Voltage generation circuit and discharge device

Abstract

Provided are a voltage generation circuit and a discharge device that are easy to suppress a reduction in the amount of ions generated from a discharge electrode. The voltage generation circuit includes a transformer and a pulse generation unit. The transformer has a primary winding and a secondary winding. The pulse generation unit supplies a pulsed primary current to the primary winding. The pulse generation 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.

Description

Technical Field

[0001] The present invention relates to a voltage generating circuit and a discharge device having a transformer. Background Art

[0002] As a related technology, a voltage generating circuit (high voltage output device) is known that has a transformer (winding transformer) and generates a high voltage on the secondary side of the transformer (for example, see Japanese Patent Publication No. 2008-34174). This voltage generating 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 generating element having two electrodes, thereby generating ions from the ion generating element.

[0003] The voltage generating circuit connects a first terminal connected to the output of the secondary side of the transformer to one electrode of the ion generating element, and connects a second terminal connected to the ground line (reference potential line) to the other electrode of the ion generating element.

[0004] The space between the two electrodes of the ion generating element is open, and the air can freely flow in and out. Thus, a high voltage can be generated between the electrodes to form a discharge state, and ions or ozone can be generated from the air. Summary of the invention

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

[0006] An object of one aspect 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.

[0007] A voltage generating circuit according to one aspect of the present invention includes a transformer and a pulse generating unit. The transformer includes a primary winding and a secondary winding. The pulse generating unit supplies a pulsed primary current to the primary winding. The pulse generating unit includes 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 described above and the discharge electrode described above.

[0009] According to one aspect of 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 It is a schematic perspective view showing the appearance of the discharge device according to the first embodiment. Figure 2 This is a schematic block diagram showing the configuration of the discharge device according to the first embodiment. Figure 3 This is a schematic circuit diagram showing a specific example of the voltage generating circuit according to the first embodiment. Figure 4 This is a schematic explanatory diagram showing an operation example of the voltage generating circuit according to the first embodiment. Figure 5 This is a schematic explanatory diagram showing the amount of ions generated by the discharge device according to the first embodiment. Figure 6 This is a flowchart showing an example of the operation of the control unit of the voltage generating circuit according to the first embodiment. Figure 7 This is a schematic explanatory diagram showing an operation example of the voltage generating circuit according to the second embodiment. DETAILED DESCRIPTION

[0011] The following describes an embodiment of the present invention with reference to the drawings. The following embodiment is only an example of the present invention, and does not limit the technical scope of the present invention.

[0012] (Implementation Method 1) [1] Overall composition First, refer to Figure 1 and Figure 2 The overall structure of the discharge device 10 according to the present embodiment will be described.

[0013] The discharge device 10 includes a voltage generating circuit 1 (see Figure 2 ) and the discharge electrode 5. In the present embodiment, the discharge electrode 5 includes a first discharge electrode 51 and a second discharge electrode 52. The discharge device 10 according to the present embodiment further 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 (the first discharge electrode 51 and the second discharge electrode 52) and the induction electrode. The discharge device 10 applies a voltage to the discharge electrode 5 (the first discharge electrode 51 and the second discharge electrode 52) to generate a discharge between the discharge electrode 5 and the induction electrode, thereby generating positive ions and negative ions as discharge products.

[0015] In the present embodiment, as an example, the discharge device 10 is disposed at a position facing an air passage through which an airflow (wind) generated by an airflow generating device such as a fan passes, and is configured so that at least the first discharge electrode 51 and the second discharge electrode 52 are exposed in the air passage. Thus, the discharge products (positive ions and negative ions) generated by the discharge device 10 are discharged from the blow-out port to a desired space (indoors, etc.) along with the airflow passing through the air passage.

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

[0017] The housing 55 is formed of a resin having electrical insulation properties and is, for example, Figure 1 The housing 55 is a rectangular parallelepiped (box-shaped) having a length in the vertical direction (in the vertical direction). The housing 55 accommodates the electrode substrate 54 and the circuit substrate, etc. A hole for exposing at least the first discharge electrode 51 and the second discharge electrode 52 is formed on one surface of the housing 55.

[0018] The first discharge electrode 51 and the second discharge electrode 52 are provided on the electrode substrate 54 so as to protrude in the 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 a brush-shaped tip. The first discharge electrode 51 and the second discharge electrode 52 protrude from one surface of the electrode substrate 54 to the same height position, and are arranged in a state of being spaced apart in one direction (the length direction of the housing 55).

