Voltage generation circuit and discharge device

Abstract

To provide a voltage generation circuit and a discharge device capable of easily suppressing reduction in an amount of generation of ions from a discharge electrode.SOLUTION: A voltage generation circuit 1 includes a transformer 6 and a pulse generation unit 2. The transformer 6 has a primary winding 61 and a secondary winding 62. The pulse generation unit 2 supplies a pulsed primary current I1 to the primary winding 61. The pulse generation unit 2 has a control unit 22. The control unit 22 controls at least one of a pulse width and a period of the primary current I1 as a control value.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a voltage generating circuit and a discharge device that include a transformer. [Background technology]

[0002] As a related technique, a voltage generation circuit (high voltage output device) that includes a transformer (winding transformer) and generates a high voltage on the secondary side of the transformer is known (see, for example, Patent Document 1). This voltage generation circuit is used, for example, in a discharge device (ion generator) and applies a high voltage generated on the secondary side of the transformer to an ion generation element having two electrodes, causing the ion generation element to generate ions.

[0003] This voltage generation circuit connects a first terminal connected to the output of the secondary side of the transformer to one electrode of the ion generation element, and a second terminal connected to a ground line (reference potential line) to the other electrode of the ion generation element. The space between the two electrodes of the ion generation element is open, allowing air to freely flow in and out. This generates a high voltage between the electrodes, creating a discharge state, making it possible to generate ions or ozone from the air. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-34174 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the configuration of the above-mentioned related art, especially after a long period of time has passed since the start of use, the amount of ions generated from the discharge electrode may decrease even if the same high voltage is applied, for example, due to deterioration (including adhesion of foreign matter) of the discharge electrode (the electrode of the ion generating element).

[0006] An object of the present invention is to provide a voltage generating circuit and a discharge device that can easily suppress a decrease in the amount of ions generated from a discharge electrode. [Means for solving the problem]

[0007] A voltage generating circuit according to one aspect of the present invention includes a transformer and a pulse generating unit. The transformer has a primary winding and a secondary winding. The pulse generating unit supplies a pulsed primary current to the primary winding. The pulse generating unit has a control unit. The control unit controls at least one of a pulse width and a period of the primary current as a control value.

[0008] A discharge device according to one aspect of the present invention includes the voltage generating circuit and the discharge electrode. Effect of the Invention

[0009] According to the present invention, it is possible to provide a voltage generating circuit and a discharge device that can easily suppress a decrease in the amount of ions generated from a discharge electrode. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic perspective view showing the appearance of the discharge device according to the first embodiment. [Diagram 2] FIG. 2 is a schematic block diagram showing the configuration of the discharge device according to the first embodiment. [Diagram 3] FIG. 3 is a schematic circuit diagram showing a specific example of the voltage generating circuit according to the first embodiment. [Figure 4] FIG. 4 is a schematic explanatory diagram showing an example of the operation of the voltage generating circuit according to the first embodiment. [Diagram 5] FIG. 5 is a schematic explanatory diagram showing the amount of ions generated by the discharge device according to the first embodiment. [Figure 6] FIG. 6 is a flowchart illustrating an example of the operation of the control unit of the voltage generating circuit according to the first embodiment. [Figure 7] FIG. 7 is a schematic explanatory diagram showing an example of the operation of the voltage generating circuit according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

[0012] (Embodiment 1) [1] Overall structure First, the overall configuration of a discharge device 10 according to this embodiment will be described with reference to FIGS.

[0013] The discharge device 10 includes a voltage generating circuit 1 (see FIG. 2) and a discharge electrode 5. In this embodiment, the discharge electrode 5 includes a first discharge electrode 51 and a second discharge electrode 52. The discharge device 10 according to this embodiment includes an induction electrode in addition to the first discharge electrode 51 and the second discharge electrode 52.

[0014] The voltage generating circuit 1 is configured to be able to apply a voltage (high voltage) between the discharge electrode 5 (first discharge electrode 51 and second discharge electrode 52) and the induction electrode. The discharge device 10 generates positive ions and negative ions as discharge products by applying a voltage to the discharge electrode 5 (first discharge electrode 51 and second discharge electrode 52) and generating a discharge between the discharge electrode 5 and the induction electrode.

[0015] In this embodiment, as an example, the discharge device 10 is installed at a position facing an air passage through which an air current (wind) generated by an air current generating device such as a fan passes, and is disposed so as to expose at least the first discharge electrode 51 and the second discharge electrode 52 to the air passage. As a result, the discharge products (positive ions and negative ions) generated by the discharge device 10 are released into a desired space (such as a room) from the air outlet on the air current passing through the air passage.

[0016] As shown in FIG. 1, the discharge device 10 according to this embodiment includes, in addition to a first discharge electrode 51 and a second discharge electrode 52, an electrode substrate 54, a case 55, an electrode protection section 56, a partition wall 57, and the like.

[0017] The case 55 is made of an electrically insulating resin and has, for example, a rectangular parallelepiped (box-like) shape having a length in one direction (the vertical direction in FIG. 1). The case 55 accommodates the electrode board 54, the circuit board, etc. One surface of the case 55 is formed with holes for exposing at least the first discharge electrode 51 and the second discharge electrode 52.

[0018] The electrode substrate 54 is provided with a first discharge electrode 51 and a second discharge electrode 52 protruding in a normal direction from one surface of the electrode substrate 54. In the present embodiment, as an example, the first discharge electrode 51 and the second discharge electrode 52 are electrodes having brush-shaped tips. The first discharge electrode 51 and the second discharge electrode 52 protrude from one surface of the electrode substrate 54 at the same height position and are arranged side by side in one direction (the longitudinal direction of the case 55) with a gap therebetween.

