Processing device, processing method, and program

Abstract

To enable adjustment for impedance of a circuit according to reactance change of a load so that reactive power becomes small.SOLUTION: A processing device 110 calculates an L1 change amount based on input impedance Zin of a circuit 120 and an actual value of inductance L1, and directs operation based on the L1 change amount to an actuator 131.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a processing device, a processing method, and a program, and is particularly suitable for use in controlling the impedance of a circuit. [Background technology]

[0002] In order to reduce reactive power, it is desirable to supply power to a load with the circuit in a state close to a resonant state (preferably in a resonant state). If the reactance of the circuit is known, the resonant frequency can be uniquely determined. However, if the reactance of the load is not known, it is not easy to set an accurate resonant frequency in advance.

[0003] For example, when an induction heating device is used as a load, the reactance of the load is the combined reactance of the coil reactance of the induction heating device and the reactance of the metal plate to be heated. It is not easy to grasp the exact reactance of the metal plate in advance. Therefore, it is conceivable to adjust the reactance of the circuit so that the circuit approaches a resonant state while AC power is being supplied to the load.

[0004] As this type of technology, Patent Documents 1 and 2 disclose a technology for adjusting the inductance of a variable inductance coil when AC power is supplied from a voltage-type inverter to a circuit in which a variable inductance coil and a resonance capacitor are connected to a heating coil of an induction heating device. Specifically, an appropriate range of the value of the output power / output current of the voltage-type inverter with respect to the output current of the voltage-type inverter circuit is set in advance. Then, based on the detected values ​​of the output power and output current of the voltage-type inverter, the inductance of the variable inductance coil is changed so that the value of the output power / output current of the voltage-type inverter circuit with respect to the output current of the voltage-type inverter falls within the aforementioned appropriate range.

[0005] Patent Document 3 discloses a technique for changing the drive frequency of an inverter when supplying power from the inverter to the heating coil of an IH cooking heater. Specifically, the inductance of the heating coil is calculated based on the voltage of the heating coil, and the drive frequency of the inverter is adjusted so that the calculated inductance approaches a reference value. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2001-176649 A [Patent Document 2] JP 2004-30965 A [Patent Document 3] JP 2022-168426 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the techniques described in Patent Documents 1 and 2, it is necessary to set the appropriate range in advance. In addition, the appropriate range may vary significantly depending on the impedance (inductance, etc.) of the load (object to be heated). In this case, it is necessary to change the appropriate range in accordance with the load. However, it is not easy to accurately determine the appropriate range in accordance with the load having various reactances. In addition, in the technique described in Patent Document 3, it is necessary to set the reference value in advance. The reference value may also vary significantly depending on the impedance (inductance, etc.) of the load (object to be heated). In this case, it is necessary to change the reference value in accordance with the load. However, it is not easy to accurately determine the reference value in accordance with the load having various reactances.

[0008] As described above, in the techniques described in Patent Documents 1 to 3, when the load is changed, if the reference range or value is not appropriate for the changed load, the circuit may deviate significantly from the resonant state. Therefore, the techniques described in Patent Documents 1 to 3 have a problem in that they may not be able to adjust the impedance of the circuit so as to reduce reactive power in response to changes in the reactance of the load.

[0009] The present invention has been made in consideration of the above problems, and has an object to make it possible to adjust the impedance of a circuit in response to changes in the reactance of a load so as to reduce reactive power. [Means for solving the problem]

[0010] The processing device of the present invention is a processing device that performs processing to adjust the input impedance of a circuit including a power supply device and a load, and has an acquisition means for acquiring at least two actual values ​​of the output voltage, output current, and output power of the power supply device and an actual value of a variable reactance element in the circuit, an impedance calculation means for calculating the input impedance based on the at least two actual values, a variable reactance element calculation means for calculating an amount of change of the variable reactance element based on the input impedance calculated by the impedance calculation means and the actual value of the variable reactance element, and an instruction means for instructing an operation based on the amount of change of the variable reactance element to an operating end for changing the value of the variable reactance element while current is flowing through the circuit, and the variable reactance element is an element that can be manipulated by the operating end, among inductance, capacitance, and frequency.

