JP3491526B2 - IC chip abnormality detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a device for detecting an abnormality of a measuring device which measures one physical quantity and obtains two types of outputs, and more particularly to the two types of outputs. Is output from one IC chip. 2. Description of the Related Art A resolver for detecting a rotation angle of a rotor of a rotating machine such as an electric motor is known. The rotation angle detected by the resolver is used for controlling the current of the rotating machine. When a signal of a sine wave sinωt is input to the primary winding of the resolver, signals sinωtsinθ and sinωtcosθ modulated according to the motor rotation angle θ are respectively applied to two secondary windings arranged with a phase difference of 90 °. can get. The R / D converter (resolver / digital converter) calculates a rotation angle θ based on the output of the resolver and outputs the calculated rotation angle θ. In particular, in a certain type of R / D converter, the rotation angle θ is increasing (forward rotation) or decreasing (reverse rotation).
A signal that outputs both a signal indicating whether the rotation angle θ and a signal indicating the rotation angle θ itself is known. When the former output is used, the rotation angle θ is calculated by increasing or decreasing the rotation angle θ by the predetermined angle each time the motor rotates by a predetermined angle. In the case of using the latter output, since the value indicated by the output itself indicates the absolute value of the rotation angle θ, this output value may be used as it is as the rotation angle θ. [0003] When the latter, that is, a signal indicating the value of the rotation angle itself (hereinafter, referred to as an absolute value) is used as the rotation angle used for controlling the rotation machine, a CPU for controlling the rotation machine is used. The load on the (central processing unit) increases. C
In order to reduce the load on the PU, the former, that is, the rotation angle θ estimated by accumulating the change in the rotation angle from the reference value based on the signal indicating the information of the increase or decrease of the rotation angle may be used. However, in this method, since only the information of the change of the rotation angle is used, even if the calculated rotation angle is deviated from the actual rotation angle due to an abnormality of the R / D converter, the calculated rotation angle is calculated. The control is executed based on. Actually, there is a problem that the control cannot be established because the rotation angle used for the control is deviated from the actual rotation angle. The present invention has been made to solve the above-described problem, and a physical quantity obtained by accumulating a change from a previous detection value does not match an actual value of the physical quantity. It is an object of the present invention to provide a device capable of detecting such an abnormality. Another object of the present invention is to provide an apparatus for detecting an abnormality of an R / D converter such that the rotation angle of the rotating machine calculated based on the increase / decrease information of the rotation angle does not match the actual rotation angle. Aim. [0006] In order to solve the above-mentioned problems, an IC chip abnormality detection apparatus according to the present invention is provided with one physical quantity and a relative change value which is a change from a previous detection value. A device for detecting an abnormality of one IC chip that outputs two kinds of values, an absolute value that is an absolute value of the physical quantity, and a means for calculating an accumulated value obtained by accumulating the relative change values; Means for comparing the accumulated value with the absolute value, and determining that an abnormality has occurred in the IC chip when they do not substantially match. Further, the abnormality detection device for an R / D converter according to the present invention provides an increase / decrease signal indicating whether the rotation angle has increased or decreased by a predetermined angle based on an output signal of a resolver corresponding to the rotation angle of the rotating machine. And a device for detecting an abnormality of the R / D converter that outputs a signal indicating an absolute value of the rotation angle, wherein a means for calculating the rotation angle by accumulating the increase / decrease signal
Means for comparing the cumulatively obtained rotation angle with the absolute value of the rotation angle, and determining that an abnormality has occurred in the R / D converter when they do not substantially match. . Further, the voltage of the power supply of the R / D converter is set for a predetermined time.
