CN111130429A - Power conversion device and power conversion system - Google Patents
Power conversion device and power conversion system Download PDFInfo
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- CN111130429A CN111130429A CN201911034953.9A CN201911034953A CN111130429A CN 111130429 A CN111130429 A CN 111130429A CN 201911034953 A CN201911034953 A CN 201911034953A CN 111130429 A CN111130429 A CN 111130429A
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- phase
- power conversion
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- determination
- voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/028—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the motor continuing operation despite the fault condition, e.g. eliminating, compensating for or remedying the fault
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/025—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the fault being a power interruption
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/027—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the fault being an over-current
Abstract
Provided are a power conversion device and a power conversion system that determine which of three-phase power systems has an abnormality. The control unit (50) performs voltage determination and current determination for each of the 6 switching elements (Q1-Q6), determines whether or not the source-drain voltages predetermined as determination targets among the source-drain voltages of the 6 switching elements (Q1-Q6) are abnormal, and determines whether or not the phase current predetermined as determination targets among the 3 phase currents flowing through the power conversion circuit (20) and the motor (100) is abnormal. The control unit (50) detects an abnormal power system from a three-phase power system including the power conversion circuit (20) and the motor (100) on the basis of the voltage determination result and the current determination result obtained for each of the 6 switching modes of the switching elements (Q1-Q6).
Description
Technical Field
The technology disclosed herein relates to a power conversion apparatus.
Background
Power conversion devices are used in various technical fields. For example, patent document 1 discloses a 2-series motor control device. The 1 st series and the 2 nd series of the motor control device respectively have: a drive circuit for driving the motor; 3 phase open relays provided at connection lines of each phase between the motor and the drive circuit, for switching on and off of current from the drive circuit to the motor by turning on and off; and a control unit that controls switching between on and off of the phase open relay.
Patent document 1: japanese patent laid-open publication No. 2017-118651
In the power conversion device as disclosed in patent document 1, it is not possible to specify which of the three-phase power systems including the power conversion circuit and the motor has an abnormality.
Disclosure of Invention
The technology disclosed herein relates to a power conversion device that supplies power to a three-phase ac motor. The power conversion device includes: a power conversion circuit having 6 switching elements connected in a three-phase bridge, the power conversion circuit converting input power into output power of three-phase alternating current by switching operations of the 6 switching elements; and a control unit that performs voltage determination and current determination for each of the 6 switching elements in each of the switching modes, determines whether or not a source-drain voltage predetermined as a determination target in the switching mode among source-drain voltages of the 6 switching elements is abnormal, and determines whether or not a phase current predetermined as the determination target in the switching mode among 3 phase currents flowing through the power conversion circuit and the motor is abnormal in the current determination, wherein the control unit detects an abnormal power system from among three-phase power systems configured by the power conversion circuit and the motor, based on a result of the voltage determination and a result of the current determination obtained in each of the 6 switching elements.
According to the technology disclosed herein, it is possible to determine which of the three-phase power systems constituted by the power conversion circuit and the motor has an abnormality.
Drawings
Fig. 1 is a block diagram illustrating a configuration of a power conversion device of an embodiment.
Fig. 2 is a diagram illustrating a relationship among the switching pattern, the detection target, and the determination target in the short-circuit abnormality determination process.
Fig. 3 is a diagram illustrating a relationship among the switching pattern, the detection target, and the determination target in the short-circuit abnormality determination process.
Fig. 4 is a diagram illustrating a relationship among the determination result of the short-circuit abnormality determination process, the abnormality system, and the control process.
Fig. 5 is a diagram illustrating a relationship among the switching pattern, the detection target, and the determination target in the open circuit abnormality determination processing.
Fig. 6 is a diagram illustrating a relationship among the switching pattern, the detection target, and the determination target in the open circuit abnormality determination processing.
Fig. 7 is a diagram illustrating a relationship among the determination result of the open circuit abnormality determination process, the abnormality system, and the control process.
Fig. 8 is a block diagram illustrating the structure of a power conversion system having a power conversion device.
Description of the reference symbols
1: a power conversion system; 10: a power conversion device; 11: a 1 st input line; 12: a 2 nd input line; 13: a smoothing capacitor; 20: a power conversion circuit; 31: a phase voltage detection unit; 31 u: a U-phase voltage detection unit; 31 v: a V-phase voltage detection unit; 31 w: a W-phase voltage detection unit; 32: a phase current detection unit; 32 u: a U-phase current detection unit; 32 v: a V-phase current detection unit; 32 w: a W-phase current detection unit; 40: a drive circuit; 50: a control unit; 100: a motor; Q1-Q6: a switching element.
Detailed Description
Hereinafter, embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.
(Power conversion device)
Fig. 1 illustrates a structure of a power conversion device 10 of the embodiment. The power converter 10 supplies power to a three-phase ac motor 100. The power conversion device 10 includes a 1 st input line 11, a 2 nd input line 12, a smoothing capacitor 13, a power conversion circuit 20, 3 connection lines 21, 3 switches 22, 3 phase voltage detection units 31, 3 phase current detection units 32, a drive circuit 40, and a control unit 50.
[ input line and smoothing capacitor ]
The 1 st input line 11 and the 2 nd input line 12 provide input power to the power conversion circuit 20. In this example, the 1 st input line 11 is connected to the positive electrode of a battery (not shown) and is supplied with the power supply voltage VB. The 2 nd input line 12 is connected to the negative electrode of the battery and is applied with the ground voltage VG. The smoothing capacitor 13 is connected between the 1 st input line 11 and the 2 nd input line 12.
[ Power conversion Circuit ]
The power conversion circuit 20 includes 6 switching elements Q1 to Q6 connected in a three-phase bridge, and converts input power into output power of three-phase ac by switching operations of the 6 switching elements Q1 to Q6. The switching elements Q1 to Q6 are each formed of a transistor such as an FET. The 6 switching elements Q1 to Q6 are the 1 st switching element Q1, the 2 nd switching element Q2, the 3 rd switching element Q3, the 4 th switching element Q4, the 5 th switching element Q5, and the 6 th switching element Q6.
[ connecting line ]
The 3 connection lines 21 connect the power conversion circuit 20 and the motor 100. The 3 connection lines 21 are a U-phase connection line 21U corresponding to U of the motor 100, a V-phase connection line 21V corresponding to V of the motor 100, and a W-phase connection line 21W corresponding to W of the motor 100. In the power conversion circuit 20, the 1 st switching element Q1 is connected between the 1 st input line 11 and the U-phase connection line 21U. The 2 nd switching element Q2 is connected between the 1 st input line 11 and the V-phase connection line 21V. The 3 rd switching element Q3 is connected between the 1 st input line 11 and the W-phase connection line 21W. The 4 th switching element Q4 is connected between the U-phase connection line 21U and the 2 nd input line 12. The 5 th switching element Q5 is connected between the V-phase connection line 21V and the 2 nd input line 12. The 6 th switching element Q6 is connected between the W-phase connection line 21W and the 2 nd input line 12.
