Power supply device, control program and control method

Abstract

A power supply device for supplying electric power to a capacitive load comprises: a converter, an inverter, a resonant transformer, a detection unit for detecting an output frequency or an output current and an output voltage, and a control unit for controlling the inverter. The control unit calculates the output power, adjusts the output frequency within a predetermined frequency search range, and adjusts the output voltage within a predetermined voltage search range, and determines the minimum value of the output frequency when the output power reaches the predetermined output power as a frequency target value; controls the inverter so that the output frequency becomes the frequency target value, and adjusts the output voltage within a predetermined voltage search range, and determines the value of the output voltage when the output power becomes the target output power as the voltage target value.

Description

Technical Field

[0001] The present invention relates to a power supply device, a control program and a control method. Background Art

[0002] There are known power supply devices that supply power to a capacitive load. For example, Patent Document 1 discloses a power supply device for a discharge tube that converts input AC power into high-frequency AC power and outputs the converted power to a discharge tube as a capacitive load.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 4909209 Summary of the invention

[0006] Problems to be solved by the invention

[0007] As a capacitive load, an ozone generator having a discharge tube for silent discharge is known. The amount of ozone generated is proportional to the amount of discharge of the discharge tube, and the amount of discharge depends on the output voltage and output frequency of the power supply device that drives the ozone generator. If the applied voltage to the discharge tube (i.e., the output voltage of the power supply device) is not above a predetermined value, the discharge tube will not discharge; on the other hand, if the applied voltage to the discharge tube is too high, the insulation of the discharge tube will be damaged. Since the number of discharge tubes is selected according to the amount of ozone generated, the electrostatic capacitance also changes depending on the amount of ozone generated.

[0008] In order to drive such an ozone generator, a high-frequency and high-voltage resonant power supply device is generally used. A high-frequency and high-voltage resonant power supply device usually has a converter, an inverter, and a resonant transformer (leakage transformer). The converter converts the AC power from the commercial AC power supply into DC power. The inverter converts the DC power from the converter into AC power with a higher frequency than the commercial AC power supply. The primary side of the resonant transformer is connected to the inverter, and the secondary side is connected to the ozone generator, which boosts the AC power from the inverter and outputs it.

[0009] Output power P when the ozone generator is driven at frequency f f It can be expressed by formula (1).

[0010]

[0011] C in formula (1) a and C g are the electrostatic capacitances of the gap between the electrodes of the ozone generator and the dielectric part, respectively, v z is the discharge maintenance voltage of the ozone generator, V Pis the output voltage of the power supply. If the specifications of the ozone generator are determined, then C a , C g and v z is a constant. Therefore, the output power P of the power supply device f With the output frequency f and output voltage V P The product is proportional to (P f ∝f×V P ).

[0012] In order to improve the power factor, the power supply device is usually driven at a resonant frequency. The resonant frequency is the difference between the leakage inductance L generated by the transformer coil and the average electrostatic capacitance C when the ozone generator is driven, which is determined by the number of discharge tubes. g (1-V z / V p ) produces a resonant frequency. This resonant frequency f0 can be expressed by equation (2).

[0013]

[0014] Here, consider using a power supply device with a fixed resonant transformer inductance L to cope with changes in the electrostatic capacitance C of the ozone generator. In addition, the amount of ozone generated is proportional to the electrostatic capacitance C. In this case, since the inductance L of the resonant transformer is constant, if the electrostatic capacitance C of the ozone generator changes in response to changes in the amount of ozone generated, the output power P of the power supply device will be f However, if the output power P f If the output frequency is changed, the conduction loss of the inverter and the copper loss of the resonant transformer will change in proportion to the square of the current. And, according to formula (2), the resonant frequency f0 will also change accordingly. If the output frequency is changed according to the resonant frequency f0, the switching loss of the inverter of the power supply device and the iron loss of the resonant transformer will each change in proportion to the output frequency. With respect to the change in the electrostatic capacitance C of the ozone generator, when the losses of the inverter and the resonant transformer change greatly, it is impossible to use a single power supply device to cope with the change in the electrostatic capacitance C of the ozone generator corresponding to the amount of ozone generated.