[0011] The processing method of the present invention is a processing method for performing processing to adjust the input impedance of a circuit including a power supply device and a load, and includes an acquisition step of acquiring at least two actual values ​​of the output voltage, output current, and output power of the power supply device and an actual value of a variable reactance element in the circuit; an impedance calculation step of calculating the input impedance based on the at least two actual values; a variable reactance element calculation step of calculating an amount of change of the variable reactance element based on the input impedance calculated by the impedance calculation step and the actual value of the variable reactance element; and an instruction step of instructing an operation based on the amount of change of the variable reactance element to an operating end for changing the value of the variable reactance element while current is flowing through the circuit, wherein the variable reactance element is an element that can be manipulated by the operating end among inductance, capacitance, and frequency.

[0012] The program of the present invention causes a computer to function as each of the means of the processing device. Effect of the Invention

[0013] According to the present invention, the impedance of the circuit can be adjusted in response to changes in the reactance of the load so that reactive power is reduced. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram illustrating an example of a circuit configuration. [Diagram 2] FIG. 13 is a diagram illustrating an example of a relationship between input impedance and inductance. [Diagram 3] FIG. 2 illustrates an example of a functional configuration of a processing device. [Figure 4] FIG. 13 is a diagram illustrating an example of an L1 transformation function. [Diagram 5] 11 is a flowchart illustrating an example of a processing method. [Figure 6] FIG. 11 is a diagram showing an example of actual measurements of the relationship between input impedance and inductance and time. [Figure 7] FIG. 11 is a diagram showing an example of actual measurements of the relationship between input impedance and inductance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the term "the same thing" in terms of length, position, size, spacing, etc., includes things that are strictly the same, as well as things that are different within the scope of the invention (for example, things that differ within the tolerance range determined at the time of design).

[0016] <Circuit 120> FIG. 1 is a diagram showing an example of the configuration of a circuit 120 to which a processing device 110 of the present embodiment is applied. In FIG. 1, a circuit 120 includes a power supply device 121, an inductance variable device 122, a capacitor 123, and a load .

[0017] The power supply device 121 outputs AC power. The power supply device 121 is realized by, for example, an inverter power supply device. The inverter power supply device itself can be realized by using an AC power supply, a converter circuit, a smoothing capacitor, and an inverter circuit, as described in, for example, Patent Documents 1 to 3. Since the power supply device 121 itself can be realized by a known technology, detailed description of the power supply device 121 is omitted here. The power supply device 121 is not limited to an inverter power supply device. For example, the power supply device 121 may be configured using an AC stabilized power supply. In this embodiment, a case where the power supply frequency is fixed (unchanged) when AC power is supplied to the same load 124 is illustrated. The power supply frequency is the frequency of the AC voltage and AC current output from the power supply device 121. In this case, the power supply frequency may be fixed regardless of the load 124, or the power supply frequency may be changed for each load 124.

[0018] The inductance variable device 122 adjusts the inductance in the circuit 120. The inductance variable device 122 has a coil part and a magnetic core part, and can be realized by changing the value of the inductance according to the position of the magnetic core part relative to the coil part, as described in Patent Documents 1-2, for example. In this embodiment, the inductance (H) of the inductance variable device 122 is expressed as L1 as necessary. The inductance variable device 122 is operated by, for example, an actuator 131. When the inductance variable device 122 has a coil part and a magnetic core part as described in Patent Documents 1-2, the actuator 131 moves the magnetic core part forward and backward relative to the hollow area of ​​the coil part within a preset moving range, as described in Patent Documents 1-2. As described above, the inductance variable device 122 and the actuator 131 themselves can be realized by known techniques, so detailed explanations of the inductance variable device 122 and the actuator 131 are omitted here. In addition, the inductance variable device 122 and the actuator 131 are not limited to those described in Patent Documents 1 and 2, as long as they can actively change the inductance in the circuit 120. For example, an inductance adjustment device and a drive device described in JP-A-2018-012354 may be used as the inductance variable device 122 and the actuator 131, respectively.

