phase threshold value.
And S202, judging that the corresponding phase of the first bridge arm and/or the second bridge arm is broken.
Step S203: comparing the current value of the series motor winding with the short-earth threshold value; when the current value of the series motor winding is larger than the short-earth threshold value, executing step 204; when the current value of the series motor winding is not greater than the short-ground threshold, step 205 is executed.
Step 204: judging a corresponding phase short circuit of the first bridge arm;
step 205: and judging that the corresponding phases of the first bridge arm and the second bridge arm have no open circuit and no short circuit.
The beneficial effect of this embodiment lies in: in the process of executing the motor system fault detection method, an upper bridge switching tube of any one or more bridge arms is selected, a preset pulse signal is input to the selected upper bridge switching tube, so that the selected upper bridge switching tube is turned on and turned off in a preset mode, then a lower bridge switching tube of one or more bridge arms in the rest of bridge arms is selected, a preset pulse signal is input to the selected lower bridge switching tube, so that the selected lower bridge switching tube is kept on in the preset mode, and n switching periods are cycled; finally, detecting the current flowing through the selected bridge arm, and comparing the current with a preset current open-phase threshold value to judge whether the current is open-phase or not; or the pulse frequency of the selected bridge arm is detected and compared with a preset pulse open-phase threshold value to judge whether the phase is open or not, so that open-phase fault detection and short-ground fault detection can be simultaneously realized when a motor system of the new energy automobile is subjected to fault detection, the position of a fault short-ground point can be accurately determined, and the hardware cost is not increased.
For ease of understanding, in a specific implementation, the present embodiment is described with the motor windings as three phases, and refer to fig. 2 b. Fig. 2b is a schematic diagram of a principle when a winding of a circuit of the motor system fault detection method provided by the embodiment of the present invention is three-phase, in fig. 2b, a switching mode is totally divided into three stages, an inverter bridge 5 is composed of a bridge arm 51, a bridge arm 52, a bridge arm 53, a motor controller housing 54, and a motor controller housing ground terminal 55, wherein the bridge arm 51 is composed of an upper bridge switching tube 511, a lower bridge switching tube 512, and an output port 513, the bridge arm 52 is composed of an upper bridge switching tube 521, a lower bridge switching tube 522, and an output port 523, and the bridge arm 53 is composed of an upper bridge switching tube 531, a lower bridge switching tube 532, and an output port 533. The AC cable 7 is composed of 3 cables, and one end of the cable 71 is connected to the output port 513 of the bridge arm 51, one end of the cable 72 is connected to the output port 523 of the bridge arm 52, and one end of the cable 73 is connected to the output port 533 of the bridge arm 53. The motor 8 is composed of a motor casing 81, a winding 82, a motor port 83 and a motor casing grounding end 84, wherein the winding 82 is divided into 3 phases which are numbered 821, 822 and 823 in sequence. The motor port 83 is composed of 3 terminals, and the numbers are 831, 832 and 833 sequentially.
The connection mode is specifically as follows: the positive pole of the power battery 1 is connected with a bus positive cable 21, and the negative pole of the power battery 1 is connected with a bus negative cable 22. The two ends of the bus positive side Y capacitor 31 are respectively connected with the bus positive cable 21 and the vehicle body 9, and the two ends of the bus negative side Y capacitor 32 are respectively connected with the bus negative cable 22 and the vehicle body 9. The two ends of the bus bar supporting capacitor 4 are respectively connected with a bus bar positive cable 21 and a bus bar negative cable 22. Collectors C of upper bridges (511, 521 and 531) of three bridge arms (51, 52 and 53) of the inverter bridge 5 are connected to the bus positive cable 21 in common, and emitters E of lower bridges (512, 522 and 532) of the three bridge arms (51, 52 and 53) of the inverter bridge 5 are connected to the bus positive cable 21 in common. Output ports (513, 523, 533) of bridge arms (51, 52, 53) of the inverter bridge 5 are respectively connected to one end of the AC cable 7. The other end of the AC cable 7 is connected to the motor port 83. The hall 6 in turn is connected across an AC cable 7.
Referring to fig. 2c, the switching mode is divided into three phases:
stage 1: and (4) randomly selecting a phase-one upper bridge and a phase-one lower bridge of a non-identical bridge arm. Sustained N1A switching period, the ith switching period is Ts1iThe on duty ratio of the upper (lower) bridge is D1iThe lower (upper) bridge is normally open.
