Electrical device

Abstract

To realize an electrical device capable of reducing the visibility of flickering in lighting equipment.SOLUTION: An electrical device includes a heater to which an AC voltage is applied, and a control unit that performs zero-cross control of the AC voltage. The control unit controls the AC voltage so that a long-cycle control pattern is repeated as one cycle, the long-cycle control pattern being a sequence of on-periods and off-periods. The long-cycle control pattern includes a first short cycle pattern and a second short cycle pattern. The first short cycle pattern and the second short cycle pattern are made up of sequences of on-periods and off-periods that are different from each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electric device that controls an AC voltage applied to a heater. [Background technology]

[0002] Conventionally, in a power control device, zero-cross control or phase control is used as a method for supplying power to a load. For example, in a power control device disclosed in Patent Document 1, zero-cross control and phase control are used in combination to supply power from an AC power source to a heater. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-167702 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when zero-cross control is used, there is a problem in that, depending on the ratio at which the AC power supply is turned on and off, a flicker phenomenon of brightness that is visible to the eye may occur in lighting equipment that receives power from a power system common to the power control device.

[0005] On the other hand, when phase control is used, the above-mentioned flickering phenomenon does not occur, but the amount of electromagnetic noise generated increases, making it necessary to add components to deal with the electromagnetic noise, which results in a problem of the device becoming larger.

[0006] An object of one embodiment of the present invention is to provide an electric device that can reduce the visibility of flickering caused by a lighting device. [Means for solving the problem]

[0007] In order to solve the above problems, an electric device according to one aspect of the present invention includes a heater to which an AC voltage is applied, and a control unit that performs zero-cross control of the AC voltage applied to the heater in units of half cycles of the AC voltage. The control unit controls the AC voltage in the zero-cross control so that a long-cycle control pattern consisting of an arrangement of an ON period during which the AC voltage is applied to the heater and an OFF period during which the AC voltage is not applied to the heater is set as one cycle, and controls the AC voltage so that the long-cycle control pattern is repeated. The long-cycle control pattern includes a first short-cycle pattern and a second short-cycle pattern. The first short-cycle pattern and the second short-cycle pattern are composed of arrangements of the ON periods and the OFF periods that are different from each other. Effect of the Invention

[0008] According to one embodiment of the present invention, an electrical device capable of reducing the visibility of flickering of a lighting device can be provided. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical cross-sectional view showing an example of an overall configuration of a dryer according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram showing an example of an electrical configuration of the dryer according to the first embodiment. [Diagram 3] 4 is a diagram showing a long-cycle control pattern of an AC voltage applied to a heater of the dryer according to the first embodiment. FIG. [Figure 4] FIG. 4 is a view corresponding to FIG. 3 and relating to Comparative Example 1 of the first embodiment. [Diagram 5] FIG. 11 is a diagram showing a long-period control pattern of an AC voltage applied to a heater of a dryer according to a second embodiment. [Figure 6] 5 according to Comparative Example 2 of the second embodiment. FIG. [Figure 7] FIG. 11 is a diagram showing a long-period control pattern of an AC voltage applied to a heater of a dryer according to a third embodiment. [Figure 8] 7 according to Comparative Example 3 of the third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Embodiment 1] A dryer 1 according to a first embodiment of the present invention will be described with reference to Figs. [Overall configuration of the dryer] First, an example of the overall configuration of a dryer 1 will be described with reference to Fig. 1. Fig. 1 is a vertical cross-sectional view showing an example of the overall configuration of a dryer 1. The dryer 1 is an example of an electric device, and includes a casing 101 as shown in Fig. 1. Hereinafter, for convenience of explanation, the up-down direction of the dryer 1 will be defined as shown by the arrow in Fig. 1.

[0011] Casing 101 is configured to have a cylindrical main body portion 102 and a handle portion 103. Handle portion 103 is provided so as to protrude downward from cylindrical main body portion 102. Handle portion 103 is a portion with which a user grips dryer 1. A power cable 104 for supplying power to dryer 1 from an external power source is attached to the lower portion of handle portion 103.

[0012] An air outlet 102a for blowing out warm air is provided at the front end of the cylindrical main body 102. An air inlet 102b for drawing in outside air is provided at the rear end of the cylindrical main body 102. A nozzle 110 for narrowing the air being blown out is detachably provided at the air outlet 102a.

[0013] Inside main body tube portion 102, there are arranged blower fan 105, motor 106, and heater 107. Motor 106 rotates blower fan 105. When blower fan 105 rotates, an air flow is generated from suction port 102b to air outlet 102a.

[0014] The heater 107 is provided on the outer periphery of the motor 106. An AC voltage is applied to the heater 107 from an AC power source 20 (see FIG. 2). When a predetermined AC voltage is applied to the heater 107, the heater 107 generates heat. When the heater 107 generates heat, the air is heated and is sent out as hot air to the air outlet 102a. The rated current of the heater 107 is, for example, 10 [A]. Note that the above-mentioned numerical value of the rated current of the heater 107 is an example, and the rated current may be greater than 10 [A] or less than 10 [A].