[0015] Therefore, in the past, it was difficult to realize a power supply device that can set the inductance L of the resonant transformer to be constant and can cope with changes in the electrostatic capacitance C of the capacitive load, that is, it was difficult to realize a highly versatile power supply device that can cope with changes in the specifications of the capacitive load. In the past, it was necessary to design and manufacture the power supply device according to each specification of the capacitive load and fix the output frequency, which became the main reason for the increase in the cost of the power supply device.

[0016] The present invention has been made in view of the above circumstances and has as its object to improve the versatility of a power supply device that supplies electric power to a capacitive load.

[0017] Means for solving problems

[0018] A power supply device according to an embodiment of the present invention supplies power to a capacitive load, and includes:

[0019] a converter that converts alternating current from an AC power source into direct current;

[0020] an inverter that converts the direct current from the converter into alternating current;

[0021] a resonant transformer, which boosts the AC power from the inverter and outputs it to the capacitive load;

[0022] a detection section that detects an output frequency or an output current and an output voltage of the alternating current output to the capacitive load; and

[0023] a control unit that controls the inverter,

[0024] The control unit calculates output power of the alternating current output to the capacitive load based on the detection result of the detection unit,

[0025] The control unit performs a frequency determination process, the frequency determination process is to adjust the output frequency within a predetermined frequency search range, and adjust the output voltage within a predetermined voltage search range, and determine the minimum value of the output frequency when the output power reaches a predetermined output power above a target output power as a frequency target value,

[0026] The control unit performs a voltage determination process, which controls the inverter so that the output frequency becomes the frequency target value, adjusts the output voltage within the predetermined voltage search range, and determines the value of the output voltage when the output power becomes the target output power as the voltage target value.

[0027] A control program according to one embodiment of the present invention is a control program for a power supply device that supplies power to a capacitive load.

[0028] The power supply device comprises:

[0029] a converter that converts alternating current from an AC power source into direct current;

[0030] an inverter that converts the direct current from the converter into alternating current;

[0031] a resonant transformer, which boosts the AC power from the inverter and outputs it to the capacitive load;

[0032] a detection section that detects an output frequency or an output current and an output voltage of the alternating current output to the capacitive load; and

[0033] a control unit that controls the inverter,

[0034] The program causes the power supply device to perform the following steps:

[0035] a step of calculating output power of the alternating current output to the capacitive load based on the detection result of the detection unit;

[0036] The step of adjusting the output frequency within a predetermined frequency search range and adjusting the output voltage within a predetermined voltage search range, and determining the minimum value of the output frequency when the output power reaches a predetermined output power above a target output power as a frequency target value;

[0037] The step of controlling the inverter so that the output frequency becomes the frequency target value, adjusting the output voltage within the predetermined voltage search range, and determining the value of the output voltage when the output power becomes the target output power as the voltage target value.

[0038] A control method according to one embodiment of the present invention is a control method for a power supply device that supplies power to a capacitive load.

[0039] The power supply device comprises:

[0040] a converter that converts alternating current from an AC power source into direct current;

[0041] an inverter that converts the direct current from the converter into alternating current;

[0042] a resonant transformer, which boosts the AC power from the inverter and outputs it to the capacitive load;

[0043] a detection section that detects an output frequency or an output current and an output voltage of the alternating current output to the capacitive load; and

[0044] a control unit that controls the inverter,

[0045] The control method comprises:

[0046] a step of calculating output power of the alternating current output to the capacitive load based on the detection result of the detection unit;

[0047] The steps of adjusting the output frequency within a predetermined frequency search range and adjusting the output voltage within a predetermined voltage search range, and determining the minimum value of the output frequency when the output power reaches a predetermined output power above a target output power as a frequency target value; and

[0048] The step of controlling the inverter so that the output frequency becomes the frequency target value, adjusting the output voltage within the predetermined voltage search range, and determining the value of the output voltage when the output power becomes the target output power as the voltage target value.

[0049] Effects of the Invention

[0050] A power supply device, a control program, and a control method according to an embodiment of the present invention can improve the versatility of a power supply device that supplies power to a capacitive load. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a block diagram showing a schematic configuration of a power supply device according to an embodiment of the present invention.

[0052] Figure 2 This is a flowchart showing the operation of the power supply device.

[0053] Figure 3 It means execution Figure 2 The frequency determination process shown is a flowchart of the operation of the power supply device.

[0054] Figure 4 is a graph showing the relationship between frequency and output power in the frequency determination process.

