Rotation angle sensor abnormality diagnosis device

Abstract

To provide an abnormality diagnostic device of a rotation angle sensor of which abnormality detection accuracy is improved.SOLUTION: An abnormality diagnostic device 400 determines the presence or absence of an abnormality of a rotation angle sensor (resolver) 320 on the basis of a sine signal and a cosine signal which are output from the rotation angle sensor 320 provided in a motor 300. The abnormality diagnostic device includes: a high-speed data acquisition section 401 that acquires a sine signal and a cosine signal in a sampling period of not smaller than six times of a period of an excitation signal input to the rotation angle sensor 320; a square sum calculation section 403 that respectively squares and adds data on the sine signal and the cosine signal acquired in the high-speed data acquisition section 401 to calculate a square sum calculation result; and an abnormality determination section 405 that determines the presence or absence of an abnormality of the rotation angle sensor 320 on the basis of a calculation result of the square sum calculation section 403.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an abnormality diagnosis device for a rotation angle sensor. [Background technology]

[0002] In recent years, with the electrification of automobiles, vehicles using permanent magnet synchronous motors (PMSMs) for the main engine and auxiliary equipment (brakes, power steering, etc.) have become widespread. Information from rotation angle sensors is essential for controlling PMSMs. To improve the reliability of rotation angle sensors, it is necessary to ensure the validity of the rotation angle sensor signals when using their values.

[0003] Patent Document 1 describes a technology for detecting a phase shift with an excitation signal, which is an input signal of a resolver (rotation angle sensor), based on the values ​​of the excitation component, sine wave component, and cosine wave component sampled at multiple points in time during one cycle of the excitation signal. The phase shift is detected by detecting the presence or absence of a cosine wave component at a predetermined angle of the excitation signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-190533 Summary of the Invention [Problem to be solved by the invention]

[0005] An excitation signal is input to the resolver, but the technology described in Patent Document 1 is based on the premise that there is no abnormality in the period of the excitation signal of the resolver.

[0006] However, it is necessary to detect whether there is an abnormality in the period of the resolver excitation signal, ensure the validity of the rotation sensor signal, and further improve the reliability of the rotation angle sensor.

[0007] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to realize an abnormality diagnosis device for a rotation angle sensor with improved accuracy in detecting abnormalities in the rotation angle sensor. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention is configured as follows.

[0009] An abnormality diagnosis device for a rotation angle sensor that determines whether or not there is an abnormality in a rotation angle sensor provided in a motor based on a sine signal and a cosine signal output from the rotation angle sensor, comprising: a data acquisition unit that acquires the sine signal and the cosine signal output from the rotation angle sensor; Note a square sum calculation unit that squares and adds the data of the sine signal and the cosine signal obtained by the data acquisition unit, and calculates a square sum calculation result; and an abnormality determination unit that determines whether or not there is an abnormality in the rotation angle sensor based on the calculation result of the square sum calculation unit, and the abnormality determination unit determines whether or not there is an abnormality in the rotation angle sensor based on the square sum calculation result, the sine signal and the cosine signal is abnormal, and based on the square sum calculation result, it is determined whether the amplitude values ​​of the sine signal and the cosine signal are abnormal using the peak values ​​obtained. [Effects of the Invention]

[0010] According to the present invention, it is possible to realize an abnormality diagnosis device for a rotation angle sensor with improved accuracy in detecting abnormalities in the rotation angle sensor. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram of a motor control device to which a resolver, which is a rotation angle sensor, is connected and which is provided with an abnormality diagnosis device according to an embodiment of the present invention; [Figure 2] 1 is a diagram showing a schematic configuration of an abnormality diagnosis device 400 according to an embodiment of the present invention. [Figure 3] 10A and 10B are explanatory diagrams of a method for storing buffer data saved in a data buffer unit. [Figure 4] 1 is a diagram showing the relationship between an excitation signal and amplitude-modulated sine and cosine components to explain the principles of the present invention; FIG. [Figure 5] 10 is a graph for explaining the square sum characteristics of a sine component and a cosine component. [Figure 6] 10 is a graph illustrating the relationship between an excitation signal and a square sum signal. [Figure 7] 10 is a graph illustrating the relationship between an excitation signal and a square sum signal. [Figure 8] 4 is a flowchart illustrating the operation of an abnormality determination unit in the abnormality diagnosis device. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment of the present invention is not limited to the examples described below, and various modifications are possible within the scope of the technical concept. [Example]