And (2) stage: and in the rest upper and lower bridges, one-phase upper bridge and one-phase lower bridge of the non-same bridge arm are selected randomly. Sustained N2A switching period, the ith switching period is Ts2iThe on duty ratio of the upper (lower) bridge is D2iThe lower (upper) bridge is normally open.
And (3) stage: in the remaining set of upper and lower bridges. Sustained N3A switching period, the ith switching period is Ts3iThe on duty ratio of the upper (lower) bridge is D3iThe lower (upper) bridge is normally open.
Wherein N is1、N2、N3Is a positive integer, D1i、D2i、D3iThe value ranges from 0 to 1. The switching mode drive signal waveform is shown in fig. 2 c.
Several situations that may cause a motor system failure are described below:
case one, the winding is not shorted to the current in the winding in three phases:
for convenience of description, in the present embodiment, "arm 51, arm 52, and arm 53" in fig. 2b are defined as "arm U, arm V, and arm W", respectively.
In stage 1, (the first arm is arm W, i.e., arm 53, and the second arm is arm U, i.e., arm 51), it is assumed that W-phase upper bridge PWM operation is selected, and U-phase lower bridge is normally on. The switching states are divided into two, as shown in fig. 3 (fig. 3a and 3 b). And in the state 1, the W-phase upper bridge and the U-phase lower bridge are conducted, the bus voltage is applied to the U-phase and W-phase series windings, and the winding current is increased. And the state 2 is that the W-phase upper bridge is closed and the U-phase lower bridge is conducted, the winding current flows through the U-phase lower bridge and the W-phase lower bridge, and the winding current is slightly reduced and can be ignored.
Suppose for N1A switching period, the ith switching period is Ts1iThe upper bridge is on with a duty ratio of D1iAnd the lower bridge is normally open. The final winding current is about
In the formula of UdFor bus voltage, L (theta) is series inductance of UW winding, N1Number of pulses, T, co-generated for stage 1s1iFor the ith switching cycle of phase 1, D1iThe duty cycle is turned on for the stage 1 upper bridge.
In stage 2, (the first arm is arm V, i.e., arm 52, and the second arm is arm W, i.e., arm 53), it is assumed that the V-phase upper bridge PWM operation is selected, and the W-phase lower bridge is normally on. The switching states are divided into two, as shown in fig. 4 (fig. 4a and 4 b). The state 1 is that the V-phase upper bridge and the W-phase lower bridge are conducted, the bus voltage is applied to the V-phase and W-phase series windings, and the winding current is increased. And the state 2 is that the V-phase upper bridge is closed and the W-phase lower bridge is conducted, the winding current flows through the V-phase lower bridge and the W-phase lower bridge, and the winding current is slightly reduced and can be ignored.
Suppose for N2A switching period, the ith switching period is Ts2iThe upper bridge is on with a duty ratio of D2iAnd the lower bridge is normally open. The final winding current is about
In the formula of UdFor bus voltage, L (theta +2 pi/3) is a series inductor of VW winding, N2Number of pulses co-generated for stage 2, Ts2iFor the ith switching cycle of stage 2Period D of2iThe duty cycle is turned on for the stage 2 upper bridge.
In stage 3, (the first arm is arm U, i.e., arm 51, and the second arm is arm V, i.e., arm 52), it is assumed that the V-phase upper bridge PWM operation is selected, and the W-phase lower bridge is normally on. The switching states are divided into two types, as shown in fig. 5 (fig. 5a and 5 b). The state 1 is that the U-phase upper bridge and the V-phase lower bridge are conducted, the bus voltage is applied to the U-phase and V-phase series windings, and the winding current is increased. And the state 2 is that the U-phase upper bridge is closed and the V-phase lower bridge is conducted, the winding current flows through the U-phase lower bridge and the V-phase lower bridge, and the winding current is slightly reduced and can be ignored.
Suppose for N3A switching period, the ith switching period is Ts3iThe upper bridge is on with a duty ratio of D3iAnd the lower bridge is normally open. The final winding current is about
In the formula of UdFor bus voltage, L (theta-2 pi/3) is a series inductor of UV winding, N3Number of pulses, T, co-generated for stage 3s3iFor the ith switching cycle of phase 3, D3iThe duty cycle is turned on for the stage 3 upper bridge.
