JP2009004260A - Ion generating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion generating device preventing such accidents as firing or burnout by detecting deterioration of insulation of a discharge electrode and either notifying of it or protecting an ion generating device main body and its peripheries. <P>SOLUTION: The ion generating device 1 is provided with a high-voltage power supply circuit 3 outputting high voltage to be impressed on a discharge needle 2 constituting a discharge electrode and a counter electrode 15, a micro discharge detecting means generating detection signals in accordance with micro discharge generated separately from corona discharge when high voltage is impressed on the discharge electrode from the high-voltage power supply circuit, and a micro discharge detection device 30 outputting alarm signals when it detects the micro discharge based on detection signals from the micro discharge detecting means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ion generator that generates positive and negative air ions in the atmosphere.

  2. Description of the Related Art Conventionally, an ion generator that generates positive and negative air ions in the atmosphere by applying a high voltage to a discharge electrode including a needle electrode (discharge needle) and a counter electrode to generate corona discharge is known. . In this type of ion generation apparatus, the high voltage may be a DC voltage or an AC voltage, but when an AC high voltage is used, positive and negative voltages are alternately applied to the needle electrodes.

  Here, when a positive voltage is applied to the needle electrode, among the positive and negative air ions to be generated, the negative ion moves toward the needle electrode, and the positive ion moves toward the counter electrode. At this time, most of the positive ions are captured by the counter electrode, but some of the positive ions are released to the outside beyond the counter electrode. On the other hand, when a negative voltage is applied to the needle electrode, the opposite phenomenon occurs when a positive voltage is applied, and most of the generated negative and positive air ions face each other. The positive ions are trapped by the electrodes, and some positive ions are released to the outside beyond the counter electrode.

  According to such an ion generation device, when an alternating voltage is used, positive ions and negative ions can be generated in almost equal amounts, so the positive and negative air ions generated as described above are directed to the charged body. Thus, even if the charged body is positively or negatively charged, the charge can be neutralized and the charge can be removed satisfactorily.

  FIG. 9 shows an example of a conventional ion generator. This includes a high-voltage power supply circuit 41, a plurality of discharge needles 43 connected to the high-voltage power supply circuit 41 via a high-voltage cable 42, and a counter electrode 44 provided opposite to each discharge needle 43 and grounded. The discharge needle 43 and the counter electrode 44 constitute a discharge electrode. The discharge needle 43 is connected to the high-voltage cable 42 through a core material 46 made of a conductive material provided in the inside of a support member 45 made of an insulating material, and a tip portion projects from the support member 45 to the outside. Are arranged in a shape. The counter electrode 44 is made of a rod-shaped conductor and is sandwiched between flange members 47, 47 made of an insulating material provided at both ends of the support member 45, and is installed in parallel with the plurality of discharge needles 43 arranged in a straight line. Has been.

  In such an ion generator, the discharge electrode is supported by a support member made of an insulating material, and dust and the like are carbonized by discharge generated between the discharge electrode and the counter electrode, particularly in the vicinity of the discharge needle, and becomes carbon. In some cases, the surface of the insulating support member may adhere to the surface, and as it accumulates, the insulation, that is, the electrical resistance value of the discharge electrode decreases. If the operation is continued without removing such deposits or other maintenance, the resistance value further decreases, eventually an excessive current flows from the discharge needle to the ground side, and the ion generation measure main body and its surroundings. It will cause accidents such as ignition and burning. The conventional ion generating apparatus is designed to be safe by shutting off the power supply when such an accident occurs.

  However, shutting off the power supply when an accident such as ignition due to a decrease in the insulating properties of the discharge electrode occurs is a post-procedure and may lead to a more serious accident. Therefore, it has been desired to detect an insulation deterioration of the discharge electrode before an accident due to an excessive current as described above to prevent an accident such as ignition or damage.

  In view of such a situation, the present invention provides an ion generation device that detects a decrease in insulating properties of a discharge electrode, notifies it or protects a power supply circuit and the like, and does not cause an accident such as ignition or burning. With the goal.

  When the insulating property (resistance value) of the discharge electrode is lowered to a certain value or less, the present inventors have found a slight discharge phenomenon different from the original corona discharge when a high voltage is applied to the discharge electrode. By detecting the occurrence of this (hereinafter referred to as “micro discharge” or “PD”) and detecting this, it is possible to prevent accidents and protect the power supply device and the like.