[0019] The capacitor 123 has a fixed capacitance (constant value). The capacitor 123 is a capacitor for resonating the circuit 120. In this embodiment, the capacitance (F) of the capacitor is represented as C as necessary. The load 124 consumes the AC power output from the power supply device 121. In this embodiment, the load 124 is an inductive load. The load 124 includes a heating coil for induction heating an object to be heated, as in Patent Documents 1 to 3. The object to be heated is, for example, a plurality of metal strips being transported in a state in which the rear end of a preceding metal strip (metal plate) and the front end of a succeeding metal strip are connected to each other by welding or the like. In this case, the plurality of metal strips (metal plates) are continuously induction heated. Note that the object to be heated is not limited to such a metal strip (metal plate). For example, when the circuit 120 constitutes an IH cooking heater as described in Patent Document 3, the object to be heated is a metal pot or the like. In addition, the object to be heated is not limited to an object to be induction heated. For example, the object to be heated may be an object to be heated by welding. In this case, the load 124 includes a welding machine (for example, an electrode) and an object to be heated (an object to be welded). When the load 124 includes an object to be heated, the impedance of the load 124 differs depending on the impedance of the object to be heated.

[0020] Furthermore, the load 124 is not limited to one including a heating device and an object to be heated. For example, the load 124 may include a rolling mill (e.g., a reduction device) and an object to be rolled. When the load 124 includes an object to be rolled (e.g., a steel material), the impedance of the load 124 differs depending on the impedance of the object to be rolled.

[0021] Furthermore, the load 124 is not limited to an inductive load. That is, the load 124 may be a capacitive load. For example, when an insulator, which is an object to be heated, is dielectrically heated, the load 124 becomes a capacitive load. In this case, the load 124 includes an electrode and an object to be heated (insulator). Even when the object to be heated is dielectrically heated, the impedance of the load 124 differs depending on the impedance of the object to be heated. As described above, the load 124 is not limited to a specific load as long as the impedance (reactance) of the load 124 can change when some or all of the components of the load 124 are changed.

[0022] In the following description, the resistance (Ω) of the load 124 will be represented as R as necessary. Also, the inductance (H) of the load 124 will be represented as L2 as necessary. Note that the resistance R is the value of the real part when the impedance is expressed in complex numbers (complex impedance). In addition, in this embodiment, the case where the resistance R of the load 124 is the combined resistance of the object to be heated and the heating coil is illustrated. In addition, in this embodiment, the case where the inductance L2 of the load 124 is the combined inductance of the object to be heated and the heating coil is illustrated. Therefore, the impedance of the load 124 is the combined impedance of the object to be heated and the heating coil.

[0023] For ease of explanation, it is assumed here that the capacitance of the load 124 is 0 (zero). However, the capacitance of the load 124 may be greater than 0 (zero). As described above, this embodiment illustrates a case in which the load 124 is an inductive load. Therefore, the inductive reactance of the load 124 is greater than the capacitive reactance of the load 124. Therefore, even if the capacitance of the load 124 is greater than 0 (zero), the positive / negative sign of the reactance of the load 124 is the same as when the capacitance of the load 124 is 0 (zero).

[0024] 1, this embodiment illustrates a case in which a variable inductance device 122, a capacitor 123, and a load 124 are connected in series to a power supply device 121. That is, this embodiment illustrates a case in which a series resonant circuit is configured by the power supply device 121, the variable inductance device 122, the capacitor 123, and the load 124.

[0025] In addition, in this embodiment, a case is illustrated in which a voltmeter 132 that measures the output voltage of the power supply device 121 (in the example shown in FIG. 1, the sum of the voltages applied to the variable inductance device 122, the capacitor 123, and the load 124) is installed in the circuit 120. In addition, in this embodiment, a case is illustrated in which an ammeter 133 that measures the output current of the power supply device 121 (in the example shown in FIG. 1, the current flowing through the variable inductance device 122, the capacitor 123, and the load 124) is installed in the circuit 120. The ammeter 133 may be a clamp-type ammeter, or may be an ammeter that is directly connected to the electric wires of the circuit. The clamp-type ammeter has, for example, a CT (Current Transformer).

