JP6957794B2 - Inspection equipment - Google Patents

Description

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

An electric double layer capacitor (EDLC) is known as a long-life power storage device having a high output density and capable of charging and discharging a large current, and is used as, for example, an automobile battery. A battery using an electric double layer capacitor may be configured by connecting a plurality of electric double layer capacitors in parallel in order to increase the capacity. If electric double layer capacitors having greatly different internal resistances coexist in such a battery, there arises a problem that the current concentrates on the electric double layer capacitors having a small internal resistance. For this reason, 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 resistance of the electric double layer capacitors and select the electric double layer capacitors in advance. be. Therefore, when manufacturing an electric double layer capacitor, a characteristic test for measuring the internal resistance is performed.

FIG. 14 is a diagram showing an equivalent circuit of an electric double layer capacitor. The equivalent circuit of an electric double layer capacitor is composed of a capacitance element C, a parallel internal resistance Rp, and a series internal resistance Rs. The parallel internal resistance Rp is an internal resistance contained inside the capacitance element C and is equivalently connected in parallel to the capacitance element C, and is obtained by measuring the leakage current of the capacitance 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 capacitance element C. For example, when constant current charging, constant voltage charging, and constant current discharging are performed in this order to switch from constant voltage charging to constant current discharging. It is obtained by measuring the voltage drop in. Unless otherwise specified, the internal resistance in the present specification refers to the series internal resistance Rs.

The measurement of internal resistance is performed using an inspection device having a built-in 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, it is a viewpoint of ensuring safety that an output relay is provided between the built-in power supply and the output terminal to shut off the output except when measuring the internal resistance. Is desirable from. When measuring the internal resistance based on the voltage change when charging / discharging is suspended, it is desirable to provide an output relay between the built-in power supply and the output terminal to completely cut off the current input / output during charging / discharging suspension. ..

However, if the output is cut off by the output relay, the output current is forcibly fixed to zero, so that an abnormality may occur in the current feedback control in the built-in power supply, and the control may run out of control. For example, when PI control of the output current is performed, if a steady error occurs in the measured value of the output current, the error is integrated with the passage of time and the manipulated variable increases. However, since the output current is fixed at zero and does not fluctuate, an abnormality in the manipulated variable is not reflected in the output current, and the manipulated variable continues to increase. As a result, the operation amount of PI control may be overwhelmed.

As a result, the built-in power supply may be destroyed. Further, if the manipulated variable is an abnormal value, a large potential difference is generated at both ends of the output relay. When an electric double layer capacitor is connected to an inspection device in such a state and the output relay is turned on to start internal resistance measurement, there is a problem that an inrush current flows through the electric double layer capacitor due to the potential difference between both ends of the output relay at that time. Occurs. Further, after the output relay is turned on, it takes time for the potential difference between both ends of the output relay to disappear, and if the measurement is started immediately after the output relay is turned on, the responsiveness of the current output is also affected.

JP-A-2015-45553

The present invention has been made in view of the above circumstances, and provides an inspection device that prevents abnormal occurrence of current control of a power supply circuit during output cutoff while ensuring safety by output cutoff using an output relay. The purpose is to do. Another object of the present invention is to provide an inspection device that suppresses the generation of inrush current when the output relay is turned on.

The inspection device according to the first aspect of the present invention is an inspection device that measures the internal resistance of the electric double layer capacitor by performing constant current charging or constant current discharging, and is connected to an output terminal to which the electric double layer capacitor is connected. A power supply circuit that outputs a current to the electric double layer capacitor via the output terminal, an output relay that cuts off the output of the power supply circuit between the power supply circuit and the output terminal, and an output current of the power supply circuit. A current detector that measures as a detection current, a current feedback circuit that obtains an operation amount to match the detection current with the current command value, and an output control circuit that controls the output of the power supply circuit based on the operation amount. The current feedback circuit is configured to output zero as the operation amount when the output relay is cut off, regardless of the operation amount obtained from the detection current.

With such a configuration, the current feedback circuit obtains the operation amount for matching the detected current with the current command value, and the output control circuit controls the output of the power supply circuit based on the operation amount. Feedback control can be performed. When the output relay is in the cutoff state, zero is output as the manipulated variable regardless of the manipulated variable obtained from the detected current. Therefore, in a state where the output current is fixed to zero and the manipulated variable is not reflected in the output current, it is possible to prevent an abnormal value from being output as the manipulated variable from the current feedback circuit.

In addition to the above configuration, the inspection device according to the second aspect of the present invention includes a PI calculation circuit in which the current feedback circuit performs PI calculation on the deviation of the detected current with respect to the current command value to obtain the operation amount. Then, when the output relay is in the cutoff state, the PI operation is invalidated, and zero is output as the operation amount.