  That is, the present invention outputs a high voltage to be applied to the discharge electrode in an ion generator that generates a corona discharge from the discharge electrode by applying a high voltage to the discharge electrode and generates air ions by the corona discharge. A high-voltage power supply circuit, a micro-discharge detection means for generating a detection signal corresponding to a micro-discharge generated separately from the corona discharge when a high voltage is applied from the high-voltage power circuit to the discharge electrode, and the micro-discharge detection And a fine discharge determining means for outputting an alarm signal when it is determined that the discharge is a slight discharge based on a detection signal from the means.

  According to the ion generating apparatus of the present invention, when a high voltage is applied to the discharge electrode from the high-voltage power supply circuit, the fine discharge is determined by the detection signal corresponding to the fine discharge generated separately from the corona discharge, and an alarm signal is generated. . Thereby, it is possible to prevent an accident such as ignition or damage by detecting a decrease in the insulating property of the discharge electrode and notifying it.

  In a preferred embodiment of the present invention, the fine discharge determination means outputs a signal for interrupting power supply to the high-voltage power supply circuit together with the alarm signal when it is determined that the discharge is fine. Thereby, it is possible to prevent an excessive return current from flowing to the ground side.

  Further, the fine discharge detection means may be configured such that a voltage generated by a current flowing through a resistor connected to the ground electrode side of the discharge electrode from the output portion of the high-voltage power supply circuit as the detection signal or from the high-voltage power supply circuit. A voltage generated by a current flowing through an output portion connected to the needle electrode of the discharge electrode is input to the fine discharge determination means as the detection signal.

  The high-voltage power supply circuit includes a winding transformer having a primary winding and a secondary winding, and a pulse train output circuit that outputs a plurality of pulse train voltages applied to the primary winding. The detection means uses the voltage generated by the current flowing through the resistor connected to the ground terminal of the pulse train output circuit or the voltage generated by the current flowing through the constant voltage source side of the pulse train output circuit as the detection signal, It is comprised so that it may input into a determination means.

  Alternatively, the high-voltage power circuit includes a winding transformer that boosts a voltage applied to the primary side to generate a high voltage on the secondary side, and an AC power source that applies an AC voltage to the primary side of the winding transformer, or An oscillation circuit that generates an AC high frequency voltage on the primary side of the winding transformer by applying a DC voltage may be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, an ion generator 1 according to an embodiment is arranged near a discharge needle 2 supported by a support member (not shown) made of an insulator as in the prior art, and near the tip of the discharge needle 2 and A discharge electrode composed of a grounded counter electrode 15, a high-voltage power supply circuit 3 that outputs a high voltage applied to the discharge electrode, and a control circuit that controls on / off of switch elements of the high-voltage power supply circuit 3 as will be described later 4 is provided.

  The high-voltage power supply circuit 3 includes a winding transformer 5 having a primary winding 5a and a secondary winding 5b, and a pulse train output circuit 6 that outputs a plurality of pulse train voltages applied to the primary winding 5a. One end of the secondary winding 5 b of the winding transformer 5 is connected to the discharge needle 2, and the other end is connected to the counter electrode 15.

  In FIG. 1, one discharge needle 2 and the counter electrode 15 are shown. However, as shown in the conventional example (FIG. 6), a plurality of discharge needles 2 arranged with respect to one counter electrode are high-voltage cables. The structure connected to the end of the secondary winding 5b via the above may be sufficient.

  In the present embodiment, the other end of the secondary winding 5b connected to the counter electrode 15 is grounded via a resistor (resistance value may be constant or variable) 16 to detect a slight discharge as will be described later. Has been.

  The pulse train output circuit 6 is a so-called H-bridge type circuit, and includes a first series circuit 11 formed by connecting a first switch element 7 and a second switch element 8 in series, a third switch element 9, and A second series circuit 12 formed by connecting the fourth switch elements 10 in series and a DC power source 14 for applying a DC voltage to a parallel circuit 13 formed by connecting these series circuits 11 and 12 in parallel are provided. .

  Each switch element 7-10 is a semiconductor switch element. In the present embodiment, the first and third switch elements 7 and 9 are configured by p-channel FETs, and the second and fourth switch elements 8 and 10 are configured by n-channel FETs. Each of the switch elements 7 to 10 has a gate serving as a control signal input unit connected to the control circuit 4, and the switch elements 7 to 10 according to a control signal (ON / OFF signal) supplied from the control circuit 4. 10 to ON / OFF (conduction / interruption between source and drain) is controlled.

  In addition, you may comprise each switch element 7-10 with a switching transistor. Or you may mix FET and a switching transistor. For example, the switch elements 7 and 9 among the switch elements 7 to 10 may be configured by FETs, and the switch elements 8 and 10 may be configured by switching transistors.