[0019] In addition, an induction electrode separated 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 substrate housed in the housing 55 has a voltage generating circuit 1. The electrode substrate 54 is electrically connected to the circuit substrate on which the voltage generating circuit 1 is formed. Thus, the voltage generating circuit 1 is electrically connected to the first discharge electrode 51 and the second discharge electrode 52 mounted on the electrode substrate 54. However, the voltage generated by the voltage generating circuit 1 is supplied to the first discharge electrode 51 and the second discharge electrode 52 of the electrode substrate 54 and the induction electrode.

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

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

[0023] In this way, the voltage generating circuit 1 applies a voltage of a magnitude sufficient to generate a discharge between the induction electrode and the first discharge electrode 51 and the second discharge electrode 52 to the discharge electrode 5. Here, positive ions are generated as discharge products from the first discharge electrode 51 as the positive discharge electrode, and negative ions are generated as discharge products from the second discharge electrode 52 as the negative discharge electrode.

[0024] In this embodiment, in particular, Figure 2 As shown, the voltage generating circuit 1 includes a pulse generating unit 2 and a boosting circuit 3 .

[0025] The pulse generator 2 is electrically connected to the input connector 4. The pulse generator 2 receives a supply of a DC voltage from the input connector 4, and applies (outputs) a pulse (impulse) voltage to the booster circuit 3.

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

[0027] The electrode protection part 56 is arranged around the first discharge electrode 51 and the second discharge electrode 52. In the present embodiment, the electrode protection part 56 is formed integrally with the housing 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 higher than the height of the front ends of the first discharge electrode 51 and the second discharge electrode 52.

[0028] The electrode protection part 56 is composed of a pair of frame-shaped members located on both sides of the width direction of the housing 55 with respect to the first discharge electrode 51 and the second discharge electrode 52. Specifically, the electrode protection part 56 is composed of a hollow frame body in 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 Figure 1 Shape shown.

[0029] The partition wall 57 is formed 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 (in the longitudinal direction of the housing 55 in the present embodiment) to partition the space between the first discharge electrode 51 and the second discharge electrode 52. In the present embodiment, the partition wall 57 is formed integrally with the housing 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 front ends of the first discharge electrode 51 and the second discharge electrode 52.

[0030] The discharge device 10 is detachably mounted on a main body of an electrical device such as an air purifier, a heating device, or a cooling device. That is, the discharge device 10 is separate from the main body of the electrical device, and the main body of the electrical device holds the discharge device 10 in a detachable state. Therefore, for example, by removing the discharge device 10 from the main body of the electrical device, maintenance (including inspection, replacement, and repair) of the discharge device 10 is easily performed.

[0031] In addition, in this embodiment, the discharge device 10 has an input connector 4 electrically connected to the voltage generating circuit 1 of the circuit board. The input connector 4 is arranged at one end portion of the housing 55 in the longitudinal direction (at Figure 1 The input connector 4 is detachably connected to a counterpart connector held by a main body of the electric device.

[0032] When the input connector 4 is coupled to the mating connector, the input connector 4 is electrically connected to the mating connector, and the discharge device 10 is electrically connected to the main body of the electrical device. In the present embodiment, as an example, the input connector 4 and the mating connector are plug-in connectors that can be attached and detached along the length direction of the housing 55. Therefore, by sliding the housing 55 along the length direction of the housing 55 from a position facing the mating connector, the input connector 4 can be coupled (electrically connected) to the mating connector.

[0033] [2] Specific structure of voltage generating circuit Next, refer to Figure 3 A specific structure of the voltage generating circuit 1 according to the present embodiment will be described.

[0034] In this embodiment, if Figure 3 As shown in FIG. 1 , the voltage boost circuit 3 of the voltage generating circuit 1 includes a transformer 6. Figure 3As shown, the pulse generator 2 of the voltage generator circuit 1 includes a primary voltage generator 21 , a control unit 22 , and a switching element Q1 . In summary, the voltage generator circuit 1 according to the present embodiment includes the transformer 6 and the pulse generator 2 , and the pulse generator 2 includes the control unit 22 .

