JP2004260883A - Power supply and power supply abnormality detection - Google Patents

Abstract

Provided is a power supply system having an abnormality detection device capable of accurately performing a self-diagnosis of an abnormality.
An abnormality detection includes a main circuit for supplying power to an external device, and a coupling capacitor, and is connected to the main circuit via the coupling capacitor to detect an abnormality of the main circuit. The above problem can be solved by the power supply device 200 including the device 202 and detecting an abnormality of the abnormality detection device 202 by changing the operation state of the main circuit 102.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply device used for driving an electric motor. More specifically, the present invention relates to a power supply device having an abnormality detection device capable of self-diagnosis of abnormality.
[0002]
[Prior art]
In electric vehicles and hybrid vehicles, a power supply device provided with orthogonal transform means including an inverter circuit is required in order to drive an AC-driven electric motor mounted thereon with a DC power supply such as a battery or a fuel cell.
[0003]
Since a high-voltage large-capacity DC power supply is incorporated in the power supply device and the impedance of its internal circuit is small, a malfunction is likely to occur due to electric leakage. Therefore, the power supply device is often provided with an abnormality detection device for detecting a leakage (for example, Japanese Patent Application Laid-Open No. H10-290529).
[0004]
As shown in FIG. 5, the power supply device 100 includes a main circuit 102 and an abnormality detection circuit 104. The main circuit 102 includes a DC power supply 10 and an inverter circuit 12, and orthogonally converts a DC voltage supplied from the DC power supply 10 by the inverter circuit 12 and supplies an AC voltage to the electric motor.
[0005]
The abnormality detection circuit 104 includes an oscillation power supply 14, a detection resistor 16, a coupling capacitor 18, a differential amplifier 20, a filter 22, and a self-diagnosis unit 24. One terminal a of the coupling capacitor 18 is connected to the output terminal of the DC power supply 10 included in the main circuit 102, and the other terminal b is connected to one terminal c of the detection resistor 16. The oscillation power supply 14 is connected between a terminal d of the detection resistor 16 and a ground point (a point maintained at the ground potential), and supplies a voltage V (f ₀ ) of a low frequency f ₀ to the terminal d. .
[0006]
The inverting input terminal of the differential amplifier 20 is connected to the terminal c of the detection resistor 16, and a voltage proportional to the potential difference between the threshold voltage Vs input to the non-inverting input terminal and the voltage at the terminal c is supplied to the filter 22. Filter 22 has a pass band around the reference frequency f _0, and outputs as a detection signal by extracting the frequency component of the reference frequency f ₀ near the output from the differential amplifier 20 S (f _0).
[0007]
The detection signal S (f ₀ ) changes in accordance with a change in the impedance of the main circuit 102. Therefore, as shown in FIG. 6, when a leakage occurs in the main circuit 102, the value of the detection signal S (f ₀ ) decreases when the main circuit 102 is in a steady operation. The leakage of the main circuit 102 can be detected by the decrease of the detection signal S (f ₀ ).
[0008]
Further, the abnormality detection device 104 is also provided with a self-diagnosis unit 24 for detecting an abnormality of the abnormality detection device 104 itself. The self-diagnosis unit 24 includes a high breakdown voltage phototransistor 26, a protection resistor 28, and a control unit 30. The collector of the high breakdown voltage phototransistor 24 is connected to the terminal c, and the emitter is connected to one end of the protection resistor 28. The other end of the protection resistor 28 is grounded. The base of the high breakdown voltage phototransistor 26 is connected to the control means 30.
[0009]
When a signal is input from the control means 30 to the base of the high-withstand-voltage phototransistor 26, the collector and the emitter are connected, and the input impedance as viewed from the oscillation power supply 14 becomes close to the impedance when leakage occurs in the main circuit 102. At this time, if the detection signal S (f ₀ ) decreases, it is determined that the abnormality detection device 104 is operating normally.
[0010]
[Patent Document 1]
JP-A-10-290529
[Problems to be solved by the invention]
In the self-diagnosis means 24, the terminal d of the detection resistor 16 is grounded via the protection resistor 28, so that the impedance of the main circuit 102 viewed from the terminal d of the detection resistor 16 is changed to the impedance when the main circuit 102 has a leakage. The abnormality of the abnormality detection device 104 is diagnosed by approximation. Therefore, when an abnormality occurs in the coupling capacitor 18 such as a decrease in insulation due to aging or the like, there is a problem that the abnormality cannot be detected.
[0012]
In addition, the conventional self-diagnosis unit 24 has a problem that the manufacturing cost is increased because the high-voltage phototransistor 26 having a high element unit price is included.
[0013]
The present invention has been made in view of the above problems, and has as its object to provide a power supply device and an abnormality detection device that can solve at least one of the above problems.