[0015] An insulating sleeve 108 is provided inside the main body tube portion 102 from the motor 106 to the air outlet 102a. The insulating sleeve 108 forms a passage for air generated by the blower fan 105. A power switch 109 is provided on the handle portion 103. The power switch 109 is provided so that the user can switch the power of the dryer 1 on and off. In addition, a control board 100 is provided inside the handle portion 103.

[0016] [Electrical configuration of the dryer] Next, an example of the electrical configuration of the dryer 1 will be described with reference to Fig. 2. Fig. 2 is a circuit diagram showing an example of the electrical configuration of the dryer 1. As shown in Fig. 2, the dryer 1 includes a control unit 10, a zero-cross detection circuit 30, and a triac TR. The dryer 1 is connected to an AC power source 20 via an outlet (not shown).

[0017] The control unit 10 is provided on a control board 100 and includes a microcomputer, etc. Based on the detection result of the zero-cross detection circuit 30, the control unit 10 outputs an ON signal or an OFF signal to the triac TR.

[0018] One end of the AC power supply 20 is connected to the heater 107 of the dryer 1 and the zero-cross detection circuit 30. The other end of the AC power supply 20 is connected to the heater 107 via a triac TR. The AC power supply 20 applies an AC voltage to the heater 107 and the zero-cross detection circuit 30. The frequency of the AC voltage supplied from the AC power supply 20 is, for example, the frequency of a commercial power supply, and is 50 [Hz] or 60 [Hz]. The magnitude of the AC voltage is, for example, 100 [V].

[0019] An input terminal of the zero-cross detection circuit 30 is connected to the AC power supply 20. An output terminal of the zero-cross detection circuit 30 is connected to a zero-cross signal input terminal of the control unit 10. The zero-cross detection circuit 30 is composed of circuit elements such as resistors, diodes, and transistors.

[0020] An AC voltage is supplied from an AC power supply 20 to a zero-cross detection circuit 30. The zero-cross detection circuit 30 detects the timing at which the AC voltage, which is the reference for zero-cross control, becomes 0 [V], and outputs a zero-cross signal indicative of the timing to the control unit 10.

[0021] The triac TR is a semiconductor switching element that is configured by connecting thyristors in inverse parallel, each of which can control a current in one direction, and can control a current in both directions. The triac TR has three terminals: a terminal T1, a terminal T2, and a gate terminal G. The triac TR has a terminal T1 connected to the AC power supply 20, a terminal T2 connected to the heater 107, and a gate terminal G connected to the control unit 10.

[0022] When a trigger voltage is applied to the gate terminal G of the triac TR, one of the thyristors in the triac TR becomes conductive, and a current flows in the direction from terminal T2 to terminal T1 or in the reverse direction, i.e., from terminal T1 to terminal T2.

[0023] [Heater control by the control unit] Next, the control of the heater 107 by the control unit 10 will be described in detail with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing a long-period control pattern of an AC voltage applied to the heater 107 of the dryer 1. Fig. 4 is a diagram corresponding to Fig. 3 and relating to Comparative Example 1 of the first embodiment. Both the first embodiment and Comparative Example 1 are examples in which the heater 107 is operated at an output of 40% (4 / 10) of the maximum output.

[0024] When the user turns on the power switch 109, an AC voltage is applied from the AC power supply 20 to the heater 107. Every time the control unit 10 receives a zero-cross signal, it controls the triac TR to be turned on or off for each half wave, thereby performing zero-cross control of the AC voltage applied to the heater 107 in units of half a cycle of the AC voltage.

[0025] Hereinafter, the half cycle of the AC voltage will be simply referred to as a "half cycle." For example, if the frequency of the AC voltage is 50 Hz, the half cycle is 1 / 100 seconds. In this case, the control unit 10 controls the AC voltage applied to the heater 107 in units of 1 / 100 seconds.

[0026] In the zero-cross control, the control unit 10 controls the AC voltage so that a long-cycle control pattern is repeated, with the long-cycle control pattern being one cycle, as shown in Fig. 3. The long-cycle control pattern is made up of an arrangement of an ON period during which an AC voltage is applied to the heater 107 and an OFF period during which an AC voltage is not applied to the heater 107.

[0027] The long cycle control pattern includes one or more first short cycle patterns and one or more second short cycle patterns. Here, the long cycle control pattern and the short cycle pattern are defined as follows. (1) At the boundary between one long-cycle control pattern and the next, there is always a switch from an off period to an on period. In other words, the long-cycle control pattern starts with an on period and ends with an off period. (2) The short-cycle pattern, like the long-cycle control pattern, begins with an on-period and ends with an off-period. (3) A short cycle pattern is composed of a series of on periods (including one on period) followed by a series of off periods (including one off period). In other words, an off period and a subsequent on period do not belong to one short cycle pattern, but each belong to a different short cycle pattern. That is, the boundary between an off period and a subsequent on period is the boundary of a short cycle pattern.