[ switch ]
The 3 switches 22 are respectively disposed on the 3 connection lines 21. The switch 22 can be switched to an on state in which power is transmitted and an off state in which power transmission is cut off. The 3 switches 22 are a U-phase switch 22U provided on the U-phase connection line 21U, a V-phase switch 22V provided on the V-phase connection line 21V, and a W-phase switch 22W provided on the W-phase connection line 21W.
[ phase voltage detection unit ]
The 3-phase voltage detection unit 31 detects 3-phase voltages Vu, Vv, Vw applied to the 3 connection lines 21, respectively. The phase voltage detection unit 31 is formed of, for example, a resistance element. The 3-phase voltage detection unit 31 is a U-phase voltage detection unit 31U that detects a U-phase voltage Vu, a V-phase voltage detection unit 31V that detects a V-phase voltage Vv, and a W-phase voltage detection unit 31W that detects a W-phase voltage Vw. The detection signals of the 3-phase voltage detection unit 31 are input to the drive circuit 40 and the control unit 50.
[ phase current detection section ]
The 3-phase current detection unit 32 detects 3-phase currents iu, iv, and iw flowing through the power conversion circuit 20 and the motor 100, respectively. The phase current detection unit 32 is constituted by, for example, a shunt resistor. The 3-phase current detecting unit 32 is a U-phase current detecting unit 32U that detects the U-phase current iu, a V-phase current detecting unit 32V that detects the V-phase current iv, and a W-phase current detecting unit 32W that detects the W-phase current iw. The detection signal of the 3-phase current detection unit 32 is input to the control unit 50.
[ drive Circuit ]
The drive circuit 40 controls switching operations of the 6 switching elements Q1 to Q6. In this example, the drive circuit 40 controls the switching operation of the 6 switching elements Q1 to Q6 in response to the control of the control unit 50. Specifically, the drive circuit 40 supplies control signals for controlling on and off to the 6 switching elements Q1 to Q6, respectively, and controls the switching operation of the 6 switching elements Q1 to Q6 by changing the levels of the control signals supplied to the 6 switching elements Q1 to Q6, respectively. In this example, each of the 6 switching elements Q1 to Q6 is turned on when the level of the control signal is high, and is turned off when the level of the control signal is low. The drive circuit 40 is configured by a combination of logic elements, for example.
The drive circuit 40 has a protection function for protecting the 6 switching elements Q1 to Q6 from the short-circuit abnormality. Specifically, when detecting a source-drain voltage lower than a predetermined protection voltage threshold from among the source-drain voltages of the 6 switching elements Q1 to Q6, the drive circuit 40 turns off the switching element corresponding to the source-drain voltage lower than the protection voltage threshold from among the 6 switching elements Q1 to Q6.
[ control section ]
The controller 50 controls the drive circuit 40 to control the switching operation of the 6 switching elements Q1 to Q6 of the power conversion circuit 20. The control unit 50 controls on and off of the 3 switches 21.
In this example, the control unit 50 performs an abnormality detection process. In the abnormality detection process, the control unit 50 performs voltage determination and current determination for each of the 6 switching modes of the switching elements Q1 to Q6. In the voltage determination for each of the switching modes of the switching elements Q1 to Q6, the control unit 50 determines whether or not the source-drain voltage determined in advance as a determination target in the switching mode among the source-drain voltages of the 6 switching elements Q1 to Q6 is abnormal. In the current determination for each of the switching modes of the switching elements Q1 to Q6, the control unit 50 determines whether or not the phase current predetermined as the determination target in the switching mode is abnormal among the 3 phase currents iu, iv, iw flowing through the power conversion circuit 20 and the motor 100. Then, the control unit 50 detects an abnormal power system from among the three-phase power systems including the power conversion circuit 20 and the motor 100, based on the voltage determination result and the current determination result obtained for each of the switching modes of the 6 switching elements Q1 to Q6.
In this example, the control unit 50 turns off the switch 22 corresponding to the power system in which the abnormality occurs among the 3 switches 22. Specifically, the control unit 50 changes the switch 22 corresponding to the power system in which the abnormality occurs among the 3 switches 22 from the on state to the off state, and continuously maintains the switch 22 corresponding to the power system in which the abnormality does not occur among the 3 switches 22 in the on state.
In this example, the controller 50 detects the switching patterns of the switching elements Q1 to Q6, for example, based on the levels of control signals supplied to the switching elements Q1 to Q6, and commands output from the controller 50 to the drive circuit 40 to control the switching operations of the switching elements Q1 to Q6.
< details of abnormality detection processing >
In this example, the control unit 50 performs short-circuit abnormality detection processing and open-circuit abnormality detection processing as abnormality detection processing. In the following description, a short-circuit fault of the winding of the motor 100 or the switching element of the power conversion circuit 20 refers to a state in which the winding of the motor 100 or the switching element of the power conversion circuit 20 is short-circuited. The open failure of the winding of the motor 100 or the switching element of the power conversion circuit 20 means that the winding of the motor 100 or the switching element of the power conversion circuit 20 is disconnected. The short-circuit abnormality of the power system refers to a state in which the power system becomes abnormal due to a short-circuit failure of the winding of the motor 100 or the switching elements of the power conversion circuit 20. The open circuit abnormality of the power system refers to a state in which the power system becomes abnormal due to an open failure of the winding of the motor 100 or the switching elements of the power conversion circuit 20.
Short circuit abnormality detection/processing
In the short-circuit abnormality detection process, when the source-drain voltage to be determined among the source-drain voltages of the 6 switching elements Q1 to Q6 is lower than a predetermined normal voltage threshold in the voltage determination, the control unit 50 determines that the source-drain voltage is abnormal. In the current determination, when the phase current to be determined among the 3 phase currents iu, iv, iw flowing through the power conversion circuit 20 and the motor 100 is higher than a predetermined high current threshold value, the control unit 50 determines that the phase current is a high current abnormality. Then, the control unit 50 detects an electric power system in which a short-circuit abnormality occurs from among three-phase electric power systems including the electric power conversion circuit 20 and the motor 100, based on a combination of a result of voltage determination indicating a source-drain voltage abnormality and a result of current determination indicating a high-current abnormality, among combinations of a result of voltage determination and a result of current determination obtained for each of the 6 switching elements Q1 to Q6.