[0019] Moreover, an induction electrode separate from the first discharge electrode 51 and the second discharge electrode 52 is provided around the first discharge electrode 51 and the second discharge electrode 52 on one surface of the electrode substrate 54.

[0020] The circuit board housed in the case 55 has a voltage generation circuit 1. The circuit board on which the voltage generation circuit 1 is formed is electrically connected to an electrode board 54. As a result, the voltage generation circuit 1 is electrically connected to the first discharge electrode 51 and the second discharge electrode 52 mounted on the electrode board 54. Thus, the voltage generated by the voltage generation circuit 1 is supplied to the first discharge electrode 51 and the second discharge electrode 52 of the electrode board 54 and the induction electrode.

[0021] In this embodiment, the voltage generation circuit 1 generates positive and negative high voltages (high pressure) and applies them to the discharge electrodes 5 (first discharge electrode 51 and second discharge electrode 52), thereby generating a discharge at the discharge electrodes 5. The "high voltage (high pressure)" in this disclosure is a voltage that can generate a discharge at the discharge electrode 5 when applied to the discharge electrode 5, and is, for example, a peak-to-peak voltage of about several kV (8 kV as an example).

[0022] Specifically, the voltage generating circuit 1 applies a positive high voltage pulse (for example, a voltage of +several kV) to the first discharge electrode 51, and applies a negative high voltage pulse (for example, a voltage of -several kV) to the second discharge electrode 52. In other words, the first discharge electrode 51 is an example of a positive side discharge electrode, and the second discharge electrode 52 is an example of a negative side discharge electrode.

[0023] In this way, the voltage generating circuit 1 applies to the discharge electrode 5 a voltage large enough to generate a discharge between the induction electrode and the first discharge electrode 51 and the second discharge electrode 52. Here, positive ions are generated as a discharge product from the first discharge electrode 51, which is the positive discharge electrode, and negative ions are generated as a discharge product from the second discharge electrode 52, which is the negative discharge electrode.

[0024] Particularly in this embodiment, as shown in FIG. 2, the voltage generating circuit 1 includes a pulse generating section 2 and a boosting circuit 3.

[0025] The pulse generating unit 2 is electrically connected to the input connector 4. The pulse generating unit 2 receives a DC voltage (from the input connector 4) and applies (outputs) a pulse (impulse) voltage to the boost circuit 3.

[0026] The boost circuit 3 is electrically connected to the pulse generating unit 2. The boost circuit 3 boosts the pulse voltage applied from the pulse generating unit 2, and applies (outputs) the boosted high-voltage pulse to the discharge electrode 5. In other words, the boost circuit 3 is also electrically connected to the discharge electrodes 5 (first discharge electrode 51 and second discharge electrode 52), and applies a positive voltage V1 to the first discharge electrode 51, and applies a negative voltage V2 to the second discharge electrode 52.

[0027] The electrode protection part 56 is disposed around the first discharge electrode 51 and the second discharge electrode 52. In this embodiment, the electrode protection part 56 is formed integrally with the case 55, and protrudes from the electrode holding surface 53 in the same direction as the first discharge electrode 51 and the second discharge electrode 52. The height of the electrode protection part 56 is greater than the height of the tips of the first discharge electrode 51 and the second discharge electrode 52.

[0028] The electrode protection part 56 is made of a pair of frame-shaped members located on both sides in the width direction of the case 55 for each of the first discharge electrode 51 and the second discharge electrode 52. Specifically, the electrode protection part 56 is made of a hollow frame inside which the first discharge electrode 51 and the second discharge electrode 52 are located. However, the shape of the electrode protection part 56 is not limited to the shape shown in FIG.

[0029] The partition wall 57 is made of an electrically insulating resin. The partition wall 57 is provided between the first discharge electrode 51 and the second discharge electrode 52 in the direction in which the first discharge electrode 51 and the second discharge electrode 52 are arranged (the longitudinal direction of the case 55 in this embodiment) so as to separate the space between the first discharge electrode 51 and the second discharge electrode 52. In this embodiment, the partition wall 57 is formed integrally with the case 55 and protrudes from the electrode holding surface 53 in the same direction as the first discharge electrode 51 and the second discharge electrode 52. The height of the partition wall 57 is higher than the height of the tips of the first discharge electrode 51 and the second discharge electrode 52.

[0030] The discharge device 10 is removably attached to the main body of an electrical device, such as an air purifier, a heating device, or a cooling device. In other words, the discharge device 10 and the main body of the electrical device are separate entities, and the main body of the electrical device holds the discharge device 10 in a removably state. Therefore, for example, by removing the discharge device 10 from the main body of the electrical device, maintenance of the discharge device 10 (including inspection, replacement, repair, etc.) can be easily performed.

[0031] In this embodiment, the discharge device 10 has an input connector 4 electrically connected to the voltage generating circuit 1 on the circuit board, etc. The input connector 4 is disposed at one end in the longitudinal direction of the case 55 (the lower end in the example of FIG. 1). The input connector 4 is detachably coupled to a mating connector held in the main body of the electrical device.

[0032] When the input connector 4 and the mating connector are coupled, the input connector 4 and the mating connector are electrically connected, and the discharge device 10 is electrically connected to the main body of the electrical device. In this embodiment, as an example, the input connector 4 and the mating connector are plug-in connectors that are detachable along the longitudinal direction of the case 55. Therefore, it is possible to couple (electrically connect) the input connector 4 and the mating connector by sliding the case 55 along the longitudinal direction of the case 55 from a position where the input connector 4 faces the mating connector.

[0033] [2] Specific configuration of the voltage generation circuit Next, a specific configuration of the voltage generating circuit 1 according to this embodiment will be described with reference to FIG.