[0013] FIG. 1 is a schematic diagram of a motor control device 100 to which a resolver 320, which is a rotation angle sensor, is connected by an abnormality diagnosis device 400 according to an embodiment of the present invention.

[0014] In FIG. 1, motor control device 100 is connected to motor 300. Motor drive device 100 has a current control unit 110, an inverter 130, a rotational position detection unit 150, and an excitation unit 160. Battery 200 is a DC voltage source for motor drive device 100. DC power stored in battery 200 is converted into three-phase AC power with variable voltage and variable frequency by inverter 130 of motor drive device 100. Inverter 130 supplies this three-phase AC power to motor 300.

[0015] The motor 300 is a synchronous motor that is rotationally driven by a supply of three-phase AC power. A resolver 320 is attached to the motor 300 as a rotation angle sensor for the rotor 310 in order to control the phase of the three-phase AC voltage in accordance with the phase of the induced voltage of the motor 300.

[0016] The resolver 320 receives an excitation signal (sinωt) from the excitation unit 160 and outputs amplitude-modulated two-phase signals Sn1 (sine wave signal (sinθsinωt)) and Cn1 (cosine wave signal (cosθsinωt)) that are out of phase with each other by 90° (θ: motor rotation angle).

[0017] The current control unit 110 generates a drive signal generated by pulse width modulation (PWM) so as to follow a current command value generated by a higher-level control device (not shown). The current control unit 110 calculates three-phase motor voltage command values ​​corresponding to the motor current values ​​(Iu, Iv, Iw) detected by the current sensor 170 and the rotation angle θ of the motor 300 detected by the rotation position detection unit 150.

[0018] The drive signals described above control on / off of semiconductor switch elements that constitute the main circuit of the inverter 130, so that the inverter 130 outputs three-phase voltages (Vu, Vv, Vw) in accordance with the motor voltage command.

[0019] The signal input to the rotational position detection unit 150 in response to the two output signals (Sn1, Cn1) of the resolver 320 is sampled at timings that are odd multiples of π / 2 in electrical angle in the excitation signal (sinωt) (π / 2, 3π / 2, 5π / 2, ...), thereby removing the modulation component.

[0020] The rotational position detection unit 150 calculates the rotation angle θ of the motor 300 based on the two-phase signal from which the modulation component has been removed. The abnormality diagnosis device 400 receives the output signals of the resolver 320 and detects the presence or absence of an abnormality in the resolver 320 based on these signals.

[0021] When the abnormality diagnostic device 400 detects an abnormality, it outputs an abnormality determination signal J1 that notifies a higher-level control device (not shown) of the abnormality in the resolver 320.

[0022] FIG. 2 is a diagram showing a schematic configuration of an abnormality diagnosis device 400 according to an embodiment of the present invention.

[0023] 2, two amplitude-modulated output signals Sn1 and Cn1 from the resolver 320 are input to the abnormality diagnosis device 400. The two output signals Sn1 and Cn1 are first acquired by AD conversion in an AD conversion unit (high-speed data acquisition unit) 401 at a sampling period six or more times the period of the excitation signal.

[0024] A sampling number of 6 times or more is a value to ensure the minimum number of samples required to measure the peak period in the square sum calculation described below, but in order to improve the accuracy of waveform reproduction, it may preferably be 10 times or more.