By adopting such a configuration, when the output relay is in the cutoff state, the PI calculation is invalidated and zero is output as the operation amount. Therefore, it is possible to prevent the PI calculation from outputting an abnormal value in a state where the output current is fixed to zero and the manipulated variable is not reflected in the output current.

In the inspection device according to the third aspect of the present invention, in addition to the above configuration, the PI arithmetic circuit includes an operational amplifier, a series circuit of resistors and capacitive elements that feed back the output of the operational amplifier to the inverting input terminal, and the series circuit. When the current command value is zero, the output relay is cut off, the analog switch is short-circuited, and zero is output as the operational amplifier. It is composed.

In addition to the above configuration, the inspection device according to the fourth aspect of the present invention includes a voltage detection unit that measures the output voltage of the power supply circuit as a detection voltage, and the output control circuit is based on the detection voltage and the operation amount. Therefore, it is configured to control the output voltage of the power supply circuit.

With such a configuration, the output control circuit is configured to control the output voltage of the power supply circuit based on the detected voltage and the manipulated variable. Therefore, the feedback control of the output current and the feedforward control of the output voltage can be performed at the same time. Further, when the output relay is in the cutoff state, the operation amount becomes zero, the feedback control of the output current is invalidated, and the output voltage of the power supply circuit can be controlled by the feedforward control of the output voltage.

In addition to the above configuration, the inspection device according to the fifth aspect of the present invention is configured such that the voltage detection unit measures the output voltage of the power supply circuit on the output terminal side of the output relay.

With such a configuration, the output voltage of the power supply circuit is controlled by feedforward control of the output voltage on the output terminal side of the output relay. Therefore, when the output relay is in the cutoff state, the output voltage of the power supply circuit can be controlled so that the potentials at both ends of the output relay match, and it is possible to prevent an inrush current from flowing when the relay is turned on.

According to the present invention, it is possible to provide an inspection device that prevents abnormal occurrence of current control of a power supply circuit during output cutoff while ensuring safety by output cutoff using an output relay. Further, it is possible to provide an inspection device that suppresses the generation of inrush current when the output relay is turned on.

It is a figure which showed an example of the inspection system including the inspection apparatus 1 by Embodiment 1 of this invention. It is a figure which showed an example of the measuring method of the internal resistance of an electric double layer capacitor 100. It is a figure which showed one configuration example of the inspection apparatus 1 of FIG. It is a figure which showed an example of the detailed structure of the main circuit unit 114 of FIG. It is a figure which showed an example of the detailed structure of the current feedback circuit 2 of FIG. It is a figure which showed an example of the detailed structure of the control unit 115 of FIG. It is a flowchart which showed an example of the measurement sequence of the internal resistance by the inspection apparatus 1. It is a flowchart which showed an example of the detailed operation of the constant current charging process (step S1) of FIG. It is a flowchart which showed an example of the detailed operation of the charge suspension process (step S2) of FIG. It is a flowchart which showed an example of the detailed operation of the constant voltage charge processing (step S3) of FIG. It is a flowchart which showed an example of the detailed operation of the constant current discharge process (step S4) of FIG. It is a flowchart which showed an example of the detailed operation of the discharge suspension process (step S5) of FIG. It is a figure which showed the main part of the inspection apparatus 1 by Embodiment 2 of this invention, and has shown the other structural example of the control unit 115. It is a figure which showed the equivalent circuit of the electric double layer capacitor.

Embodiment 1.
<Overview of inspection system>
FIG. 1 is a diagram showing an example of an inspection system including the inspection device 1 according to the first embodiment of the present invention. The inspection device 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 device 1. This inspection system assumes, for example, an electric double layer capacitor 100 having a capacitance of 3600F and a maximum current of 20A as an inspection target.

The inspection device 1 is a device for measuring the internal resistance of the electric double layer capacitor 100, and is used, for example, in an inspection step during the manufacturing process of the electric double layer capacitor 100. The internal resistance is measured 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 charging and discharging. The inspection device 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 for example, AC200V is supplied. The electric power of the external power source is converted to direct current in the inspection device 1 and output from the output terminal 12.

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

The remote detection terminal 13 is a pair of terminals for measuring the element voltage of the electric double layer capacitor 100 with high accuracy by using the four-terminal method. Both terminals of the electric double layer capacitor 100 are connected to the remote detection terminal 13 via a pair of wiring cables 102, respectively. Since the remote detection terminal 13 has a sufficiently high input impedance as compared with the output terminal 12, no current flows through 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 is 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 a user terminal 103. The user can make various settings of the inspection device 1 by operating the user terminal 103. In addition, the inspection device 1 can be instructed to start measurement, and the measurement result can be obtained from the inspection device 1.

