JP6907066B2 - Impedance measuring device - Google Patents

Description

The present invention relates to an impedance measuring device for measuring the internal impedance of a battery.

As a current supply device provided in this type of impedance measuring device and supplying a measuring current to a battery to be measured, the measuring current energizing device disclosed in Patent Document 1 below is known. This measured current energizer includes an AC reference power generator, an error amplifier, a SEPP (Single Ended Push-Pull) circuit having an NPN transistor and a PNP transistor for current control, a current detection resistor, a capacitor as a charge storage element, and a drive. It is composed of a power supply.

Specifically, the AC reference power supply generator generates an AC signal having a desired frequency, and is connected to the + input terminal (non-inverting input terminal) of the error amplifier. The output terminal of the error amplifier is connected to the base terminal of the NPN transistor and the PNP transistor. The collector terminal of the NPN transistor and the collector terminal of the PNP transistor are connected via a drive power supply. That is, the collector terminal of the NPN transistor is connected to the high potential side output terminal of the drive power supply, and the collector terminal of the PNP transistor is connected to the low potential side output terminal of the drive power supply. also. The emitter terminal of the NPN transistor and the emitter terminal of the PNP transistor, which are directly connected to each other, are connected to the anode terminal of the battery (storage battery to be measured) via a current detection resistor. Further, the emitter terminal of the NPN transistor and the emitter terminal (connection point between the emitter terminals) of the PNP transistor are connected to the − input terminal (inverting input terminal) of the error amplifier. Further, the collector terminal of the PNP transistor is connected to the cathode terminal of the battery via a capacitor.

This measured current energizing device operates so that the voltage generated in the current detection resistor and the voltage of the AC reference power supply generator become equal to each other. Here, since the resistance value of the current detection resistance is constant, the measured current of the constant current AC component proportional to the voltage of the AC reference voltage generator is energized to the battery.

In this case, in this measurement current energizing device, a capacitor is connected in series with the battery. Therefore, the measured current of the constant current AC component energized between the anode and the cathode of the battery by the AC signal generated from the AC reference power source generator has one polar component (negative electrode component) from the battery. When the discharge current flows, the battery and the capacitor form a closed loop circuit, and the electric charge at the time of discharge is stored in the capacitor. On the other hand, when the measured current of the constant current AC component energized between the anode and the cathode of the battery has the other polar component (positive electrode component) and the charging current flows through the battery, the battery, the capacitor, and the driving power supply To form a closed loop circuit, and the charge stored in the capacitor is discharged to the battery. Therefore, in this measurement current energizer, even if the output voltage of the drive power supply is set sufficiently lower than the battery voltage, the potential of the capacitor rises after a certain period of time has passed after the start-up, and the output voltage of the drive power supply becomes the same. Since the sum with the potential of the capacitor becomes higher than the voltage of the battery and the charging current flows through the battery, it is possible to energize the measurement current of the constant current AC component between the anode and cathode of the battery. Become. From this, the electromotive force measured by measuring the electromotive force generated between one cell terminal of the battery with a voltmeter by configuring the impedance measuring device using the measured current energizing device and the voltmeter. It is possible to measure the internal impedance of the battery based on the measured current and the measured current.

Japanese Unexamined Patent Publication No. 2003-121515 (Pages 3-4, Fig. 1)

However, the impedance measuring device having the above-mentioned measuring current energizing device has the following problems to be solved. That is, although it is not specified in the above-mentioned Patent Document 1 from which power is supplied to operate the driving power source constituting the measurement current energizing device, for those skilled in the art, the impedance measuring device is used. In the battery-powered configuration, the drive power supply is operated based on the power constantly supplied from the built-in battery, and in the impedance measuring device in the commercial power supply-driven configuration, the drive power supply is operated based on the power constantly supplied from the commercial power supply. It is considered that it is common to make the configuration.

In recent years, it has been desired for an impedance measuring device to further extend the battery drive time by reducing the power supplied from the battery as much as possible in the battery-powered configuration, and in the commercial power-powered configuration. It is desired to reduce the electric power supplied from the commercial power source as much as possible, but as described above, it is provided with a measurement current energizing device having a drive power source that needs to constantly supply electric power from the battery or the commercial power source. There is a problem that it is difficult to meet this demand with the impedance measuring device.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an impedance measuring device capable of reducing the electric power supplied from a battery or a commercial power source to a driving power source.