[0025] The data Sn2 and Cn2 sampled by the AD conversion unit 401 is stored for one excitation period in the data buffer unit 402. At this time, the buffer unit 402 also stores the time of AD conversion, for example, the free-running timer value T1, together with each signal.

[0026] As will be described later, the buffer data stored in the data buffer unit 402 can be managed by index by storing each data as an array.

[0027] The two output signals Sn2B and Cn2B from the data buffer unit 402 are subjected to a square sum calculation for each index by a square sum calculation unit 403, and the data is similarly stored as an array.

[0028] The peak index detection unit 404 extracts an amplitude peak from the data SQ1 obtained by the square sum calculation by the square sum calculation unit 403. The free-running timer value T1 stored in the data buffer unit 402 is output to the peak index detection unit 404 as T1B.

[0029] As an example of a method for detecting an amplitude peak, the following peak value search method may be used.

[0030] That is, in the peak value search method, for example, three pieces of data are extracted using consecutive indexes, and when the data are designated as data 1, data 2, and data 3, data 2 that satisfies the following condition (1) may be selected: Condition (1): Data 1 < Data 2 & Data 2 > Data 3 Using the data index obtained under condition (1), amplitude peak values ​​Pk1 and Pk2, which are consecutive peak values ​​for calculating the period, are extracted. AD conversion time data Tpk1 and Tpk2 at which the amplitude peak values ​​occurred are also extracted.

[0031] The amplitude peak value Pk1, the amplitude peak value Pk2, the AD conversion time data Tpk1, and the AD conversion time data Tpk2 are output to the abnormality determination unit 405. Then, the abnormality determination unit 405 derives the period (square sum period fsqr) of the square sum data SQ1 using the following equation (1).

[0032] Sum-of-squares period fsqr=1 / (Tpk2-Tpk1) (1) The abnormality determination unit 405 compares the square sum period fsqr with the excitation period expected by the system, determines whether or not there is an abnormality, and outputs an abnormality determination result J1. The abnormality determination result J1 can be notified by an appropriate display device or the like.

[0033] FIG. 3 is an explanatory diagram of a method for storing buffer data saved in the data buffer unit 402. As shown in FIG.

[0034] A predetermined amount of data Sn2 sampled by the AD conversion unit 401 is stored in chronological order in a sine component table 501. An index is assigned to each piece of data to facilitate data search. When the buffer data is filled with a predetermined amount of data, the oldest data is overwritten and saved in chronological order.

[0035] Similarly, a predetermined amount of data Cn2 sampled by the AD conversion unit 401 is stored in a cosine component table 502 in time series.

[0036] Furthermore, the time stamps sampled by the AD conversion unit 401 are stored in a time series in an AD conversion time stamp table 503 for a predetermined amount of data.

[0037] Furthermore, the sum-of-squares calculation unit 403 stores a predetermined amount of data of the sum-of-squares data SQ1 of the sine and cosine components for each index in a sum-of-squares table 504 in time series.

[0038] In this embodiment, the size of data stored in the data buffer unit 402 is set to 10, but in actual operation, the size may be changed according to the number of AD conversion samples in one excitation period.

[0039] 4 is a diagram illustrating the relationship between the excitation signal (sinωt) and the amplitude-modulated sine component Sn1 and cosine component Cn1, in order to explain the principle of the present invention. Fig. 4 shows an enlarged view of the amplitude-modulated sine component Sn1 and cosine component Cn1 for several periods of the excitation signal when the excitation signal (sinωt) is applied to the resolver 320, in an arbitrary time period.

[0040] In Fig. 4, the excitation signal frequency and the frequencies of the amplitude-modulated sine component Sn1 and cosine component Cn1 are basically the same frequency due to the circuit configuration (although there may be a slight phase difference).

[0041] Therefore, by observing the frequencies of the sine component Sn1 and the cosine component Cn1, the soundness of the excitation cycle should be observable.