<Measurement method of internal resistance>
FIG. 2 is a diagram showing an example of a method for measuring the internal resistance of the electric double layer capacitor 100, and FIG. 2A in the figure shows a time change of the current supplied to the electric double layer capacitor 100. (B) shows the time change of the element voltage of the electric double layer capacitor 100. In this figure, three different methods for measuring the internal resistance are shown. In the inspection step of the electric double layer capacitor 100, all of these measurement methods may be carried out and the inspection may be carried out based on the three measurement results, or only one or two arbitrary measurement methods may be carried out and one or two may be carried out. 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). At time t0, the supply of the predetermined charging current Ic to the electric double layer capacitor 100 is started, and then the supply of the constant charging current Ic is continued until the element voltage reaches the predetermined charging target voltage Vc. NS. In the figure, the electric double layer capacitor 100 is constantly charged with a constant current until the time t1 when the element voltage reaches the charging target voltage Vc.

Next, charging of the electric double layer capacitor 100 is temporarily suspended (time t1 to t2). The charging pause is a state in which current is not input / output from the inspection device 1 to the electric double layer capacitor 100, and continues from time t1 until a predetermined pause time T1 (for example, 1 second) elapses. .. In the figure, charging / discharging of the electric double layer capacitor 100 is suspended until time t2. Due to this charge suspension, the element voltage drops from Vt1 to Vn1.

During constant current charging, a voltage drop occurs in the internal resistance of the electric double layer capacitor 100 due to the inflow of charging current Ic, whereas this voltage drop does not occur during charging suspension, and the element is elementd by suspension of constant current charging. The voltage drops. Therefore, if the element voltages measured at times t1 and t2 are Vt1 and Vt2, the amount of change in the element voltage dV1 (= Vt1-Vt2) due to the suspension of constant current charging is the voltage drop of the internal resistance during constant current charging. It corresponds to a minute, and 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). Constant voltage charging of the charging target voltage Vc is started for the electric double layer capacitor 100 during charging suspension at time t2, and then constant voltage charging is continued until a predetermined charging time T2 (for example, 20 minutes) elapses. Will be done. In the figure, the electric double layer capacitor 100 is constantly charged at a constant voltage until time t3. During constant voltage charging, the charging current decreases with the passage of time, and the charging current becomes substantially zero by the time t3 when the constant voltage charging ends. The charging time T2 is predetermined as a sufficiently long time that the charging current can be made substantially zero. The end condition of constant voltage charging can also be specified by the detection current Id instead of the charging time T2.

Next, constant current discharge of the electric double layer capacitor 100 is performed (time t3 to t4). With respect to the electric double layer capacitor 100 being charged at a constant voltage, the extraction of a predetermined discharge current Ie is started at time t3, and then a constant discharge current is reached until the element voltage reaches a predetermined discharge end voltage Ve. Withdrawal of Ie is continued. In the figure, the electric double layer capacitor 100 is constantly discharged with a constant current until the time t4 when the element voltage reaches the discharge end voltage Ve. By the start of this discharge, the element voltage drops from Vc to Vr.

Just before the end of constant voltage charging, the charging current does not flow and no voltage drop occurs in the internal resistance, whereas during constant current discharge, the discharge current Ie is drawn out to the internal resistance of the electric double layer capacitor 100. A voltage drop occurs. This voltage drop is a voltage in the opposite direction to that during the pause (time t1 to t2), and the element voltage drops when the constant current discharge starts. That is, if the element voltage measured at time t3 is Vt3 (≈Vc), the amount of change in the element voltage dV2 (= Vt3-Vr) due to the start of constant current discharge is the voltage drop of the internal resistance at the time of constant current discharge. Equivalent to a minute. Therefore, if the amount of change in the element voltage dV2 is obtained, the internal resistance can be obtained by dV2 / IE.

Here, the amount of change dV2 of the element voltage at the start of discharge cannot be accurately measured, but the amount of change dV2 can be obtained with higher accuracy by linearly approximating the voltage characteristics during discharge. During constant current discharge, the element voltage decreases linearly with the passage of time. Therefore, the element voltage at two points P1 and P2 at different times during discharge is measured, the voltage characteristics during discharge are linearly approximated, and the voltage value Vr at the point where the approximate straight line and the time t3 intersect is obtained, and the time is obtained. If the difference from the element voltage Vt3 at t3 is obtained, the amount of change in the element voltage dV2 due to the start of discharge can be obtained with high accuracy.

Next, the discharge of the electric double layer capacitor 100 is stopped (time t4 to t5). Discharge pause is a state in which current is not input / output from the inspection device 1 to the electric double layer capacitor 100, as in the case of charge pause, and a predetermined pause time T3 (for example, 1 second) is set from time t4. It will continue until it elapses. In the figure, charging / discharging of the electric double layer capacitor 100 is suspended until time t5. Due to this discharge suspension, the element voltage rises from Ve to Vt5.

