JP5169949B2 - Voltage detector - Google Patents

Description

  The present invention relates to a voltage detection means for outputting an analog signal corresponding to the voltage of a battery mounted on a vehicle, a low-pass filter for inputting an analog signal output from the voltage detection means, and an output of the low-pass filter as a digital signal. The present invention relates to a voltage detection device including analog-digital conversion means for conversion.

  For example, in a hybrid vehicle, an electric vehicle, a fuel cell vehicle, and the like, it is common to use an assembled battery as a series connection body of a plurality of battery cells while being insulated from the vehicle body. For these battery cells, various monitoring devices for monitoring the state have been proposed and partially put into practical use. That is, for example, as can be seen in Patent Document 1 below, a device including a multiplexer that selectively connects a plurality of battery cells to a flying capacitor and a switching element that connects the flying capacitor to a voltage detection circuit has been proposed. Thus, after charging the flying capacitor by electrically connecting the battery cell and the flying capacitor, the voltage between the both ends of the flying capacitor is detected by the voltage detection circuit in a state where the electrical connection between the battery cell and the flying capacitor is cut off. By detecting this, the voltage of the battery cell can be detected while insulating the assembled battery from the vehicle.

Japanese Patent No. 3672183

  However, since various noise sources exist in the vehicle, noise may be superimposed on the output signal of the voltage detection circuit. For this reason, it is desired that the output signal of the voltage detection circuit is once filtered by a low-pass filter prior to capturing the output signal. However, if the cutoff frequency of the low-pass filter is set so as to cope with the expected lowest frequency noise, there is a problem that the time required for voltage detection is unnecessarily extended when the influence of the low frequency noise is small. Arise.

  In addition, when an abnormality occurs in the low-pass filter, there is a possibility that it may be erroneously recognized as a detected value of the correct voltage even though the reliability of the signal output from the low-pass filter is reduced.

  It is not limited to the one provided with the above-mentioned flying capacitor, but when detecting the voltage of a battery mounted on a vehicle, such a situation that it is difficult to properly detect the voltage while removing the influence of noise is generally common. It has become.

  The present invention has been made to solve the above-described problems, and its purpose is to more appropriately detect the voltage while suitably removing the influence of noise when detecting the voltage of the battery mounted on the vehicle. An object of the present invention is to provide a voltage detection device that can be used.

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

According to a first aspect of the present invention, there is provided voltage detection means for outputting an analog signal corresponding to a voltage of a battery mounted on a vehicle, a low-pass filter for inputting an analog signal output from the voltage detection means, and digitally outputting an output of the low-pass filter. In the voltage detection apparatus comprising analog-digital conversion means for converting into a signal, the low-pass filter comprises a plurality of filters connected in parallel between the voltage detection means and the analog-digital conversion means. The transmission characteristics of frequency signals are different from each other.

  In the above invention, since a plurality of filters having different frequency signal transmission characteristics are provided, it is possible to use an appropriate filter according to the requirements of the ambient noise level and voltage detection accuracy. Also, by providing a plurality of filters, it is possible to diagnose whether there is an abnormality in the filter based on a comparison between the output values of the filters.

A second invention is characterized in that, in the first invention, an electrical path connecting the plurality of filters and the output terminal of the voltage detecting means is a path having a fixed impedance.

  In the above invention, the electrical path is a fixed impedance path, so that an analog signal can be input to the filter easily and quickly compared to the case where the impedance is variable by providing a switch or the like here. This makes it possible to quickly converge the output value of the filter. Moreover, compared with the case where a switch etc. are provided in the said electrical pathway, the reduction of a number of parts and simplification of a structure can also be implement | achieved.

According to a third invention, in the first or second invention, the battery constitutes an in-vehicle high voltage system, a capacitor, a high voltage side opening / closing means for opening / closing the battery and the capacitor, the capacitor, Low voltage side opening / closing means for opening / closing between the voltage detection means.

  In the above invention, since the charging voltage of the capacitor becomes the voltage of the battery, the analog signal output from the voltage detecting means, which is a signal corresponding to the charging voltage of the capacitor, becomes a signal corresponding to the voltage of the battery. On the other hand, even when the high-voltage side opening / closing means and the low-voltage side opening / closing means are in the open state, noise can propagate from the assembled battery side to the voltage detection means side via the stray capacitance, but depending on the setting of the low-pass filter, This noise can be removed.

