JP2007021337A - Ion water generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion water generator suppressing deterioration of an electrode. <P>SOLUTION: The ion water generator includes an electrolyzing switching electric power source 2 generating a direct-current output in which an envelope becomes the pulsating flow of a half wave of a sine wave by switching the rectified voltage of a commercial alternating-current power source to supply to the electrodes 1a and 1b, electric current detection means for detecting an electric current flowing through the electrodes 1a and 1b, and switching control means for changing the peak value of the electric current of the direct-current output based on a detected electric current and pH setting. Thereby, since an electrolytic output electric current flows without making a substantial electric current off period and a change (di/dt) in electrolytic output electric current becomes small, the deterioration of the electrode can be suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ionic water generator, and more particularly to a power circuit thereof.

  Conventionally, in a power circuit of an ionic water generator, a commercial AC voltage is converted to a stable DC voltage, and duty control is performed by a switching element so that a desired electrolytic output is supplied to the electrode of the electrolytic cell. (For example, refer to Patent Document 1).

Japanese Patent Laying-Open No. 2004-25053 (paragraph [0020], FIG. 4)

In the conventional ionic water generator as described above, a sudden change occurs in the current flowing through the electrode by turning on / off the switching element, and the electrode deteriorates each time. As a result, the life of the electrode is shortened.
In view of the conventional problems as described above, an object of the present invention is to suppress electrode deterioration in an ionic water generator.

The ionic water generator of the present invention switches the rectification voltage of an electrolytic cell having an electrode and a commercial AC power source to generate a DC output in which the envelope becomes a sine wave half-wave pulsating flow, and this is applied to the electrode. A switching power supply for electrolysis to be supplied, current detection means for detecting a current flowing through the electrode, switching for changing the peak value of the current of the DC output based on the current detected by the current detection means and the pH setting And a control means.
In the ionic water generator configured as described above, the electrolytic output current flows without creating a substantial current off period by controlling the peak value of the direct current output that is a sine wave half-wave pulsating flow. Therefore, there is no steep rise / fall and the change in electrolytic output current (di / dt) is small compared to the duty control that creates the current on / off period.

In the ionic water generator, the electrolysis switching power supply is a non-capacitor input type circuit configuration in which the electrolytic capacitor is eliminated on the input side and the output side, and the response speed of the output control of the electrolysis switching power supply is It is preferable that it is sufficiently slower than the frequency of the commercial AC power supply.
In this case, since the circuit configuration excludes the electrolytic capacitor (first feature), a current flows through the rectifier during the entire period of the pulsating flow waveform (excluding the zero point). In addition, since the response speed of the output control of the electrolysis switching power supply is sufficiently slower than the frequency of the commercial AC power supply (second feature), the on-time of the switching is apparently constant during the half-wave period. Become. By providing these first and second features (AND condition), the current flowing through the primary side switching element of the electrolysis switching power supply is proportional to the input voltage (rectified output), and the sine wave half It becomes a repeated waveform. Therefore, the power factor is improved as compared with the circuit configuration of the capacitor input type.

  According to the ionic water generator of the present invention, the electrolytic output current flows by controlling the peak value of the direct current output, which is a sine wave half-wave pulsation, so that the change (di / dt) in the electrolytic output current is reduced, Deterioration of is suppressed.

Hereinafter, an ion water generator according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram mainly showing a power supply circuit of an ionic water generator. In the figure, a power supply circuit for supplying an electrolytic output to an electrolytic cell 1 having a pair of electrodes 1a and 1b includes an electrolysis switching power supply 2 for generating positive and negative polarity DC output from a rectified voltage of a commercial AC power supply, and a positive and negative polarity. Positive-side switching element 3 and negative-side switching element 4 provided in the output electric circuit. Electrolytic output is supplied to the electrodes 1 a and 1 b of the electrolytic cell 1 via the positive side switching element 3 or the negative side switching element 4. Thus, by configuring the power supply circuit that supplies the electrolysis output using the electrolysis switching power supply 2, the transformer 5 of the electrolysis switching power supply 2 is used at a frequency much higher than the commercial power supply frequency. Therefore, the transformer 5 can be made compact in size as compared with a transformer used at a commercial power supply frequency, and can be small, light, and low cost.

