JP5621758B2 - Short-circuit detection device - Google Patents

Description

  The present invention relates to a short-circuit detection device applied to a signal detection device in which each of a plurality of secondary coils magnetically coupled to a primary coil to which an alternating voltage signal is input is a voltage detection target.

  2. Description of the Related Art Conventionally, there is known a signal detection device for a resolver that includes a primary coil that rotates with a rotor of a rotating machine and a pair of secondary coils. Specifically, in this device, first, an AC voltage signal is input to the primary coil. And the voltage signal of each both ends of a pair of secondary side coil induced by the magnetic flux which generate | occur | produces with a primary side coil is detected, and the rotation angle (electrical angle) of a rotor is based on a detected pair of voltage signal. To detect.

  Here, each of the primary coil and the pair of secondary coils included in the resolver is normally insulated from each other. However, if a short circuit occurs between these coils, the detection accuracy of the rotation angle of the rotor may be reduced.

  In order to solve such a problem, a technique for detecting an abnormality such as a short circuit between a primary side coil and a secondary side coil is known, as can be seen in Patent Document 1 below. Specifically, in this technique, first, each multiplication output is obtained by multiplying the two-phase output signals output from the pair of secondary coils. Then, the maximum value of the added value of each multiplication output is detected, and the abnormality is detected based on a comparison between the detected maximum value and a preset set value.

  Further, as a technique for detecting a short circuit between coils, there is a technique found in Patent Document 2 below. Specifically, in this technique, a bias is applied to each of the primary side coil and the pair of secondary side coils, and the resolver is based on a comparison between each ground direct current potential of the pair of secondary side coils and a predetermined threshold value. It is determined whether or not a short circuit has occurred between at least a pair of the primary coil and the secondary coil provided.

Japanese Patent No. 3588499 Japanese Patent No. 4122606

  By the way, when the short-circuit between the primary side coil and the secondary side coil occurs, the degree of decrease in the detection accuracy of the rotation angle by the signal detection device is reduced. It has been investigated by the inventor that it is greater than the degree. This is because an AC voltage signal is input to the primary coil.

  Based on such circumstances, the present inventor considered performing fail-safe according to the type of short circuit. In this case, although a technique for determining which one of the short-circuit between the primary side coil and the secondary side coil and the short-circuit between the secondary side coils has occurred is described in Patent Documents 1 and 2 above. With this technology, the type of short circuit cannot be determined.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to set each of a plurality of secondary coils magnetically coupled to a primary coil to which an AC voltage signal is input as a voltage detection target. To provide a short-circuit detection device that is applied to a signal detection device that can determine which one of a short circuit between a primary coil and a secondary coil and a short circuit between secondary coils occurs. is there.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

1st invention is applied to the signal detection apparatus which makes each of the some secondary side coil magnetically coupled with the primary side coil into which an alternating voltage signal is input voltage detection object, and direct-current potential with respect to a reference potential is said Bias applying means for applying a bias to each of the primary side coil and the secondary side coil, and a plurality of the secondary side coils, so that the primary side coil and the secondary side coil are different from each other. A short circuit that performs processing to determine which one of the short circuit between the primary side coil and the secondary side coil and the short circuit between the secondary side coils occurs based on the direct current potential with respect to each of the reference potentials. And a discriminating means.

  In the above invention, by providing the bias applying means, the DC potential with respect to the reference potential is made different between the primary side coil and the secondary side coil. According to such a configuration, the DC potential of the secondary side coil in which the short circuit has occurred is changed from the DC potential of the secondary side coil before the short circuit occurs, and a short circuit between the primary side coil and the secondary side coil occurs. A group of DC potentials of the plurality of secondary coils and a group of DC potentials of the plurality of secondary coils when a short circuit between the secondary coils occurs are different. That is, according to the group of DC potentials, the type of short circuit can be determined. For this reason, in the above invention, based on the direct current potential with respect to the reference potential of each of the plurality of secondary coils, any one of the short circuit between the primary coil and the secondary coil and the short circuit between the secondary coils. It can be determined whether it has occurred.

According to a second invention, in the first invention, the plurality of secondary coils are a pair of secondary coils, and the bias applying means has a pair of DC potentials with respect to the reference potential of the primary coils. A bias is applied to each of the primary side coil and the secondary side coil so as to be sandwiched between a DC potential with respect to the reference potential of the secondary side coil of the secondary side coil, and among the pair of secondary side coils, The higher DC potential with respect to the reference potential is defined as a high potential side coil, the remainder is defined as a low potential side coil, and a logical "" is determined based on a comparison between the DC potential with respect to the reference potential of the high potential side coil and the first threshold voltage. Based on a first comparator that outputs a signal of either “H” or logic “L”, and a comparison between the DC potential of the low potential side coil with respect to the reference potential and the second threshold voltage, the logic “H” And A second comparator that outputs any signal of logic “L”, wherein the first threshold voltage is the reference of the high potential side coil when no short circuit of the high potential side coil occurs. Is set to a value that is lower than the DC potential with respect to the potential and higher than the DC potential with respect to the reference potential of the high potential side coil when a short circuit between the primary side coil and the high potential side coil occurs, The second threshold voltage is higher than the DC potential with respect to the reference potential of the low potential side coil when the low potential side coil is not short-circuited, and between the primary side coil and the low potential side coil When the short circuit occurs, the low potential side coil is set to a value lower than the direct current potential with respect to the reference potential, and the short circuit determination means is a double of the first comparator and the second comparator. Based on the output signal, and performs processing for the discrimination.

  In the above-described invention, the primary side coil is arranged such that the DC potential with respect to the reference potential of the primary side coil is sandwiched between the DC potentials with respect to the reference potential of the pair of secondary side coils (high potential side coil and low potential side coil). A bias is applied to each of the high potential side coil and the low potential side coil. Then, the first threshold voltage of the first comparator and the second threshold voltage of the second comparator are set in the above manner.

  According to such a configuration, it is possible to invert the logic of the output signal of the comparator corresponding to the one where the short circuit has occurred in the secondary coil. Specifically, when the short circuit between the high potential side coil and the low potential side coil occurs based on the logic of the output signals of both the first and second comparators when no short circuit occurs, the outputs of both of these comparators The logic of the signal will be inverted. When the short circuit between the primary side coil and the high potential side coil occurs, only the logic of the output signal of the first comparator is inverted, and when the short circuit between the primary side coil and the low potential side coil occurs, the second Only the logic of the output signal of the comparator is inverted. According to the above invention, the type of short circuit can be easily and accurately determined.

According to a third invention, in the first or second invention, the reference potential is a ground potential of the signal detection device, and the bias applying means is configured such that a DC potential with respect to the ground potential is equal to the primary coil and the 2 A bias is applied to each of the primary side coil and the secondary side coil so that the secondary side coil does not become 0, and the short-circuit determining means sets the DC potential to the ground potential of the secondary side coil. Based on this, a process for determining whether or not a ground fault has occurred in the secondary coil is further performed.