According to a fourth invention, in the third invention, means for performing a zero point detection process for detecting an output voltage of the voltage detection means in a state where both the high voltage side opening / closing means and the low voltage side opening / closing means are opened. Further, the analog-to-digital conversion means converts an analog signal output from a filter having a lower transmission frequency in the zero point detection process than in the battery voltage detection into a digital signal.

  The influence of noise tends to be particularly noticeable during the zero point detection process. In the above invention, in view of this point, the noise removal function of the filter is strengthened when the zero point is detected. Further, at the time of normal voltage detection, it is possible to reduce the time required until the output value of the filter converges by weakening the noise removal function of the filter, and thus the time for maintaining the low-voltage side opening / closing means in the closed state. And voltage detection time can be shortened. Further, when the low-voltage side opening / closing means is constituted by a photo-insulating element such as a photo MOS relay, the power consumption required to make the low-voltage side opening / closing means large is large. By shortening, power consumption can be reduced.

According to a fifth invention, in any one of the first to fourth inventions, the battery exchanges electric power with a rotating machine as an in-vehicle main machine via a power conversion circuit. The conversion means is characterized in that the conversion target at the time of detecting the voltage of the battery is an analog signal output from a filter having a higher transmission frequency when the power conversion circuit is stopped than when it is driven.

This is a significant noise source when the power conversion circuit is driven. In the above invention, in view of this point, when the power conversion circuit is stopped, the convergence time of the output value of the filter is shortened by weakening the noise removal effect. Thereby, voltage detection time can be shortened. In addition, when this invention is provided with 3rd invention specific matter, the period which makes a low voltage | pressure side opening / closing means a closed state can be shortened. Here, when the low-voltage side opening / closing means is constituted by a photo-insulating element such as a photo MOS relay, the power consumption required for making this closed is large. By shortening, power consumption can be remarkably reduced.

According to a sixth invention, in any one of the first to fifth inventions, based on a comparison of output values of the plurality of filters when the same voltage is detected by the voltage detecting means, an abnormality of the filters is detected. An abnormality diagnosis means for diagnosing the presence or absence is further provided.

  In the above invention, in view of providing a plurality of filters, it is possible to diagnose the presence or absence of a filter abnormality by comparing these output values.

According to a seventh invention, in any one of the first to sixth inventions, the filter is configured by an RC circuit.

  In the above invention, the low-pass filter can be configured with a simple configuration.

1 is a system configuration diagram according to a first embodiment. FIG. The time chart which shows the voltage detection process aspect concerning the embodiment. The figure which shows the filter characteristic concerning the embodiment. 6 is a flowchart showing a procedure of filter selection processing according to the embodiment; The flowchart which shows the procedure of the abnormality diagnosis process of the filter concerning 2nd Embodiment. The time chart which illustrates the abnormality diagnosis aspect concerning the embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a voltage detection apparatus according to the present invention is applied to a hybrid vehicle will be described with reference to the drawings.

  FIG. 1 shows the system configuration of this embodiment. The illustrated assembled battery 10 constitutes a vehicle-mounted high-voltage battery, and supplies power to a rotating machine as a main machine, charges electric energy supplied from the vehicle-mounted rotating machine, and further includes a step-down converter. The power is supplied to the vehicle-mounted low-voltage battery via the power supply (in the figure, the inverter 14 connected to the rotating machine is described). The assembled battery 10 is a serially connected body of battery cells 12 made of a lithium ion secondary battery. Specifically, the assembled battery 10 is grouped into a predetermined number of adjacent battery cells 12 to form a block Bi (i = 0 to 6).

  A wiring Li is connected to the negative terminal of each block Bi constituting the assembled battery 10, and a wiring L (i + 1) is connected to the positive terminal of each block Bi. Each wiring Lj (j = 0 to 7) is connected to the multiplexer MPX.