[0042] However, as shown in the enlarged waveform in Figure 4, there are sections where the amplitude is small depending on the observation timing (the amplitude of the sine component Sn1 is small), so it is difficult or impossible to observe the frequency of the waveform in these sections.

[0043] In the example shown in FIG. 4, observation is performed at a timing when the amplitude of the sine component Sn1, that is, the sine component, becomes small, but there is also a timing when the amplitude of the cosine component Cn1 becomes small in a similar manner.

[0044] Next, the square sum characteristics of the sine component Sn1 and the cosine component Cn1 of the two amplitude modulated waves output from the resolver 320, which is the basis of the present invention, will be described.

[0045] FIG. 5 is a graph for explaining the square sum characteristics of the sine component Sn1 and the cosine component Cn1.

[0046] The excitation signal (sinωt) input to the resolver 320 is set to a predetermined amplitude and a predetermined frequency.

[0047] On the other hand, the sine component Sn1 and cosine component Cn1 of the signal that is amplitude modulated by the excitation signal (sinωt) and output from the resolver 320 have waveforms whose amplitudes vary according to the angular position of the resolver 320.

[0048] Each signal component has a sine component Sn1=sinθsinωt and a cosine component Cn1=cosθsinωt.

[0049] In particular, the sine component Sn1 has an amplitude of approximately 0 when the angle of the resolver 320 is 0 degrees, 180 degrees, etc. Conversely, the cosine component Cn1 has an amplitude of approximately 0 when the angle of the resolver 320 is 90 degrees, 270 degrees, etc. This is in accordance with the amplitudes of the sine and cosine components of the angle.

[0050] On the other hand, a signal Sqr1 (a result of the square sum calculation) calculated by taking the square sum of the sine component Sn1 and the cosine component Cn1 has components expressed by the following equation (2).

[0051] Sqr1=(sinωt) 2 (sinθ 2 +cosθ 2 ) ···(2) The following formula (3) holds true from the basic formula of trigonometric functions.

[0052] Sqr1=(sinωt) 2 ···(3) From the above equation (3), unlike the sine component Sn1 and the cosine component Cn1, the sum-of-squares signal Sqr1 has a sine wave characteristic of constant amplitude regardless of the angle of the resolver 320.

[0053] Furthermore, as shown in Figures 6 and 7, the square sum signal Sqr1 is a sine wave of constant amplitude synchronized (linked) with the excitation signal (sinωt), and since it is a double angle equation, the frequency fsqr of the signal Sqr1 is exactly twice the excitation signal frequency fexc.

[0054] The present invention utilizes a signal Sqr1 that has twice the period of the excitation signal and is the sum of squares of a constant amplitude to diagnose abnormalities in the resolver 320, which is a rotation angle sensor.

[0055] FIG. 8 is a flowchart showing the operation of the abnormality determination unit 405 in the abnormality diagnostic device 400.

[0056] In step S1 of FIG. 8, the abnormality determination unit 405 starts an operation to detect whether or not the resolver 320 has an abnormality.

[0057] Next, in step S2, the abnormality determination unit 405 takes in the amplitude peak value Pk1 and the amplitude peak value Pk2 acquired by the peak index detection unit 404.

[0058] Next, in step S3, the abnormality determination unit 405 acquires the AD conversion time tpk1 and the AD conversion time tpk2 (corresponding to the AD conversion time data Tpk1 and the AD conversion time data Ttpk2) according to the index of the amplitude peak value Pk1 and the amplitude peak value Pk2 acquired by the peak index detection unit 404.

[0059] Next, in step S4, the abnormality determination unit 405 calculates the square sum signal period fsqr from the AD conversion times tpk1 and tpk2 acquired in S3 (the calculation formula is described above).

[0060] Next, in step S5, the abnormality determination unit 405 determines whether the value of half the square sum signal period fsqr acquired in step S4 is less than the upper limit value fexcmax of the excitation signal period input to the resolver 320 from the excitation unit 160 or exceeds the lower limit value fexcmin, thereby determining whether there is an abnormality in the period of the excitation signal.