  In the above invention, a bias is applied to each of the coils so that the DC potential with respect to the ground potential does not become zero in each of the primary side coil and the secondary side coil. According to such a configuration, when a ground fault occurs in the secondary side coil, the DC potential of the secondary side coil becomes the ground potential, and when the ground fault occurs in the secondary side coil, The DC potential of the secondary coil when the coils are short-circuited can be made different. For this reason, in the said invention, it can be judged whether the ground fault has arisen in the secondary side coil based on the DC potential with respect to the grounding potential of a secondary side coil.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the bias applying means is configured such that a direct current potential with respect to the reference potential of each of the primary side coil and the secondary side coil is the signal detection device. A bias is applied to each of the primary side coil and the secondary side coil so that the positive side potential of the direct current power source of the secondary side power source does not become, and the short circuit determination means sets the direct current potential to the reference potential of the secondary side coil. Based on the above, it is further characterized in that a process of determining whether or not a short circuit between the secondary coil and the positive electrode side of the DC power supply has occurred is further performed.

  In the above-described invention, a bias is applied to each of the coils so that the DC potential with respect to the reference potential of each of the primary side coil and the secondary side coil does not become the positive side potential of the DC power source of the signal detection device. According to such a configuration, the DC potential of the secondary coil when the secondary coil and the positive electrode side of the DC power source are short-circuited is made the positive electrode side potential of the DC power source, and a power fault occurs. The DC potential of the secondary side coil and the DC potential of the secondary side coil when a short circuit between the coils occurs can be made different. For this reason, in the said invention, it can be judged whether the power fault of the secondary side coil has arisen based on the DC potential with respect to the reference potential of the secondary side coil.

1 is a system configuration diagram according to a first embodiment. FIG. The figure which shows the outline | summary of the short circuit discrimination | determination process concerning the embodiment. The figure which shows an example of the output state of the resolver signal at the time of normal time and a short circuit occurrence. The system block diagram concerning 2nd Embodiment. The figure which shows the outline | summary of the short circuit discrimination | determination process concerning the embodiment. The system block diagram concerning 3rd Embodiment. The figure which shows the outline | summary of the short circuit discrimination | determination process concerning the embodiment. The system block diagram concerning 4th Embodiment. The figure which shows the outline | summary of the short circuit discrimination | determination process concerning the embodiment. The system block diagram concerning 5th Embodiment. The figure which shows the outline | summary of the short circuit discrimination | determination process concerning the embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a short-circuit detection device according to the present invention is applied to an electric vehicle on which a signal detection device for a one-phase excitation two-phase output type resolver is mounted will be described with reference to the drawings.

  FIG. 1 shows a system configuration according to the present embodiment.

  As shown in the figure, the primary coil 10 rotates integrally with a rotor 12a of a motor generator 12 as an in-vehicle main machine. One end of the primary coil 10 is connected to the excitation circuit 14 via a terminal R1, and the other end is grounded via a terminal R2.

  An AC voltage signal (excitation signal Sc) from the excitation circuit 14 is input to the primary coil 10. The magnetic flux generated in the primary coil 10 by the excitation signal Sc links the pair of secondary coils 16 and 18. At this time, the relative arrangement relationship between the primary coil 10 and the pair of secondary coils 16 and 18 periodically changes according to the rotation angle θ of the rotor 12a. As a result, the number of flux linkages of the secondary coils 16 and 18 changes periodically. In the present embodiment, the geometric arrangement of the pair of secondary coils 16 and 18 and the primary coil 10 is set to be different from each other, whereby the voltage generated in each of the secondary coils 16 and 18 is changed. The phases are shifted from each other by “π / 2”. As a result, the output voltages of the secondary coils 16 and 18 become modulated waves obtained by modulating the excitation signal Sc with the modulated waves cos θ and sin θ, respectively. Specifically, when the excitation signal Sc is “sin ωt”, the modulated waves are “cos θ × sin ωt” and “sin θ × sin ωt”, respectively.

  Incidentally, in this embodiment, hereinafter, the pair of modulated waves will be referred to as a resolver signal. The secondary coil 16 is referred to as a “secondary COS coil”, and the secondary coil 18 is referred to as a “secondary SIN coil”.

  Both ends of the secondary COS coil 16 are connected to the differential amplifier circuit 20 via terminals C1 and C2. The differential amplifier circuit 20 has a function of converting the output voltage of the secondary side COS coil 16 into a predetermined value.

  On the other hand, both ends of the secondary SIN coil 18 are connected to the differential amplifier circuit 22 via terminals S1 and S2. The differential amplifier circuit 22 has a function of converting the output voltage of the secondary SIN coil 18 into a predetermined value.

  Each of the output voltages voltage-converted by these differential amplifier circuits 20 and 22 is input to an R / D converter 24 (resolver digital converter). The R / D conversion unit 24 has a function of calculating the rotation angle θ (electrical angle) of the rotor 12a by converting the resolver signal as an analog signal into a digital signal.

  The electrical angle as a digital signal calculated by the R / D converter 24 is taken into a microcomputer (microcomputer 26). Specifically, the microcomputer 26 acquires a digital signal output from the R / D conversion unit 24 at a predetermined sampling period. The predetermined sampling period is determined by a pulse output from the input circuit 28. Specifically, the input circuit 28 pulses at a timing (zero cross timing) at which the excitation signal Sc output from the excitation circuit 14 intersects with a reference potential (such as a vehicle body potential, such as a ground potential of the signal detection device: GND potential). Has a function of outputting.

  Next, a short circuit determination process according to the present embodiment will be described. This processing is repeatedly executed by the microcomputer 26 at a predetermined cycle, for example, and the primary side coil 10 and the secondary side COS coil 16 are short-circuited, the primary side coil 10 and the secondary side SIN coil 18 are short-circuited, and the secondary side This is a process of determining which one of the short circuits between the side COS coil 16 and the secondary SIN coil 18 has occurred. In order to perform this process, in this embodiment, the DC potential with respect to the GND potential is biased to these coils so that the primary side coil 10, the secondary side COS coil 16, and the secondary side SIN coil 18 are different from each other. The structure which applies is adopted. When these coils are arranged in order from the highest DC potential, the secondary COS coil 16, the secondary SIN coil 18, and the primary coil 10 are obtained. Hereinafter, the configuration on the secondary side for realizing such a configuration will be described in detail.

  A series connection body of resistors 30 and 32 is connected in parallel to the secondary side COS coil 16, and a voltage is applied to a connection point of these resistors by a constant voltage power supply 34. In addition, a series connection body of resistors 36 and 38 is connected in parallel to the secondary side COS coil 16. The resistance values of the resistors 30 and 32 are the same, and the resistance values of the resistors 36 and 38 are also the same. For noise removal, a series connection body of capacitors 40 and 42 is connected in parallel to the secondary side COS coil 16, and the connection point thereof is grounded.