[0026] The processing device 110 performs processing for adjusting the input impedance of the circuit 120 including the power supply device 121 and the load 124. Note that Fig. 1 illustrates an example in which the circuit 120 has an output circuit having the power supply device 121, and an input circuit having the inductance variable device 122, the capacitor 123, and the load 124. Therefore, Fig. 1 illustrates an example in which the input impedance (the impedance of the input circuit) is the composite impedance of the inductance variable device 122, the capacitor 123, and the load 124. Note that the input impedance is the impedance when the load 124 side is viewed from the power supply device 121.

[0027] <Background and findings> Here, the circumstances leading to the present embodiment and the knowledge gained when arriving at the present embodiment will be described with reference to the circuit 120 shown in FIG. 1, a series resonant circuit is formed by the power supply device 121, the variable inductance device 122, the capacitor 123, and the load 124. Therefore, the resonant frequency f2 of the circuit 120 shown in FIG. 1 is expressed by the following equation (1).

[0028]

number

[0029] In formula (1), the inductance L2 of the load 124 is the combined inductance of the object to be heated and the heating coil. The inductance of the object to be heated varies depending on the attributes of the object to be heated. When the object to be heated is the above-mentioned metal strip, the inductance of the metal strip varies depending on the type, thickness, and width of the metal strip. Meanwhile, the inductance L1 can be changed by the inductance variable device 122 (actuator 131) while the circuit 120 is energized. Therefore, even if the inductance L2 of the load 124 varies, the resonance state of the circuit 120 can be maintained by changing the inductance L1 so that the resonance frequency f2 of formula (1) does not vary. However, there are cases where the inductance of the object to be heated cannot be accurately determined in advance (or is not easy). For example, when multiple metal strips are continuously induction heated, it is not easy to determine the fluctuation in the inductance of the metal strips during operation by measurement or the like. On the other hand, as mentioned above in the section on the problems that the invention aims to solve, when changing the inductance so that it becomes (or approaches) a range or value according to the load (heated object), as described in Patent Documents 1 to 3, it is not easy to accurately determine the range or value according to the load (heated object).

[0030] Therefore, the present inventors have investigated a method for adjusting the reactance without using a criterion that needs to be changed depending on the load. First, the inventors have noted that the input impedance of a circuit is minimum or maximum (reactance is 0 (zero)) when the circuit is in a resonant state. For example, in the case of an RLC series resonant circuit, the input impedance of the circuit is minimum when the circuit is in a resonant state. The inventors then came up with the idea of ​​expressing the relationship between the input impedance of a circuit and a variable reactance element, using only the variable reactance element, which is an element that can be manipulated by an operating terminal among the elements that constitute the reactance, as a variable. The inventors have noted that, in this relationship, the input impedance of the circuit peaks at the value of the variable reactance element when the circuit is in a resonant state. When the resonant circuit is an RLC series resonant circuit, in this relationship, the input impedance of the circuit is minimum (i.e., a local minimum value) at the value of the variable reactance element when the circuit is in a resonant state.

[0031] In the circuit 120 shown in FIG. 1, the variable reactance element is an inductance L1. In this case, when the power supply frequency and the capacitance C of the capacitor 123 are constant, the input impedance Z of the circuit 120 is in The relationship between the inductance L1 and the input impedance Z of the circuit 120 is shown in FIG. in As shown in the graph 201, the input impedance Z of the circuit 120 is in is expressed as an irrational function in which the coefficient of the quadratic term in the root (the coefficient related to the inductance L1) is a positive value. In the following description, an irrational function that is a function of the inductance L1 and in which the coefficient of the quadratic term in the root is a positive value will be abbreviated as an irrational function as necessary.

[0032] In this case, if an inductance L1 is found at a position where a peak 202 is shown in the irrational function represented by the graph 201, the circuit 120 will be in a resonant state. inThe relationship between and inductance L1 is expressed by an irrational function with a positive coefficient of the quadratic term in the root, as in graph 201, even if the inductance L2 of load 124 changes. Therefore, even if the inductance L2 of load 124 changes, the inductance L1 at which circuit 120 resonates is the inductance L1 at the position showing a peak in the irrational function (graph 201). Therefore, the condition for putting circuit 120 into a resonant state (searching for inductance L1 at the position showing peak 202) can be made the same regardless of load 124.