[0061] If the condition is met in step S5, it is determined in step S6 that there is no abnormality in the excitation signal period, and the period abnormality flag is set to 0 (no abnormality).

[0062] On the other hand, if the condition is not met in step S5, it is determined in step S7 that there is an abnormality in the excitation signal period, and the period abnormality flag is set to 1 (abnormal).

[0063] Furthermore, in step S8, the abnormality determination unit 405 determines whether the amplitude peak value Pk1 or the amplitude peak value Pk2 of the square sum signal acquired in step S2 is less than the upper limit value Pkmax or more than the lower limit value Pkmin, and determines whether there is an abnormality in the amplitude values ​​of the output signals Sn1 and Cn1 of the resolver 320.

[0064] If the above condition is met in step S8, the amplitude abnormality flag is set to 0 (no abnormality) in step S9, and the series of operations ends.

[0065] On the other hand, if the above condition is not met in step S8, the amplitude abnormality flag is set to 1 (abnormality present) in step S10, and the series of operations is stopped.

[0066] Note that steps S5 to S7 and steps S8 to S10 may be completed independently.

[0067] Furthermore, the abnormality determination J1 of the abnormality determination unit 405 can be displayed on an appropriate display device (not shown).

[0068] As described above, according to the present invention, the output signals Sn1 and Cn1 of the resolver 320, which is a rotation angle sensor, are summed by squares to obtain sum-of-squares data, and the peak values ​​Pk1 and Pk2 of the sum-of-squares data are detected to determine whether the obtained peak period is abnormal, and also determine whether the peak value Pk1 or the peak value Pk2 is abnormal.

[0069] Therefore, it is possible to realize an abnormality diagnosis device for a rotation angle sensor with improved accuracy in detecting abnormalities in the rotation angle sensor.

[0070] Furthermore, by calculating the square sum of the output signals Sn1 and Cn1 of the resolver 320 to obtain a square sum signal, it is possible to obtain sine waves and cosine waves of a predetermined amplitude regardless of the angular position. This makes it possible to determine whether or not there is an abnormality in the excitation signal, sine wave signal, and cosine signal regardless of the angular position.

[0071] In the above-described embodiment, the period of the excitation signal sinωt is calculated from the peak values ​​Pk1 and Pk2 of the square sum signal, but it is also possible to detect the zero value of the square sum signal and calculate the period of the zero value as the period of the excitation signal sinωt. [Explanation of symbols]

[0072] 100 Motor drive device, 110 Current control section, 130 Inverter, 150 Rotation position detection section, 160 Excitation section, 200 Battery, 300 Motor, 310 Rotor, 320 Resolver, 400 Abnormality diagnosis device, 401 AD conversion section, 402 Data buffer section, 403 Square sum calculation section, 404 Peak index detection section, 405 Abnormality determination section, 501 Sine component table, 502 Cosine component table, 503 AD conversion timestamp table, 504 Square sum table

Claims

[Claim 1] 1. A rotation angle sensor abnormality diagnosis device for determining whether or not an abnormality exists in a rotation angle sensor provided in a motor based on a sine signal and a cosine signal output from the rotation angle sensor, a data acquisition unit that acquires the sine signal and the cosine signal output from the rotation angle sensor; a square sum calculation unit that squares and adds the sine signal data and the cosine signal data obtained by the data acquisition unit, and calculates a square sum calculation result; an abnormality determination unit that determines whether or not there is an abnormality in the rotation angle sensor based on the calculation result of the square sum calculation unit; Equipped with The abnormality determination unit determining whether the periods of the sine signal and the cosine signal are abnormal based on the peak period or the period of the zero value obtained based on the result of the square sum calculation; The rotation angle sensor abnormality diagnostic device is characterized in that it determines whether the amplitude values ​​of the sine signal and the cosine signal are abnormal or not based on the peak value obtained from the result of the square sum calculation.

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