In order to achieve the above object, the impedance measuring device according to claim 1 is connected to a first connection terminal to which the anode of the battery to be measured is connected, a second connection terminal to which the cathode of the battery is connected, and the second connection terminal. A capacitor to which one end is connected, a low potential side terminal is connected to the other end of the capacitor, and the AC current is measured based on the AC signal input to the input terminal by operating at the supply voltage supplied to the high potential side terminal. A current supply unit having a SEPP circuit that generates and outputs the output terminal to the first connection terminal, a drive power supply that generates the supply voltage and supplies the supply voltage to the high potential side terminal, a main power supply, and a control circuit. An impedance measuring device that measures the internal impedance of the battery based on the measured alternating current output to the battery via the first connection terminal and the voltage between the first connection terminal and the second connection terminal. The current supply unit has a switching circuit capable of outputting any one of the charging voltage of the capacitor and the DC power supply voltage output from the main power supply as the operating voltage of the driving power supply. When the charging voltage is equal to or higher than the first reference voltage within the operating voltage range of the driving power supply, the control circuit causes the switching circuit to output the charging voltage as the operating voltage, and the charging voltage is the operating voltage. When it is less than the first reference voltage, a voltage switching process for outputting the DC power supply voltage as the operating voltage to the switching circuit is executed.

The impedance measuring device according to claim 2 is the impedance measuring device according to claim 1, wherein the SEPP circuit is an NPN type in which a collector terminal is connected to the high potential side terminal and an emitter terminal is connected to the output terminal. It has a transistor and a PNP type transistor whose emitter terminal is connected to the emitter terminal of the NPN type transistor and whose collector terminal is connected to the low potential side terminal, and the control circuit is a collector of the NPN type transistor. A voltage control process for controlling the supply voltage of the driving power source is executed so that the collector-emitter voltage is maintained at a predetermined voltage while detecting the emitter-emitter voltage.

In the impedance measuring device according to claim 1, when the charging voltage of the capacitor is equal to or higher than the first reference voltage, a DC power supply is used as the operating voltage for the driving power supply that supplies the supply voltage to the SEPP circuit constituting the current supply unit. Not only the voltage, but also the charging voltage of the capacitor charged by the battery to be measured is used.

Therefore, according to this impedance measuring device, the power required for the main power supply to output the DC power supply voltage can be reduced by the amount of using the charging voltage. Therefore, when the main power supply has a battery, it can be reduced. , The power consumption of the battery can be reduced by the amount of using the charging voltage, and when the main power supply is configured to use the commercial power supply, the power consumption of the commercial power supply can be reduced by the amount of using the charging voltage. ..

In the impedance measuring device according to claim 2, the SEPP circuit includes an NPN type transistor and a PNP type transistor, and the control circuit detects the collector-emitter voltage of the NPN type transistor while detecting the collector-emitter. A voltage control process for controlling the supply voltage of the driving power source is executed so that the emitter-to-emitter voltage is maintained at a predetermined voltage.

Therefore, according to this impedance measuring device, the voltage value of the supply voltage is increased or decreased according to the increase or decrease of the voltage value of the output voltage output from the SEPP circuit. Compared with the configuration supplied from the power supply to the SEPP circuit, the power consumption of the NPN type transistor can be significantly reduced. Further, as a result, the heat generation in the NPN type transistor can be significantly reduced.

It is a block diagram of the impedance measuring apparatus 1. It is a waveform diagram for demonstrating the operation of the current supply part 4 of FIG. It is a waveform diagram for demonstrating the operation in the period Ta in FIG. It is a waveform diagram for demonstrating the operation in the period Tb in FIG.

Hereinafter, embodiments of the impedance measuring device will be described with reference to the accompanying drawings.

First, the configuration of the impedance measuring device 1 as the impedance measuring device will be described with reference to FIG.

The impedance measuring device 1 includes a first connection terminal 2, a second connection terminal 3, a current supply unit 4, a current detection unit 5, a voltage detection unit 6, a processing unit 7, and an output unit 8. The impedance (internal impedance Z) of the battery 51 as a measurement target to which the 52 is connected and the cathode 53 is connected to the second connection terminal 3 can be measured.

Specifically, the current supply unit 4 is, for example, a capacitor 11, a SEPP circuit 12, a drive power supply 13, a signal source 14, a constant current circuit 15, a switching circuit 16, a main power supply 17, and a part of the processing unit 7. The control circuit 18 is also provided, and the measured alternating current I is output to the battery 51 connected between the first connection terminal 2 and the second connection terminal 3. In this example, one end of the capacitor 11 is connected to the second connection terminal 3 (in this example, the second connection terminal 3 via the internal ground G).

