Power supply device

Abstract

A power supply device (100) includes a capacitive load (2) and an AC power source (1) that is a voltage source that applies an AC voltage to the capacitive load (2), wherein a series circuit of an inductor (6) and a capacitor (7) is connected to the AC power source (1), a series circuit of a load inductor (5) and the capacitive load (2) is connected in parallel to either the inductor (6) or the capacitor (7), and when the inductance of the inductor (6) is set as Lp, the static capacitance of the capacitor (7) is set as Cp, the inductance of the load inductor (5) is set as Ls, the equivalent static capacitance of the capacitive load (2) is set as Cs, and the frequency of the AC power source is set as fv, the following formulas are satisfied: 0.8 / ((2π·fv)^2) < Lp·Cp < 1.2 / ((2π·fv)^2), and 0.8 / ((2π·fv)^2) < Ls·Cs < 1.2 / ((2π·fv)^2).

Description

Technical Field

[0001] This application relates to power supply devices. Background Technology

[0002] Dielectric barrier discharge has been industrially applied in ozone generators and other applications. However, because it requires generating a discharge, a high-voltage AC waveform needs to be applied to the external environment containing the dielectric. Furthermore, the frequency is as high as kHz to MHz, which significantly impacts the performance of the load. Therefore, a drive circuit that efficiently applies high-frequency, high-voltage signals to the barrier discharge load is needed.

[0003] A power supply device has been disclosed that is designed to connect an inductor in series when driving an ozone generator as a capacitive load with an inverter, wherein the inductor and the equivalent electrostatic capacitance of the ozone generator resonate at the inverter frequency (e.g., Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication WO2005 / 094138 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, in order for the ozone generator to operate properly, there is a lower limit to the power supply voltage, and the circuit constants of the ozone generator as a capacitive load are determined according to the design of the ozone generator.

[0009] Therefore, the device according to Patent Document 1 has the problem that it cannot sufficiently improve the Q value of the resonant circuit.

[0010] This application discloses a technique for solving the aforementioned technical problems, with the aim of generating a high voltage to drive capacitive loads without the need for a transformer by freely designing the Q value of the resonant circuit and increasing the boost ratio.

[0011] Technical solutions for solving technical problems

[0012] The first power supply device disclosed in this application comprises: a capacitive load having an equivalent capacitor and an equivalent resistance; and an AC power supply applying an AC voltage to the capacitive load. The first power supply device is as follows: a series circuit of a first inductor and a first capacitor is connected to the AC power supply, and a series circuit of a load inductor and a capacitive load is connected in parallel to either the first inductor or the first capacitor. Alternatively, the first power supply device is as follows: a parallel circuit of a first inductor and a first capacitor is connected to the AC power supply, and a parallel circuit of a load inductor and a capacitive load is connected in series to either the first inductor or the first capacitor. The first power supply device has the following structure: when the inductance of the first inductor is Lp, the electrostatic capacitance of the first capacitor is Cp, the inductance of the load inductor is Ls, the equivalent electrostatic capacitance of the capacitive load is Cs, and the frequency of the AC power supply is fv, the following equations (6) and (7) are satisfied:

[0013] 0.8 / ((2π·fv)^2)<Lp·Cp<1.2 / ((2π·fv)^2)(6)

[0014] 0.8 / ((2π·fv)^2)<Ls·Cs<1.2 / ((2π·fv)^2)(7).

[0015] The second power supply device disclosed in this application comprises: an inductive load having an equivalent inductor and an equivalent resistance; and an AC power supply applying an AC voltage to the inductive load. The second power supply device is as follows: a parallel circuit of a first inductor and a first capacitor is connected to the AC power supply, and a parallel circuit of a load capacitor and an inductive load is connected in series with either the first inductor or the first capacitor. Alternatively, the second power supply device is as follows: a series circuit of a first inductor and a first capacitor is connected to the AC power supply, and a series circuit of a load capacitor and an inductive load is connected in parallel with either the first inductor or the first capacitor. The second power supply device has the following structure: when the inductance of the first inductor is Lp, the capacitance of the first capacitor is Cp, the capacitance of the load capacitor is Cs, the inductance of the inductive load is Ls, and the frequency of the AC power supply is fv, the following equations (6) and (7) are satisfied:

[0016] 0.8 / ((2π·fv)^2)<Lp·Cp<1.2 / ((2π·fv)^2)(6)

[0017] 0.8 / ((2π·fv)^2)<Ls·Cs<1.2 / ((2π·fv)^2)(7).

[0018] The third power supply device disclosed in this application comprises: a capacitive load having an equivalent capacitor and an equivalent resistance; and an AC power supply applying an AC voltage to the capacitive load. The third power supply device is a power supply device in which a series circuit of a first inductor and a first capacitor is connected to the AC power supply, and n is an integer greater than or equal to 2; a series circuit of an nth inductor and an nth capacitor is connected in parallel to either an (n-1)th inductor or an (n-1)th capacitor; a series circuit of a load inductor and a capacitive load is connected in parallel to either an nth inductor or an nth capacitor; and the third power supply device has the following structure: the resonant frequency of the first inductor and the first capacitor, the resonant frequency of the second inductor and the second capacitor, ..., the resonant frequency of the nth inductor and the nth capacitor are the same as the resonant frequency of the load inductor and the capacitive load, so that the frequency of the AC power supply is the same as the resonant frequency.

[0019] Invention Effects

[0020] According to the first and third power supply devices disclosed in this application, the Q value of the resonant circuit can be freely designed to increase the boost ratio and generate a high voltage to drive capacitive loads without the need for a transformer.

[0021] According to the second power supply device disclosed in this application, the Q value of the resonant circuit can be freely designed to improve the current amplification rate and generate a high current to drive the inductive load without the need for a transformer. Attached Figure Description

[0022] Figure 1 This is a structural diagram of a power supply device that uses an AC voltage source and a series resonant circuit to drive a capacitive load according to Embodiment 1.

[0023] Figure 2 This is another structural diagram of the power supply device that drives a capacitive load using an AC voltage source and a series resonant circuit according to Embodiment 1.

[0024] Figure 3 This is another structural diagram of the power supply device that drives a capacitive load using an AC voltage source and a series resonant circuit according to Embodiment 1.

[0025] Figure 4 This is a structural diagram of a power supply device that drives two capacitive loads using an AC voltage source and a series resonant circuit, according to Embodiment 1.

[0026] Figure 5 This is a structural diagram of a power supply device that drives a capacitive load using an AC voltage source and a multi-stage series resonant circuit, according to Embodiment 1.

[0027] Figure 6 This is a structural diagram of a power supply device for driving an inductive load using an AC voltage source and a series resonant circuit, according to Embodiment 2.

[0028] Figure 7 This is a structural diagram of a power supply device for driving an inductive load using an alternating current source and a parallel resonant circuit, according to embodiment 3.

[0029] Figure 8 This is another structural diagram of the power supply device for driving an inductive load using an alternating current source and a parallel resonant circuit, according to embodiment 3.

[0030] Figure 9 This is another structural diagram of the power supply device for driving an inductive load using an alternating current source and a parallel resonant circuit, according to embodiment 3.

[0031] Figure 10 This is a structural diagram of a power supply device that uses an AC current source and a parallel resonant circuit to drive two inductive loads according to embodiment 3.

[0032] Figure 11 This is a structural diagram of a power supply device that uses an AC current source and a parallel resonant circuit to drive a capacitive load according to embodiment 3.

[0033] Figure 12 This is a structural diagram of a power supply device that uses an IGBT (Insulated Gate Bipolar Transistor) to form an AC voltage source, as described in Embodiment 4.

[0034] Figure 13 This is a structural diagram of a power supply device that uses a MOSFET (metal-oxide-semiconductor field-effect transistor) to form an AC voltage source, as described in Embodiment 4.

[0035] Figure 14 This is a structural diagram of a power supply device that uses thyristors to form an AC current source, as described in Embodiment 4.

[0036] Figure 15 This is a structural diagram of a power supply device that uses IGBTs to form an AC current source, as described in Embodiment 4.

[0037] Figure 16 This is a structural diagram of a power supply device equipped with an inductor adjustment circuit according to embodiment 5.

[0038] Figure 17 This is a structural diagram of a power supply device equipped with a capacitor regulation circuit according to embodiment 5.

[0039] Figure 18 This is a structural diagram of a power supply device that controls the voltage of a capacitive load according to embodiment 7.

[0040] Figure 19This is a structural diagram of a power supply device for controlling the current of a capacitive load according to embodiment 7.

[0041] Figure 20 This is a structural diagram of a power supply device that controls the power supply based on the current of the AC power supply according to embodiment 7.

[0042] Figure 21 This is a structural diagram of a power supply device for controlling the voltage and current of an AC power supply according to embodiment 7.

[0043] Figure 22 This is a structural diagram of a power supply device for embodiment 8 that controls power based on pre-saved optimal operating conditions.

