JP2019060719A - Inspection device - Google Patents

Abstract

To provide an inspection device with which it is possible to measure the internal resistance of an electric dual-layer capacitor with high accuracy while securing safety by output cutoff using an output relay.SOLUTION: Provided is an inspection device for performing constant-current charging and constant-current discharging and measuring the internal resistance of an electric dual-layer capacitor, comprising: an output terminal 12 to which the electric dual-layer capacitor is connected via a pair of wiring cables; a remote detection terminal to which the electric dual-layer capacitor is connected to a pair of wiring cables; a power supply circuit SRR for outputting a current to the electric dual-layer capacitor via the output terminal 12; a pair of output relays RY1, RY2 for cutting off a positive wiring and a negative wiring connecting the power supply circuit SRR and the output terminal 12 in conjunction; an element voltage detection unit for measuring the element voltage of the electric dual-layer capacitor via the remote detection terminal; and a capacitive element C1, connected in parallel to the output relay RY2 for negative wiring, for suppressing common-mode noise in the remote detection terminal.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an inspection apparatus, and more particularly, to an improvement of an inspection apparatus capable of measuring the internal resistance of an electric double layer capacitor with high accuracy.

  An electric double layer capacitor (EDLC) has a high output density and is known as a long-life storage device capable of charging and discharging a large current, and is used, for example, as a battery for an automobile. A battery using an electric double layer capacitor may be configured by connecting a plurality of electric double layer capacitors in parallel to increase the capacity. If an electric double layer capacitor having a large internal resistance is mixed in such a battery, a problem arises that the current is concentrated on the electric double layer capacitor having a small internal resistance. Therefore, it is necessary to make the internal resistances of the electric double layer capacitors connected in parallel substantially the same, and it is necessary to accurately measure the internal resistances of the electric double layer capacitors and to sort the electric double layer capacitors in advance. is there. For this reason, at the time of manufacturing the electric double layer capacitor, a characteristic test is performed to measure the internal resistance.

  FIG. 14 is a diagram showing an equivalent circuit of the electric double layer capacitor. The equivalent circuit of the electric double layer capacitor is constituted of a capacitive element C, a parallel internal resistance Rp and a series internal resistance Rs. The parallel internal resistance Rp is included in the capacitive element C, equivalently an internal resistance connected in parallel to the capacitive element C, and is obtained by measuring the leakage current of the capacitive element C in a constant voltage state . On the other hand, the series internal resistance Rs is an internal resistance connected in series to the capacitive element C. For example, constant current charge, constant voltage charge, constant current discharge are sequentially performed to switch from constant voltage charge to constant current discharge. It is determined by measuring the voltage drop at The internal resistance in this specification refers to the series internal resistance Rs unless otherwise specified.

  The measurement of the internal resistance is performed using a test apparatus incorporating a current control power supply. Since this built-in power supply is a power supply capable of outputting a large current of, for example, 20 A, an output relay is provided between the built-in power supply and the output terminal, and blocking the output except when measuring internal resistance. Desirable from Moreover, when measuring internal resistance based on the voltage change at the time of stopping charging and discharging, it is desirable to provide an output relay between the built-in power supply and the output terminal and completely shut off the current input and output during charging and discharging stop .

  However, in such a testing device, when the output relay shuts off the output, the electric double layer capacitor is electrically floated with respect to the testing device. In this state, when the device voltage of the electric double layer capacitor is detected, the device voltage can not be measured with high accuracy under the influence of common mode noise. For this reason, there existed a problem that the measurement precision of insulation internal resistance of an electric double layer capacitor fell.

JP 2015-45553

  The present invention has been made in view of the above-mentioned circumstances, and an inspection apparatus capable of measuring the internal resistance of an electric double layer capacitor with high accuracy while securing safety by output interruption using an output relay. Intended to be provided.

  The inspection apparatus according to the first aspect of the present invention is an inspection apparatus that performs constant current charging or constant current discharge to measure the internal resistance of the electric double layer capacitor, and the electric double layer capacitor is a pair of first wires. An output terminal connected thereto, a remote detection terminal to which the electric double layer capacitor is connected via a pair of second wires, and a power supply circuit outputting a current to the electric double layer capacitor through the output terminal A pair of output relays that interlock and cut off the positive electrode wiring and the negative electrode wiring that connect the power supply circuit and the output terminal, and an element voltage detection that measures an element voltage of the electric double layer capacitor via the remote detection terminal And an impedance element connected in parallel to the output relay for the negative electrode wiring and suppressing common mode noise in the remote detection terminal.

  In the inspection apparatus according to the second aspect of the present invention, in addition to the above configuration, a capacitive element is used as the impedance element.

  By adopting such a configuration, it is possible to cut off both the positive electrode wire and the negative electrode wire connecting the power supply circuit and the output terminal by the pair of interlocked output relays. Therefore, the safety of the inspection apparatus can be improved.

  Further, even if the pair of output relays cut off the positive electrode wiring and the negative electrode side wiring by connecting the capacitive element in parallel to the output relay for the negative electrode wiring, the negative electrode wiring is high frequency through the capacitive element. It is possible to maintain the connected state. That is, even after the output relay is shut off, the electric double layer capacitor can be suppressed from being in a floating state with respect to the detection device in the high frequency region. Therefore, even when the input impedance of the remote detection terminal is high and the output terminal is blocked by the output relay, generation of common mode noise in the element voltage can be suppressed, so the electric double layer The insulation internal resistance of the capacitor can be measured with high accuracy.

  In addition to the above configuration, the inspection apparatus according to the third aspect of the present invention is configured such that the input impedance of the remote detection terminal is higher than the input impedance of the output terminal.

  By adopting such a configuration, the device voltage of the electric double layer capacitor can be measured with high accuracy, and the insulation internal resistance of the electric double layer capacitor can be determined accurately.

  In the inspection apparatus according to the fourth aspect of the present invention, in addition to the above configuration, the element voltage detection unit includes an instrumentation amplifier that measures a voltage between the remote detection terminals.

  By adopting such a configuration, the influence of common mode noise can be suppressed. Therefore, the device voltage of the electric double layer capacitor can be measured with high accuracy, and the insulation internal resistance of the electric double layer capacitor can be accurately obtained.

