JP2004257765A - Apparatus for diagnosing breakage of wire of rotation angle detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for diagnosing the breakage of wires of a rotation angle detection device of a dynamo-electric machine. <P>SOLUTION: An R/D converting IC 1 converts a rotation angle signal of a motor 6 detected by a resolver 7 into a digital signal and outputs it to a CPU 2. A signal line A is connected, for example, between an output terminal PA and an input terminal P1 of the CPU 2 between the R/D converting IC 1 and the CPU, and a resistor 4a for diagnosis is connected between the signal line A and a diagnosis output terminal PD1. The CPU 2 detects that the output terminal PA has failed due to the breakage of wires when it is determined that the condition that an input signal when a Hi signal is outputted from the diagnosis output terminal PD1 is Hi and that an input signal when a Lo signal is outputted from the diagnosis output terminal is Lo has continued for a prescribed time or longer. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a disconnection diagnosis device.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. H11-337371 In Japanese Patent Application Laid-Open No. H11-337371, a resolver that outputs a signal corresponding to the rotation angle of a motor, and a signal that is output from the resolver is converted into a digital signal to convert the motor into a digital signal. An R / D conversion circuit that outputs a digital signal (for example, an A-phase signal and a B-phase signal) according to the rotation, and a CPU that detects the rotation angle of the electric motor based on the digital signal output from the R / D conversion circuit 2. Description of the Related Art There is known a rotation angle detecting device for a motor provided.
[0003]
In such a rotation angle detecting device, as a method of detecting a disconnection of a signal line between the R / D conversion circuit and the CPU, for example, a pull-up power supply is connected to the signal line via a resistor, or a pull-down power supply is connected via a resistor. It is conceivable to detect the occurrence of disconnection by detecting that the potential of the signal line connected to the power supply and connected to the CPU is fixed at the pull-up or pull-down potential.
[0004]
[Problems to be solved by the invention]
However, as described above, for example, when disconnection is detected by connecting a signal line to a pull-up power supply via a resistor, the signal output from the R / D conversion circuit is a digital signal of Hi and Lo signals. Even if the potential of the input terminal is fixed at Hi (high potential), whether the potential of the input terminal is Hi due to disconnection or because the signal output from the A / D conversion circuit is a Hi signal Since it is not possible to determine whether the potential of the terminal is Hi, it is not possible to detect a disconnection only because the potential of the input terminal is Hi.
[0005]
Further, when the input terminal of the CPU (CPU side from the connection point between the signal line and the pull-up power supply) is disconnected, the input terminal of the CPU is opened, and the potential of the input terminal of the CPU becomes the potential of the signal line at the time of disconnection. For example, when the input terminal is fixed to Lo, the potential of the input terminal does not become Hi, so that the disconnection cannot be detected in the same manner. The same applies to the case where a pull-down power supply is connected.
The present invention relates to a rotation angle detection device for a rotating machine including an R / D conversion circuit for converting an output signal of a resolver into a digital signal, and rotation angle detection means connected to the R / D conversion circuit for calculating a rotation angle. It is an object of the present invention to provide a disconnection diagnostic device capable of detecting occurrence of disconnection between an R / D conversion circuit and a rotation angle detecting means.
[0006]
[Means for Solving the Problems]
For this reason, the present invention provides an R / D converter that outputs a signal corresponding to the rotation angle of a rotating machine input from a resolver as a digital signal composed of Hi and Lo signals, and an R / D converter connected to the R / D converter. In a rotation angle detection device including rotation angle detection means for detecting a rotation angle, a diagnosis output terminal for alternately outputting Hi and Lo signals is provided, and the diagnosis output terminal, the R / D converter, and the rotation angle detection means are provided. A diagnostic resistor is connected between the signal lines to be connected, and when the Hi signal is output from the diagnostic output terminal, the input signal to the input terminal of the rotation angle detecting means is Hi, and the Lo signal is output from the diagnostic output terminal. Disconnection detection function that determines that the output terminal of the R / D converter has a disconnection failure if the state where the input signal to the input terminal of the rotation angle detection means at the time of outputting the signal is Lo continues for a predetermined time or more. I have It was.
[0007]
【The invention's effect】
According to the present invention, the resistance value of the input resistance of the rotation angle detecting means is made larger than the output resistance of the R / D converter, and the resistance value of the diagnostic resistance is larger than the output resistance of the R / D converter. Since the input resistance is set lower than the input resistance of the rotation angle detecting means, when there is no disconnection between the R / D converter and the rotation angle detecting means, the R / D converter is not affected by the potential of the diagnostic output terminal. Can be accurately transmitted to the rotation angle detecting means.