[0044] Figure Labels

[0045] 100, 101, 102, 103, 104, 200, 300, 301, 302, 303, 304, 400, 401, 402, 403, 500, 501, 701, 702, 703, 704, 800: Power supply device; 1: AC power supply; 1A, 1B: AC voltage source; 12: AC power supply; 12A, 12B: AC current source; 2: Capacitive load; 3: Equivalent capacitor; 4: Equivalent resistance; 5: Load inductor; 6: Inductor; 7: Capacitor; 8: Inductive load; 9: Equivalent inductor; 10: Equivalent resistance; 11: Load capacitor; 13, 13A, 13B, 13C, 13D, 13E: Control circuit; 14: Constant voltage source; 15: Capacitor; 16: Constant current source; 17, 18: Inductor 19: Voltage detector; 20: Current detector; 21: Load circuit; 30, 32: Full-bridge inverter; 31: Half-bridge inverter; 40: Regulation mechanism; 41: Regulation mechanism; 50: Storage unit; 321: Load circuit; 2a, 2b: Capacitive load; 3a, 3b: Equivalent capacitor; 4a, 4b: Equivalent resistance; 5a, 5b: Load inductor; 8a, 8b: Inductive load; 9a, 9b: Equivalent inductor; 10a, 10b: Equivalent resistance; 11a, 11b: Load capacitor; 5A: Variable load inductor; 11A: Variable load capacitor; L1: First inductor; Ln-1: (n-1)th inductor; Ln: nth inductor; C1: First capacitor; Cn-1: (n-1)th capacitor; Cn: nth capacitor. Detailed Implementation

[0046] Implementation method 1.

[0047] Embodiment 1 relates to a power supply device that includes a capacitive load and an AC power supply as a voltage source for applying an AC voltage to the capacitive load. The power supply device has the following structure: a series circuit of a first inductor and a first capacitor is connected to the AC power supply; a series circuit of a load inductor and a capacitive load is connected in parallel to either the first inductor or the first capacitor; the resonant frequency of the first inductor and the first capacitor is the same as the resonant frequency of the load inductor and the capacitive load; and the frequency of the AC power supply is the same as the resonant frequency.

[0048] In addition, in Embodiment 1, the cases of driving an inductive load and constructing a multi-stage resonant circuit will also be described.

[0049] The following is a structural diagram of a power supply device that uses an AC voltage source and a series resonant circuit to drive a capacitive load. Figures 1-3 The structural diagram of a power supply device driving two capacitive loads is as follows: Figure 4 And a structural diagram of a power supply device that uses an AC voltage source and a multi-stage series resonant circuit to drive a capacitive load. Figure 5 The structure and operation of the power supply device in Embodiment 1 will be explained.

[0050] based on Figure 1 The basic structure of the power supply device 100 in Embodiment 1 is explained. Additionally, refer to [reference needed] as appropriate. Figure 2 , Figure 3 The basic structural diagram of the power supply device 100 is as follows: Figure 1 A variation of the above.

[0051] The power supply device 100 includes an AC power supply 1, a capacitive load 2, a load inductor 5 that forms a resonant circuit with the capacitive load 2, and an inductor 6 and a capacitor 7 used to amplify the Q value of the resonant circuit. Here, the inductor 6 and the capacitor 7 are the first inductor and the first capacitor as claimed.

[0052] Furthermore, the Q value of the resonant circuit will be explained later.

[0053] In Implementation Method 1, it is assumed that AC power source 1 is a voltage-type AC power source, i.e., an AC voltage source. Voltage-type AC power sources and current-type AC power sources will be explained later.

[0054] The capacitive load 2 corresponds to, for example, an ozone generator and a barrier discharge lamp. This capacitive load 2 is the load that the AC power supply 1 drives. The equivalent circuit of the capacitive load 2 is represented by an equivalent capacitor 3 as the capacitive component and an equivalent resistor 4 as the resistive component.

[0055] Although Figure 1 The equivalent capacitor 3 and the equivalent resistance 4 are represented in series, but sometimes they may be represented as follows: Figure 2It is more appropriate to represent it in parallel. In addition, there may sometimes be both a resistive component connected in series with the equivalent capacitor 3 and a resistive component connected in parallel with the equivalent capacitor 3.

[0056] In addition Figure 2 In order to cooperate with Figure 1 The power supply device 100 is distinguished and is designated as power supply device 101.

[0057] Although there are slight differences in the circuitry, the processing methods are not significantly different. Therefore, regarding capacitive load 2, as... Figure 1 Therefore, it is explained that the equivalent capacitor 3 and the equivalent resistor 4 are connected in series.

[0058] Here, let the equivalent electrostatic capacitance of the equivalent capacitor 3 be Cs, and let the resistance of the equivalent resistor 4 be RL.

[0059] The equivalent electrostatic capacitance Cs and equivalent resistance RL are determined based on the physical operation of the capacitive load 2 and generally vary over time. However, their average values ​​can be used when processing the circuit.

[0060] For example, as described in Patent Document 1, the equivalent electrostatic capacitance Cs or equivalent resistance value RL defined here is such an equivalent average value.

[0061] When driving capacitive load 2 in a series resonant manner, an inductor is connected in series. Figure 1 The load inductor 5 is an inductor used for series resonance. Here, let the inductance of the load inductor 5 be Ls.

[0062] In this application, in addition to the above, the inductor 6 and capacitor 7 are as follows: Figure 1 It is connected in series with AC power supply 1. Here, let the inductance of inductor 6 be Lp, and the capacitance of capacitor 7 be Cp.

[0063] In the sense of load as observed from AC power supply 1, the circuit including the capacitive load 2 and including the inductor 6 (inductor Lp), capacitor 7 (static capacitance Cp), and load inductor 5 (inductor Ls) constituting the resonant circuit of this application is described as load circuit 21.

[0064] Furthermore, in implementation method 1, in Figure 2 The diagrams of the circuit corresponding to load circuit 21 are omitted from hereafter.

[0065] The operating characteristic of the load circuit 21 is that the resonant circuit has two stages.

[0066] That is, the first-stage resonant circuit is formed by the inductor 6 and the capacitor 7 connected in series to the AC power supply 1. The second-stage resonant circuit is formed by the series circuit of the capacitive load 2 connected in parallel to the capacitor 7 and the load inductor 5.

[0067] The following explanation will focus on the case where the resonant frequencies of the first-stage resonant circuit (the series circuit of inductor 6 and capacitor 7) and the second-stage resonant circuit (the series circuit of capacitive load 2 and load inductor 5) are both consistent with the frequency fv of the AC power supply 1, i.e., the case where equation (1) holds. Furthermore, let the frequency of the AC power supply 1 be fv.

[0068] Ls·Cs=Lp·Cp=1 / ((2π·fv)^2) (1)

[0069] The impedances of the load inductor 5 and the equivalent capacitor 3 of the capacitive load 2 are canceled out. The apparent impedance of the series circuit of the load inductor 5, the equivalent resistor 4, and the equivalent capacitor 3 is only the equivalent resistance value RL of the equivalent resistor 4.

[0070] In this case, it is equivalent to the following circuit: inductor 6 and capacitor 7 are connected in series to AC power supply 1, and the equivalent resistor 4 is connected in parallel to capacitor 7.

[0071] Furthermore, according to equation (1), inductor 6 and capacitor 7 also reach the resonance condition, so only the equivalent resistance 4 can be seen from AC power supply 1.

[0072] In other words, AC power supply 1 has a power factor of 1, enabling it to drive at the highest efficiency.

[0073] The load circuit 21 is characterized by its ability to freely design the boost ratio. This feature will be explained below.

[0074] Here, we first consider the case of a series resonant circuit in which a typical inductor (let the inductance be L), a capacitor (let the electrostatic capacitance be C), and a resistor (let the resistance value be R) are driven at the resonant frequency f0 (angular frequency ω0). The relationship is expressed by equation (2).

[0075] ω0=2π·f0=1 / (√(L·C)) (2)

[0076] In addition, its Q value is represented by equation (3).

[0077] Q=(1 / R)·(√(L / C))=(ω0·L) / R=1 / (ω0·C·R) (3)

[0078] Here, capacitive load 2 is the driven object, and its equivalent circuit constants, namely the equivalent electrostatic capacitance Cs of equivalent capacitor 3 and the equivalent resistance RL of equivalent resistor 4, cannot be changed. Furthermore, the frequency of AC power supply 1 can be finely adjusted, but because it significantly affects the performance of capacitive load 2, it cannot be changed drastically.

[0079] Therefore, the Q value of the resonant circuit of capacitive load 2 and load inductor 5 is uniquely determined by equation (3). The Q value is the maximum value of the boost ratio, which is the maximum value of the ratio of the voltage of capacitive load 2 (in this case, the voltage applied to the equivalent capacitor 3) to the power supply voltage.

[0080] When the frequency of AC power supply 1 is changed from the resonant frequency f0, the boost ratio becomes less than the Q value of equation (3). That is, if the frequency of AC power supply 1 is determined according to the operating conditions of capacitive load 2, the Q value of the resonant circuit of capacitive load 2 and load inductor 5 is uniquely determined, and the boost ratio is determined by this resonant circuit.

[0081] On the other hand, in such Figure 1 With that circuit structure, the boost ratio can be freely designed by adding an inductor 6 and a capacitor 7.

[0082] That is, when the load conditions (the electrostatic capacitance Cs of the equivalent capacitor 3 and the equivalent resistance RL of the equivalent resistor 4) and the driving conditions (the frequency of the AC power supply 1) are fixed, the inductance Ls of the load inductor 5 is determined according to equation (1) under resonant conditions. Therefore, the Q value of the resonant circuit of the capacitive load 2 and the load inductor 5 cannot be changed.

[0083] However, the inductance Lp of inductor 6 and the electrostatic capacitance Cp of capacitor 7 can be freely determined within the range of satisfying equation (1).

