JP6004859B2 - Electrochemical measuring device and charge / discharge control method for electrochemical measuring device - Google Patents

Description

  The present invention relates to an electrochemical measurement device for measuring, for example, a storage battery or a capacitor, and a charge / discharge control method thereof, and in particular, charge / discharge of constant voltage from charge / discharge control of constant current / constant power / constant resistance to the device to be controlled It relates to transition control to control.

  The charge / discharge function in the electrochemical measurement device performs constant current / constant power / constant resistance control to charge / discharge batteries and capacitors, and when the voltage reaches the set voltage, the current value is narrowed down to control the constant voltage from constant current control. Control to transition to.

  FIG. 1 shows an example of a block diagram of a control unit of an electrochemical measurement device. Reference numeral 101 denotes a storage battery as a measurement target device, and one end of a current detection resistor 102 is connected to the positive end of the storage battery.

  An input terminal of a voltage detection circuit 103 composed of an operational amplifier is connected to the positive and negative terminals of the storage battery 101, and an input terminal of a current detection circuit 104 composed of an operational amplifier is connected to both ends of the current detection resistor 102.

  Reference numeral 105 denotes an AD converter for voltage detection that performs analog-digital conversion on the detection voltage output from the voltage detection circuit 103 and outputs the converted voltage to a CPU (computer) 120.

  Reference numeral 106 denotes an AD converter for current detection that performs analog-digital conversion on the detection current output from the current detection circuit 104 and outputs the result to the CPU 120.

  The CPU 120 takes in the output signals of the AD converters 105 and 106 and outputs a charge / discharge current / power / resistance command signal and a charge / discharge voltage command signal (control signal) for the storage battery 101.

  Reference numeral 107 denotes a DA converter that performs digital-analog conversion on a command signal output from the CPU 120. An output signal (control command) of the DA converter 107 is input to one input terminal of a voltage / current control circuit 109 having an operational amplifier via a resistor 108.

  Between the output terminal of the current detection circuit 104 and one input terminal of the voltage / current control circuit 109, a resistor 111 and a current control switch SW1 are connected in series.

  A resistor 112 and a voltage control switch SW2 are connected in series between the output terminal of the voltage detection circuit 103 and one input terminal of the voltage / current control circuit 109.

  The other input end of the voltage / current control circuit 109 is grounded, and the output end is connected to the other end of the current detection resistor 102.

  For example, the following Patent Document 1 has been proposed as a charge / discharge test system and method for a power storage device.

JP 2010-114970 A

  In the apparatus of FIG. 1, when potential control called potentiostat is performed, the switch SW1 is opened and the switch SW2 is closed. At this time, the control value given from the CPU 120 is outputted from the DA converter 107, and the circuit operates so as to keep the voltage of the storage battery 101 at this value.

  When current control called galvanostat is performed, the switch SW1 is closed and the switch SW2 is opened. At this time, the current flowing through the storage battery 101 is controlled according to the value output from the DA converter 107. In this electrochemical device, charge / discharge measurement may be performed. In particular, an operation for controlling to constant voltage control when the voltage of the storage battery 101 reaches a target value by controlling with a constant current is required.

  In a normal electrochemical measurement apparatus, constant current-constant voltage switching control can be realized by switching the switches SW1 and SW2 of the control circuit. In this case, it is difficult to completely match the timing of the output change of the DA converter 107 (necessary because the control value differs between constant current control and constant voltage control) and the switching timing of the switches SW1 and SW2, and the switch switching itself. Causes an unstable circuit condition, so that a large electrical shock is applied to a test object such as a battery or a capacitor (storage battery 101 in FIG. 1), which greatly affects the safety and accuracy of the test. It becomes.

  In addition, there is an example in which digital control as disclosed in Patent Document 1 is performed in a charging / discharging tester for a storage element such as a secondary battery, but since the control is performed at the AD sampling cycle, the noise component of the measurement voltage Instability and control delay due to the problem were issues. In this control, since the control behavior differs depending on the combination of the properties of the connected sample and the control algorithm, it was difficult to grasp what control was actually performed based on the measurement result alone.

  The present invention solves the above-described problems, and an object of the present invention is to provide an electrochemical measurement apparatus that does not cause a control delay at the time of transition from constant current / constant power / constant resistance control to constant voltage control, and its charge / discharge control. It aims to provide a method.