Further, the phase-lack threshold of the present invention is obtained by:
calculating a first reference current of the motor windings connected in series under a first set condition according to the operating parameters of the motor system in the normal state of the bridge arm group, and generating the phase-missing threshold value based on the first reference current, wherein the first set condition represents a condition when the corresponding phase of the first bridge arm and the corresponding phase of the second bridge arm are not short-circuited;
wherein the first reference current is calculated by the following equation
Is obtained by calculation of IRZRepresenting said first reference current, UdRepresenting the bus voltage, L representing the winding series inductance of the first and second arms, and N representing the generationThe number of pulses of the predetermined pulse signal, TsiDenotes the ith switching period, DiAnd representing the switching-on duty ratio of the upper bridge switching tube of the first bridge arm.
It will be appreciated that when out of phase, there is no current flow for any duration of the pulse. For example, the phase U is disconnected, and the phase 1 winding and the phase 3 winding do not generate current; the V phase is disconnected, and the windings in the stage 2 and the stage 3 cannot generate current; the W phase is open and no current is generated by the phase 1 and phase 2 windings. For example, any two phases or three phases are absent, and no current exists in the winding at any stage. Therefore, judging whether or not a phase is missing based on the current is a missing phase threshold setting method of the present invention.
In a specific implementation, as shown in fig. 6, the ordinate is the threshold current and the abscissa is the phase. Phase 1, bus voltage UdThe Hall circuit can be used for sampling the bus voltage; the winding inductance L can be obtained by calculating the motor parameters and the rotation position; the number of pulses, the switching period and the duty ratio of each stage can be set through software. The magnitude of the current generated at each stage is therefore known, as shown by points a1, a2, A3 in fig. 6.
The current calculation error and the Hall sampling error are considered, and a certain margin is reserved. The phase 1 to phase 3 default threshold ranges may be set as follows
The error values in the equations (4), (5) and (6) can be set according to actual conditions.
When the actual winding current is larger than the phase-lack threshold value through the detection of the stage 1, the stage 2, the stage 3 or any two stages, the phase-lack is judged not to be caused; and if the actual winding current is smaller than the phase-lack threshold value, judging the phase lack. If the winding current in the stage 1 and the stage 2 is smaller than the phase-lack threshold, the phase W is lacked; if the winding current in the stage 2 and the stage 3 is smaller than the phase-lack threshold, the V phase is lacked; and if the phase 1 and phase 3 winding currents are smaller than the phase-lack threshold value, the U phase is lacked. And if the winding current in the three phases is smaller than the phase-lack threshold value, two phases or three phases are arbitrarily lacked.
Further, in addition to determining whether or not a phase is missing based on the current, the present embodiment also proposes setting a phase-missing threshold based on whether or not a phase is missing determined by the pulse. Specifically, as shown in fig. 7, the ordinate is the threshold pulse number, and the abscissa is the phase. Phase 1, bus voltage UdThe Hall circuit can be used for sampling the bus voltage; the winding inductance L can be obtained by calculating motor parameters and rotation positions; the switching period, duty cycle, and reference current for each phase may be set by software. The number of pulses generated per phase is known, such as shown in fig. 6 at points B1, B2, B3.
The current calculation error and the Hall sampling error are considered, and a certain margin is reserved. The phase 1 to phase 3 default threshold ranges may be set as follows
NTB1>NB1+σB1 (7)
NTB2>NB2+σB2 (8)
NTB3>NB3+σB3 (9)
In the formula NB1、NB2、NB3The error value can be obtained by reverse deduction according to the formulas (1), (2) and (3), and the error value can be set according to the actual situation.
When the phase 1, the phase 2, the phase 3 or any two phases are detected, the actual pulse number of each phase is smaller than the phase-lack threshold value, and the phase is judged not to be phase-lack; and if the actual pulse number is larger than the phase-lack threshold value, judging the phase lack. If the pulse number of the stage 1 and the stage 2 is larger than the phase-lack threshold, the W phase is lacked; if the pulse number of the stage 2 and the stage 3 is larger than the phase-lack threshold, the V phase is lacked; if the pulse number of the stage 1 and the stage 3 is larger than the phase-lack threshold value, the U phase is lacked. If the number of the winding pulses of the three phases is larger than the threshold value, two phases or three phases are arbitrarily lacked.