During constant current discharge, a voltage drop occurs in the internal resistance of the electric double layer capacitor 100 due to the withdrawal of the discharge current Ie, whereas this voltage drop does not occur during discharge suspension, and the element is caused by suspension of constant current discharge. The voltage rises. Therefore, if the element voltages measured at times t4 and t5 are Vt4 (≈Ve) and Vt5, the amount of change in the element voltage due to the suspension of constant current discharge dV3 (= Vt5-Vt4) is inside during constant current discharge. It corresponds to the voltage drop of the resistance, and the internal resistance can be obtained by dV3 / Ie.

When trying to measure the internal resistance with high accuracy using such a measurement method, the charging current Ic, the discharging current Ie, and the element voltage during constant voltage charging do not include ripples and are stable with high accuracy. There is a need. Further, the charging current Ic and the discharging current Ie need to have a high response characteristic that quickly rises at the start of charging / discharging. Further, it is necessary that the element voltage can be measured with high accuracy. In particular, it is required that the element voltage can be measured with high accuracy even during the pause of charging / discharging. The inspection device 1 according to the present embodiment is a device that satisfies such conditions and can measure the internal resistance with high accuracy, and the detailed configuration thereof will be further described.

<Outline configuration of inspection device 1>
FIG. 3 is a diagram showing a configuration example of the inspection device 1 of FIG. The inspection device 1 is composed of a plurality of power supply circuits 111 to 113 composed of switching regulators (SWRs), a main circuit unit 114 including a series regulator (SRR), and a control unit 115.

(1) Power supply circuits 111-113
The power supply circuits 111 to 113 are switching regulators that convert an external power supply and output DC voltages Vs1 to Vs3. The first power supply circuit 111 is a variable power supply that outputs a voltage Vs1 to the main circuit unit 114. The output voltage Vs1 is specified by the 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 source for the 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 specified by the voltage command value Cv2 from the control unit 115. For example, the second power supply circuit 112 can supply 3.3V to 0V as a power supply for the discharge operation.

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

(2) Main circuit unit 114
The main circuit unit 114 is a circuit board constituting 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 them via the output terminal 12. , Controls the charge and discharge of the electric double layer capacitor 100.

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

Further, the control unit 115 can detect the element voltage Vrm via 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. Further, the control signal from the user terminal 103 is received via 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 composed of transistors TR1 to TR4. The elements shown by rectangles in the figure and not specifically mentioned are resistors.

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

The transistor TR1 is an NPN type bipolar transistor constituting an emitter follower circuit, _{and a collector current obtained by amplifying a base current with a 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 type bipolar transistor constituting an emitter follower circuit, _{and a collector current obtained by amplifying a base current with a 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 a common emitter terminal of the transistors TR3 and TR4 is connected to a common base terminal of the transistors TR1 and TR2. By connecting the two-stage push-pull circuits PP1 and PP2, the transistors TR1 and TR3 are Darlington-connected, and the transistors TR2 and TR4 are also Darlington-connected, increasing the _{current amplification factor hEF in both charging and discharging.} Can be made to. 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 TR1 to TR4 are all elements that amplify current, and do not perform on / off operations like the transistors that make up a switching regulator. Therefore, a highly stable output without ripples can be obtained. Further, since a smoothing process using a capacitive element is not required, good responsiveness can be ensured. Therefore, the internal resistance of the electric double layer capacitor 100 can be measured with high accuracy.

(3) Output terminal 12
The positive electrode side 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. Further, the negative electrode side 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 resistance SH
The shunt resistor SH is a resistance element for detecting an output current, and is provided on the push-pull circuit PP1 side of the output relay RY1. The voltage between the 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 cutting off a pair of wirings 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 are closed together when the electric double layer capacitor 100 is charged and discharged, and the electric double layer capacitor 100 is a push-pull circuit. While connected to PP1, the other parts are both open, 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 the output of the series regulator SRR is cut off. By providing such output relays RY1 and RY2, current input / output can be completely cut off during charging / discharging suspension, and internal resistance can be measured with high accuracy. In addition, it is possible to prevent inadvertent current output during standby and improve safety.