The electrochemical measurement apparatus according to claim 1 for solving the above-mentioned problem is a method for detecting a charge / discharge voltage and a charge / discharge current of a measurement target apparatus in the electrochemical measurement apparatus and inputting an analog-digital converted signal by an AD converter. And a computer that outputs a charge / discharge current / power / resistance command signal and a charge / discharge voltage command signal for the measurement target device, and a signal obtained by digital-analog conversion of the command signal output from the computer by a DA converter. An electrochemical measurement apparatus comprising a charge / discharge voltage and a voltage / current control circuit for controlling a charge / discharge current of a measurement target apparatus, wherein the computer outputs a current command signal to output a constant current / constant power / constant resistance When the control is started and the voltage of the measurement target device reaches the target voltage, the current command signal is a value corresponding to the target voltage. Switching to constant voltage control, and at the time of constant voltage control after the transition, constant voltage control based on the data obtained by averaging the detected voltage of the measurement target device sampled at a cycle shorter than the execution cycle of the constant voltage control Control means for controlling the current at the constant voltage control execution cycle in accordance with the processing procedure of
In the control means, the detected voltage of the measurement target device exceeds a target voltage for constant voltage control, and a current setting value for performing constant voltage control is determined by a current range and resolution of the DA converter and AD converter. When the current set value is less than the minimum value, the current set value is set to a value opposite to the current current polarity and larger than the minimum value. Thereafter, the detected voltage of the measurement target device does not reach the target voltage and is constant. When the current setting value for voltage control is less than the minimum value determined by the resolution of the current range and the DA converter and AD converter, the current setting value is set to the current polarity before the reverse polarity is set. It is characterized by having means for setting to the minimum value .

According to a fourth aspect of the present invention, there is provided a method for controlling charge / discharge of an electrochemical measurement device, wherein the charge / discharge voltage and charge / discharge current of the measurement target device in the electrochemical measurement device are detected and an analog-digital converted signal is input by an AD converter And a computer that outputs a charge / discharge current / power / resistance command signal and a charge / discharge voltage command signal for the measurement target device, and a signal obtained by digital-analog conversion of the command signal output from the computer by a DA converter. A charge / discharge control method for an electrochemical measurement device comprising a charge / discharge voltage of a measurement target device and a voltage / current control circuit for controlling a charge / discharge current, wherein the control means of the computer outputs a current command signal. When the constant current / constant power / constant resistance control is started and the voltage of the measurement target device reaches the target voltage, the current command signal Switching to a value corresponding to the target voltage and transitioning to constant voltage control, and after the transition, based on data obtained by averaging the detected voltages of the measurement target devices sampled at a cycle shorter than the execution cycle of the constant voltage control And a constant voltage control step for controlling current in a constant voltage control execution cycle according to a constant voltage control processing procedure ,
In the constant voltage control step, the detected voltage of the measurement target device exceeds a target voltage for constant voltage control, and the current setting value for performing constant voltage control is a current range and resolution of the DA converter and AD converter. When the current set value is less than the minimum value determined by the above, the current set value is set to a value opposite to the current current polarity and larger than the minimum value, and then the detection voltage of the measurement target device does not satisfy the target voltage. In addition, when the current set value for performing the constant voltage control becomes less than the minimum value determined by the resolution of the current range and the DA converter and AD converter, the current set value is set to the current before the reverse polarity is set. The step of setting to the minimum value of the polarity is provided .

  According to the above configuration, no control delay occurs at the time of transition from constant current / constant power / constant resistance control to constant voltage control. In other words, the voltage value is sampled at a cycle shorter than the execution cycle of the constant voltage control, and the constant voltage control is performed based on the averaged data. The convergence of the control current can be accelerated by reducing the fluctuation.

In addition, since there is no hardware switching at the time of transition from constant current / constant power / constant resistance control to constant voltage control, electrical shock such as voltage overshoot is suppressed, and quick transition is executed.
In addition, since the minimum value that can be reflected in the DA converter and AD converter is determined when the control current value is narrowed down, it is possible to limit the setting of the current value in the calculation of an ineffective computer, This can prevent a control delay from occurring.

  The electrochemical measurement device according to claim 2 is the electrochemical measurement device according to claim 1, wherein the control means converts the current into a current increase / decrease coefficient when a detection voltage of the measurement target device exceeds a target voltage for constant voltage control. If the current does not reach the target voltage, the current increasing / decreasing means for each of the constant voltage control execution cycles and the current increasing / decreasing process are continuously performed. The method is characterized by comprising coefficient changing means for increasing the current increase / decrease coefficient when it is executed more than the set number of times.