  According to the present invention, it is possible to provide an inspection apparatus which measures the internal resistance of the electric double layer capacitor with high accuracy while securing safety by the output interruption using the output relay.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed an example of the inspection system containing the inspection apparatus 1 by Embodiment 1 of this invention. It is a figure showing an example of a measuring method of internal resistance of electric double layer capacitor. It is the figure which showed one structural example of the test | inspection apparatus 1 of FIG. It is the figure which showed an example of the detailed structure of the main circuit unit 114 of FIG. It is the figure which showed an example of the detailed structure of the current feedback circuit 2 of FIG. It is the figure which showed an example of the detailed structure of control unit 115 of FIG. 5 is a flowchart showing an example of a measurement sequence of the internal resistance by the inspection device 1; It is the flowchart which showed an example of detailed operation | movement of the constant current charge process (step S1) of FIG. It is the flowchart which showed an example of the detailed operation | movement of the charge stop process (step S2) of FIG. It is the flowchart which showed an example of the detailed operation | movement of the constant voltage charge process (step S3) of FIG. It is the flowchart which showed an example of the detailed operation | movement of the constant current discharge process (step S4) of FIG. It is the flowchart which showed an example of the detailed operation | movement of the discharge rest process (step S5) of FIG. FIG. 10 is a view showing the main part of the inspection apparatus 1 according to the second embodiment of the present invention, in which another configuration example of the control unit 115 is shown. It is a figure showing an equivalent circuit of an electric double layer capacitor.

Embodiment 1
<Overview of inspection system>
FIG. 1 is a diagram showing an example of an inspection system including an inspection apparatus 1 according to a first embodiment of the present invention. The inspection apparatus 1 is connected to one electric double layer capacitor 100 via two wiring cables 101 and 102. Further, a user terminal 103 is connected to the inspection apparatus 1. This inspection system assumes, for example, an electric double layer capacitor 100 having a capacitance of 3600 F and a maximum current of 20 A as an inspection object.

  The inspection apparatus 1 is an apparatus for measuring the internal resistance of the electric double layer capacitor 100, and is used, for example, in an inspection step in the manufacturing process of the electric double layer capacitor 100. The measurement of the internal resistance is performed by charging and discharging the electric double layer capacitor 100 and measuring the amount of change in the element voltage (voltage between terminals) of the electric double layer capacitor 100 at the start or end of the charge and discharge. The inspection apparatus 1 includes a power supply terminal 11, an output terminal 12, a remote detection terminal 13, and a communication terminal 14.

  The power supply terminal 11 is a terminal connected to an external power supply (not shown), and is supplied with, for example, 200 V AC. The power of the external power supply is DC converted in the inspection device 1 and output from the output terminal 12.

  The output terminal 12 is composed of a pair of terminals that supply or sink current to the electric double layer capacitor 100 to charge and discharge the electric double layer capacitor 100. Both terminals of the electric double layer capacitor 100 are respectively connected to the output terminal 12 via a pair of wiring cables 101.

  The remote detection terminals 13 are a pair of terminals for measuring the element voltage of the electric double layer capacitor 100 with high accuracy using the four-terminal method. Both terminals of the electric double layer capacitor 100 are respectively connected to the remote detection terminal 13 via a pair of wiring cables 102. Since the remote detection terminal 13 has an input impedance sufficiently higher than that of the output terminal 12, no current flows in the wiring cable 102, and the electric double layer is not affected by the voltage drop of the wiring cable 102. The element voltage of the capacitor 100 can be measured accurately. In order to measure the element voltage of the electric double layer capacitor 100 more accurately, it is desirable that the wiring cable 102 be directly connected to the terminal of the electric double layer capacitor 100.

  The communication terminal 14 is a terminal to which the user terminal 103 is connected. For example, a PC is connected to the communication terminal 14 as the user terminal 103. The user can perform various settings of the inspection apparatus 1 by operating the user terminal 103. In addition, the inspection apparatus 1 can be instructed to start measurement, and the measurement result can be acquired from the inspection apparatus 1.

<Method of measuring internal resistance>
FIG. 2 is a diagram showing an example of a method of measuring the internal resistance of electric double layer capacitor 100, and (a) in the figure shows the time change of the current supplied to electric double layer capacitor 100, In (b), the time change of the device voltage of the electric double layer capacitor 100 is shown. In this figure, three different methods of measuring the internal resistance are shown. In the inspection step of the electric double layer capacitor 100, all of these measurement methods may be performed, and inspection may be performed based on three measurement results, or only one or two arbitrary measurement methods are performed, or The inspection may be performed based on two or more measurement results.

  First, constant current charging of the electric double layer capacitor 100 is performed (time t0 to t1). Supply of predetermined charging current Ic to electric double layer capacitor 100 is started at time t0, and thereafter, supply of constant charging current Ic is continued until element voltage reaches predetermined charging target voltage Vc. Ru. In the figure, constant current charging of the electric double layer capacitor 100 is performed until time t1 when the element voltage reaches the charging target voltage Vc.

  Next, charging of the electric double layer capacitor 100 is temporarily stopped (time t1 to t2). The charging suspension is in a state where no input / output of current from the inspection apparatus 1 is performed to the electric double layer capacitor 100, and is continued until a predetermined suspension time T1 (for example, 1 second) elapses from time t1. . In the figure, charging / discharging of the electric double layer capacitor 100 is stopped until time t2. The element voltage drops from Vt1 to Vn1 due to this charging suspension.

  While constant current charging causes a voltage drop to occur in the internal resistance of electric double layer capacitor 100 due to the inflow of charging current Ic, this voltage drop does not occur during charging suspension, and the device is caused by the suspension of constant current charging The voltage drops. Therefore, assuming that the device voltages measured at times t1 and t2 are Vt1 and Vt2, the variation dV1 (= Vt1-Vt2) of the device voltage due to the suspension of constant current charging is the voltage drop of the internal resistance at the time of constant current charging The internal resistance can be obtained by dV1 / Ic.

  Next, constant voltage charging of the electric double layer capacitor 100 is performed (time t2 to t3). For the electric double layer capacitor 100 during charging suspension, constant voltage charging of the charging target voltage Vc is started at time t2, and then constant voltage charging continues until a predetermined charging time T2 (for example, 20 minutes) elapses. Be done. In the figure, constant voltage charging of the electric double layer capacitor 100 is performed until time t3. During the constant voltage charging, the charging current decreases with time, and the charging current is substantially zero by time t3 when the constant voltage charging ends. The charge time T2 is predetermined as a sufficiently long time that the charge current can be made substantially zero. The termination condition of the constant voltage charging may be defined by the detection current Id instead of the charging time T2.