The SEPP circuit 12 includes an NPN-type transistor 21 (NPN-type bipolar transistor or n-channel field-effect transistor (FET); hereinafter, simply referred to as a transistor 21) and a PNP-type transistor 22 (PNP-type bipolar transistor). A p-channel type field effect transistor (FET); hereinafter simply referred to as a transistor 22) is provided, and control terminals (base terminal for bipolar transistor and gate terminal for FET) are connected to each other and their first outputs are output from each other. The terminals (emitter terminal for bipolar transistor and source terminal for FET) are connected to each other. Further, in the SEPP circuit 12, each control terminal connected to each other functions as an input terminal 23 in the SEPP circuit 12, and each first output terminal connected to each other functions as an output terminal 24 in the SEPP circuit 12. Further, in the SEPP circuit 12, the second output terminal (collector terminal in the bipolar transistor and drain terminal in the FET) of the transistor 21 located on the high potential side functions as the high potential side terminal 25 in the SEPP circuit 12, and is on the low potential side. The second output terminal (collector terminal in the bipolar transistor and drain terminal in the FET) of the transistor 22 located at the position functions as a low potential side terminal 26 in the SEPP circuit 12. In this case, the low potential side terminal 26 is connected to the other end of the capacitor 11.

In the SEPP circuit 12 of this example, as shown in FIG. 1 as an example, both the transistor 21 and the transistor 22 are composed of bipolar transistors. With this configuration, in order to facilitate understanding, the SEPP circuit 12 is the same as the voltage input to the input terminal 23, if the base-emitter voltage of the bipolar transistors constituting the transistors 21 and 22 can be ignored. The voltage of the voltage value is output from the output terminal 24 as the output voltage Vout. That is, the SEPP circuit 12 of this example operates in a state where the input terminal 23 and the output terminal 24 have the same potential.

The drive power supply 13 is composed of, for example, a DC-DC converter (also simply referred to as a converter), generates a supply voltage Vsp based on the operating voltage Vop output from the switching circuit 16, and has a high potential of the SEPP circuit 12. It is supplied to the side terminal 25. When the operating voltage Vop is equal to or higher than the first reference voltage Vr within the operating voltage range, the driving power supply 13 operates normally to generate a supply voltage Vsp. In this example, in order to give hysteresis to the switching operation with respect to the switching circuit 16, the first reference voltage Vr is the lower limit first reference voltage Vr1 as the first reference voltage Vr and the upper limit Vr as the first reference voltage Vr. It is defined by 1 reference voltage Vr2 (> Vr1) (see FIG. 2). Further, the drive power supply 13 is configured so that the voltage value of the supply voltage Vsp can be controlled by the control circuit 18. The signal source 14 generates an AC signal (for example, a sine wave signal having a constant (known) amplitude and a constant (known) frequency) S1 with reference to the internal ground G, and from its output terminal (not shown). Output.

The constant current circuit 15 is, for example, an operational amplifier 31 in which an output terminal is connected to an input terminal 23 of the SEPP circuit 12, and a resistor 32 connected between the non-inverting input terminal of the operational amplifier 31 and the output terminal of the signal source 14. , Two feedback resistors 33, 34, SEPP circuit, which are arranged in series between the output terminal 24 of the SEPP circuit and the internal ground G and whose connection points are connected to the inverting input terminal of the operational amplifier 31. A detection resistor 35 connected between the output terminal 24 and the first connection terminal 2, an operational amplifier 36 configured as a voltage follower circuit and having a non-inverting input terminal connected to the first connection terminal 2, and one end performing an operational amplifier. It is configured to include a resistor 37 connected to the output terminal of the amplifier 36 and the other end connected to the non-inverting input terminal of the operational amplifier 31. Further, in the SEPP circuit 12 of this example, since the input terminal 23 and the output terminal 24 have the same potential, the output terminals of the operational amplifier 31 are equivalently feedback resistors 33 and 34 via the SEPP circuit 12. It is connected to the end opposite to the internal ground G side in the series circuit of. With this configuration, the operational amplifier 31 is a non-inverting amplifier that amplifies and outputs the signal input to the non-inverting input terminal at a constant amplification factor (known) defined by each resistance value of the feedback resistors 33 and 34. Function.