  The multiplexer MPX selectively connects the pair of wirings Li and L (i + 1) to the flying capacitor 16. Specifically, the multiplexer MPX connects the pair of wirings Li and L (i + 1) to the flying capacitor 16 in such a manner that the charging polarities when the voltages of adjacent blocks are applied to the flying capacitor 16 are opposite to each other. The multiplexer MPX includes a high-voltage side switching element SWj corresponding to each wiring Lj, and the high-voltage side switching elements SW7, SW5, SW3, SW1 and the high-voltage side switching elements SW6, SW4, SW2, SW0 are flying. The capacitors 16 are connected to different electrodes. Note that the high-voltage side switching elements SW0 to SW7 are configured by an insulating element such as a photo MOS relay, for example.

  The flying capacitor 16 can be connected to the differential amplifier circuit 20 via low-voltage side switching elements Sa and Sb constituted by photo MOS relays. The differential amplifier circuit 20 includes an operational amplifier 21. That is, the output terminal and the inverting input terminal of the operational amplifier 21 are connected by the resistor 22. The inverting input terminal is connected to the low voltage side switching element Sa via the resistor 23, and the non-inverting input terminal is connected to the low voltage side switching element Sb via the resistor 24. A power supply 26 is connected to the non-inverting input terminal of the operational amplifier 21 through a resistor 25. This is for fixing the polarity of the output voltage of the differential amplifier circuit 20 regardless of the charging voltage of the flying capacitor 16.

  The flying capacitor 16 is electrically connected to the differential amplifier circuit 20 via the low-voltage side switching elements Sa and Sb, so that the voltage of the flying capacitor 16 is detected by the differential amplifier circuit 20. The analog signal output from the differential amplifier circuit 20 is taken into a microcomputer (microcomputer 40) through low-pass filters (filters 30a, 30b, 30c). The microcomputer 40 includes an analog-digital converter (A / D converter 42), and thereby converts the output voltage of the differential amplifier circuit 20 (the output voltage of the filters 30a, 30b, 30c) into digital data. The central processing unit (CPU 44) performs various digital processes such as calculating the remaining capacity (SOC) of the block based on the digital data output from the A / D converter 42.

  Here, the block voltage detection process will be described in more detail. FIG. 2 shows a voltage detection processing mode according to the present embodiment. Specifically, FIG. 2A shows the transition of the operation state of the multiplexer MPX, FIG. 2B shows the transition of the operation state of the low-voltage side switching elements Sa and Sb, and FIG. The transition of the output voltage of the dynamic amplifier circuit 20 is shown.

  As illustrated, after the multiplexer MPX (a pair of adjacent high-voltage side switching elements Si, S (i + 1)) is turned on for a predetermined time T1, the flying capacitor 16 is charged to the block voltage, The low voltage side switching elements Sa and Sb are turned on for a predetermined time T2. As a result, the output voltage of the differential amplifier circuit 20 changes to a voltage corresponding to the voltage of the flying capacitor 16. Thereafter, both the high-voltage side switching elements S0 to S7 and the low-voltage side switching elements Sa and Sb of the multiplexer MPX are turned off for a predetermined time T3. This is for performing processing (zero point detection processing) for detecting the output voltage of the differential amplifier circuit 20 when no voltage is applied to the pair of input terminals of the differential amplifier circuit 20. Here, in the zero point detection processing, not only the low voltage side switching elements Sa and Sb but also the high voltage side switching elements S0 to S7 are turned off regardless of whether the low voltage side switching elements Sa and Sb are abnormal or not. This is a setting for reliably performing the outgoing processing.

  By periodically performing the above three steps, the block voltage indirect detection process through the voltage detection of the flying capacitor 16 and the zero point detection process can be performed alternately.

  By the way, when noise is mixed in the differential amplifier circuit 20 during the voltage detection process or the zero point detection process, the reliability of these processes decreases. In particular, when the inverter 14 is driven, high-frequency noise corresponding to the switching frequency when operating the switching element of the inverter 14 may be mixed into the differential amplifier circuit 20. The influence of noise due to the drive of the inverter 14 becomes particularly significant during the zero point detection process. This is because the zero point detection process is performed in a state where both the high-voltage side switching elements S0 to S7 and the low-voltage side switching elements Sa and Sb constituting the multiplexer MPX are turned off. That is, in this case, high-frequency noise from the inverter 14 side propagates to the differential amplifier circuit 20 via the stray capacitances of the high-voltage side switching elements S0 to S7 and the low-voltage side switching elements Sa and Sb. This can be more prominent than when the low-voltage side switching elements Sa and Sb are turned on.