  One end of the first series circuit 11 including the first and second switch elements 7 and 8 on the switch element 7 side (source of the switch element 7), and a second including the third and fourth switch elements 9 and 10. One end of the series circuit 12 on the switch element 9 side (source of the switch element 9) is connected, and the other end of the first series circuit 11 on the switch element 8 side (source of the switch element 8) and the second The other end of the series circuit 12 on the switch element 10 side (source of the switch element 10) is connected. Thereby, the first series circuit 11 and the second series circuit 12 are connected in parallel to constitute the parallel circuit 13.

  One end of the parallel circuit 13 on the switch elements 7 and 9 side is connected to the positive electrode of a DC power supply 14 that outputs a DC voltage (for example, 24 V), and the other end of the parallel circuit 13 on the switch elements 8 and 10 side is grounded. ing. Note that the negative electrode of the DC power supply 14 is grounded and is electrically connected to the other end of the parallel circuit 13 on the switch elements 8 and 10 side. As a result, a DC voltage is applied from the DC power supply 14 to the parallel circuit 13.

  A connection point 11 a between both switch elements 7, 8 of the first series circuit 11 and a connection point 12 a between both switch elements 9, 10 of the second series circuit 12 are a pair of output portions of the pulse train output circuit 6. Both ends of the primary winding 5a of the winding transformer 5 are connected to the output portions 11a and 12a, respectively.

  In this embodiment, regarding the voltage applied to the primary winding 5a of the winding transformer 5 from the output units 11a and 12a of the pulse train output circuit 6, one output unit 11a side is positive with respect to the other output unit 12a side. The polarity of the potential voltage is defined as positive polarity, and the polarity of the voltage at which the other output portion 12a side is positive with respect to the one output portion 11a side is defined as negative polarity voltage. In this case, in this embodiment, when a positive voltage is applied to the primary winding 5a, a high voltage is generated in the secondary winding 5b so that the discharge electrode 2 side is positive, and the primary winding 5a has a negative polarity. Is applied, a high voltage is generated in the secondary winding 5b so that the discharge electrode 2 side is negative.

  The control circuit 4 includes a CPU, a RAM, a ROM, an interface circuit, etc. (not shown). In the present embodiment, the control circuit 4 outputs an on / off signal (rectangular wave signal) to the gates of the switch elements 7 to 10 based on a program stored in advance in the ROM or already input data from the outside. Then, on / off control of the switch elements 7 to 10 is performed by the on / off signal.

  Next, the basic operation of the high-voltage power supply circuit 3 will be described with reference to FIG. FIG. 2 is a graph illustrating the relationship between the on / off control of each of the switch elements 7 to 10 and the voltage (high voltage) generated in the secondary winding 5b of the winding transformer 5 accordingly.

  In the present embodiment, when a positive high voltage is generated in the secondary winding 5b of the winding transformer 5, the first switch element 7 is turned on, as illustrated by the period TP in FIG. With the switch element 8 and the third switch element 9 turned off, the fourth switch element 10 is repeatedly turned on and off at a relatively high speed. At this time, only when the fourth switch element 10 is on, it has a voltage value substantially equal to the output voltage of the DC power supply 14 and the fourth switch element 10 is continuous. A positive-polarity pulse voltage (rectangular wave-shaped pulse voltage) having a width substantially equal to the on-time (on-time) is generated between the output portions 11a and 12a, and this is the primary winding of the winding transformer 5 Applied to 5a. Accordingly, by repeating ON / OFF of the fourth switch element 10 in the period TP in the figure, a voltage having the same waveform as the ON / OFF waveform 20, that is, a plurality of positive pulse voltages are time-sequentially. The arranged positive side pulse train is applied to the primary winding 5a from the output portions 11a and 12a.

  In this case, within the period TP (hereinafter, referred to as the positive pulse train output period TP), the timing at which the fourth switch element 10 is turned on (the generation timing of each pulse voltage in the positive pulse train), or the fourth switch element 10. By appropriately setting the ON time (the width of each pulse voltage of the positive-side pulse train), the secondary winding 5b of the winding transformer 5 has a positive polarity as shown in the lowermost graph of FIG. The pulse-like (convex-shaped) high voltage VP can be generated.