  Next, constant current discharge of electric double layer capacitor 100 is performed (time t3 to t4). With respect to electric double layer capacitor 100 during constant voltage charging, extraction of discharge current Ie predetermined at time t3 is started, and thereafter, a constant discharge current until element voltage reaches predetermined discharge termination voltage Ve The withdrawal of Ie continues. In the drawing, constant current discharge of the electric double layer capacitor 100 is performed until time t4 when the element voltage reaches the discharge termination voltage Ve. The device voltage decreases from Vc to Vr due to the start of the discharge.

  Near the end of constant-voltage charging, no charging current flows, and no voltage drop occurs in the internal resistance, while discharge current Ie is drawn during constant-current discharge to the internal resistance of electric double layer capacitor 100. A voltage drop occurs. This voltage drop is a voltage in the opposite direction to that during the above-described pause (time t1 to t2), and the device voltage decreases due to the start of the constant current discharge. In other words, assuming that the device voltage measured at time t3 is Vt3 (Vc Vc), the variation dV2 (= Vt3-Vr) of the device voltage change due to the start of constant current discharge is the voltage drop of the internal resistance at the time of constant current discharge. It corresponds to a minute. Therefore, if the change amount dV2 of the element voltage is obtained, the internal resistance can be obtained by dV2 / Ie.

  Here, although the change amount dV2 of the element voltage at the start of the discharge can not be measured accurately, the change amount dV2 can be determined with higher accuracy by linear approximation of the voltage characteristic during the discharge. During constant current discharge, the device voltage decreases linearly with time. Therefore, the device voltages at two points P1 and P2 at different times during discharge are measured, the voltage characteristics during discharge are linearly approximated, and a voltage value Vr at the intersection of the approximate straight line and time t3 is determined. If the difference from the device voltage Vt3 at t3 is determined, the variation dV2 of the device voltage due to the start of the discharge can be obtained with high accuracy.

  Next, the discharge of the electric double layer capacitor 100 is stopped (time t4 to t5). The pause of discharge is a state in which no input / output of current from the inspection apparatus 1 is performed to / from the electric double layer capacitor 100 as in the pause of charge, and a pause time T3 (for example, 1 second) predetermined from time t4 It will continue until it passes. In the figure, charging / discharging of the electric double layer capacitor 100 is stopped until time t5. The element voltage rises from Ve to Vt5 due to this discharge pause.

  During constant current discharge, a voltage drop is generated in the internal resistance of electric double layer capacitor 100 due to the discharge of discharge current Ie. However, this voltage drop does not occur during discharge suspension, and the device is stopped by the suspension of constant current discharge. The voltage rises. Therefore, assuming that the device voltages measured at time t4 and t5 are Vt4 (≒ Ve) and Vt5, the variation dV3 (= Vt5-Vt4) of the device voltage due to the suspension of constant current discharge is This corresponds to the voltage drop of the resistor, and the internal resistance can be determined by dV3 / Ie.

  When it is going to measure internal resistance with high accuracy using such a measurement method, charge current Ic, discharge current Ie, and device voltage during constant voltage charge do not contain ripple and are stable with high accuracy There is a need. In addition, it is necessary for the charge current Ic and the discharge current Ie to have high response characteristics that quickly rise at the start of charge and discharge. Furthermore, the device voltage needs to be able to be measured with high accuracy. In particular, it is required that the device voltage can be measured with high accuracy even during charging / discharging pauses. The inspection apparatus 1 according to the present embodiment is an apparatus that satisfies such conditions and can measure the internal resistance with high accuracy, and the detailed configuration thereof will be further described.

<Schematic Configuration of Inspection Device 1>
FIG. 3 is a view showing one configuration example of the inspection apparatus 1 of FIG. The inspection apparatus 1 is configured by a plurality of power supply circuits 111 to 113 configured by a switching regulator (SWR), a main circuit unit 114 including a series regulator (SRR), and a control unit 115.

(1) Power supply circuits 111 to 113
The power supply circuits 111 to 113 are all switching regulators that convert external power and output DC voltages Vs1 to Vs3. The first power supply circuit 111 is a variable power supply that outputs the voltage Vs1 to the main circuit unit 114. The output voltage Vs1 is designated by a voltage command value Cv1 from the control unit 115. For example, the first power supply circuit 111 can supply 0 to 7.5 V as a power supply for charging operation.

  Similarly, the second power supply circuit 112 is also a variable power supply that outputs the voltage Vs2 to the main circuit unit 114. The output voltage Vs2 is designated by a voltage command value Cv2 from the control unit 115. For example, the second power supply circuit 112 can supply −3.3 V to 0 V as a power supply for discharge operation.

  The third power supply circuit 113 is a fixed power supply that supplies the control unit 115 with the voltage Vs3. For example, 24 V can be supplied as the output voltage Vs3.

(2) Main circuit unit 114
The main circuit unit 114 is a circuit board that constitutes the main circuit, and includes a series regulator that converts the output voltages Vs1 and Vs2 from the first and second power supply circuits 111 and 112 and outputs the voltage via the output terminal 12 , Charge and discharge of the electric double layer capacitor 100 are controlled.

(3) Control unit 115
The control unit 115 is a circuit board that controls the main circuit unit 114, incorporates a microprocessor, and is connected to the remote detection terminal 13 and the communication terminal 14. Control unit 115 generates voltage command values Cv1 and Cv2, and controls output voltages Vs1 and Vs2 of power supply circuits 111 and 112. In addition, it generates a current command value Iref and controls the output of the main circuit unit 114.

  Furthermore, the control unit 115 can detect the element voltage Vrm through the remote detection terminal 13, and the detected element voltage Vrm is used for charge / discharge control, and the internal resistance of the electric double layer capacitor 100. It is also used for measurement. Also, the control signal from the user terminal 103 is received through the communication terminal 14, and the measurement result is output to the user terminal 103.

<Detailed Configuration of Main Circuit Unit 114>
FIG. 4 is a diagram showing an example of a detailed configuration of the main circuit unit 114 of FIG. The main circuit unit 114 includes a series regulator SRR configured by the transistors TR1 to TR4. Note that elements shown as rectangles in the figure and not particularly mentioned are resistors.

(1) Push-pull circuit PP1
The push-pull circuit PP1 is a complementary emitter follower circuit configured of a pair of transistors TR1 and TR2. The common base terminal of the transistors TR1 and TR2 is an input terminal of the push-pull circuit PP1, and the common emitter terminal of the transistors TR1 and TR2 is an output terminal of the push-pull circuit PP1. The output voltage Vs1 of the first power supply circuit 111 is applied to the collector terminal of the transistor TR1, and the output voltage Vs2 of the second power supply circuit 112 is applied to the collector terminal of the transistor TR2. A charge current is supplied to electric double layer capacitor 100, and transistor TR2 draws a discharge current from electric double layer capacitor 100 during discharge.