[0034] In this embodiment, the boost circuit 3 of the voltage generating circuit 1 includes a transformer 6, as shown in Fig. 3. Also, the pulse generating section 2 of the voltage generating circuit 1 includes a primary voltage generating section 21, a control section 22, and a switching element Q1, as shown in Fig. 3. In short, the voltage generating circuit 1 according to this embodiment includes the transformer 6 and the pulse generating section 2, and the pulse generating section 2 has the control section 22.

[0035] The transformer 6 has a primary winding 61 and a secondary winding 62. The primary winding 61 and secondary winding 62 of the transformer 6 are magnetically coupled, and when a current (primary current I1) flows through the primary winding 61 and a magnetic flux is generated, an induced electromotive force is generated in the secondary winding 62. In this embodiment, the transformer 6 boosts the voltage applied to the primary winding 61, and generates a boosted voltage V0 between both ends (a first end 621 and a second end 622) of the secondary winding 62.

[0036] The secondary winding 62 has a first end 621 and a second end 622. The first end 621, which is one end of the secondary winding 62, is electrically connected to the first discharge electrode 51, which is a positive discharge electrode, and the second discharge electrode 52, which is a negative discharge electrode, via rectifying elements (diodes, etc.) that are oriented in the opposite directions to each other. On the other hand, the second end 622, which is the other end of the secondary winding 62, is electrically connected to an induction electrode.

[0037] As a result, the voltage generating circuit 1 applies the voltage V0, which is boosted by the boost circuit 3 and generated between both ends (first end 621 and second end 622) of the secondary winding 62 of the transformer 6, to the discharge electrode 5. Specifically, the voltage generating circuit 1 applies a positive voltage V1 (see FIG. 2) between the first discharge electrode 51 and the induction electrode, and applies a negative voltage V2 (see FIG. 2) between the second discharge electrode 52 and the induction electrode.

[0038] The voltage generating circuit 1 has an output terminal for electrically connecting the discharge electrodes 5 (the first discharge electrode 51 and the second discharge electrode 52), and generates a boosted voltage V0 at the output terminal. In the present disclosure, a "terminal" such as an output terminal does not have to be a terminal component for connecting an electric wire or the like, and may be, for example, a lead of an electronic component, or a part of a conductor included in a circuit board.

[0039] The primary winding 61 of the transformer 6 is electrically connected to the output of the pulse generating unit 2. The pulse generating unit 2 supplies a pulsed primary current I1 to the primary winding 61. In other words, the pulse generating unit 2 does not continuously pass a current through the primary winding 61, but intermittently supplies a pulsed primary current I1 having a certain pulse width W1 (see FIG. 4) to the primary winding 61. This makes it possible to input a relatively small amount of electrical energy to the primary winding 61, while generating a relatively large (high voltage) voltage V0 in the secondary winding 62 by an induced electromotive force.

[0040] The pulse generating unit 2 receives a DC voltage from the main body of the electric device via the input connector 4, and supplies a pulsed primary current I1 to the primary winding 61. In this embodiment, the pulse generating unit 2 supplies the pulsed primary current I1 to the primary winding 61 periodically with a certain period T1 (see FIG. 4).

[0041] Specifically, a primary winding 61 and a switching element Q1 are electrically connected in series between output terminals of a primary voltage generating section 21 of a pulse generating section 2. The primary voltage generating section 21 is a circuit that generates a primary voltage to be applied to the primary winding 61, and receives a DC voltage from the main body of an electric device via an input connector 4, and outputs a DC voltage of a predetermined magnitude (voltage value).

[0042] The switching element Q1 is a semiconductor element, more specifically, an active element such as a transistor, etc. In this embodiment, as an example, the switching element Q1 is an enhancement type n-channel Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET).

[0043] This switching element Q1 changes the drain-source conduction state according to a gate voltage (gate-source voltage) applied to a control terminal (gate terminal). The switching element Q1 has a drain connected to the transformer 6 (primary winding 61) and a source connected to the circuit ground. In other words, the drain-source of the switching element Q1 is electrically connected in series with the primary winding 61 of the transformer 6 to form a current path. Therefore, the primary current I1 flowing through the primary winding 61 of the transformer 6 is controlled by changing the drain-source conduction state of the switching element Q1.

[0044] The switching element Q1 can basically be switched between two states, an on state and an off state. The on state of the switching element Q1 is a state in which the drain-source of the switching element Q1 is conductive, and the off state of the switching element Q1 is a state in which the drain-source of the switching element Q1 is cut off. In other words, the primary current I1 flows through the primary winding 61 only while the switching element Q1 is in the on state, and the primary current I1 does not flow through the primary winding 61 when the switching element Q1 is in the off state.

[0045] The control unit 22 of the pulse generating unit 2 controls the switching element Q1. That is, the control unit 22 is electrically connected to the gate of the switching element Q1 and changes the drain-source conduction state of the switching element Q1. Specifically, the control unit 22 outputs a control signal Si1 to the gate (control terminal) of the switching element Q1, and turns the switching element Q1 on when the control signal Si1 is at H (High) level, and turns the switching element Q1 off when the control signal Si1 is at L (Low) level.

[0046] In this embodiment, the control unit 22 is mainly configured as a computer having one or more processors and one or more memories as hardware, and capable of implementing various functions by the one or more processors executing programs recorded in the one or more memories. The computer referred to in this disclosure includes a microcontroller having one or more processors and one or more memories.

[0047] In the present embodiment, as an example, the control unit 22 is mainly configured as a microcontroller, and one or more processors execute programs to realize the functions of the control unit 22. The one or more processors in the microcontroller are configured as one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

[0048] According to the above configuration, the control unit 22 can control (adjust) the pulse width W1 and period T1 of the primary current I1 by the control signal Si1 output to the gate (control terminal) of the switching element Q1. That is, the width (time width) from the rising edge (point of change from L level to H level) to the falling edge (point of change from H level to L level) in the control signal Si1 defines the pulse width W1 of the primary current I1. Also, the time interval (period) from the rising edge (point of change from L level to H level) to the next rising edge in the period of the control signal Si1 defines the period T1 of the primary current I1.