[0014]
[Means for Solving the Problems]
The present invention that can solve the above problems includes a main circuit for supplying power to an external device, and a coupling capacitor, and is connected via the main circuit and the coupling capacitor to detect an abnormality of the main circuit. A power supply device comprising: an abnormality detection device, wherein the power supply device includes a self-diagnosis unit that detects an abnormality of the abnormality detection device by changing an operation state of the main circuit.
[0015]
Here, the self-diagnosis unit changes the operation state of the main circuit, and then, when the terminal voltage of the coupling capacitor changes by a predetermined amount or more within a predetermined reference time, the abnormality detection device becomes abnormal. Is preferred.
[0016]
A main circuit for supplying power to an external device; an oscillation power supply; and a coupling capacitor, wherein the main circuit and the oscillation power supply are connected via the coupling capacitor, and a terminal voltage of the coupling capacitor. An abnormality detection device for detecting an abnormality of the main circuit based on a change in the terminal voltage of the coupling capacitor when outputting a predetermined reference voltage from the oscillation power supply; And self-diagnosis means for detecting an abnormality of the abnormality detecting device based on a difference between the terminal voltage of the coupling capacitor and a voltage other than the reference voltage.
[0017]
A main circuit for supplying power to an external device; an oscillation power supply; and a coupling capacitor, wherein the main circuit and the oscillation power supply are connected via the coupling capacitor, and a terminal voltage of the coupling capacitor. An abnormality detection device that detects an abnormality of the main circuit by a change in the terminal voltage of the coupling capacitor when a voltage of a predetermined reference frequency is output from the oscillation power supply, A self-diagnosis means for detecting an abnormality of the abnormality detecting device based on a difference from a terminal voltage of the coupling capacitor when a voltage other than the reference frequency is output from the oscillation power supply.
[0018]
The present invention that can solve the above problems includes an abnormality detection device that includes a coupling capacitor and detects an abnormality of the main circuit when the main circuit is connected to the main circuit via the coupling capacitor. It is characterized by including self-diagnosis means for detecting an abnormality by changing an operation state.
[0019]
Here, it is preferable that the self-diagnosis unit sets an abnormality when a terminal voltage of the coupling capacitor changes by a predetermined amount or more within a predetermined reference time after changing an operation state of the main circuit. is there.
[0020]
In addition, an oscillation power supply and a coupling capacitor are included, and when the main circuit and the oscillation power supply are connected via the coupling capacitor, an abnormality in the main circuit is detected by a change in terminal voltage of the coupling capacitor. An abnormality detection device, wherein a terminal voltage of the coupling capacitor when a predetermined reference voltage is output from the oscillation power supply and a cup voltage when a voltage other than the reference voltage is output from the oscillation power supply. It is characterized by including a self-diagnosis means for detecting an abnormality based on a difference from a terminal voltage of the ring capacitor.
[0021]
In addition, an oscillation power supply and a coupling capacitor are included, and when the main circuit and the oscillation power supply are connected via the coupling capacitor, an abnormality in the main circuit is detected by a change in terminal voltage of the coupling capacitor. An abnormality detection device, wherein a terminal voltage of the coupling capacitor when a voltage having a predetermined reference frequency is output from the oscillation power supply and a terminal voltage other than the reference frequency are output from the oscillation power supply. A self-diagnosis unit for detecting an abnormality based on a difference from a terminal voltage of the coupling capacitor is included.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0023]
A power supply device 200 according to an embodiment of the present invention includes a main circuit 102 and an abnormality detection circuit 202 as shown in FIG. The main circuit 102 includes a DC power supply 10 and an inverter circuit 12, and orthogonally converts a DC voltage supplied from the DC power supply by the inverter circuit 12 to supply an AC voltage to the electric motor.
[0024]
The abnormality detection circuit 202 basically includes the oscillation power supply 14, the detection resistor 16, the coupling capacitor 18, the differential amplifier 20, the filter 22, and the control means 40. One terminal A of the coupling capacitor 18 is connected to the output terminal of the DC power supply 10 included in the main circuit 102, and the other terminal B is connected to one terminal C of the detection resistor 16. The oscillation power supply 14 is connected between the terminal D of the detection resistor 16 to which the coupling capacitor 18 is not connected and the ground point (a point maintained at the ground potential).
[0025]
The oscillation power supply 14 supplies a voltage V (f ₀ ) of the reference frequency f _{0 to} the terminal D. Reference frequency _{f 0} of the output of the oscillation power can be, for example, to 2.5 Hz. The inverting input terminal of the differential amplifier 20 is connected to the terminal D of the detecting resistor 16, and the threshold voltage Vs input to the non-inverting input terminal and the voltage of the terminal B of the coupling capacitor 18 (common to the terminal C of the detecting resistor) Is supplied to the filter 22. Filter 22 has a pass band around the reference frequency f _0, and outputs as a detection signal by extracting the frequency component of the reference frequency f ₀ near the output from the differential amplifier 20 S (f _0). An abnormality such as leakage of the main circuit 102 can be detected by the decrease of the detection signal S (f ₀ ).