[0035] The transformer 6 has a primary winding 61 and a secondary winding 62. The primary winding 61 and the secondary winding 62 of the transformer 6 are magnetically coupled, and when a current (primary current I1) flows through the primary winding 61 to generate a magnetic flux, an induced electromotive force is generated in the secondary winding 62. In the present embodiment, the transformer 6 boosts the voltage applied to the primary winding 61, and generates a boosted voltage V0 between the two ends (the first end 621 and the 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 discharge electrode 51 as a positive discharge electrode and the second discharge electrode 52 as a negative discharge electrode are electrically connected to the first end 621 as one end of the secondary winding 62 via mutually reversed rectifying elements (diodes, etc.). On the other hand, the induction electrode is electrically connected to the second end 622 as the other end of the secondary winding 62.

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

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

[0039] The primary winding 61 of the transformer 6 is electrically connected to the output of the pulse generator 2. The pulse generator 2 supplies a pulsed primary current I1 to the primary winding 61. That is, the pulse generator 2 does not continuously supply current to the primary winding 61, but supplies a pulse having a certain pulse width W1 (see Figure 4 ) is intermittently supplied to the primary winding 61. Thus, relatively small electric energy can be input to the primary winding 61, and a relatively large (high voltage) voltage V0 can be generated in the secondary winding 62 by using the induced electromotive force.

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

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

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

[0043] The switch element Q1 changes the conduction state between the drain and the source according to the gate voltage (gate-source voltage) applied to the control terminal (gate terminal). The drain of the switch element Q1 is connected to the transformer 6 (primary winding 61), and the source is connected to the circuit ground. That is, the drain-source of the switch element Q1 is electrically connected in series with the primary winding 61 of the transformer 6 to form a current path. Therefore, the conduction state between the drain and the source of the switch element Q1 changes, thereby controlling the primary current I1 flowing through the primary winding 61 of the transformer 6.

[0044] The switch element Q1 can basically switch between two states: an on state and an off state. The on state of the switch element Q1 is a state where the drain and source of the switch element Q1 are conducting, and the off state of the switch element Q1 is a state where the drain and source of the switch element Q1 are disconnected. That is, the primary current I1 flows to the primary winding 61 only when the switch element Q1 is in the on state, and the primary current I1 does not flow to the primary winding 61 if the switch element Q1 is in the off state.

[0045] The control unit 22 of the pulse generator 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 conduction state between the drain and the source 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 into a conducting state when the control signal Si1 is at an H (High) level, and turns the switching element Q1 into a disconnected state when the control signal Si1 is at an L (Low) level.

[0046] In this embodiment, the control unit 22 has one or more processors and one or more memories as hardware, and the one or more processors execute programs recorded in the one or more memories, and a computer capable of realizing various functions is used as the main component. The computer referred to in this disclosure includes a microcontroller, which includes one or more processors and one or more memories.

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

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

[0049] In particular, in the control unit 22 mainly composed of a computer such as a microcontroller, it is possible to output an arbitrary control signal Si1 according to a program, so that the pulse width W1 and the period T1 of the primary current I1 can be controlled by software. As a result, the control unit 22 of the pulse generator 2 can control the pulse width W1 and the 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 the present embodiment includes a transformer 6 and a pulse generating unit 2. The transformer 6 includes 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" described in the present disclosure is a value that can be controlled (i.e., set / changed) by the control unit 22, for example, controlled (set / changed) within a preset variable range. The control unit 22 can set any value within the variable range as the "control value", or can set any value selected from a plurality of values ​​set in multiple stages within the variable range as the "control value". 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 does not set at least one of the pulse width W1 and the period T1 of the primary current I1 supplied to the primary winding 61 of the transformer 6 as a fixed value, but can be controlled by the control unit 22. As will be described in detail later, if at least one of the pulse width W1 and the period T1 of the primary current I1 changes, the electric energy output from the secondary winding 62 of the transformer 6 per unit time also changes.

[0053] As an example, the voltage generating circuit 1 can increase the electric energy output from the secondary winding 62 of the transformer 6 and increase the voltage V0 applied to the discharge electrode 5 by controlling the control value. When a long time has passed since the discharge device 10 was used, the amount of ions generated from the discharge electrode 5 may decrease due to the degradation of the discharge electrode 5 (including the adhesion of foreign matter, etc.). For example, in such a case, the voltage generating circuit 1 controls the control value to increase the voltage V0 applied to the discharge electrode 5, increase the amount of ions generated from the discharge electrode 5, and thus can suppress the decrease in the amount of ions generated from the discharge electrode 5. Therefore, according to the voltage generating circuit 1 of this embodiment, there is an advantage that it is easy to suppress the decrease in the amount of ions generated from the discharge electrode 5.