Case two, the current in the winding in three phases of the winding short-term:
in stage 1, (the first arm is arm W, i.e., arm 53, and the second arm is arm U, i.e., arm 51), it is assumed that W-phase upper bridge PWM operation is selected, and U-phase lower bridge is normally on. The switching states are divided into two types, as shown in fig. 8. When the U-phase is short, the short-circuit point is clamped to the negative bus bar because the lower bridge of the U-phase is normally on, and therefore a loop is formed. When the V-phase is short, the upper and lower bridges of the V-phase do not operate, and thus a circuit is not formed. When the W-phase is short, the W-phase upper bridge is in the PWM state, and thus a loop is formed as shown in fig. 8.
In the state 1, the capacitor Y1 discharges through a W-phase upper bridge and a short place, and the capacitor Y2 charges through a bus capacitor and the W-phase upper bridge and the short place; in the state 2, the capacitor Y2 discharges through a short-point and UW phase winding, and the capacitor Y1 charges through the short-point, the UW phase winding and a bus capacitor; the current added to the winding is therefore made up of two parts, one part being the current resulting from the state 1 bus voltage applied to the winding, as shown in expression (1), and the other part being the current released to the winding by the state 2 capacitor Y1, capacitor Y2.
Therefore, phase 1 can determine if W has a short fault.
Suppose for N1A switching period, the ith switching period is Ts1iThe upper bridge is on with a duty ratio of D1iAnd the lower bridge is normally open. The final winding current is about
In the formula of UdFor bus voltage, L (theta) is series inductance of UW winding, N1Number of pulses, T, co-generated for stage 1s1iFor the ith switching cycle of phase 1, D1iOpening duty cycle for stage 1 upper bridge, CYIs a one-sided Y capacitor.
In stage 2, (the first arm is arm V, i.e., arm 52, and the second arm is arm W, i.e., arm 53), it is assumed that the V-phase upper bridge PWM operation is selected, and the W-phase lower bridge is normally on. The switching states are divided into two types, as shown in fig. 9. When the W phase is short, the W phase lower bridge is normally on, so that the short point is clamped to the negative bus bar, and a loop is formed. When the U-phase is short, the U-phase upper and lower bridges do not operate, and thus a circuit is not formed. When the V-phase is short, the loop is formed because the V-phase upper bridge is in the PWM state, as shown in fig. 9.
In the state 1, the capacitor Y1 discharges through a V-phase upper bridge and a short place, and the capacitor Y2 charges through a bus capacitor and the V-phase upper bridge and the short place; in the state 2, the capacitor Y2 discharges through a short-point and VW phase winding, and the capacitor Y1 charges through the short-point and VW phase winding and a bus capacitor; the current added to the winding is therefore made up of two parts, one part being the current resulting from the state 1 bus voltage applied to the winding, as shown in expression (2), and the other part being the current released to the winding by state 2 capacitor Y1, capacitor Y2.
Stage 2 can therefore determine whether V has a short fault.
Suppose for N2A switching period, the ith switching period is Ts2iThe upper bridge is on with a duty ratio of D2iAnd the lower bridge is normally open. The final winding current is about
In the formula of UdFor bus voltage, L (theta +2 pi/3) is a series inductor of VW winding, N2Number of pulses co-generated for stage 2, Ts2iFor the ith switching cycle of phase 2, D2iOpening duty cycle for stage 2 upper bridge, CYIs a one-sided Y capacitor.
In stage 3, (the first arm is arm U, i.e., arm 51, and the second arm is arm V, i.e., arm 52), it is assumed that U-phase upper bridge PWM operation is selected, and the V-phase lower bridge is normally on. The switching states are divided into two types, as shown in fig. 10. When the V-phase short ground is connected with the bus negative, the V-phase lower bridge is normally on, so that the short ground is clamped to the bus negative, and a loop is formed. When the W-phase is short, the upper and lower bridges of the W-phase do not operate, and thus a circuit is not formed. When the U-phase is short, the U-phase upper bridge is in the PWM state, and thus a loop is formed, as shown in fig. 10.
In the state 1, the capacitor Y1 discharges through a U-phase upper bridge and a short place, and the capacitor Y2 charges through a bus capacitor and the U-phase upper bridge and the short place; in the state 2, the capacitor Y2 discharges through a short point and the UV phase winding, and the capacitor Y1 charges through the short point, the UV phase winding and the bus capacitor; the current added to the winding is therefore made up of two parts, one part being the current resulting from the state 1 bus voltage applied to the winding, as shown in expression (3), and the other part being the current released to the winding by the state 2 capacitor Y1, capacitor Y2.