In the constant current circuit 15, the operational amplifier 36 configured as a voltage follower circuit outputs a voltage having the same voltage value as the battery voltage Vbat (hereinafter, also referred to as the battery voltage Vbat) from its output terminal to the resistor 37 with low impedance. .. In this case, since the resistor 37 and the resistor 32 are arranged in series between the output terminal of the arithmetic amplifier 36 and the output terminal of the signal source 14, the AC signal is transmitted from the output terminal of the signal source 14. In the state where S1 is output, at the connection point of the resistor 37 and the resistor 32, the AC signal S1 is added to the DC voltage component (positive voltage) formed by dividing the battery voltage Vbat by each resistance value of the resistor 37 and the resistor 32. Is divided by the resistance values of the resistance 37 and the resistance 32 to generate a voltage on which an AC voltage component is superimposed. The operational amplifier 31 in which the non-inverting input terminal is connected to the connection point of the resistor 37 and the resistor 32 non-inverting the voltage generated in this way at the above-mentioned constant amplification factor and outputs the output voltage Vout.

With this configuration, the constant current circuit 15 raises / lowers the voltage output from the operational amplifier 31, that is, the output voltage Vout output from the output terminal 24 of the SEPP circuit 12 according to the rise / fall of the battery voltage Vbat. By controlling the voltage across the detection resistor 35 to be constant, it is possible to maintain the current value of the measured alternating current I constant.

The switching circuit 16 is selected by any one of the charging voltage Vc of the capacitor 11 and the DC power supply voltage Vdc output from the main power supply 17 (selected by the control circuit 18) by controlling the switching state by the control circuit 18. On the other hand) is output as the operating voltage Vop of the driving power supply 13. Further, the switching circuit 16 is composed of a relay and a semiconductor switch such as a bipolar transistor or FET.

The main power supply 17 generates and outputs a DC power supply voltage Vdc for operation for each component constituting the impedance measuring device 1. In this case, the main power supply 17 may be composed of a single battery that directly outputs the DC power supply voltage Vdc, or a power supply that generates and outputs the above-mentioned DC power supply voltage Vdc based on the battery and the voltage output from the battery. It may be configured by a circuit, or may be configured by a power supply circuit that outputs a DC power supply voltage Vdc based on the power supplied from an external commercial power supply.

As an example in this example, the control circuit 18 constitutes a processing unit 7 together with a measurement circuit 9 described later, and executes a voltage switching process and a voltage control process. In this case, in the voltage switching process, the control circuit 18 is defined in advance while detecting, for example, the difference voltage (Vout-Vc, that is, the collector-emitter voltage of the transistor 22) between the output voltage Vout and the charging voltage Vc. By comparing with the reference voltage, it is determined whether or not the charging voltage Vc of the capacitor 11 is equal to or higher than the first reference voltage Vr within the operating voltage range of the driving power supply 13 (in this example, the charging voltage Vc is When it rises and reaches the upper limit first reference voltage Vr2, or the charging voltage Vc drops and reaches the lower limit first reference voltage Vr1), it is equal to or higher than the first reference voltage Vr (in this example). , From when the upper limit first reference voltage Vr2 is reached until the charging voltage Vc drops and reaches the lower limit first reference voltage Vr1), the switching circuit is controlled by controlling the switching state of the switching circuit 16. The charging voltage Vc is output to 16 as the operating voltage Vop. Further, in the voltage switching process, the control circuit 18 starts when the lowered charging voltage Vc is less than the first reference voltage Vr (in this example, when the lowered charging voltage Vc reaches the lower limit first reference voltage Vr1). During the period until the charging voltage Vc rises and reaches the upper limit first reference voltage Vr2), the DC power supply voltage Vdc is set to the switching circuit 16 by controlling the switching state of the switching circuit 16. Is output as. Further, in the voltage control process, the control circuit 18 detects the difference voltage (Vsp-Vout, that is, the collector-emitter voltage of the transistor 21) between the supply voltage Vsp and the output voltage Vout, and defines the difference voltage in advance. The supply voltage Vsp is controlled by the drive power supply 13 so as to be maintained at the set voltage (the voltage value of the supply voltage Vsp is changed).

The current detection unit 5 is configured to include, for example, a differential amplifier and an A / D converter (neither of which is shown). In the current detection unit 5, the differential amplifier detects the difference voltage (Vout-Vbat, that is, the voltage between both ends of the detection resistor 35) between the output voltage Vout and the battery voltage Vbat, amplifies and outputs the voltage, and outputs the A / D. By sampling the voltage output from the differential amplifier by the converter, the current waveform data Di indicating the instantaneous value of the waveform of the measured AC current I is output.