  More specifically, in the present embodiment, the on / off waveform 20 of the fourth switch element 10 in the positive pulse train output period TP is composed of a first half on / off waveform 20a and a second half on / off waveform 20b. Of the positive-side pulse train in the positive-side pulse train output period TP, the portion corresponding to the first half-side on / off waveform 20a (hereinafter referred to as the positive-side pulse train first half) includes the generation timing of the positive high voltage VP, A peak value P (peak value) of the active high voltage VP. That is, since the start timing of the first half of the positive pulse train (start timing of the first on / off waveform 20a) is the rising timing of the positive high voltage VP, the start timing of the first half of the positive pulse train is changed. Thus, the generation timing of the positive high voltage can be changed as illustrated by adding the reference sign VP ′ in FIG. Also, by changing the width of any pulse voltage in the first half of the positive pulse train, and changing the total width of each pulse voltage in the positive pulse train (the total on time in the first half on / off waveform 20a). In the range where magnetic flux saturation of the core of the winding transformer 5 does not occur, the peak value of the positive high voltage can be changed as shown in FIG. In this case, basically, the peak value of the positive high voltage increases as the total sum of the pulse voltage widths of the positive pulse train increases.

  In the positive pulse train, the portion corresponding to the second half on / off waveform 20b (hereinafter referred to as the positive pulse train second half) immediately after the positive high voltage VP drops from the peak value to 0 [V]. The secondary winding 5b has a function of preventing a negative counter electromotive voltage from being generated. That is, in the process in which the positive high voltage VP decreases from the peak value to 0 [V], or in the vicinity of 0 [V], one or a plurality of positive pulse voltages are output from the output windings 11a and 12a to the primary winding. By applying the voltage to 5a, it is possible to prevent a negative counter electromotive voltage from being generated in the secondary winding 5b.

  Further, in the present embodiment, when a negative high voltage is generated in the secondary winding 5b of the winding transformer 5, the third switch element 9 is turned on, as exemplified by the period TN in the figure. With the first switch element 7 and the fourth switch element 10 turned off, the second switch element 8 is repeatedly turned on and off at a relatively high speed. At this time, only when the second switch element 8 is on, it has a voltage value almost equal to the output voltage of the DC power supply 14 and the on-time of the second switch element 8. A negative pulse voltage (rectangular wave pulse voltage) having substantially the same width as that is generated between the output portions 11 a and 12 a and applied to the primary winding 5 a of the winding transformer 5. Accordingly, by repeating ON / OFF of the second switch element 8 in the period TN in the figure, a voltage having a waveform equivalent to the ON / OFF waveform 21, that is, a negative electrode side composed of a plurality of negative pulse voltages. A pulse train is applied to the primary winding 5a from the output portions 11a and 12a.

  In this case, within the period TN (hereinafter referred to as the negative-side pulse train output period TN), the timing at which the second switch element 8 is turned on (the generation timing of each pulse voltage in the negative-side pulse train), or the second switch element 8 By appropriately setting the ON time (the width of each pulse voltage of the negative pulse train), the secondary winding 5b of the winding transformer 5 has a negative polarity as shown in the lowermost graph of FIG. A pulsed (convex) high voltage VN can be generated.

  More specifically, in the present embodiment, as in the case of the positive pulse train output period TP, the on / off waveform 21 of the second switch element 8 in the negative pulse train output period TN is the first half on / off waveform 21a. The second half side ON / OFF waveform 21b. Of the negative-side pulse train in the negative-side pulse train output period TN, the portion corresponding to the first half-side on / off waveform 21a (hereinafter referred to as the negative-side pulse train first half) includes the generation timing of the negative high voltage VN, And a peak value N (peak value) of the high voltage VN. That is, since the start timing of the first half of the negative pulse train is the rising timing of the negative high voltage VN, the reference timing VN ′ is added to FIG. 2 by changing the start timing of the first half of the negative pulse train. As illustrated, the generation timing of the negative high voltage can be changed. Also, the width of one or more pulse voltages in the first half of the negative-side pulse train is changed, and the sum of the widths of the pulse voltages in the negative-side pulse train (total on-time in the first half-side on / off waveform 21a) is changed. As a result, the peak value of the negative high voltage can be changed within a range in which the magnetic flux saturation of the core of the winding transformer 5 does not occur, as shown in FIG. In this case, basically, as the sum of the widths of the pulse voltages of the negative pulse train increases, the magnitude (absolute value) of the peak value of the negative high voltage increases.