Suppose for N3A switching period, the ith switching period is T31iThe upper bridge is on with a duty ratio of D3iAnd the lower bridge is normally open. The final winding current is about
In the formula of UdFor bus voltage, L (theta-2 pi/3) is series inductance of UW winding, N3Number of pulses, T, co-generated for stage 3s3iFor the ith switching cycle of phase 3, D3iOpening duty cycle for stage 3 upper bridge, CYIs a one-sided Y capacitor.
Further, the geodesic threshold of the present invention is obtained by:
calculating a second reference current of the motor windings connected in series under a second set condition according to the operating parameters of the motor system in the normal state of the bridge arm group, and generating the short-circuit threshold value based on the second reference current, wherein the second set condition represents that the corresponding phase of the first bridge arm is short-circuited and/or the corresponding phase of the second bridge arm is short-circuited;
wherein the second reference current is calculated by the following equation
Is obtained byDRZRepresenting said second reference current, CYRepresenting the one-sided capacitance magnitude of the safety capacitance.
It will be appreciated that when out of phase, there is no current flow for any duration of the pulse. For example, the phase U is disconnected, and the phase 1 winding and the phase 3 winding do not generate current; the V phase is disconnected, and the windings in the stage 2 and the stage 3 cannot generate current; the W phase is open and no current is generated by the phase 1 and phase 2 windings. For example, any two phases or three phases are absent, and no current exists in the winding at any stage. Therefore, judging whether or not a phase is missing based on the current is a short-circuit threshold setting method of the present invention.
In a specific implementation, as shown in fig. 11, the ordinate is the threshold current and the abscissa is the phase. Phase 1, bus voltage UdThe Hall circuit can be used for sampling the bus voltage; the size of the capacitor Y can be obtained according to the parameters of the whole vehicle; the winding inductance L can be obtained by calculating the motor parameters and the rotation position; the number of pulses, the switching period and the duty ratio of each phase can be set through software. The magnitude of the current generated at each stage is therefore known, as shown by points C1, C2, C3 in fig. 11.
The current calculation error and the Hall sampling error are considered, and a certain margin is reserved. Stage 1 to stage 3 may set the short-ground threshold range as follows
The error values in equations (13), (14), and (15) may be set according to actual conditions.
When the actual winding current is larger than the phase-lack threshold and smaller than the short-earth threshold after the detection of the stage 1, the stage 2, the stage 3 or any two stages, the condition that the phase is not lacked and the short earth is not short is judged; if the actual winding current is smaller than the phase-lack threshold value, judging the phase lack; and judging the short ground if the actual winding current is larger than the short ground threshold value.
If the actual winding current in the phase 1 is larger than the phase-lack threshold and smaller than the short-earth threshold, judging that the UW phase is not phase-lack and the W phase is not short-earth; if the actual winding current is smaller than the phase-lack threshold, judging the phase-lack of the UW phase; and if the actual winding current is larger than the short-ground threshold value, judging that the W phase is short-ground.
If the actual winding current in the stage 2 is larger than the phase-lack threshold and smaller than the short-earth threshold, judging that the VW phase does not lack the phase and the V phase does not have the short-earth; if the actual winding current is smaller than the phase-missing threshold value, judging the VW phase is phase-missing; and if the actual winding current is larger than the short-ground threshold value, judging that the V phase is short-ground.
If the actual winding current in the stage 3 is larger than the phase-lack threshold and smaller than the short-ground threshold, judging that the UV phase does not lack the phase and the U phase does not have the short-ground; if the actual winding current is smaller than the phase-lack threshold value, judging that the UV phase is in phase-lack; and if the actual winding current is larger than the short-ground threshold value, judging that the U phase is short-ground.
Further, in addition to the judgment of whether or not the phase-lack threshold is short based on the current, the present embodiment also proposes to set the phase-lack threshold based on whether or not the pulse judgment is short. In particular, the amount of the solvent to be used,
as shown in fig. 12, the ordinate represents the threshold pulse number, and the abscissa represents the phase. Phase 1, bus voltage UdThe Hall circuit can be used for sampling the bus voltage; the size of the capacitor Y can be obtained according to the parameters of the whole vehicle; the winding inductance L can be obtained by calculating the motor parameters and the rotation position; the switching period, duty cycle, and reference current for each phase may be set by software. The number of pulses generated per phase is therefore known, such as shown by points D1, D2, D3 in fig. 12.