The transistor TR1 is an NPN bipolar transistor constituting an emitter follower circuit, and a collector current obtained by amplifying the base current by the current amplification factor _hEF flows, and this collector current becomes a charging current of the electric double layer capacitor 100.

The transistor TR2 is a PNP bipolar transistor constituting an emitter follower circuit, and a collector current obtained by amplifying the base current by the current amplification factor _hEF flows, and this collector current becomes a discharge current of the electric double layer capacitor 100.

(2) Push-pull circuit PP2
The push-pull circuit PP2 is also a complementary emitter follower circuit composed of a pair of transistors TR3 and TR4, and the common emitter terminal of the transistors TR3 and TR4 is connected to the common base terminal of the transistors TR1 and TR2. By connecting two stages of push-pull circuits PP1 and PP2, transistors TR1 and TR3 are connected in Darlington connection, and transistors TR2 and TR4 are also connected in Darlington connection, and the current amplification factor h _EF is increased in both charging and discharging. It can be done. By adopting such a configuration, even the transistors TR1 and TR2 that output a large current can be driven by the operational amplifier OP1.

  The transistors TR <b> 1 to TR <b> 4 are all elements for performing current amplification, and do not perform the on / off operation like the transistors constituting the switching regulator. For this reason, a highly stable output without ripples can be obtained. In addition, since no smoothing process using a capacitive element is necessary, good response can be ensured. Therefore, measurement of the internal resistance of the electric double layer capacitor 100 can be performed with high accuracy.

(3) Output terminal 12
The positive terminal of the output terminal 12 is connected to the output terminal of the push-pull circuit PP1 via the shunt resistor SH and the output relay RY1. The negative terminal of the output terminal 12 is connected to the ground of the power supply circuits 111 and 112 via the output relay RY2.

(4) Shunt resistor SH
The shunt resistor SH is a resistive element for detecting an output current, and is provided closer to the push-pull circuit PP1 than the output relay RY1. The voltage across terminals of the shunt resistor SH is input to the current feedback circuit 2, and the detection current Id is obtained based on the voltage.

(5) Output relays RY1, RY2
The output relays RY1 and RY2 are switching elements provided between the series regulator SRR and the output terminal 12 and capable of interrupting a pair of wires connecting them. The output relays RY1 and RY2 operate in conjunction with each other based on the relay control signal Cry from the control unit 115, and both become closed when the electric double layer capacitor 100 is charged and discharged, and the electric double layer capacitor 100 is a push-pull circuit While being connected to PP1, the other is in an open state, and the electric double layer capacitor 100 is disconnected from the push-pull circuit PP1. That is, the output relays RY1 and RY2 are opened when the current command value Iref is zero, and shuts off the output of the series regulator SRR. By providing such output relays RY1 and RY2, it is possible to completely shut off the current input / output during charging / discharging suspension, and to measure the internal resistance with high accuracy. In addition, it is possible to prevent careless current output at the time of standby and to improve safety.

  A capacitive element C1 is connected in parallel to the output relay RY2 on the negative electrode side, and the electric double layer capacitor 100 and the ground of the inspection apparatus 1 are always connected at high frequency via the capacitive element C1. Therefore, when the output relay RY2 is in the open state, both terminals of the electric double layer capacitor 100 are prevented from floating with respect to the inspection apparatus 1. Therefore, it is possible to prevent the measurement accuracy of element voltage Vrm during charging / discharging pauses in which relays RY1 and RY2 are in the open state from being reduced by the influence of common mode (common mode voltage) noise in a high frequency region. .

(6) Current feedback circuit 2
The current feedback circuit 2 is a circuit that performs feedback control with the series regulator SRR as a control target, determines the detected current Id based on the output of the shunt resistor SH, and matches the detected current Id with the current command value Iref. The operation amount Ui is obtained. The detected current Id is an output of the control target, and the current command value Iref is a target value of the control target, and is given from the control unit 115. The operation amount Ui is input to the operational amplifier OP1 via the resistor R2. The detailed configuration of the current feedback circuit 2 will be described later.

(7) Output voltage detection unit 3
The output voltage detection unit 3 measures the voltage between the output terminals 12 on the side of the output terminals 12 relative to the output relays RY1 and RY2, and outputs the voltage as a detection voltage Vd. The detection voltage Vd is input to the operational amplifier OP1 via the resistor R1.

(8) Output control circuit 4
The output control circuit 4 is a control circuit that controls the output voltage of the series regulator SRR based on the detection voltage Vd and the operation amount Ui, and is configured of an operational amplifier OP1 and resistors R1 to R3.

  The operational amplifier OP1 is an amplification circuit that provides an input voltage to the push-pull circuit PP2 of the preceding stage, and is an inverting amplifier that feeds back the output voltage of the push-pull circuit PP1 of the subsequent stage to the inverting input terminal via the resistor R3. An inverted signal of the detection voltage Vd is input to the inverting input terminal of the operational amplifier OP1 through the resistor R1, and an inverted signal of the operation amount Ui generated by the current feedback circuit 2 is connected through the resistor R2.

  In this circuit, the output voltage of the series regulator SRR is (Vd / R1 + Ui / R2) × R3. That is, the output voltage of the series regulator SRR is represented as a weighted sum (linear sum) of the detection voltage Vd and the operation amount Ui. For example, if the resistors R1 to R3 have the same value, the output voltage of the series regulator SRR is the sum of the detection voltage Vd and the operation amount Ui.

  In the output control circuit 4, the detection voltage Vd is added to the operation amount Ui, and feedback control of the output current using the operation amount Ui and feedforward control of the output voltage using the detection voltage Vd are simultaneously performed. When controlling the output voltage by feeding back the manipulated variable Ui obtained from the detected current Id, the detected voltage Vd is added to the manipulated variable Ui to offset the manipulated variable Ui of feedback control, and the center of the change range is determined. It can be matched to the current output voltage. For this reason, feedback control can be performed more effectively, and responsiveness can be improved.