The voltage detection unit 6 includes, for example, an amplifier and an A / D converter (neither of which is shown). In the voltage detection unit 6, the amplifier amplifies the battery voltage Vbat at a predetermined amplification factor and outputs it, and the A / D converter samples the voltage output from the amplifier (with the A / D converter of the current detection unit 5). By sampling at the same timing), the voltage waveform data Dv showing the instantaneous value of the waveform of the battery voltage Vbat is output.

The processing unit 7 (as an example in this example, the measurement circuit 9 that constitutes the processing unit 7 together with the control circuit 18 described above) is composed of a computer, a DSP, or the like, and is based on the current waveform data Di and the voltage waveform data Dv. (Specifically, based on the waveform data of the AC current component in the current waveform represented by the current waveform data Di and the waveform data of the AC voltage component in the voltage waveform represented by the voltage waveform data Dv), the battery 51. The internal impedance Z of the above is calculated and output to the output unit 8.

As an example, the output unit 8 is composed of a display device such as an LCD, and displays the internal impedance Z output from the processing unit 7 on the display screen. The output unit 8 may be configured by various interface circuits instead of the display device. For example, the removable media may store the internal impedance Z as a media interface circuit, or the output unit 8 may be an external device via a network as a network interface circuit. It is also possible to adopt a configuration in which the internal impedance Z is transmitted to the interface.

Next, the operation of the impedance measuring device 1 will be described. For ease of understanding, it is assumed that the charging voltage Vc of the capacitor 11 is initially zero volt, the battery 51 is in a substantially fully charged state, and the DC voltage component of the battery voltage Vbat is constant.

In this state, the current supply unit 4 determines that the charging voltage Vc is less than the lower limit first reference voltage Vr1 in the voltage switching process in which the control circuit 18 starts executing immediately after the impedance measuring device 1 is started. By detecting and controlling the switching state of the switching circuit 16 based on the detection result, the switching circuit 16 is made to output the DC power supply voltage Vdc as the operating voltage Vop. As a result, the drive power supply 13 operates at the DC power supply voltage Vdc supplied as the operating voltage Vop, generates a supply voltage Vsp, and supplies the supply voltage Vsp to the high potential side terminal 25 of the SEPP circuit 12. The control circuit 18 causes the switching circuit 16 to output the DC power supply voltage Vdc as the operating voltage Vop during the period Ta (see FIG. 2) until it detects that the charging voltage Vc has reached the first reference voltage Vr2. Continue operation.

On the other hand, in the circuit (capacitor 11, SEPP circuit 12, signal source 14 and constant current circuit 15) for outputting the measured alternating current I to the battery 51, the constant current circuit 15 is output from the signal source 14. The AC signal S1 is amplified and output to the SEPP circuit 12, and the signal output from the constant current circuit 15 by the SEPP circuit 12 is output as an output voltage Vout from the first connection terminal 2 to the battery 51 via the detection resistor 35.

As shown in FIG. 2, this output voltage Vout is the voltage drop (AC signal which is a sinusoidal wave) generated in the detection resistance 35 when the measurement AC current I flows through the detection resistance 35 in the battery voltage Vbat (DC voltage component). The voltage is a superposition of an AC voltage component (which changes in synchronization with S1). Therefore, in this period Ta, as shown in FIG. 3, the transistor 21 of the SEPP circuit 12 is turned off and the transistor 21 of the SEPP circuit 12 is turned off during the period when the output voltage Vout is lower than the battery voltage Vbat (the period from time t0 to time t1). Since the transistor 22 is turned on, the measured AC current I is transmitted from the anode 52 of the battery 51 to the first connection terminal 2, the detection resistor 35, the output terminal 24 of the SEPP circuit 12, the transistor 22, and the low potential of the SEPP circuit 12. It flows through the side terminal 26, the capacitor 11, the internal ground G, and the second connection terminal 3 to the path (closed loop circuit) to the cathode 53 of the battery 51. As a result, the capacitor 11 is charged, so that the charging voltage Vc rises.