The capacitance 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 device 1 are always connected at high frequencies via the capacitance 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 being in a floating state with respect to the inspection device 1. Therefore, it is possible to prevent the measurement accuracy of the element voltage Vrm during the pause of charging / discharging when the relays RY1 and RY2 are in the open state from being lowered due to the influence of the common mode (in-phase voltage) noise in the 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 the control target, obtains 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. Obtain the operation amount Ui. The detected current Id is the output of the controlled object, and the current command value Iref is the target value of the controlled object, which is given by the control unit 115. The manipulated variable 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 detector 3
The output voltage detection unit 3 measures the voltage between the output terminals 12 on the output terminal 12 side of the output relays RY1 and RY2, and outputs the voltage as the detection voltage Vd. This detected 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 detected voltage Vd and the manipulated variable Ui, and is composed of the operational amplifier OP1 and the resistors R1 to R3.

The operational amplifier OP1 is an amplifier circuit that applies an input voltage to the push-pull circuit PP2 in the previous stage, and is an inverting amplifier that feeds back the output voltage of the push-pull circuit PP1 in the subsequent stage to the inverting input terminal via a resistor R3. An inverting signal of the detection voltage Vd is input to the inverting input terminal of the operational amplifier OP1 via the resistor R1, and an inverting signal of the operation amount Ui generated by the current feedback circuit 2 is connected via 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 expressed as a weighted sum (linear sum) of the detected voltage Vd and the manipulated variable 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 detected voltage Vd and the manipulated variable Ui.

In the output control circuit 4, the detection voltage Vd is added to the manipulated variable Ui, and the feedback control of the output current using the manipulated variable Ui and the feedforward control of the output voltage using the detected voltage Vd are performed at the same time. When the operation amount Ui obtained from the detection current Id is fed back to control the output voltage, the operation amount Ui of the feedback control is offset by adding the detection voltage Vd to the operation amount Ui, and the center of the change range is set. It can be matched to the current output voltage. Therefore, the feedback control can be performed more effectively, and the responsiveness can be improved.

Further, by adding the detection voltage Vd to the operation amount Ui, the voltages across the output relay RY1 in the open state can be matched. As will be 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 across the output relay RY1 in the open state. If the output relay RY1 is turned on in this state, an inrush current flows due to the potential difference. On the other hand, if the output voltage is controlled by using the value obtained by adding the detection voltage Vd to the manipulated variable Ui, the voltages across the output relay RY1 in the open state can be matched. As a result, it is possible to prevent an inrush current from flowing when the output relay RY1 is turned on, and it is possible to improve the responsiveness of the current output immediately after the output relay RY1 is turned 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 between the terminals of the shunt resistor SH, outputs the detected current Id, and obtains the operation amount Ui of PI control with the current command value Iref as the target value. The illustrated current feedback circuit 2 is composed of 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 composed of an operational amplifier OP2 and a resistance element, and amplifies the voltage between terminals of the shunt resistor SH to obtain the detection current Id. The detection current Id is output to the inverting amplifier circuit A2 and also to the control unit 115.

(2) Inversion amplifier circuit A2
The inverting amplifier circuit A2 is composed of an operational amplifier OP3 and a resistance element, generates an inverting signal in which the sign of the detection current Id is inverted, and inputs it to the PI control circuit A3.

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

Further, a feedback circuit including a series circuit of the resistor R6 and the capacitance 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) and an integrated value (I) with respect to the input value. Output the sum of the components). With such a configuration, the PI calculation for the detected current Id is performed, and the inverted signal of the manipulated variable Ui used in the PI control is generated.

Further, an invalidation switch AS is connected in parallel to the feedback circuit of the operational amplifier OP4. The invalidation switch AS is a switch that invalidates PI control by short-circuiting between the inverting input terminal and the output terminal of the operational amplifier OP4, and for example, an analog switch is used. The invalidation switch AS operates based on the invalidation signal Cas from the control unit 115. During PI control, the invalidation signal Cas becomes inactive and the invalidation switch AS is in the open state, while when idle without PI control, the invalidation signal Cas becomes active and the invalidation switch AS is in the closed state. Become. When the invalidation switch AS is closed, the operation amount Ui becomes zero regardless of the input value to the operational amplifier OP4, and the PI control is invalidated.

When the output relay RY1 is in the open state and the output relay RY1 is blocking the output, the operation amount Ui of PI control is not reflected in the detection current Id. Therefore, the feedback control of the output current does not function normally, and the output voltage of the series regulator SRR cannot be determined.

For example, even if the current command value Iref is set to zero, in analog control, the detected current Id does not completely match the current command value Iref, 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 detection current Id, and the manipulated variable Ui monotonously increases or decreases with the passage of time, and is shaken off until it reaches the maximum value or the minimum value. It ends up.

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

<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 is composed of 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 retains the electrical characteristics of the wiring cable 101 that connects 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. This wiring characteristic Cz is input in advance by the user operation on the user terminal 103 or the inspection device 1 before the inspection of the electric double layer capacitor 100 is started.