[0026]
Further, the abnormality detection device 200 includes a control unit 40. Control means 40 includes a microcomputer, and outputs a control signal S _C to the oscillation power source 14. Further, upon receiving the detection signal S (f ₀₎ and the open signal S _R, self-diagnose abnormality of the abnormality detection apparatus.
[0027]
First, outgoing power supply 14 is intended to stop the output and receives a control signal S _C. When the oscillation power supply 14 stops, the terminal B of the coupling capacitor 18 is grounded via the detection resistor 16 as shown in FIG. Oscillation power source 14, detection resistor 16, if the differential amplifier 20 and the filter 22 is operating normally, the frequency component of the reference frequency f ₀ superimposed on the voltage of the terminal B of the coupling capacitor 18 is reduced. Accompanying this, as shown in FIG. 3, the voltage of the detection signal S (f ₀ ) indicating a frequency component near the reference frequency f ₀ passing through the filter 22 changes. Accordingly, if changes by more than the reference change amount control signal S detected signal from the output start time after a predetermined reference time of _C S (f ₀₎ is predetermined from the control unit 40, an oscillation power source 14, detection It can be determined that the resistor 16, the differential amplifier 20, and the filter 22 are normal. Conversely, when the control signal S detection signal from the output start time after a predetermined reference time of _C S (f ₀₎ is not only a change reference change amount than the predetermined, the oscillation power source 14, detection resistor 16, the difference It can be determined that the dynamic amplifier 20 or the filter 22 is abnormal.
[0028]
That is, by stopping the oscillation power supply 14, an abnormality of the oscillation power supply 14, the detection resistor 16, the differential amplifier 20, or the filter 22 can be detected.
[0029]
Instead of completely stopping the oscillation power supply 14, the output from the oscillation power supply 14 is changed from a steady reference voltage, and the oscillation power supply is changed based on the change in the voltage of the detection signal S (f ₀ ) accompanying the change in the voltage. It is also possible to detect an abnormality of the detection resistor 16, the differential amplifier 20, or the filter 22.
[0030]
Moreover, instead of completely stopping the oscillation power source 14, outgoing power supply 14 may be one that changes the reference frequency f ₀ of the output voltage subjected to control signal S _C to the frequency f ₁ outside the pass band of the filter 22. Again, oscillation power source 14, detection resistor 16, if the differential amplifier 20 and the filter 22 is operating normally, the frequency component of the reference frequency f ₀ superimposed on the voltage of the terminal B of the coupling capacitor 18 As a result, the voltage of the detection signal S (f ₀ ) indicating a frequency component near the reference frequency f ₀ passing through the filter 22 changes. On the other hand, if there is an abnormality in the oscillation power supply 14, the detection resistor 16, the differential amplifier 20, or the filter 22, the voltage of the detection signal S (f ₀ ) does not largely change. Therefore, the abnormality of the oscillation power supply 14, the detection resistor 16, the differential amplifier 20, or the filter 22 can be detected based on the change of the detection signal S (f ₀ ).
[0031]
With the above method, it is possible to detect an abnormality that has occurred in the oscillation power supply 14, the detection resistor 16, the differential amplifier 20, or the filter 22, but it is not possible to detect an abnormality in the coupling capacitor 18 such as deterioration of insulation characteristics. Therefore, next, detection of an abnormality of the coupling capacitor 18 will be described.
[0032]
When the main relay 42 of the main circuit 102 is turned on or opened, the charge stored in the coupling capacitor 18 directly connected to the main circuit 102 fluctuates greatly. In addition, even when boosting or stepping down is performed in a short time in the main circuit 102, the charge stored in the coupling capacitor 18 greatly varies. An abnormality in the coupling capacitor 18 can be detected from a change in the terminal voltage of the coupling capacitor 18 when the operation state of the main circuit 102 is changed as described above.
[0033]
For example, the main relay 42 in the main circuit 102 to open signal S _R from the main relay 42 to the control unit 40 is sent when changed to the open state from the closed state. In the control unit 40, as shown in FIG. 4, the open signal S detected _R from received time after a predetermined reference time signal S (f ₀₎ is if the only change over the reference predetermined variation, It can be determined that the coupling capacitor 18 is normal. Conversely, when the open signal S detection signal from the time after a predetermined reference time that received the _R S (f ₀₎ is not only a change reference change amount than the predetermined includes a coupling capacitor 18 is abnormal You can judge.
[0034]
That is, the abnormality of the coupling capacitor 18 can be detected by opening the main relay 42 of the main circuit 102 and changing the operation state of the main circuit 102.