On the other hand, in the next period in this period Ta (as shown in FIG. 3, a period in which the output voltage Vout exceeds the battery voltage Vbat (a period from time t1 to time t2)), the transistor 21 of the SEPP circuit 12 is in the ON state. And the transistor 22 is turned off, the measured AC current I is detected by the output terminal of the drive power supply 13, the high potential side terminal 25 of the SEPP circuit 12, the transistor 21, and the output terminal 24 of the SEPP circuit 12. The current flows through the resistor 35, the first connection terminal 2, the anode 52 of the battery 51, the cathode 53 of the battery 51, the second connection terminal 3, and the internal ground G to the drive power supply 13 (closed loop circuit). Since the capacitor 11 is not included in this path (there is no charge / discharge operation for the capacitor 11), the charging voltage Vc of the capacitor 11 is maintained substantially constant. As a result, in this period Ta, the operation in the period from time t0 to time t1 and the operation in the period from time t1 to time t2 are repeated, so that charging is performed as shown in FIGS. As a whole, the voltage Vc gradually increases (for example, by ΔVc1) every cycle for the AC voltage component of the output voltage Vout.

Further, in the current supply unit 4, in the voltage control process in which the control circuit 18 starts execution immediately after the impedance measuring device 1 is started, the difference voltage (Vsp-Vout) between the supply voltage Vsp and the output voltage Vout. That is, while detecting the collector-impedance voltage of the transistor 21, as shown in FIGS. 2 and 3, the supply voltage to the drive power supply 13 is maintained so that the differential voltage is maintained at a predetermined voltage. Control Vsp (change the voltage value of supply voltage Vsp). The "predetermined voltage" in this case is defined as a voltage exceeding the minimum voltage value at which the transistor 21 can operate in the linear region. As shown in FIGS. 2 and 3, when the control circuit 18 executes this voltage control process, the voltage value of the supply voltage Vsp is increased or decreased according to the increase or decrease of the voltage value of the output voltage Vout. As shown by a broken line in 3, the power consumption of the transistor 21 is significantly higher than that of the configuration in which the drive power supply 13 supplies the high potential side terminal 25 of the SEPP circuit 12 with the supply voltage Vsp constant. It is possible to reduce the voltage.

As shown in FIG. 2, when the charging voltage Vc gradually increasing in this way exceeds the lower limit first reference voltage Vr1 and reaches the first reference voltage Vr2, the control circuit 18 detects this and determines it. Period Ta (period in which the DC power supply voltage Vdc is output to the switching circuit 16 as the operating voltage Vop) is terminated, and the operation of outputting the charging voltage Vc to the switching circuit 16 as the operating voltage Vop is executed. Start Tb. During this period Tb, the driving power supply 13 operates at the charging voltage Vc supplied as the operating voltage Vop, generates the supply voltage Vsp, and supplies the supply voltage Vsp to the high potential side terminal 25 of the SEPP circuit 12.

In the circuit (capacitor 11, SEPP circuit 12, signal source 14 and constant current circuit 15) for outputting the measured alternating current I to the battery 51, each component has the same period Tb as that of the period Ta. Perform the same above actions. Therefore, as shown in FIGS. 2 and 4, in the output voltage Vout in the period Tb, the AC voltage component that changes in synchronization with the AC signal S1 which is a sinusoid is the battery voltage Vbat, as in the case of the period Ta. The supply voltage Vsp is also a voltage whose voltage value increases or decreases according to an increase or decrease of the voltage value of the output voltage Vout.

Therefore, even in this period Tb, as shown in FIG. 4, the transistor 21 of the SEPP circuit 12 is turned off during the period when the output voltage Vout is lower than the battery voltage Vbat (the period from the time t10 to the time t11). Moreover, since the transistor 22 is turned on, the measured AC current I is low from the anode 52 of the battery 51 to the first connection terminal 2, the detection resistor 35, the output terminal 24 of the SEPP circuit 12, the transistor 22, and the SEPP circuit 12. It flows through the potential side terminal 26, the capacitor 11, the internal ground G, and the second connection terminal 3 to the path to the cathode 53 of the battery 51. As a result, the capacitor 11 is charged, so that the charging voltage Vc rises. However, since energy is constantly supplied from the capacitor 11 to the drive power supply 13, the degree of increase is slightly lower than that during the period Ta shown in FIG.