[0049] In particular, the control unit 22, which is mainly composed of a computer such as a microcontroller, can output an arbitrary control signal Si1 depending on the program, and therefore can control the pulse width W1 and period T1 of the primary current I1 by software. As a result, the control unit 22 of the pulse generating unit 2 can control each of the pulse width W1 and period T1 of the primary current I1 flowing through the primary winding 61 by controlling the switching element Q1.

[0050] As described above, the voltage generating circuit 1 according to this embodiment includes the transformer 6 and the pulse generating unit 2. The transformer 6 has a primary winding 61 and a secondary winding 62. The pulse generating unit 2 supplies a pulsed primary current I1 to the primary winding 61. The pulse generating unit 2 includes a control unit 22. The control unit 22 controls at least one of the pulse width W1 and the period T1 of the primary current I1 as a control value.

[0051] The "control value" in this disclosure is a value that can be controlled (i.e., set / changed) by the control unit 22, and is controlled (set / changed) within a preset variable range, for example. The control unit 22 may set any value within the variable range as the "control value", or may set as the "control value" any value selected from a plurality of values ​​set in multiple stages within the variable range. Here, the control value is at least one of the pulse width W1 and the period T1 of the primary current I1.

[0052] According to this embodiment, the voltage generating circuit 1 is capable of controlling at least one (control value) of the pulse width W1 and the period T1 of the primary current I1 supplied to the primary winding 61 of the transformer 6 by the control unit 22, rather than setting them to fixed values. As will be described in detail later, when at least one of the pulse width W1 and the period T1 of the primary current I1 changes, the electrical energy output from the secondary winding 62 of the transformer 6 per unit time also changes.

[0053] As an example, the voltage generation circuit 1 can increase the electrical energy output from the secondary winding 62 of the transformer 6 by controlling the control value, and can increase the voltage V0 applied to the discharge electrode 5. After a long time has passed since the start of use of the discharge device 10, the amount of ions generated from the discharge electrode 5 may decrease due to deterioration of the discharge electrode 5 (including adhesion of foreign matter, etc.). For example, in such a case, the voltage generation circuit 1 can control the control value to increase the voltage V0 applied to the discharge electrode 5 and increase the amount of ions generated from the discharge electrode 5, thereby suppressing the decrease in the amount of ions generated from the discharge electrode 5. Therefore, the voltage generation circuit 1 according to this embodiment has the advantage of easily suppressing the decrease in the amount of ions generated from the discharge electrode 5.

[0054] Furthermore, the voltage generating circuit 1 according to this embodiment controls the control value on the primary side, not the secondary side, of the transformer 6 that generates the high voltage. Therefore, for example, there is no need to switch the high voltage, and the control value can be controlled even with components that have a relatively low withstand voltage.

[0055] In addition, in the voltage generating circuit 1, it is also possible to change the voltage V0 output from the secondary winding 62 by controlling the voltage applied to the primary winding 61, but in that case, a pulse generating unit 2 capable of switching the output voltage is required on the primary side of the transformer 6. In contrast, in this embodiment, the control unit 22 controls at least one of the pulse width W1 and the period T1 of the pulsed primary current I1 as a control value, so there is no need to switch the output voltage of the pulse generating unit 2, and the circuit configuration can be simplified.

[0056] [3] Example of voltage generation circuit operation Next, an example of the operation of the voltage generating circuit 1 according to this embodiment will be described with reference to FIGS.

[0057] 4 is an explanatory diagram showing an example of the relationship between the primary current I1 flowing through the primary winding 61 of the transformer 6 and the voltage V0 output from the secondary winding 62 of the transformer 6, with the horizontal axis representing time. Fig. 4 shows a schematic diagram of the change in voltage V0 when the pulse width W1 of the primary current I1 is changed from "small" to "large."

[0058] The control unit 22 controls at least one of the pulse width W1 and the period T1 of the primary current I1 as a control value, but in this embodiment, the control unit 22 controls the pulse width W1 of the primary current I1 as a control value. That is, in this embodiment, the control unit 22 controls only the pulse width W1 of the pulse width W1 and the period T1 of the primary current I1 as a control value, and the period T1 of the primary current I1 is fixed (unchanged).

[0059] The "pulse width W1" of the primary current I1 in the present disclosure means the width (time width) from the timing when the switching element Q1 is turned on and the supply of the primary current I1 to the primary winding 61 starts to the timing when the switching element Q1 is turned off and the supply of the primary current I1 to the primary winding 61 stops. In other words, the pulse width W1 is represented by the time from the rise to the fall of the primary current I1 as shown in Fig. 4, and is expressed in units of, for example, seconds (including microseconds, etc.).

[0060] On the other hand, the "period T1" of the primary current I1 in the present disclosure means the interval (time interval) from the timing when the switching element Q1 is turned on and the supply of the primary current I1 to the primary winding 61 is started to the timing when the switching element Q1 is turned on the next time and the supply of the primary current I1 to the primary winding 61 is started. In other words, as shown in Fig. 4, the period T1 is represented by the time from the rising edge of the primary current I1 to the next rising edge, and is expressed in units of, for example, seconds (including milliseconds, etc.).

[0061] Here, in the discharge device 10, when a primary current I1 flows through the primary winding 61 of the transformer 6 and a voltage V0 is output from the secondary winding 62, a discharge occurs at the discharge electrode 5. Therefore, the period T1 of the primary current I1 determines the number of times the primary current I1 flows per unit time, and thus determines the number of times discharge occurs at the discharge electrode 5 per unit time, that is, the frequency of discharge. The smaller (shorter) the period T1 of the primary current I1, the higher the frequency of discharge, and the larger (longer) the period T1 of the primary current I1, the lower the frequency of discharge.