[0055] Figure 5 It means execution Figure 2 The voltage determination process shown is a flowchart of the operation of the power supply device.

[0056] Figure 6 is a graph showing the relationship between output voltage and output power in the voltage determination process.

[0057] Figure 7 This is a graph showing the relationship between the amount of ozone generated by the ozone generator, the loss in the voltage device, and the reference loss.

[0058] Figure 8 This is a graph showing the relationship between the output frequency and efficiency of a power supply device. DETAILED DESCRIPTION

[0059] Hereinafter, embodiments of the present invention will be described.

[0060] Reference Figure 1 The power supply device 10 according to one embodiment of the present invention is described. The power supply device 10 is used to supply power to a capacitive load. In this embodiment, the capacitive load is described as an ozone generator having a discharge tube for silent discharge, but the capacitive load is not limited to the ozone generator. Figure 1As shown, the power supply device 10 includes a converter 11, a capacitor 12, an inverter 13, a resonant transformer 14, a detection unit 15, a storage unit 16, and a control unit 17. In addition, the input terminal 18 and the output terminal 19 of the power supply device 10 are connected to the commercial power supply and the ozone generator, respectively. Figure 1 In the example shown, the power supply device 10 supports a three-phase AC commercial power supply, but is not limited thereto and may also support a single-phase AC commercial power supply. In addition, the input terminal 18 of the power supply device 10 is not limited to a commercial power supply and may be connected to any AC power supply.

[0061] The converter 11 converts the AC power from the commercial power supply connected to the input terminal 18 into the DC power. The capacitor 12 smoothes the output voltage of the converter 11. The inverter 13 converts the DC power from the converter 11 into a high-frequency AC power with a higher frequency than the commercial power supply. As a switching element of the inverter 13, for example, an IGBT can be used, but it is not limited to this. The primary side of the resonant transformer 14 is connected to the inverter 13, and the secondary side is connected to the ozone generator via the output terminal 19. The resonant transformer 14 boosts the AC power from the inverter 13 and outputs it to the ozone generator via the output terminal 19. As the resonant transformer 14, for example, a leakage transformer can be used, but it is not limited to this.

[0062] The detection unit 15 includes, for example, a frequency detection circuit, a current detection circuit, and a voltage detection circuit. The detection unit 15 is provided in the power supply device 10 and can detect the output frequency f, the output current I, and the output voltage V of the alternating current output from the inverter 13 to the ozone generator via the output terminal 19. P In the present embodiment, the output frequency f of the power supply device 10 is a frequency on the output terminal 19 side relative to the inverter 13. The output current I of the power supply device 10 is a current output from the output terminal 19 to the ozone generator. The output voltage V of the power supply device 10 is P This is a voltage on the output terminal 19 side of the resonance transformer 14 (the secondary side of the resonance transformer 14 ).

[0063] The storage unit 16 has one or more memories. The memory is, for example, a semiconductor memory, a magnetic memory, or an optical memory, but is not limited thereto and may be any memory. The storage unit 16 stores any information used in the operation of the power supply device 10 .

[0064] In the present embodiment, the storage unit 16 stores a predetermined frequency search range and a predetermined voltage search range.

[0065] The predetermined frequency search range is a frequency range determined by taking into account the manufacturing error of the inductance L of the resonant transformer 14 and the manufacturing error of the electrostatic capacitance C of the ozone generator. More specifically, the predetermined frequency search range is a range in which the resonant frequency f0 at which the inductance component of the resonant transformer 14 and the electrostatic capacitance component of the ozone generator resonate due to the manufacturing error is variable, wherein the manufacturing error is the manufacturing error of the inductance L of the resonant transformer 14 and the manufacturing error of the electrostatic capacitance C of the ozone generator. For example, the predetermined frequency search range can be calculated using the manufacturing error range of the inductance L ±ΔL and the manufacturing error range of the capacitance C ±ΔC, or the predetermined frequency range (for example, ±10%) can be calculated using the resonant frequency f0 when the manufacturing error is assumed to be zero as the center.

[0066] The predetermined voltage search range is a voltage range that can be applied to the ozone generating device, which is determined in consideration of the specifications of the ozone generating device and the manufacturing error of the electrostatic capacitance C.

[0067] The predetermined frequency search range and the predetermined voltage search range may be stored in advance in the storage unit 16 , for example, or may be automatically calculated by the control unit 17 and stored in the storage unit 16 .