The current calculation error and the Hall sampling error are considered, and a certain margin is reserved. Stage 1 to stage 3 settable threshold ranges are as follows
ND1+σD1<NTD1<NB1-σB1 (16)
ND2+D2<NTD2<NB2-B2 (17)
ND3+D3<NTD3<NB3-B3 (18)
In the formula NB1、NB2、NB3Can be according to the formulas (1) and (2)) And (3) obtaining N by reverse thrustD1、ND2、ND3The error value can be obtained by reverse deduction according to the equations (10), (11) and (12), and the error value can be set according to the actual situation.
When the actual pulse number is larger than the phase-lack threshold value after the detection of the stage 1, the stage 2, the stage 3 or any two stages, the phase-lack is judged; if the actual pulse number is smaller than the short-earth threshold, judging the short earth; and if the actual pulse number is larger than the short-circuit threshold and smaller than the phase-lack threshold, judging whether the phase is not lacked or not.
If the actual pulse number of the stage 1 is larger than the phase-lack threshold, judging the phase-lack of the UW phase; if the actual pulse number is smaller than the short-earth threshold, judging that the W phase is short-earth; and if the actual pulse number is larger than the phase-lack threshold and smaller than the phase-lack threshold, judging that the UW does not lack the phase and does not lack the phase.
If the actual pulse number of the stage 2 is larger than the phase-missing threshold value, judging that the VW phase is phase-missing; if the actual pulse number is smaller than the short-earth threshold value, judging that the V phase is short-earth; and if the actual pulse number is larger than the short-circuit threshold and smaller than the phase-failure threshold, judging that the VW does not have a phase failure and is short.
If the actual pulse number of the stage 3 is larger than the phase-lack threshold, judging that the UV phase is in phase-lack state; if the actual pulse number is smaller than the short-earth threshold, judging that the U phase is short-earth; and if the actual pulse number is larger than the short-circuit threshold and smaller than the phase-defect threshold, judging that the UV does not have the phase defect and is not short.
It can be understood that, referring to fig. 13 in combination with fig. 1b, fig. 13 is a logic block diagram of phase loss and short-circuit detection of an embodiment of a method for detecting a fault of a motor system provided by the present invention, where the motor system is a three-phase motor system, and in each bridge arm group, when the first bridge arm is a W-phase bridge arm, the second bridge arm is a U-phase bridge arm or a V-phase bridge arm; when the first bridge arm is a V-phase bridge arm, the second bridge arm is a W-phase bridge arm or a U-phase bridge arm; when the first bridge arm is a U-phase bridge arm, the second bridge arm is a V-phase bridge arm or a W-phase bridge arm;
the motor system is a three-phase motor system, and in each bridge arm group, when the first bridge arm is a W-phase bridge arm, the second bridge arm is a U-phase bridge arm or a V-phase bridge arm; when the first bridge arm is a V-phase bridge arm, the second bridge arm is a W-phase bridge arm or a U-phase bridge arm; when the first bridge arm is a U-phase bridge arm, the second bridge arm is a V-phase bridge arm or a W-phase bridge arm;
as shown in fig. 13, first, system and motor parameters are acquired, and then a phase loss threshold and a short-earth threshold are calculated. Then, PWM wave is carried out in three stages and the relation between the current and the threshold value is judged. Finally, whether the system is short in phase loss or not can be judged, and the positions of the phase loss and the short place can be identified. The three judging stages are respectively:
stage one: selecting a first bridge arm group of which a first bridge arm is a W-phase bridge arm and a second bridge arm is a U-phase bridge arm, and inputting the preset pulse signal to perform phase-missing judgment and/or short-circuit judgment operation on the first bridge arm group, so that an upper bridge switching tube of the W-phase bridge arm is conducted in a preset mode and a lower bridge switching tube of the U-phase bridge arm is normally conducted;
when the current values of the motor windings connected in series of the W-phase bridge arm and the U-phase bridge arm are smaller than the open-phase threshold value, judging that the corresponding phases of the bridge arm W and/or the bridge arm U are open (open-phase result 1);
and a second stage: selecting a second bridge arm group of which a first bridge arm is a V-phase bridge arm and a second bridge arm is a W-phase bridge arm, and inputting the preset pulse signal to perform phase-missing judgment and/or short-circuit judgment operation on the second bridge arm group, so that an upper bridge switching tube of the V-phase bridge arm is conducted in a preset mode and a lower bridge switching tube of the W-phase bridge arm is normally conducted;
and when the current values of the motor windings connected in series of the V-phase bridge arm and the W-phase bridge arm are smaller than the phase-failure threshold value, judging that the corresponding phases of the V-phase bridge arm and/or the W-phase bridge arm are open-circuited (phase-failure result 2).