[0028] Note that the relationship between the on-period and the off-period for the long-cycle control pattern and the short-cycle pattern may be defined inversely to that described above. That is, the long-cycle control pattern may be defined as starting with an off-period and ending with an on-period. In this case, the short-cycle pattern is composed of a series of off-periods (including one off-period) followed by a series of on-periods (including one on-period). The on-period and the subsequent off-period do not belong to one short-cycle pattern, but each belong to a different short-cycle pattern. That is, the boundary between the on-period and the subsequent off-period is the boundary of the short-cycle patterns.

[0029] The first short cycle pattern and the second short cycle pattern are composed of sequences of on and off periods that are different from each other. Specifically, the first short cycle pattern is a waveform that turns on once and then turns off once, i.e., a waveform that turns on for one half cycle and then turns off for one half cycle. On the other hand, the second short cycle pattern is a waveform that turns on once and then turns off twice, i.e., a waveform that turns on for one half cycle and then turns off for two half cycles.

[0030] In the first short cycle pattern, the ratio of the on period to the entire period (2 half cycles) of the first short cycle pattern is both 50%. In the second short cycle pattern, the ratio of the on period (1 half cycle) to the entire period (3 half cycles) of the second short cycle pattern is about 33%, and the ratio of the off period (2 half cycles) to the entire period (3 half cycles) of the second short cycle pattern is about 66%. In other words, in the 2 short cycle pattern, the ratio of the on period to the entire period of the second short cycle pattern is both 20% or more and 80% or less.

[0031] In one cycle of the long cycle control pattern, the first short cycle pattern is repeated twice in succession, and then the second short cycle pattern is repeated twice in succession, i.e., in the long cycle control pattern, both the first short cycle pattern and the second short cycle pattern are repeated twice.

[0032] In the long cycle control pattern, the ratio of the on period (4 half cycles) to the total period (10 half cycles) of the long cycle control pattern is 40%, and the ratio of the off period (6 half cycles) is 60%. Therefore, the heater 107 operates at 40% of the maximum output. In addition, in the long cycle control pattern, neither the on period nor the off period is consecutive before and after the switching between the first short cycle pattern and the second short cycle pattern. In other words, the second off period of the first short cycle pattern is immediately followed by the on period of the second short cycle pattern.

[0033] 4 is a diagram showing a control pattern of an AC voltage applied to a heater of a dryer in Comparative Example 1. The control pattern of Comparative Example 1 is a waveform having four successive on periods followed by six successive off periods, that is, a waveform having four successive on periods for half cycles followed by six successive off periods for half cycles. In the control pattern of Comparative Example 1, the proportion of on periods (4 half cycles) is 40% and the proportion of off periods (6 half cycles) is 60% of the total period (10 half cycles) of the control pattern.

[0034] For example, suppose that the hair dryer of Comparative Example 1 and a lighting device having a light source that is turned on by AC voltage, such as an incandescent light bulb, are connected to a common branch circuit of an AC power supply. In this case, when the hair dryer of Comparative Example 1 is operated, the flickering phenomenon in which the light source of the lighting device repeatedly turns bright and dark is easily visible to humans.

[0035] Specifically, during the on-period of the dryer heater, a relatively large current flows through the heater, causing a voltage drop in the AC voltage in the branch circuit of the AC power supply. Therefore, when comparing the brightness of the lighting device relatively between the on-period and the off-period, the brightness of the lighting device is darker during the on-period than during the off-period (hereinafter referred to as the dark state). In other words, the brightness of the lighting device is brighter during the off-period than during the on-period (hereinafter referred to as the bright state).

[0036] As shown in FIG. 4, in Comparative Example 1, the on-period and the off-period are consecutively arranged in one cycle of the control pattern, so that the dark state in the on-period and the bright state in the off-period are long. In the example shown in FIG. 4, the on-period continues for 4 half cycles, and the off-period continues for 6 half cycles. In other words, in Comparative Example 1, the bright / dark cycle is long, and the bright / dark cycle is 1 / 10 second. Therefore, in Comparative Example 1, it is easier for humans to visually recognize the dark and bright states of the lighting device, and as a result, it is easier to visually recognize the change in brightness of the lighting device as flickering. In other words, the longer the consecutive on-periods or off-periods in one cycle, the easier it is to visually recognize the flickering.

[0037] In contrast, in the dryer 1 of the first embodiment, as shown in Fig. 3, the control pattern of the AC voltage applied to the heater 107 is a long-cycle control pattern including a first short-cycle pattern and a second short-cycle pattern, so that on-periods and off-periods occur multiple times during one cycle of the control pattern. Therefore, in the dryer 1 of the first embodiment, the continuous on-periods and the continuous off-periods are shorter than those in the comparative example 1, even though the output of the heater 107 is the same (40%). As shown in Figs. 3 and 4, the continuous on-period in the first embodiment is one half cycle and the maximum continuous off-period is two half cycles, whereas the continuous on-period in the comparative example 1 is four half cycles and the continuous off-period is six half cycles.