[0068] The control unit 17 has one or more processors. The processor is, for example, a general-purpose processor or a dedicated processor dedicated to a specific process. The control unit 17 controls the operation of the entire power supply device 10 (for example, the operation of the inverter 13). The details of the operation of the control unit 17 will be described later.

[0069] Here, before describing the operation of the power supply device 10 of the present embodiment, the process by which the inventors completed the present invention is described. As described above, it has been difficult to realize a power supply device that can keep the inductance L of the resonant transformer constant while being able to cope with changes in the capacitance C of the capacitive load. However, the inventors have obtained two new insights described below based on experiments in recent years.

[0070] First insight. It is shown that when the inductance L of the resonant transformer of the power supply device is kept constant, the loss of the power supply device changes very little relative to the change of the electrostatic capacitance C (or the applied generation amount) of the applied ozone generator. In detail, the loss of the power supply device includes a loss component proportional to the frequency (i.e., the switching loss of the inverter and the iron loss + stray load loss of the resonant transformer) and a loss component proportional to the square of the current (i.e., the conduction loss of the inverter and the copper loss of the resonant transformer). For example, if the electrostatic capacitance C (or the applied generation amount) is increased, the resonant frequency becomes lower and the current becomes larger. Figure 7 The figure shows the changes in the various loss components of the power supply device when the amount of ozone generated by the ozone generator is changed within the range of 80% to 120%. Figure 7In the figure, A1 and A2 represent the switching loss and conduction loss of the inverter, respectively, and B1 and B2 represent the iron loss + stray load loss and copper loss of the resonant transformer, respectively. Figure 7 As shown in "A1+A2+B1+B2[%]", the changes in the losses of the inverter and the resonant transformer are very small relative to the changes in the applied generation amount (or electrostatic capacitance C). This provides the idea that the changes in the electrostatic capacitance C of the capacitive load can be coped with while keeping the inductance L of the resonant transformer constant. However, in order to cope with a versatile ozone generator with different electrostatic capacitances C, it is necessary to be able to adjust the output frequency f of the power supply device within a wider frequency range to select an appropriate frequency corresponding to the ozone generator. However, determining the appropriate frequency from a relatively wide frequency range in this way places a heavy workload on the operator, and sometimes it is impossible to determine it. In response to this, as described later, the power supply device 10 according to the embodiment of the present invention can automatically determine the appropriate frequency by what is commonly known as automatic tuning.

[0071] Second insight: It is shown that the power output efficiency of the power supply device is inversely proportional to the output frequency f. Specifically, Figure 8 As shown, there is a strong negative correlation between the output frequency f and the efficiency. It can be seen that when the power supply device is driven by the resonant frequency f0 to achieve the maximum output, the output efficiency of the power supply device may not be the maximum. In contrast, as described later, the power supply device 10 according to the embodiment of the present invention can determine its minimum frequency when reaching the target output power corresponding to the ozone generator through automatic tuning.

[0072] Reference Figure 2 The operation of the power supply device 10 controlled by the control unit 17 will be described.

[0073] Step S100: The control unit 17 stores the predetermined frequency search range and the predetermined voltage search range in the storage unit 16. The predetermined frequency search range and the predetermined voltage search range may be directly input by the operator, or may be automatically calculated by the control unit 17 based on the specification information of the ozone generator and the power supply device 10 respectively input by the operator.

[0074] Step S101: The control unit 17 controls the output frequency f or the output current I and the output voltage V detected by the detection unit 15 based on the detection result of the detection unit 15 (i.e., the output frequency f or the output current I and the output voltage V detected by the detection unit 15). p ) to calculate the output power P f In step S101 and subsequent steps, the control unit 17 can recognize the output power P in real time. f .

[0075] Step S102: The control unit 17 executes a frequency determination process. The details are described later. In general, the frequency determination process is a process of adjusting the output frequency f within a predetermined frequency search range and adjusting the output voltage V within a predetermined voltage search range. p , the output power P f The minimum value of the output frequency f when the predetermined output power is reached is determined as the frequency target value. The predetermined output power is greater than the target output power of the power supply device 10. The predetermined output power may be equal to the target output power, for example. Alternatively, given that the discharge power of the discharge tube of the ozone generator is less than the output power P of the power supply device 10, f In this case, the predetermined output power can also be made greater than the target output power.