Moreover, the charge / discharge control method for an electrochemical measurement device according to claim 5 is the method according to claim 4 , wherein the constant voltage control step is performed when a detected voltage of the measurement target device exceeds a target voltage for constant voltage control. Reduces the current by the current increase / decrease coefficient, and if the target voltage is not reached, the current increase / decrease step is performed for each execution period of the constant voltage control, and the current is increased by increasing the current by the current increase / decrease coefficient. And a coefficient changing step for increasing the current increase / decrease coefficient when the process of decreasing is continuously executed a set number of times or more.

  According to the said structure, the excessive change of the control current for performing constant voltage control can be suppressed.

Further, the electrochemical measuring apparatus according to claim 3, in claim 1 or 2, wherein the computer, the control means is a flow chart of the procedure of the constant voltage control performed by the in flow chart is executed when the constant voltage control It is characterized by comprising means for creating and recording a control log including the data of the control path.

A charge / discharge control method for an electrochemical measurement apparatus according to claim 6 is a flowchart of a constant voltage control processing procedure performed by the control means of the control log creation / recording means of the computer according to claim 4 or 5 . And generating a control log including control path data in the flowchart executed during the constant voltage control, and executing a control log creating / recording step.

  According to the above configuration, the operation process of the constant voltage control can be left as a record of the control path on the flowchart, and it is possible to grasp what control path the constant voltage control is actually performed on.

(1) According to the first to sixth aspects of the invention, it is possible to prevent the occurrence of a control delay at the time of transition from constant current / constant power / constant resistance control to constant voltage control.
In addition, since the minimum value that can be reflected in the DA converter and AD converter is determined when the control current value is narrowed down, it is possible to limit the setting of the current value in the calculation of an ineffective computer, This can prevent a control delay from occurring.
(2) According to the second and fifth aspects of the invention, the current set value for performing the constant voltage control can be appropriately increased and decreased, and an excessive change in the control current can be suppressed.
(3) According to the invention described in claims 3 and 6 , the operation process of the constant voltage control can be recorded as a record of the control path on the flowchart, and the constant voltage control is actually performed in any control path. It becomes possible to grasp.

  This makes it easy to verify and correct which part of the constant voltage control processing procedure has a problem and improve the efficiency of algorithm and device development. In addition, it is possible to provide new user support in a form different from conventional ones, such as specific presentation of the cause of the problem and the mechanism to the user of the charge / discharge function of the electrochemical measuring device.

The block diagram of the electrochemical measuring apparatus with which this invention is applied. The flowchart which shows the control procedure which the electrochemical measuring device of the embodiment of this invention performs. FIG. 3 is a partially enlarged view of the flowchart of FIG. 2. FIG. 3 is a partially enlarged view of the flowchart of FIG. 2. FIG. 3 is a partially enlarged view of the flowchart of FIG. 2. Explanatory drawing which shows an example of the control log produced by the example embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. Hereinafter, an embodiment in which the present invention is applied to the electrochemical measurement apparatus of FIG. 1 will be described.

  In this embodiment, the transition from constant current / constant power / constant resistance control to constant voltage control can be performed by digital control. During constant voltage control, a voltage control circuit (switch SW2 and voltage / current control circuit) can be used. 109) instead of the current control circuit (switch SW1 and voltage / current control circuit 109) (switch SW1 is closed and switch SW2 is opened), and CPU 120 generates current based on the detected voltage (output of AD converter 105). The voltage was kept constant by controlling. This is called constant voltage digital control. Therefore, switching of the control circuit does not occur in the charge / discharge function. Further, the CPU 120 is configured to record the operation process of the constant voltage digital control performed by itself in the apparatus.

  2 is a flowchart showing a control procedure (steps S1 to S35) executed by the CPU 120, FIG. 3 is an enlarged flowchart of steps S1 to S8 in FIG. 2, and FIG. 4 is an enlarged view of steps S9 to S27 in FIG. FIG. 5 is an enlarged flowchart of steps S28 to S35 in FIG. Here, the meanings of variables and terms used in FIGS.