The normal voltage threshold is set to, for example, the minimum value of the source-drain voltage that can be considered as a normal source-drain voltage. The high current threshold is set to, for example, the maximum value of the phase current that can be regarded as the case where the phase current is normal.
In addition, in this example, the normal voltage threshold is higher than the protection voltage threshold. As described above, the protection voltage threshold is a threshold as a reference for determining whether or not the switching element should be forcibly turned off in the drive circuit 40.
< open-Circuit abnormality detection processing >
In the open circuit abnormality detection process, when the source-drain voltage to be determined among the source-drain voltages of the 6 switching elements Q1 to Q6 is lower than a predetermined normal voltage threshold in the voltage determination, the control unit 50 determines that the source-drain voltage is abnormal. In the current determination, when the phase current to be determined among the 3 phase currents iu, iv, iw flowing through the power conversion circuit 20 and the motor 100 is lower than a predetermined low current threshold value, the control unit 50 determines that the phase current is a low current abnormality. Then, the control unit 50 detects an electric power system in which an open circuit abnormality occurs from among three-phase electric power systems including the electric power conversion circuit 20 and the motor 100, based on a combination of a result of voltage determination indicating a source-drain voltage abnormality and a result of current determination indicating a low-current abnormality, among combinations of a result of voltage determination and a result of current determination obtained for each of the 6 switching elements Q1 to Q6.
The low current threshold is set to, for example, a minimum value of the phase current that can be regarded as a case where the phase current is normal.
[ correlation of abnormality ]
Here, the relationship between an abnormality in the three-phase power system including the power conversion circuit 20 and the motor 100 and an abnormality in the source-drain voltages of the 6 switching elements Q1 to Q6 and an abnormality in the 3 phase currents iu, iv, iw in the specific switching pattern of the switching elements Q1 to Q6 will be described.
Hereinafter, the source-drain voltage of the 1 st switching element Q1 is referred to as a "1 st source-drain voltage VQ 1", the source-drain voltage of the 2 nd switching element Q2 is referred to as a "2 nd source-drain voltage VQ 2", the source-drain voltage of the 3 rd switching element Q3 is referred to as a "3 rd source-drain voltage VQ 3", the source-drain voltage of the 4 th switching element Q4 is referred to as a "4 th source-drain voltage VQ 4", the source-drain voltage of the 5 th switching element Q5 is referred to as a "5 th source-drain voltage VQ 5", and the source-drain voltage of the 6 th switching element Q6 is referred to as a "6 th source-drain voltage VQ 6".
The 1 st source-drain voltage VQ1 corresponds to the difference between the power supply voltage VB applied to the 1 st input line 11 and the U-phase voltage Vu applied to the U-phase connection line 21U. The 2 nd source-drain voltage VQ2 corresponds to the difference between the power supply voltage VB applied to the 1 st input line 11 and the V-phase voltage Vv applied to the V-phase connection line 21V. The 3 rd source-drain voltage VQ3 corresponds to the difference between the power supply voltage VB applied to the 1 st input line 11 and the W-phase voltage Vw applied to the W-phase connection line 21W.
The 4 th source-drain voltage VQ4 corresponds to the difference between the U-phase voltage Vu applied to the U-phase connection line 21U and the ground voltage VG applied to the 2 nd input line 12. The 5 th source-drain voltage VQ5 corresponds to the difference between the V-phase voltage Vv applied to the V-phase connection line 21V and the ground voltage VG applied to the 2 nd input line 12. The 6 th source-drain voltage VQ6 corresponds to the difference between the W-phase voltage Vw applied to the W-phase connection line 21W and the ground voltage VG applied to the 2 nd input line 12.
As a result of intensive studies, the inventors of the present application have found the following. That is, there is a correlation between an abnormality in the three-phase power system constituted by the power conversion circuit 20 and the motor 100, and an abnormality in the 6 source-drain voltages VQ1 to VQ6 and an abnormality in the 3-phase currents iu, iv, iw in the specific switching pattern of the switching elements Q1 to Q6. Therefore, it is possible to detect the power system in which the abnormality occurs from the three-phase power system including the power conversion circuit 20 and the motor 100, based on the presence or absence of the abnormality in the 6 source-drain voltages VQ1 to VQ6 and the presence or absence of the abnormality in the 3-phase currents iu, iv, and iw in the specific switching pattern of the switching elements Q1 to Q6.
< short-circuit abnormality of electric power system caused by short-circuit failure of winding >
For example, when a short-circuit fault occurs in the U-phase winding of the motor 100 and a short-circuit abnormality occurs in the U-phase power system, the following 4 switching patterns are characteristic.
(1) In the switching mode in which the 3 rd, 4 th switching elements Q3, Q4 are in the on state and the 1 st, 2 nd, 5 th, 6 th switching elements Q1, Q2, Q5, Q6 are in the off state, the 3 rd, 4 th inter-source-drain voltages VQ3, VQ4 are respectively lower than the normal voltage threshold, and the U-phase current iu is higher than the high current threshold.
(2) In the switching mode in which the 2 nd, 4 th switching elements Q2, Q4 are in the on state and the 1 st, 3 rd, 5 th, 6 th switching elements Q1, Q3, Q5, Q6 are in the off state, the 2 nd, 4 th inter-source-drain voltages VQ2, VQ4 are respectively lower than the normal voltage threshold, and the U-phase current iu is higher than the high current threshold.
(3) In a switching mode in which the 1 st, 6 th switching elements Q1, Q6 are in an on state and the 2 nd, 3 rd, 4 th, 5 th switching elements Q2, Q3, Q4, Q5 are in an off state, the 1 st, 6 th inter-source-drain voltages VQ1, VQ6 are respectively lower than a normal voltage threshold, and the phase current iu is higher than a high current threshold.
(4) In a switching mode in which the 1 st, 5 th switching elements Q1, Q5 are in an on state and the 2 nd, 3 rd, 4 th, 6 th switching elements Q2, Q3, Q4, Q6 are in an off state, the 1 st, 5 th inter-source-drain voltages VQ1, VQ5 are respectively lower than a normal voltage threshold, and the phase current iu is higher than a high current threshold.
Therefore, based on the presence or absence of an abnormality in the source-drain voltage and the presence or absence of an abnormality in the phase current in each of the 4 switching patterns, it is possible to detect a short-circuit abnormality in the U-phase power system caused by a short-circuit failure in the U-phase winding of the motor 100.