[0076] Step S103: The control unit 17 executes a voltage determination process. The details will be described later. In summary, the voltage determination process is the following process: controlling the inverter 13 to make the output frequency f a frequency target value, and adjusting the output voltage V within a predetermined voltage search range. P , the output power P f Output voltage V when reaching the target output power P The value of is determined as the voltage target value.

[0077] Step S104: The control unit 17 sets the output frequency f and the output voltage V P The frequency target value and the voltage target value are maintained to supply power to the ozone generator. Then, the process ends.

[0078] Reference Figure 3 The frequency determination process of step S102 is described in detail. In the present embodiment, a step-by-step incremental tuning method may be used, that is, the frequency target value is determined while the output frequency f is increased by a predetermined value each time, but the method is not limited thereto and any method may be used. In addition, since the intermittent pulses may become interference factors, the control unit 17 performs the frequency determination process while the pulse density is in a state of 100% (full pulse) through the PDM control of the inverter 13. The control unit 17 controls the output voltage V by the PWM control of the inverter 13. P The frequency determination process is performed while making sure that the voltage does not exceed the damage voltage of the ozone generator.

[0079] Step S200: The control unit 17 sets the output frequency f and the output voltage V P In this embodiment, the initial value of the output frequency f is the lower limit of the predetermined frequency search range, and the output voltage V P The initial value of is the lower limit value of the predetermined voltage search range.

[0080] Step S201: The control unit 17 determines the output power Pf Whether the output power P of the power supply device 10 is greater than the target output power (for example, 110% of the target output power). f If the output power has not reached the predetermined value (step S201: No), the process proceeds to step S203. f When the predetermined output power is reached (Yes in step S201 ), the process proceeds to step S202 .

[0081] Step S202: The control unit 17 determines the value of the output frequency f as the frequency target value. Then, the frequency determination process ends, and the process proceeds to the above-mentioned step S103.

[0082] Step S203: The control unit 17 determines whether the search within the predetermined voltage search range has been completed (in this embodiment, the output voltage V P If it is determined that the search within the predetermined voltage search range has been completed (S203 Yes), the process proceeds to step S205. If it is determined that the search within the predetermined voltage search range has not been completed (S203 No), the process proceeds to step S204.

[0083] Step S204: The control unit 17 controls the inverter 13 to change the output voltage V P (In the present embodiment, a predetermined value is increased.) Then, the process returns to step S201.

[0084] Step S205: The control unit 17 determines whether the search within the predetermined frequency search range is completed (in this embodiment, it is determined whether the output frequency f has reached the upper limit value of the predetermined frequency search range). If it is determined that the search within the predetermined frequency search range has been completed (S205 Yes), this is regarded as an error that, for example, the frequency target value cannot be determined, and the processing is completed. If it is determined that the search within the predetermined frequency search range is not completed (S205 No), the processing proceeds to step S206.

[0085] Step S206: The control unit 17 controls the inverter 13 to change the output frequency f (increase the output frequency f by a predetermined value in the present embodiment). Then, the process returns to step S201.

[0086] As described above, the frequency determination process includes the following three processes. The first process (corresponding to steps S200, S201, S203, and S204): while maintaining (fixing) the output frequency f, the output voltage V is changed. P , while determining the output power P f Whether the predetermined output power has been reached; the second process (corresponding to step S202): when it is determined that the output power P fWhen the predetermined output power is reached, the value of the output frequency f at this time is determined as the frequency target value; and the third process (corresponding to step S206): when it is determined that the output power P f If the predetermined output power is not reached, the output frequency f is increased and then the process returns to the first process. Figure 4 As shown, the output power P can be f The minimum value of the output frequency f when the predetermined output power is reached is determined as the frequency target value. In this embodiment, since incremental tuning is adopted, the output frequency can be increased from the lower limit of the predetermined frequency search range to increase the output power P f The value of the output frequency f when the predetermined output power is first reached is determined as the frequency target value.

[0087] Reference Figure 5 The control unit 17 performs the voltage determination process while controlling the pulse density through the PDM control of the inverter 13 so as not to exceed the control upper limit value (for example, 95%) lower than 100%, and at the same time, the voltage determination process is described in detail.

[0088] Step S300: The control unit 17 maintains the output frequency f at the frequency target value.