Vset: target voltage for constant voltage control Vdet: average processing result of 100 detection voltages for 1 msec read from AD converter 105 for voltage detection at a period of 10 μsec Iset: constant current / constant power / constant Last current control setting value during resistance control ・ I: Current setting value, initial value is Iset
K: Current increase / decrease coefficient, initial value is 0.025
M: Current increase / decrease rate reduction coefficient, set value is 0.5
・ X: Threshold for increasing / decreasing current, initial value is 2mV
・ Imax: Current setting maximum value storage variable, initial value is 0
・ Imin: Current setting minimum value storage variable, initial value is 0
Flagx: Imax update flag, initial value is 0
Flag: Update flag for Imin, initial value is 0
CNTa: a counter that counts the number of passes through the control path (steps S19 to S27) for increasing the current set value I. CNTb: a counter that counts the number of passes through the control path (steps S10 to S16) for decreasing the current set value I. CNTc: a counter that counts the number of times that steps S18 and S28 are passed. CNTn: the difference between the detected voltage value Vdet and the target voltage Vset is within the threshold value X (the determination result in step S4 is No). ) Counter that counts the number ・ CNTup: Counter that counts the number of times that Imax is acquired and the current setting value I is increased (Step S27) in order to quickly converge the current value. • CNTdn: Current value converges quickly. In order to reduce the current setting value I, Imin was acquired (step S16). Counter for counting numbers 1 lsb: The minimum bit of the DA converter 107 and AD converters 105, 106, and the minimum value determined by the current range and the resolution of the DA converter 107, AD converters 105, 106, 2 lsb: Control A value set sufficiently higher than the minimum value 1 lsb (2 lsb is a value set in the present embodiment, and is not limited to this and may be 3 lsb)
Each of the determination steps represented by J1 to J8, J10, and J12 to J16 in FIGS. 2 to 5 indicates the number of the conditional branch of the control path.

  First, in FIG. 1 and FIG. 2, it is assumed that the switch SW1 is closed and the switch SW2 is opened, and constant current / constant power / constant resistance control is performed.

  In this state, when the condition of J1 is satisfied by the determination process of step S1, the process proceeds to constant voltage digital control. That is, the CPU 120 starts the constant voltage digital control from the moment when Vdet ≧ Vset when charging, and from the moment when Vdet ≦ Vset when discharging.

In step S2, the last current control set value Iset at the time of constant current / constant power / constant resistance control is set to the control value. In step S3, the current set value I is changed from the current control set value Iset to the current increase / decrease coefficient K ( The initial value is set to a value Iset * (1-K) reduced by 0.025), and the subsequent steps S4 to S35 are executed at a cycle of 1 msec.

  Therefore, in step S 3, the current setting value I at the first time of the constant voltage digital control is output from the DA converter 107.

  The CPU 120 obtains a detected voltage value at a 10 μsec period from the AD converter 105 for voltage detection separately from the execution period (1 msec) of steps S4 to S35, and averages 100 voltage values taken over 1 msec at a 10 μsec period. And used as a target voltage Vset for constant voltage control. As for the detected current, the detected current value obtained at a period of 10 μsec from the AD converter 106 is taken into the CPU 120 as described above. The sampling period of the detection voltage and detection current is not limited to the present embodiment, and may be another period.

  Next, in step S4 (conditional branch J2), it is determined whether or not the difference between the detected voltage (Vdet) and the set voltage (target voltage Vset) exceeds a threshold (allowable range) X for increasing or decreasing the current.

  If the determination result in step S4 is No, in steps S5 to S7, when the difference between the detected voltage and the set voltage is within the allowable range (X) for 8 consecutive times, the process of reducing the X is performed.

That increments the counter CNTn in step S5, the counter CNTn is 8 determines whether a (times) (conditional branch J3) in step S6, the coefficient threshold X in step S7 when it becomes 8 times N ( N = 1/2) to reduce (halve) X and reset counter CNTn.

  When the determination result of step S6 is No, and after the process of step S7, the process returns to step S4.

  As described above, when the state in which the difference between the reference voltage value Vset (target voltage) to be controlled and the detection voltage Vdet does not exceed the threshold value X is repeated eight times, the process of reducing the threshold value X by half is performed. The convergence degree of the control current is improved as compared with, for example, the control method shown in FIG.

  If the determination result in step S4 is Yes (the absolute value of the difference between Vdet and Vset exceeds the threshold value X), the counter CNTn is reset in step S8, and then step S9 in FIG. 2 and FIG. Go to J4).

  In step S9 (conditional branch J4), it is determined whether or not Vdet is smaller than Vset in the charging mode. In step S9, if the determination result is No (when the detection voltage Vdet exceeds the target voltage Vset), the current set value I is decreased (steps S10 to S16). If Yes (the detection voltage Vdet is the target voltage). When the voltage Vset is not reached, the current set value I is increased (steps S18 to S27), which becomes a branch point. In the discharge mode, it is determined in step S9 whether Vdet> Vset, that is, whether Vdet is greater than Vset.

  In step S10 (conditional branch J13), it is determined whether or not the current setting value I is equal to or greater than the minimum value +1 lsb of the DA converter 107 (in charge mode; whether or not I is equal to or less than −1 lsb in the discharge mode). .