< short-circuit abnormality of electric power system caused by short-circuit failure of switching element >
For example, when a short-circuit fault occurs in the 4 th switching element Q4 of the power conversion circuit 20 and a short-circuit abnormality occurs in the U-phase power system, the following 2 switching patterns are characterized.
(1) In the switching mode in which the 1 st and 6 th switching elements Q1 and Q6 are in the on state and the 2 nd, 3 rd, 4 th and 5 th switching elements Q2, Q3, Q4 and Q5 are in the off state, the 1 st and 6 th inter-source-drain voltages VQ1 and VQ6 are respectively lower than the normal voltage threshold value, while the phase current iu is not higher than the high current threshold value.
(2) In the switching mode in which the 1 st and 5 th switching elements Q1 and Q5 are in the on state and the 2 nd, 3 rd, 4 th and 6 th switching elements Q2, Q3, Q4 and Q6 are in the off state, the 1 st and 5 th inter-source-drain voltages VQ1 and VQ5 are respectively lower than the normal voltage threshold value, while the phase current iu is not higher than the high current threshold value.
Therefore, it is possible to detect a short-circuit abnormality of the U-phase power system caused by a short-circuit failure of the 4 th switching element Q4 of the power conversion circuit 20 based on the presence or absence of an abnormality in the source-drain voltage and the presence or absence of an abnormality in the phase current in each of the 2 switching patterns described above.
< open circuit abnormality of electric power system caused by open circuit fault of winding >
For example, when an open-circuit fault occurs in the U-phase winding of the motor 100 and an open-circuit abnormality occurs in the U-phase power system, the following 4 switching patterns are characterized.
(1) In the switching mode in which the 3 rd, 4 th switching elements Q3, Q4 are in the on state and the 1 st, 2 nd, 5 th, 6 th switching elements Q1, Q2, Q5, Q6 are in the off state, the 3 rd, 4 th inter-source-drain voltages VQ3, VQ4 are respectively lower than the normal voltage threshold, and the U-phase current iu is lower than the low current threshold.
(2) In the switching mode in which the 2 nd, 4 th switching elements Q2, Q4 are in the on state and the 1 st, 3 rd, 5 th, 6 th switching elements Q1, Q3, Q5, Q6 are in the off state, the 2 nd, 4 th inter-source-drain voltages VQ2, VQ4 are respectively lower than the normal voltage threshold, and the U-phase current iu is lower than the low current threshold.
(3) In a switching mode in which the 1 st, 6 th switching elements Q1, Q6 are in an on state and the 2 nd, 3 rd, 4 th, 5 th switching elements Q2, Q3, Q4, Q5 are in an off state, the 1 st, 6 th inter-source-drain voltages VQ1, VQ6 are respectively lower than a normal voltage threshold, and the phase current iu is lower than a low current threshold.
(4) In a switching mode in which the 1 st, 5 th switching elements Q1, Q5 are in an on state and the 2 nd, 3 rd, 4 th, 6 th switching elements Q2, Q3, Q4, Q6 are in an off state, the 1 st, 5 th inter-source-drain voltages VQ1, VQ5 are respectively lower than a normal voltage threshold, and the phase current iu is lower than a low current threshold.
Therefore, it is possible to detect an open circuit abnormality of the U-phase power system caused by an open circuit failure of the U-phase winding of the motor 100 based on the presence or absence of an abnormality of the source-drain voltage and the presence or absence of an abnormality of the phase current in each of the 4 switching patterns described above.
< open circuit abnormality of electric power system caused by open circuit failure of switching element >
For example, when an open failure occurs in the 4 th switching element Q4 of the power conversion circuit 20 and an open circuit abnormality occurs in the U-phase power system, the following 2 switching patterns are characterized.
(1) In a switching mode in which the 1 st, 6 th switching elements Q1, Q6 are in an on state and the 2 nd, 3 rd, 4 th, 5 th switching elements Q2, Q3, Q4, Q5 are in an off state, the 1 st, 6 th inter-source-drain voltages VQ1, VQ6 are respectively lower than a normal voltage threshold, and the phase current iu is lower than a low current threshold.
(2) In the switching mode in which the 1 st, 5 th switching elements Q1, Q5 are in the on state and the 2 nd, 3 rd, 4 th, 6 th switching elements Q2, Q3, Q4, Q6 are in the off state, the 1 st, 5 th inter-source-drain voltages VQ1, VQ5 are respectively lower than the normal voltage threshold, and the phase current iu is lower than the low current threshold.
Therefore, it is possible to detect an open circuit abnormality of the U-phase power system caused by an open circuit failure of the 4 th switching element Q4 of the power conversion circuit 20 based on the presence or absence of an abnormality in the source-drain voltage and the presence or absence of an abnormality in the phase current in each of the 2 switching modes described above.
[ short-circuit abnormality determination processing and short-circuit abnormality determination processing ]
The present inventors have also found that a power system in which a short-circuit abnormality has occurred can be detected from a three-phase power system including the power conversion circuit 20 and the motor 100 by sequentially performing the 1 st to 24 th short-circuit abnormality determination processes shown in fig. 2 and 3 and performing the short-circuit abnormality determination process based on the correspondence relationship shown in fig. 4.
In this example, the control unit 50 sequentially performs 1 st to 24 th short-circuit abnormality determination processes shown in fig. 2 and 3, and performs a short-circuit abnormality determination process according to the correspondence relationship shown in fig. 4. The short-circuit abnormality determination processing and the short-circuit abnormality specification processing are examples of short-circuit abnormality detection processing.
< short-circuit abnormality determination processing >
Fig. 2 and 3 show the contents of the 1 st to 24 th short-circuit abnormality determination processes. In fig. 2 and 3, "No." indicates the number of the short-circuit abnormality determination process, "H" indicates that the switching element is in the on state, and "L" indicates that the switching element is in the off state. The circular mark indicates that it is a detection object, and the x mark indicates that it is not a detection object.
As shown in fig. 2 and 3, in the 1 st to 24 th short-circuit abnormality determination processes, the switching patterns of the switching elements Q1 to Q6 as the objects of the short-circuit abnormality determination process, the phase voltage and the phase current as the objects of detection in the switching patterns, and the source-drain voltage and the phase current as the objects of determination in the switching patterns are determined in advance, respectively. For example, in the 1 st short-circuit abnormality determination process, a switching pattern in which the 3 rd, 4 th switching elements Q3, Q4 are in an on state and the 1 st, 2 nd, 5 th, 6 th switching elements Q1, Q2, Q5, Q6 are in an off state is a target of processing, the U-phase voltage Vu, the W-phase voltage Vw, and the U-phase current iu in the switching pattern are targets of detection, the 3 rd, 4 th source-drain voltages VQ3, VQ4 in the switching pattern are targets of voltage determination, and the U-phase current iu in the switching pattern is a target of current comparison.