Power status judgment to judge that the status is continuously lowered
Means for determining the drop in power supply voltage
If it is determined that the R / D converter is abnormal,
I do not know. [0008] Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of the apparatus of the present embodiment. The oscillator 10 outputs a reference signal sinωt, which
2 is applied to the primary coil. Voltages sinωtsinθ and sinωtcosθ in which the reference signal is modulated by the rotation angle θ of a rotating machine such as an electric motor are generated in two secondary coils arranged with a phase difference of 90 ° of the resolver 12, and these are output as resolver signals. Is done. In the processing of the resolver signal, only the phase poses a problem. Therefore, the reference signal and the resolver signal will be described with an amplitude of 1. The resolver signal is sent to an R / D converter 14, where it is multiplied by cos φ and sin φ by a multiplier 16 and subtracted by a subtracter 18 to obtain sinωtsin (θ−φ). The phase difference φ will be described later. This signal and the reference signal
sinωt is input to the detector 20, and the detector 20 outputs only the modulation component sin (θ−φ). The integrator 22 integrates the output sin (θ−φ) of the detector 20, and when this value exceeds a predetermined positive value, the voltage controlled oscillator 24 instructs to increase the value of the phase difference φ. Further, when the output of the integrator 22 is less than a negative predetermined value whose absolute value is equal to the positive predetermined value,
The voltage controlled oscillator 24 issues an instruction to decrease the value of the phase difference φ. The value of the 12-bit up / down counter 26 increases or decreases in response to an increase or decrease instruction of the voltage controlled oscillator 24. The value stored in the counter 26 represents the phase difference φ, and the phase difference φ is input to the multiplier 16 via a D / A converter (digital / analog converter) 28, and the above-described calculation is performed. The above circuits, ie, the multiplier 16 to the subtracter 18, the detector 20, the integrator 22, and the voltage controlled oscillator 2
4, a feedback circuit is formed up to the counter 26 and the D / A converter 28, and the calculation is repeated until the phase (θ−φ) becomes 0, that is, until the rotation angle θ matches the count value φ of the counter 26. . Therefore, after the feedback has converged, the count value φ of the counter 26
Represents the rotation angle θ. In this embodiment, the time required for the convergence of the counter value φ is about 1 ms.
It is. An encoder I / F (encoder interface) based on the lower 2 bits output of the counter 26
Outputs an A-phase signal and a B-phase signal representing the rotation direction of the rotating machine. These phase signals are square wave signals whose phases are shifted from each other by 90 °. When the phase of the A phase is advanced, it indicates that the rotating machine is rotating forward, and when the B phase is advanced, Indicates that it is reversed. The A-phase and B-phase signals are output each time the counter value φ is counted up or down. The outputs of all the bits of the counter 26 are sent to a zero determination unit 32. When it is determined that the counter 26 has become zero, a signal indicating the Z phase is output from the zero determination unit 32. . This Z-phase signal is output once per rotation of the rotating machine. On the other hand, a CPU 40 for controlling a rotating machine described later
Receives latch signal CS from latch circuit 34, latches value φ of counter 26 at this time, and outputs serial I / F
(Serial interface) 36. And
Data is output from serial I / F 36 according to clock signal CLK from CPU 40. The above R / D converter 14 is driven by power from an R / D converter power supply 38. The rotating machine control CPU 40 has a serial I / O
The output from F36 is stored in the absolute value data storage unit 42. The stored data is a counter value φ when a latch instruction is issued, and represents the rotation angle θ. When the rotating machine is started, the data φ in the absolute value data storage unit 42 is further transferred to the control data storage unit 44, and this is the initial value of the control rotation angle data ψ. The reading of data from the serial I / F 36 is performed every 2 ms in the present embodiment, and the absolute value data storage unit 4
2 is updated each time. On the other hand, the encoder I / F 46 of the CPU 40 receiving the above-mentioned A-phase, B-phase and Z-phase signals
The value of data ψ stored in the control data storage unit 44 is updated by increasing or decreasing based on the phases of the phase and B-phase signals.
That is, if the phase A is advanced with respect to the phase B, the data ψ is increased, and if the phase B is advanced, the data ψ is decreased. When the Z-phase signal is detected, the control data storage section 44 is cleared and the data ψ is set to 0. If each section functions normally, the count value φ of the counter 26 and the control rotation angle data ψ substantially match the actual rotation angle θ. Then, the CPU 40 controls the phase current of the rotating machine based on the data ψ. As described above, in this embodiment, if only the initial value is read out from the serial I / F 36, the rotation angle θ can be obtained only from the outputs of the encoder I / F 30 and the zero determination unit 32.