  If the determination result in step 10 is Yes, it is determined in step S11 (conditional branch J16) whether the counter CNTb exceeds 3 (times) (whether the current set value I has been continuously decreased three times).

  When the counter CNTb exceeds 3, in step S12, the current increase / decrease coefficient K is divided by the current increase / decrease rate reduction coefficient M (set value 0.5) to obtain a large value (coefficient changing means). However, when K> 0.025, K = 0.025 so that the initial value 0.025 is not exceeded. Also, the counter CNTb is reset.

  In step S12, by multiplying the current increase / decrease coefficient K by the current increase / decrease rate reduction coefficient M in step S34, which will be described later, K is decreased, the change in the control current becomes too small, and the voltage control becomes insufficient. In order to prevent this, K is increased.

  When the determination result of step S11 is No and after the processing of step S12, the output current is reduced by multiplying the previous current setting value I by a coefficient (1-K) in step S13.

  In step S14, the counter CNTb is incremented, and the counter CNTa and the counter CNTc are reset.

  In step S15 (conditional branch J10), it is determined whether or not the update flag flagx of Imax is 1 (updatable), and if yes, the current setting minimum value storage variable Imin is set to the current set value in step S16. I is set, the update flag flag of Imin is set to 1, and the counter CNTdn is incremented. By acquiring Imin in step S16, the current value can be converged quickly.

  If the determination result in step S10 is No (that is, if the current setting value I is less than +1 lsb in the charge mode or greater than −1 lsb in the discharge mode), in step S17, the charge mode is I is set to -2 lsb, and I is set to +2 lsb in the discharge mode.

  In this step S17, even if the minimum value 1lsb of the resolution of the DA converter 107 is changed, there is no clear difference in actual operation. Yes. Further, since this 2lsb has the opposite polarity to the original current setting value I, it is equivalent to actually changing 3lsb (= 1 lsb − (− 2 lsb)).

  The reason why the reverse polarity 2lsb is set in step S17 is to cope with the offset of the circuit. Ideally, + 1lsb should be the charging current and -1lsb should be the discharging current. However, due to a physical error in the circuit, even if 0 lsb is set, the flowing current is not 0 but a slightly positive current (charging current) may flow. Step S17 is a step executed in order to detect this state and to reliably set the charging current to zero. However, in some cases, a slight discharge current may flow due to the process of step S17. Therefore, in order to cope with this, a process of restoring the current direction is performed in step S20 described later.

  The 2lsb is not limited to this and is set to other values according to the circuit configuration.

  When the determination result of step S15 is No, after execution of step S16, and after execution of step S17, the process returns to step S4.

  Next, when the determination result of step S9 is Yes (when the detection voltage Vdet is less than the target voltage Vset), the update flag flagx of Imax can be updated (flagx = 1) and Imin in step S18 (conditional branch J5). It is determined whether or not the update flag flag is updated (flag = 1).

  If the determination result in step S18 is No (when updating is not possible), in step S19 (conditional branch J12), it is determined whether or not the current setting value I is smaller than the minimum value (+1 lsb) of the DA converter 107 (charging). Mode: It is determined whether or not I is larger than −1 lsb in the discharge mode).

  If the determination result in step S19 is Yes, there is a possibility that the discharge current flows in the charge mode and the charge current flows in the discharge mode by setting I so that the reverse polarity current flows in step S17. Therefore, in step S20, I = + 1 lsb (during charging) and I = −1 lsb (during discharging) are set to return the current direction to the original direction.

  When the determination result of step S19 is No, and after execution of step S20, the counter CNTa exceeds 3 (times) in step S21 (conditional branch J15) (the current set value I is continuously increased three times). ) Or not.

  When the counter CNTa exceeds 3, in step S22, the current increase / decrease coefficient K is divided by the current increase / decrease rate reduction coefficient M (set value 0.5) to obtain a large value (coefficient changing means). However, when K> 0.025, K = 0.025 so that the initial value 0.025 is not exceeded. Also, the counter CNTa is reset.

  When the determination result of step S21 is No and after execution of step S22, it is determined in step S23 (conditional branch J14) whether I * (1 + K) is equal to or less than the current control set value Iset (in charge mode). In the discharge mode, it is determined whether or not I * (1 + K) is equal to or greater than the current control set value Iset).

  If the determination result in step S23 is Yes, the current set value I is set to I * (1 + K) (the output current is increased by multiplying the previous I by a coefficient (1 + K)).

  If the determination result of step S23 is No, the current set value I is set to the current control set value Iset in step S25.