(2) Element 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, the element voltage Vrm of the electric double layer capacitor 100 can be accurately detected by using the four-terminal method. Further, the element voltage Vrm can be detected even when the output relays RY1 and RY2 are in the open state.

For the element voltage detection unit 41, 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 is used. In particular, it is desirable to use an instrumentation amplifier. Since the instrumentation amplifier has a good common mode elimination ratio, the element voltage Vrm can be measured more accurately. However, even if an instrumentation amplifier is used, it is difficult to sufficiently eliminate the influence of the common mode in the high frequency region. Therefore, the capacitive 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 opened, the electric double layer capacitor 100 is insulated from the ground of the element voltage detection unit 41 and becomes a floating state with respect to the element voltage detection unit 41. If the element voltage Vrm is measured in this state, the measurement accuracy of the element voltage Vrm is lowered due to the influence of the common mode noise.

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

(3) Voltage control unit 42
The voltage control unit 42 generates voltage command values Cv1 and Cv2 based on the wiring characteristic Cz and the element voltage Vrm, and controls the output voltages Vs1 and Vs2 of the power supply circuits 111 and 112. This voltage control reduces the heat loss that occurs in the transistors Tr1 and Tr2.

The transistors TR1 and TR2 constituting the emitter follower circuit generate a loss according to 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, it is a condition 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 output voltages Vs1 and Vs2 as small as possible within 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。 The output voltage Vs1 of the power supply circuit 111 is represented by the following equation using the collector-emitter voltage Vce of the transistor TR1, the voltage drop (Cz × Id) in the wiring cable 101, and the element voltage Vrm of the electric double layer capacitor 100. be able to.

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

The voltage drop (Cz × Id) in the second term is a value proportional to the output current of the inspection device 1. As shown in FIG. 2A, the current changes instantaneously at the start of charging / discharging. In the case of the inspection device 1 according to the present embodiment, the rise time of the charge / 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, it is necessary to anticipate the maximum value of the voltage drop (Cz × Id) in advance. That is, since the maximum value of the output current during the charging operation is the charging current Ic, it is necessary to anticipate (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 that changes according to the state of charge. However, as shown in FIG. 2B, the change in the element voltage Vrm during charging / discharging is extremely gradual as compared with the change in the voltage drop of the wiring cable 101. Therefore, the value detected by the element voltage detection unit 41 can be used for the Vrm of the third term.

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, the voltage command value Cv1 can be obtained by the following equation.

The command value Cv2 of the power supply circuit 112 is the same except that the direction of the current is opposite to the voltage command value Cv1. Since the maximum value of the output current during the discharge operation is Ie, the voltage command value Cv2 is also as follows. It can be calculated by the formula 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 that changes during the charge / discharge operation. Therefore, the voltage control unit 42 determines the voltage command values Cv1 and Cv2 using these equations. That is, the 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 device 1 according to the present embodiment separately obtains the voltage drop of the wiring cable 101 and the element voltage Vrm of the electric double layer capacitor 100 by measuring the element voltage Vrm by the four-terminal method. Therefore, voltage control based on the element voltage Vrm can be performed. As described above, the change of the former is difficult to follow by voltage control, while the change of the latter is relatively easy to follow by voltage control. Voltage control based on voltage Vrm can be realized, and heat loss can be reduced.

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

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

<Measurement sequence>
Steps S1 to S5 of FIG. 7 are flowcharts showing an example of the measurement sequence of the internal resistance by the inspection device 1, and show the operation of the sequence control unit 43 of FIG. This flowchart is executed by a measurement start command from the user terminal 103. As a preliminary preparation, the wiring characteristic Cz of the wiring cable 101 is specified by the user terminal 103. Further, 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 the measurement start command is input, the sequence control unit 43 determines the constant current charging process (step S1) for supplying the charging current Ic, the charging pause process (step S2) for suspending the constant current charging, and the charging target voltage Vc. The constant voltage charging process (step S3) for charging the voltage, the constant current discharge process (step S4) for drawing out the discharge current Ie, and the discharge pause process (step S5) for suspending the constant current discharge are executed in order. Details of each of these processes will be described in order.

(1) Constant Current Charging Process Steps S101 to S104 of FIG. 8 are flowcharts showing an example of detailed operation of the constant current charging process (step S1) of FIG. 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, and current output becomes possible (step S101). Since both ends of the output relay RY1 in the open state are held at the same potential by the feed forward control of the detection voltage Vd, the inrush current does not flow through the electric double layer capacitor 100 by the ON operation of the output relay RY1. Next, the sequence control unit 43 inactively changes the invalidation signal Cas. As a result, the invalidation switch AS is opened and PI control is enabled (step S102).

Next, the sequence control unit 43 changes the current command value Iref to a 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 that in the case where the current is controlled 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 when the element voltage Vrm reaches the charging target voltage Vc (step S104).