  For this reason, it is desirable to enhance the function of removing noise from the output signal of the differential amplifier circuit 20 during the zero point detection process. However, as the function of removing noise is strengthened, the time required until an appropriate voltage corresponding to the voltage of the flying capacitor 16 is applied to the A / D converter 42 is extended.

  Therefore, in the present embodiment, the noise removal function (frequency signal transmission performance) of the filters 30a, 30b, and 30c described above is made different. Specifically, these filters 30a, 30b, and 30c are all configured by RC circuits, and the respective cutoff frequencies are made different. This is done by adjusting the resistance value of the resistor and the capacitance of the capacitor in an RC circuit that is a series connection of the resistor and the capacitor, and the connection point of the resistor and the capacitor is the output terminal. Can do.

  FIG. 3 shows the characteristics of the filters 30a, 30b, and 30c. In FIG. 3, the filters 30a, 30b, and 30c are A, B, and C, respectively. As illustrated, there is a relationship of “fa <fb <fc” between the cut-off frequencies fa, fb, and fc of the filters 30a, 30b, and 30c. For this reason, the filter 30a can remove even the lowest frequency signal. For this reason, by setting the cut-off frequency fa to a switching frequency (several hundred Hz to several kHz) or less (several hundred Hz) of the inverter 14, noise caused by driving the inverter 14 is surely removed. Furthermore, in view of the fact that the delay time becomes longer as the cut-off frequency is lower, the degree of priority between the request for noise removal and the request for shortening the detection time when detecting (digitizing) the output voltage of the differential amplifier circuit 20 Switch the filter to be used according to.

  FIG. 4 shows a digital processing procedure of the output voltage of the differential amplifier circuit 20 according to the present embodiment. This process is repeatedly executed by the microcomputer 40 at a predetermined cycle, for example.

  In this series of processing, first, in step S10, it is determined whether or not it is timing for conversion to digital data by the A / D converter 42. If it is determined that it is the conversion timing, it is determined in step S12 whether or not it is during the zero point detection process. This process is for determining whether or not the priority for the noise removal request is particularly high. If it is determined that the zero point detection process is being performed, it is determined that the priority for the noise removal request is particularly large, and the output value of the filter 30a is converted into digital data by the A / D converter 42 in step S14. To do.

  On the other hand, if it is determined in step S12 that it is not during the zero point detection process, it is determined in step S16 whether or not the inverter 14 is stopped. This process is for determining whether or not a significant noise does not occur. If it is determined that the inverter 14 is stopped, it is determined that no significant noise is generated, so that the priority of noise removal is low, and the process proceeds to step S18. In step S18, the output value of the filter 30c is converted into digital data by the A / D converter. On the other hand, when it is determined that the inverter 14 is not stopped, the process proceeds to step S20, and the output value of the filter 30b is converted into digital data by the A / D converter 42.

  In addition, when the process of step S14, S18, S20 is completed, this series of processes is once complete | finished.

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

  (1) Between the voltage detection means (differential amplifier circuit 20) and the analog-digital conversion means (A / D converter 42), a plurality of filters 30a, 30b. 30c was connected in parallel. This makes it possible to use an appropriate filter that meets the requirements of the surrounding noise level and voltage detection accuracy.

  (2) The electrical path connecting the plurality of filters 30a, 30b, 30c and the output terminal of the voltage detection means (differential amplifier circuit 20) is a path with a fixed impedance. In this case, the analog signal can be input to the filter easily and quickly compared to the case where the impedance is made variable by providing a switch or the like, and thus the output value of the filter can be converged quickly. It becomes. Further, the configuration can be simplified as compared with a case where a switch or the like is provided in the electrical path.