  Further, by adding the detection voltage Vd to the operation amount Ui, it is possible to make the voltages at both ends of the open output relay RY1 coincide with each other. As described later, when the output relay RY1 is in the open state, the current feedback circuit 2 is invalidated, and zero is output as the operation amount Ui. Therefore, when the detection voltage Vd is not used, a potential difference corresponding to the element voltage Vrm is generated at both ends of the open output relay RY1. In this state, if the output relay RY1 is turned on, a rush current flows due to the potential difference. On the other hand, if the output voltage is controlled using a value obtained by adding the detection voltage Vd to the operation amount Ui, the voltages at both ends of the open output relay RY1 can be made to coincide. As a result, it is possible to prevent the inrush current from flowing when the output relay RY1 is on, and to improve the responsiveness of the current output immediately after the output relay RY1 is on.

<Current feedback circuit 2>
FIG. 5 is a diagram showing an example of a detailed configuration of the current feedback circuit 2 of FIG. The current feedback circuit 2 obtains the detected current Id from the voltage across the terminals of the shunt resistor SH, outputs the detected current Id, and obtains the manipulated variable Ui of PI control with the current command value Iref as the target value. The illustrated current feedback circuit 2 includes a differential amplifier circuit A1, an inverting amplifier circuit A2, and a PI control circuit A3.

(1) Differential amplifier circuit A1
The differential amplifier circuit A1 is a current detection unit including the operational amplifier OP2 and a resistor element, and amplifies the voltage between the terminals of the shunt resistor SH to obtain a detection current Id. The detection current Id is output to the inverting amplification circuit A2 and is also output to the control unit 115.

(2) Inverting amplification circuit A2
The inverting amplification circuit A2 includes an operational amplifier OP3 and a resistance element, generates an inverted signal obtained by inverting the sign of the detection current Id, and inputs the inverted signal to the PI control circuit A3.

(3) PI control circuit A3
The PI control circuit A3 is a PI arithmetic circuit including an operational amplifier OP4, resistance elements R4 to R6, and a capacitance element C2, and obtains an operation amount Ui of PI control based on the difference between the detection current Id and the current command value Iref. . An inversion signal of the detection current Id is input to the inverting input terminal of the operational amplifier OP4 via the resistor R4, and a current command value Iref is input via the resistor R5. That is, the difference between the detected current Id and the current command value Iref is input to the operational amplifier OP4.

  A feedback circuit consisting of a series circuit of a resistor R6 and a capacitive element C2 is provided between the inverting input terminal and the output terminal of the operational amplifier OP4, and the operational amplifier OP4 has a proportional value (P component) to the input value and an integral value (I Output the sum of the components). With such a configuration, PI calculation is performed on the detected current Id, and an inverted signal of the operation amount Ui used in PI control is generated.

  Furthermore, the invalidation switch AS is connected in parallel to the feedback circuit of the operational amplifier OP4. The disabling switch AS is a switch that disables PI control by shorting between the inverting input terminal and the output terminal of the operational amplifier OP4, and for example, an analog switch is used. The disabling switch AS operates based on the disabling signal Cas from the control unit 115. At the time of PI control, the invalidation signal Cas becomes inactive and the invalidation switch AS is opened, while at idle when PI control is not performed, the invalidation signal Cas becomes active and the invalidation switch AS is closed. Become. If the disabling switch AS is closed, the manipulated variable Ui becomes zero regardless of the input value to the operational amplifier OP4, and PI control is disabled.

  When the output relay RY1 is in the open state and the output relay RY1 blocks the output, the manipulated variable Ui of PI control is not reflected in the detected current Id. As a result, feedback control of the output current does not function properly, and the output voltage of the series regulator SRR is not determined.

  For example, even if the current command value Iref is made zero, the detected current Id does not completely match the current command value Iref in analog control, and an error always occurs. When the error is integrated by the PI control circuit A3, an unintended manipulated variable Ui is output. At this time, since the output relay RY1 is in the open state, the manipulated variable Ui is not reflected in the detected current Id, and the manipulated variable Ui monotonously increases or decreases with the passage of time, and swings off to the maximum value or the minimum value. It will

  As a result, the transistors TR1 to TR4 are destroyed due to thermal runaway during idling, or a large potential difference is generated between both terminals of the output relay RY1, and the rush current is applied to the electric double layer capacitor 100 when the output relays RY1 and RY2 are subsequently turned on. It may flow. In order to prevent the occurrence of such a problem, at the time of idling, the operation amount Ui is forcibly fixed to zero by the invalidation switch AS.

<Control unit 115>
FIG. 6 is a diagram showing an example of a detailed configuration of the control unit 115 of FIG. The control unit 115 is a circuit unit that controls the power supply circuits 111 to 113 and the main circuit unit 114, and includes a wiring characteristic storage unit 40, an element voltage detection unit 41, a voltage control unit 42, and a sequence control unit 43.

(1) Wiring characteristic storage unit 40
The wiring characteristic storage unit 40 holds the electrical characteristic of the wiring cable 101 connecting the output terminal 12 and the electric double layer capacitor 100 to each other. For example, the impedance of the wiring cable 101 is held in the wiring characteristic storage unit 40 as the wiring characteristic Cz. The wiring characteristics Cz are input in advance before the start of the inspection of the electric double layer capacitor 100 by the user operation on the user terminal 103 or the inspection apparatus 1.

(2) Device voltage detection unit 41
The element voltage detection unit 41 is a circuit connected to the remote detection terminal 13 to detect the element voltage Vrm of the electric double layer capacitor 100. By measuring the voltage of the remote detection terminal 13 instead of the voltage of the output terminal 12, it is possible to accurately detect the element voltage Vrm of the electric double layer capacitor 100 using the four-terminal method. Further, even when the output relays RY1 and RY2 are open, the element voltage Vrm can be detected.

  The element voltage detection unit 41 uses a circuit having a high input impedance and capable of accurately measuring the element voltage of the electric double layer capacitor 100, for example, a differential amplifier. In particular, it is desirable to use an instrumentation amplifier. Since the in-amp has a good common mode rejection ratio, the device voltage Vrm can be measured more accurately. However, even with the in-amp, it is difficult to sufficiently remove the influence of the common mode in the high frequency region. Therefore, the capacitance element C1 is further provided to suppress the mixing of the common mode in the high frequency region.

  The ground of the element voltage detection unit 41 is electrically connected to the ground of the main circuit unit 114. That is, the ground of the element voltage detection unit 41 is connected to the negative electrode of the electric double layer capacitor 100 via the output relay RY2 on the negative electrode side. However, when the output relays Ry1 and RY2 are in the open state, the electric double layer capacitor 100 is insulated from the ground of the element voltage detection unit 41 and floats with respect to the element voltage detection unit 41. If the device voltage Vrm is measured in this state, the measurement accuracy of the device voltage Vrm is reduced due to the influence of common mode noise.