[0062] In this embodiment, as described above, the control unit 22 of the pulse generating unit 2 controls the pulse width W1 of the primary current I1 as a control value while keeping the period T1 of the primary current I1 fixed (constant). As an example, the period T1 of the primary current I1 is set to any value between 1 / 300 sec and 1 / 100 sec so that the frequency of the primary current I1 is any value between 100 Hz and 300 Hz.

[0063] 4, basically, as the pulse width W1 of the primary current I1 becomes larger (longer), the magnitude (amplitude) A1 of the voltage V0 output from the secondary winding 62 of the transformer 6 becomes larger. In other words, as the pulse width W1 of the primary current I1 becomes smaller (shorter), the magnitude (amplitude) A1 of the voltage V0 output from the secondary winding 62 of the transformer 6 becomes smaller.

[0064] 4, the magnitude A1 of the voltage V0 is shown as peak-to-peak. However, similarly, the magnitude of the voltage changes according to the pulse width W1 of the primary current I1 for the positive voltage output to the first discharge electrode 51, which is the positive discharge electrode, and the negative voltage output to the second discharge electrode 52, which is the negative discharge electrode.

[0065] That is, when the pulse width W1 becomes larger, the electrical energy (amount of power) supplied to the primary winding 61 of the transformer 6 increases, and therefore the voltage V0 output from the secondary winding 62 of the transformer 6 also increases. Conversely, when the pulse width W1 becomes smaller, the electrical energy (amount of power) supplied to the primary winding 61 of the transformer 6 decreases, and therefore the voltage V0 output from the secondary winding 62 of the transformer 6 also decreases.

[0066] However, the voltage V0 output from the secondary winding 62 does not increase infinitely, but reaches a maximum (peak) at a certain pulse width W1. In this disclosure, the control value (pulse width W1) at which the voltage V0 is maximum within the adjustable variable range of the control value (pulse width W1 in this embodiment) is defined as the "optimum value." In other words, the voltage V0 output from the secondary winding 62 reaches a maximum when the control value, that is, the pulse width W1, is at an optimal value, and when the control value, that is, the pulse width W1, changes to a value smaller or larger than the optimal value, the voltage V0 output from the secondary winding 62 drops (becomes smaller).

[0067] Therefore, in this embodiment, the adjustment range of the pulse width W1, which is a control value, is limited so that the optimum value is set as the upper limit, and the control value (pulse width W1) at which the voltage V0 output from the secondary winding 62 drops (becomes smaller) appropriately is set as the lower limit. In this way, the control unit 22 can gradually increase (increase) the voltage V0 output from the secondary winding 62, for example, by gradually increasing the pulse width W1 toward the upper limit within the adjustment range. Moreover, the control unit 22 does not use a range exceeding the optimum value as the pulse width W1, which is a control value, and therefore it is possible to avoid a decrease in power transmission efficiency caused by making the pulse width W1 of the primary current I1 larger (longer) than necessary.

[0068] In this embodiment, when the control value at which the electrical energy output from the secondary winding 62 per unit time is maximized is set to the optimal value, the control unit 22 sets the initial value of the control value to a value different from the optimal value. Specifically, in this embodiment, for the pulse width W1 which is the control value, a value smaller (shorter) than the optimal value is set as the initial value of the control value (pulse width W1) within the adjustment range with the optimal value as the upper limit as described above.

[0069] The "electrical energy" here includes the amount of power, and is defined by, for example, the voltage V0, the current, and the time. In this embodiment, the voltage V0 output from the secondary winding 62 changes by controlling the control value (pulse width W1), so the control value when the electrical energy is at its maximum is synonymous with the control value when the voltage V0 is at its maximum. Also, the "initial value" here is, for example, the value of the control value (pulse width W1 in this embodiment) that is set when the discharge device 10 starts to be used, that is, when the voltage generating circuit 1 starts to be used.

[0070] In short, in this embodiment, when starting to use the discharge device 10, the control unit 22 controls the control value (pulse width W1) to an initial value that is different from the optimal value at which the voltage V0 output from the secondary winding 62 is at its maximum. In this embodiment, as an example, the control value (pulse width W1) at which the voltage V0 is 60% of its maximum value is set as the initial value. As a result, when starting to use the discharge device 10, the voltage generating circuit 1 operates in a state in which the voltage V0 output from the secondary winding 62 is suppressed to about 60% of the maximum, rather than at its maximum.

[0071] Therefore, the control unit 22 can increase the voltage V0 output from the secondary winding 62 (from 60%) by, for example, changing the control value (pulse width W1) from an initial value to approach an optimal value as time passes from when the discharge device 10 was first used. As a result, even if a long time has passed since the discharge device 10 was first used and the discharge electrode 5 has deteriorated (including adhesion of foreign matter, etc.), for example, the voltage generation circuit 1 can increase the voltage V0 applied to the discharge electrode 5 and increase the amount of ions generated from the discharge electrode 5, thereby suppressing a decrease in the amount of ions generated from the discharge electrode 5.

[0072] As an example, when deterioration of the discharge electrode 5 occurs, the amount of ions generated (ion concentration) may decrease over time from the start of use of the discharge device 10, as shown by the imaginary line (double-dashed line) in Fig. 5. In response to this, in the voltage generation circuit 1 according to this embodiment, the control unit 22 gradually increases the control value (pulse width W1) to increase the voltage V0 applied to the discharge electrode 5, and as shown in Fig. 5, it is possible to suppress the decrease in the amount of ions generated (ion concentration) from the discharge electrode 5.