On the other hand, in the next period in this period Tb (as shown in FIG. 4, the period when the output voltage Vout exceeds the battery voltage Vbat (the period from time t1 to time t2)), the transistor 21 of the SEPP circuit 12 is in the ON state. And the transistor 22 is turned off, the measured AC current I is detected by the output terminal of the drive power supply 13, the high potential side terminal 25 of the SEPP circuit 12, the transistor 21, and the output terminal 24 of the SEPP circuit 12. The current flows through the resistor 35, the first connection terminal 2, the anode 52 of the battery 51, the cathode 53 of the battery 51, the second connection terminal 3, and the internal ground G to the drive power supply 13. Although the capacitor 11 is not included in this path (that is, there is no direct charge / discharge operation to the capacitor 11 by the measured alternating current I), energy is constantly supplied from the capacitor 11 to the drive power supply 13. Therefore, the charging voltage Vc gradually decreases. As a result, in this period Tb, the operation in the period from time t10 to time t11 and the operation in the period from time t11 to time t12 are repeated, so that charging is performed as shown in FIGS. As a whole, the voltage Vc gradually decreases (for example, ΔVc2 each) for each cycle of the AC voltage component of the output voltage Vout.

As shown in FIG. 2, when the charging voltage Vc gradually reduced in this way reaches the lower limit first reference voltage Vr1, the control circuit 18 detects this and the period Tb (relative to the switching circuit 16). The period for outputting the charging voltage Vc as the operating voltage Vop) is terminated, and the period Tc for executing the operation of outputting the DC power supply voltage Vdc as the operating voltage Vop to the switching circuit 16 is started. During this period Tc, each component of the current supply unit 4 performs the same operation as during the period Ta described above. As a result, as a whole, the charging voltage Vc gradually increases every cycle with respect to the AC voltage component of the output voltage Vout, as shown in FIG.

Further, when the charging voltage Vc gradually increased in this way reaches the first reference voltage Vr2 as shown in FIG. 2, the control circuit 18 detects this and Tc (switching circuit 16) during this period. The period for outputting the DC power supply voltage Vdc as the operating voltage Vop) is terminated, and the period Td for executing the operation of outputting the charging voltage Vc as the operating voltage Vop to the switching circuit 16 is started. During this period Td, each component of the current supply unit 4 performs the same operation as during the period Tb described above. As a result, as a whole, the charging voltage Vc gradually decreases every cycle with respect to the AC voltage component of the output voltage Vout, as shown in FIG.

In this way, the current supply unit 4 maintains the charging voltage Vc of the capacitor 11 at the first reference voltage Vr (specifically, between the lower limit first reference voltage Vr1 and the first reference voltage Vr2). The DC power supply voltage Vdc and the charging voltage Vc are alternately supplied to the driving power supply 13 as the operating voltage Vop, and the measured AC current I is continuously supplied to the battery 51.

Further, in the impedance measuring device 1, the current detecting unit 5 outputs the current waveform data Di indicating the instantaneous value of the waveform of the measured AC current I, and the voltage detecting unit 6 outputs the voltage indicating the instantaneous value of the waveform of the battery voltage Vbat. Waveform data Dv is output. In this case, in the waveform of the battery voltage Vbat, an AC voltage component having an amplitude corresponding to the magnitude of the internal impedance Z appears while being synchronized with the measured AC current I. In the processing unit 7 (measurement circuit 9 in this example), for example, the charging voltage Vc of the capacitor 11 is maintained at the first reference voltage Vr (specifically, the lower limit first reference voltage Vr1 and the first reference voltage Vr2). Based on the AC voltage component in the voltage waveform represented by the voltage waveform data Dv and the AC current component in the current waveform represented by the current waveform data Di in the period Tb, Tc, etc. , The internal impedance Z of the battery 51 is calculated and output to the output unit 8. The output unit 8 displays the internal impedance Z output from the processing unit 7 on the display screen in this way. As a result, the measurement of the internal impedance Z of the battery 51 by the impedance measuring device 1 is completed.

As described above, in this impedance measuring device 1, when the charging voltage Vc of the capacitor 11 is equal to or higher than the first reference voltage Vr (in this example, when the lower limit first reference voltage Vr1 or higher), the current supply unit 4 is configured. As the operating voltage Vop for the driving power supply 13 that supplies the supply voltage Vsp to the SEPP circuit 12, not only the DC power supply voltage Vdc but also the charging voltage Vc of the capacitor 11 charged by the battery 51 as the measurement target is used. Will be done. Therefore, according to the impedance measuring device 1, the power required for the main power supply 17 to output the DC power supply voltage Vdc can be reduced by the amount of using the charging voltage Vc, so that the main power supply 17 is a battery. When the configuration has, the power consumption of the battery can be reduced by the amount of using the charging voltage Vc, and when the main power supply 17 is configured to use the commercial power supply, the amount of the commercial power supply can be reduced by the amount of using the charging voltage Vc. Power consumption can be reduced.