  In the ion generator 1 of this embodiment, the control circuit 4 turns on the first switch element 7 and turns off the second switch element 8 and the third switch element 9 as in the positive pulse train output period TP. On the other hand, the positive-side pulse train output control for performing on / off control of the switch elements 7 to 10 so as to repeat the on-off of the fourth switch element 10 and the negative-side pulse train output period TN are the third On / off control of each of the switch elements 7 to 10 is repeated so that the second switch element 8 is repeatedly turned on / off while the switch element 9 is turned on and the first switch element 7 and the fourth switch element 10 are turned off. The negative-side pulse train output control to be performed is alternately executed at the same cycle.

  In the present embodiment, the first switch element 7 and the third switch element 9 are turned on as shown in FIG. 2 in the period between the positive pulse train output period TP and the negative pulse train output period TN. At the same time, the second switch element 8 and the fourth switch element 10 are controlled to be turned off.

  FIG. 3 shows an example of a waveform of a high voltage (AC high voltage) generated in the secondary winding 5b of the winding transformer 5 when the on / off control of the switch elements 8 to 10 is performed as described above. It is a graph. As shown in the figure, a positive high voltage VP and a negative high voltage VN are alternately generated in the secondary winding 5b with a constant period Ta. The high voltage generated in this way is applied to the discharge electrode 2 from the secondary winding 5b to the counter electrode 15.

  In this case, in this embodiment, the period Ta is a predetermined constant period, and is, for example, 5 milliseconds (200 Hz in terms of frequency). Then, the control circuit 4 includes the start timing of the positive pulse train output control (the rising timing of the positive high voltage VP) in each cycle Ta of the positive high voltage VP and the start timing of the negative pulse train output control ( Data defining a time interval Tb (hereinafter, referred to as a positive / negative time Tb) with respect to the rising timing of the negative high voltage VN), and an ON / OFF waveform 20 of the fourth switch element 10 in the positive pulse train output control The data defining the pattern, the data defining the pattern of the on / off waveform 21 of the second switch element 8 in the negative pulse train output control, and the like can be input from the outside.

  These data are, for example, data indicating the on / off states of the switch elements 7 to 10 at predetermined intervals (for example, 20 μs) in the period of one cycle Ta of the positive high voltage VP (hereinafter referred to as switch on / off). Off-data).

  Then, the control circuit 4 alternately executes positive side pulse train output control and negative side pulse train output control based on the inputted switch on / off data, and controls on / off of the switch elements 7 to 10. . In this case, the control circuit 4 performs on / off control of the switch elements 7 to 10 according to the switch on / off data for each predetermined interval in each cycle Ta.

  Supplementally, in the present embodiment, the third switch element 9 is maintained in the OFF state in the positive-side pulse train output period TP. However, when the fourth switch element 10 is controlled to be in the ON state, the third switch element 9 is maintained. 9 may be controlled to the off state, and the third switch element 9 may be controlled to the on state when the fourth switch element 10 is controlled to the off state. In other words, the third switch element 9 may be controlled to be turned off and on contrary to the fourth switch element 10 being turned on and off. Similarly, in the negative side pulse train output period TN, when the second switch element 8 is controlled to be turned on, the first switch element 7 is controlled to be turned off, and when the second switch element 8 is controlled to be turned off. The first switch element 7 may be controlled to be on. In other words, the first switch element 7 may be controlled to be turned off and on in reverse to the second switch element 8 being turned on and off.

  By doing in this way, especially when the off time immediately after the fourth switch element 10 is turned on or the off time immediately after the second switch element 8 is turned on becomes relatively long. It is possible to prevent the current flowing through the primary winding 5a of the line transformer 5 from changing abruptly, and to smoothly change the positive high voltage VP and the negative high voltage VN.

  In the present embodiment, the fourth switch element 10 in the positive pulse train output period TP is controlled to be either on or off at every predetermined time interval. You may make it control the duty which is a ratio of the time when the 4th switch element 10 turns on. In this case, the peak value of the positive high voltage can be adjusted by adjusting the duty in the waveform of the first half of the ON / OFF waveform of the fourth switch element 10 in the positive pulse train output period TP. it can. Further, by adjusting the duty in the waveform in the latter half, it is possible to prevent a negative counter electromotive voltage from occurring immediately after the positive high voltage drops to 0 [V]. Similarly, in the ON / OFF control of the second switch element 8 in the negative pulse train output period TN, the duty that is the ratio of the time during which the second switch element 8 is turned on within a predetermined time interval is controlled. It may be. In this case, the peak value of the negative high voltage can be adjusted by adjusting the duty in the waveform of the first half of the ON / OFF waveform of the second switch element 8 in the negative pulse train output period TN. it can. Further, by adjusting the duty in the waveform of the latter half, it is possible to prevent the occurrence of a positive counter electromotive voltage immediately after the negative high voltage has dropped to 0 [V].