[0073] Furthermore, when a specific condition is satisfied, the control unit 22 changes the control value to the side where the electric energy is increased. In this embodiment, as described above, within the adjustment range with the optimal value as the upper limit, a value smaller (shorter) than the optimal value is set as the initial value of the control value (pulse width W1), so that when a specific condition is satisfied, the control unit 22 changes the control value (pulse width W1) to be larger (longer).

[0074] The "specific condition" in the present disclosure is a pre-specified event that triggers the control unit 22 to change the control value (pulse width W1) to increase the electric energy. According to this configuration, the control unit 22 can automatically change the control value when the specific condition is satisfied by determining whether the specific condition is satisfied, without relying on a human operation.

[0075] Specifically, in this embodiment, the specific condition includes a time condition related to an elapsed time. The "elapsed time" here is, for example, the time that has elapsed since the start of use of the discharge device 10, that is, the start of use of the voltage generating circuit 1. The elapsed time may be the accumulated usage time that is accumulated only during the period when the power supply of the discharge device 10 is on (the period during operation), or may be the time that is counted regardless of whether the power supply of the discharge device 10 is on or off.

[0076] In this embodiment, as an example, the time condition includes that the elapsed time (assumed to be the cumulative usage time) reaches a predetermined threshold time. In other words, when the elapsed time reaches the threshold time, the control unit 22 determines that the specific condition is satisfied, and changes the control value (pulse width W1) to be larger (longer). Here, the elapsed time can be measured, for example, by a timer or the like. The elapsed time is recorded in a non-volatile memory or the like so that it is not reset even if the power of the discharge device 10 is turned off.

[0077] According to this configuration, even if a long time has passed since the start of use of the discharge device 10 and deterioration of the discharge electrode 5 occurs, the voltage generating circuit 1 can suppress a decrease in the amount of ions generated from the discharge electrode 5 by increasing the voltage V0 applied to the discharge electrode 5 and increasing the amount of ions generated from the discharge electrode 5.

[0078] In this embodiment, the specific conditions include product conditions related to products obtained by the electric energy. The "products" referred to here are objects generated by the electric energy (voltage V0) output from the secondary winding 62, and ions (positive ions and negative ions) generated at the discharge electrode are an example of the products.

[0079] In the present embodiment, as an example, the product condition includes that the amount of ions generated (ion concentration) falls below a predetermined threshold. In other words, when the amount of ions generated falls below the threshold, the control unit 22 determines that the specific condition is satisfied, and changes the control value (pulse width W1) to be larger (longer). Here, the amount of ions generated (ion concentration) can be measured, for example, by an ion concentration meter (sensor) or the like. The amount of ions generated does not need to be measured constantly, but is measured intermittently.

[0080] According to this configuration, even if a long time has passed since the start of use of the discharge device 10 and deterioration of the discharge electrode 5 occurs, the voltage generating circuit 1 can suppress a decrease in the amount of ions generated from the discharge electrode 5 by increasing the voltage V0 applied to the discharge electrode 5 and increasing the amount of ions generated from the discharge electrode 5.

[0081] In this embodiment, the specific conditions (including the time condition and the product condition) are set in multiple stages. That is, for example, for the time condition, multiple threshold times are set, such as a first threshold time, a second threshold time, a third threshold time, etc., and the control value (pulse width W1) is changed to be larger (longer) each time the elapsed time reaches each threshold time. Similarly, multiple thresholds are set for the product condition. This allows the voltage generating circuit 1 to gradually increase the voltage V0 applied to the discharge electrode 5.

[0082] FIG. 6 is a flowchart showing an example of a representative operation of the control section 22 of the voltage generating circuit 1 according to this embodiment.

[0083] That is, when the voltage generating circuit 1 starts operating, the control unit 22 first sets the control value (pulse width W1) to an initial value that is smaller (shorter) than the optimal value (S1). Next, the control unit 22 determines whether the elapsed time reaches the threshold time (S2). If the elapsed time reaches the threshold time (S2: Yes), the control unit 22 shifts the process to step S4. If the elapsed time does not reach the threshold time (S2: No), the control unit 22 shifts the process to step S3.

[0084] In step S3, the control unit 22 compares the amount of ions generated with a threshold value. If the amount of ions generated is below the threshold value (S3: Yes), the control unit 22 shifts the process to step S4. If the amount of ions generated is not below the threshold value (S3: No), the control unit 22 returns the process to step S2.

[0085] In step S4, the control unit 22 increases the control value (pulse width W1) so as to approach the optimum value, thereby increasing the voltage V0 output from the secondary winding 62, and as a result, the decrease in the amount of ions generated is suppressed.

[0086] Furthermore, the flowchart shown in FIG. 6 is merely an example, and processes may be added or omitted as appropriate, and the order of processes may be changed as appropriate.

[0087] [4] Variations Below, we will list some modified examples of the embodiment 1. The modified examples explained below can be applied in appropriate combinations.

[0088] The specific configuration of the voltage generating circuit 1 is not limited to the configuration shown in Fig. 3, and can be appropriately changed as long as the same function can be realized. For example, the switching element Q1 is not limited to an enhancement type n-channel MOSFET, and may be, for example, an IGBT (Insulated Gate Bipolar Transistor) or the like. Furthermore, one or more processors of the control unit 22 may be realized by a device such as an FPGA (Field-Programmable Gate Array).

[0089] Furthermore, in this embodiment, the specific condition includes both a time condition and a product condition, but is not limited to this, and the specific condition may include only one of a time condition and a product condition.

[0090] Furthermore, the control unit 22 may continuously change the control value (pulse width W1). As an example, the control unit 22 continuously increases the control value (pulse width W1) as the elapsed time increases, thereby continuously increasing the voltage V0 applied to the discharge electrode 5.