[0038] Therefore, even when the dryer 1 and the lighting device of the first embodiment are connected to a common branch circuit of the AC power supply 20 and the dryer 1 is operated, the period of continuous dark and light states of the lighting device is shorter than that of the first comparative example. In other words, the light and dark cycle of the first embodiment is shorter than that of the first comparative example. The light and dark cycle is about 1 / 50 to 3 / 100 seconds in the first embodiment, whereas it is 1 / 10 seconds in the first comparative example. Therefore, in the first embodiment, it is more difficult for a human being to visually recognize the dark and light states of the lighting device than in the first comparative example, and as a result, it is more difficult to visually recognize the change in light and dark of the lighting device as flicker.

[0039] In addition, in the dryer 1 of the first embodiment, the control unit 10 does not perform phase control, so that the amount of electromagnetic noise generated can be reduced. Therefore, there is no need to add components for dealing with electromagnetic noise, and the dryer 1 can be made smaller.

[0040] [Embodiment 2] Next, a second embodiment of the present invention will be described with reference to Fig. 5 and Fig. 6. For ease of explanation, the same reference numerals are used for members having the same functions as those described in the first embodiment, and the explanations thereof will not be repeated. In the second embodiment, the arrangement of the on-period and off-period in the long-cycle control pattern is different from that in the first embodiment.

[0041] Fig. 5 is a diagram showing a long-cycle control pattern of an AC voltage applied to the heater 107 of the dryer 1 of the second embodiment. Both the second embodiment and the second comparative example (see Fig. 6) are examples in which the heater 107 is operated at an output of about 23% (3 / 13) of the maximum output. As shown in Fig. 5, in the second embodiment, the first short-cycle pattern is a waveform that turns on once and then turns off three times, that is, a waveform that turns on for one half cycle and then turns off for three half cycles. This first short-cycle pattern is then repeated twice in succession in one cycle of the long-cycle control pattern.

[0042] The second short cycle pattern is a waveform that turns on once and then turns off four times, i.e., turns on for one half cycle and then turns off for four half cycles. The second short cycle pattern is included only once in one cycle of the long cycle control pattern. That is, in the long cycle control pattern, only the first short cycle pattern is repeated twice.

[0043] In the first short cycle pattern, the ratio of the on period and the off period to the entire period of the first short cycle pattern are both 20% to 80%. In the second short cycle pattern, the ratio of the on period and the off period to the entire period of the second short cycle pattern are both 20% to 80%.

[0044] In the long-cycle control pattern, the ratio of the on-period to the entire period of the long-cycle control pattern is 20% or more and 80% or less. Also, in the long-cycle control pattern, neither the on-period nor the off-period is consecutive before and after the switching between the first short-cycle pattern and the second short-cycle pattern. In other words, the second off of the first short-cycle pattern is immediately followed by the on of the second short-cycle pattern.

[0045] 6 is a diagram showing a control pattern of an AC voltage applied to a heater of a dryer in Comparative Example 2 of Embodiment 2. In the control pattern of Comparative Example 2, there are three consecutive ONs, i.e., three half cycles, followed by ten consecutive OFFs, i.e., ten half cycles.

[0046] As in Comparative Example 1 (see FIG. 4), in Comparative Example 2, the on-period and the off-period are consecutively grouped together in one cycle of the control pattern as shown in FIG. 6, so that the dark state in the on-period and the bright state in the off-state are long. Therefore, in Comparative Example 2, it is easier for humans to visually recognize the dark and bright states of the lighting device, and as a result, it is easier to visually recognize the change in brightness of the lighting device as flicker.

[0047] In contrast, in the dryer 1 of the second embodiment, as in the first embodiment (see FIG. 3), the control pattern of the AC voltage applied to the heater 107 is a long-cycle control pattern including a first short-cycle pattern and a second short-cycle pattern, as shown in FIG. 5, so that on-periods and off-periods occur multiple times. Therefore, in the dryer 1 of the second embodiment, the continuous time of each of the on-periods and off-periods is shorter than in the comparative example 2, even though the output of the heater 107 is the same (about 23%). Therefore, in the second embodiment, it is more difficult for humans to visually recognize the dark and bright states of the lighting device than in the comparative example 2, and as a result, it is more difficult to visually recognize the change in brightness of the lighting device as flicker.

[0048] [Embodiment 3] Next, a third embodiment of the present invention will be described with reference to Fig. 7 and Fig. 8. For ease of explanation, the same reference numerals are used for members having the same functions as those described in the first embodiment, and the explanations thereof will not be repeated. In the third embodiment, the arrangement of the on-period and off-period in the long-cycle control pattern is different from that in the first embodiment.

[0049] Fig. 7 is a diagram showing a long-cycle control pattern of an AC voltage applied to the heater 107 of the dryer 1 in the third embodiment. Both the third embodiment and the third comparative example (see Fig. 8) are examples of cases in which the heater 107 is operated at an output of 55% (11 / 20) of the maximum output. As shown in Fig. 7, in the third embodiment, the first short-cycle pattern is a waveform that turns on once and then turns off once, that is, a waveform that turns on for one half cycle and then turns off for one half cycle. Moreover, the second short-cycle pattern is a waveform that turns on twice and then turns off once, that is, a waveform that turns on for two half cycles and then turns off for one half cycle.