  (3) A zero point detection process for detecting the output voltage of the differential amplifier circuit 20 is performed in a state where both the high voltage side switching elements S0 to S7 and the low voltage side switching elements Sa and Sb are opened, and zero point detection is performed. A filter 30a having a lower transmission frequency during processing than when detecting a block voltage was used. As a result, the noise removal function can be enhanced during the zero point detection process in which the influence of noise becomes particularly significant. Further, at the time of normal voltage detection, it is possible to shorten the time required for the output value of the filter to converge by weakening the noise removal function of the filter. As a result, the low-voltage side switching elements Sa and Sb are closed. Maintenance time and voltage detection time can be shortened. In particular, in the present embodiment, since the low-voltage side switching elements Sa and Sb are configured by photo MOS relays, a large amount of power is required to close the low-voltage side switching elements Sa and Sb. By shortening the closing period, power consumption can be reduced.

  (4) At the time of detecting the block voltage, a filter having a higher transmission frequency when the power conversion circuit (inverter 14) is stopped than when driving is used. This shortens the convergence time of the output value of the filter by weakening the noise removal effect under a situation where noise is assumed not to be significant. Thereby, voltage detection time can be shortened. In particular, in the present embodiment, since the low-voltage side switching elements Sa and Sb are configured by photo MOS relays, a large amount of power is required to close the low-voltage side switching elements Sa and Sb. By shortening the closing period, power consumption can be reduced.

  (5) The filters 30a, 30b, and 30c are configured by RC circuits. Thereby, a filter can be comprised with a simple structure.

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

  In the present embodiment, processing for diagnosing the presence or absence of abnormality in the filters 30a, 30b, and 30c is performed. FIG. 5 shows the procedure of the diagnosis processing for the presence or absence of the abnormality according to the present embodiment. This process is repeatedly executed by the microcomputer 40 at a predetermined cycle, for example.

  In this series of processing, first, in step S30, it is determined whether or not a diagnosis execution condition is satisfied. Here, the diagnosis execution condition may be, for example, a condition indicating that the vehicle activation switch is immediately after being turned on. For example, it may be a condition that a predetermined time has elapsed since the previous execution of the abnormality diagnosis. If it is determined in step S30 that the execution condition is satisfied, the output voltage value of the differential amplifier circuit 20 is increased in step S32. This can be done by turning on the low-voltage side switching elements Sa and Sb after charging the flying capacitor 16 so that a positive voltage is applied to the non-inverting input terminal of the operational amplifier 21.

  In a succeeding step S34, the time counting operation of the counter T that times the time since the low-voltage side switching elements Sa and Sb are turned on is started. If it is determined that the specified time Tth has elapsed since the time when the low-voltage side switching elements Sa and Sb were turned on (step S36: YES), the output voltages Va, Vb, and 30b of the filters 30a, 30b, and 30c are determined in step S38. It is determined whether or not Vc has a relationship of “Vc> Vb> Va”. This process is for determining whether or not the filters 30a, 30b, and 30c are normal. That is, if these are normal, as shown in FIG. 6, the rising speed at which the output voltage rises after the low-voltage side switching elements Sa and Sb are turned off decreases in the order of the output voltages Vc, Vb, and Va. For this reason, in the present embodiment, the specified time Tth is made shorter than the time required for the convergence of the output voltage Vb of the filter 30b, thereby increasing based on the magnitude comparison of the output voltages Va, Vb, Vc. Understand the speed relationship.

  If an affirmative determination is made in step S38, it is determined in step S40 that the filters 30a, 30b, and 30c are normal. On the other hand, if a negative determination is made in step S38, the filters 30a, 30b, and 30c are determined in step S42. It is judged that at least one is abnormal.

  In addition, when the process of said step S40, S42 is completed, or when negative determination is made in step S30, this series of processes is once complete | finished.

  According to this embodiment described in detail above, the following effects can be obtained in addition to the effects (1) to (5) of the first embodiment.

  (6) Based on the comparison of the change speeds of the output values of the plurality of filters 30a, 30b, 30c when the same voltage is detected by the differential amplifier circuit 20, the presence or absence of abnormality of these filters is diagnosed. Thereby, the presence or absence of abnormality of the filters 30a, 30b, and 30c can be diagnosed without adding new parts.

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

  In each of the above embodiments, the three filters 30a, 30b, and 30c are provided as low-pass filters, but the present invention is not limited to this. For example, only the filters 30a and 30b may be provided, the filter 30a may be used at the time of zero point detection processing, and the filter 30b may be used at the time of block voltage detection. Further, for example, only the filters 30b and 30c may be provided, and the filter 30b may be used when the inverter 14 is driven and the zero point detection process among the block voltage detection, and the filter 30c may be used when the inverter 14 is stopped.