[0054] Furthermore, the voltage generating circuit 1 according to the present embodiment controls the control value on the primary side rather than the secondary side of the transformer 6 generating the high voltage, so that, for example, the control value can be controlled even with a component having a relatively low withstand voltage without switching the high voltage.

[0055] In addition, in the voltage generating circuit 1, the voltage V0 output from the secondary winding 62 can also be changed by controlling the voltage applied to the primary winding 61, but in this 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 the present embodiment, since 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, it is not necessary to switch the output voltage of the pulse generating unit 2, and the circuit structure can be simplified.

[0056] [3] Operation example of voltage generating circuit Next, refer to Figures 4 to 6 An operation example of the voltage generating circuit 1 according to the present embodiment will be described.

[0057] Figure 4 1 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 being the time axis. Figure 4 , a change in the voltage V0 when the pulse width W1 of the primary current I1 is changed from “small” to “large” is schematically shown.

[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 the present embodiment, the control unit 22 controls the pulse width W1 of the primary current I1 as a control value. That is, in the present 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, so that the period T1 of the primary current I1 is fixed (unchanged).

[0059] The “pulse width W1” of the primary current I1 of the present disclosure represents the width (time width) from the moment when the switch element Q1 is turned on to start supplying the primary current I1 to the primary winding 61 to the moment when the switch element Q1 is turned off to stop supplying the primary current I1 to the primary winding 61. That is, Figure 4 As shown, the pulse width W1 is represented by the time from the rise to the fall of the primary current I1, and the unit is, for example, seconds (including microseconds, etc.).

[0060] On the other hand, the “period T1” of the primary current I1 of the present disclosure represents the interval (time interval) from the moment when the switching element Q1 is turned on to start supplying the primary current I1 to the primary winding 61 to the moment when the switching element Q1 is turned on next time to start supplying the primary current I1 to the primary winding 61. That is, Figure 4 As shown, the period T1 is represented by the time from the rise of the primary current I1 to the next rise, and the unit is, for example, seconds (including milliseconds, etc.).

[0061] Here, in the discharge device 10, when the primary current I1 flows through the primary winding 61 of the transformer 6 and the voltage V0 is output from the secondary winding 62, discharge occurs at the discharge electrode 5. Therefore, the period T1 of the primary current I1 specifies the number of times the primary current I1 flows per unit time, and further specifies 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 the present embodiment, as described above, the control unit 22 of the pulse generator 2 keeps the period T1 of the primary current I1 fixed (constant), and controls the pulse width W1 of the primary current I1 as a control value. As an example, the period T1 of the primary current I1 is set to any value greater than 1 / 300 sec and less than 1 / 100 sec, and the frequency of the primary current I1 is set to any value greater than 100 Hz and less than 300 Hz.

[0063] Moreover, by Figure 4 It can be seen that, basically, if 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, if 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] exist Figure 4 In the example of , the magnitude A1 of the voltage V0 is expressed by peak-to-peak. However, similarly, the magnitude of the positive voltage output by the first discharge electrode 51 as the positive discharge electrode and the negative voltage output by the second discharge electrode 52 as the negative discharge electrode change according to the pulse width W1 of the primary current I1.

[0065] That is, if the pulse width W1 increases, the electric power energy (electric energy) supplied to the primary winding 61 of the transformer 6 increases, so the voltage V0 output from the secondary winding 62 of the transformer 6 also increases. On the contrary, if the pulse width W1 decreases, the electric power energy (electric energy) supplied to the primary winding 61 of the transformer 6 decreases, so 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 becomes maximum (peak value) at a certain pulse width W1. In the present invention, within the variable range in which the control value (in this embodiment, the pulse width W1) can be adjusted, the control value (pulse width W1) at which the voltage V0 becomes maximum is defined as the "optimal value". That is, when the pulse width W1 as the control value is the optimal value, the voltage V0 output from the secondary winding 62 is the maximum, and when the pulse width W1 as the control value becomes a value smaller or larger than the optimal value, the voltage V0 output from the secondary winding 62 decreases (becomes smaller).

[0067] Therefore, in the present embodiment, the pulse width W1 as the control value is limited in the adjustment range in such a manner that the optimum value is the upper limit and the control value (pulse width W1) when the voltage V0 output from the secondary winding 62 is appropriately reduced (decreased) is the lower limit. Thus, the control unit 22 can gradually increase (increase) the voltage V0 output from the secondary winding 62 by, for example, gradually increasing the pulse width W1 toward the upper limit within the adjustment range. Furthermore, since the pulse width W1 as the control value does not use a range exceeding the optimum value, the control unit 22 can avoid a decrease in power transmission efficiency caused by the pulse width W1 of the primary current I1 being increased to a value greater than necessary (becoming longer).