(= Data ψ) can be calculated. However, once the data ψ stored in the control data storage unit 44 deviates from the actual rotation angle θ for some reason, the deviation is not corrected until the Z-phase signal is received. For example,
If one of the A-phase and B-phase signal lines from the encoder I / F 30 is disconnected, the data ψ is fixed and does not match the rotation angle θ until the Z-phase signal is received thereafter. This is shown in FIG.
Is shown in FIG. 2 shows a case where one of the A-phase and B-phase signal lines is disconnected at time t1 while the rotating machine is rotating at a constant speed. After the time t1, the rotation angle θ increases, but the data ψ is stuck and there is a shift between them. Therefore, it becomes impossible to control the phase current of the rotating machine based on data ψ. Also, when the counter 26 does not count up or down normally, the data ψ does not represent the rotation angle θ. For example, if the data of a certain bit should remain at 0 where it should become 1 due to a carry during the count-up, the count value φ increases or decreases to match the rotation angle θ by the above-described feedback action. Decrease. This increase or decrease depends on the encoder I / F.
30 and outputs the A-phase and B-phase signals, based on which the data ψ is increased or decreased. This increase / decrease is not caused by a change in the rotation angle θ, but is caused by an internal process of the R / D converter 14 for matching the shifted count value φ to the rotation angle θ. By this processing, the data φ represents the rotation angle θ, while the data ψ deviates from the rotation angle θ. This shift is also Z
It is not resolved until the phase signal is received. FIG. 3 shows this failure mode. At time t2, “1”
When “111111” becomes “10000000”, the most significant bit does not change from 0 to 1 but becomes “00000000”.
00 ”and the data φ and data ψ. The data φ once becomes zero, but represents the actual rotation angle θ in about 1 ms due to the feedback action.
However, since the data φ is successively increased by the above-mentioned feedback action, it is determined that the rotating machine is rotating forward. Therefore, the data ψ increases and deviates from the rotation angle θ.
When the feedback converges and the data φ indicates the rotation angle θ, the deviation of the data ψ does not increase any more, but this deviation is not eliminated until the next Z-phase signal is received. In order to detect the occurrence of a failure as described above, the present embodiment employs a rotation angle abnormality determining unit 48.
Is provided. That is, the CPU 40 stores the data φ in the absolute value data storage 42 and the control data storage 44
And it is monitored whether or not these values match, and when they are substantially equal, it is determined that the R / D converter 14 functions normally and the data ψ appropriately represents the rotation angle θ. Conversely, when the deviation of the data ψ from the data φ is equal to or larger than a predetermined value, it is determined that the data ψ does not represent the rotation angle θ. When the abnormality is determined, the abnormality processing 50 is executed, and the rotating machine is stopped. When the voltage of the power supply 38 for the R / D converter is lowered, and when it is determined that the data φ in the absolute value data storage section 42 is not reliable, the above-described abnormality determination of the data ψ is not performed. When the power supply voltage drops,
Since it is considered that the R / D converter 14 is not operating normally, there is a possibility that neither the data φ nor the data 表 indicates the rotation angle θ, and these comparisons are meaningless. When the absolute value data φ is not reliable, there is no point in comparing the absolute value data φ with the control data ψ. Therefore, the abnormality determination at this time is not performed. The abnormality of the R / D converter power supply 38
The determination is made by the power supply abnormality determination unit 52 of the PU 40. Also,
Abnormality of the absolute value data φ is determined by the absolute value abnormality determining unit 54. The CPU 40 reads the data of the serial I / F 36 twice in succession, and determines that the absolute value data φ is normal when the two data substantially match. Actually, there is a slight time difference between the two data readings, so the two data are slightly different if the rotating machine is rotating. If there is a difference between the two data that is considered to be due to the rotation of the rotating machine, the read absolute value data φ is determined to be an abnormal value. FIG. 4 shows a flowchart relating to abnormality detection of the R / D converter of the present embodiment. This processing is performed periodically, that is, every 2 ms in this embodiment, and when the processing timing comes, the absolute value data φ of the rotation angle of the motor is read into the CPU 40 from the serial I / F 36 (S100). This reading is performed twice in succession. If the two values are substantially equal, the reading of the absolute value, that is, serial communication is determined to be normal, and if not substantially equal, it is determined to be abnormal (S102). . If there is an abnormality in the absolute value data φ, the abnormality counter is cleared (S104), and the abnormality determination by this processing is not performed. If it is determined that the data φ has been read normally, then R
It is determined whether the / D converter power supply 38 is in a normal state continuously for a predetermined time or more (S106). If the power supply 38 is not normal, the abnormality counter is cleared (S10
8), the abnormality determination by this processing is not performed. If the power supply 38 is normal, then the difference between the data φ and the data ψ is calculated,
It is determined whether this is equal to or greater than a predetermined value (S110).