  In step S26, the counter CNTa is incremented and the counters CNTb and CNTc are reset.

  In step S27, the current setting maximum value storage variable Imax is set to the current setting value I, the update flag flagx of Imax is set to 1, and the counter CNTup is incremented. By acquiring Imax in step S27, the current value can be converged quickly. After execution of step S27, the process returns to step S4.

  When the determination result in Step S18 is Yes (when both the Imax update flag and the Imin update flag can be updated), the counter CNTc is incremented in Step S28 of FIGS. 2 and 5, and the counters CNTa and CNTb are set. Reset.

  Next, in step S29 (conditional branch J6), it is determined whether or not the counter CNTc is 2 or more. If the result is No, the process returns to step S4.

  If the determination result in step S29 is Yes, it is determined in step S30 (conditional branch J7) whether the count value of the counter CNTup is greater than the count value of the counter CNTdn.

  If the determination result in step S30 is Yes, the ratio of the counter CNTup to the counter CNTdn (DIV = CNTup / CNTdn) is calculated in step S31.

  If the determination result in step S30 is No, a ratio of the counter CNTdn to the counter CNTup (DIV = CNTdn / CNTup) is calculated in step S32.

  Next, in step S33 (conditional branch J8), it is determined whether or not the counter ratio DIV is 2 or more (whether or not the number of processes for increasing the current set value I and the number of processes for decreasing is twice or less). judge.

  If the determination result in step S33 is Yes, in step S34, the current set value I is set to (Imax + Imin) / 2, the Imax update flag flagx and the Imin update flag flagy are reset, and the current increase / decrease coefficient K is If it is greater than 0.00003, K is multiplied by M (M = 0.5) to make it smaller, Imax and Imin are set to initial values 0, and counters CNTup and CNTdn are reset.

  If the determination result in step S33 is No, in step S35, flagx and flag are reset, Imax and Imin are set to the initial value 0, and the counters CNTup and CNTdn are reset. After executing steps S34 and S35, the process returns to step S4.

  In step S34, the convergence of the control current is accelerated by setting the current setting value I from Imax and Imin to an intermediate value. If the number of current increases and the number of decreases are significantly different, Imax and By taking an intermediate value of Imin, the control current value sometimes deviates. For this reason, in the present embodiment, an intermediate value is not taken when the number of times the current increases and decreases is more than twice as in steps S30 to S33 and S35.

  The CPU 120 periodically performs the constant voltage control of FIG. 2, converts the constant voltage control processing procedure into a flowchart, creates and records a control log including control path data in the flowchart executed during the constant voltage control. Means. This recorded data is called a control log.

  The control log can be taken out and viewed externally by communication means (LAN, serial communication, etc.) between the apparatus and the outside. One set of control log is created for each constant voltage control period. A set of control logs includes a time stamp (elapsed time t (ms) from the start of constant voltage control), a control path (which route in the algorithm has been passed), and various parameters at that time. The various parameters are I, Vdet, K, Imax, Imin, etc. in FIG.

  The algorithm is made into a flowchart as shown in FIG. 2, and numbers (J1 to J8, J10, J12 to J16 in FIG. 2) are assigned to the conditional branches. And “Division of branch destination (Yes / No)”.

  When the control path passes through each conditional branch, information on the conditional branch is added. The other information is recorded at the start of the constant voltage digital control cycle process (before passing through J2 (step S4) in FIG. 2).

  FIG. 6 shows a control log when the rechargeable nickel metal hydride battery is digitally controlled at a constant voltage of 1.2V. The initial value of the current output (current set value I) is 22.5 mA. The most important information is the J-Log or control path record. J02 (Y) in the J-Log column indicates that the conditional branch J2 has been passed to the Yes side. Similarly, J02 (N) indicates that the conditional branch J2 has been passed to the No side. By looking at this sequence of information, it is possible to know in detail in what order the route on the algorithm has been traced.

  In FIG. 6, for example, at time 58t, J2 → J4 → J5 → J6 → J7 → J8 is traced, and it is understood that the process of step S34 is performed because J8 is passed to the Yes side.

  For this reason, at the next time 59t, the current increase / decrease coefficient K is lowered to 0.0125, which is 1/2 (K = K * M (M = 0.5)), and Imax and Imin have initial values 0. .

  At time 60t, J2 → J4 → J5 → J12 → J15 → J14 is traced, and J14 is passed to the Yes side, so that it is understood that the processes of steps S24, S26, and S27 are performed.