  Here, in the present embodiment, the resistance value of the resistor 30, the voltage of the constant voltage power supply 34 (Vc1 = 5V), and the resistors (a pair of resistors connected to the non-inverting input terminal) included in the differential amplifier circuit 20 And the voltage of the constant voltage power supply 44 (Vc2 = 2.5V) connected to the resistor included in the differential amplifier circuit 20 is set, the secondary side COS coil 16 is not short-circuited. The direct current potential (bias of the secondary side COS coil 16) with respect to the GND potential at the connection point of the series connection body of the resistors 36 and 38 is set to “4.4V”. Incidentally, the voltages of the constant voltage power supplies 34 and 44 are values of a potential difference with respect to the GND potential.

  On the other hand, a series connection body of resistors 46 and 48 is connected in parallel to the secondary side SIN coil 18, and a voltage is applied to the connection point of these resistors by a constant voltage power supply 50. In addition, a series connection body of resistors 52 and 54 is connected in parallel to the secondary side SIN coil 18. The resistance values of the resistors 46 and 48 are the same, and the resistance values of the resistors 52 and 54 are also the same. Further, for noise removal, a serial connection body of capacitors 56 and 58 is connected in parallel to the secondary side SIN coil 18, and the connection point thereof is grounded.

  Here, in the present embodiment, the voltage of the constant voltage power supply 50 (Vs1 = 2.5V) and the resistor (a pair of resistors connected to the non-inverting input terminal) included in the differential amplifier circuit 22 are connected. When the secondary side SIN coil 18 is not short-circuited by setting the voltage of the constant voltage power supply 60 (Vs2 = 2.5V), the DC current with respect to the GND potential at the connection point of the series connection body of the resistors 52 and 54 The position (bias of the secondary SIN coil 18) is lower than the DC potential “4.4V” at the connection point of the series connection body of the resistors 36 and 38 and higher than the DC potential of the primary coil 10. The value is set to “2.5V”. Incidentally, the voltages of the constant voltage power supplies 50 and 60 are values of a potential difference with respect to the GND potential.

  An RC circuit 62 is connected to a connection point of the series connection body of the resistors 36 and 38. The RC circuit 62 is a low-pass filter that outputs a low frequency component of the input voltage as a voltage across the capacitor. The output signal of the RC circuit 62 is a voltage signal corresponding to the DC potential of the secondary side COS coil 16. The output signal A of the RC circuit 62 is taken into the A / D converter 26a (AD converter) of the microcomputer 26 via an AD port (not shown) of the microcomputer 26.

  On the other hand, an RC circuit 64 is connected to a connection point of the series connection body of the resistors 52 and 54. The RC circuit 64 is a low-pass filter that outputs a low frequency component of the input voltage as a voltage across the capacitor. The output signal of the RC circuit 64 is a voltage signal corresponding to the DC potential of the secondary SIN coil 18.

  The output signal of the RC circuit 64 is input to the non-inverting input terminal of the comparator 66. A threshold voltage Vth is applied to the inverting input terminal of the comparator 66 by the power supply 68. Here, the threshold voltage Vth is lower than the output voltage “2.5 V” of the RC circuit 64 when the secondary side SIN coil 18 is not short-circuited, and the primary side coil 10 and the secondary side SIN coil. The value is set to a value “2.1 V” higher than the output voltage “0 V” of the RC circuit 64 when a short circuit occurs between the 18 circuits. The output signal B of the comparator 66 is taken into the microcomputer 26.

  Incidentally, the positive power supply terminal and the negative power supply terminal of the differential amplifier circuits 20 and 22 and the comparator 66 are respectively connected to a voltage VB (for example, 13 V) of an in-vehicle auxiliary battery (not shown) and a constant voltage power supply (not shown). Each of the negative voltages “−5V” is applied.

  Next, changes in the output signals A and B accompanying the occurrence of a short circuit will be described with reference to FIG. Here, first, the output signals A and B in the case where a short circuit does not occur (normal case) will be described, and then, when the short circuit between the secondary COS coil 16 and the secondary SIN coil 18 occurs, the primary When the short-circuit between the side coil 10 and the secondary SIN coil 18 occurs, the output signals A and B from the normal case in the order in which the short-circuit between the primary coil 10 and the secondary COS coil 16 occurs. The change will be described.

  First, a case where no short circuit occurs will be described. In this case, since the DC potential at the connection point of the series connection body of the resistors 36 and 38 is set to “4.4 V”, the microcomputer 26 sends an AD conversion value corresponding to “4.4 V” as the output signal A. Is entered. On the other hand, since the DC potential of the connection point of the series connection bodies of the resistors 52 and 54 is set to “2.5 V”, the threshold voltage Vth applied to the inverting input terminal of the comparator 66 is less than the threshold voltage Vth “2.1 V”. The voltage applied to the inverting input terminal is higher. Therefore, the output signal B of the comparator 66 having a logic “H” is input to the microcomputer 26.

  Next, a case where a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 occurs will be described. In this case, the DC potentials of the connection points of the series connection bodies of the resistors 36 and 38 and the connection points of the series connection bodies of the resistors 52 and 54 are the average of the DC potentials of these connection points when no short circuit occurs. The value is set to “3.45V”. Therefore, the AD conversion value corresponding to “3.45 V” is input to the microcomputer 26 as the output signal A. On the other hand, the logic of the output signal B of the comparator 66 is maintained at “H”.

  Next, a case where a short circuit between the primary side coil 10 and the secondary side COS coil 16 occurs will be described. In this case, the DC potential at the connection point of the series connection bodies of the resistors 36 and 38 is set to the DC potential “0 V” of the primary coil 10. Therefore, the AD conversion value corresponding to “0 V” is input to the microcomputer 26 as the output signal A. On the other hand, since the DC potential at the connection point of the series connection body of the resistors 52 and 54 does not change, the logic of the output signal B of the comparator 66 is maintained at “H”.

  Next, a case where a short circuit between the primary side coil 10 and the secondary side SIN coil 18 occurs will be described. In this case, the DC potential at the connection point of the series connection bodies of the resistors 52 and 54 is set to the DC potential “0 V” of the primary coil 10. For this reason, the voltage “0 V” applied to the non-inverting input terminal is lower than the threshold voltage Vth “2.1 V” applied to the inverting input terminal of the comparator 66, and the logic of the output signal B of the comparator 66 is Inverted from “H” to “L”. On the other hand, since the DC potential at the connection point of the series connection body of the resistors 36 and 38 does not change, the AD conversion value corresponding to “4.4 V” is input to the microcomputer 26 as the output signal A.

  According to the above-described output mode of the output signals A and B, it is possible to detect the occurrence of a short circuit and to determine the type of the short circuit that has occurred. Specifically, as shown in FIG. 2, the microcomputer 26 has no short circuit when the logic of the output signal B is “H” and the output signal A is determined to be “4.4 V”. Judging.