[0050] The long cycle control pattern is repeated in the following order: the first short cycle pattern twice, the second short cycle pattern once, the first short cycle pattern three times, the second short cycle pattern once, and the first short cycle pattern twice. That is, in the long cycle control pattern, the first short cycle pattern and the second short cycle pattern each occur intermittently.

[0051] In the first short cycle pattern, the ratio of the on period to the entire period of the first short cycle pattern and the ratio of the off period to the entire period of the first short cycle pattern are both 50%. In the second short cycle pattern, the ratio of the on period to the entire period of the second short cycle pattern and the ratio of the off period to the entire period of the second short cycle pattern are both 20% to 80%.

[0052] In the long-cycle control pattern, the ratio of the on-period to the entire period of the long-cycle control pattern is 20% or more and 80% or less. Also, in the long-cycle control pattern, neither the on-period nor the off-period is continuous before and after the switching between the first short-cycle pattern and the second short-cycle pattern. In other words, the arrangement is such that the off-period of the first short-cycle pattern is immediately followed by the on-period of the second short-cycle pattern.

[0053] 8 is a diagram showing a control pattern of an AC voltage applied to a heater of a dryer in Comparative Example 3 of Embodiment 3. The control pattern of Comparative Example 3 is a waveform with 11 consecutive ONs followed by 9 consecutive OFFs, that is, a waveform with 11 half cycles ON followed by 9 half cycles OFF.

[0054] As in Comparative Example 1 (see FIG. 4) and Comparative Example 2 (see FIG. 6), in Comparative Example 3, the on-period and the off-period are consecutively grouped together in one cycle of the control pattern as shown in FIG. 8, so that the dark state in the on-period and the bright state in the off-state are long. Therefore, in Comparative Example 3, it becomes easier for humans to visually recognize the dark state and the bright state of the lighting device, and as a result, it becomes easier to visually recognize the change in brightness of the lighting device as flicker.

[0055] In contrast, in the dryer 1 of embodiment 3, as in embodiment 1 (see FIG. 3) and embodiment 2 (see FIG. 5), the control pattern of the AC voltage applied to the heater 107 is a long-cycle control pattern including a first short-cycle pattern and a second short-cycle pattern, as shown in FIG. 7, so that on periods and off periods occur multiple times. Therefore, in the dryer 1 of embodiment 3, the continuous times of the on periods and off periods are shorter than in comparative example 3, even though the output of the heater 107 is the same (55%).

[0056] Furthermore, in the dryer 1 of the third embodiment, the first short cycle pattern and the second short cycle pattern occur intermittently during one cycle of the long cycle control pattern. In other words, the first short cycle pattern and the second short cycle pattern occur alternately during one cycle of the long cycle control pattern. This makes the continuous time of the on period and the off period shorter, and the periods in which the light and dark (on / off) patterns are the same are not continuous. Therefore, in the third embodiment, it is more difficult for humans to visually recognize the dark and light states of the lighting device compared to the third comparative example, and as a result, it is more difficult to visually recognize the changes in light and dark of the lighting device as flickering.

[0057] In the dryer 1 of the third embodiment, the first short cycle pattern and the second short cycle pattern are present multiple times during one cycle of the long cycle control pattern, and both the first short cycle pattern and the second short cycle pattern occur intermittently, but the configuration is not limited to the above. For example, the dryer 1 may be configured such that only the first short cycle pattern and the second short cycle pattern exist multiple times during one cycle of the long cycle control pattern, and only one of the short cycle patterns occurs intermittently. For example, the dryer 1 may be configured such that only the first short cycle pattern exists multiple times during one cycle of the long cycle control pattern, and the second short cycle pattern exists between the first short cycle pattern and the first short cycle pattern.

[0058] In the dryers 1 of the above-described first to third embodiments, the control unit 10 controls the AC voltage so that different long-cycle control patterns are repeated depending on the strength of the output of the heater 107. That is, in the dryers 1 of the first to third embodiments, it is assumed that different long-cycle control patterns are used depending on the set temperature of the hot air, the ambient air temperature, and the like.

[0059] As described above, in the dryer 1 of the first to third embodiments, as shown in Figs. 3, 5, and 7, the AC voltage applied to the heater 107 is zero-cross controlled by a long-cycle control pattern including a first short-cycle pattern and a second short-cycle pattern, so that an on-period and an off-period occur multiple times in one cycle of the long-cycle control pattern. Therefore, in the dryer 1 of the first to third embodiments, the continuous time of each of the on-period and the off-period is shorter than in the comparative examples 1 to 3 (see Figs. 4, 6, and 8) in which the on-period and the off-period are each grouped so as to be continuous in one cycle of the control pattern. As a result, it becomes difficult for humans to visually recognize the dark and bright states of the lighting equipment, and it becomes difficult to visually recognize the change in brightness of the lighting equipment as flickering.

[0060] Furthermore, in the dryers 1 of the first to third embodiments, the magnitude of the output of the heater 107 can be adjusted by the ratio of the on-period and the off-period of each of the two short cycle patterns (the first short cycle pattern and the second short cycle pattern). Therefore, the dryers 1 of the first to third embodiments can improve the output resolution of the heater 107.