  For this reason, at the next time 61t, 0.0123454, which is 1.0125 times as long as I is at time 60t (because processing of I = I * (1 + K) (K = 0.0125) is performed in step S24). Is set to

  Further, at time 61t, it can be seen that Imax is set to 0.23454 equal to the current set value I from the previous 0 by the process of step S27 after passing J14 to the Yes side.

  At time 61t, since the same control route as at time 60t was traced, I was set to 0.23747, which is 1.0125 times that at time 61t, compared to that at time 61t.

  At time 62t, J2 → J4 → J13 → J16 → J10 is traced, and J10 is passed to the Yes side, so that it is understood that the processing of steps S13 to S16 has been performed.

  Therefore, at the next time 63t, I is 0.9875 times that at time 62t (because the process of I = I * (1-K) (K = 0.0125) is performed in step S13). .02345.

  Further, at time 63t, it can be seen that Imin is set to 0.2345 equal to the current set value I from the previous 0 by the processing of step S16 after passing J10 to the Yes side.

  As described above, in the example of FIG. 6, it is understood that the constant voltage is controlled to approximately 1.2 V from time 50t to 79t, and the control path and various parameters I, Vdet, K, Imax, and Imin at each time are determined. I can know.

  As described above, according to the present embodiment, since the average of the detection voltage values for 100 obtained in the sampling cycle shorter than the execution cycle of the constant voltage digital control is used as the detection voltage value Vdet, Compared with the control method of Patent Document 1, fluctuation due to noise can be reduced, and the convergence of the control current can be accelerated.

  In the control method of Patent Document 1, since the sampling period of the AD converter coincides with the control period, the noise component of the circuit system including the AD converter appears in Vdet, and the increase / decrease in the current changes to prevent convergence.

  Since the convergence of the control current can be accelerated as described above, the initial value of the current increase / decrease coefficient K can be set to 0.025, which is significantly smaller than the conventional value. As a result, the current reduction rate at the start of constant voltage control can be reduced as compared with the conventional case, and an excessive voltage change can be reduced even for a sample (measurement target device) having a large internal resistance.

  Some samples have a property of repeating the current decrease many times, but in this case, the control current value calculated by the CPU 120 is reduced darkly. This occurs when digital arithmetic processing is performed with a single precision floating point. After the control current value has decreased, the control current value becomes a valid value even if the current value is increased. It takes time to become.

  In order to avoid this, in the present embodiment example, when the calculated control current value becomes less than the minimum value 1 lsb determined by the current range and the resolution of the DA converter, it is forcibly reversed in polarity and larger than the minimum value. A sufficiently small value for control (2 lsb in the embodiment) is set (step S17). If the current increase is determined thereafter, the original minimum polarity value 1 lsb is set at that time (step S20).

  Increase / decrease is repeated by the processing of steps S17 and S20, and the current value is stabilized, thereby eliminating the control delay caused by the calculation below the minimum resolution.

  According to the constant voltage digital control of the present embodiment example, since there is no hardware switching at the time of transition from constant current / constant power / constant resistance control to constant voltage control, electrical shock such as voltage overshoot is reduced. Suppress and make quick transitions.

  In addition, by oversampling the voltage value at a cycle shorter than the execution cycle of constant voltage digital control and performing an averaging process unique to digital control, the influence of disturbance elements such as high-frequency noise can be reduced. By increasing the processing speed of the AD converter, DA converter, and CPU, a higher effect can be obtained.

  Further, when the voltage value is detected and the current is increased / decreased by digital control, the necessary current for obtaining a constant voltage is roughly known, so that convergence is quick.

  According to the recording function of constant voltage digital control in the present embodiment, real-time and complicated operation process of constant voltage digital control can be left as a record of a route on the flowchart, and any problem in any part of the algorithm. This makes it easier to verify and correct whether there is any problem and improve the efficiency of algorithm and device development.

  In addition, it is possible to provide new user support in a form different from conventional ones, such as a specific presentation of the cause of the problem and the mechanism to the user of the charge / discharge function of the electrochemical measuring device.

  In addition, this invention is applicable not only to the circuit of FIG. 1 but other electrochemical measuring apparatuses.