[0084] The voltage applied to capacitive load 2, also known as the boost ratio, is the product of the boost ratio of the first-stage resonant circuit (the resonant circuit of inductor 6 and capacitor 7) and the boost ratio of the second-stage resonant circuit (the resonant circuit of capacitive load 2 and load inductor 5). The voltage applied to capacitive load 2 can be freely designed.

[0085] Because Figure 1 In the circuit, the inductor 6 and capacitor 7 in the first stage function equivalently under resonant conditions, so they can be interchanged to form a circuit like this. Figure 3 That kind of structure.

[0086] In addition Figure 3 In order to cooperate with Figure 1 The power supply device 100 is distinguished and designated as power supply device 102.

[0087] This is suitable for situations where it is desired to reliably bring the potential on the high-voltage side (the high-voltage side of capacitive load 2) to zero when the power supply is interrupted. To illustrate this, in... Figure 3 The GND potential is specifically recorded in the document.

[0088] Next, based on Figure 4 This section describes the scenario where two capacitive loads are driven simultaneously by a single AC power supply. Here... Figure 4 In order to cooperate with Figure 1 The power supply device 100 is distinguished and is designated as power supply device 103.

[0089] The power supply device 103 includes: an AC power supply 1, two capacitive loads 2a and 2b, load inductors 5a and 5b that form a resonant circuit with each capacitive load 2a and 2b, and an inductor 6 and a capacitor 7 used to amplify the Q value of the resonant circuit.

[0090] Capacitive load 2a has an equivalent capacitor 3a and an equivalent resistance 4a. Capacitive load 2b has an equivalent capacitor 3b and an equivalent resistance 4b.

[0091] Here, the capacitive load 2b and the load inductor 5b are the second capacitive load and the second load inductor as claimed.

[0092] Figure 4 It has the feature of being able to drive two capacitive loads 2a and 2b simultaneously with one AC power supply 1. The capacitive loads 2a and 2b can be the same or different.

[0093] When the circuit constants are different, the load inductors 5a and 5b for resonance need to be designed respectively to satisfy equation (1). The equivalent resistance values ​​of the capacitive loads 2a and 2b can be different.

[0094] Similar to the previous power supply units 100 to 102, in this power supply unit 103, GND can be located anywhere. However, since there are multiple capacitive loads 2a and 2b, it is generally as follows: Figure 4 The point shown is the connection point between capacitive load 2a and capacitive load 2b.

[0095] If the equivalent electrostatic capacitances of capacitive load 2a and capacitive load 2b are equal, and the values ​​of load inductor 5a and load inductor 5b are the same, the circuit can be simplified by setting a common inductor.

[0096] That is, if a common inductor is provided on the path from the connection point of inductor 6 and capacitor 7 to the connection point of capacitive load 2a and capacitive load 2b, then load inductor 5a and load inductor 5b can be shared using a single inductor. As a result, miniaturization and cost reduction can be achieved.

[0097] However, in such Figure 4 When the connection point of capacitive load 2a and capacitive load 2b is at GND potential, the potential of the connection point of inductor 6 and capacitor 7 and the potential of AC power supply 1 change under high voltage due to this structure.

[0098] Next, based on Figure 5 A power supply device using a resonant circuit with multiple stages of inductors and capacitors is described here. Figure 5 In order to cooperate with Figure 1 The power supply device 100 is phase-separated and is designated as power supply device 104.

[0099] exist Figure 1 The LC resonant circuit in the power supply device 100 is a two-stage circuit, but it can also be made into a structure with three or more stages.

[0100] The power supply device 104 includes an AC power supply 1, a capacitive load 2, a load inductor 5 that forms a resonant circuit with the capacitive load 2, and a first inductor L1, a first capacitor C1, ..., an (n-1)th inductor Ln-1, an (n-1)th capacitor Cn-1, an nth inductor Ln, and an nth capacitor Cn used to amplify the Q value of the resonant circuit. Here, n is an integer greater than or equal to 2.

[0101] Here, the first inductor L1 and the first capacitor C1 constitute the first resonant circuit, ..., the (n-1)th inductor Ln-1 and the (n-1)th capacitor Cn-1 constitute the (n-1)th resonant circuit, and the nth inductor Ln and the nth capacitor Cn constitute the nth resonant circuit.

[0102] Furthermore, in order to form a multi-stage structure and to summarize the records, the first inductor is referred to as L1 and the first capacitor as C1.

[0103] By adjusting the resonant frequencies of each stage of the LC resonant circuit in accordance with equation (1), it is possible to obtain... Figure 1 The power supply device 100 described herein has a further improved boost ratio.

[0104] In addition Figure 5 For example, in a series circuit, the first capacitor C1 of the first inductor L1 and the first capacitor C1 is connected in parallel with the second inductor L2 and the second capacitor C2. However, as... Figure 1 and Figure 3 As explained earlier, connecting the series circuit of the second inductor L2 and the second capacitor C2 in parallel with the first inductor L1 can also achieve the same effect.

[0105] As explained above, the power supply device of Embodiment 1 includes a capacitive load and an AC power supply as a voltage source for applying AC voltage to the capacitive load. The power supply device has the following structure: a series circuit of a first inductor and a first capacitor is connected to the AC power supply; a series circuit of a load inductor and a capacitive load is connected in parallel to either the first inductor or the first capacitor; the resonant frequency of the first inductor and the first capacitor coincides with the resonant frequency of the load inductor and the capacitive load; and the frequency of the AC power supply coincides with the resonant frequency. Therefore, with respect to the power supply device of Embodiment 1, the Q value of the resonant circuit can be freely designed, the step-up ratio can be increased, and a high voltage for driving the capacitive load can be generated without using a transformer.

[0106] Implementation method 2.

[0107] In the power supply device of Embodiment 2, an AC voltage source drives an inductive load.

[0108] The structural diagram of a power supply device that uses an AC voltage source and a series resonant circuit to drive an inductive load is as follows: Figure 6 The power supply device of Embodiment 2 will be described with a focus on the differences from Embodiment 1.

[0109] In Implementation Method 2 Figure 6 In this document, the same reference numerals are added to the parts that are the same as or equivalent to those in Embodiment 1.

[0110] In addition, to distinguish it from Embodiment 1, it is designated as a power supply device 200.

[0111] In Embodiment 1, the driving of capacitive loads such as ozone generators and lamps using barrier discharge is described.

[0112] In Embodiment 2, the case where the basic structure of the power supply device 100 of Embodiment 1 can also be used to drive an inductive load will be described.

[0113] Here, an inductive load refers to a load whose electrical characteristics include a strong inductive component, such as the induction heating coil of an IH (induction heating) cooking heater, which is a representative example.

[0114] The power supply device 200 includes an AC power supply 1 as an AC voltage source, an inductive load 8, a load capacitor 11 that forms a resonant circuit with the inductive load 8, an inductor 6 and a capacitor 7 used to amplify the Q value of the resonant circuit.

[0115] The inductive load 8 is the load that the AC power supply 1 is to drive. The equivalent circuit of the inductive load 8 is represented by the equivalent inductor 9 as the inductive component and the equivalent resistor 10 as the resistive component.

[0116] exist Figure 6 In this embodiment, the equivalent circuit of the inductive load 8 is represented by the series connection of the equivalent inductor 9 and the equivalent resistor 10. However, as explained in Embodiment 1, depending on the inductive load, it is sometimes more appropriate to represent it by the parallel connection of the equivalent inductor and the equivalent resistor, or by the equivalent resistor connected in series with the equivalent inductor and the equivalent resistor connected in parallel with the equivalent inductor.

[0117] Although the circuitry is slightly different, the processing methods are not significantly different, therefore it is set as follows: Figure 6 The inductive load 8 is represented by the series connection of the equivalent inductor 9 and the equivalent resistance 10.

[0118] Here, let the inductance of the equivalent inductor 9 be Ls, and the electrostatic capacitance of the load capacitor be Cs.

[0119] according to Figure 6 It can be seen that the AC power supply 1, capacitor 7 (electrostatic capacitance is Cp), and inductor 6 (inductance is Lp) serving as voltage sources are consistent with those in Embodiment 1. Figure 1 They are common. The series circuit of load capacitor 11 (with electrostatic capacitance of Cs) and inductive load 8 is connected in parallel to capacitor 7.

[0120] This can be clearly seen by expressing it using an equivalent circuit. Figure 6 The circuit and implementation method 1 Figure 1 They are exactly the same, and the same effect can be expected.

[0121] When the frequency of AC power supply 1 is fv, if the circuit constants, namely the equivalent inductance Ls of equivalent inductor 9, the electrostatic capacitance Cs of load capacitor 11, the inductance Lp of inductor 6, and the electrostatic capacitance Cp of capacitor 7, are determined in a manner that satisfies equation (1), then a high voltage can be applied to the two ends of inductive load 8.

[0122] In other words, by connecting the series circuit of inductor 6 and capacitor 7 to AC power supply 1, and connecting the series circuit of load capacitor 11 and inductive load 8 in parallel to either inductor 6 or capacitor 7, the resonant frequency of inductor 6 and capacitor 7 is made to match the resonant frequency of load capacitor 11 and inductive load 8, and the frequency fv of AC power supply is made to match the resonant frequency, thus enabling a high voltage to be applied across the inductive load 8.

[0123] Although not illustrated, the same result can be achieved as described above. Figure 6 Implementation method 1 Figures 2-4 The structure shown in the figure.