In this example, in the short-circuit abnormality determination processing shown in fig. 2 and 3, switching elements to be determined whether or not the switching elements are turned off by the protection function of the drive circuit 40 are determined in advance. For example, in the 1 st short-circuit abnormality determination process, the 3 rd and 4 th switching elements Q3 and Q4 are targets of determination as to whether or not the off state is set by the protection function of the drive circuit 40.
The 1 st to 4 th short-circuit abnormality determination processes shown in fig. 2 are processes for detecting a short-circuit abnormality of the U-phase power system caused by a short-circuit fault in the U-phase winding of the motor 100. The 5 th to 8 th short-circuit abnormality determination processes shown in fig. 2 are processes for detecting a short-circuit abnormality of the V-phase power system caused by a short-circuit fault of the V-phase winding of the motor 100. The 9 th to 12 th short-circuit abnormality determination processes shown in the 9 th to 12 th stages of the example of fig. 2 are processes for detecting a short-circuit abnormality of the W-phase power system caused by a short-circuit fault of the W-phase winding of the motor 100.
In addition, the 13 th and 14 th short-circuit abnormality determination processes shown in fig. 3 are processes for detecting a short-circuit abnormality of the U-phase power system caused by a short-circuit fault of the 4 th switching element Q4 of the power conversion circuit 20. The 15 th and 16 th short-circuit abnormality determination processes shown in fig. 3 are processes for detecting a short-circuit abnormality of the V-phase power system caused by a short-circuit fault of the 5 th switching element Q5 of the power conversion circuit 20. The 17 th and 18 th short-circuit abnormality determination processes shown in fig. 3 are processes for detecting a short-circuit abnormality of the W-phase electric power system caused by a short-circuit fault of the 6 th switching element Q6 of the electric power conversion circuit 20.
The 19 th and 20 th short-circuit abnormality determination processes shown in fig. 3 are processes for detecting a short-circuit abnormality of the U-phase power system caused by a short-circuit fault of the 1 st switching element Q1 of the power conversion circuit 20. The 21 st and 22 nd short-circuit abnormality determination processes shown in fig. 3 are processes for detecting a short-circuit abnormality of the V-phase power system caused by a short-circuit fault of the 2 nd switching element Q2 of the power conversion circuit 20. The 23 rd and 24 th short-circuit abnormality determination processes shown in fig. 3 are processes for detecting a short-circuit abnormality of the W-phase electric power system caused by a short-circuit fault of the 3 rd switching element Q3 of the electric power conversion circuit 20.
< short-circuit abnormality determination processing by control section >
In this example, the control unit 50 performs the following operations in each of the 1 st to 24 th short-circuit abnormality determination processes. In the following, an operation in the kth short-circuit abnormality determination process will be described as an example. k is an integer of 1 or more and 24 or less.
First, when the switching patterns of the switching elements Q1 to Q6 are set to the switching patterns predetermined for the kth short-circuit abnormality determination process, the control unit 50 detects the phase voltage and the phase current predetermined as the detection target in the kth short-circuit abnormality determination process, among the 3 phase voltages Vu, Vv, Vw and the 3 phase currents iu, iv, iw. The detected phase current is a phase current that is determined in advance as a determination target in the kth short-circuit abnormality determination process.
Next, the control unit 50 derives source-drain voltages predetermined as determination targets in the kth short-circuit abnormality determination process among the 6 source-drain voltages VQ1 to VQ6, from the detected phase voltage, the power supply voltage VB applied to the 1 st input line 11, and the ground voltage VG applied to the 2 nd input line 12. The derived source-drain voltage is a source-drain voltage predetermined as a determination target in the kth short-circuit abnormality determination process.
Then, the control unit 50 determines the voltage of the derived source-drain voltage. In this voltage determination, the control unit 50 compares the derived source-drain voltage with a normal voltage threshold, and determines that the source-drain voltage is abnormal when the source-drain voltage is lower than the normal voltage.
Further, the control unit 50 performs current determination on the detected phase current. In the current determination, the control unit 50 compares the detected phase current with a high current threshold value, and determines that the phase current is a high current abnormality when the phase current is higher than the high current threshold value.
In this example, the control unit 50 performs protection determination on the switching element predetermined as the determination target in the kth short-circuit abnormality determination process. In the protection determination, the control unit 50 determines whether or not the switching element to be determined is turned off by the protection function of the drive circuit 40, and determines that the switching element is in the protection state when the switching element is turned off by the drive circuit 40.
As described above, the 1 st to 24 th short circuit abnormality determination processes are sequentially performed. The determination result of the short-circuit abnormality determination process includes a result of voltage determination, a result of current determination, and a result of protection determination. That is, the determination result of the short-circuit abnormality determination process is a combination of the result of the voltage determination, the result of the current determination, and the result of the protection determination, which are obtained in the specific switching mode of the switching elements Q1 to Q6.
< short-circuit abnormality determination processing >
Fig. 4 shows a correspondence relationship between a combination of determination results of the short-circuit abnormality determination processing, an abnormal system that is an electric power system considered to have a short-circuit abnormality, and the switch 22 that should be put into an off state among the 3 switches 22.
In fig. 4, the numbers in the square brackets indicate the numbers of the short-circuit abnormality determination processing in which the determination result is obtained, and the determination result includes the result of voltage determination indicating that the voltage between the source and the drain is abnormal, the result of current determination indicating that the phase current is high-current abnormal, and the result of protection determination indicating that the switching element is in the protection state. That is, the determination results of the short-circuit abnormality determination processing corresponding to the numbers in the brackets include a result of voltage determination indicating a source-drain voltage abnormality, a result of current determination indicating a high-current abnormality of the phase current, and a determination result of protection determination indicating a protection state of the switching element.
Hereinafter, the determination result of the short-circuit abnormality determination process including the result of the voltage determination indicating the source-drain voltage abnormality, the result of the current determination indicating the high-current abnormality of the phase current, and the determination result of the protection determination indicating the protection state of the switching element is referred to as "the determination result of the short-circuit abnormality determination process indicating the voltage abnormality, the high-current abnormality, and the protection activation".