[0061] Furthermore, in the dryers 1 of the first to third embodiments, even when the output of the heater 107 is the same as that in the comparative examples 1 to 3 (see FIGS. 4, 6, and 8) in which the on-periods and the off-periods are arranged so as to be consecutive during one cycle of the control pattern, the visibility of the flickering of the lighting device is reduced. Therefore, in the dryers 1 of the first to third embodiments, the adjustable range of the output of the heater 107 (a range greater than 0% and less than 100%) can be expanded while reducing the visibility of the flickering of the lighting device. Therefore, in the dryers 1 of the first to third embodiments, the heater 107 can be adjusted to a lower or higher output while maintaining low visibility of the flickering of the lighting device.

[0062] In this way, the dryer 1 of the first to third embodiments can achieve a balance between improved output resolution of the heater 107, an expanded output adjustment range of the heater 107, and reduced visibility of flickering of the lighting device.

[0063] Other embodiments In the above-described first to third embodiments, the electric device of the present invention is applied to the dryer 1, but the present invention is not limited to this and may also be applied to other devices such as a heating device or a printing device.

[0064] In the dryer 1 of the above-described embodiments 1 to 3, the control unit 10 uses a triac TR to perform zero-cross control of the AC voltage applied to the heater 107 in half-cycle units, but this is not limited thereto, and the zero-cross control may be performed using multiple transistors instead of the triac TR.

[0065] As described above, the longer the continuous on-period or off-period in one cycle, the easier it is to visually recognize the flicker. Therefore, in the above-mentioned first to third embodiments, in order to reduce the visibility of the flicker, in the first short cycle pattern, the ratio of the on-period and the ratio of the off-period to the entire period of the first short cycle pattern are both 20% or more and 80% or less, and in the second short cycle pattern, the ratio of the on-period and the ratio of the off-period to the entire period of the second short cycle pattern are both 20% or more and 80% or less. In addition, in the long cycle control pattern, the ratio of the on-period and the ratio of the off-period to the entire period are both 20% or more and 80% or less. In order to further reduce the visibility of the flicker of the lighting device, it is preferable that the ratio of the on-period and the off-period to the entire period of each of the first short cycle pattern, the second short cycle pattern, and the long cycle control pattern is set within the above range, that is, 20% or more and 80% or less. Note that the numerical values ​​in the above range (20% or more and 80% or less) are only examples and are not limited to the numerical values.

[0066] However, in at least one of the first short cycle pattern, the second short cycle pattern, and the long cycle control pattern, the ratio of the on period and the off period to the total period may be set outside the above range, i.e., 20% or more and 80% or less. Also, in all of the first short cycle pattern, the second short cycle pattern, and the long cycle control pattern, the ratio of the on period and the off period to the total period may be set outside the above range, i.e., 20% or more and 80% or less.

[0067] For example, in at least one of the first short cycle pattern and the second short cycle pattern, the ratio of the on period and the ratio of the off period to the entire period of one of the patterns may be 20% or more and 80% or less. Specifically, the first short cycle pattern may be a waveform that turns on for one half cycle and then turns off for four consecutive half cycles, and the second short cycle pattern may be a waveform that turns on for one half cycle and then turns off for five consecutive half cycles. In this case, the ratio of the on period to the entire period of the first short cycle pattern is 20% and the ratio of the off period is 80%, and the ratio of the on period to the entire period of the second short cycle pattern is about 17% and the off period is about 83%. In addition, the ratio of the on period to the entire period of the long cycle control pattern is about 18% and the off period is about 82%. Therefore, among the first short cycle pattern, the second short cycle pattern, and the long cycle control pattern, only the first short cycle pattern has a ratio of the on period to the entire period of 20% or more and a ratio of the off period to the entire period of 80% or less.

[0068] Alternatively, the first short cycle pattern may be a waveform that is turned on for one half cycle and then turned off for two consecutive half cycles, and the second short cycle pattern may be a waveform that is turned on for one half cycle and then turned off for five consecutive half cycles. In this case, the ratio of the on period to the entire period of the first short cycle pattern is about 33%, and the ratio of the off period to the entire period of the second short cycle pattern is about 17%, and the ratio of the off period to the entire period of the second short cycle pattern is about 83%. Furthermore, the ratio of the on period to the entire period of the long cycle control pattern is about 22%, and the ratio of the off period to the entire period is about 78%. Therefore, of the first short cycle pattern, the second short cycle pattern, and the long cycle control pattern, the ratio of the on period to the entire period of the first short cycle pattern and the long cycle control pattern is 20% or more and the ratio of the off period to the entire period is 80% or less.