  In each of the above embodiments, the zero point detection process is performed in a state where the high voltage side switching elements S0 to S7 and the low voltage side switching elements Sa and Sb constituting the multiplexer MPX are opened, but the present invention is not limited to this. For example, the zero point detection process may be performed in a period in which two adjacent high-voltage side switching elements S0 to S7 constituting the multiplexer MPX are closed (charging period of the flying capacitor 16).

  The means for diagnosing the presence / absence of the filter abnormality based on the comparison of the change rate of the output value of the filter is not limited to that exemplified in the second embodiment. For example, the presence or absence of an abnormality may be diagnosed based on a comparison of time required for the output value to become a steady value. In this case, it may be determined as normal when the required time becomes shorter in the order of the output value of the filter 30a, the output value of the filter 30b, and the output value of the filter 30c.

  The means for diagnosing the presence / absence of filter abnormality is not limited to diagnosing the presence / absence of abnormality based on the comparison of the change rate of the output value of the filter. For example, it may be a means for diagnosing the presence or absence of an abnormality based on a comparison between steady values of output values.

  In each of the above embodiments, the charging polarity of the flying capacitor 16 is set to be reversed, but the present invention is not limited to this. For example, the charging polarity can be fixed by not sharing the path connecting the negative electrode on the potential side and the positive electrode on the low potential side of the pair of blocks adjacent to each other to the flying capacitor 16. It becomes.

  If the input possible voltage of the A / D converter 42 covers the detection target voltage (block voltage), the differential amplifier circuit 20 may not be provided. However, at this time, when the polarity of the input voltage of the A / D converter 42 is fixed, the charging polarity of the flying capacitor 16 is set not to be inverted. In this case, voltage detection means for outputting an analog signal corresponding to the voltage of the battery serves as an electrical path connecting the low-voltage side switching element Sa and the filters 30a, 30b, 30c.

  In each of the above embodiments, the number of flying capacitors is one. However, the number is not limited to this. For example, two may be used. Further, as described in Patent Document 1, four or three or more may be used.

  -As what applies a voltage to the flying capacitor 16, not only the block Bi but the battery cell 12 grade | etc., May be sufficient.

  The voltage detection means for outputting an analog signal corresponding to the battery voltage is not limited to one that outputs an analog signal corresponding to the voltage of the flying capacitor 16. For example, as described in Japanese Patent Application Laid-Open No. 2000-134818, the potential difference between the positive electrode potential of each battery cell constituting the assembled battery 10 and the negative electrode potential of the assembled battery 10 is divided by a resistor, It may be a means for outputting a partial pressure value.

  In each of the above embodiments, the configuration in which the assembled battery 10 is directly connected to the inverter 14 is illustrated. However, the present invention is not limited to this, and a boost converter that boosts the voltage of the assembled battery 10 is connected to the assembled battery 10. The output terminal may be connected to the inverter.

  In the above embodiments, the filter is switched between when the inverter IV is driven and when it is stopped, but the present invention is not limited to this. For example, the filter may be further switched depending on whether or not the step-down converter that steps down the voltage of the assembled battery 10 and applies it to the power supply (low voltage battery) of the in-vehicle auxiliary machine is driven. In this case, four or more types of filters may be provided. Further, in each of the above embodiments, it is assumed that the switching frequency of the inverter IV is the lowest among the power conversion circuits constituting the in-vehicle high-voltage system. However, the present invention is not limited to this, for example, the switching frequency of the step-down converter is lower. In each of the above embodiments, the filter may be switched in accordance with driving or stopping of the step-down converter instead of the inverter IV.

  The low-pass filter is not limited to a pair consisting of a resistor and a capacitor, and may be, for example, a resistor and a capacitor connected in series at a connection point between the resistor and the capacitor. The low-pass filter is not limited to the RC circuit, and may be any appropriate hardware means having a function of removing a high-frequency signal, such as an RCL circuit.

  The battery cell 12 is not limited to a secondary battery, and may be a fuel cell, for example. Furthermore, the battery that is a voltage detection target is not limited to the assembled battery 10. In view of the presence of various noises in the vehicle, it is also effective to apply the present invention when detecting the voltage of the power source (low voltage battery) of the in-vehicle auxiliary machine.