Further, in the impedance measuring device 1, the SEPP circuit 12 is configured to include the transistors 21 and 22, and the control circuit 18 detects the collector-emitter voltage (Vsp-Vout) of the transistor 21 while detecting the transistor 21. A voltage control process for controlling the supply voltage Vsp of the drive power supply 13 is executed so that the collector-emitter voltage is maintained at a predetermined voltage. Therefore, according to the impedance measuring device 1, the voltage value of the supply voltage Vsp is also increased or decreased according to the increase or decrease of the voltage value of the output voltage Vout. Therefore, the drive power supply 13 keeps the voltage value of the supply voltage Vsp constant. Compared with the configuration supplied to the SEPP circuit 12 from the above, the power consumption in the transistor 21 can be significantly reduced. Further, as a result, the heat generated by the transistor 21 can be significantly reduced. However, it is also possible to adopt a configuration in which the drive power supply 13 supplies the SEPP circuit 12 with the supply voltage Vsp kept constant.

The current supply unit 4 adopts a configuration in which the charging voltage Vc of the capacitor 11 is used as it is as the operating voltage Vop of the driving power supply 13, but the present invention is not limited to this configuration. For example, although not shown, when the charging voltage Vc of the capacitor 11 is lower than the operating voltage Vop of the driving power supply 13, it is known to have, for example, a switching element, an inductor (or a step-up transformer), and a rectifying smoothing circuit. It is also possible to adopt a configuration in which a booster circuit is arranged between the capacitor 11 and the switching circuit 16 and the charging voltage Vc is boosted by this booster circuit and output to the switching circuit 16. On the contrary, when the charging voltage Vc of the capacitor 11 is too high as compared with the operating voltage Vop of the driving power supply 13, for example, a known step-down having a switching element, an inductor (or a step-down transformer) and a rectifying smoothing circuit. It is also possible to adopt a configuration in which the circuit is arranged between the capacitor 11 and the switching circuit 16 and the charging voltage Vc is stepped down by this step-down circuit and output to the switching circuit 16.

1 Impedance measuring device
2 1st connection terminal
3 2nd connection terminal
4 Current supply part 11 Capacitor 12 SEPP circuit 13 Drive power supply 16 Switching circuit 17 Main power supply 18 Control circuit 21, 22 Transistor 23 Input terminal 24 Output terminal 25 High potential side terminal 26 Low potential side terminal 51 Battery 52 Anode 53 Cathode
I Measured alternating current Vbat Battery voltage Vsp Supply voltage
Z internal impedance

Claims (2)

The first connection terminal to which the anode of the battery to be measured is connected, the second connection terminal to which the cathode of the battery is connected, the capacitor with one end connected to the second connection terminal, and the low potential side terminal are other than the capacitor. SEPP that is connected to the end and operates at the supply voltage supplied to the high potential side terminal to generate a measured AC current based on the AC signal input to the input terminal and output it from the output terminal to the first connection terminal. The circuit, a current supply unit having a drive power supply, a main power supply, and a control circuit that generates the supply voltage and supplies the supply voltage to the high potential side terminal, and is output to the battery via the first connection terminal. An impedance measuring device that measures the internal impedance of the battery based on the measured alternating current and the voltage between the first connection terminal and the second connection terminal.
The current supply unit has a switching circuit capable of outputting any one of the charging voltage of the capacitor and the DC power supply voltage output from the main power supply as the operating voltage of the driving power supply.
When the charging voltage is equal to or higher than the first reference voltage within the operating voltage range of the driving power supply, the control circuit causes the switching circuit to output the charging voltage as the operating voltage, and the charging voltage is the first. An impedance measuring device that executes a voltage switching process for outputting the DC power supply voltage as the operating voltage to the switching circuit when the voltage is less than one reference voltage. In the SEPP circuit, an NPN transistor whose collector terminal is connected to the high potential side terminal and whose emitter terminal is connected to the output terminal, and an NPN transistor whose emitter terminal is connected to the emitter terminal of the NPN transistor and which is a collector terminal. Has a PNP type transistor connected to the low potential side terminal.
The control circuit is a voltage control that controls the supply voltage of the drive power supply so that the collector-emitter voltage is maintained at a predetermined voltage while detecting the collector-emitter voltage of the NPN transistor. The impedance measuring device according to claim 1, wherein the processing is performed.

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