And a third stage:
selecting a third bridge arm group of which the first bridge arm is a U-phase bridge arm and the second bridge arm is a V-phase bridge arm, and inputting the preset pulse signal to perform phase-missing judgment and/or short circuit judgment operation on the third bridge arm group, so that an upper bridge switching tube of the U-phase bridge arm is conducted in a preset mode and a lower bridge switching tube of the V-phase bridge arm is normally conducted;
and when the current values of the motor windings connected in series of the U-phase bridge arm and the V-phase bridge arm are smaller than the open-phase threshold value, judging that the corresponding phases of the U-phase bridge arm and/or the V-phase bridge arm are open-circuited (open-phase result 3).
The results of the above three stages are combined into five types:
combination 1: only one of the phase-lack result 1, the phase-lack result 2 and the phase-lack result 3 is satisfied, so that the situation does not exist in the actual working condition;
and (3) combination 2: if the phase-lack result 1 and the phase-lack result 2 are met at the same time, the corresponding phase of the W-phase bridge arm is broken;
and (3) combination: if the phase-lack result 3 and the phase-lack result 2 are met at the same time, the corresponding phase of the V-phase bridge arm is broken;
and (4) combination: if the phase-lack result 1 and the phase-lack result 3 are met at the same time, the corresponding phase of the U-phase bridge arm is broken;
and (3) combination 5: and if the phase-lack result 1, the phase-lack result 2 and the phase-lack result 3 are met, any two phases are disconnected or three phases are disconnected.
In order to solve the above problems, an embodiment of the present invention provides a motor system fault detection device, which may be disposed inside a new energy vehicle, and referring to fig. 14, fig. 14 is a schematic block diagram of the motor system fault detection device.
As shown in fig. 14, the motor system fault detection apparatus includes a processor 1001, namely, an MCU (microcontroller unit), where the processor may be a motor controller inside a new energy vehicle, or may be an independent MCU; a communication bus 1002 for connecting each hardware device; the motor system fault detection apparatus further comprises a memory 1003, and a computer program stored on the memory 1003 and executable on the processor 1001.
Those skilled in the art will appreciate that the configuration shown in fig. 14 does not constitute a limitation of the motor system failure detection apparatus and may include more or fewer components than shown, or some components in combination, or a different arrangement of components.
As shown in fig. 14, the memory 1003, which is a kind of computer storage medium, may include therein an operating system and a computer program configured to implement the steps of the motor system fault detection method.
Furthermore, to achieve the above object, the present invention further provides a computer readable storage medium, having a computer program stored thereon, which, when being executed by a processor, implements the steps of the motor system fault detection method as described above.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system 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 system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.
Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number, or order, of the technical features indicated. In the description of the present invention, the terms "plurality" and "a plurality" mean two (two strips) or more than two (two strips) unless otherwise specified.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the present specification and drawings, or used directly or indirectly in other related fields, are included in the scope of the present invention.
Claims (13)
1. A fault detection method for a motor system comprises an inverter and a motor; the inverter comprises n bridge arms, each bridge arm comprises an upper bridge switching tube and a lower bridge switching tube, the motor comprises n motor windings, the n motor windings are connected with the n bridge arms in a one-to-one correspondence mode, n is a positive integer, the method is characterized by being executed in the motor shutdown state, and the method comprises the following steps:
selecting an upper bridge switching tube of any one or more bridge arms, inputting a preset pulse signal to the selected upper bridge switching tube to enable the selected upper bridge switching tube to be switched on and off according to a preset mode, selecting a lower bridge switching tube of one or more bridge arms in the rest bridge arms, inputting a preset pulse signal to the selected lower bridge switching tube to enable the selected lower bridge switching tube to be kept on according to the preset mode, and circulating n switching cycles;
and detecting the current flowing through the selected bridge arm, comparing the current with a preset current open-phase threshold value, and judging whether the current is open-phase or not.
2. The method of claim 1, wherein in case of determining phase loss, determining whether short-circuit occurs is performed according to a comparison between the detected current and a preset current short-circuit threshold.
3. The method of claim 2, wherein the current open-phase threshold is non-overlapping with the current short-earth threshold range; when the detected current is smaller than the current open-phase threshold value, judging that the current is open-phase; when the detected current is larger than the current open-phase threshold and smaller than the current short-ground threshold, judging that the open phase does not generate short ground; and when the detected current is larger than the current short-ground threshold value, judging as short ground.