(2) Charging Suspension Processing Steps S201 to S205 of FIG. 9 are flowcharts showing an example of detailed operation of the charging suspension processing (step S2) of 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. The suspension of charging is performed by disabling PI control and turning off the output relays RY1 and RY2 (steps S202 and S203).

In order to suspend charging, the sequence control unit 43 first actively changes the invalidation signal Cas to invalidate the PI control (step S202). By disabling the PI control during charging suspension, it is possible to prevent the control of the series regulator SRR from running out of control during idling.

Next, the sequence control unit 43 changes the relay control signal Cry to an off signal, so that the output relays RY1 and RY2 are opened and charging by the inspection device 1 is stopped (step S203). By turning off the output relays RY1 and RY2 and disconnecting the electric double layer capacitor 100 from the series regulator SRR during charging suspension, the current input / output to the electric double layer capacitor 100 can be completely cut off during charging suspension.

After that, when the predetermined pause time T1 (for example, 1 second) elapses (step S204), the sequence control unit 43 measures the element voltage Vrm (Vt2) and ends the charge pause process (step S205). When the element voltage Vt2 is measured, the output relays RY1 and RY2 are in the open state, but since both ends of the output relay RY2 on the negative electrode side are connected at high frequencies via the capacitive element C1, the influence of common mode noise is affected. It can be suppressed and the element voltage Vt2 can be measured with high accuracy.

(3) Constant Voltage Charging Process Steps S301 to S304 in FIG. 10 are flowcharts showing an example of detailed operation of the constant voltage charging process (step S3) in FIG. When the charge 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, so that the output relays RY1 and RY2 are closed and current output becomes possible (step S301). Since both ends of the output relay RY1 in the open state are held at the same potential by the feed forward control of the detection voltage Vd during the charging suspension, an inrush current flows through the electric double layer capacitor 100 when the output relay RY1 is turned on. There is no. Next, the sequence control unit 43 inactively changes the invalidation signal Cas, so that the invalidation switch AS is opened and PI control is enabled (step S302).

After that, 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 the error (Vc-Vrm) of the element voltage Vrm with respect to the charging target voltage Vc. After that, when the predetermined charging time T2 (for example, 20 minutes) elapses, the constant voltage charging process ends (step S304).

(4) Constant Current Discharge Processing Steps S401 to S404 of FIG. 11 are flowcharts showing an example of detailed operation of the constant current discharge processing (step S4) of 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).

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

The sequence control unit 43 periodically repeats the measurement of the detected current Id and the element voltage Vrm during the constant current discharge, and ends the constant current discharge process when the element voltage Vrm reaches the discharge end voltage Ve (step S404). ).

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

In order to suspend the discharge, the sequence control unit 43 first actively changes the invalidation signal Cas to invalidate the PI control (step S502). By disabling the PI control during discharge suspension, it is possible to prevent the control of the series regulator SRR from running out of control during idling.

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

After that, when the predetermined pause time T3 (for example, 1 second) elapses (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 side are connected at high frequencies via the capacitive element C1, so that the influence of common mode noise is affected. It can be suppressed and the element voltage Vt5 can be measured with high accuracy.

Embodiment 2.
In the first embodiment, an example in which the wiring characteristic Cz specified by the user is maintained has been described. On the other hand, in the present embodiment, the inspection device 1 that measures and holds the wiring characteristic Cz in advance will be described.

FIG. 13 is a diagram showing a main part of the inspection device 1 according to the second embodiment of the present invention, and shows another configuration example of the control unit 115. The control unit 115 of FIG. 13 is different from the case of FIG. 6 (Embodiment 1) in that it includes a wiring characteristic detection unit 50 and a wiring characteristic determination unit 51. In the embodiment, only the differences from the first embodiment will be described, and duplicate 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 a ratio of the current flowing through the wiring cable 101 and the voltage drop at that time if it can be acquired. The voltage drop of the wiring cable 101 is given as the difference between the detected 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 device 1, and the detected wiring characteristic Cz is stored in the wiring characteristic storage unit 40 and used for the subsequent internal resistance measurement. Will be done.

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

If the output time is short, the influence on the inspection device 1 is small even if the voltage command values Cv1 and Cv2 based on the wiring characteristic Cz are not controlled. Therefore, if the wiring characteristic Cz is measured and stored in the first short time after the start of the internal resistance measurement and then the stored wiring characteristic Cz is used, wiring is performed before the start of the internal resistance measurement. It is not necessary to make advance preparations for measuring the characteristic Cz. Further, if the wiring characteristics are automatically measured every time the internal resistance measurement is started, the loss can be reduced even when the wiring or equipment is changed by the user.