[0068] In addition, in the present embodiment, when the control value at which the electric energy output from the secondary winding 62 per unit time becomes maximum 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 the present embodiment, regarding the pulse width W1 as the control value, within the adjustment range with the optimal value as the upper limit as described above, a value smaller (shorter) than the optimal value is set as the initial value of the control value (pulse width W1).

[0069] The "electric energy" mentioned here includes electric energy, which is defined by, for example, voltage V0, current, and time. In the present 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 electric energy becomes maximum is synonymous with the control value when the voltage V0 becomes maximum. In addition, the "initial value" mentioned here is, for example, the value of the control value (pulse width W1 in the present embodiment) set at the start of use of the discharge device 10, that is, at the start of use of the voltage generating circuit 1.

[0070] In summary, in this embodiment, when the discharge device 10 is started to be used, the control unit 22 controls the control value (pulse width W1) to an initial value different from the optimal value at which the voltage V0 output from the secondary winding 62 becomes the maximum. In this embodiment, as an example, the control value (pulse width W1) when the voltage V0 becomes 60% of the maximum value is used as the initial value. Thus, when the discharge device 10 is started to be used, the voltage generating circuit 1 operates in a state in which the voltage VO output from the secondary winding 62 is not in the maximum state but is suppressed to about 60% of the maximum.

[0071] Therefore, for example, as time passes from the start of use of the discharge device 10, the control unit 22 changes the control value (pulse width W1) from the initial value to a value close to the optimal value, thereby increasing the voltage V0 (from 60%) output from the secondary winding 62. As a result, for example, even if the discharge electrode 5 deteriorates (including the adhesion of foreign matter, etc.) over a long period of time from the start of use of the discharge device 10, the voltage generating circuit 1 increases the voltage V0 applied to the discharge electrode 5 and increases 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, if the discharge electrode 5 is deteriorated, Figure 5 As shown by the imaginary line (two-dot chain line) in FIG. 1 , the ion generation amount (ion concentration) decreases with the passage of time from the start of use of the discharge device 10. In contrast, in the voltage generating circuit 1 according to the present embodiment, the control unit 22 increases the voltage V0 applied to the discharge electrode 5 by gradually increasing the control value (pulse width W1). Figure 5 As shown, it is possible to suppress a decrease in the amount of ions generated from the discharge electrode 5 (ion concentration).

[0073] In addition, when a specific condition is satisfied, the control unit 22 changes the control value toward the side where the electric energy becomes larger. In the present 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 used as the initial value of the control value (pulse width W1), so 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" referred to in the present disclosure is an event that is triggered by the control unit 22 changing the control value (pulse width W1) to the side where the electric energy becomes larger, and is pre-specified. According to this configuration, the control unit 22 determines whether the specific condition is met, and can automatically change the control value when the specific condition is met without relying on human operation.

[0075] Specifically, in the present embodiment, the specific condition includes a time condition related to the elapsed time. The "elapsed time" referred to here is, for example, the time elapsed from 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 obtained by accumulating only the period during which the power of the discharge device 10 is turned on (the period during operation), or may be the time calculated without considering whether the power of the discharge device 10 is turned on / off.

[0076] In the present embodiment, as an example, the time condition includes that the elapsed time (set as the accumulated usage time) reaches a predetermined threshold time. That is, 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 by a timer, for example. The elapsed time is recorded in a nonvolatile memory, etc., so that it will not be reset even if the power supply of the discharge device 10 is turned off.

[0077] According to this configuration, for example, even if the discharge electrode 5 deteriorates over a long period of time from the start of use of the discharge device 10, the voltage generating circuit 1 increases the voltage V0 applied to the discharge electrode 5 to 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.

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

[0079] In this embodiment, as an example, the product condition includes that the amount of ions generated as the product (ion concentration) is lower than a predetermined threshold value. That is, when the amount of ions generated is lower than the threshold value, the control unit 22 determines that the specific condition is satisfied, and changes the amount of ions generated so that the control value (pulse width W1) becomes larger (longer). Here, the amount of ions generated (ion concentration) can be measured, for example, by an ion concentration meter (sensor). The amount of ions generated does not need to be measured all the time, but is measured intermittently.