[0033] As described above, the inventors have found that even if the inductance L2 of the load 124 changes, the inductance L1 for putting the circuit 120 into a resonant state is the inductance L1 at the position showing the peak 202 in the irrational function represented by the graph 201. In this way, the condition for putting the circuit 120 into a resonant state (searching for the inductance L1 at the position showing the peak 202) does not change depending on the load 124. Therefore, it is possible to search for the inductance L1 for putting the circuit 120 into a resonant state without changing the reference range or value depending on the load 124.

[0034] Here, for example, the circuit 120 does not have to be in a resonant state by changing the inductance L1 once. Also, the reactive power of the circuit 120 can be reduced without exactly bringing the circuit 120 into a resonant state. Therefore, the inductance L1 may be changed so that the circuit 120 approaches the resonant state (without (exactly) bringing the circuit 120 into a resonant state). When bringing the circuit 120 closer to the resonant state, for example, the inductance L1 is changed so that it approaches the position showing the peak 202 in the irrational function represented by the graph 201. In this case, the reference range or value may or may not be changed depending on the load 124. The condition for bringing the circuit 120 into a resonant state (searching for the inductance L1 at the position showing the peak 202) does not change depending on the load 124. Therefore, even when the reference range or value is changed depending on the load 124, the reference range or value can be easily determined compared to Patent Documents 1 to 3.

[0035] Next, a description will be given of findings regarding how to preferably change the inductance L1 when searching for the inductance L1 at the position showing the peak 202 (or a position close to the peak 202) in the irrational function represented by the graph 201.

[0036] In the example shown in FIG. 2, the input impedance Z of the circuit 120 is changed as a result of changing the inductance L1 before the change. in When the inductance L1 changes from a decrease to an increase (or from an increase to a decrease), a peak 202 is present between the inductance L1 before and after the change. in When the inductance L1 is increased, the input impedance Z of the circuit 120 is closer to the position showing the peak 202 than the inductance L1 before the change. in When the inductance L1 is changed, the inductance L1 after the change is closer to the position showing the peak 202 than the inductance L1 before the change. Therefore, when the inductance L1 is changed, the magnitude relationship of the inductance L1 and the input impedance Z of the circuit 120 are in Based on the magnitude relationship between in The inductance L1 can be changed so that

[0037] In this way, the input impedance Z of the circuit 120 when the inductance L1 is changed in It may be possible to determine whether to increase or decrease the inductance L1 by judging the magnitude relationship between the inductance L1 and the input impedance Z based on the graph 201. In addition, when the inductance L1 is changed, for example, in the direction approaching the peak 202 (i.e., the input impedance Z in Alternatively, the inductance L1 may be changed by a predetermined value so that the inductance L2 decreases.

[0038] However, the reactive power of the circuit 120 cannot be sufficiently reduced until the inductance L1 approaches the peak 202. Therefore, the present inventors have investigated a method for changing the inductance L1 more efficiently. First, the inventors calculated the input impedance Z of the circuit 120 with respect to the time change (amount of change per unit time) of the inductance L1. in In the following description, the input impedance Z of the circuit 120 with respect to the time change of the inductance L1 is focused on. in The slope expressed as the ratio of the time change of is referred to as the slope of the graph 201 as necessary.

[0039] If the inductance L1 is decreased when the slope of the graph 201 is positive (>0), and if the inductance L1 is increased when the slope is negative (<0), the inductance L1 approaches the peak 202 (i.e., the input impedance Z in In this way, the inventors have found that it is preferable to use the slope of the graph 201, since it is possible to determine whether to increase or decrease the inductance L1 by determining the sign of the slope of the graph 201.

[0040] The inventors also determined that the input impedance Z of the circuit 120, as shown in FIG. inHowever, the inventors have noticed that the coefficient of the quadratic term in the root (coefficient related to the inductance L1) is expressed as a positive irrational function. That is, the inventors have noticed that the absolute value of the slope of the graph 201 increases as the inductance L1 deviates from the position showing the peak 202 in the graph 201. When the absolute value of the slope of the graph 201 at the current value of the inductance L1 is large, the absolute value of the change amount of the inductance L1 can be increased as the current value of the inductance L1 is far from the position showing the peak 202 in the graph 201, and when the absolute value of the slope of the graph 201 is small, the absolute value of the change amount of the inductance L1 can be decreased as the current value of the inductance L1 is close to the position showing the peak 202 in the graph 201. In this way, the inventors have found that it is preferable to use the slope of the graph 201 because the absolute value (magnitude) of the change amount of the inductance L1 can be determined based on the absolute value (magnitude) of the slope of the graph 201.