[0035]
Similarly, when the main relay 42 of the main circuit 102 is turned on, or when the voltage is stepped up or down for a short time, an abnormality in the coupling capacitor 18 can be detected based on the change in the detection signal S (f ₀ ). .
[0036]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the self-diagnosis of the abnormality of the abnormality detection apparatus containing a coupling capacitor can be performed correctly. Further, the abnormality detection device can be configured without using an expensive element such as a high breakdown voltage phototransistor.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a motor system according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating the operation of the abnormality detection device according to the embodiment of the present invention.
FIG. 3 is a diagram showing a change in a detection voltage S (f ₀ ) of the abnormality detection device according to the embodiment of the present invention.
FIG. 4 is a diagram showing a change in a detection voltage S (f ₀ ) of the abnormality detection device according to the embodiment of the present invention.
FIG. 5 is a block diagram showing a configuration of a conventional motor system.
FIG. 6 is a diagram showing a change in a detection voltage S (f ₀ ) of a conventional abnormality detection device.
[Explanation of symbols]
Reference Signs List 10 DC power supply, 12 inverter circuit, 14 oscillation power supply, 16 detection resistor, 18 coupling capacitor, 20 differential amplifier, 22 filter, 24 self-diagnosis means, 30, 40 control means, 42 main relay, 100 motor system, 102 mains Circuit, 104 abnormality detection device, 200 motor system, 202 abnormality detection device.

Claims (8)

A main circuit for supplying power to an external device;
An abnormality detection device including a coupling capacitor, connected via the main circuit and the coupling capacitor, and detecting an abnormality of the main circuit,
A power supply device comprising:
A power supply device comprising: a self-diagnosis unit that detects an abnormality of the abnormality detection device by changing an operation state of the main circuit. A main circuit for supplying power to an external device;
An abnormality detection device including an oscillation power supply and a coupling capacitor, wherein the main circuit and the oscillation power supply are connected via the coupling capacitor, and an abnormality of the main circuit is detected by a change in a terminal voltage of the coupling capacitor. ,
A power supply device comprising:
The terminal voltage of the coupling capacitor when outputting a predetermined reference voltage from the oscillation power supply, and the terminal voltage of the coupling capacitor when outputting a voltage other than the reference voltage from the oscillation power supply, And a self-diagnosis means for detecting an abnormality of the abnormality detection device based on a difference between the power supply devices. A main circuit for supplying power to an external device;
An abnormality detection device including an oscillation power supply and a coupling capacitor, wherein the main circuit and the oscillation power supply are connected via the coupling capacitor, and an abnormality of the main circuit is detected by a change in a terminal voltage of the coupling capacitor. ,
A power supply device comprising:
A terminal voltage of the coupling capacitor when a voltage of a predetermined reference frequency is output from the oscillation power supply, and a terminal voltage of the coupling capacitor when a voltage other than the reference frequency is output from the oscillation power supply And a self-diagnosis means for detecting an abnormality of the abnormality detection device based on a difference between the power supply device and the power supply device. The power supply device according to claim 1,
The self-diagnosis means is characterized in that, after changing the operation state of the main circuit, the abnormality detection device becomes abnormal when the terminal voltage of the coupling capacitor changes by a predetermined amount or more within a predetermined reference time. And power supply. An abnormality detection device that includes a coupling capacitor and detects an abnormality of the main circuit when the main circuit is connected via the coupling capacitor.
An abnormality detection device comprising: a self-diagnosis unit that detects an abnormality by changing an operation state of the main circuit. An abnormality detection including an oscillation power supply and a coupling capacitor, and detecting an abnormality of the main circuit by a change in a terminal voltage of the coupling capacitor when the main circuit and the oscillation power supply are connected via the coupling capacitor. A device,
The terminal voltage of the coupling capacitor when outputting a predetermined reference voltage from the oscillation power supply, and the terminal voltage of the coupling capacitor when outputting a voltage other than the reference voltage from the oscillation power supply, An abnormality detection device including self-diagnosis means for detecting an abnormality based on a difference between the two. An abnormality detection including an oscillation power supply and a coupling capacitor, and detecting an abnormality of the main circuit by a change in a terminal voltage of the coupling capacitor when the main circuit and the oscillation power supply are connected via the coupling capacitor. A device,
A terminal voltage of the coupling capacitor when a voltage of a predetermined reference frequency is output from the oscillation power supply, and a terminal voltage of the coupling capacitor when a voltage other than the reference frequency is output from the oscillation power supply And a self-diagnosis means for detecting an abnormality based on a difference between the abnormality detection device and the abnormality detection device. The abnormality detection device according to claim 5,
The self-diagnosis means, when changing the operation state of the main circuit, changes the terminal voltage of the coupling capacitor by a predetermined amount or more within a predetermined reference time within a predetermined reference time, and determines that the abnormality is abnormal. apparatus.

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