[0080] According to this configuration, for example, even if the discharge electrode 5 deteriorates over a long period of time from the start of use of the discharge device 10 , the voltage generating circuit 1 increases the voltage V0 applied to the discharge electrode 5 to 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 .

[0081] In the present embodiment, the specific conditions (including time conditions and product conditions) are set to multiple levels. That is, for example, regarding the time condition, multiple threshold times are set, such as the first threshold time, the second threshold time, the third threshold time, etc., and each time the elapsed time reaches each threshold time, the control value (pulse width W1) is changed to make it larger (longer). The multiple thresholds are also set for the product conditions. Thus, the voltage generating circuit 1 can gradually increase the voltage V0 applied to the discharge electrode 5.

[0082] Figure 6 This is a flowchart showing an example of a representative operation of the control unit 22 of the voltage generating circuit 1 according to the present embodiment.

[0083] That is, when the voltage generating circuit 1 starts to operate, 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 has reached the threshold time (S2). When the elapsed time has reached the threshold time (S2: Yes), the control unit 22 transfers the process to step S4. If the elapsed time has not reached the threshold time (S2: No), the control unit 22 transfers the process to step S3.

[0084] In step S3, the control unit 22 compares the amount of ion generation with the threshold value. If the amount of ion generation is lower than the threshold value (S3: Yes), the control unit 22 transfers the process to step S4. If the amount of ion generation is not lower than 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 optimal value. As a result, the voltage V0 output from the secondary winding 62 increases, and as a result, the decrease in the amount of ion generation is suppressed.

[0086] in addition, Figure 6 The flowchart shown is merely an example, and processes may be appropriately added or omitted, or the order of processes may be appropriately changed.

[0087] [4] Modifications The following lists modifications of Embodiment 1. The modifications described below can be applied in combination as appropriate.

[0088] The specific structure of the voltage generating circuit 1 is not limited to Figure 3The configuration shown can be appropriately changed as long as the same function can be achieved. For example, the switch element Q1 is not limited to an enhanced n-channel MOSFET, and may be an IGBT (Insulated Gate Bipolar Transistor). In addition, one or more processors of the control unit 22 may be implemented by a device such as an FPGA (Field-Programmable Gate Array).

[0089] In the present embodiment, the specific condition includes both the time condition and the product condition, but the present invention is not limited thereto, and the specific condition may include only one of the time condition and the product condition.

[0090] The control unit 22 may also 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] It is only necessary for the control unit 22 to control at least one of the pulse width W1 and the period T1 of the primary current I1 as a control value. For example, the control unit 22 may control only the period T1 of the primary current I1 as a control value.

[0092] In addition, the discharge device 10 does not necessarily generate positive and negative ions, and for example, discharge products other than ions may be generated by discharge between the first discharge electrode 51 and the second discharge electrode 52. In addition, the discharge device 10 does not necessarily have an induction electrode.

[0093] The discharge device 10 includes one first discharge electrode 51 and one second discharge electrode 52, but may include a plurality of electrodes. The shapes of the first discharge electrode 51 and the second discharge electrode 52 are not limited to brush shapes, and may be pin-shaped (needle-shaped), for example.

[0094] (Implementation Method 2) like Figure 7 As shown, the discharge device 10 according to this embodiment is different from Embodiment 1 in that the period T1 of the primary current I1 can also be controlled as a control value. Hereinafter, the same components as those of Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted as appropriate.

[0095] Figure 7 1 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 being the time axis. Figure 7, a change in the voltage V0 when the period T1 of the primary current I1 is changed from “small” to “large” is schematically shown.

[0096] In this embodiment, the control unit 22 of the pulse generator 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 independently.

[0097] In the voltage generating circuit 1 according to the present embodiment, the control unit 22 controls the pulse width W1 of the primary current I1 to be the "first control value" and controls the period T1 of the primary current I1 to be the "second control value". That is, the control unit 22 can adjust the first control value (pulse width W1) as the control value and the second control value (period T1) as the same control value.

[0098] As described above, the period T1 of the primary current I1 specifies the number of times the primary current I1 flows per unit time, and further specifies the number of times discharges are generated per unit time at the discharge electrode 5, that is, the frequency of discharges. The smaller (shorter) the period T1 as the second control value is, the higher the frequency of discharges is, and the larger (longer) the period T1 as the second control value is, the lower the frequency of discharges is.