  In detail, first, the varistor 6 and the noise filter 7 are connected to the commercial AC power supply, thereby removing the surge and noise components included in the commercial AC power supply. A rectifier (bridge diode) 8 is connected to the noise filter 7, and the commercial AC voltage input thereto is full-wave rectified to become a pulsating voltage. The primary side winding of the transformer 5 is connected to the output side of the rectifier 8 through a resistor 9 and a switching element (MOSFET) 10 for electrolytic output in series. That is, the electrolysis switching power supply 2 has a non-capacitor input type circuit configuration in which an electrolytic capacitor is excluded on the input side.

  The transformer 5 transforms the primary side voltage to a desired voltage necessary for electrolytic output. An intermediate tap 5c is provided on the secondary side winding of the transformer 5, and the neutral wire N connected to the intermediate tap 5c is connected to the circuit ground and is connected to the electrode 1b via the resistor 11 (current detection means). It is connected to the. With respect to the neutral line N, outputs of opposite polarities are generated at the winding ends 5a and 5b on the secondary side of the transformer 5. A pair of diodes 12 and 13 are connected to the winding ends 5a and 5b in opposite directions. A positive side switching element 3 and a negative side switching element 4 (both MOSFETs) for polarity switching are connected to the diodes 12 and 13, respectively.

  An electrode 1a of the electrolytic cell 1 is connected to each of the switching elements 3 and 4 via a π-type filter 14 made of CLC. Although the π-type filter 14 has a smoothing function, it is a choke input type smoothing circuit, not a capacitor input type smoothing circuit. In the case of configuring a capacitor input type smoothing circuit, a pair of electrolytic capacitors are connected between the electric wires between the diodes 12 and 13 and the switching elements 3 and 4 and the neutral wire N. In this embodiment, such an electrolytic capacitor is not provided. That is, the electrolysis switching power supply 2 has a non-capacitor input type circuit configuration in which the electrolytic capacitor is excluded on the output side as well as the input side.

  Next, the configuration on the control side will be described. A zero cross detector 15 is connected to one of the output electric circuits of the rectifier 8, detects the zero cross of the pulsating voltage, and gives a zero cross detection signal to the control device 16. On the other hand, the polarity switching control unit 17 connected to the control device 16 alternately turns on the gates of the positive side switching element 3 and the negative side switching element 4 by the polarity switching signal from the control device 16 based on the zero cross detection signal. Give drive voltage. The control device 16 includes a microcomputer and its peripheral circuits.

  On the other hand, an electrolysis control unit 18 that controls the ON time of the switching element 10 by PWM control or frequency control is connected to the gate of the switching element 10. The electrolysis control unit 18 has a soft start function for gently raising the output by switching by externally attaching a capacitor 31 to the terminal CS. The electrolysis control unit 18 is connected to both ends of the resistor 9. The primary side current of the transformer 5 is monitored by a voltage signal, and if the drain current flowing through the switching element 10 increases, this can be limited. it can.

  When the user sets the pH (pH) of the ionic water, the control device 16 outputs a current control signal (for example, a voltage signal of 0 to 4.5 V) corresponding to the pH setting. This signal circuit is connected to the non-inverting input terminal of the operational amplifier 19 through a resistor 32. A capacitor 33 is connected between the non-inverting input terminal and GND.

On the other hand, a potential generated when the current flowing through the electrodes 1 a and 1 b flows through the resistor 11, that is, a current detection signal is input to the inverting input terminal of the operational amplifier 19 and also to the control device 16. The operational amplifier 19 differentially amplifies these inputs and drives the photocoupler 20 with the output. The output of the photocoupler 20 is given to the electrolysis controller 18, and PWM control is performed based on this. The op-amp 19 and the electrolysis control unit 18 are insulated from each other by the intervention of the photocoupler 20. A voltage detection signal indicating an output voltage of the π-type filter 14, that is, a voltage applied to the electrode 1 a is input to the control device 16.
The control device 16, the operational amplifier 19, the photocoupler 20, and the electrolysis control unit 18 constitute a switching control unit for the switching element 10.