[0091] Furthermore, the control unit 22 only needs to be able to control at least one of the pulse width W1 and the period T1 of the primary current I1 as a control value, and may, for example, control only the period T1 of the primary current I1 as a control value.

[0092] Furthermore, it is not essential for the discharge device 10 to generate positive and negative ions, and for example, discharge products other than ions may be generated by the discharge of the first discharge electrode 51 and the second discharge electrode 52. Furthermore, it is not essential for the discharge device 10 to have an induction electrode.

[0093] Further, the discharge device 10 has one each of the first discharge electrode 51 and the second discharge electrode 52, but may have multiple each. The shapes of the first discharge electrode 51 and the second discharge electrode 52 are not limited to brush shapes, and may be, for example, pin-shaped (needle-shaped) or the like.

[0094] (Embodiment 2) The discharge device 10 according to this embodiment differs from the first embodiment in that the period T1 of the primary current I1 can also be controlled as a control value, as shown in Fig. 7. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted as appropriate.

[0095] 7 is an explanatory diagram showing an example of the relationship between the primary current I1 flowing through the primary winding 61 of the transformer 6 and the voltage V0 output from the secondary winding 62 of the transformer 6, with the horizontal axis representing time. Fig. 7 shows a schematic diagram of the change in voltage V0 when the period T1 of the primary current I1 is changed from "small" to "large."

[0096] In this embodiment, the control unit 22 of the pulse generating unit 2 can control not only the pulse width W1 of the primary current I1 but also both the pulse width W1 and the period T1 of the primary current I1 as control values. Here, the control unit 22 can control the pulse width W1 and the period T1 individually.

[0097] In the voltage generating circuit 1 according to this embodiment, the control unit 22 controls the pulse width W1 of the primary current I1 as a “first control value” and controls the period T1 of the primary current I1 as a “second control value.” In other words, the control unit 22 can separately adjust the first control value (pulse width W1), which is a control value, and the second control value (period T1), which is also a control value.

[0098] As described above, the period T1 of the primary current I1 determines the number of times the primary current I1 flows per unit time, and thus determines the number of times discharge occurs at the discharge electrode 5 per unit time, i.e., the frequency of discharge. The smaller (shorter) the period T1 as the second control value, the higher the frequency of discharge, and the larger (longer) the period T1 as the second control value, the lower the frequency of discharge.

[0099] In this embodiment, the control unit 22 of the pulse generating unit 2 also controls the period T1 of the primary current I1 as a control value (second control value). As an example, the period T1 of the primary current I1 is adjusted in the range of 1 / 300 sec or more and 1 / 100 sec or less so that the frequency of the primary current I1 is any value of 100 Hz or more and 300 Hz or less.

[0100] As is clear from FIG. 7, basically, as the period T1 of the primary current I1 becomes larger (longer), the interval between occurrences of the voltage V0 output from the secondary winding 62 of the transformer 6 becomes longer, and the frequency of discharge decreases.

[0101] Incidentally, in the discharge device 10, when a high voltage is applied to the discharge electrode 5, not only ions (positive ions and negative ions) but also ozone may be generated. The amount of ozone generated is approximately proportional to both the voltage V0 applied to the discharge electrode 5 and the frequency of discharge. In other words, basically, the amount of ozone generated increases as the voltage V0 applied to the discharge electrode 5 increases, and the amount of ozone generated also increases as the frequency of discharge increases. Then, as the amount of ozone generated approaches saturation, the rate of increase becomes smaller and it eventually saturates.

[0102] On the other hand, although the amount of ions generated is roughly proportional to the voltage V0 applied to the discharge electrode 5, the effect of the frequency of discharge is small. In other words, basically, the amount of ions generated increases as the voltage V0 applied to the discharge electrode 5 increases, but the amount of ions generated does not change significantly even if the frequency of discharge increases. Furthermore, as the amount of ions generated approaches saturation, the rate of increase becomes smaller and it eventually saturates.

[0103] In short, since ions and ozone have different characteristics with respect to the voltage V0 applied to the discharge electrode 5 and the frequency of discharge, it is possible to appropriately adjust the amount of ions and the amount of ozone generated by individually controlling the pulse width W1 and the period T1.

[0104] Specifically, during a period when the amount of ozone generated is large, the control unit 22 increases (lengthens) the period T1 of the primary current I1, which is the second control value, thereby widening the generation interval of the voltage V0 output from the secondary winding 62 of the transformer 6 and lowering the frequency of discharge. This enables the voltage generating circuit 1 to suppress the amount of ozone generated while suppressing a decrease in the amount of ions generated.

[0105] As an example, in the early stages of use of the discharge device 10 when the discharge electrode 5 is less likely to deteriorate, the control unit 22 keeps the pulse width W1 of the primary current I1 small and shortens (shortens) the period T1 to keep the magnitude A1 of the voltage V0 small and increase the frequency of discharge. Thereafter, as the amount of ozone generated increases, the control unit 22 keeps the pulse width W1 of the primary current I1 small while increasing (lengthening) the period T1 to keep the magnitude A1 of the voltage V0 small and decrease the frequency of discharge. This enables the voltage generating circuit 1 to suppress an increase in the amount of ozone generated.

[0106] Thereafter, when the amount of ions generated decreases with deterioration of the discharge electrode 5, the control unit 22 increases the magnitude A1 of the voltage V0 by increasing the pulse width W1 of the primary current I1. At this time, the control unit 22 may or may not decrease (shorten) the period T1. This enables the voltage generating circuit 1 to suppress the decrease in the amount of ions generated.

[0107] The configuration of the second embodiment (including the modified examples) can be adopted in appropriate combination with the various configurations (including the modified examples) described in the first embodiment.