[0069] In addition, in both the first short cycle pattern and the second short cycle pattern, the ratio of the on period to the entire period may be less than 20%. Specifically, the first short cycle pattern may be a waveform that is on for one half cycle and then off for six consecutive half cycles, and the second short cycle pattern may be a waveform that is on for one half cycle and then off for five half cycles. In this case, the ratio of the on period to the entire period of the first short cycle pattern is about 14%, and the ratio of the off period to the entire period of the second short cycle pattern is about 17%, and the ratio of the off period to the entire period of the second short cycle pattern is about 83%. In addition, the ratio of the on period to the entire period of the long cycle control pattern is about 15%, and the ratio of the off period to the entire period is 85%. Therefore, in all of the first short cycle pattern, the second short cycle pattern, and the long cycle control pattern, the on period to the entire period is less than 20%, and the off period is greater than 80%.

[0070] Moreover, as the rated current of the heater 107 increases, the voltage drop of the AC voltage in the branch circuit of the AC power supply increases, making it easier to recognize the flicker. On the other hand, as the rated current of the heater 107 decreases, the voltage drop of the AC voltage in the branch circuit of the AC power supply decreases, making it harder to recognize the flicker. The above-mentioned range of the ratio of the on-period and the off-period (20% or more, 80% or less) in which the flicker is difficult to recognize is an example when the rated current of the heater 107 is 10 [A]. For example, when the rated current of the heater 107 is greater than 10 [A], it is preferable that the range of the ratio of the on-period and the off-period is narrower than the above range (20% or more, 80% or less) (e.g., 25% or more, 75% or less). On the other hand, when the rated current of the heater 107 is less than 10 [A], it is preferable that the range of the ratio of the on-period and the off-period is wider than the above range (20% or more, 80% or less) (e.g., 15% or more, 85% or less).

[0071] 〔summary〕 An electric device according to a first aspect of the present invention includes a heater to which an AC voltage is applied, and a control unit that performs zero-cross control of the AC voltage applied to the heater in units of half cycles of the AC voltage. The control unit controls the AC voltage in the zero-cross control such that a long-cycle control pattern consisting of an ON period during which the AC voltage is applied to the heater and an OFF period during which the AC voltage is not applied to the heater is set as one cycle, and the long-cycle control pattern is repeated. The long-cycle control pattern includes a first short-cycle pattern and a second short-cycle pattern. The first short-cycle pattern and the second short-cycle pattern are composed of mutually different sequences of the ON periods and the OFF periods.

[0072] According to the above configuration, the control unit performs zero-cross control on the AC voltage applied to the heater in half-cycle units of the AC voltage so that the long-cycle control pattern is repeated. The long-cycle control pattern includes a first short-cycle pattern and a second short-cycle pattern, and the first short-cycle pattern and the second short-cycle pattern are composed of different sequences of on-periods and off-periods. This allows control so that the on-periods or off-periods do not continue continuously, thereby preventing flickering in lighting equipment connected to a common AC power source as the electrical equipment. In addition, since no phase control is used, the amount of electromagnetic noise generated can be reduced, and there is no need to add components for electromagnetic noise countermeasures, allowing the device to be made smaller.

[0073] In the electric device according to a second aspect of the present invention, in the above-mentioned first aspect, at least one of the first short cycle pattern and the second short cycle pattern may be repeated a plurality of times in the long cycle control pattern.

[0074] According to the above configuration, in the long-cycle control pattern, at least one of the first short-cycle pattern and the second short-cycle pattern, each consisting of an arrangement of different on periods and off periods, is repeated multiple times, thereby shortening the continuous time of the period during which a voltage drop occurs and the period during which no voltage drop occurs in the AC power supply of the electrical equipment, and thereby effectively preventing flickering of the lighting equipment.

[0075] An electric device according to a third aspect of the present invention is based on the second aspect, and in the long cycle control pattern, at least one of the first short cycle pattern and the second short cycle pattern may occur intermittently.

[0076] According to the above configuration, in the long-cycle control pattern, at least one of the first short-cycle pattern and the second short-cycle pattern occurs intermittently, so that the continuous time of the period during which a voltage drop occurs and the period during which a voltage drop does not occur in the AC power supply of the electrical equipment is shortened, thereby effectively preventing flickering of the lighting equipment.

[0077] An electric device according to a fourth aspect of the present invention is similar to the second aspect, in which both the first short cycle pattern and the second short cycle pattern are repeated a plurality of times in the long cycle control pattern.

[0078] According to the above configuration, in the long-cycle control pattern, the first short-cycle pattern and the second short-cycle pattern, each consisting of an arrangement of different on-periods and off-periods, are repeated multiple times, thereby shortening the continuous time of the period during which a voltage drop occurs and the period during which no voltage drop occurs in the AC power supply of the electrical equipment, and thereby effectively preventing flickering of the lighting equipment.

[0079] In the electric device according to a fifth aspect of the present invention, in the above-mentioned fourth aspect, both the first short cycle pattern and the second short cycle pattern may occur intermittently in the long cycle control pattern.

[0080] According to the above configuration, in the long-cycle control pattern, both the first short-cycle pattern and the second short-cycle pattern occur intermittently, so that the continuous time of the period during which a voltage drop occurs and the period during which no voltage drop occurs in the AC power supply of the electrical equipment is shortened, thereby effectively preventing flickering of the lighting equipment.