[0099] In this embodiment, the control unit 22 of the pulse generator 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 within a range of 1 / 300 sec to 1 / 100 sec of any value of the frequency of the primary current I1 being 100 Hz to 300 Hz.

[0100] Moreover, by Figure 7 Basically, it can be seen that if the period T1 of the primary current I1 becomes larger (longer), the generation interval of the voltage V0 output from the secondary winding 62 of the transformer 6 becomes larger, and the frequency of discharge becomes lower.

[0101] However, in the discharge device 10, by applying a high voltage to the discharge electrode 5, not only ions (positive ions and negative ions) but also ozone is sometimes generated. The amount of ozone generated is roughly proportional to both the voltage V0 applied to the discharge electrode 5 and the frequency of the discharge. That is, basically, if the voltage V0 applied to the discharge electrode 5 becomes larger, the amount of ozone generated increases, and even if the frequency of the discharge becomes higher, the amount of ozone generated increases. Moreover, if the amount of ozone generated approaches the saturation amount, the increase amplitude will become smaller and eventually reach saturation.

[0102] On the other hand, the amount of ions generated is proportional to the voltage V0 applied to the discharge electrode 5, but the frequency of the discharge has little effect. That is, basically, if the voltage V0 applied to the discharge electrode 5 increases, the amount of ions generated increases, but even if the frequency of the discharge increases, the amount of ions generated does not change significantly. Moreover, if the amount of ions generated approaches the saturation amount, the increase will become smaller and eventually reach saturation.

[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, the amount of ions and ozone generated can be appropriately adjusted by individually controlling the pulse width W1 and the period T1.

[0104] Specifically, during a period when the amount of ozone generated is high, the control unit 22 increases (lengthens) the period T1 of the primary current I1 as the second control value to expand the generation interval of the voltage V0 output from the secondary winding 62 of the transformer 6 and reduce the frequency of discharge. Thus, the voltage generating circuit 1 can suppress the reduction in the amount of ion generation and the amount of ozone generation.

[0105] As an example, in the initial use of the discharge device 10 in which the discharge electrode 5 is difficult to deteriorate, the pulse width W1 of the primary current I1 is suppressed to be small and the period T1 is suppressed to be small (shortened), thereby suppressing the magnitude A1 of the voltage V0 to be small and increasing the frequency of discharge. Thereafter, as the amount of ozone generated increases, the control unit 22 increases (lengthens) the period T1 while suppressing the pulse width W1 of the primary current I1 to be small, thereby suppressing the magnitude A1 of the voltage V0 to be small and reducing the frequency of discharge. Thus, the voltage generating circuit 1 can suppress the increase in the amount of ozone generated.

[0106] Then, when the amount of ion generation decreases due to the deterioration of the discharge electrode 5, the control unit 22 increases the magnitude A1 of the voltage VO by increasing the pulse width W1 of the primary current 11. At this time, the control unit 22 can either reduce (shorten) the period T1 or not reduce the period T1. Thus, the voltage generating circuit 1 can suppress the reduction in the amount of ion generation.

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

[0108] (Implementation 3) The discharge device 10 according to this embodiment is different from Embodiment 2 in that the period T1 of the primary current I1 is dynamically changed over time. Hereinafter, the same components as those of Embodiment 2 are denoted by the same reference numerals, and the description thereof is appropriately omitted.

[0109] That is, in this embodiment, the control unit 22 of the pulse generator 2 dynamically changes at least the period T1 as a control value as time passes. Here, the period T1 of the primary current I1 specifies the number of times the primary current I1 flows per unit time, and further specifies the number of times discharges are generated in the discharge electrode 5 per unit time, that is, the frequency of discharges. Therefore, when the period T1 dynamically changes as time passes, the frequency of discharges also dynamically changes.

[0110] According to this configuration, the discharge sound (frequency) generated by the discharge electrode 5 can be changed to suppress the discharge sound. For example, if the discharge is generated at a certain period T1, the energy of the period T1 is high and the discharge sound of the period T1 becomes louder. On the other hand, by changing the discharge period T1, the frequency of the discharge sound is dispersed, resulting in the suppression of the discharge sound.

[0111] Specifically, the control unit 22 randomly switches a plurality of cycles T1 at predetermined switching times, for example. In this case, it is preferably set to a desired cycle T1 on average. Since the discharge sound (noise) has high energy at the discharge frequency (reference frequency) and its multiplication frequency, it is also preferable to set the switching time to a value that is not consistent with the inverse of the multiplication frequency. Thus, the frequency characteristics of the discharge sound are appropriately dispersed, and the discharge sound can be effectively suppressed.