  On the other hand, when the logic of the output signal B is “H” and the output signal A is determined to be “3.45 V”, the secondary side COS coil 16 and the secondary side SIN coil 18 are short-circuited. Judge that it has occurred. Further, when it is determined that the logic of the output signal B is “H” and the output signal A is “0 V”, the primary side coil 10 and the secondary side COS coil 16 are short-circuited. Judging. Further, when it is determined that the logic of the output signal B is “L”, it is determined that a short circuit has occurred between the primary side coil 10 and the secondary side SIN coil 18.

  Incidentally, in the present embodiment, when it is determined that a short circuit has occurred, the microcomputer 26 executes fail-safe processing corresponding to the type of the short circuit that has occurred. Here, the fail-safe process corresponding to the type of short circuit is executed because, as shown in FIG. 3, the degree of decrease in the accuracy of detection of the electrical angle varies greatly depending on the type of short circuit. Specifically, FIGS. 3A and 3D show changes in the resolver signal when no short circuit occurs, and FIGS. 3B and 3C show the secondary side COS coil 16 and the secondary side SIN. FIG. 3E and FIG. 3F show the transition of the resolver signal when the primary side coil 10 and the secondary side COS coil 16 are short-circuited. Indicates. The resolver signal shown in FIG. 3 is measured in a state where the rotor 12a of the motor generator 12 is not rotating. In the figure, “RDCOS” indicates the output voltage of the secondary side COS coil 16 in the resolver signal, and “RDSIN” indicates the output voltage of the secondary side SIN coil 18 in the resolver signal.

  First, a case where a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 occurs will be described.

  In the example shown in FIG. 3A, the amplitude of RDCOS is larger than the amplitude of RDSIN due to the input of the excitation signal Sc to the primary coil 10. Under these circumstances, when the short circuit between the terminal C1 and the terminal S1 occurs as a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18, as shown in FIG. Are superimposed. On the other hand, even when a short circuit between the terminal C1 and the terminal S2 occurs as a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18, as shown in FIG. Superimposed. As a result, an error is superimposed on the detected value of the electrical angle of the rotor 12a.

  On the other hand, when the short circuit between the terminal C1 and the terminal R1 or the short circuit between the terminal C2 and the terminal R1 occurs as a short circuit between the primary side coil 10 and the secondary side COS coil 16, the secondary side COS coil 16 Due to the excitation circuit 14 being directly connected to one end and the excitation signal Sc being input, the RDCOS waveform shown in FIGS. 3E and 3F and the normal waveform shown in FIG. Will be greatly different. As a result, the electrical angle of the rotor 12a cannot be detected. The same applies when a short circuit between the primary side coil 10 and the secondary side SIN coil occurs.

  Considering these points, when a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 occurs, the drive of the motor generator 12 is switched to the evacuation travel mode as a fail-safe process, and the user is notified of the fact. Process.

  On the other hand, when a short circuit occurs between the primary side coil 10 and the secondary side COS coil 16 (or the secondary side SIN coil 18), the electrical angle of the rotor 12a cannot be detected. A process of prohibiting the drive of the generator 12 and notifying the user of that is performed.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) A bias is applied to each of the coils 10, 16, and 18 so that the DC potential with respect to the GND potential differs between the primary side coil 10, the secondary side COS coil 16, and the secondary side SIN coil 18. did. Then, based on the output signal A as the DC potential of the connection point of the series connection body of the resistors 36 and 38 and the output signal B of the comparator 66, the primary side coil 10 and the secondary side COS coil 16 are short-circuited. A short circuit determination process is performed to determine which one of the short circuit between the primary side coil 10 and the secondary side SIN coil 18 and the short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 occurs. It was. For this reason, the occurrence of a short circuit can be detected and the type of the short circuit that has occurred can be determined. Thereby, it is possible to easily identify the location where the short circuit occurs.

  (2) The fail safe process according to the kind of short circuit discriminated by the short circuit discrimination process was performed. As a result, it is possible to notify the user that a short circuit has occurred, and to allow the user to take appropriate action thereafter.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 4 shows a system configuration according to the present embodiment.

  As illustrated, the connection point of the series connection body of the resistors 36 and 38 is connected to the non-inverting input terminal of the first comparator 70 via the RC circuit 62. The first threshold voltage Vtha is applied to the inverting input terminal of the first comparator 70 by the power supply 72. Here, the first threshold voltage Vtha is lower than the output voltage “4.4 V” of the RC circuit 62 when the short circuit of the secondary side COS coil 16 does not occur, and the secondary side COS coils 16 and 2 The value is set to a value “4V” higher than the output voltage “3.45V” when the short circuit between the secondary side SIN coils 18 occurs. The output signal A of the first comparator 70 is taken into the microcomputer 26.

  On the other hand, the connection point of the series connection body of the resistors 52 and 54 is connected to the non-inverting input terminal of the second comparator 74 via the RC circuit 64. The second threshold voltage Vthb is applied to the inverting input terminal of the second comparator 74 by the power supply 76. Here, the second threshold voltage Vthb is lower than the output voltage “2.5 V” of the RC circuit 64 when the secondary side SIN coil 18 is not short-circuited, and the primary side coil 10 and the secondary side coil 10 The value is set to a value “2.1 V” higher than the output voltage “0 V” when the side SIN coils 18 are short-circuited. The output signal B of the second comparator 74 is taken into the microcomputer 26.

  Further, the connection point of the series connection body of the resistors 36 and 38 is connected to the non-inverting input terminal of the third comparator 78 via the RC circuit 62. A third threshold voltage Vthc is applied to the inverting input terminal of the third comparator 78 by the power supply 80. Here, the third threshold voltage Vthc is lower than the output voltage “3.45 V” of the RC circuit 62 when the secondary COS coil 16 and the secondary SIN coil 18 are short-circuited, and 1 The value is set to a value “3V” higher than the output voltage “0V” when the secondary coil 10 and the secondary COS coil 16 are short-circuited. The output signal C of the third comparator 78 is taken into the microcomputer 26.

  Next, changes in the output signals A to C accompanying the occurrence of a short circuit will be described with reference to FIG. Specifically, first, the output signals A to C in the normal case will be described, and then the primary side coil 10 and the secondary side coil 10 when the secondary side COS coil 16 and the secondary side SIN coil 18 are short-circuited. When the side SIN coils 18 are short-circuited, the change in the output signals A to C from the normal case is the order in which the primary side coil 10 and the secondary side COS coil 16 are short-circuited. explain.

  First, a case where no short circuit occurs will be described. In this case, since the DC potential at the connection point of the series connection bodies of the resistors 36 and 38 is set to “4.4 V”, the voltage applied to the non-inverting input terminal of the first comparator 70 is the first threshold value. The voltage applied to the non-inverting input terminal of the third comparator 78 is higher than the voltage Vtha and higher than the third threshold voltage Vthc. For this reason, the microcomputer 26 receives the output signals A and C of the first and third comparators 70 and 78 of logic “H”. On the other hand, since the DC potential at the connection point of the series connection body of the resistors 52 and 54 is set to “2.5 V”, the voltage applied to the non-inverting input terminal of the second comparator 74 is the second threshold voltage. It becomes higher than Vthb. Therefore, the output signal B of the second comparator 74 having a logic “H” is input to the microcomputer 26.