  In the ion generator 1 configured as described above, when the positive high voltage VP is applied to the discharge needle 2 from the secondary winding 5b of the winding transformer 5, it is generated near the tip of the discharge needle 2. The positive air ions are generated by the corona discharge. Then, the generated positive air ions are released in a direction away from the vicinity of the tip of the discharge needle 2. Further, when the negative high voltage VN of the discharge needle 2 is applied from the secondary winding 5b, negative air ions are generated by corona discharge generated near the tip of the discharge needle 2. Then, the generated negative air ions are released in a direction away from the vicinity of the tip of the discharge needle 2.

  The above is the configuration and basic operation of the ion generator 1 of the present embodiment. The ion generator 1 may be provided with means such as a fan for generating an air flow for carrying air ions in the vicinity of the discharge needle 2.

  Next, in the present embodiment, as described above, the following PD detection is performed in order to detect the slight discharge generated due to the decrease in insulation of the discharge electrode and perform processing such as power shut-off and alarm display. Equipment.

  That is, in the embodiment of FIG. 1, the fine discharge detection means includes a resistor 16 connected to the other end of the secondary winding 5 b of the winding transformer 5 of FIG. 1, and the PD detection device 30 shown in FIG. A high-pass filter 31 for inputting a PD detection signal taken out from one end of the resistor 16; a one-shot timer 32 for generating a square wave having a predetermined time width (for example, 20 μsec) by inputting the output (high-frequency signal); And a microcomputer 33 for inputting a square wave signal output from the timer and outputting a predetermined alarm signal when it is determined that a slight discharge has occurred. The PD detection device 30 constitutes a fine discharge determination means for determining a fine discharge based on the PD detection signal and outputting an alarm or other necessary signal.

  FIG. 5 shows a circuit configuration of the high-pass filter 31 and the one-shot timer 32 in the PD detection device 30.

  The high-pass filter 31 includes a predetermined capacitor C1 connected to an input terminal to which a PD detection signal is input and a resistor R1 to which a DC voltage Vcc is applied, and a high frequency having a frequency (range) determined by the capacitance and the resistance value. Output a signal.

  The one-shot timer 32 has a base connected to the input end, a transistor Q1 to which the DC voltage Vcc is applied on the emitter side, a resistor R2 connected between the collector side and the ground, and one end on the collector side of the transistor Q1. A resistor R3 having a base connected to the other end of the resistor R3, a emitter Q2 having a grounded emitter, a resistor R4 having a collector connected to the DC voltage Vcc, and a transistor Q2 and a resistor R4. A capacitor C2 connected between the connection point and the ground, and two inverters I1 and I2 for sequentially inverting the voltage signal at the connection point between the resistor R4 and the capacitor C2 are provided.

  Next, the fine discharge detection operation by the PD detection device 30 will be described.

  In the configuration of FIG. 1, when a high voltage output from the secondary side of the winding transformer 5 is applied between the discharge needle 2 constituting the discharge electrode and the counter electrode 15 to generate corona discharge, Thus, a slight discharge is generated due to a decrease in the insulating properties of the discharge electrode. In that case, a current due to a slight discharge flows from the secondary winding 2 b of the winding transformer 5 through the resistor 16. At this time, the voltage detected at one end of the resistor 16 is a high-frequency signal mainly having a pulse width of 2 to 10 nsec (nanoseconds). As shown in FIG. A PD detection signal superimposed on the peak waveform of the alternating high voltage (FIG. 3) generated in the next winding 5b is input to the input portion of the high-pass filter 31 shown in FIG.

  In the high pass filter 31, the PD detection signal is generated as a high frequency signal as shown in FIG. 6B by the filter composed of R1 and C1.

  This high-frequency signal is input to the one-shot timer 32, and is shaped into a square wave having a time width (for example, 20 μsec) that can be detected by the microcomputer (CPU) 33, as shown in FIG. 6C.