[0124] In other words, by adding a series resonant circuit of capacitor 7 and inductor 6, and using an AC voltage source, a higher voltage can be applied to the inductive load 8 than that achievable with the usual series resonance of inductive load 8 and load capacitor 11.

[0125] Implementation method 3.

[0126] In the power supply device of Embodiment 3, an AC current source drives an inductive load.

[0127] The structural diagram of a power supply device that uses an alternating current source and a parallel resonant circuit to drive an inductive load is as follows: Figures 7-9 The structural diagram of a power supply device driving two inductive loads is as follows: Figure 10 And a structural diagram of a power supply device that uses an alternating current source and a parallel resonant circuit to drive a capacitive load. Figure 11 The power supply device of Embodiment 3 will be described with a focus on the differences from Embodiment 1.

[0128] In implementation method 3 Figures 7-11 In this document, the same reference numerals are added to the parts that are the same as or equivalent to those in Embodiment 1.

[0129] In addition, to distinguish it from Embodiment 1, it is provided as a power supply device 300.

[0130] In Embodiment 2, an example is described in which an AC power source is used as a voltage source for the purpose of applying a voltage higher than that of a normal series resonance to an inductive load.

[0131] However, inductive loads are generally inductors, or coils, and are therefore mostly used to allow large currents to flow rather than to apply high voltages. Moreover, parallel resonant circuits are more suitable than series resonant circuits for "amplifying" large currents rather than "boosting" high voltages.

[0132] In parallel resonance, an inductor and a capacitor are connected in parallel to an AC current source. Even if the current from the AC power source is very small, the current in the inductor and capacitor is greatly amplified through resonance. Therefore, a large current can flow through the inductor or capacitor.

[0133] based on Figure 7 The basic structure of the power supply device 300 in Embodiment 3 is explained. Additionally, refer to [reference needed] as appropriate. Figure 8 , Figure 9 To illustrate the basic structure of the power supply device 300, i.e. Figure 7 A variation of the above.

[0134] The power supply device 300 includes an AC power supply 12 as an AC current source, an inductive load 8, a load capacitor 11 that forms a resonant circuit with the inductive load 8, an inductor 6 and a capacitor 7 used to amplify the Q value of the resonant circuit.

[0135] Although Figure 7 In the diagram, the inductive load 8 is represented by a series circuit of the equivalent inductor 9 and the equivalent resistance 10, but sometimes it is also represented as... Figure 8 It would be more appropriate to represent it by a parallel circuit of equivalent inductor 9 and equivalent resistor 10.

[0136] In addition Figure 8 In order to cooperate with Figure 7 The power supply device 300 is phase-separated and is designated as power supply device 301.

[0137] Here, let the inductance of the equivalent inductor 9 be Ls, and the resistance of the equivalent resistance 10 be RL. The equivalent inductance Ls and equivalent resistance RL are determined by the physical operation of the inductive load 8 and generally vary over time. However, their average values ​​can be used when processing the circuit.

[0138] Similar to implementation 1, the equivalent inductance Ls or equivalent resistance value RL defined here is such an equivalent average value.

[0139] When driving the inductive load 8 in a parallel resonant manner, a capacitor is connected in parallel. Figure 7 The load capacitor 11 is a capacitor used for parallel resonance. Here, let the electrostatic capacitance of the load capacitor 11 be Cs.

[0140] In this application, in addition to the above, capacitor 7 and inductor 6 are as follows Figure 7 They are connected in parallel to AC power supply 12. Here, the capacitance of capacitor 7 is Cp, and the inductance of inductor 6 is Lp.

[0141] In the sense of load as observed from AC power supply 12, the circuit including the inductive load 8 and including capacitor 7 (static capacitance Cp), inductor 6 (inductance Lp) and load capacitor 11 (static capacitance Cs) constituting the resonant circuit of this application is described as load circuit 321.

[0142] Furthermore, in implementation method 3, in Figure 8 The circuit diagram corresponding to load circuit 321 is omitted from hereafter.

[0143] The operating characteristic of the load circuit 321 is that the resonant circuit has two stages.

[0144] That is, the first-stage resonant circuit is formed by the capacitor 7 and the inductor 6 connected in parallel to the AC power supply 12. The second-stage resonant circuit is formed by the parallel circuit of the inductive load 8 connected in series to the inductor 6 and the load capacitor 11.

[0145] When the resonant frequencies of the first-stage resonant circuit and the second-stage resonant circuit are both consistent with the frequency fv of the AC power supply 12 and equation (1) holds, a large current can flow through the inductive load 8 in the same way as the principle described in embodiment 1.

[0146] That is, by making the current flowing out of the AC power supply 12, which is the source of AC current, resonate first in the resonant circuit of the inductor 6 and capacitor 7 in the first stage, and then resonate in the resonant circuit of the load capacitor 11 and inductive load 8 in the second stage, a large current can be made to flow through the inductive load 8.

[0147] The load circuit 321 is characterized by its ability to freely design the current amplification rate. Since the description of this feature is the same as in Embodiment 1, it will be omitted.

[0148] Because Figure 7 In the circuit, the inductor 6 and capacitor 7 in the first stage play an equivalent role under resonant conditions, so they can also be interchanged to form a circuit like this. Figure 9 That kind of structure.

[0149] In addition Figure 9 In order to cooperate with Figure 7 The power supply device 300 is distinguished and designated as power supply device 302.

[0150] By connecting the parallel circuit of inductor 6 and capacitor 7 to AC power supply 12, and connecting the parallel circuit of load capacitor 11 and inductive load 8 in series to either inductor 6 or capacitor 7, the resonant frequency of inductor 6 and capacitor 7 is made to match the resonant frequency of load capacitor 11 and inductive load 8, and the frequency fv of AC power supply 12 is made to match the resonant frequency. This allows for free design of the Q value of the resonant circuit, improving the current amplification rate, and generating high current to drive the inductive load without the need for a transformer.

[0151] Next, based on Figure 10 This illustrates the scenario where two inductive loads are driven simultaneously by a single AC power supply. (Hereinafter, in...) Figure 10 In order to cooperate with Figure 7 The power supply device 300 is phase-separated and is designated as power supply device 303.

[0152] The power supply device 303 includes: an AC power supply 12, two inductive loads 8a and 8b, load capacitors 11a and 11b that form a resonant circuit with each inductive load 8a and 8b, and an inductor 6 and a capacitor 7 used to amplify the Q value of the resonant circuit.

[0153] Inductive load 8a has an equivalent inductor 9a and an equivalent resistance 10a. Inductive load 8b has an equivalent inductor 9b and an equivalent resistance 10b.

[0154] Here, the inductive load 8b and the load capacitor 11 are the first inductive load and the second load capacitor as claimed.

[0155] Figure 10 The circuit is characterized by being able to drive two inductive loads 8a and 8b simultaneously using a single AC power supply 12. The inductive loads 8a and 8b can be the same or different. However, it is necessary to maintain the resonance condition, i.e., equation (1), in each resonant circuit.

[0156] Parallel resonant circuits can also be used to drive the capacitive load described in Implementation 1. Figure 11 The diagram shows a structural example of a power supply device that uses a parallel resonant circuit to drive a capacitive load.

[0157] Here Figure 11 In order to cooperate with Figure 7 The power supply device 300 is phase-separated and is designated as power supply device 304.

[0158] In the power supply device 304, the inductor 6 and the capacitor 7 form a first-stage parallel resonant circuit, and the capacitive load 2 and the load inductor 5 form a second-stage parallel resonant circuit.

[0159] That is, in the power supply device 304, the capacitive load 2 is driven by the AC power supply 12, which serves as the AC current source, through a parallel resonant circuit formed by using the inductor 6 and the capacitor 7.

[0160] In other words, by adopting the following structure: connecting the parallel circuit of inductor 6 and capacitor 7 to AC power supply 12, and connecting the parallel circuit of load inductor 5 and capacitive load 2 in series to either inductor 6 or capacitor 7, the resonant frequency of inductor 6 and capacitor 7 is made to match the resonant frequency of load inductor 5 and capacitive load 2, and the frequency of AC power supply is made to match the resonant frequency. Thus, the Q value of the resonant circuit can be freely designed using an AC current source, improving the current amplification rate, and generating a high current to drive the capacitive load without the need for a transformer.

[0161] Furthermore, based on Figure 11 The power supply unit 304 can also be connected with Figure 10 The power supply unit 303 is also configured to simultaneously drive two capacitive loads.

[0162] As explained above, in the power supply device of Embodiment 3, an AC current source drives an inductive load.

[0163] Therefore, regarding the power supply device of Embodiment 3, the Q value of the resonant circuit can be freely designed using an AC power supply as a current source, improving the current amplification rate and generating a high current to drive the inductive load without using a transformer.

[0164] Implementation method 4.

[0165] In Embodiment 4, specific structural examples will be described for the AC voltage source described in Embodiment 1 and the AC current source described in Embodiment 3.

[0166] The structural diagram of a power supply device based on an AC voltage source using IGBTs is as follows: Figure 12 The structural diagram of a power supply device that uses MOSFETs to construct an AC voltage source is as follows: Figure 13 The structural diagram of a power supply device that uses thyristors to form an alternating current source is as follows: Figure 14 And the structural diagram of a power supply device that uses IGBTs to form an AC current source. Figure 15 The power supply device of Embodiment 4 will be described.

[0167] In the structural diagram of Embodiment 4, the same reference numerals are added to the parts that are the same as or equivalent to those in Embodiments 1 and 3.