(2) Wiring characteristic determination unit 51
The wiring characteristic determination unit 51 determines whether or not the wiring characteristic Cz detected by the wiring characteristic detection unit is an abnormal value, and outputs an alert 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 limit threshold value 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 a voice output in the inspection device 1.

Further, the wiring characteristic determination unit 51 is given an upper limit threshold value Cmax and a lower limit threshold value Cmin in advance, can compare the wiring characteristic Cz with the respective threshold values Cmax and Cmin, respectively, and can output an alert based on these 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 if it is out of the range, an alert output may be performed.

According to this embodiment, since it is not necessary for the user to specify the wiring characteristic Cz, it is not necessary to perform complicated setting work. Further, an appropriate internal resistance measurement can be performed by using the accurate wiring characteristic Cz of the actual wiring cable 101. As a result, when the user specifies an erroneous wiring characteristic Cz, an excessive current flows and the inspection device 1 is thermally destroyed, or an excessive current flows and the internal resistance cannot be measured. Can be done. Further, when the wiring cable 101 having an inappropriate wiring characteristic Cz is connected to the inspection device 1, an alert output can be output to notify the user.

In the embodiment, an example in which a current smaller than that in the measurement of internal resistance is passed when detecting the wiring characteristics has been described, but the present invention is not limited to such a case. For example, when detecting the wiring characteristics, the same current as the current (particularly the maximum current) at the time of measuring the internal resistance is passed, the voltage drop (Vd-Vrm) in the wiring cable 101 at that time is obtained, and this voltage drop is held as the wiring characteristics Cz. , Can also be used for voltage control.

Further, in the embodiment, an example in which the wiring characteristic determination unit 51 determines the wiring characteristic detected by the wiring characteristic detection unit 50 and outputs an alert based on the determination result has been described. However, the present invention describes the present invention. It is not limited to such a case. For example, the wiring characteristic determination unit 51 may determine the wiring characteristic specified by the user, and an alert output may be output based on the determination result.

1 Inspection device 2 Current feedback circuit 3 Voltage detection unit 4 Output control unit 100 Electric double layer capacitor 101, 102 Wiring cable 103 User terminal 111-113 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 amplification circuit (current detection unit)
A2 Inversion amplifier circuit A3 PI control circuit AS Invalidation switch C, C1, C2 Capacitive element Cas Invalidation signal Cry Relay control signal Cv1, Cv2 Voltage command value dV1 to dV3 Voltage drop width Ic Charge current Ie Discharge current Id Detection current Iref Current Command value OP1 to OP4 Amplifiers PP1, PP2 Push-pull circuit R1 to R6 Resistance Rp Parallel internal resistance Rs Series internal resistance (internal resistance)
RY1, RY2 Output relay SH Shunt resistance SRR series Regulator SWR Switching regulator TR1 to TR4 Transistor Ui Operation amount Vc Charge target voltage Ve Discharge end voltage Vs1 to Vs3 Power supply voltage Vd Detection voltage Vrm, Vt2, Vt3, Vt5 Element voltage

Claims (5)

In an inspection device that measures the internal resistance of an electric double layer capacitor by performing constant current charging or constant current discharging.
The output terminal to which the above electric double layer capacitor is connected and
A power supply circuit that outputs current to the electric double layer capacitor via the output terminal,
An output relay that cuts off the output of the power supply circuit between the power supply circuit and the output terminal,
A current detector that measures the output current of the power supply circuit as a detection current,
A current feedback circuit that obtains the amount of operation to match the detected current with the current command value, and
It is provided with an output control circuit that controls the output of the power supply circuit based on the operation amount.
The current feedback circuit is an inspection device characterized in that when the output relay is in a cutoff state, zero is output as the operation amount regardless of the operation amount obtained from the detection current. The current feedback circuit has a PI calculation circuit for obtaining the manipulated variable by performing a PI calculation on the deviation of the detected current with respect to the current command value.
The inspection device according to claim 1, wherein when the output relay is in a cutoff state, the PI calculation is invalidated and zero is output as the operation amount. The PI calculation circuit includes an operational amplifier, a series circuit of resistors and capacitive elements that feed back the output of the operational amplifier to the inverting input terminal, and an analog switch connected in parallel to the series circuit.
The inspection device according to claim 2, wherein when the current command value is zero, the output relay is cut off, the analog switch is short-circuited, and zero is output as the operation amount. .. Equipped with a voltage detector that measures the output voltage of the power supply circuit as the detection voltage
The inspection device according to any one of claims 1 to 3, wherein the output control circuit controls the output voltage of the power supply circuit based on the detected voltage and the manipulated variable. The inspection device according to claim 4 , wherein the voltage detection unit measures the output voltage of the power supply circuit on the output terminal side of the output relay.

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