[0108] (Embodiment 3) The discharge device 10 according to this embodiment differs from the second embodiment in that the period T1 of the primary current I1 is dynamically changed over time. Hereinafter, the same components as those in the second embodiment will be denoted by the same reference numerals and will not be described as necessary.

[0109] That is, in this embodiment, the control unit 22 of the pulse generating unit 2 dynamically changes at least the period T1 as a control value over time. Here, the period T1 of the primary current I1 determines the number of times the primary current I1 flows per unit time, and thus determines the number of times discharge occurs at the discharge electrode 5 per unit time, that is, the frequency of discharge. Therefore, when the period T1 dynamically changes over time, the frequency of discharge also dynamically changes.

[0110] According to this configuration, it is possible to suppress the discharge sound by changing (the frequency of) the discharge sound generated by the discharge electrode 5. For example, when a discharge occurs at a constant period T1, the energy of the period T1 is high and the discharge sound of the period T1 is large, whereas by changing the discharge period T1, the frequency of the discharge sound is dispersed, leading to suppression of the discharge sound.

[0111] Specifically, the control unit 22 randomly switches between a plurality of periods T1 at each predetermined switching time, for example. In this case, it is preferable to set the period T1 to the desired period on average. Since the discharge sound (noise) has high energy at the discharge frequency (reference frequency) and its multiplied frequency, it is preferable to set the switching time to a value that does not match the reciprocal of the multiplied frequency. This allows the frequency characteristics of the discharge sound to be appropriately distributed, and the discharge sound can be effectively suppressed.

[0112] Furthermore, it is preferable that the discharge sound is weighted based on the characteristics of sound sensed by humans (hearing characteristics). That is, since humans have high sensitivity to the frequency band of 1 kHz or more and 2 kHz or less, for example, when the reference frequency is 300 Hz, shortening the period T1 of the primary current I1 and making the discharge frequency higher than the reference frequency (300 Hz) makes the discharge sound more noticeable to humans. Conversely, lengthening the period T1 of the primary current I1 and making the discharge frequency lower than the reference frequency (300 Hz) makes the discharge sound less noticeable to humans.

[0113] However, if the discharge frequency is too low, it will also lead to a decrease in the amount of ions generated, so it is preferable for the control unit 22 to drive with as long a period T1 (frequency: low) as possible while also mixing in short periods T1 (frequency: high).As a result, even if a discharge sound is generated, the frequency changes (randomly), so to people it sounds like white noise, which is less bothersome than a sound with a constant frequency.

[0114] Furthermore, it is also possible to suppress the discharge sound by reducing the pulse width W1 to reduce the voltage V0 output from the secondary winding 62. In comparison with this case, the configuration in which the discharge sound is suppressed by changing the period T1 as in the present embodiment has the advantage that a decrease in the amount of ions generated can be suppressed.

[0115] The configuration of the third embodiment (including the modified examples) can be adopted in appropriate combination with the various configurations (including the modified examples) described in the first or second embodiment.

[0116] [Appendix to the invention] The following will provide an overview of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0117] <Appendix 1> a transformer having a primary winding and a secondary winding; a pulse generating unit for supplying a pulsed primary current to the primary winding, The pulse generating unit has a control unit that controls at least one of a pulse width and a period of the primary current as a control value. Voltage generation circuit.

[0118] <Appendix 2> When the control value when the electrical energy output from the secondary winding per unit time is maximized is set to an optimal value, the control unit sets an initial value of the control value to a value different from the optimal value. 2. The voltage generation circuit of claim 1.

[0119] <Appendix 3> When a specific condition is satisfied, the control unit changes the control value to a side where the electric energy is increased. 3. The voltage generation circuit according to claim 2.

[0120] <Appendix 4> The specific condition includes a time condition regarding an elapsed time. 4. The voltage generation circuit of claim 3.

[0121] <Appendix 5> The specific conditions include product conditions regarding a product obtained by the electrical energy. 5. The voltage generating circuit according to claim 3 or 4.

[0122] <Appendix 6> The control unit is Both the pulse width and the period are controllable as control values, The pulse width and the period can be controlled separately. 6. A voltage generating circuit according to any one of claims 1 to 5.

[0123] <Appendix 7> The control unit dynamically changes at least the period as the control value over time. 7. A voltage generating circuit according to any one of claims 1 to 6.

[0124] <Appendix 8> A voltage generating circuit according to any one of claims 1 to 7; A discharge electrode. Discharge device. [Explanation of symbols]

[0125] 1. Voltage generation circuit 2 Pulse generator 5 Discharge electrode 6. Transformer 10 Discharge device 22 Control section 61 Primary Winding 62 Secondary Winding I1 Primary current T1 period W1 Pulse width

Claims

1. a transformer having a primary winding and a secondary winding; a pulse generating unit for supplying a pulsed primary current to the primary winding, The pulse generating unit has a control unit that controls at least one of a pulse width and a period of the primary current as a control value. Voltage generation circuit.

2. When the control value when the electrical energy output from the secondary winding per unit time is maximized is set to an optimal value, the control unit sets an initial value of the control value to a value different from the optimal value.

2. The voltage generating circuit according to claim 1.

3. When a specific condition is satisfied, the control unit changes the control value to a side where the electric energy is increased.

3. The voltage generating circuit according to claim 2.

4. The specific condition includes a time condition regarding an elapsed time.

4. The voltage generating circuit according to claim 3.

5. The specific conditions include product conditions regarding a product obtained by the electrical energy.

5. A voltage generating circuit according to claim 3.

6. The control unit is Both the pulse width and the period are controllable as the control value, The pulse width and the period can be controlled separately.

5. The voltage generating circuit according to claim 1.

7. The control unit dynamically changes at least the period as the control value over time.

5. The voltage generating circuit according to claim 1.

8. A voltage generating circuit according to any one of claims 1 to 4, A discharge electrode. Discharge device.

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