[0168] First, let's explain the AC voltage source.

[0169] A voltage source is a power supply designed to control the output voltage to a certain value. Ideally, the output voltage should not change no matter how much the current increases, meaning the internal impedance of the power supply is zero.

[0170] Although a power source with zero internal impedance does not actually exist, this characteristic is taken into account when designing power supplies. An AC voltage source is a voltage source whose voltage value varies at a certain frequency.

[0171] based on Figure 12 The power supply device 400, which uses IGBTs to form an AC voltage source, is described.

[0172] The power supply unit 400 includes an AC voltage source 1A, a control circuit 13 that controls the inverter section of the AC voltage source 1A, and a load circuit 21.

[0173] The AC voltage source 1A includes a constant voltage source 14, a capacitor 15 for stabilizing the output voltage of the constant voltage source 14, and a full-bridge inverter 30 composed of four IGBTs as components.

[0174] Here, AC voltage source 1A corresponds to embodiment 1. Figure 1 AC power supply 1.

[0175] Control circuit 13 controls the switching of the IGBT to obtain an AC waveform of a predetermined frequency. The IGBT is a voltage-type device, and the voltage waveform output from the full-bridge inverter 30 is determined by the constant voltage source 14 and the switching waveform. That is, the AC voltage source 1A functions as a voltage-type inverter.

[0176] The load circuit 21 includes a capacitive load 2 consisting of an equivalent capacitor 3 and an equivalent resistor 4, a load inductor 5, a capacitor 7, and an inductor 6. The load circuit 21 has already been described in Embodiment 1, so the description is omitted here.

[0177] Next based on Figure 13 The power supply device 401, which uses MOSFETs to construct an AC voltage source, will be described. Furthermore, in... Figure 13 In order to cooperate with Figure 12 The power supply device 400 is phase-separated and is designated as power supply device 401.

[0178] The power supply unit 401 includes an AC voltage source 1B, a control circuit 13 that controls the inverter section of the AC voltage source 1B, and a load circuit 21.

[0179] The AC voltage source 1B includes a constant voltage source 14, a capacitor 15 for stabilizing the output voltage of the constant voltage source 14, and a half-bridge inverter 31 consisting of two MOSFETs as components.

[0180] Here, AC voltage source 1B corresponds to embodiment 1. Figure 1 AC power supply 1.

[0181] Control circuit 13 controls the switching of the MOSFET to obtain an AC waveform of a predetermined frequency. The MOSFET is a voltage-type device, and the voltage waveform output from the half-bridge inverter 31 is determined by the constant voltage source 14 and the switching waveform. That is, the AC voltage source 1B functions as a voltage-type inverter.

[0182] The AC current source will be explained next.

[0183] A current source is a power supply designed to control the output current value to a certain value. Ideally, it should be able to maintain a constant current value no matter how high the output voltage becomes, that is, a power supply with zero internal admittance (infinite impedance).

[0184] A power supply with infinite impedance is practically impossible to implement, but this characteristic is taken into account when designing power supplies. An alternating current source is a current source whose current value varies at a certain frequency.

[0185] based on Figure 14 The power supply device 402, which uses thyristors to form an alternating current source, will be described. Furthermore, Figure 14 In order to cooperate with Figure 12 The power supply device 400 is phase-separated and designated as power supply device 402.

[0186] The power supply unit 402 includes an AC current source 12A, a control circuit 13 that controls the inverter section of the AC current source 12A, and a load circuit 321.

[0187] The AC current source 12A includes a constant current source 16, an inductor 17 for stabilizing the output current of the constant current source 16, and a full-bridge inverter 32 consisting of four thyristors as components.

[0188] Here, the AC current source 12A corresponds to Embodiment 3. Figure 7 AC power supply 12.

[0189] Control circuit 13 controls the switching of the thyristors to obtain an AC waveform of a predetermined frequency. The thyristors are current-source devices; by switching the current on and off (ON / OFF), the full-bridge inverter 32 outputs a current waveform determined by the constant current source 16 and the switching waveform. That is, the AC current source 12A functions as a current-source inverter.

[0190] The load circuit 321 includes an inductive load 8 consisting of an equivalent inductor 9 and an equivalent resistor 10, a load capacitor 11, a capacitor 7, and an inductor 6. The load circuit 321 has already been described in Embodiment 3, so the description is omitted here.

[0191] Current-source inverters are typically constructed using thyristors as current switching elements. In addition to conventional thyristors, GTOs (Gate Turn Off thyristors), GCTs (Gate Commutated Turn Off thyristors), SI thyristors (Static Induction thyristors), and MOS gate thyristors can also be used.

[0192] Recently, due to the prevalence of voltage-source switching devices such as IGBTs and MOSFETs, inverters have also increasingly adopted voltage-source technology. However, current-source power supplies are suitable when using parallel resonant circuits, and when using voltage-source switching devices, the characteristics of the voltage-source inverter should be made to approximate those of the current-source inverter.

[0193] Figure 15 The structure example for this situation is shown in the diagram. Furthermore, in... Figure 15 In order to cooperate with Figure 12 The power supply device 400 is phase-separated and designated as power supply device 403.

[0194] The power supply unit 403 includes an AC current source 12B, a control circuit 13 that controls the inverter section of the AC current source 12B, and a load circuit 321.

[0195] The AC current source 12B includes a constant voltage source 14, a capacitor 15 for stabilizing the output voltage of the constant voltage source 14, a full-bridge inverter 30 composed of four IGBTs as components, and an inductor 18 for stabilizing the output current of the full-bridge inverter 30.

[0196] Here, inductor 18 has a high inductance value. By setting this inductor 18, the output current of the full-bridge inverter 30 is stabilized, the power supply impedance observed from the secondary side of inductor 18 becomes higher, and the inverter circuit, including inductor 18, has characteristics close to those of an AC current source.

[0197] Furthermore, the description of control circuit 13 is the same as that in power supply device 400, and the description of load circuit 321 is the same as that in power supply device 402, so the description is omitted.

[0198] A real power source is not an ideal voltage source or an ideal current source; its internal impedance is a finite value that is neither zero nor infinite. Ultimately, it is a power source designed with voltage or current as its goal, or one whose characteristics are close to those of voltage or current sources.

[0199] In this application, "AC voltage source" means a power source designed with the goal of being a voltage source and whose characteristics are similar to those of a voltage source. Similarly, "AC current source" means a power source designed with the goal of being a current source and whose characteristics are similar to those of a current source.

[0200] The above explanation only used an inverter employing switching elements as an example, but there are other methods to obtain AC voltage. For example, a bipolar power supply based on a linear amplifier can be used. Furthermore, commercial frequencies or harmonics can be used directly when frequency variation is not required.

[0201] Implementation method 5.

[0202] In the power supply device of Embodiment 5, a mechanism is provided for adjusting the inductance of the inductor constituting the resonant circuit or the electrostatic capacitance of the capacitor.

[0203] The structural diagram of the power supply device with an inductor adjustment circuit is as follows: Figure 16 And a structural diagram of a power supply device equipped with an electrostatic capacitor regulation circuit. Figure 17 The power supply device of Embodiment 5 will be described with a focus on the differences from Embodiment 1.

[0204] In the structural diagram of Embodiment 5, the same reference numerals are added to the parts that are the same as or equivalent to those in Embodiment 1.

[0205] As described in Embodiment 1, the Q value of the resonant circuit can be freely designed by using the structure of the power supply device of this application. In other words, the Q value can also be set to a very high value.

[0206] However, when the Q value is high, the frequency range of resonance becomes narrower. In other words, when fabricating a circuit with a high Q value, it is difficult to achieve resonant circuit matching.

[0207] A resonant circuit consists of an inductor and a capacitor, and the characteristics of these components typically change with temperature and time. That is, the inductance and capacitance change.

[0208] In addition, regarding capacitive or inductive loads, their electrical characteristics generally change when operating conditions change.

[0209] Regarding barrier discharge loads as capacitive loads, it is generally known that the average capacitance varies with changes in power. Changes in the inductance or capacitance of such circuits affect the resonant characteristics of the circuit. It is also generally believed that in cases where the Q value is very high and the resonant frequency range is extremely narrow, the circuit will deviate from resonance and cease to function.

[0210] Therefore, it is preferable that when using the power supply device of this application, there are some adjustment mechanisms to maintain circuit resonance.

[0211] In implementing an adjustment mechanism to maintain circuit resonance, there are two technical challenges: the means of adjusting resonance and the control method based on and how to perform the adjustment. These will be explained in turn.

[0212] First, the methods for adjusting resonance will be explained.

[0213] The easiest way to adjust resonance is through frequency modulation.

[0214] In the power supply device of this application, Embodiment 4 mainly describes the case where an inverter is used as the AC power source. The embodiment 4... Figures 12-15 The control circuit 13 for controlling each inverter, as described in power supply units 400 to 403, can easily make its frequency variable.

[0215] Therefore, it is preferable to have a mechanism for controlling the frequency in the inverter of the power supply device used in this application.

[0216] On the other hand, the case where the frequency is immutable is also taken into consideration.

[0217] For example, situations that require operation at a specific frequency, situations where a frequency command value is given from an external source, or situations that require compatibility with other devices.

[0218] Additionally, this is equivalent to using a fixed-frequency AC power source instead of an inverter, such as directly using AC power from the grid, or wanting to oscillate at 13.56MHz or its multiples due to restrictions imposed by radio laws.