  Therefore, the capacitive element C1 is connected in parallel to the output relay RY2 on the negative electrode side, and both ends of the open output relay RY2 are connected in a high frequency to suppress the occurrence of high frequency common mode noise. Therefore, even when the output relays RY1 and RY2 are in the open state, the device voltage detection unit 41 can measure the device voltage Vrm with high accuracy. As a result, the element voltage Vrm can be measured with high accuracy even during charging / discharging pauses.

(3) Voltage control unit 42
The voltage control unit 42 generates voltage command values Cv1 and Cv2 based on the wiring characteristics Cz and the element voltage Vrm, and controls the output voltages Vs1 and Vs2 of the power supply circuits 111 and 112. By this voltage control, the heat loss generated in the transistors Tr1 and Tr2 is reduced.

  The transistors TR1 and TR2 constituting the emitter follower circuit generate losses in accordance with the output current and the collector-emitter voltage Vce. Therefore, if the collector-emitter voltage Vce is reduced, the loss can be reduced while maintaining the output current. However, in order for the emitter follower circuit to operate normally, the condition is that the collector-emitter voltage Vce exceeds the collector-emitter saturation voltage Vce (sat) of the transistors TR1 and TR2.

  Therefore, it is desirable that the voltage command values Cv1 and Cv2 specify the smallest possible output voltages Vs1 and Vs2 in the range in which the transistors Tr1 and Tr2 satisfy Vce> Vce (sat).

上式において、右辺の第１項（Ｖｃｅ）は定数であるのに対し、第２項（Ｃｚ×Ｉｄ）及び第３項（Ｖｒｍ）は、いずれも充放電中に変化する値である。 Output voltage Vs1 of power supply circuit 111 is expressed by the following equation using collector-emitter voltage Vce of transistor TR1, voltage drop (Cz × Id) in wiring cable 101, and element voltage Vrm of electric double layer capacitor 100. be able to.

In the above equation, while the first term (Vce) on the right side is a constant, the second term (Cz × Id) and the third term (Vrm) are both values that change during charging and discharging.

  The voltage drop (Cz × Id) in the second term is a value proportional to the output current of the inspection apparatus 1. As shown in FIG. 2 (a), the current changes instantaneously at the start of charge and discharge. In the case of the inspection apparatus 1 according to the present embodiment, the rise time of the charge and discharge current is about 60 mS. It is difficult to make the voltage feedback control of the power supply circuit 111 follow such a short time change. Therefore, the voltage drop (Cz × Id) needs to be estimated in advance at the maximum value. That is, since the maximum value of the output current during the charging operation is the charging current Ic, it is necessary to estimate (Cz × Ic) as the value of the second term.

  The element voltage Vrm of the third term is a voltage between terminals of the electric double layer capacitor 100, and is a value which changes in accordance with the state of charge. However, as shown in FIG. 2B, the change in the device voltage Vrm during charging and discharging is extremely slow compared to the change in the voltage drop of the wiring cable 101. Therefore, as the Vrm of the third term, the detection value by the element voltage detection unit 41 can be used.

電源回路１１２の指令値Ｃｖ２についても、電流の向きが電圧指令値Ｃｖ１と逆になる点を除き同様であり、放電動作中における出力電流の最大値はＩｅであるから、電圧指令値Ｃｖ２も以下の式により求めることができる。

From the above, voltage command value Cv1 can be determined by the following equation.

The same applies to command value Cv2 of power supply circuit 112 except that the direction of the current is reverse to voltage command value Cv1, and the maximum value of the output current during the discharging operation is Ie. It can be obtained by the equation of

  In the formulas (2) and (3), Vce, Ic and Ie are constants, Cz is a value determined by the wiring cable 101, and Vrm is a value which changes during charge and discharge operation. Therefore, voltage control unit 42 determines voltage command values Cv1 and Cv2 using these equations. That is, voltage command values Cv1 and Cv2 are determined based on the wiring characteristic Cz specified by the user and the detected element voltage Vrm.

  The inspection apparatus 1 according to the present embodiment measures the element voltage Vrm by the four-terminal method to separately obtain the voltage drop of the wiring cable 101 and the element voltage Vrm of the electric double layer capacitor 100. Therefore, voltage control based on the element voltage Vrm can be performed. As described above, while the change of the former is difficult to follow by voltage control, the change of the latter is relatively easy to follow by voltage control. Voltage control based on the voltage Vrm can be realized, and heat loss can be reduced.

  In general, the saturation voltage Vce (sat) of the transistor is 0.7 V or less. Therefore, Vce in the first term of the above equations (2) and (3) may be estimated to be about 1 V in consideration of the margin.

(4) Sequence control unit 43
The sequence control unit 43 generates the current command value Iref, the relay control signal Cry and the invalidation signal Cas based on the detection current Id and the element voltage Vrm, and performs sequence control of internal resistance measurement.

<Measurement sequence>
Steps S1 to S5 in FIG. 7 are a flowchart showing an example of a measurement sequence of the internal resistance by the inspection apparatus 1, and the operation of the sequence control unit 43 in FIG. 6 is shown. This flowchart is executed by a measurement start instruction from the user terminal 103. The wiring characteristic Cz of the wiring cable 101 is designated from the user terminal 103 as preparation in advance. In addition, before the start of measurement, the invalidation switch AS is in the closed state, and the output relays RY1 and RY2 are in the open state.

  When a measurement start command is input, sequence control unit 43 performs constant current charge processing (step S1) for supplying charge current Ic, charge suspension processing for stopping constant current charge (step S2), determination by charge target voltage Vc The constant voltage charging process (step S3) for performing voltage charging, the constant current discharge process for extracting the discharge current Ie (step S4), and the discharge stop process for stopping the constant current discharge (step S5) are sequentially performed. The details of each of these processes will be described in order.

(1) Constant Current Charging Process Steps S101 to S104 in FIG. 8 are flowcharts showing an example of a detailed operation of the constant current charging process (step S1) in FIG. 7. When the measurement start command is input, the sequence control unit 43 changes the relay control signal Cry to an on signal. As a result, the output relays RY1 and RY2 are closed, enabling current output (step S101). Since both ends of the open output relay RY1 are held at the same potential by feedforward control of the detection voltage Vd, rush current does not flow in the electric double layer capacitor 100 by the on operation of the output relay RY1. Next, the sequence control unit 43 changes the invalidation signal Cas to be inactive. As a result, the invalidation switch AS is opened, and PI control is validated (step S102).