[0008]
When a disconnection failure occurs on the output terminal side of the R / D converter, the output signal of the diagnostic output terminal is applied to the input terminal of the rotation angle detecting means by a diagnostic resistor connected between the diagnostic output terminal and the signal line. You. Therefore, if the pulse width of the output signal of the diagnostic output terminal is set to be larger than the pulse width of the output signal of the R / D converter, a pulse wider than the normal input signal is detected at the input terminal, and the R / D conversion is performed. It can be determined that a disconnection failure has occurred on the output terminal side of the converter.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the invention will be described with reference to examples.
FIG. 1 shows an interface circuit used in a motor drive inverter circuit for an electric vehicle.
A resolver 7 is connected to a motor 6 as a drive source of the electric vehicle, and an R / D conversion IC 1 is connected to an output of the resolver 7.
From the R / D conversion IC 1, phase pulse signals A and B for measuring the number of rotations of the motor 6, signals U, V and W representing the axis angle of the motor 6, and a self-diagnosis result signal ERR of the R / D conversion IC 1 Are connected to the CPU 2 in total.
[0010]
That is, between the R / D conversion IC1 and the CPU2, the signal line A between the PA output terminal and the P1 input terminal, the signal line B between the PB output terminal and the P2 input terminal, the PU output terminal and the P3 input terminal. The signal line U, the signal line V between the PV output terminal and the P4 input terminal, the signal line W between the PW output terminal and the P5 input terminal, the signal line ERR and the PCS input between the PREE output terminal and the P6 input terminal. The signal line CS is connected between the terminal and the PD2 output terminal.
[0011]
Among the signals output by the R / D conversion IC 1, the self-diagnosis result signal ERR from the PREE output terminal is at the Hi level when the self-diagnosis result is abnormal, and is at the Lo level when the self-diagnosis result is normal. The other signals A, B, U, V, and W become Hi level or Lo level in accordance with the rotation of the motor 6, and the levels change with time.
In order to diagnose the disconnection of the above-mentioned six signal lines A, B, U, V, W, and ERR, one end of each of the resistors 4a, 4b, 4c, 4d, 4e, and 4f as a diagnostic resistor is provided. Are connected, and the other ends of the resistors 4a to 4f are all connected to a diagnostic output terminal PD1 of the CPU 2 in common.
[0012]
The resistance values of the resistors 4a to 4f are determined by the output terminals PA, PB, PU, PV, PW, R / D converter IC1 connected to the six signal lines A, B, U, V, W, and ERR. It is set sufficiently higher than the output resistance of the PERR, and each signal output from the R / D conversion IC 1 is accurately transmitted to the CPU 2 irrespective of the level of the diagnostic output terminal PD 1.
[0013]
The input resistance of each terminal of the CPU 2 is larger than the resistance value of the output resistance of the corresponding output terminal of the R / D conversion IC 1, and the resistance values of the resistors 4a to 4f are set to the respective input terminals P1 to P6 of the CPU 2. When the output terminals PA, PB, PU, PV, PW, and PERR of the R / D converter IC1 are in the open state, the signal level of the diagnostic output terminal PD1 is set to be lower than that of the CPU2. It is transmitted to the input terminal. As an example, assuming that the output resistance of the R / D conversion IC 1 is 1 KΩ and the input resistance of the input terminal of the CPU 2 is 1 MΩ, the resistance values of the resistors 4 a to 4 f can be about 100 KΩ.
[0014]
When the potential of the PCS input terminal of the R / D conversion IC 1 becomes Lo level, the above-described six signal lines A, B, U, V, W, and ERR output levels corresponding to the respective levels. However, when the potential of the PCS input terminal becomes Hi level, the output resistances of the above-described six signal lines A, B, U, V, W, and ERR become high impedance, and the output of those signals is cut off. You.
[0015]
This is a function for selecting a circuit for transmitting / receiving signals when connecting a plurality of peripheral circuits including the R / D conversion IC 1 to the CPU 2 and sharing the connection terminal of the CPU 2 with other peripheral circuits. However, in the present embodiment, only the R / D conversion IC1 is connected to the output terminal PD2 which is a dedicated terminal of the CPU2, and is not used for the original circuit selection, but for the diagnosis to be described later. Used for
The signal line CS connected to the input terminal PCS is provided with a pull-down resistor 5, and when the CPU 2 is reset or the terminal has an open failure on the CPU 2 side, the above-described six signal lines A, B, U, The output levels of V, W, and ERR are normally transmitted to the CPU 2.
