WO2015093188A1

WO2015093188A1 - Diagnostic device that identifies anomalies in electrical-power transmission path

Info

Publication number: WO2015093188A1
Application number: PCT/JP2014/079906
Authority: WO
Inventors: 門田　圭司; 山田　博之; 寛之竹本
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2013-12-20
Filing date: 2014-11-12
Publication date: 2015-06-25
Also published as: JPWO2015093188A1

Abstract

This invention provides a power-cable diagnostic device that can watch for degradation of a power cable at all times, regardless of an operating state associated with a primary power supply, and can detect symptoms of degradation accompanying short-duration phenomena such as cable sway. Said diagnostic device, which identifies anomalies in an electrical-power transmission path from a power supply to a load, has a reception unit that receives first information including the voltage across the power supply, second information including the voltage across the load, and third information including the current flowing through the power supply or the load. Said diagnostic device identifies anomalies in the electrical-power transmission path by computing the electrical resistance thereof on the basis of the aforementioned first information, second information, and third information and comparing said electrical resistance to a prescribed threshold.

Description

Diagnostic device for determining abnormality of power transmission path

The present invention relates to a diagnostic apparatus for determining an abnormality in a power transmission path.

In recent years, in many motor drive systems for hybrid vehicles and electric vehicles that have been developed, the output required for the motor for driving the vehicle connected to the axle is several tens of kW. To achieve this high output, A high performance battery such as a nickel metal hydride battery or a lithium ion battery is used, and the AC power is driven by converting DC power from these batteries into AC power by an inverter.

A battery that can store such high energy requires the precise management of the charge amount and charge / discharge power, so it is equipped with a monitoring unit that measures the battery voltage and input / output current and monitors the battery status. Yes. Also in the inverter, in order to achieve high motor efficiency, a control arithmetic device that performs control while monitoring the voltage applied from the power source to the inverter and the supply current to the motor is added.

And in such a motor drive system, the direct current supplied to the inverter which is a load from the battery of a power supply reaches several hundred A.

Therefore, it is desirable that the transmission path of the direct current has a sufficiently low resistance, and an abnormality that can increase the resistance of the transmission path needs to be detected as early as possible.

In Patent Document 1, a resistance detection unit including a degradation detection power source and an ammeter is attached in parallel to a DC current power cable between a main power source and a load, and degradation detection is performed by measuring the resistance value of the power cable. It is shown.

JP-A-62-288485

Although the method of Patent Document 1 can periodically diagnose the deterioration of the power cable, it cannot always detect the deterioration of the power cable, and is driven by a timer as shown in Patent Document 1. It is necessary to provide a changeover switch and detect deterioration at predetermined time intervals. Furthermore, although not explicitly described in Patent Document 1, during operation with the main power source, current from other than the degradation detection power source flows through the resistance meter, and therefore degradation detection may not be possible.

On the other hand, in order to detect the deterioration of the power cable mounted on the vehicle at an early stage, it is necessary to constantly monitor the disconnection of the power cable with respect to the fluctuation of the power cable because the disconnected part of the power cable repeats contact and non-contact. is there. Especially when applied to vehicles, the oscillation of the power cable occurs only during traveling, that is, only in the operating state with the main power supply. There is a risk of being late.

An object of the present invention is to provide a power cable that can constantly monitor the deterioration of the power cable regardless of the operating state of the main power source and can detect signs of deterioration appearing with a short-time phenomenon such as a cable swing. It is to provide a diagnostic apparatus.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, in the diagnostic apparatus for determining an abnormality in the power transmission path from the power supply to the load, the first information including the voltage value of the power supply A receiving unit that receives the second information including the voltage value of the load and the third information including the current value of the power source or the load, and includes the first information and the second information. Based on the third information, an electrical resistance of the power transmission path is calculated, the electrical resistance is compared with a predetermined threshold value, and abnormality of the power transmission path is determined.

According to the present invention, a power cable that can constantly monitor the deterioration of the power cable regardless of the operating state of the main power source and can detect signs of deterioration that appear with a short-time phenomenon such as cable swinging. A diagnostic apparatus can be provided.

Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a schematic diagram of a power device according to an embodiment of the present invention. 6 is a flowchart from the start to the end of diagnosis of a power transmission path according to an embodiment of the present invention. The timing chart at the time of the power cable degradation detection by embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a power device according to an embodiment of the present invention. A battery 1 as a DC power source, an inverter 2 as a load, a motor 4 driven by the inverter 2, and DC power from the battery 1 to the inverter 2 are transmitted. And an inverter control unit 6 for controlling the inverter 2.