  Next, a case where a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 occurs will be described. In this case, since the DC potential at the connection point of the series connection body of the resistors 36 and 38 is “3.45 V”, the voltage applied to the non-inverting input terminal of the first comparator 70 is the first threshold value. It becomes lower than the voltage Vtha. For this reason, the logic of the output signal A of the first comparator 70 is inverted from “H” to “L”. The logic of the output signals B and C of the second and third comparators 74 and 78 is maintained at “H”.

  Next, a case where a short circuit between the primary side coil 10 and the secondary side COS coil 16 occurs will be described. In this case, since the DC potential at the connection point of the series connection body of the resistors 36 and 38 is set to “0 V”, the voltage applied to the non-inverting input terminal of the first comparator 70 is the first threshold voltage Vtha. And the voltage applied to the non-inverting input terminal of the third comparator 78 is lower than the third threshold voltage Vthc. Therefore, the logic of both the output signal A of the first comparator 70 and the output signal C of the third comparator 78 is inverted from “H” to “L”. Note that the logic of the output signal B of the second comparator 74 is maintained at “H”.

  Next, a case where a short circuit between the primary side coil 10 and the secondary side SIN coil 18 occurs will be described. In this case, since the DC potential at the connection point of the series connection bodies of the resistors 52 and 54 is set to “0 V”, the voltage applied to the non-inverting input terminal of the second comparator 74 is the second threshold voltage Vthb. Lower than. For this reason, the logic of the output signal B of the second comparator 74 is inverted from “H” to “L”. The logics of the output signals A and C of the first and third comparators 70 and 78 are maintained at “H”.

  Next, a method for determining the type of short circuit by the short circuit determination process according to the present embodiment will be described.

  When it is determined that all the logics of the output signals A to C of the first to third comparators 70, 74, and 78 are “H”, the microcomputer 26 determines that no short circuit has occurred.

  On the other hand, when it is determined that only the logic of the output signal A of the first comparator 70 is “L”, it is determined that a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 has occurred. When it is determined that only the logic of the output signal B of the second comparator 74 is “H”, it is determined that a short circuit between the primary side coil 10 and the secondary side COS coil 16 has occurred. Further, when it is determined that only the logic of the output signal B of the second comparator 74 is “L”, it is determined that a short circuit between the primary side coil 10 and the secondary side SIN coil 18 has occurred.

  Thus, in the present embodiment, the type of short circuit can be appropriately determined using the output signals A to C of the first to third comparators 70, 74, and 78.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, the direct current potential with respect to the GND potential of the primary side coil 10 is sandwiched between the direct current potential with respect to the GND potential of the secondary side COS coil 16 and the direct current potential with respect to the GND potential of the secondary side SIN coil 18. A configuration in which a bias is applied to each of the coils 10, 16 and 18 is employed. In the present embodiment, these coils are arranged in order from the highest DC potential so as to become the secondary side COS coil 16, the primary side coil 10, and the secondary side SIN coil 18. Such a configuration is realized by the configuration shown in FIG.

  As shown in FIG. 6, the connection point of the series connection body of the resistors 46 and 48 is grounded. One end of the primary coil 10 is connected to a constant voltage power source 82 via a terminal R2. In the present embodiment, the voltage Vr of the constant voltage power supply 82 is set to “2.5 V”. The voltage of the constant voltage power supply 82 is a potential difference value with respect to the GND potential.

  In the present embodiment, the secondary side SIN coil is set by setting the resistance value of the resistor 46, the voltage of the constant voltage power supply 60 (Vs2 = 2.5V), and the resistance value of the resistor included in the differential amplifier circuit 22. When the short circuit 18 does not occur, the bias of the secondary side SIN coil 18 is set to “0.6 V”.

  The connection point of the series connection body of the resistors 36 and 38 is connected to the non-inverting input terminal of the first comparator 84 via the RC circuit 62. The first threshold voltage Vtha is applied to the inverting input terminal of the first comparator 84 by the power supply 86. Here, the first threshold voltage Vtha is lower than the output voltage “4.4V” of the RC circuit 62 when the secondary side COS coil 16 is not short-circuited, and the primary side coil 10 and the secondary side coil 10 The value is set to “4.0 V”, which is higher than the output voltage “2.5 V” when the side COS coils 16 are short-circuited. The output signal A of the first comparator 84 is taken into the microcomputer 26.

  On the other hand, the connection point of the series connection body of the resistors 52 and 54 is connected to the non-inverting input terminal of the second comparator 88 via the RC circuit 64. The second threshold voltage Vthb is applied to the inverting input terminal of the second comparator 88 by the power supply 90. The second threshold voltage Vthb is higher than the output voltage “0.6 V” of the RC circuit 64 when the secondary side SIN coil 18 is not short-circuited, and the primary side coil 10 and the secondary side SIN. The value is set to a value “1V” lower than the output voltage “2.5V” when the short circuit between the coils 18 occurs. The output signal B of the second comparator 88 is taken into the microcomputer 26.

  Next, changes in the output signals A and B accompanying the occurrence of a short circuit will be described with reference to FIG.

  First, a case where no short circuit occurs will be described. In this case, since the DC potential at the connection point of the series connection bodies of the resistors 36 and 38 is set to “4.4 V”, the voltage applied to the non-inverting input terminal of the first comparator 84 is the first threshold value. It becomes higher than the voltage Vtha. For this reason, the logic of the output signal A of the first comparator 84 is set to “H”. On the other hand, since the DC potential at the connection point of the series connection bodies of the resistors 52 and 54 is set to “0.6 V”, the voltage applied to the non-inverting input terminal of the second comparator 88 is the second threshold voltage. It becomes lower than Vthb. For this reason, the logic of the output signal B of the second comparator 88 is set to “L”.

  Next, a case where a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 occurs will be described. In this case, the DC potential at the connection point of the series connection body of the resistors 36 and 38 and the connection point of the series connection body of the resistors 52 and 54 is set to “2.5 V”. For this reason, the voltage applied to the non-inverting input terminal of the first comparator 84 becomes lower than the first threshold voltage Vtha, and the logic of the output signal A of the first comparator 84 changes from “H” to “L”. Inverted. Further, the voltage applied to the non-inverting input terminal of the second comparator 88 becomes higher than the second threshold voltage Vthb, and the logic of the output signal A of the second comparator 88 is inverted from “L” to “H”. Is done.

  Next, a case where a short circuit between the primary side coil 10 and the secondary side COS coil 16 occurs will be described. In this case, since the DC potential at the connection point of the series connection bodies of the resistors 36 and 38 is set to “2.5 V”, the voltage applied to the non-inverting input terminal of the first comparator 84 is the first threshold value. It becomes lower than the voltage Vtha. For this reason, the logic of the output signal A of the first comparator 84 is inverted from “H” to “L”. The logic of the output signal B of the second comparator 88 is maintained at “L”.