  The output circuit of the rectifier 8 is connected to a diode 21 for preventing voltage wraparound, a thermistor 22 for preventing inrush current, and a smoothing electrolytic capacitor 23, and the voltage of the electrolytic capacitor 23 is input to the control switching power supply 24. The Therefore, the control switching power supply 24 has a capacitor input type input circuit configuration. The DC12V output circuit and GND of the control switching power supply 24 are connected to the control device 16. In addition, a DC5V output circuit via the dropper power supply 25 is connected to the control device 16. The coil 26c of the relay 26 receives an electromagnetic valve on / off signal from the control device 16 and enters an excited / de-energized state. A solenoid valve 27 is connected to the DC12V output circuit of the control switching power supply 24 and GND via a contact 26a of the relay 26, respectively. By the operation / operation stop of the electromagnetic valve 27, the water flow for generating ionic water is turned on / off.

In the ion water generator configured as described above, the commercial AC voltage V _in ((a) of FIG. 2) is full-wave rectified by the rectifier 8, and the pulsating voltage V _P ((c) of FIG. 2) Become. Since there is no electrolytic capacitor on the input side of the electrode for the switching power supply 2, as described above, the pulsating voltage V _P is not smooth. The pulsating voltage _{V P} is the switching element 10 which is controlled by the electrolysis controller 18 is switched to a high speed (30~45kHz), the transformer 5 is transformed to a predetermined voltage. Assuming now that the positive side switching element 3 is on and the negative side switching element 4 is off, current flows from the diode 12 to the switching element 3 on the secondary side of the transformer 5 so that one electrode 1a is + and the other is The electrode 1b has a negative polarity. When a current flows through the electrodes 1a and 1b, the current detection signal is negatively fed back to the operational amplifier 19, and current control is performed so that the current flowing through the electrodes 1a and 1b converges to a current corresponding to the current control signal. Thus, ion water having a pH corresponding to the current control signal is generated.

Further, in order to prevent impurities from adhering to the electrodes 1a and 1b, the ON / OFF states of the switching elements 3 and 4 are periodically switched alternately by the control device 16 and the polarity switching control unit 17. When the positive side switching element 3 is turned off and the negative side switching element 4 is turned on, a current flows from the negative side switching element 4 to the diode 13 through the electrolytic cell 1 from the neutral line N on the secondary side of the transformer 5, The electrode 1b has a positive polarity and the electrode 1a has a negative polarity. Such polarity switching is performed, for example, at a cycle of 1 second. Further, due to duty control from the control device 16 to the polarity switching control unit 17, for example, 95% of one cycle has a polarity in which current flows in a direction in which selected ionic water (usually alkaline ionic water) is generated, The remaining 5% has the opposite polarity. Polarity switching in the polarity switching controller 17, based on the zero-cross detection signal from zero-cross detection unit 15 is performed at the zero point of the voltage V _P.

In the above-mentioned switching operation by the switching device 10, current I _d flowing through the switching element 10 becomes a narrow pulse intermittent waveform width, substantial waveform becomes the envelope. Here, if the on-time of the switching element 10 is T _on , the inductance of the primary winding of the transformer 5 is L, and the resistance value of the resistor 9 is ignored, the current I _d flowing through the switching element 10 is
I _d = V _P × (T _on / L). . . (1)
It becomes.

The response speed of the electrolysis control unit 18 is set sufficiently slower than the commercial frequency (50 or 60 Hz). “Sufficiently slow” means a frequency of 1 to 10 Hz, preferably several Hz. Thus, for example, in the period of the pulsating flow half wave of 10ms in the case of 50 Hz, apparently _{T on} it is constant. That is, by the slow response speed, without response electrolyte control section 18 during a period of 10 ms, T _on is constant. Thus, _{T on} and L in the formula (1) is constant, _{I d} is proportional to _{V P.} Thus, I _d is similar to the V _P, the pulsating waveform repeating sinusoidal half wave (in Figure 2 (d)).

Further, as described above, the power factor is improved by the non-capacitor input type circuit configuration on both the input side and the output side of the electrolysis switching power supply 2.
If a capacitor input type smoothing circuit is configured, smoothing is performed using charging and discharging of the capacitor, so that the period during which current flows through the rectifier 8 (conduction angle) is small and the power factor is low. Become. For example, in an ion water generator that requires an output of 200 W (100 V), when the capacitor input type is used, assuming that the power factor is 0.5 and the efficiency is 80%, the input current is 200 / ( 0.8 × 0.5 × 100), 5A is obtained.
On the other hand, as described above, according to the non-capacitor input type circuit configuration excluding the electrolytic capacitor, current flows through the rectifier 8 during the entire period of the pulsating waveform (excluding the zero point), and the power factor is increased. Improved. In the experiment, the power factor was improved to almost 1 (0.99). Therefore, the input current is halved (2.5 A).