[0016]
Next, a procedure of disconnection diagnosis in this embodiment will be described.
FIG. 2 is a flowchart showing the flow of the disconnection diagnosis.
This diagnosis is roughly divided into two stages, an initial diagnosis performed immediately after the power is turned on and a start of a normal control using a signal output from the R / D conversion IC 1, and a subsequent start of the normal control. It is divided into regular diagnosis to be performed.
In the initial diagnosis, in step 100, the CPU 2 sets the output of the output terminal PD2 to Hi level. Thus, the above-described six signal lines A, B, U, V, W, and ERR are in a state (high impedance) separated from the CPU 2.
[0017]
Next, in step 110, the diagnostic output terminal PD1 is set to Hi level. As a result, a Hi-level signal is applied to the input terminal P1 of the CPU 2 via the resistor 4a and the signal line A.
Subsequently, in step 120, the CPU 2 determines whether or not the input terminal P1 is at the Hi level. If an affirmative determination is made here, the Hi-level signal output from the diagnostic output terminal PD1 has been normally read, and the input terminal P1 on the CPU 2 side is considered to be connected to the resistor 4a. Move to.
If a negative determination is made in step 120, the Hi-level signal output from the diagnostic output terminal PD1 is not normally transmitted, and it is determined in step 150 that the CPU2 side terminal open fault has occurred.
[0018]
In step 130, the diagnostic output terminal PD1 is set to Lo level.
As a result, a Lo level signal is applied to the signal line A via the resistor 4a.
Subsequently, in step 140, the CPU 2 determines whether or not the input terminal P1 is at the Lo level. If an affirmative determination is made here, the Lo level output from the diagnostic output terminal PD1 has been normally read, and it is considered that the input terminal P1 on the CPU 2 side is connected, and the routine proceeds to step 160.
If a negative determination is made in step 140, the Lo level signal output from the diagnostic output terminal PD1 is not normally transmitted, and it is determined in step 150 that the CPU2 side terminal open failure has occurred.
[0019]
In step 160, the output terminal PD2 is set to the Lo level. As a result, a signal can be transmitted between the R / D conversion IC 1 and the CPU 2, the initial diagnosis is determined to be completed, normal control using the signal output from the R / D conversion IC 1 is started, and the diagnosis is constantly shifted to the diagnosis. .
[0020]
Next, the procedure of the constant diagnosis will be described.
When the normal control is started in step 170, first, in step 180, the time measurement timer α built in the CPU 2 is reset and started.
Next, in step 190, the diagnostic output terminal PD1 is set to the Hi level. Thus, a Hi-level signal is applied to the signal line A via the resistor 4a.
[0021]
Subsequently, in step 200, the CPU 2 determines whether or not the input terminal P1 is at the Hi level. If a positive determination is made here, the signal line A is in the same state as the output level of the diagnostic output terminal PD1, and there is a possibility that the signal output from the output terminal PA of the R / D conversion IC1 has not been transmitted to the CPU2. If so, the process proceeds to the next diagnosis step 210.
If a negative determination is made in step 200, the Lo level signal output from the output terminal PA of the R / D conversion IC1 is transmitted to the CPU 2 regardless of the level signal output from the diagnostic output terminal PD1. The output terminal PA on the side of the R / D conversion IC 1 is regarded as being connected, and the routine always returns to step 180, which is the head of the diagnosis, and repeats the same procedure again.
[0022]
If an affirmative determination is made in step 200, the diagnostic output terminal PD1 is set to the Lo level in step 210 in order to continue the determination.
As a result, a Lo level signal is applied to the signal line A via the resistor 4a.
Subsequently, in step 220, the CPU 2 determines whether or not the input terminal P1 is at the Lo level. If an affirmative determination is made here, the signal line A is in the same state as the output level of the diagnostic output terminal PD1, and the signal of the level output from the output terminal PA of the R / D conversion IC1 may not be transmitted to the CPU2. If so, the process proceeds to the next diagnosis step 230.
[0023]
If a negative determination is made in step 220, the Hi-level signal output from the output terminal PA of the R / D conversion IC1 is transmitted to the CPU 2, regardless of the level signal output from the diagnostic output terminal PD1. The output terminal PA on the side of the R / D conversion IC 1 is regarded as being connected, so that the routine always returns to the first step 180 of the diagnosis and repeats the same procedure again.