  Next, a case where a short circuit between the primary side coil 10 and the secondary side SIN coil 18 occurs will be described. In this case, since the DC potential at the connection point of the series connection bodies of the resistors 52 and 54 is set to “2.5 V”, the voltage applied to the non-inverting input terminal of the second comparator 88 is the second threshold value. It becomes higher than the voltage Vthb. For this reason, the logic of the output signal B of the second comparator 88 is inverted from “L” to “H”. Note that the logic of the output signal A of the first comparator 84 is maintained at “H”.

  Next, a method for determining the type of short circuit by the short circuit determination process according to the present embodiment will be described.

  When the logic of the output signal A of the first comparator 84 is “H” and the logic of the output signal B of the second comparator 88 is “L”, the microcomputer 26 causes a short circuit. Judge that not.

  On the other hand, when the logic of the output signal A of the first comparator 84 is “L” and the logic of the output signal B of the second comparator 88 is determined to be “H”, the secondary side COS coil It is determined that the short circuit between the 16 and secondary side SIN coils 18 has occurred. When it is determined that the logic of both the output signal A of the first comparator 84 and the output signal B of the second comparator 88 is “L”, the primary side coil 10 and the secondary side COS coil 16 are connected to each other. It is determined that a short circuit has occurred. Further, when it is determined that the logic of both the output signal A of the first comparator 84 and the output signal B of the second comparator 88 is “H”, the primary side coil 10 and the secondary side SIN coil 18 are connected to each other. It is determined that a short circuit has occurred.

  As described above, in this embodiment, a configuration is employed in which the logic of the output signal of the comparator corresponding to the one in which the short circuit occurs in the secondary side COS coil 16 and the secondary side SIN coil 18 is inverted. For this reason, an increase in the number of components required for determining the type of short circuit can be avoided, for example, the number of comparators can be reduced as compared with the method for determining the type of short circuit in the second embodiment.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings with a focus on differences from the third embodiment.

  In this embodiment, the setting of the absolute value of the DC potential of the secondary side COS coil 16, the primary side coil 10, and the secondary side SIN coil 18 is changed.

  Specifically, as shown in FIG. 8, one end of the primary coil 10 is grounded via a terminal R2.

  A voltage is applied by a constant voltage power source 92 to a connection point of the series connection body of the resistors 46 and 48. In the present embodiment, the resistors 52 and 54 are connected in series by setting the voltage “Vs1” of the constant voltage power supply 92, the resistance value of the resistor included in the differential amplifier circuit 22, and the voltage “Vs2” of the constant voltage power supply 60. The DC potential of the body connection point is set to “−2.5V”.

  Incidentally, in the present embodiment, the first threshold voltage Vtha of the first comparator 84 is lower than the output voltage “4.4 V” of the RC circuit 62 when the secondary side COS coil 16 is not short-circuited. In addition, the value is set to a value “4V” higher than the output voltage “0V” when the primary side coil 10 and the secondary side COS coil 16 are short-circuited. The second threshold voltage Vthb of the second comparator 88 is higher than the output voltage “−2.5 V” of the RC circuit 64 when the secondary side SIN coil 18 is not short-circuited, and The value is set to a value “−2.1 V” lower than the output voltage “0 V” when the side coil 10 and the secondary SIN coil 18 are short-circuited.

  Furthermore, FIG. 9 shows a method of determining the type of short circuit based on the changes in the output signals A and B accompanying the occurrence of a short circuit and the output signals A and B according to the present embodiment. This method is in accordance with the determination method described with reference to FIG. 7 of the third embodiment.

  As described above, in this embodiment, the setting of the absolute value of the DC potential of the secondary side COS coil 16, the primary side coil 10, and the secondary side SIN coil 18 is changed. Even with such a configuration, it is possible to appropriately determine the type of short circuit.

(Fifth embodiment)
Hereinafter, a fifth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

  In the present embodiment, as the short-circuit discrimination processing, a short circuit (ground fault) between one of the secondary COS coil 16 and the secondary SIN coil 18 and the ground, or one of these coils 16 and 18 and the positive electrode of the on-vehicle battery. A process of determining whether or not a short circuit (power fault) with the side has occurred is further performed. In order to perform this processing, in the present embodiment, the direct current potential with respect to the GND potential is not set to 0 in each of the primary side coil 10, the secondary side COS coil 16, and the secondary side SIN coil 18. , 16 and 18 are configured so that a bias is applied to each of the coils 10, 16 and 18 so that the DC potential with respect to the GND potential does not become the potential on the positive side of the battery.

  Specifically, as shown in FIG. 10, one end of the primary coil 10 is connected to a constant voltage power supply 94 via a terminal R2. In the present embodiment, the voltage Vr of the constant voltage power supply 94 is set to “1.5 V”. Here, the voltage of the constant voltage power supply 94 is a value of a potential difference with respect to the GND potential.

  Further, the DC potential with respect to the GND potential at the connection point of the series connection body of the resistors 36 and 38 and the DC potential with respect to the GND potential at the connection point of the series connection body of the resistors 52 and 54 are set as follows. First, the DC potential at the connection point of the series connection body of the resistors 36 and 38 will be described. The resistance value of the resistor 30, the voltage of the constant voltage power supply 34, the resistance value of the resistor included in the differential amplifier circuit 20, and the constant value. The DC potential with respect to the GND potential at the connection point is set to “4.5 V” by setting the voltage of the voltage power supply 44. Next, the DC potential at the connection point of the series connection body of the resistors 52 and 54 will be described. The voltage of the constant voltage power supply 50 (Vs1 = 5 V), the resistance value of the resistor included in the differential amplifier circuit 22, By setting with the voltage of the voltage power supply 60, the DC potential with respect to the GND potential at the connection point is set to “3V”.

  The output voltage at the connection point of the series connection body of the resistors 52 and 54 is taken in as an output signal B to the A / D conversion unit 26a of the microcomputer 26 via the RC circuit 64.

  Next, changes in the output signals A and B accompanying the occurrence of a ground fault or a power fault will be described with reference to FIG. FIG. 11 also shows changes in the output signals A and B when a short circuit occurs between the coils. However, changes in the output signals A and B when the coils are short-circuited are in accordance with those described with reference to FIG. 2 in the first embodiment. For this reason, in this embodiment, description about the change of the output signals A and B accompanying generation | occurrence | production of the short circuit between coils is abbreviate | omitted.

  First, a case where a ground fault occurs will be described.

  When the ground fault of the secondary side COS coil 16 occurs, the direct current potential at the connection point of the series connection bodies of the resistors 36 and 38 is set to the GND potential “0 V”. An AD conversion value corresponding to “0V” is input. On the other hand, when the ground fault of the secondary side SIN coil 18 occurs, the DC potential at the connection point of the series connection body of the resistors 52 and 54 is set to the GND potential “0V”, similarly to the ground fault of the secondary side COS coil 16. Therefore, the AD conversion value corresponding to “0 V” is input to the microcomputer 26 as the output signal B.