[0219] In this case, a fixed frequency and adjusted circuit constants are required to achieve resonance matching. For this purpose, a mechanism is provided that can adjust the inductance of the inductor or the electrostatic capacitance of the capacitor.

[0220] Figure 16 The diagram shows a specific example of the structure of a power supply device that uses this regulating mechanism.

[0221] The power supply unit 500 includes an AC power supply 1 as a voltage source, a capacitive load 2 consisting of an equivalent capacitor 3 and an equivalent resistor 4, a variable load inductor 5A that forms a resonant circuit with the capacitive load 2, and a capacitor 7 and an inductor 6 used to amplify the Q value of the resonant circuit.

[0222] The power supply unit 500 also includes: a voltage detector 19 for detecting the voltage applied to the capacitive load 2; and an adjustment mechanism 40 for adjusting the inductance of the variable load inductor 5A.

[0223] When adjusting the inductance of an inductor (coil), mechanical adjustment is usually required. The adjustment mechanism 40 described herein includes such a mechanical adjustment mechanism.

[0224] Furthermore, a voltage detector 19 can be provided to detect the voltage of the circuit, and the detected voltage value can be fed back to the adjustment mechanism 40. In this case, the adjustment mechanism 40 adjusts the inductance value of the variable load inductor 5A in a manner that maximizes the detected voltage.

[0225] Figure 16 The power supply unit 500 employs a structure that uses an adjustment mechanism 40 to feedback adjust the inductance value of the variable load inductor 5A based on the voltage value from the voltage detector 19.

[0226] In addition, although Figure 16 The power supply device 500 is for embodiment 1. Figure 1 The power supply device 100 has a load inductor 5 equipped with an adjustment mechanism, but it can also be used in embodiment 3. Figure 7 The load capacitor 11 of the power supply device 300 is equipped with an adjustment mechanism.

[0227] Figure 17 The diagram shows the implementation method 3. Figure 7 An example of a structure in which the load capacitor 11 of the power supply device 300 is equipped with an adjustment mechanism. Furthermore, in... Figure 17 In order to cooperate with Figure 16The power supply device 500 is distinguished and designated as power supply device 501.

[0228] Figure 17 The power supply unit 501 uses the adjustment mechanism 41 to adjust the electrostatic capacitance value of the variable load capacitor 11A based on the voltage value from the voltage detector 19.

[0229] Furthermore, an adjustment mechanism can be provided for the inductor 6 or capacitor 7 that constitute the first stage resonant circuit of the power supply device 100 or the power supply device 300.

[0230] That is, for example, regarding implementation method 1 Figure 1 The power supply device 100 is equipped with an effective adjustment mechanism that allows at least one of the inductance or electrostatic capacitance of the inductor 6, the capacitor 7, and the load inductor 5 to be variable.

[0231] Additionally, for example, regarding implementation method 3 Figure 7 The power supply device 300 is equipped with an adjustment mechanism that makes at least one of the inductance or electrostatic capacitance of the inductor 6, the electrostatic capacitance of the capacitor 7, and the electrostatic capacitance of the load capacitor 11 variable.

[0232] Furthermore, the adjustment mechanisms described in Embodiment 5 can be installed in Embodiment 2. Figure 6 The power supply device 200 and embodiment 3 Figure 11 Power supply device 304.

[0233] Furthermore, it also considers situations where the frequency of the AC power supply can be varied, but the range of variation is limited.

[0234] For example, in barrier discharge in ozone generators, the appropriate frequency range is limited because the switching power is proportional to the frequency. Furthermore, the variation in the circuit constants of circuit elements, or the large variation in the average electrostatic capacitance of capacitive loads due to operating conditions, sometimes makes adjustment within a variable frequency range possible using a power supply. In such cases, providing a mechanism to adjust the circuit constants of circuit elements is a solution.

[0235] In this case, since the inverter can be used to fine-tune the frequency within a narrow frequency range, it is not necessary to continuously change the value of the inductor or capacitor; it is sufficient to adjust it in several levels.

[0236] Specifically, by connecting multiple inductors or capacitors in parallel and switching them with relays, the values ​​of the inductors or capacitors can be adjusted.

[0237] Implementation method 6.

[0238] In Implementation 6, the permissible range of variation of the circuit constants of the resonant circuit constituting the power supply device and the frequency of the AC power supply is quantitatively studied.

[0239] In order for the power supply device of this application to fully perform, it is necessary to satisfy equation (1). However, for example, when the average electrostatic capacitance Cs of the capacitive load changes, changing the frequency alone cannot make both of the two equality signs in equation (1) hold true. Although it is possible to make both equality signs in equation (1) hold true simultaneously by setting up two mechanisms to change the inductance or electrostatic capacitance, physically changing the circuit constant would complicate the mechanical construction.

[0240] Therefore, in the design of the power supply device of this application, firstly, even if the design is to satisfy equation (1) under rated conditions, it is necessary to confirm the range of variation of the load's electrostatic capacitance or inductance. Furthermore, when the load's electrostatic capacitance or inductance varies, especially when the circuit constant changes according to the load's power and other operating conditions, it is necessary to confirm how the circuit constant changes during these changes, as well as during transient responses and startup. Furthermore, it is also necessary to confirm the extent to which the change in the circuit constant affects resonance and whether there are any problems with the circuit's operation.

[0241] In this case, the frequency of the inverter can be controlled to ensure proper resonance matching. The key point of the power supply device in this application is to construct a circuit that satisfies equation (1). If the circuit's inductance and capacitance change simultaneously, violating the conditions of equation (1) and the resonance is no longer perfectly matched, countermeasures need to be taken.

[0242] That is, the key is how to change the frequency, how to design the allowable range of operation, and the control methods.

[0243] Next, regarding the power supply device of this application, a quantitative study will be conducted on the extent to which the equality of equation (1) can be deviated.

[0244] When the load voltage is boosted to Vp at the resonant angular frequency ω0 (resonant point), the angular frequency of the load voltage will be changed from ω0 to a slightly lower direction, and the angular frequency at which the load voltage changes to Vp / 2 will be set as ω1. Similarly, the angular frequency at which the load voltage changes to a slightly higher direction and changes to Vp / 2 will be set as ω2.

[0245] The value of Q is then expressed by equation (4). Furthermore, equation (5) is derived from equation (4).

[0246] Q=ω0 / (ω2-ω1) (4)

[0247] ω2-ω1=ω0 / Q (5)

[0248] Here, assuming that the desired Q value of the power supply device of this application is 5 or more, preferably 10 or more, when Q = 5, the frequency width at which the voltage changes to half is 20% of the resonant frequency, and when Q = 10, the frequency width at which the voltage changes to half is 10% or less.

[0249] When considering this in equation (1), when assuming Q = 5, the right side of equation (1) changes by ±20% over a 20% range relative to the resonant frequency, i.e., ±10%. Similarly, when assuming Q = 10, the right side of equation (1) changes by ±10% over a 10% range relative to the resonant frequency, i.e., ±5%.

[0250] This applies not only to frequency, but also to circuit constants.

[0251] In other words, when Q=5, for example, if the circuit constant changes, the result is that when Lp×Cp changes by 20%, it means that when driven at the original frequency fv before the change, the boost voltage becomes half.

[0252] This view serves as the benchmark for the range of variation in equation (1). That is, when Q = 5, a design should be made assuming that each item in equation (1) varies by approximately ±20%.

[0253] As the Q value increases, the (allowed) range of variation also decreases; for example, if Q = 10, it is approximately ±10%.

[0254] When the above research results are expressed by expressions, the allowable range of variation of each circuit constant when Q=5 is given by equations (6) and (7).

[0255] 0.8 / ((2π·fv)^2)<Lp·Cp<1.2 / ((2π·fv)^2) (6)

[0256] 0.8 / ((2π·fv)^2)<Ls·Cs<1.2 / ((2π·fv)^2) (7)

[0257] When Q = 10, the allowable range of variation for each circuit constant is given by equations (8) and (9).

[0258] 0.9 / ((2π·fv)^2)<Lp·Cp<1.1 / ((2π·fv)^2) (8)

[0259] 0.9 / ((2π·fv)^2)<Ls·Cs<1.1 / ((2π·fv)^2) (9)

[0260] Therefore, as explained previously, since the Q value of the power supply device in this application is targeted to be 5 or higher, for example, for Embodiment 1... Figure 1The power supply device 100 is effective when it adopts a structure that basically satisfies equations (6) and (7).

[0261] In addition, regarding implementation method 2 Figure 6 The power supply device 200, which adopts a structure that basically satisfies equations (6) and (7), is effective.

[0262] In addition, regarding implementation method 3 Figure 7 Power supply device 300 and Figure 11 The power supply device 304 is effective when it adopts a structure that basically satisfies equations (6) and (7).

[0263] Implementation method 7.

[0264] Embodiment 7 relates to a power supply device with the following structure: wherein either or both of the voltage and current of the resonant circuit are detected and fed back to the control circuit of the inverter to maintain the resonant state; and to a power supply device with the following structure: wherein the resonant state is maintained by detecting the voltage and current of the AC power supply and minimizing the phase difference between the voltage and current.

[0265] The structural diagram of a power supply device controlled according to the voltage of a capacitive load is as follows: Figure 18 A structural diagram of a power supply device that controls the current of a capacitive load. Figure 19 A structural diagram of a power supply device that controls the current of an AC power source. Figure 20 And a structural diagram of a power supply device that controls the voltage and current of an AC power source. Figure 21 The power supply device of Embodiment 7 will be described with a focus on the differences from Embodiment 1.