[0089] Step S301: The control unit 17 sets the output voltage V p Maintained at the initial value (in this embodiment, the lower limit value of the predetermined voltage search range).

[0090] Step S302: The control unit 17 determines the output power P f Whether the target output power has been reached. f If the target output power has not been reached (No in step S302), the process proceeds to step S304. f When the target output power is reached (Yes in step S302 ), the process proceeds to step S303 .

[0091] Step S303: The control unit 17 sets the output voltage V p The voltage determination process is completed and the process proceeds to the above step S104.

[0092] Step S304: The control unit 17 determines whether the search within the predetermined voltage search range has been completed (in this embodiment, the output voltage V pIf it is determined that the search within the predetermined voltage search range has been completed (S304: Yes), the process proceeds to step S306. If it is determined that the search within the predetermined voltage search range has not been completed (S304: No), the process proceeds to step S305.

[0093] Step S305: The control unit 17 controls the inverter 13 to change the output voltage V p (In this embodiment, the predetermined value is increased.) Then, the process returns to step S302.

[0094] Step S306: The control unit 17 increases the upper control limit of the pulse density, for example, by a predetermined amount. Then, the process returns to step S301. Therefore, in the state where the upper control limit of the pulse density is increased, the search within the predetermined voltage search range is performed again.

[0095] By the voltage determination process as described above, Figure 6 As shown, for example, the output power P in the predetermined voltage search range can be f The value of the output voltage when the target output power is reached is determined as the voltage target value. Since the output frequency f is maintained at the frequency target value (i.e., the output frequency f is constant) during the voltage determination process, it can be seen from the above formula (1) that the output power P f With the output voltage V p Proportional relationship.

[0096] As described above, the power supply device 10 according to one embodiment of the present invention adjusts the output frequency f within a predetermined frequency search range and adjusts the output voltage within a predetermined voltage search range when performing the frequency determination process, and adjusts the output power P f The minimum value of the output frequency f when the predetermined output power is reached is determined as the frequency target value; when the voltage determination process is executed, the inverter 13 is controlled to make the output frequency f the frequency target value, and the output voltage is adjusted within the predetermined voltage search range to set the output power P f The value of the output voltage when the target output power is achieved is determined as the voltage target value.

[0097] With this configuration, since the appropriate frequency corresponding to the applied capacitive load is automatically determined from a wide frequency range, the power supply device 10 can cope with the specification variation of the applied capacitive load. Therefore, the versatility of the power supply device for supplying power to the capacitive load is improved. In addition, since the output power P f The minimum value of the output frequency f when the predetermined output power is achieved is determined as the frequency target value, so the output efficiency of the power supply device 10 is improved.

[0098] The present invention is described above based on the accompanying drawings and embodiments, but it should be noted that if a person skilled in the art can easily make various modifications or corrections based on the present disclosure. Therefore, these modifications and corrections are included in the scope of the present invention. For example, it is possible to reconfigure the functions included in each method and step in a logically non-contradictory manner, combine multiple methods and steps into one, or divide them.

[0099] For example, in the above-mentioned embodiment, the following configuration is described: in the voltage determination process executed by the control unit 17 of the power supply device 10, when it is determined in step S304 that the search within the predetermined voltage search range has ended (that is, even if the output voltage V p In the case where the voltage target value cannot be determined even if the voltage target value is increased to the upper limit value of the predetermined voltage search range, the control upper limit value of the pulse density is increased in step S306, and the search is performed again. As another embodiment, for example, when it is determined that the search within the predetermined voltage search range has ended, the search can be continued by increasing the upper limit value of the predetermined voltage search range by a predetermined value.

[0100] In addition, in order to make the power supply device 10 of the above embodiment function, a power supply device that can execute a program can be used. The device can be implemented by storing the following program in the memory of the device, and the processor of the device reads and executes the program, and the program records the processing content for realizing each function of the power supply device 10 of the embodiment. Therefore, the power supply device of one embodiment of the present invention can also be implemented by a program that can be executed by the processor.

[0101] Description of Reference Numerals

[0102] 10 Power supply unit

[0103] 11 Converter

[0104] 12. Capacitor

[0105] 13 Inverter

[0106] 14Resonant Transformer

[0107] 15. Inspection Department

[0108] 16 Storage

[0109] 17 Control Department

[0110] 18 Input terminals

[0111] 19 Output terminals.