[0112] In addition, it is preferable to weight the discharge sound based on the characteristics of the sound felt by humans (hearing characteristics). That is, humans have high sensitivity in the frequency band above 1 kHz and below 2 kHz. Therefore, for example, when the reference frequency is 300 Hz, if the period T1 of the primary current I1 is shortened and the frequency of the discharge is higher than the reference frequency (300 Hz), the discharge sound is easily transmitted to the human ear. On the contrary, if the period T1 of the primary current I1 is extended and the frequency of the discharge is lower than the reference frequency (300 Hz), the discharge sound is less likely to be transmitted to the human ear.

[0113] However, if the frequency of the discharge is too low, the amount of ions generated will decrease, so it is preferred that the control unit 22 is driven with a period T1 (frequency: low) as long as possible, while also interspersing short periods T1 (frequency: high). Thus, even if a discharge sound is generated, its frequency varies (randomly), so it will sound like white noise to humans and is difficult to detect compared to a sound of a certain frequency.

[0114] Furthermore, the discharge sound can be suppressed by reducing the pulse width W1 to reduce the voltage V0 output from the secondary winding 62. Compared with this case, if the discharge sound is suppressed by changing the period T1 as in the present embodiment, there is an advantage that the reduction in the amount of ion generation can be suppressed.

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

[0116] [Remarks of the invention] Hereinafter, the summary of the invention extracted from the above-mentioned embodiment will be noted. In addition, each configuration and each processing function described in the following remarks can be selected and combined arbitrarily.

[0117] <Note 1> The voltage generating circuit includes: a transformer having a primary winding and a secondary winding; and a pulse generating unit that provides a pulsed primary current to the primary winding, wherein the pulse generating unit has a control unit that controls at least one of the pulse width and period of the primary current as a control value.

[0118] <Note 2> According to the voltage generating circuit described in attachment 1, when the control value at which the electric energy output from the secondary winding per unit time becomes maximum is set to an optimal value, the control unit sets the initial value of the control value to a value different from the optimal value.

[0119] <Note 3> According to the voltage generating circuit described in attachment 2, when a specific condition is satisfied, the control unit changes the control value toward a side where the electric energy increases.

[0120] <Note 4> According to the voltage generating circuit described in attachment 3, the specific condition includes a time condition related to an elapsed time.

[0121] <Note 5> According to the voltage generating circuit described in note 3 or 4, the specific condition includes a product condition related to a product obtained by the electric energy.

[0122] <Note 6> According to the voltage generating circuit described in any one of notes 1 to 5, the control unit can control both the pulse width and the period as the control value, and can control the pulse width and the period separately.

[0123] <Note 7> According to the voltage generating circuit described in any one of attachments 1 to 6, the control unit dynamically changes at least the period as the control value as time passes.

[0124] <Note 8> The discharge device includes: the voltage generating circuit described in any one of Notes 1 to 7; and a discharge electrode.

Claims

1. A voltage generating circuit, characterized in that: include: A transformer having a primary winding and a secondary winding; as well as a pulse generating unit for providing a pulsed primary current to the primary winding; The pulse generating unit includes a control unit configured to control at least one of a pulse width and a period of the primary current as a control value.

2. The voltage generating circuit according to claim 1, characterized in that: When a control value at which electric energy output from the secondary winding per unit time becomes maximum is set as an optimal value, the control unit sets an initial value of the control value to a value different from the optimal value.

3. The voltage generating circuit according to claim 2, characterized in that: When a specific condition is satisfied, the control unit changes the control value toward a side where the electric energy increases.

4. The voltage generating circuit according to claim 3, characterized in that: The specific conditions include a time condition related to an elapsed time.

5. The voltage generating circuit according to claim 3 or 4, characterized in that: The specific conditions include product conditions related to a product obtained by the electric energy.

6. The voltage generating circuit according to any one of claims 1 to 4, characterized in that: The control unit is capable of controlling both the pulse width and the period as the control value, The pulse width and the period can be controlled separately.

7. The voltage generating circuit according to any one of claims 1 to 4, characterized in that: The control unit dynamically changes at least the period as the control value as time passes.

8. A discharge device, characterized in that: include: The voltage generating circuit according to any one of claims 1 to 4; as well as Discharge electrode.

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