  Incidentally, when a ground fault occurs at the terminal R <b> 1 as a ground fault of the primary side coil 10, the primary side coil 10 cannot be excited by the excitation circuit 14.

  Next, a case where a power fault occurs will be described.

  When the secondary side COS coil 16 has a power supply fault, the DC potential at the connection point of the series connection body of the resistors 36 and 38 is set to the positive side potential VB (13 V) of the battery. Therefore, the microcomputer 26 receives an AD conversion value corresponding to the maximum value “5 V” of the voltage that can be input to the A / D conversion unit 26 a as the output signal A. On the other hand, when the secondary side SIN coil 18 has a power fault, the DC potential at the connection point of the series connection bodies of the resistors 52 and 54 is the positive side potential VB of the battery, similarly to the secondary side COS coil 16. It is said. Therefore, an AD conversion value corresponding to the maximum voltage value “5 V” that can be input to the A / D conversion unit 26 a is input to the microcomputer 26 as the output signal B.

  Next, a method for discriminating types of short circuit, ground fault, and power fault by the short circuit discrimination process according to the present embodiment will be described.

  First, a method for determining the type of short circuit will be described.

  When it is determined that the output signal A is “4.5V” and the output signal B is “3V”, the microcomputer 26 determines that a short circuit has not occurred.

  On the other hand, when it is determined that both the output signals A and B are “3.75 V”, it is determined that a short circuit between the secondary side COS coil 16 and the secondary side SIN coil 18 has occurred. Further, when it is determined that the output signal A is “1.5 V” and the output signal B is “3 V”, the primary side coil 10 and the secondary side COS coil 16 are short-circuited. Judging. Furthermore, when it is determined that the output signal A is “4.5 V” and the output signal B is “1.5 V”, a short circuit between the primary side coil 10 and the secondary side SIN coil 18 occurs. Judge that it is.

  Next, a method for determining the type of ground fault will be described.

  When it is determined that the output signal A is “0V” and the output signal B is “3V”, the microcomputer 26 determines that a ground fault has occurred in the secondary COS coil 16. On the other hand, if it is determined that the output signal A is “4.5 V” and the output signal B is “0 V”, it is determined that a ground fault has occurred in the secondary SIN coil 18.

  When a ground fault of the terminal R2 occurs as a ground fault of the primary side coil 10, a short circuit determination is performed in order to avoid a situation where a short circuit current flows from the constant voltage power source 94 to the ground and the reliability of the power source decreases. After the process is completed, it is desirable to perform a process for stopping the power supply by the constant voltage power source 92.

  Next, a method for determining the type of skylight will be described.

  When the microcomputer 26 determines that the output signal A is “5V” and the output signal B is “3V”, the microcomputer 26 determines that a power supply fault has occurred in the secondary COS coil 16, and the output signal When it is determined that A is “4.5V” and the output signal B is “5V”, it is determined that a power fault of the secondary side SIN coil 18 has occurred.

  In addition, when the power supply of the primary side coil 10 arises, an excessive electric current will flow into the excitation circuit 14, and there exists a possibility that the reliability of the excitation circuit 14 may fall. For this reason, in this embodiment, when it is determined that a power fault of the primary coil 10 is generated by a determination method described later, a process of cutting off the power supply between the excitation circuit 14 and the outside is performed. Thereby, excitation of the primary side coil 10 by the excitation circuit 14 is stopped.

  Further, the ground fault and the power fault of the primary coil 10 cannot be detected by the above-described discrimination method using the short-circuit discrimination process. For this reason, what is necessary is just to detect the ground fault and the power fault of the primary side coil 10 using the method described in the patent 3588499, for example. Briefly describing this method, first, an addition value of a value obtained by squaring the output voltage of the secondary side COS coil 16 and a value obtained by squaring the output voltage of the secondary side SIN coil 18 is calculated each time. Then, the maximum value of the addition value calculated each time is calculated, and whether or not a ground fault or a power fault has occurred in the primary coil 10 based on a comparison between the calculated maximum value and a preset specified value. Judging. In this method, when a ground fault or a power fault occurs, the excitation signal Sc output from the excitation circuit 14 deviates from the normal signal so that the outputs of the secondary COS coil 16 and the secondary SIN coil 18 are output. This is based on the voltage deviating from the normal voltage.

  As described above, in the present embodiment, the direct current potential with respect to the GND potential does not become 0 in each of the primary side coil 10, the secondary side COS coil 16, and the secondary side SIN coil 18. , 18 is configured such that a bias is applied to each of the coils 10, 16, 18 so that the DC potential with respect to the GND potential does not become the positive electrode side potential VB of the battery. According to such a configuration, it is possible to detect that a ground fault or a power fault has occurred in either the secondary side COS coil 16 or the secondary side SIN coil 18.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In the first to fourth embodiments, the non-inverting input terminal of the comparator and the connection point of the series connection body of the pair of resistors are connected, but not limited to this, the inverting input terminal of the comparator and the connection point May be connected. In this case, for example, in the first embodiment, the logic of the output signal of the comparator 66 is inverted from the logic shown in FIG.

  The method for setting the first threshold voltage Vtha and the second threshold voltage Vthb is not limited to that exemplified in the third embodiment. For example, the first threshold voltage Vtha is lower than the output voltage “4.4 V” of the RC circuit 62 when the secondary side COS coil 16 is not short-circuited, and the primary side coil 10 and the secondary side A value other than “4.0 V” may be set as long as the output voltage is higher than “2.5 V” when the COS coils 16 are short-circuited.

  Further, for example, the second threshold voltage Vthb is higher than the output voltage “0.6 V” of the RC circuit 64 when the secondary side SIN coil 18 is not short-circuited, and the primary side coils 10 and 2. A value other than “1V” may be set as long as it is a value lower than the output voltage “2.5 V” when the short circuit between the secondary side SIN coils 18 occurs.

  In the first embodiment, the connection point of the series connection body of the resistors 36 and 38 is connected to the non-inverting input terminal of the comparator 66, and the connection point of the series connection body of the resistors 52 and 54 is connected to the microcomputer 26. It is good also as a structure input into the A / D conversion part 26a. In this case, the inverting input terminal of the comparator 66 is lower than the output voltage “4.4 V” of the RC circuit 62 when the short circuit of the secondary side COS coil 16 does not occur, and the secondary side COS coil 16 and A voltage higher than the output voltage “3.45 V” when a short circuit between the secondary side SIN coils 18 occurs is applied by a power source.

  With this configuration, the type of short circuit can be determined based on the AD conversion value of the output voltage of the RC circuit 62 and the output signal of the comparator 66.