  Specifically, in the one-shot timer 32 shown in FIG. 5, when the signal (B) input thereto is at a high level (H), the transistor Q1 is turned off, so that the voltage of the resistor R2 is low and the resistor R3 is low. Since the base voltage of the transistor Q2 connected through the transistor is low, the transistor Q2 is also turned off. Therefore, the capacitor C2 is charged through the resistor R4 to which the DC voltage Vcc is applied, and the voltage signal at the connection point between the resistor R4 and the capacitor C2 becomes H. This voltage signal is sequentially inverted by the two inverters I 1 and I 2 and output as a pulse signal having a predetermined time width as shown in FIG. 6C, and is input to the CPU 33. On the other hand, when the input signal (B) is at a low level (L≈0), the transistor Q1 is turned on, so the voltage of the resistor R2 is high (≈Vcc), and this is applied to the base of the transistor Q2 via the resistor R3. Therefore, the transistor Q2 is also turned on. Therefore, the capacitor C2 is discharged, and the voltage signal at the connection point between the resistor R4 and the capacitor C2 is L.

  The CPU 33 counts the number of pulses output from the one-shot timer 32 as described above, and determines that the discharge is slight when the number exceeds a preset number (for example, the number per second) N. As a result, the CPU 33 sends a signal for cutting off the power supply to the power supply circuit 3 to the control circuit 4 in FIG. Send an alarm signal to light or flash. These measures, that is, the interruption of the power supply prevents accidents such as ignition and burnout of the power supply circuit 3 and the ion generating device main body, and notifies the deterioration of the insulating property of the discharge electrode by an alarm display and adheres to the periphery of the electrode. It can promote removal of wrinkles and dirt.

  In the above-described embodiment, the current flowing through the resistor 16 connected to the ground side of the secondary winding 5b of the winding transformer 5 is shown as "PD detection (1)" in FIG. Although the slight discharge is detected by (return current of the ground side output), it is detected from the discharge needle side output of the winding transformer 5 as shown as “PD detection (2)” in FIG. Also good.

  Further, although the current generated by the fine discharge is generated on the secondary side of the transformer, the same current waveform is also generated on the primary side due to the mutual induction action of the transformer, so it may be detected from the primary side of the winding transformer 5. .

  FIG. 7 shows an embodiment in the case where a slight discharge is detected from the DC power supply side or the ground side of the pulse train output circuit 6 connected to the primary side of the winding transformer 5. As shown in FIG. 7, when detecting from the ground side of the pulse train output circuit 6, a resistor 35 is connected between the connection point of the two switch elements 8 and 10 on the ground side and the ground. Then, as shown as “PD detection (3)”, a PD detection signal is taken out from the connection point b. On the other hand, when detecting from the DC power supply (constant voltage source Vcc) side of the pulse train output circuit 6, as shown as “PD detection (4)”, the connection point a between the two switch elements 7 and 9 on the DC power supply side is shown. The PD detection signal is taken out from.

  In the above embodiment, the high-voltage power supply circuit is configured to include an H-bridge circuit. However, the configuration is not limited to the H-bridge circuit, and any configuration that can output a high voltage necessary for the discharge electrode may be used. The voltage applied to the primary side of the winding transformer may be direct current or alternating current, and the high voltage output from the secondary side may be either direct current or alternating current.

  For example, as shown in FIG. 8A, a power supply circuit configured to connect an AC power supply (for example, commercial frequency power supply) 36 to the primary winding 5a of the winding transformer 5 and apply an AC voltage to the primary side may be used. . In this case, the resistor 37 is connected to the ground side of the primary winding 5a, and the PD detection signal is taken out from the connection point c. Alternatively, the PD detection signal may be extracted from a point d on the non-ground side of the primary winding 5a. Further, when detecting a slight discharge from the secondary side of the winding transformer 5, a resistor 38 is connected to the ground side of the secondary winding 5b of the winding transformer 5, and a PD detection signal is taken out from the connection point e. . Or you may make it detect from the point f by the side of the non-grounding of the secondary winding 5b.

  Further, as shown in FIG. 8B, a DC constant voltage Vcc is applied to one end of the primary winding 5a of the winding transformer 5 and an oscillation circuit 39 is connected to the other end so that a clock signal such as a clock signal is connected to the primary side. Apply AC high frequency voltage. The secondary winding 5b may be connected to a DC high voltage output circuit 40 such as a cockcroft circuit, for example, and may be a power supply circuit configured to output a DC high voltage from the secondary side. In this case, the PD detection signal may be extracted from either the constant voltage side or the oscillation circuit side of the primary winding 5a. Alternatively, the resistor 38 is connected to the ground side of the secondary winding 5b, and the PD detection signal is taken out from the connection point, or from the non-ground side of the secondary winding 5b or the output terminal of the DC high voltage output circuit 40, You may make it take out PD detection signal.