The battery 1 is a secondary battery such as a nickel metal hydride battery or a lithium ion battery, and holds a high voltage of about 100 V to 300 V. The battery monitoring unit 5 detects the current of the battery 1 and the power supply voltage, respectively. This is performed by the unit 520 and the voltage detection unit 530. These current and power supply voltage are transmitted to the communication line 7 by the communication control unit 510.

The inverter 2 includes transistors 230, and these transistors are on / off controlled by a PWM signal supplied from the inverter control unit 6, so that the motor 4 is driven by the supply of electric power from the battery 1.

As for this PWM signal, an external torque command given from the outside of the inverter control unit 6 is inputted to the torque limiting unit 640 and a target torque is outputted to the current map unit 650, and the current map unit 650 receives a signal from the motor rotation sensor 410. The target current is output to the current control unit 660 from the motor rotational speed and the target torque calculated by the rotation detection unit 680, and the current control unit 660 uses the signal from the three-phase current sensor 240 to output to the current detection unit 690. The target voltage is output to the PWM control unit 670 from the calculated three-phase current and the target current, and the PWM control unit 670 is output using the load voltage and the target voltage from the voltage detection unit 630.

The power cable diagnosis unit 620 calculates the power from the current and power supply voltage received by the communication control unit 610 from the communication line 7, the negative overvoltage input from the voltage detection unit 630, and the target torque input from the torque limiting unit 640. Diagnose the cable.

Hereinafter, the operation of the system when diagnosing a power cable will be described.

The inverter control unit 6 outputs a PWM signal to the inverter 2 via the current map unit 650, the current control unit 660, and the PWM control unit 670 when an external torque command is input to the torque limiting unit 640. The transistor 230 of the inverter starts on / off control. As a result, the voltage generated by the battery 1 is applied to the motor 4, current is supplied from the battery 1 to the motor 4 via the power cable 3 and the inverter 2, and the motor 4 is driven.

At this time, the power cable diagnosis unit 620 determines whether or not a target torque equal to or greater than a predetermined value, which is a condition for starting diagnosis, is input from the torque limiting unit 640, and a current equal to or greater than the predetermined value is low-pass from the communication control unit 610. It is determined whether or not the input is made through the filter 612.

If the condition for starting the diagnosis is satisfied, the power cable diagnosis unit 620 from the communication control unit 610 through the low-pass filter of each signal, from the power supply voltage V1, the current I, and the negative overvoltage V2, A resistance value R of the power transmission path including the power cable 3 between the power supply voltage sensor 120 and the load voltage sensor 210 is calculated by the following equation.
R = | V2-V1 | / | I |

The resistance value R includes the resistance value of the power cable 3, the resistance value of the connection portion between the power cable 3 and the battery 1, and the resistance value of the connection portion of the power cable 3 and the inverter 2. Even if there is an abnormality in the resistance value of the location, it appears as an abnormality in the resistance value R.

Next, the power cable diagnosis unit 620 compares the resistance value R with the first abnormality detection value R1, and if the resistance value R is greater than the first abnormality detection value R1, the power cable diagnosis unit 620 The resistance value R is determined to be out of the normal range, and a first abnormal state is output to the communication control unit 610 as a diagnosis result. The communication control unit 610 transmits a diagnosis result to the communication control unit 830 of the warning device 8 via the communication line 7, the communication control unit 830 inputs the diagnosis result to the warning light control device 820, and the warning light control device 820 In response to the first abnormal state, the warning lamp 810 is turned on.

Furthermore, the power cable diagnosis unit 620 compares the resistance value R with the second abnormality detection value R2, and if the resistance value R is greater than the second abnormality detection value R2, the power cable diagnosis unit 620 It is determined that output restriction is necessary, and a diagnosis result is output to the torque limiting unit 640 that the second abnormal state is present, and the torque limiting unit 640 is less than or equal to a predetermined torque limit in the second abnormal state. When the output of the target torque to the current map unit 650 is limited and the external torque command is larger than the predetermined limit torque, the target torque is set to the predetermined limit torque, and the external torque command is equal to or less than the predetermined limit torque. If it is, the value of the external torque command is output to the current map unit 650 as the value of the target torque.

Finally, the power cable diagnosis unit 620 compares the resistance value R with the third abnormality detection value R3. If the resistance value R is greater than the third abnormality detection value R3, the power cable diagnosis unit 620 Then, it is determined that the operation stop is necessary, and a diagnosis result is output to the PWM control unit 670 that it is in the third abnormal state, and the PWM control unit 670 stops outputting the PWM signal to the inverter 2.