[0024]
In step 230, it is determined whether or not the value of the time measurement timer α has elapsed from the start of the time measurement, 100 ms, which is longer than the signal of the output terminal PA. If a negative determination is made here, it is determined that the output level of the output terminal PA of the R / D conversion IC1 coincides with the output level of the diagnostic output terminal PD1 by accident in the constant diagnosis, and the process returns to step 190 to continue the above-described diagnostic procedure. repeat.
If an affirmative determination is made here, the state in which the output level of the output terminal PA of the R / D conversion IC1 matches the output level of the diagnostic output terminal PD1 continues for 100 ms, and the output terminal PA of the R / D conversion IC1. Are not transmitted to the CPU 2 normally, and it is determined that the output terminal PA of the R / D conversion IC 1 has an open failure.
[0025]
As a result of the above diagnosis, if it is determined that the terminal of the R / D conversion IC 1 or the CPU 2 has a terminal open failure, for example, a warning lamp is turned on to notify the driver of the failure of the circuit, and the device is repaired or replaced. Action can be encouraged.
Although the signal line A has been described above, the other five signal lines B, U, V, W, and ERR can be diagnosed by the same procedure, and the description is omitted.
Further, the determination time of 100 ms in the constant diagnosis is an example, and may be determined in consideration of the inversion cycle of the signal to be diagnosed or the level determination cycle in the constant diagnosis.
[0026]
Next, a change in voltage at the time of disconnection diagnosis will be described with reference to an equivalent circuit diagram.
FIG. 3 is an equivalent circuit at the time of disconnection diagnosis for the signal line A.
Here, the resistance value of the output resistor 8a of the R / D conversion IC 1 is 1 kΩ, and the resistance value of the input resistor 9a of the CPU 2 is 1 MΩ. It is necessary that the diagnostic resistance 4a does not affect the signal flowing on the signal line A, so that the resistance value is set larger than the output resistance 8a and smaller than the input resistance 9a. Here, it is assumed that, for example, 100 kΩ is set.
[0027]
FIG. 4 is a diagram showing the voltage of each terminal in a normal state.
In a normal state, a signal from the output terminal PA of the R / D conversion IC1 can be transmitted to the input terminal P1 of the CPU 2, so that the output level of the diagnostic output terminal PD1 and the output terminal PA of the R / D conversion IC1 are There are two states, ie, the same state and a different state.
In the case of the same state, for example, when the Hi level is output, the voltage at the connection point c between the diagnostic resistor 4a and the signal line A is detected as 5V at the Hi level. Similarly, when the same Lo level is output, the voltage at the point c is detected as Lo level at 0V.
[0028]
When the output level of the output terminal PA is different from the output level of the diagnostic output terminal PD1, for example, when the output terminal PA outputs the Hi level, the voltage at the point c is 4.95V by calculation and is determined to be the same Hi level. .
When the output terminal PA outputs the Lo level, the voltage at the point c is 0.05 V by the calculation, and it is determined that the Lo level is the same.
Therefore, it can be seen that selecting the resistance value of the diagnostic resistor 4a to 100 kΩ does not affect signal transmission.
[0029]
FIG. 5 is a diagram illustrating the voltage of each terminal when a disconnection occurs between the output terminal PA and the connection point c.
When the output level of the output terminal PA is different from the output level of the diagnostic output terminal PD1, for example, when the output voltage of the output terminal PA is 5V and Hi level, the point c at the connection point c between the diagnostic resistor 4a and the signal line A The voltage is 0 V, and is detected as Lo level which is the same as the output level of the diagnostic output terminal PD1. Disconnection is detected.
When the output voltage of the output terminal PA is 0 V and at the Lo level, the voltage at the connection point c between the diagnostic resistor 4a and the signal line A is 5V, and is detected as the same Hi level as the output level of the diagnostic output terminal PD1. Similarly, disconnection can be detected.
[0030]
When the output level of the output terminal PA and the output level of the diagnostic output terminal PD1 are the same, the same voltage of 5 V or 0 V is applied to the connection point c even if there is a disconnection. Therefore, the occurrence of disconnection cannot be determined. However, in this case, when the output level of the diagnostic output terminal PD1 is changed to, for example, Lo level, if the voltage at the connection point c becomes zero and it is determined to be Lo level, it is possible to detect the disconnection.