DESCRIPTION OF SYMBOLS 101 ... Storage battery 102 ... Current detection resistor 103 ... Voltage detection circuit 104 ... Current detection circuit 105, 106 ... AD converter 107 ... DA converter 108, 111, 112 ... Resistance 109 ... Voltage / current control circuit 120 ... CPU
SW1, SW2 ... switch

Claims (6)

The charge / discharge voltage and charge / discharge current of the measurement target device in the electrochemical measurement device are detected and analog-to-digital converted by an AD converter. A computer that outputs a discharge voltage command signal;
An electrochemical measurement apparatus comprising: a voltage / current control circuit that controls a charge / discharge voltage and a charge / discharge current of the measurement target device by a signal obtained by digital-analog conversion of a command signal output from the computer by a DA converter. ,
The computer
Constant current / constant power / constant resistance control is started by outputting a current command signal, and when the voltage of the device to be measured reaches the target voltage, the current command signal is switched to a value corresponding to the target voltage Transition to control,
During the constant voltage control after the transition, the constant voltage control is performed according to the constant voltage control processing procedure based on the data obtained by averaging the detected voltages of the measurement target devices sampled at a cycle shorter than the execution cycle of the constant voltage control. Control means for controlling the current in the execution cycle of
In the control means, the detected voltage of the measurement target device exceeds a target voltage for constant voltage control, and a current setting value for performing constant voltage control is determined by a current range and resolution of the DA converter and AD converter. When the current set value is less than the minimum value, the current set value is set to a value opposite to the current current polarity and larger than the minimum value. Thereafter, the detected voltage of the measurement target device does not reach the target voltage and is constant. When the current setting value for voltage control is less than the minimum value determined by the resolution of the current range and the DA converter and AD converter, the current setting value is set to the current polarity before the reverse polarity is set . An electrochemical measurement apparatus comprising means for setting to a minimum value. The control means includes
When the detected voltage of the measurement target device exceeds the target voltage for constant voltage control, the current is decreased by the current increase / decrease coefficient, and when the detected voltage is less than the target voltage, the process for increasing the current by the current increase / decrease coefficient is defined. Current increasing / decreasing means for each execution period of voltage control;
2. The electrochemical measurement according to claim 1, further comprising: coefficient changing means for increasing the current increase / decrease coefficient when the process of increasing / decreasing the current is continuously executed a predetermined number of times or more. apparatus. The computer includes a means for creating and recording a control log including a flow chart of a constant voltage control processing procedure performed by the control means, and including control path data in the flowchart executed during the constant voltage control. The electrochemical measurement device according to claim 1 or 2 . The charge / discharge voltage and charge / discharge current of the measurement target device in the electrochemical measurement device are detected and analog-to-digital converted by an AD converter as input, and the charge / discharge current / power / resistance command signal and charge / discharge signal to the measurement target device are input. A computer that outputs a discharge voltage command signal;
Charging / discharging of an electrochemical measuring device comprising a voltage / current control circuit for controlling the charging / discharging voltage and charging / discharging current of the measurement target device by a signal obtained by digital-analog conversion of a command signal output from the computer by a DA converter A control method,
The computer control means comprises:
Constant current / constant power / constant resistance control is started by outputting a current command signal, and when the voltage of the device to be measured reaches the target voltage, the current command signal is switched to a value corresponding to the target voltage A transition to control;
After the transition, based on the data obtained by averaging the detected voltages of the measurement target devices sampled at a cycle shorter than the constant voltage control execution cycle, the current is output at the constant voltage control execution cycle according to the constant voltage control processing procedure. A constant voltage control step for controlling the
In the constant voltage control step, the detected voltage of the measurement target device exceeds a target voltage for constant voltage control, and the current setting value for performing constant voltage control is a current range and resolution of the DA converter and AD converter. When the current set value is less than the minimum value determined by the above, the current set value is set to a value opposite to the current current polarity and larger than the minimum value, and then the detection voltage of the measurement target device does not satisfy the target voltage. In addition, when the current set value for performing the constant voltage control becomes less than the minimum value determined by the resolution of the current range and the DA converter and AD converter, the current set value is set to the current before the reverse polarity is set. A charge / discharge control method for an electrochemical measurement apparatus, comprising a step of setting the polarity to a minimum value. The constant voltage control step includes:
When the detected voltage of the measurement target device exceeds the target voltage for constant voltage control, the current is decreased by the current increase / decrease coefficient, and when the detected voltage is less than the target voltage, the process for increasing the current by the current increase / decrease coefficient is defined. Current increase / decrease step for each execution period of voltage control;
5. The electrochemical measurement according to claim 4 , further comprising a coefficient changing step for increasing the current increase / decrease coefficient when the process of increasing / decreasing the current is continuously performed a predetermined number of times or more. Device charge / discharge control method. The control log creation / recording means of the computer creates a flowchart of a constant voltage control processing procedure performed by the control means, creates a control log including control path data in the flowchart executed during the constant voltage control, and records it 6. The charge / discharge control method for an electrochemical measurement apparatus according to claim 4, wherein a control log creating / recording step is performed.

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