  In each of the above embodiments, the present invention is applied to a hybrid vehicle. However, the present invention is not limited thereto, and the present invention may be applied to, for example, an electric vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Battery pack, 12 ... Battery cell, 16 ... Flying capacitor, 20 ... Differential amplifier circuit, 30a, 30b, 30c ... Filter, 42 ... A / D converter, B0-B7 ... Block, S0-S7 ... High voltage side Switching element, Sa, Sb... Low voltage side switching element.

Claims (8)

Voltage detection means for outputting an analog signal corresponding to the voltage of a battery mounted on a vehicle, a low-pass filter for inputting an analog signal output from the voltage detection means, and analog digital for converting the output of the low-pass filter into a digital signal In a voltage detection device comprising a conversion means,
The low-pass filter comprises a plurality of filters connected in parallel between the voltage detection means and the analog-digital conversion means,
The plurality of filters include those having different transmission characteristics of frequency signals ,
The battery exchanges power with a rotating machine as an in-vehicle main machine through a power conversion circuit,
The analog-to-digital conversion means is characterized in that the conversion target at the time of detecting the voltage of the battery is an analog signal output by a filter having a higher transmission frequency when the power conversion circuit is stopped than when it is driven. Voltage detection device. Claim 1, characterized in that the basis of the voltage comparison of the respective output values of said plurality of filters in detecting the same voltage by the detecting means, further comprising abnormality diagnosis means for diagnosing the presence or absence of these filters abnormal voltage detecting device according to. Voltage detection means for outputting an analog signal corresponding to the voltage of a battery mounted on a vehicle, a low-pass filter for inputting an analog signal output from the voltage detection means, and analog digital for converting the output of the low-pass filter into a digital signal In a voltage detection device comprising a conversion means,
The low-pass filter comprises a plurality of filters connected in parallel between the voltage detection means and the analog-digital conversion means,
The plurality of filters include those having different transmission characteristics of frequency signals,
A voltage detecting device further comprising an abnormality diagnosing means for diagnosing the presence or absence of an abnormality of the filters based on comparison of output values of the plurality of filters when the same voltage is detected by the voltage detecting means. . The battery constitutes an in-vehicle high voltage system,
A capacitor;
High voltage side opening / closing means for opening / closing between the battery and the capacitor;
The voltage detection device according to any one of claims 1 to 3, further comprising a low-voltage side opening / closing means for opening / closing the capacitor and the voltage detection means. Means for performing a zero point detection process for detecting an output voltage of the voltage detection means in a state where both the high voltage side opening and closing means and the low voltage side opening and closing means are opened;
The analog-digital conversion means, according to claim 4, wherein converting the analog signal output from the low transmittance frequency filter than when the detection direction of the time zero point detection processing of the voltage of the battery to a digital signal Voltage detection device. Voltage detection means for outputting an analog signal corresponding to the voltage of a battery mounted on a vehicle, a low-pass filter for inputting an analog signal output from the voltage detection means, and analog digital for converting the output of the low-pass filter into a digital signal In a voltage detection device comprising a conversion means,
The low-pass filter comprises a plurality of filters connected in parallel between the voltage detection means and the analog-digital conversion means,
The plurality of filters include those having different transmission characteristics of frequency signals,
The battery constitutes an in-vehicle high voltage system,
A capacitor;
High voltage side opening / closing means for opening / closing between the battery and the capacitor;
Low voltage side opening and closing means for opening and closing between the capacitor and the voltage detection means,
Means for performing a zero point detection process for detecting an output voltage of the voltage detection means in a state where both the high voltage side opening and closing means and the low voltage side opening and closing means are opened;
The voltage detection apparatus according to claim 1, wherein the analog-digital conversion means converts an analog signal output from a filter having a lower transmission frequency in the zero point detection process than in the battery voltage detection into a digital signal. The voltage detection apparatus according to any one of claims 1 to 6, wherein an electrical path connecting the plurality of filters and an output terminal of the voltage detection means is a path having a fixed impedance. The filter, the voltage detecting device according to any one of claims 1 to 7, characterized in that it is constituted by an RC circuit.

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