[0031]
Further, in this embodiment, the diagnosis of the input terminals P1 to P6 of the CPU 2 is performed by the initial diagnosis, and the diagnosis of the output terminals PA, PB, PU, PV, PW, and PERR of the R / D conversion IC 1 is always performed by the diagnosis. However, by performing one cycle of the normal diagnosis together with the initial diagnosis, it is possible to diagnose the connection state of the signal line between the R / D conversion IC 1 and the CPU 2 before starting the normal control. The reliability of the signal to be read is further improved.
[0032]
As described above, according to the present embodiment, the terminal open failure of the R / D conversion IC 1 and the CPU 2 can be detected even for a signal line on which the potential on the abnormal side cannot be defined, and the reliability of the signal read by the CPU 2 can be detected. There is an effect that can be improved.
Further, it is possible to detect a terminal open failure on the CPU 2 side, which has been difficult to detect conventionally, and there is an effect that the reliability of a signal read by the CPU 2 can be further improved.
[0033]
Further, the terminal open failure on the R / D conversion IC 1 side can be diagnosed even in a state where the level of the signal line frequently changes in the normal control, and the reliability of the signal read by the CPU 2 is improved. There is also an effect.
In addition, since the terminal open failure of the R / D conversion IC 1 and the CPU 2 can be detected before the start of the normal diagnosis, it is necessary to rotate the motor as compared with the conventional method of diagnosing based on a combination of level changes of a plurality of signal lines. Since the detection can be performed without any problem, there is an effect that the reliability of the normal control can be improved.
In this embodiment, the description has been given of the combination of the R / D conversion IC 1 and the CPU 2. However, it is needless to say that the present invention can be applied to the transmission and reception of signals between two similar circuits.
In the present embodiment, Step 110, Step 120, Step 130, Step 140, Step 150, Step 190, Step 200, Step 210, Step 220, Step 230, and Step 240 constitute a disconnection detecting unit.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an embodiment.
FIG. 2 is a flowchart illustrating a flow of disconnection diagnosis.
FIG. 3 is an equivalent circuit at the time of disconnection diagnosis for a signal line A;
FIG. 4 is a diagram showing voltages at respective terminals in a normal state.
FIG. 5 is a diagram illustrating voltages at respective terminals when a disconnection occurs.
[Explanation of symbols]
1 R / D conversion IC (R / D converter)
2 CPU (rotation angle detection means)
4 (4a to 4f) Diagnostic resistor 5 Resistor 6 Motor 7 Resolver A, B, U, V, W, ERR, CS Signal line PA Output terminal PB Output terminal PU Output terminal PV Output terminal PW Output terminal PREE Output terminal PCS Input Terminal PD1 Diagnostic output terminal P1 Input terminal P2 Input terminal P3 Input terminal P4 Input terminal P5 Input terminal P6 Input terminal PD2 Output terminal

Claims (2)

An R / D converter that outputs a signal corresponding to the rotation angle of the rotating machine input from the resolver as a digital signal composed of Hi and Lo signals;
It is connected to the R / D converter via a signal line, receives a digital signal output from the R / D converter, and determines the rotation angle of the rotating machine based on Hi and Lo of the input digital signal. A rotation angle detection device having a rotation angle detection means for detecting, wherein an output resistance of the R / D converter is larger than an input resistance of the rotation angle detection means,
The rotation angle detecting means is provided with a diagnostic output terminal for outputting Hi and Lo signals,
A diagnostic resistor having a resistance higher than the output resistance of the R / D converter and lower than the input resistance of the rotation angle detecting means is connected between the diagnostic output terminal and the signal line;
The input signal of the rotation angle detecting means when the Hi signal is output from the diagnostic output terminal is Hi, and the input signal of the rotation angle detecting means when the Lo signal is output from the diagnostic output terminal is Lo. A disconnection detecting unit for determining that the output terminal of the R / D converter has a disconnection failure when a certain state continues for a predetermined time or more; When the output terminal of the R / D converter has high impedance, the disconnection detection unit outputs an Hi signal from the diagnostic output terminal, and the input signal of the rotation angle detection unit is not Hi; If the input signal of the rotation angle detecting means when the Lo signal is output from the diagnostic output terminal is not Lo, it is determined that the input terminal of the rotation angle detecting means has a disconnection failure. Item 2. A disconnection diagnosis device for the rotation angle detection device according to Item 1.

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