FIG. 2 is a flowchart showing the operation of the power device when diagnosing the power cable, one diagnosis cycle, that is, from the start of diagnosis to the end of diagnosis.

First, in S1, it is determined whether or not the power device has started operation, whether or not the target torque is greater than or equal to a predetermined value, and whether or not the current is greater than or equal to a predetermined value. If the condition is not satisfied, S1 is executed again, and if it is satisfied, the process proceeds to S2. In S2, the resistance R is calculated from the negative overvoltage V2, the power supply voltage V1, and the current I and substituted. Thereafter, the process proceeds to S3, where it is determined whether or not the resistance value R is greater than the first abnormality detection value R1. If not, the diagnosis ends. If it is greater, the process proceeds to S4 and the warning lamp is turned on. In S5, it is determined whether or not the resistance value R is larger than the second abnormality detection value R2. If not, the diagnosis ends. If it is larger, the process proceeds to S6, and the target torque is limited to a predetermined value or less. Next, the process proceeds to S7, where it is determined whether or not the resistance value R is greater than the third abnormality detection value R3. If it is not larger, the diagnosis ends. If it is larger, the process proceeds to S8 and the PWM signal output is stopped. Next, the diagnosis ends, and one diagnosis cycle ends.

FIG. 3 is a time chart showing the operation when the power device starts operating and the power cable diagnostic device detects an abnormality in the power cable.

At T1, the external torque command increases from 0 Nm to 100 Nm, and in response, the target torque increases from 0 Nm to 100 Nm, and the current also increases from 0 A to 200 A.

If the predetermined thresholds for the target torque and current for the power cable diagnosis unit 620 to start diagnosis are, for example, the target torque is 10 Nm or more and the current is 10 A or more, the power cable diagnosis device diagnoses T1. Start. At that time, at T1, the resistance R calculated by the power cable diagnosis unit 620 is, for example, 3 mΩ.

Thereafter, at T2, when the resistance of the power cable 3 increases and the resistance R increases to 10 mΩ, for example, when the first abnormality detection value R1 is 5 mΩ, the power cable diagnosis unit 620 sends a diagnosis result to the warning light control unit 820. , The warning lamp 810 is turned on.

After that, when the resistance of the power cable 3 increases and the resistance R increases to 100 mΩ at T3, for example, when the second abnormality detection value R2 is 50 mΩ, the power cable diagnosis unit 620 sends a diagnosis result to the torque control unit. Is transmitted to limit the target torque to a predetermined value or less.

Thereafter, when the resistance of the power cable 3 further increases at T4 and the resistance R increases to 1000 mΩ, for example, when the third abnormality detection value R3 is 500 mΩ, the power cable diagnosis unit 620 diagnoses the PWM control unit. By sending the result, the PWM signal is stopped.

The present invention is a power device comprising a general power source and a power source monitoring device such as a battery monitoring unit 5, a load and a load control device such as an inverter control unit 6, and a power cable connecting them. If it has a function to communicate with each other, it can be realized by adding a power cable diagnostic unit to the load control device, and since the power cable diagnostic unit can be realized by changing the control program, the cost increases due to the addition of parts There is no.

Note that the power cable diagnosis unit is not limited to the load control device, and may be provided in a power supply monitoring device or other devices connected by communication.

In the above description, the case where the present embodiment is applied to a power device using a battery as a power source and an inverter and a motor as a load has been described. However, the present embodiment can also be applied to other types of power sources and other electrical loads. The present embodiment is not limited to this.

The embodiment disclosed this time is illustrative in all respects and not restrictive. The technical scope of the present embodiment is defined by the claims, and all modifications within the scope equivalent to the configuration described therein are also included in the technical scope of the present embodiment.

DESCRIPTION OF SYMBOLS 1 Battery 2 Inverter 3 Power cable 4 Motor 5 Battery monitoring unit 6 Inverter control unit 7 Communication line 8 Warning device 110 Current sensor 120 Power supply voltage sensor 210 Load voltage sensor 220 Smoothing capacitor 230 Transistor 240 Three-phase current sensor 410 Motor rotation sensor 510 Communication Control unit 520 Current detection unit 530 Voltage detection unit 610 Communication control unit 620 Power cable diagnosis unit 630 Voltage detection unit 640 Torque limit unit 650 Current map unit 660 Current control unit 670 PWM control unit 680 Rotation detection unit 690

Current detection unit

611, 612 , 613 Low-pass filter 810 Warning light 820 Warning light control unit 830 Communication control unit