[0081] An electrical device according to a sixth aspect of the present invention may be such that, in any one of the first to fifth aspects above, in at least one of the first short cycle pattern and the second short cycle pattern, the proportion of the on period and the proportion of the off period to the total period of the one of the first short cycle pattern and the second short cycle pattern are both 20% or more and 80% or less.

[0082] According to the above configuration, by setting the ratio of the on period and the ratio of the off period to the total period of either the first short cycle pattern or the second short cycle pattern to be between 20% and 80%, the continuous time of the period during which a voltage drop occurs and the period during which a voltage drop does not occur in the AC power supply of the electrical device are shortened, and flickering of the lighting device can be effectively prevented.

[0083] An electrical device according to aspect 7 of the present invention may be such that, in aspect 6 above, in the first short cycle pattern, the proportion of the on period and the proportion of the off period to the total period of the first short cycle pattern are both 20% or more and 80% or less, and in the second short cycle pattern, the proportion of the on period and the proportion of the off period to the total period of the second short cycle pattern are both 20% or more and 80% or less.

[0084] According to the above configuration, it is possible to prevent a continuation of an on period or an off period in the first short cycle pattern and the second short cycle pattern, so that the flickering phenomenon in the lighting device can be effectively suppressed.

[0085] An electrical device according to aspect 8 of the present invention may be configured such that, in any one of aspects 1 to 7 above, in the long-cycle control pattern, the ratio of the on period and the ratio of the off period to the total period of the long-cycle control pattern are both 20% or more and 80% or less.

[0086] According to the above configuration, by setting the ratio of the on period and the ratio of the off period to the entire period of the long-cycle control pattern to be between 20% and 80%, the flickering phenomenon in the lighting device can be effectively suppressed.

[0087] An electrical device according to a ninth aspect of the present invention is any one of the first to eighth aspects above, wherein in the long cycle control pattern, the first short cycle pattern and the second short cycle pattern are continuous, and neither the on period nor the off period need be continuous before or after switching between the first short cycle pattern and the second short cycle pattern.

[0088] According to the above configuration, neither the on period nor the off period is consecutive before or after the switching between the first short cycle pattern and the second short cycle pattern, thereby making it possible to more reliably prevent the flickering phenomenon in the lighting device.

[0089] The electrical device according to a tenth aspect of the present invention may be any one of a dryer, a heating device, or a printing device in any one of the first to ninth aspects described above.

[0090] According to the above configuration, when a dryer, a heating device, or a printing device is used, it is possible to prevent the occurrence of a flickering phenomenon in a lighting device connected to a common AC power source as the device.

[0091] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments. [Explanation of symbols]

[0092] 1. Hair dryer 10 Control section 20 AC power supply 30 Zero-cross detection circuit 107 Heater

Claims

1. a heater to which an AC voltage is applied; a control unit that performs zero-cross control of the AC voltage applied to the heater in units of half cycles of the AC voltage; Equipped with the control unit controls the AC voltage so that a long-cycle control pattern including an ON period during which the AC voltage is applied to the heater and an OFF period during which the AC voltage is not applied to the heater is repeated, the long-cycle control pattern being one cycle in the zero-cross control; The long cycle control pattern includes a first short cycle pattern and a second short cycle pattern, The electric device, wherein the first short cycle pattern and the second short cycle pattern have mutually different sequences of the on-periods and the off-periods.

2. The electric device according to claim 1 , wherein at least one of the first short cycle pattern and the second short cycle pattern is repeated a plurality of times in the long cycle control pattern.

3. 3. The electric device according to claim 2, wherein at least one of the first short cycle pattern and the second short cycle pattern occurs intermittently in the long cycle control pattern.

4. The electric device according to claim 2 , wherein in the long cycle control pattern, both the first short cycle pattern and the second short cycle pattern are repeated a plurality of times.

5. 5. The electric device according to claim 4, wherein in the long cycle control pattern, both the first short cycle pattern and the second short cycle pattern occur intermittently.

6. 2. The electrical device according to claim 1, wherein in at least one of the first short cycle pattern and the second short cycle pattern, the ratio of the on period and the ratio of the off period to the total period of the one of the first short cycle pattern and the second short cycle pattern are both 20% or more and 80% or less.

7. In the first short cycle pattern, a ratio of the on period and a ratio of the off period to a total period of the first short cycle pattern are both 20% or more and 80% or less, 7. The electric device according to claim 6, wherein in the second short cycle pattern, a ratio of the on period and a ratio of the off period to a whole period of the second short cycle pattern are both 20% or more and 80% or less.

8. 2. The electric device according to claim 1, wherein in the long-cycle control pattern, a ratio of the on-period and a ratio of the off-period to a whole period of the long-cycle control pattern are both 20% or more and 80% or less.

9. The electrical device according to claim 1, characterized in that in the long-cycle control pattern, the first short-cycle pattern and the second short-cycle pattern are continuous, and neither the on period nor the off period is continuous before or after switching between the first short-cycle pattern and the second short-cycle pattern.

10. 10. The electrical device according to claim 1, wherein the electrical device is any one of a dryer, a heating device, and a printing device.

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