  Next, sequence control unit 43 changes current command value Iref to charging current Ic specified in advance. As a result, the charging current Ic is supplied from the transistor TR1 to the electric double layer capacitor 100, and constant current charging is started (step S103). The rise time of the output current at this time is shorter than when current control is performed by the switching power supply, and good response characteristics can be obtained.

  The sequence control unit 43 monitors the element voltage Vrm during constant current charging, and ends the constant current charging process if the element voltage Vrm reaches the charging target voltage Vc (step S104).

(2) Charging Pause Process Steps S201 to S205 in FIG. 9 are a flowchart showing an example of a detailed operation of the charge pause process (step S2) in FIG. When the constant current charging process (step S1) is completed, the sequence control unit 43 measures the detected current Id and the element voltage Vrm (Vt1) at that time (step 201), and then temporarily suspends charging. Charging suspension is performed by disabling PI control and turning off the output relays RY1 and RY2 (steps S202 and S203).

  The sequence control unit 43 first changes the invalidation signal Cas to active to inactivate the PI control (step S202). By disabling PI control during charging suspension, it is possible to prevent the runaway of control of the series regulator SRR during idling.

  Next, the sequence control unit 43 changes the relay control signal Cry to an off signal to open the output relays RY1 and RY2, and the charging by the inspection apparatus 1 is paused (step S203). By turning off the output relays RY1 and RY2 and disconnecting the electric double layer capacitor 100 from the series regulator SRR in the charging pause, it is possible to completely shut off the current input / output to the electric double layer capacitor 100 in the charging pause.

  Thereafter, when a predetermined pause time T1 (for example, one second) has elapsed (step S204), the sequence control unit 43 measures the element voltage Vrm (Vt2), and ends the charge pause process (step S205). When measuring the element voltage Vt2, the output relays RY1 and RY2 are in the open state, but both ends of the output relay RY2 on the negative electrode side are connected in a high frequency via the capacitive element C1. Thus, the element voltage Vt2 can be measured with high accuracy.

(3) Constant Voltage Charging Process Steps S301 to S304 in FIG. 10 are a flowchart showing an example of a detailed operation of the constant voltage charging process (step S3) in FIG. 7. When the charging suspension process (step S2) is completed, the sequence control unit 43 turns on the output relays RY1 and RY2, enables PI control, and starts constant voltage charging (steps S301 to S303).

  First, the sequence control unit 43 changes the relay control signal Cry to an on signal to close the output relays RY1 and RY2 and enable current output (step S301). Since both ends of the open output relay RY1 are held at the same potential by feed forward control of the detection voltage Vd during charging suspension, rush current flows in the electric double layer capacitor 100 by the on operation of the output relay RY1. There is no. Next, the sequence control unit 43 changes the invalidation signal Cas to be inactive, whereby the invalidation switch AS is opened, and PI control is enabled (step S302).

  Thereafter, constant voltage control is started (step S303). The constant voltage control is performed by the sequence control unit 43 determining the current command value Iref based on an error (Vc−Vrm) of the element voltage Vrm with respect to the charging target voltage Vc. Thereafter, when a predetermined charging time T2 (for example, 20 minutes) has elapsed, the constant voltage charging process is ended (step S304).

(4) Constant Current Discharge Process Steps S401 to S404 in FIG. 11 are flowcharts showing an example of a detailed operation of the constant current discharge process (step S4) in FIG. When the constant voltage charging process (step S3) is completed, the sequence control unit 43 measures the element voltage Vrm (Vt3) and then starts constant current charging (steps S401 and S402).

  Sequence control unit 43 changes current command value Iref to discharge current Ie designated in advance. As a result, discharge current Ie is drawn from electric double layer capacitor 100 to transistor TR2, and constant current discharge is started (step S402). The rise time of the input current at this time is shorter than in the case of performing current control by the switching power supply, and good response characteristics can be obtained.

  The sequence control unit 43 periodically repeats the measurement of the detection current Id and the device voltage Vrm during the constant current discharge, and terminates the processing of the constant current discharge when the device voltage Vrm reaches the discharge termination voltage Ve (step S404). ).

(5) Discharge Pause Processing Steps S501 to S505 in FIG. 12 are flowcharts showing an example of the detailed operation of the discharge pause processing (step S5) in FIG. When the constant current discharge process (step S4) is completed, the sequence control unit 43 measures the detection current Id and the element voltage Vrm (Vt4) at that time (step S501), and then stops the discharge.

  In order to stop the discharge, the sequence control unit 43 first changes the invalidation signal Cas to active to invalidate PI control (step S502). By disabling the PI control during the discharge pause, it is possible to prevent the runaway of the control of the series regulator SRR during idling.

  Next, the sequence control unit 43 changes the relay control signal Cry to an off signal, whereby the output relays RY1 and RY2 are opened, and the discharge by the inspection apparatus 1 is paused (step S503). By turning off the output relays RY1 and RY2 and disconnecting the electric double layer capacitor 100 from the series regulator SRR in the discharge pause, the current input / output to the electric double layer capacitor 100 can be completely cut off in the discharge pause.

  Thereafter, when a predetermined pause time T3 (for example, one second) has elapsed (step S504), the sequence control unit 43 measures the element voltage Vrm (Vt5), and ends the discharge pause process (step S505). When the element voltage Vt5 is measured, the output relays RY1 and RY2 are in the open state, but both ends of the output relay RY2 on the negative electrode side are connected in a high frequency via the capacitive element C1. Thus, the element voltage Vt5 can be measured with high accuracy.

Second Embodiment
In the first embodiment, an example of holding the wiring characteristic Cz specified by the user has been described. On the other hand, in the present embodiment, the inspection apparatus 1 which measures and holds the wiring characteristic Cz in advance will be described.

  FIG. 13 is a diagram showing the main part of the inspection apparatus 1 according to the second embodiment of the present invention, and shows another configuration example of the control unit 115. As shown in FIG. The control unit 115 of FIG. 13 differs from that of FIG. 6 (Embodiment 1) in that the control unit 115 includes a wiring characteristic detection unit 50 and a wiring characteristic determination unit 51. In the embodiment, only the difference from the first embodiment will be described, and the overlapping description will be omitted.