Incidentally current I _P flowing into the control switching power supply 24, the conduction angle of the rectifier 8 is reduced by the presence of the electrolytic capacitor 23, the current I _P only one time in the [pi [rad] periods for pulsating current voltage V _P It does not flow ((e) of FIG. 2). As a result, the input current _{I in} of the whole ion water generator has a waveform obtained by superimposing _{I P} to _{I d} (in Figure 2 (b)).

FIG. 3 is a time chart from when the commercial AC power is turned on until a predetermined electrolytic output current flows. In the figure, when the commercial AC power on the input voltage pulsating current voltage _{V P} of the switching power supply 2 is turned on at time t1, DC5V and DC12V rises until time t2. The zero cross detector 15 detects a zero cross of the input voltage and inputs a detection signal (pulse train) to the control device 16. After that, when the electromagnetic valve 27 is opened by the ion water generation start operation and the water flow is detected at time t3, a current control signal (corresponding to pH setting) is obtained at time t4, which is the timing of the zero crossing immediately thereafter. It changes from 0 to 2.5V, for example. Thereby, an electrolytic output current flows from the switching power supply 2 to the electrolytic cell 1.

  Here, the crest value gradually increases with the passage of time from t4 by the above-described soft start function of the electrolysis control unit 18. The electrolytic output current is negatively fed back to the operational amplifier 19 as a “current detection signal”, and after a soft start end time t5, a constant electrolytic output current corresponding to the current control signal 2.5V corresponding to the pH setting is supplied to the electrolytic cell 1. Flowing into. In this way, the electrolytic output current flows without creating a substantial current off period by controlling the peak value of the direct current output, which is a sine wave half-wave pulsation. Therefore, there is no steep rise / fall and the change in electrolytic output current (di / dt) is small compared to the duty control that creates the current on / off period. Thereby, deterioration of the electrodes 1a and 1b is suppressed, and the lifetime is extended. Also, noise and switching loss are reduced.

  FIG. 4 is a time chart regarding pH setting change during electrolysis. When the current control signal changes from 2.5V to 4.5V at time t6, the electrolysis output current gradually increases due to the soft start function of the electrolysis control unit 18, and a peak value corresponding to 4.5V with a time delay. To reach. When the current control signal changes from 4.5 V to 1 V at time t7, the electrolytic output current gradually decreases due to the action of the capacitor 33 and the resistor 32, and reaches a peak value equivalent to 1 V with a time delay. In this way, the increase and decrease of the crest value is moderated, which further contributes to extending the life of the electrodes 1a and 1b.

In the above embodiment, polarity switching is performed on the secondary side of the transformer 5, but this is an example, and polarity switching is not necessarily required.
In the above embodiment, the capacitor 33 is provided on the input side of the operational amplifier 19, but such a capacitor may be provided in the photocoupler 20 or the electrolysis control unit 18.

It is a circuit diagram mainly having a power supply circuit of the ion water generator by one Embodiment of this invention. It is a figure which shows the waveform of the voltage or electric current of each part on the circuit shown in FIG. It is a time chart from a commercial alternating current power supply until a predetermined electrolytic output current flows. It is a time chart regarding pH setting change during electrolysis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyzer 1a, 1b Electrode 2 Switching power supply 8 Rectifier 11 Resistance (current detection means)
16 Control Device 18 Electrolytic Control Unit 19 Op Amp 20 Photocoupler

Claims (2)

An electrolytic cell having electrodes;
Switching the rectified voltage of the commercial AC power supply, generating a DC output in which the envelope is a sine wave half-wave pulsating current, and supplying this to the electrode;
Current detection means for detecting a current flowing through the electrode;
An ionic water generator comprising: a switching control means for changing a peak value of the current of the DC output based on a current detected by the current detection means and a pH setting.   The electrolysis switching power supply has a non-capacitor input type circuit configuration in which electrolytic capacitors are excluded on the input side and the output side, and the response speed of output control of the electrolysis switching power supply is the frequency of the commercial AC power supply. The ionic water generator according to claim 1, which is sufficiently slower.

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