Further, column 1 of the example of fig. 4 shows combinations of determination results of the short-circuit abnormality determination processing respectively indicating the voltage abnormality, the high-current abnormality, and the protection start. For example, in section 1 of column 1 of the example of FIG. 4, it is shown that: the determination result of the 1 st short-circuit abnormality determination process corresponds to the determination results of the short-circuit abnormality determination processes indicating the voltage abnormality, the high-current abnormality, and the protection of the cranking, and the determination result of the 2 nd short-circuit abnormality determination process corresponds to the determination results of the short-circuit abnormality determination processes indicating the voltage abnormality, the high-current abnormality, and the protection of the cranking.
< short-circuit abnormality determination processing by control section >
In this example, the control unit 50 sequentially performs 1 st to 24 th short-circuit abnormality determination processes and performs a short-circuit abnormality specification process. In the short-circuit abnormality determination process, the control section 50 determines an abnormal system (i.e., an electric power system regarded as having a short-circuit abnormality) from among the three-phase electric power systems configured by the electric power conversion circuit 20 and the motor 100, based on the correspondence relationship between the combination of the determination results of the short-circuit abnormality determination process shown in fig. 4 and the abnormal systems, and the combination of the determination results of the short-circuit abnormality determination process respectively indicating a voltage abnormality, a high-current abnormality, and protection of starting.
For example, in a case where the determination result of the 1 st short-circuit abnormality determination process matches the determination result of the short-circuit abnormality determination process indicating a voltage abnormality, a high-current abnormality, and protection of cranking and the determination result of the 2 nd short-circuit abnormality determination process matches the determination result of the short-circuit abnormality determination process indicating a voltage abnormality, a high-current abnormality, and protection of cranking, the control portion 50 determines that the U-phase power system in the three-phase power system configured by the power conversion circuit 20 and the motor 100 is an abnormal system.
Further, the control unit 50 turns off the switch 22 corresponding to the abnormal system specified in the short-circuit abnormality specification processing among the 3 switches 22, based on the correspondence relationship between the abnormal system and the switch 22 to be turned off shown in fig. 4.
For example, when it is determined in the short-circuit abnormality determination process that the U-phase power system among the three-phase power system including the power conversion circuit 20 and the motor 100 is an abnormal system, the control unit 50 turns off the U-phase switch 22U corresponding to the U-phase power system among the 3 switches 22.
[ open circuit abnormality determination processing and open circuit abnormality determination processing ]
The present inventors have also found that an electrical power system in which an open circuit abnormality occurs is detected from a three-phase electrical power system including the power conversion circuit 20 and the motor 100 by sequentially performing the 1 st to 24 th open circuit abnormality determination processes shown in fig. 5 and 6 and performing an open circuit abnormality determination process based on the correspondence relationship shown in fig. 7.
In this example, the control unit 50 sequentially performs the 1 st to 24 th open circuit abnormality determination processes shown in fig. 5 and 6, and performs the open circuit abnormality specification process according to the correspondence relationship shown in fig. 7. The open-circuit abnormality determination processing and the open-circuit abnormality specification processing are examples of open-circuit abnormality detection processing.
< open circuit abnormality determination processing >
Fig. 5 and 6 show the contents of the 1 st to 24 th open circuit abnormality determination processes. In fig. 5 and 6, "No." indicates the number of the open-circuit abnormality determination process, "H" indicates that the switching element is in the on state, and "L" indicates that the switching element is in the off state. The circular mark indicates that it is a detection object, and the x mark indicates that it is not a detection object.
As shown in fig. 5 and 6, in the 1 st to 24 th open circuit abnormality determination processes, the switching patterns of the switching elements Q1 to Q6 as the objects of the open circuit abnormality determination process, the phase voltage and the phase current as the objects of detection in the switching patterns, and the source-drain voltage and the phase current as the objects of determination in the switching patterns are determined in advance, respectively. For example, in the 1 st open circuit abnormality determination process, a switching pattern in which the 3 rd, 4 th switching elements Q3, Q4 are in an on state and the 1 st, 2 nd, 5 th, 6 th switching elements Q1, Q2, Q5, Q6 are in an off state is a target of processing, the U-phase voltage Vu, the W-phase voltage Vw, and the U-phase current iu in the switching pattern are targets of detection, the 3 rd, 4 th source-drain voltages VQ3, VQ4 in the switching pattern are targets of voltage determination, and the U-phase current iu in the switching pattern is a target of current comparison.
The 1 st to 4 th open circuit abnormality determination processes shown in fig. 5 are processes for detecting an open circuit abnormality of the U-phase power system caused by an open circuit fault of the U-phase winding of the motor 100. The 5 th to 8 th open circuit abnormality determination processes shown in fig. 5 are processes for detecting an open circuit abnormality of the V-phase power system caused by an open circuit fault of the V-phase winding of the motor 100. The 9 th to 12 th open circuit abnormality determination processes shown in the 9 th to 12 th paragraphs of the example of fig. 5 are processes for detecting an open circuit abnormality of the W-phase power system caused by an open circuit fault of the W-phase winding of the motor 100.
In addition, the 13 th and 14 th open-circuit abnormality determination processes shown in fig. 6 are processes for detecting an open-circuit abnormality of the U-phase power system caused by an open-circuit fault of the 4 th switching element Q4 of the power conversion circuit 20. The 15 th and 16 th open-circuit abnormality determination processes shown in fig. 6 are processes for detecting an open-circuit abnormality of the V-phase power system caused by an open-circuit fault of the 5 th switching element Q5 of the power conversion circuit 20. The 17 th and 18 th open abnormality determination processes shown in fig. 6 are processes for detecting an open abnormality of the W-phase power system caused by an open failure of the 6 th switching element Q6 of the power conversion circuit 20.
The 19 th and 20 th open-circuit abnormality determination processes shown in fig. 6 are processes for detecting an open-circuit abnormality of the U-phase power system caused by an open-circuit fault of the 1 st switching element Q1 of the power conversion circuit 20. The 21 st and 22 nd open-circuit abnormality determination processes shown in fig. 6 are processes for detecting an open-circuit abnormality of the V-phase power system caused by an open-circuit fault of the 2 nd switching element Q2 of the power conversion circuit 20. The 23 rd and 24 th open abnormality determination processes shown in fig. 6 are processes for detecting an open abnormality of the W-phase power system caused by an open failure of the 3 rd switching element Q3 of the power conversion circuit 20.
< open circuit abnormality determination processing by control section >
In this example, the control unit 50 performs the following operations in each of the 1 st to 24 th open circuit abnormality determination processes. In the following, an operation in the kth open circuit abnormality determination process will be described as an example.