  In the second embodiment, the non-inverting input terminal of the third comparator 78 is replaced with the connection point of the series connection body of the resistors 36 and 38, instead of the connection point of the series connection body of the resistors 36 and 38. You may connect. In this case, when the secondary side SIN coil 18 is not short-circuited, or when the primary side coil 10 is short-circuited with any one of the secondary-side COS coil 16 and the secondary-side SIN coil 18, the third When the logic of the output signal of the comparator 78 is “L” and the secondary side COS coil 16 and the secondary side SIN coil 18 are short-circuited, the logic of the output signal is “H”. Even in such a configuration, it is possible to determine the type of short circuit based on the output signals A to C of the first to third comparators 70, 74, and 78.

  -The resolver is not limited to the one-phase excitation two-phase output type. For example, a two-phase excitation two-phase output type may be used. Specifically, this resolver inputs AC voltage signals having the same amplitude and 90 degrees of phase to each of a pair of primary coils, so that the phases of each of the pair of secondary coils are mutually different. A pair of output signals differing by 90 degrees and corresponding to the rotation angle of the rotor 12a are output. In this case, a bias voltage may be applied to each of the coils so that the DC potential with respect to the GND potential differs between the primary side coil and the secondary side coil. Here, the direct current potential with respect to the GND potential may be the same between the pair of primary coils. Then, based on each of the DC potentials with respect to the respective GND potentials of the secondary coils, a short circuit between one of the pair of primary coils and one of the pair of secondary coils, and the pair of secondary coils It is possible to determine which of the short circuits has occurred.

  The number of secondary coils provided in the resolver is not limited to two, and may be three or more. Even in this case, if the DC potential with respect to the reference potential (GND potential) is made different between the primary coil and the secondary coil, the primary side is based on the DC potential of the secondary coil. It is possible to determine which one of the short circuit between the coil and the secondary coil and the short circuit between any pair of the secondary coils occurs.

  -As a signal detection apparatus, it is not restricted to what is applied to a resolver.

  The vehicle to which the present invention is applied is not limited to an electric vehicle, and may be another vehicle (for example, a hybrid vehicle) including a motor generator as an in-vehicle main unit.

  DESCRIPTION OF SYMBOLS 10 ... Primary side coil, 14 ... Excitation circuit, 16 ... Secondary side COS coil, 18 ... Secondary side SIN coil, 20, 22 ... Differential amplifier circuit, 24 ... R / D conversion part, 26 ... Microcomputer, 26a ... A / D converter, 66 ... comparator.

Claims (5)

It is applied to a signal detection device in which each of a pair of secondary coils magnetically coupled to a primary coil to which an alternating voltage signal is input is a voltage detection target,
In so that the DC potential with respect to the reference potential of the primary coil is sandwiched between the DC potential with respect to the reference potential of the pair of the secondary coil, the bias to each of said primary coil and said secondary coil A bias applying means for applying
Of the pair of secondary side coils, the higher DC potential with respect to the reference potential is the high potential side coil, the remainder is the low potential side coil,
When the high potential side coil is short-circuited between the primary side coil and the high potential side coil that is lower than the DC potential with respect to the reference potential of the high potential side coil when the high potential side coil is not short-circuited A value higher than the DC potential with respect to the reference potential of the high potential side coil is set as the first threshold voltage,
When the short-circuit between the primary side coil and the low-potential side coil is higher than the DC potential with respect to the reference potential of the low-potential side coil when the low-potential side coil is not short-circuited A value lower than the DC potential with respect to the reference potential of the low potential side coil is set as the second threshold voltage,
Based on the magnitude comparison between the DC potential of the high potential side coil with respect to the reference potential and the first threshold voltage, and the magnitude comparison between the DC potential with respect to the reference potential of the low potential side coil and the second threshold voltage. , a short circuit between the primary coil and the secondary coil, characterized in that it comprises the short circuit determination hand stage to perform the process of determining whether one has occurred among short-circuit between the secondary coil Short-circuit detection device. Based on the comparison between the first threshold voltage and the DC potential with respect to the reference potential before Symbol high potential side coil, a first comparator for outputting one of the signal of logic "H" and logic "L",
Based on the comparison between the DC voltage and the second threshold voltage to the reference potential of the low potential side coil, further a second comparator for outputting one of the signal of logic "H" and logic "L" Prepared,
Before Symbol short circuit determination means, based on said first comparator and both an output signal of the second comparator, the short-circuit detecting device according to claim 1, wherein the performing processing for the discrimination. It is applied to a signal detection device in which each of a pair of secondary coils magnetically coupled to a primary coil to which an alternating voltage signal is input is a voltage detection target,
Bias application means for applying a bias to each of the primary side coil and the secondary side coil so that a direct current potential with respect to a reference potential is different between the primary side coil and the secondary side coil;
Of the pair of secondary side coils, the higher DC potential with respect to the reference potential is the high potential side coil, the remainder is the low potential side coil,
The direct current potential with respect to the reference potential of the primary side coil is set lower than the direct current potential with respect to the reference potential of the low potential side coil,
When the short circuit between the high potential coil and the low potential coil occurs when the high potential coil is lower than the DC potential with respect to the reference potential when the high potential coil is not short-circuited. A value higher than the DC potential with respect to the reference potential of the high potential side coil is set as the first threshold voltage,
When a short circuit between the primary coil and the low potential coil occurs when the low potential coil is lower than the DC potential with respect to the reference potential when the low potential coil is not short circuited A value higher than the DC potential with respect to the reference potential of the low potential side coil is set as the second threshold voltage,
When the short circuit between the high potential side coil and the low potential side coil occurs, the high potential side coil is lower than the DC potential with respect to the reference potential, and the primary side coil and the high potential side coil A value higher than the DC potential with respect to the reference potential of the high potential side coil when a short circuit occurs is set as the third threshold voltage,
Comparison between the DC potential of the high potential side coil with respect to the reference potential and the first threshold voltage, comparison of the size of the DC potential with respect to the reference potential of the low potential side coil and the second threshold voltage, and Based on a comparison between the DC potential of the high potential side coil with respect to the reference potential and the third threshold voltage, a short circuit between the primary side coil and the secondary side coil, and a short circuit between the secondary side coils, A short-circuit detecting device comprising short-circuit determining means for performing processing for determining which of the two occurs. The reference potential is a ground potential of the signal detection device,
The bias applying means applies a bias to each of the primary side coil and the secondary side coil so that a DC potential with respect to the ground potential does not become 0 in each of the primary side coil and the secondary side coil. And
2. The short circuit determination unit further performs a process of determining whether or not a ground fault has occurred in the secondary coil based on a DC potential with respect to the ground potential of the secondary coil. The short circuit detection apparatus of any one of -3 . The bias applying means includes the primary coil and the secondary coil so that a direct current potential of the primary coil and the secondary coil with respect to the reference potential does not become a positive potential of a direct current power source of the signal detection device. Apply a bias to each secondary coil,
The short-circuit determining means further performs a process of determining whether or not a short-circuit has occurred between the secondary coil and the positive electrode side of the DC power source based on a DC potential with respect to the reference potential of the secondary coil. short-circuit detecting device according to any one of claims 1 to 4, characterized in.

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