(1) Wiring characteristic detection unit 50
The wiring characteristic detection unit 50 obtains the wiring characteristic Cz based on the detection voltage Vd, the element voltage Vrm and the detection current Id. The wiring characteristic Cz can be obtained as the ratio of the current and the voltage drop at that time if the current flowing through the wiring cable 101 can be obtained. The voltage drop of the wiring cable 101 is given as the difference between the detection voltage Vd and the element voltage Vrm. That is, the wiring characteristic Cz can be expressed by the following equation using the detection voltage Vd, the element voltage Vrm and the detection current Id.

  The wiring characteristic detection unit 50 obtains the wiring characteristic Cz using the above equation (4). The detection of the wiring characteristic Cz is performed when a new wiring cable 101 is connected to the inspection apparatus 1, and the detected wiring characteristic Cz is stored in the wiring characteristic storage unit 40 and used for the subsequent internal resistance measurement. Be done.

  The wiring characteristic Cz is detected in a state where the electric double layer capacitor 100 is connected to the inspection apparatus 1 through the wiring cables 101 and 102, as in the measurement of the internal resistance. When a detection start command is input from the user terminal 103, a current is supplied from the inspection apparatus 1 to the electric double layer capacitor 100. This current is smaller than that at the time of internal resistance measurement, and flows for a short period of time as compared to the time of internal resistance measurement, and the detection voltage Vd, the element voltage Vrm and the detection current Id are measured.

  If the output time is short, even if control of voltage command values Cv1 and Cv2 based on wiring characteristics Cz is not performed, the influence on inspection apparatus 1 is small. Therefore, if the wiring characteristics Cz are measured and stored in the first short time after the start of the internal resistance measurement, and thereafter the stored wiring characteristics Cz are used, the wiring is performed before the start of the internal resistance measurement. There is no need to prepare in advance to measure the characteristic Cz. In addition, if the wiring characteristics are automatically measured each time the internal resistance measurement is started, the loss can be reduced even when the user changes the wiring or equipment.

(2) Wiring characteristic determination unit 51
The wiring characteristic determination unit 51 determines whether the wiring characteristic Cz detected by the wiring characteristic detection unit is an abnormal value, and performs alert output based on the determination result. The wiring characteristic determination unit 51 compares the wiring characteristic Cz with a predetermined threshold value. For example, when the wiring characteristic Cz exceeds the upper threshold Cmax, an alert is output. The alert output may be a signal output to the user terminal 103 or the like, or may be a display output or an audio output in the inspection apparatus 1.

  In addition, the wiring characteristic determination unit 51 may be given in advance the upper threshold Cmax and the lower threshold Cmin, compare the wiring characteristics Cz with the respective thresholds Cmax and Cmin, and may perform alert output based on the comparison results. For example, it may be determined whether or not the wiring characteristic Cz is within the normal range of Cmin or more and Cmax or less, and alert output may be performed when it is outside the range.

  According to the present embodiment, since there is no need for the user to specify the wiring characteristic Cz, it is not necessary to perform complicated setting work. In addition, proper internal resistance measurement can be performed using the accurate wiring characteristics Cz of the actual wiring cable 101. As a result, when the user designates an incorrect wiring characteristic Cz, an excessive current flows to cause thermal destruction of the inspection apparatus 1 or generation of a defect in which only an extremely small current flows and the internal resistance can not be measured. Can. Furthermore, when the wiring cable 101 having the inappropriate wiring characteristics Cz is connected to the inspection apparatus 1, an alert can be output to notify the user.

  In the embodiment, an example is described in which a smaller current is supplied at the time of detecting the wiring characteristics than at the time of measuring the internal resistance, but the present invention is not limited to such a case. For example, at the time of wiring characteristic detection, the same current as the current (especially maximum current) at the time of internal resistance measurement flows, voltage drop (Vd−Vrm) in wiring cable 101 at that time is determined, and this voltage drop is held as wiring characteristic Cz. It can also be used for voltage control.

  In the embodiment, the wiring characteristic determination unit 51 determines the wiring characteristics detected by the wiring characteristic detection unit 50, and the alert output is performed based on the determination result. It is not limited only to such a case. For example, the wiring characteristic determination unit 51 may make a determination on the wiring characteristic specified by the user, and may perform alert output based on the determination result.

Reference Signs List 1 inspection apparatus 2 current feedback circuit 3 voltage detection unit 4 output control unit 100 electric double layer capacitor 101, 102 wiring cable 103 user terminal 111 to 113 power supply circuit 114 main circuit unit 115 control unit 11 power supply terminal 12 output terminal 13 remote detection terminal 14 communication terminal 40 wiring characteristic storage unit 41 element voltage detection unit 42 voltage control unit 43 sequence control unit 50 wiring characteristic detection unit 51 wiring characteristic determination unit A1 differential amplifier circuit (current detection unit)
A2 Inverting amplification circuit A3 PI control circuit AS invalidation switch C, C1, C2 Capacitance element Cas invalidation signal Cry relay control signal Cv1, Cv2 voltage command value dV1 to dV3 voltage drop width Ic charging current Ie discharging current Id detecting current Iref current Command value OP1 to OP4 Operational amplifier PP1, PP2 Push-pull circuit R1 to R6 Resistance Rp Parallel internal resistance Rs Series internal resistance (internal resistance)
RY1 and RY2 Output relay SH Shunt resistor SRR Series regulator SWR Switching regulator TR1 to TR4 Transistor Ui Operating amount Vc Charge target voltage Ve Discharge termination voltage Vs1 to Vs3 Power supply voltage Vd Detection voltage Vrm, Vt2, Vt3, Vt5 Element voltage

Claims (4)

In a test apparatus for performing constant current charging or constant current discharging to measure the internal resistance of an electric double layer capacitor,
An output terminal to which the electric double layer capacitor is connected via a pair of first wires;
A remote detection terminal to which the electric double layer capacitor is connected via a pair of second wires;
A power supply circuit for outputting a current to the electric double layer capacitor via the output terminal;
A pair of output relays that interlock and cut off the positive electrode wiring and the negative electrode wiring that connect the power supply circuit and the output terminal;
An element voltage detection unit that measures an element voltage of the electric double layer capacitor via the remote detection terminal;
An inspection device comprising an impedance element connected in parallel to the output relay for the negative electrode wiring and suppressing common mode noise in the remote detection terminal.   The inspection apparatus according to claim 1, wherein the impedance element is a capacitive element.   The inspection apparatus according to claim 2, wherein an input impedance of the remote detection terminal is higher than an input impedance of the output terminal.   The inspection device according to claim 3, wherein the element voltage detection unit includes an instrumentation amplifier that measures a voltage between the remote detection terminals.

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