4. The method of claim 3, wherein the current open-phase threshold is calculated by the following equation:
wherein, IRZIndicating the current open-phase threshold, UdRepresenting bus voltage, L representing motor winding inductance, N representing number of pulses, TsiDenotes the ith switching cycle, DiSwitch tube for indicating upper bridgeOn duty cycle of (d).
5. The method of claim 4, wherein the current open-phase threshold is adjusted according to a current calculation error and a Hall sampling error, and the current open-phase threshold ranges from:
wherein, IRZIndicating the current open-phase threshold, UdRepresenting bus voltage, L representing motor winding inductance, N representing number of pulses, TsiDenotes the ith switching cycle, DiRepresents the turn-on duty ratio of the upper bridge switching tube,A、A1and error values representing current calculation errors and Hall sampling errors.
6. The method of claim 3 or 4, wherein the current short-earth threshold is calculated by the following equation:
wherein, IDRZRepresenting the current short-earth threshold, CYRepresenting the one-sided capacitance magnitude of the safety capacitance.
7. The method according to claim 3 or 4, wherein the current short-earth threshold is adjusted according to a current calculation error and a Hall sampling error, and the current open-phase threshold ranges from:
wherein IDRZ represents the current short-ground threshold, CY represents the one-sided capacitance size of the safety capacitor,A、A1and error values representing current calculation errors and Hall sampling errors.
8. A fault detection method for a motor system comprises an inverter and a motor; the inverter comprises n bridge arms, each bridge arm comprises an upper bridge switching tube and a lower bridge switching tube, the motor comprises n motor windings, the n motor windings are connected with the n bridge arms in a one-to-one correspondence mode, n is a positive integer, the method is characterized by being executed in the motor shutdown state, and the method comprises the following steps:
selecting an upper bridge switching tube of any one or more bridge arms, inputting a preset pulse signal to the selected upper bridge switching tube to enable the selected upper bridge switching tube to be switched on and off according to a preset mode, selecting a lower bridge switching tube of one or more bridge arms in the rest bridge arms, inputting a preset pulse signal to the selected lower bridge switching tube to enable the selected lower bridge switching tube to be kept on according to the preset mode, and circulating n switching cycles;
and detecting the pulse frequency of the selected bridge arm, comparing the pulse frequency with a preset pulse open-phase threshold value, and judging whether the phase is open.
9. The method according to claim 8, wherein in the case of determining phase loss, whether the phase is short is determined according to the comparison between the detected number of pulses and a preset pulse short threshold.
10. The method of claim 9, wherein the pulse open phase threshold is non-overlapping with the pulse short ground threshold range; when the detected pulse frequency is greater than the pulse open-phase threshold, judging that the pulse is open-phase; when the detected pulse frequency is smaller than the pulse phase-missing threshold and larger than the pulse short-ground threshold, judging that no phase-missing occurs and no short ground occurs; and when the detected pulse frequency is less than the pulse short-ground threshold value, judging the pulse is short-ground.
11. The method according to claim 10, wherein the pulse open-phase threshold or the pulse short-ground threshold is obtained by reading the number of pulses as a reference when the motor system is operated in a normal state, and adjusting the reference range according to a current calculation error and a Hall sampling error.
12. An electric machine system short-circuit detection apparatus, characterized by comprising a memory and a processor, the memory having stored therein a computer program operable on the processor, the processor implementing the steps of the electric machine system fault detection method according to any one of claims 1 to 11 when executing the computer program.
13. A computer-readable storage medium, characterized in that a computer program is stored thereon, which computer program, when being executed by a processor, carries out the steps of the method of motor system fault detection according to any one of claims 1 to 11.
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| CN113985177A (en) * | 2021-10-29 | 2022-01-28 | 江铃汽车股份有限公司 | Method and device for quickly diagnosing 48V system fault of hybrid electric vehicle |
| CN117491756A (en) * | 2023-12-29 | 2024-02-02 | 深圳麦格米特电气股份有限公司 | Phase failure detection method, training method of phase failure detection network model and related device |
| CN117595750A (en) * | 2024-01-19 | 2024-02-23 | 黑龙江惠达科技股份有限公司 | Electrical adjustment self-checking method and system for electric motor of spreader |
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| CN117595750A (en) * | 2024-01-19 | 2024-02-23 | 黑龙江惠达科技股份有限公司 | Electrical adjustment self-checking method and system for electric motor of spreader |
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