First, when the switching patterns of the switching elements Q1 to Q6 are set to the switching patterns predetermined for the kth open-circuit abnormality determination process, the control unit 50 detects the phase voltage and the phase current predetermined as the detection target in the kth open-circuit abnormality determination process, among the 3 phase voltages Vu, Vv, Vw and the 3 phase currents iu, iv, iw. The detected phase current is a phase current that is determined in advance as a determination target in the kth open circuit abnormality determination process.
Next, the control unit 50 derives source-drain voltages predetermined as determination targets in the kth open circuit abnormality determination process among the 6 source-drain voltages VQ1 to VQ6, from the detected phase voltage, the power supply voltage VB applied to the 1 st input line 11, and the ground voltage VG applied to the 2 nd input line 12. The derived source-drain voltage is a source-drain voltage predetermined as a determination target in the kth open circuit abnormality determination process.
Then, the control unit 50 determines the voltage of the derived source-drain voltage. In this voltage determination, the control unit 50 compares the derived source-drain voltage with a normal voltage threshold, and determines that the source-drain voltage is abnormal when the source-drain voltage is lower than the normal voltage.
Further, the control unit 50 performs current determination on the detected phase current. In the current determination, the control unit 50 compares the detected phase current with a low-current threshold value, and determines that the phase current is a low-current abnormality when the phase current is lower than the low-current threshold value.
As described above, the 1 st to 24 th open circuit abnormality determination processes are sequentially performed. The determination result of the open circuit abnormality determination process includes a result of the voltage determination and a result of the current determination. That is, the determination result of the open-circuit abnormality determination process is a combination of the result of the voltage determination and the result of the current determination obtained in the specific switching mode of the switching elements Q1 to Q6.
< open circuit abnormality determination processing >
Fig. 7 shows a correspondence relationship among a combination of determination results of the open circuit abnormality determination processing, an abnormal system that is a power system considered to have an open circuit abnormality, and the switch 22 that should be put into an off state among the 3 switches 22.
In fig. 7, the numbers in the square brackets indicate the numbers of the open circuit abnormality determination processing in which the determination result is obtained, and the determination result includes the result of the voltage determination indicating that the source-drain voltage is abnormal and the result of the current determination indicating that the phase current is low-current abnormal. That is, the determination results of the open circuit abnormality determination processing corresponding to the numbers in the brackets include a voltage determination result indicating that the source-drain voltage is abnormal and a current determination result indicating that the phase current is low-current abnormal.
Hereinafter, the determination result of the open circuit abnormality determination process including the result of the voltage determination indicating the source-drain voltage abnormality and the result of the current determination indicating the phase current is the low current abnormality is referred to as "the determination result of the open circuit abnormality determination process indicating the voltage abnormality and the low current abnormality".
Further, column 1 of the example of fig. 7 shows combinations of determination results of the open-circuit abnormality determination processing respectively indicating the voltage abnormality and the low-current abnormality. For example, in section 1 of column 1 of the example of FIG. 7, it is shown that: the determination result of the 1 st open circuit abnormality determination process corresponds to the determination result of the open circuit abnormality determination process indicating the voltage abnormality and the low current abnormality, and the determination result of the 2 nd open circuit abnormality determination process corresponds to the determination result of the open circuit abnormality determination process indicating the voltage abnormality and the low current abnormality.
< open circuit abnormality determination processing by control section >
In this example, the control unit 50 sequentially performs the 1 st to 24 th open circuit abnormality determination processes and performs the open circuit abnormality specification process. In the open circuit abnormality determination process, the control portion 50 determines an abnormal system (i.e., an electric power system regarded as generating an open circuit abnormality) from among the three-phase electric power systems constituted by the electric power conversion circuit 20 and the motor 100, based on the correspondence relationship between the combination of the determination results of the open circuit abnormality determination process shown in fig. 7 and the abnormal system, and the combination of the determination results of the open circuit abnormality determination process indicating the voltage abnormality and the low-current abnormality, respectively.
For example, in a case where the determination result of the 1 st open circuit abnormality determination process matches the determination result of the open circuit abnormality determination process indicating a voltage abnormality and a low current abnormality and the determination result of the 2 nd open circuit abnormality determination process matches the determination result of the open circuit abnormality determination process indicating a voltage abnormality and a low current abnormality, the control portion 50 determines that the U-phase power system in the three-phase power system configured by the power conversion circuit 20 and the motor 100 is an abnormal system.
Further, the control unit 50 turns off the switch 22 corresponding to the abnormal system specified in the open circuit abnormality specification processing among the 3 switches 22, based on the correspondence relationship between the abnormal system and the switch 22 to be turned off shown in fig. 7.
For example, when it is determined in the open-circuit abnormality determination process that the U-phase power system among the three-phase power system including the power conversion circuit 20 and the motor 100 is an abnormal system, the control unit 50 turns off the U-phase switch 22U corresponding to the U-phase power system among the 3 switches 22.
[ Effect of the embodiment ]
As described above, by performing the abnormality detection process, it is possible to determine which of the three-phase power systems including the power conversion circuit 20 and the motor 100 has an abnormality.
Specifically, by performing the short-circuit abnormality detection process, it is possible to determine which of the three-phase power systems including the power conversion circuit 20 and the motor 100 has a short-circuit abnormality. Further, by performing the open-circuit abnormality detection processing, it is possible to determine which of the three-phase power systems including the power conversion circuit 20 and the motor 100 has an open-circuit abnormality.
Further, by setting the normal voltage threshold in the short-circuit abnormality detection processing higher than the protection voltage threshold in the drive circuit 40, it is possible to specify which of the three-phase power systems including the power conversion circuit 20 and the motor 100 has a short-circuit abnormality before the switching elements Q1 to Q6 are turned off by the protection function of the drive circuit 40.
Further, when an abnormality occurs in any of the three-phase power systems including the power conversion circuit 20 and the motor 100, the switch 22 corresponding to the power system in which the abnormality occurs among the 3 switches 22 is turned off, whereby the power supply of the power system in which the abnormality occurs among the three-phase power systems can be cut off, while the power supply of the power system in which the abnormality does not occur among the three-phase power systems can be continued. Accordingly, the power conversion device 10 can continue to supply power to the motor 100 using the power system in which no abnormality has occurred among the three-phase power systems, and thus the failure rate of the power conversion device 10 can be reduced.
(Power conversion System)
As shown in fig. 8, the power conversion device 10 shown in fig. 1 may be provided in the power conversion system 1. The power conversion system 1 shown in fig. 8 includes a plurality of power conversion devices 10. Each of the plurality of power conversion devices 10 supplies power to the three-phase ac motor 100. The configuration of the power converter 10 shown in fig. 8 is the same as the configuration of the power converter 10 shown in fig. 1.