[0266] In the structural diagram of Embodiment 7, the same reference numerals are added to the parts that are the same as or equivalent to those in Embodiment 1.

[0267] In Implementation Method 7, a control method for confirming and controlling the resonance of the resonant circuit is explained. Furthermore, specific examples of the structure of a power supply device to which each control method is applied are described.

[0268] Although the application of each control method is based on implementation method 1 Figure 1 The power supply device 100 can also be applied to other power supply devices.

[0269] First, based on Figure 18 This section describes an example of the structure of a power supply device that controls the voltage of a capacitive load. Figure 18 In order to be consistent with implementation method 1 Figure 1 The components are distinguished as power supply device 701 and control circuit 13A.

[0270] The power supply device 701 includes an AC power supply 1 as a voltage source, a capacitive load 2 consisting of an equivalent capacitor 3 and an equivalent resistor 4, a load inductor 5 that forms a resonant circuit with the capacitive load 2, and a capacitor 7 and an inductor 6 used to amplify the Q value of the resonant circuit.

[0271] The power supply unit 701 also includes: a voltage detector 19 for detecting the voltage applied to the capacitive load 2; and a control circuit 13A for controlling the inverter section of the AC power supply 1, which serves as an AC voltage source, based on the voltage detected by the voltage detector 19.

[0272] Furthermore, in the power supply device 701 of Embodiment 7, since the capacitive load 2, load inductor 5, capacitor 7 and inductor 6 are the same as those in the power supply device 100 of Embodiment 1, only the additional control circuit 13A and voltage detector 19 will be described.

[0273] The voltage detector 19, which detects the voltage across the capacitive load 2, detects the voltage applied to the capacitive load 2, i.e., the voltage across the voltage detector 19, and feeds it back to the control circuit 13A to control the inverter section of the AC power supply 1, which serves as an AC voltage source.

[0274] Specifically, since the voltage across the capacitive load 2 is AC, the amplitude of the detected voltage by the voltage detector 19 is fed back to the control circuit 13A to control the frequency of the inverter so that the amplitude of the detected voltage is maximized.

[0275] For power supply devices that aim to boost voltage using a series resonant circuit, this is the most direct method of detection and control.

[0276] Next, based on Figure 19 This section describes an example of the structure of a power supply device that controls the current based on the capacitive load. Figure 19 In order to cooperate with Figure 18 The components are distinguished as power supply device 702 and control circuit 13B.

[0277] Figure 19 Power supply unit 702 and Figure 18 The difference in the power supply device 701 is that the current flowing through the capacitive load 2 is detected by the current detector 20, instead of the voltage across the capacitive load 2 being detected by the voltage detector 19. This point will be explained only.

[0278] Since the current usually increases when the voltage rises, the current flowing through the capacitive load 2 is detected by the current detector 20 and fed back to the control circuit 13B to maximize the detected current, thereby indirectly searching for the resonant point.

[0279] Figure 19 This is an example of applying current sensing to a voltage resonant circuit.

[0280] Although not illustrated, the detection is as described in Implementation Method 3. Figure 7 The current of the inductive load 8 in the current resonant circuit of the power supply device 300, and... Figure 18 Similarly, the voltage detection method is a direct method for detecting the current that needs to be amplified as a control target. By feeding the detected current back to the control circuit, the detection current is maximized, thereby enabling direct searching of the resonant point.

[0281] In addition, regarding implementation method 3 Figure 7 The power supply device 300 detects the voltage of the inductive load 8 and feeds the detected voltage back to the control circuit for control so that the detected voltage is maximized, thereby indirectly searching for the resonant point.

[0282] exist Figure 18 In the power supply device 701, it is also possible to detect the voltage of the capacitor 7 instead of detecting the voltage across the capacitive load 2. However, in this case, detecting the resonant state of the first stage is an indirect detection method.

[0283] In addition, when it comes to the detection of voltage or current, observing its amplitude or effective value is the easiest and most definitive detection method, but it is also possible to consider observing the harmonics of the waveform.

[0284] In other words, this is because the closer the resonant circuit is to resonance, the closer its voltage and current waveforms are to a sine wave, and the smaller the proportion of harmonics. By monitoring the harmonics of the voltage and current waveforms of the resonant circuit and controlling them to make the voltage and current waveforms as close to a sine wave as possible, the harmonics can be minimized, thereby allowing the circuit to approach the resonance point.

[0285] Next, based on Figure 20 An example of the structure of a power supply device that controls the current of an AC power source will be described. Figure 20 In order to cooperate with Figure 18 The components are distinguished as power supply device 703 and control circuit 13C.

[0286] Figure 20 Power supply unit 703 and Figure 19 The difference in the power supply device 702 is that the current flowing through the inductor 6 is detected by the current detector 20, instead of the current flowing through the capacitive load 2.

[0287] exist Figure 20 Although it detects the current flowing through inductor 6, it should more accurately be considered as detecting the current of the inverter of AC power supply 1. It's important to note that when the connected power of capacitive load 2 is the same, Figure 20 The smaller the detection current, the closer it is to the resonance point.

[0288] Furthermore, it is preferable to control the inverter of AC power supply 1 in such a way that the power factor of the load, including the resonant circuit, observed from the inverter output is as close to 1 as possible when detecting the current of the inverter. That is, by detecting the output voltage and output current of AC power supply 1, control is performed to make the phases of the output voltage and output current as similar as possible, that is, to minimize the phase difference between the output voltage and output current, thereby approaching the resonant point.

[0289] Figure 21 The specific structural example of this situation is shown below. Figure 21 In order to cooperate with Figure 18 The components are distinguished as power supply device 704 and control circuit 13D.

[0290] exist Figure 21 In the power supply device 704, the output voltage and output current of the AC power supply 1 are detected, and the control circuit 13D controls the output voltage and output current based on the output voltage and output current to minimize the phase difference between the output voltage and output current.

[0291] In this case, it is a voltage-source inverter, and the control circuit 13D monitors the inverter output waveform. Therefore, it is preferable to perform the following control: make the current waveform as close to the voltage waveform of the inverter as possible to the same phase, i.e., the phase difference is zero, or as will be explained later, the current waveform is lagging, or switch the inverter at the instant the current is zero, i.e., perform so-called zero-voltage switching.

[0292] When the voltage and current waveforms of an inverter are in phase, it indicates that the power factor is at its maximum, meaning it is operating at the resonant point.

[0293] This control method can also be applied to current-source inverters, such as those described in Implementation Method 3. Figure 7 The power supply device 300.

[0294] That is, by controlling the AC power supply 12, which is an AC current source, to minimize the phase difference between the output voltage and the output current, it is possible to approach the resonant point (not shown).

[0295] The above describes a method for using voltage or current detectors to detect the state of a resonant circuit and control it to bring the circuit close to its resonant state. While the above description illustrates an example using only one voltage or current detector, it is also possible to use both, or multiple, voltage or current detectors to detect multiple voltages or currents.

[0296] In addition, a method for detecting the optimal drive conditions based on the phase difference between the inverter's voltage and current has been described. However, since the resonant state is sensitively manifested in the phase difference between the current and voltage, it is also useful to detect the voltage and current, detect the phase difference between the voltage waveform and the current waveform, and use it for control.

[0297] Furthermore, the method for maintaining the resonant state of the resonant circuit described in Embodiment 7 above can also be applied to Embodiment 2. Figure 6 The power supply device 200 and the power supply device 304 of Embodiment 3.

[0298] Implementation method 8.

[0299] Implementation 8 relates to a power supply device that achieves optimal operating conditions through feedforward control based on pre-saved optimal operating conditions.

[0300] The structural diagram of the power supply unit controlled based on pre-saved optimal operating conditions is as follows: Figure 22 The power supply device of Embodiment 8 will be described with a focus on the differences from Embodiment 1.

[0301] In the structural diagram of Embodiment 8, the same reference numerals are added to the parts that are the same as or equivalent to those in Embodiment 1.

[0302] In Implementation Method 7, a so-called closed-loop control, which detects current and voltage and feeds them back to the control system, was described. In contrast, open-loop, or feedforward, control can also be considered. For example, when the changes in load conditions for operating conditions are known in advance, the optimal frequency can be pre-determined based on the operating conditions.

[0303] For example, in an ozone generator, as described in Patent Document 1, the optimal frequency depends on the on-power. In such a case, a table of drive frequencies for a set power is pre-stored in memory, and the generator can be driven at the frequency corresponding to the power command value given externally.

[0304] Figure 22 The diagram shows a specific example of the structure of a power supply device using this feedforward control.

[0305] The power supply unit 800 includes an AC power supply 1 as a voltage source, a control circuit 13E for an inverter section that controls the AC power supply 1, a capacitive load 2 consisting of an equivalent capacitor 3 and an equivalent resistor 4, a load inductor 5 that forms a resonant circuit with the capacitive load 2, and a capacitor 7 and an inductor 6 used to amplify the Q value of the resonant circuit.

[0306] The power supply unit 800 also includes a storage unit 50, which stores a table of optimal frequencies for power command values. Furthermore... Figure 22 In this context, PI stands for power command.

[0307] The control circuit 13E receives a power command (PI) from an external source and, based on the command value of the power command, refers to a table stored in the storage unit 50 to set the frequency to the optimal frequency, thereby controlling the inverter of the AC power supply 1. Alternatively, the storage unit 50 may be located inside the control circuit 13E.