  In the conventional example shown in FIG. 9, the power supply circuit 41 includes an oscillation circuit 51 that generates an AC high-frequency voltage by applying a DC voltage, and a winding transformer 52 that boosts the generated AC high-frequency voltage. The oscillation circuit 51 is connected to the commercial power supply 54 via the DC power supply circuit 53, and the winding transformer 52 receives the output of the oscillation circuit 51 by the primary winding and outputs it as a high voltage by the secondary winding by electromagnetic induction. Output from the terminal to the high voltage cable 42. Alternatively, the high frequency voltage may be boosted using a piezoelectric transformer made of piezoelectric ceramics instead of the winding transformer 52. In any case, the PD detection signal can be extracted from either the primary side or the secondary side of the winding transformer 52 as in FIG. 8A or 8B.

  The detection of the fine discharge according to the present invention can also be applied to a configuration in which a high voltage is applied to the discharge electrode by the known high voltage power supply circuit as described above.

The figure which shows the outline of the circuit structure of the ion generator in one Embodiment of this invention. The graph which shows the relationship between the on-off control of each switch element in the high voltage power supply circuit of FIG. The graph which shows the example of the waveform of the alternating current high voltage which generate | occur | produces in the secondary winding of the winding transformer of FIG. The block diagram which shows the structure of the fine electric discharge detection apparatus used for the ion generator of embodiment. FIG. 5 is a circuit diagram showing an example of a circuit configuration of the slight discharge detection device of FIG. 4. FIG. 6 is an enlarged waveform diagram showing a slight discharge detection signal and a part thereof in each part (A), (B), and (C) of the circuit of FIG. 5. The figure which shows the circuit structure in the case of detecting fine discharge from the primary side of the coil | winding transformer of FIG. The figure which shows the example in the case of detecting a slight discharge in the power supply circuit which applies an alternating current or a DC voltage to the primary side of a winding transformer. The figure which shows the structural example of the conventional ion production | generation apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ion generator, 2 ... Discharge needle, 3 ... High voltage power supply circuit, 4 ... Control circuit, 5 ... Winding transformer, 6 ... Pulse train output circuit, 7-10 ... Switch element, 11 ... 1st series circuit, 12 2nd series circuit, 13 ... Parallel circuit, 14 ... DC power supply, 15 ... Counter electrode, 16 ... Resistor, 30 ... PD detector, 31 ... High-pass filter, 32 ... One-shot timer, 33 ... Microcomputer, 34 ... Alarm indicator, 35 ... resistor.

Claims (6)

In an ion generator that generates a corona discharge from the discharge electrode by applying a high voltage to the discharge electrode and generates air ions by the corona discharge,
A high-voltage power supply circuit that outputs a high voltage applied to the discharge electrode;
A fine discharge detection means for generating a detection signal corresponding to the fine discharge generated separately from the corona discharge when a high voltage is applied to the discharge electrode from the high-voltage power supply circuit;
An ion generation apparatus comprising: a fine discharge determination means for outputting an alarm signal when it is determined that the discharge is a slight discharge based on a detection signal from the fine discharge detection means.   2. The ion generating apparatus according to claim 1, wherein the fine discharge determining means outputs a signal for cutting off power supply to the high-voltage power supply circuit together with the alarm signal when it is determined that the discharge is fine.   The fine discharge detection means inputs a voltage generated by a current flowing through a resistor connected to the ground electrode side of the discharge electrode from the output portion of the high-voltage power supply circuit as the detection signal to the fine discharge determination means. The ion generating apparatus according to claim 1, wherein the ion generating apparatus is configured.   The fine discharge detection means is configured to input, to the fine discharge determination means, a voltage generated by a current flowing through an output portion connected to the acicular electrode of the discharge electrode from the high-voltage power supply circuit as the detection signal. The ion generating apparatus according to claim 1, wherein: The high-voltage power supply circuit includes a winding transformer having a primary winding and a secondary winding, and a pulse train output circuit that outputs a plurality of pulse train voltages applied to the primary winding,
The fine discharge detection means uses, as the detection signal, a voltage generated by a current flowing through a resistor connected to a ground terminal of the pulse train output circuit, or a voltage generated by a current flowing through a constant voltage source side of the pulse train output circuit. The ion generating apparatus according to claim 1, wherein the ion generating apparatus is configured to input to the fine discharge determination unit.   The high-voltage power circuit includes a winding transformer that boosts a voltage applied to the primary side to generate a high voltage on the secondary side, an AC power source that applies an AC voltage to the primary side of the winding transformer, or a DC voltage The ion generator according to claim 1, further comprising: an oscillation circuit that generates an alternating-current high-frequency voltage on the primary side of the winding transformer by applying a voltage.

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