If less than the predetermined value, the abnormality counter is cleared (S11
2) If the value is equal to or more than the predetermined value, the abnormality counter is incremented (S114). Then, it is determined whether the abnormality counter is equal to or greater than a predetermined value (S116). If the abnormality counter is equal to or greater than the predetermined value, it is determined that the R / D converter 14 or its power supply 38 has an abnormality (S118). If the abnormality counter is less than the predetermined value, the abnormality determination is suspended, and after a predetermined time has elapsed, the present flow is executed again. As described above, the data φ directly indicating the value of the rotation angle θ output from the R / D converter 14 and the R / D
The data ψ representing the rotation angle θ calculated based on the signal indicating whether the rotation is forward or reverse output from the converter 14 is monitored, and if they do not match, the failure of the R / D converter 14 is determined. If a failure is determined, the control of the rotating machine is stopped. However, if the initial setting is completed, the rotating machine can be controlled without the data φ, and if the data φ is determined to be abnormal, the control shown in FIG. Do not cancel rotating machine control. Also, R
Even when the power supply 38 for the / D converter is abnormal, the R /
Since the D converter 14 itself is not abnormal, the control of the rotating machine is not directly stopped. Data φ
For the abnormality of the power supply 38 and the abnormality of the power supply 38, it is determined by another monitoring flow whether or not the control of the rotating machine is stopped.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a schematic configuration of the present embodiment. FIG. 2 is a diagram showing changes in rotation angle data ψ calculated based on information on normal rotation and reverse rotation of a rotating machine and data φ indicating an actual value of the rotation angle when an abnormality occurs. FIG. 3 is a diagram showing changes in rotation angle data ψ calculated based on information on normal rotation and reverse rotation of a rotating machine and data φ indicating an actual value of the rotation angle when an abnormality occurs. FIG. 4 is a chart showing a control flow of the embodiment. [Description of References] 12 resolver, 14 R / D converter, 26 up / down counter (counter), 40 CPU, 42
Absolute value data storage unit, 44 control data storage unit, 4
8 Abnormal rotation angle determination unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01D 5/00-5/62 H02K 24/00 G01D 18/00-21/02

Claims (1)

(57) [Claim 1] An increase / decrease signal indicating whether the rotation angle has increased or decreased by a predetermined angle, based on an output signal of one resolver corresponding to the rotation angle of the rotating machine, and a rotation signal. An apparatus for detecting an abnormality of an R / D converter that outputs a signal indicating an absolute value of an angle, a unit that calculates a rotation angle by accumulating the increase / decrease signal, Means for comparing the absolute value of the rotation angle with the absolute value of the rotation angle to determine that an abnormality has occurred in the R / D converter when they do not substantially coincide with each other;
Power state determining means for determining that the
A, means for determining abnormality of the R / D converter, before
The power supply state determining means determines that the power supply voltage has dropped.
In the case, the abnormality determination is not performed . The abnormality detection device of the R / D converter.