In the power conversion system 1 of fig. 8, since the abnormality detection process can be performed in each of the plurality of power conversion devices 10, it is possible to determine which of the three-phase power systems including the power conversion circuit 20 and the motor 100 has an abnormality in each of the plurality of power conversion devices 10.
In the power conversion system 1 of fig. 8, when an abnormality occurs in any one of the three-phase power systems including the power conversion circuit 20 and the motor 100 in each of the plurality of power conversion devices 10, the switch 22 corresponding to the power system in which the abnormality occurs among the 3 switches 22 in the power conversion device 10 can be turned off. As a result, in each of the plurality of power conversion devices 10, the power supply of the power system in which the abnormality has occurred in the three-phase power system is cut off, while the power supply of the power system in which the abnormality has not occurred in the three-phase power system is continued. Therefore, in the power conversion device 10 having the power system in which the abnormality has occurred among the plurality of power conversion devices 10, the power supply from the power conversion device 10 to the motor 100 can be continued using the power system in which the abnormality has not occurred. Therefore, as compared with the case where all of the 3 switches are turned off and the power supply to all of the three-phase power systems is cut off in the power conversion device having the power system in which the abnormality has occurred among the plurality of power conversion devices, it is possible to suppress the decrease in the power supplied from the power conversion system 1 to the motor 100 due to the abnormality of the power system in the power conversion device 10.
(other embodiments)
In the above description, the case where the protection determination (determination as to whether or not the switching element is turned off by the protection function of the drive circuit 40) is performed in the short-circuit abnormality determination process is exemplified, but the protection determination may not be performed in the short-circuit abnormality determination process.
The above embodiments may be combined as appropriate. The above embodiments are merely preferable examples in nature, and are not intended to limit the scope of the present invention, its applications, or its uses.
[ industrial applicability ]
As described above, the technology disclosed herein is useful as a power conversion device.
Claims (6)
1. A power conversion device for supplying power to a three-phase AC motor,
the power conversion device includes:
a power conversion circuit having 6 switching elements connected in a three-phase bridge, the power conversion circuit converting input power into output power of three-phase alternating current by switching operations of the 6 switching elements; and
and a control unit that performs a voltage determination and a current determination for each of the 6 switching elements, determines whether or not a source-drain voltage predetermined as a determination target in the switching mode among source-drain voltages of the 6 switching elements is abnormal in the voltage determination, and determines whether or not a phase current predetermined as the determination target in the switching mode among 3 phase currents flowing through the power conversion circuit and the motor is abnormal in the current determination, wherein the control unit detects an abnormal power system from among three-phase power systems configured by the power conversion circuit and the motor, based on a result of the voltage determination and a result of the current determination obtained for each of the 6 switching elements.
2. The power conversion apparatus according to claim 1,
the power conversion device includes:
3 connection lines connecting the power conversion circuit and the motor; and
3 switches respectively arranged on the 3 connecting lines,
the control unit sets a switch corresponding to the power system in which the abnormality occurs among the 3 switches to an off state.
3. The power conversion apparatus according to claim 1 or 2,
in the voltage determination, the control unit determines that the inter-source-drain voltage is abnormal when the inter-source-drain voltage to be determined among the inter-source-drain voltages of the 6 switching elements is lower than a predetermined normal voltage threshold,
in the current determination, the control unit determines that the phase current is a high-current abnormality when a phase current to be determined among 3 phase currents flowing through the power conversion circuit and the motor is higher than a predetermined high-current threshold value,
the control unit detects an electric power system in which a short-circuit abnormality occurs from among three-phase electric power systems including the electric power conversion circuit and the motor, based on a combination of a result of voltage determination indicating that the source-drain voltage is abnormal and a result of current determination indicating that the phase current is high-current abnormal, among combinations of the results of voltage determination and the results of current determination obtained for each switching mode of the 6 switching elements.
4. The power conversion apparatus according to claim 3,
the power conversion device includes a drive circuit for controlling switching operations of the 6 switching elements,
the drive circuit turns off a switching element corresponding to a source-drain voltage lower than a predetermined protection voltage threshold among the 6 switching elements when a source-drain voltage lower than the protection voltage threshold is detected from among the source-drain voltages of the 6 switching elements,
the normal voltage threshold is higher than the protection voltage threshold.
5. The power conversion apparatus according to any one of claims 1 to 4,
in the voltage determination, the control unit determines that the inter-source-drain voltage is abnormal when the inter-source-drain voltage to be determined among the inter-source-drain voltages of the 6 switching elements is lower than a predetermined normal voltage threshold,
in the current determination, the control unit determines that the phase current is a low-current abnormality when a phase current to be determined among 3 phase currents flowing through the power conversion circuit and the motor is lower than a predetermined low-current threshold value,
the control unit detects an electric power system in which an open circuit abnormality occurs from among three-phase electric power systems including the electric power conversion circuit and the motor, based on a combination of a result of voltage determination indicating that the source-drain voltage is abnormal and a result of current determination indicating that the phase current is low-current abnormal, among combinations of the results of voltage determination and the results of current determination obtained for each switching mode of the 6 switching elements.
6. A power conversion system characterized in that,
the power conversion system includes a plurality of power conversion devices each supplying power to a three-phase AC motor,
the plurality of power conversion devices are constituted by the power conversion device according to any one of claims 1 to 5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018205602A JP2020072572A (en) | 2018-10-31 | 2018-10-31 | Power conversion device and power conversion system |
| JP2018-205602 | 2018-10-31 |
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| Publication Number | Publication Date |
|---|---|
| CN111130429A true CN111130429A (en) | 2020-05-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911034953.9A Withdrawn CN111130429A (en) | 2018-10-31 | 2019-10-29 | Power conversion device and power conversion system |
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| JP (1) | JP2020072572A (en) |
| CN (1) | CN111130429A (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5579495B2 (en) * | 2010-05-06 | 2014-08-27 | オムロンオートモーティブエレクトロニクス株式会社 | Motor drive device |
| JP6458697B2 (en) * | 2015-09-25 | 2019-01-30 | 株式会社デンソー | Motor drive abnormality type discrimination device |
| JP7010281B2 (en) * | 2017-03-08 | 2022-01-26 | 日本電産株式会社 | Power converter, motor drive unit and electric power steering device |
-
2018
- 2018-10-31 JP JP2018205602A patent/JP2020072572A/en active Pending
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2019
- 2019-10-29 CN CN201911034953.9A patent/CN111130429A/en not_active Withdrawn
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| JP2020072572A (en) | 2020-05-07 |
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