Claims

1. A power supply device for supplying electric power to a capacitive load, characterized in that: The power supply device comprises: a converter that converts alternating current from an AC power source into direct current; an inverter that converts the direct current from the converter into alternating current; a resonant transformer, which boosts the AC power from the inverter and outputs it to the capacitive load; a detection unit that detects an output frequency or an output current and an output voltage of the alternating current output to the capacitive load; and a control unit that controls the inverter, The control unit calculates output power of the alternating current output to the capacitive load based on the detection result of the detection unit, The control unit performs a frequency determination process, the frequency determination process is to adjust the output frequency within a predetermined frequency search range and adjust the output voltage within a predetermined voltage search range, and determine the minimum value of the output frequency when the output power reaches a predetermined output power above a target output power as a frequency target value, The control unit performs a voltage determination process, wherein the voltage determination process controls the inverter so that the output frequency becomes the frequency target value, and adjusts the output voltage within the predetermined voltage search range, and determines the value of the output voltage when the output power becomes the target output power as the voltage target value.

2. The power supply device according to claim 1, characterized in that: The frequency determination process comprises: A first process is to determine whether the output power reaches the predetermined output power while changing the output voltage while maintaining the output frequency; The second process is to determine the value of the output frequency as the frequency target value when it is determined that the output power has reached the predetermined output power; as well as A third process is to increase the output frequency and then return to the first process when it is determined that the output power has not reached the predetermined output power.

3. The power supply device according to claim 1 or 2, characterized in that: The control unit performs the frequency determination process in a state where the pulse density is 100% by PDM control of the inverter, and performs the voltage determination process while controlling the pulse density so as not to exceed a predetermined density lower than 100%.

4. The power supply device according to claim 1 or 2, characterized in that: The predetermined frequency search range is a variable frequency range in which the inductance component of the resonant transformer and the electrostatic capacitance component of the capacitive load resonate due to manufacturing errors, wherein the manufacturing errors are manufacturing errors of the inductance of the resonant transformer and manufacturing errors of the electrostatic capacitance of the capacitive load.

5. The power supply device according to claim 1 or 2, characterized in that: The predetermined voltage search range is a voltage range that can be applied to the capacitive load and is determined in consideration of specifications of the capacitive load and manufacturing errors of electrostatic capacitance.

6. A control program product for a power supply device for supplying electric power to a capacitive load, characterized in that: The power supply device comprises: a converter that converts alternating current from an AC power source into direct current; an inverter that converts the direct current from the converter into alternating current; a resonant transformer, which boosts the AC power from the inverter and outputs it to the capacitive load; a detection unit that detects an output frequency or an output current and an output voltage of the alternating current output to the capacitive load; and a control unit that controls the inverter, The control program product enables the power supply device to perform the following steps: a step of calculating output power of the alternating current output to the capacitive load based on the detection result of the detection unit; The step of adjusting the output frequency within a predetermined frequency search range and adjusting the output voltage within a predetermined voltage search range, and determining the minimum value of the output frequency when the output power reaches a predetermined output power above a target output power as a frequency target value; as well as The step of controlling the inverter so that the output frequency becomes the frequency target value, adjusting the output voltage within the predetermined voltage search range, and determining the value of the output voltage when the output power becomes the target output power as the voltage target value.

7. A method for controlling a power supply device for supplying electric power to a capacitive load, characterized in that: The power supply device comprises: a converter that converts alternating current from an AC power source into direct current; an inverter that converts the direct current from the converter into alternating current; a resonant transformer, which boosts the AC power from the inverter and outputs it to the capacitive load; a detection unit that detects an output frequency or an output current and an output voltage of the alternating current output to the capacitive load; and a control unit that controls the inverter, The control method comprises: a step of calculating output power of the alternating current output to the capacitive load based on the detection result of the detection unit; The step of adjusting the output frequency within a predetermined frequency search range and adjusting the output voltage within a predetermined voltage search range, and determining the minimum value of the output frequency when the output power reaches a predetermined output power above a target output power as a frequency target value; as well as The step of controlling the inverter so that the output frequency becomes the frequency target value, adjusting the output voltage within the predetermined voltage search range, and determining the value of the output voltage when the output power becomes the target output power as the voltage target value.

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