Claims

In the diagnostic device for judging the abnormality of the power transmission path from the power source to the load,
First information including a voltage value of the power supply;
Second information including a voltage value of the load;
A receiver that receives the third information including the current value of the power source or the load;
Based on the first information, the second information, and the third information,
Calculating the electrical resistance of the power transmission path;
Comparing the electrical resistance with a predetermined threshold;
A diagnostic apparatus for determining an abnormality in the power transmission path.
In the diagnostic apparatus which determines abnormality of the electric power transmission path according to claim 1,
The current value is the current value of the load.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path according to claim 1 or 2,
The current value is a voltage applied to the load,
And a value estimated from the operating state of the load,
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 3,
The determination of the abnormality is
Only when the current value is greater than a predetermined value,
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path in any one of Claim 1 to 4,
The determination of the abnormality is
Only when the time change rate of the current value is smaller than a predetermined value,
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic device for judging the abnormality of the power transmission path from the power source to the load,
First information including a voltage value of the power supply;
Second information including a voltage value of the load;
A receiver that receives the third information including the operating state of the load;
Based on the first information, the second information, and the third information,
Comparing the difference between the first information and the second information with the third information;
A diagnostic apparatus for determining an abnormality in the power transmission path.
In the diagnostic device for judging the abnormality of the power transmission path from the power source to the load,
First information including a voltage value of the power supply;
A receiving unit that receives second information including a voltage value of the load;
Based on the first information and the second information,
Comparing the difference between the first information and the second information and a predetermined threshold;
A diagnostic apparatus for determining an abnormality in the power transmission path.
In the diagnostic apparatus which determines abnormality of the electric power transmission path according to claim 7,
The determination of abnormality is performed when the operating state of the load is equal to or higher than a predetermined output.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 8,
The determination of abnormality is performed when the operating state of the load is equal to or higher than a predetermined output.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path in any one of Claim 1 to 9,
The determination of abnormality is performed when the operating state of the load is equal to or less than a predetermined output change rate.
It is characterized by
A diagnostic apparatus for determining an abnormality in the power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 10,
The first information, the second information, or the third information;
Or, among the electric resistance of the power transmission path calculated based on these,
A diagnostic apparatus for determining an abnormality in a power transmission path, wherein at least one is subjected to a filtering process using a low-pass filter having a predetermined time constant.
In the diagnostic apparatus which determines abnormality of the electric power transmission path according to claim 11,
The predetermined time constant is determined using at least one of a driving frequency of the load and an electric resonance frequency of a closed circuit configured by the power source, the load, and the power transmission path.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 12,
The number of times that the abnormality is determined per second is equal to or higher than the resonance frequency of mechanical oscillation of the power transmission path.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path in any one of Claims 1-13,
Furthermore, using a warning device that informs the driver of the power supply or the load of any abnormality by either light, sound, or an unusual operation of the load,
After the power transmission path is determined to be abnormal, the warning device notifies the driver of the abnormality.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 14,
Furthermore, using a storage device that stores the results of past diagnosis,
After it is determined that the power transmission path is abnormal, the power transmission path is regarded as abnormal regardless of the calculation result of the resistance value of the power transmission path until the storage device is erased.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 15,
Furthermore, using a storage device that stores past calculation results of electrical resistance,
The comparison between the electrical resistance and the predetermined threshold value is performed by comparing the past electrical resistance stored in a storage device in advance with the electrical resistance after calculating the electrical resistance. When the resistance is larger, the past electric resistance is compared with the predetermined threshold value.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 16,
The predetermined threshold value is a manufacturing variation upper limit value of the resistance value of the power transmission path in a normal state.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which judges abnormality of the electric power transmission path according to claim 17,
Furthermore, using a warning light to inform the driver of the power source or the load,
After determining that the power transmission path is abnormal, inform the driver of the abnormality with the warning light,
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 18,
The predetermined threshold value is a resistance value at which the power transmission path can deviate from a normal temperature range when the load is operated so that a maximum current flows through the power transmission path.
A diagnostic apparatus for determining an abnormality in a power transmission path.
The diagnostic apparatus for determining an abnormality of the power transmission path according to claim 19,
After the power transmission path is determined to be abnormal, the load output is limited to a predetermined output.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines the abnormality of the electric power transmission path | route in any one of Claim 1 to 20,
Providing another threshold value greater than the predetermined threshold value;
When the load is operated while being limited to the predetermined output, the resistance value is such that the power transmission path can deviate from a normal temperature range.
A diagnostic apparatus for determining an abnormality in a power transmission path.
In the diagnostic apparatus which determines abnormality of the electric power transmission path according to claim 21,
After the power transmission path is determined to be abnormal, the output of the load is stopped.
A diagnostic apparatus for determining an abnormality in a power transmission path.