[0308] according to Figure 22 The power supply device 800 has the advantages of eliminating the need for voltage and current detection, and offering simple and high-speed control. Especially during startup when power fluctuates significantly, such as when the discharge transitions from an unlit state to an ignited state—a discontinuous change in characteristics—feedforward control is effective because control using a feedback system could be unstable. Furthermore, it is particularly effective in situations like the power supply device of this application, where the resonant circuit has a high Q value, a narrow operating frequency range, and where control using a feedback system could be unstable.

[0309] When the power supply unit 800 is started and the initial power setting is performed, feedforward control is performed based on a table of the optimal frequency for the power command value. In order to accurately maintain its state after it starts to operate stably, the voltage and current of the resonant circuit are detected and feedback control is performed. It is also effective to make flexible use of the advantages of both.

[0310] The above description explains the implementation method 1. Figure 1 An example of a power supply device 100 with an added control circuit 13E and a storage unit 50, and with feedforward control applied.

[0311] For implementation method 3 Figure 7 The same effect can be achieved by adding control circuitry and storage unit to the power supply unit 300 and applying feedforward control (not shown).

[0312] Furthermore, the method described in Embodiment 8 above can also be applied to Embodiment 2. Figure 6 The power supply device 200 and embodiment 3 Figure 11 Power supply device 304.

[0313] Implementation method 9.

[0314] In Embodiment 9, the resonant stability conditions of the resonant circuit constituting the power supply device will be explained.

[0315] In embodiments 5 to 8, methods for changing the circuit constant of the resonant circuit and the frequency of the AC power supply, as well as methods for detecting the voltage and current of the resonant circuit and providing feedback, are described. A method for feedforward control based on pre-saved optimal operating conditions is also described.

[0316] The above control methods all aim to maintain optimal conditions for resonance.

[0317] Here, the optimal conditions for resonance of a resonant circuit are explained.

[0318] As also stated in Patent Document 1, for ozone generators, the load circuit including the resonant circuit observed from the inverter is not exactly at the resonant point, but rather at the lagging phase, and the ozone generator, as a capacitive load, operates more stably.

[0319] Phase lag refers to the current phase lagging behind the voltage phase. In a simple LC series circuit, the impedances of the inductor (L) and capacitor (C) do not completely cancel each other out, but rather the inductance component is slightly excessive, i.e., it operates at a frequency slightly higher than the resonant frequency.

[0320] For blocking discharge loads such as ozone generators, this can be explained from the perspective of discharge stability. More generally, when driven by a voltage-source inverter, the inverter operates more stably if there is a slight phase lag.

[0321] Zero-voltage switching (ZVS), which involves switching the inverter at the instant the current waveform, which is approximately sinusoidal due to resonance, crosses zero, is considered to minimize losses. Furthermore, it is believed that adjusting the inverter in a direction that increases the frequency and delays the phase is more preferable than adjusting the frequency below ZVS (which leads the phase).

[0322] In this way, when considering the operation and stability of the inverter to drive the resonant circuit, it is preferable to drive it at a frequency that lags behind the resonant point, i.e., at a frequency higher than the resonant frequency.

[0323] Furthermore, in the case of the power supply device of this application, the following situation is also considered: since the Q value is quite high, it cannot resonate when the frequency deviates slightly from the resonant frequency, so capacitive or inductive loads cannot work normally.

[0324] This is a design issue that requires sacrificing the Q value to some extent to ensure controllability, or allowing for changes in circuit constants during operating conditions and aging.

[0325] The power supply device of this application can be used in various situations such as AC voltage source, AC current source, series resonance, parallel resonance, inductive load, capacitive load, voltage detection, and current detection.

[0326] Although only a small portion of the combinations are shown in Embodiments 1 to 8, they can be applied to other similar combinations.

[0327] Regarding applications, the description primarily focuses on inductive and capacitive loads. Particular emphasis is placed on barrier discharge loads such as ozone generators, which exhibit characteristic features due to discharge. However, applications can also be used for other general capacitive and inductive loads.

[0328] Furthermore, it may also be applicable to resonant converters that utilize resonance and contactless power supply.

[0329] This application describes various exemplary embodiments and examples, but the various features, forms and functions described in one or more embodiments are not limited to the application in a specific embodiment, but can be applied to the embodiments alone or in various combinations.

[0330] Therefore, numerous variations not illustrated are contemplated within the scope of the technology disclosed in this application. These include variations, additions, or omissions of at least one constituent element, as well as extraction of at least one constituent element and combination with constituent elements of other embodiments.

Claims

1. A power supply device comprising: a capacitive load having an equivalent capacitor and an equivalent resistance; and an AC power source applying an AC voltage to the capacitive load, wherein... The power supply device is as follows: a series circuit of the first inductor and the first capacitor is connected to the AC power source; a series circuit of the load inductor and the capacitive load is connected in parallel to either the first inductor or the first capacitor. The power supply device is as follows: a parallel circuit of the first inductor and the first capacitor is connected to the AC power source, and a parallel circuit of the load inductor and the capacitive load is connected in series to either the first inductor or the first capacitor. The power supply device has the following structure: Let the inductance of the first inductor be Lp, the capacitance of the first capacitor be Cp, the inductance of the load inductor be Ls, the equivalent capacitance of the capacitive load be Cs, and the frequency of the AC power supply be fv. Satisfying the following equations (6) and (7): 0.8 / ((2π·fv)^2)<Lp·Cp<1.2 / ((2π·fv)^2)(6) 0.8 / ((2π·fv)^2)<Ls·Cs<1.2 / ((2π·fv)^2)(7).

2. The power supply device according to claim 1, wherein, It includes an adjustment mechanism that allows at least one of the inductance or capacitance of the first inductor, the electrostatic capacitance of the first capacitor, and the inductance of the load inductor to be variable.

3. The power supply device according to claim 1, wherein, It includes a control circuit that controls the frequency of the AC power supply. The device includes a detection circuit that detects either the voltage or the current of the capacitive load, or both, while the frequency of the AC power supply is controlled to maximize either the voltage or the current. Alternatively, a detection circuit may be included, which detects the output voltage and output current of the AC power supply, wherein the frequency of the AC power supply is controlled to minimize the phase difference between the output voltage and the output current.

4. The power supply device according to claim 1, wherein, It includes a control circuit that controls the frequency of the AC power supply. It includes a storage unit that stores the relationship between the operating conditions of the capacitive load and the optimal value of the frequency of the AC power supply. When the power supply device starts working or when the operating conditions change, the frequency of the AC power supply is set to the optimal value accordingly.

5. A power supply device comprising: an inductive load having an equivalent inductor and an equivalent resistance; and an AC power source applying an AC voltage to the inductive load, wherein... The power supply device is as follows: a parallel circuit of the first inductor and the first capacitor is connected to the AC power source; a parallel circuit of the load capacitor and the inductive load is connected in series to either the first inductor or the first capacitor. The power supply device is as follows: a series circuit of the first inductor and the first capacitor is connected to the AC power source, and a series circuit of the load capacitor and the inductive load is connected in parallel to either the first inductor or the first capacitor. The power supply device has the following structure: When the inductance of the first inductor is Lp, the capacitance of the first capacitor is Cp, the capacitance of the load capacitor is Cs, the inductance of the inductive load is Ls, and the frequency of the AC power supply is fv, Satisfying the following equations (6) and (7): 0.8 / ((2π·fv)^2)<Lp·Cp<1.2 / ((2π·fv)^2)(6) 0.8 / ((2π·fv)^2)<Ls·Cs<1.2 / ((2π·fv)^2)(7).

6. The power supply device according to claim 5, wherein, It includes an adjustment mechanism that allows at least one of the inductance or capacitance of the first inductor, the electrostatic capacitance of the first capacitor, and the electrostatic capacitance of the load capacitor to be variable.

7. The power supply device according to claim 5, wherein, It includes a control circuit that controls the frequency of the AC power supply. The system includes a detection circuit that detects either the voltage or the current of the inductive load, or both, while the frequency of the AC power supply is controlled to maximize either the voltage or the current. Alternatively, a detection circuit may be included, which detects the output voltage and output current of the AC power supply, wherein the frequency of the AC power supply is controlled to minimize the phase difference between the output voltage and the output current.

8. The power supply device according to claim 5, wherein, It includes a control circuit that controls the frequency of the AC power supply. It includes a storage unit that stores the relationship between the operating conditions of the inductive load and the optimal value of the frequency of the AC power supply. When the power supply starts working or when the operating conditions change, the frequency of the AC power supply is set to the optimal value accordingly.

9. A power supply device comprising: a capacitive load having an equivalent capacitor and an equivalent resistance; and an AC power source applying an AC voltage to the capacitive load, wherein... The power supply device is as follows: The series circuit of the first inductor and the first capacitor is connected to the AC power supply. And n is an integer greater than or equal to 2, the series circuit of the nth inductor and the nth capacitor is connected in parallel to either the (n-1)th inductor or the (n-1)th capacitor. The series circuit of the load inductor and the capacitive load is connected in parallel to either the nth inductor or the nth capacitor. The power supply device has the following structure: the resonant frequency of the first inductor and the first capacitor, the resonant frequency of the second inductor and the second capacitor, ..., the resonant frequency of the nth inductor and the nth capacitor are the same as the resonant frequency of the load inductor and the capacitive load, and the frequency of the AC power supply is the same as the resonant frequency.

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