[0041] As described above, the present inventors have found that the slope of the graph 201 includes an index for determining whether to increase or decrease the inductance L1 and an index for determining the amount of change (absolute value) of the inductance L1. Specifically, the present inventors have found that it is preferable to determine whether to increase or decrease the inductance L1 based on the sign of the slope of the graph 201, and that it is preferable to calculate the amount of change (absolute value) of the inductance L1 based on the magnitude (absolute value) of the slope of the graph 201.

[0042] Here, the circuit 120 shown in FIG. 2 is exemplified, and the case where the variable reactance element is only an inductance and the resonant circuit is an RLC series resonant circuit is described. However, the relationship between the input impedance of the circuit and the variable reactance element can be obtained even when the variable reactance element is not only an inductance and when the resonant circuit is not a series resonant circuit. Therefore, the variable reactance element is not limited to only an inductance, and for example, instead of inductance, a frequency (power supply frequency) or a capacitance may be used as the variable reactance element, or two or more types of elements (at least two of inductance, capacitance, and frequency) may be used as the variable reactance element. If the number of types of variable reactance elements is small, the configuration and calculation of the circuit can be simplified. From this point of view, it is preferable that the variable reactance element is one type. On the other hand, if there are multiple types of variable reactance elements, it becomes possible to select the variable reactance element to be changed according to the load, or to change multiple types of variable reactance elements at once to greatly change the input impedance at once.

[0043] Moreover, which of the inductance, capacitance, and frequency is to be the variable reactance element may be determined according to, for example, a configuration for actively changing the value of the element. For example, when an inverter power supply device is used as the power supply device 121, performing frequency control may increase the cost of the power supply device. In such a case, the frequency (power supply frequency) may not be included in the variable reactance element. Also, for example, when it is easier to adjust the inductance than to adjust the capacitance, the capacitance may not be included in the variable reactance element. Conversely, when it is easier to adjust the capacitance than to adjust the inductance, the inductance may not be included in the variable reactance element.

[0044] Furthermore, if a capacitance exists in circuit 120, such as a line capacitance of a coil, and the resonant frequency can be calculated without installing capacitor 123, then capacitor 123 may not be installed in circuit 120. Furthermore, if inductance is not included in the variable reactance element, for example, if an inductance exists in the circuit, such as a load inductance, and the resonant frequency can be calculated without installing an inductor, then an inductor may not be installed in the circuit.

[0045] Moreover, the resonant circuit is not limited to an RLC series resonant circuit, and may be, for example, an RLC parallel resonant circuit or an RLC series-parallel resonant circuit. In a circuit having a plurality of resonant frequencies, a plurality of peaks exist in the relationship between the input impedance of the circuit and the variable reactance element. In this case, for example, the value of the variable reactance element may be changed so that the value of the variable reactance element becomes a value at a position indicating one of the plurality of peaks, or approaches the peak. The target peak of the value of the variable reactance element may be, for example, predetermined from the form of a function indicating the relationship between the input impedance of the circuit and the variable reactance element, or may be the peak closest to the current value of the variable reactance element. In addition, for example, at the current value of the variable reactance element, the input impedance of the circuit may be second-order differentiated with the variable reactance element (calculating the time change in the slope of the graph 201) to determine whether the current value of the variable reactance element is in a downward convex region or an upward convex region.

[0046] The processing apparatus 110 and processing method of this embodiment, which will be described below, have been developed based on the above circumstances and findings.

[0047] <Processing device 110> 3 is a diagram showing an example of a functional configuration of the processing device 110. The processing device 110 has one or more hardware processors such as a CPU (Central Processing Unit), one or more memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and executes various calculations by executing one or more programs stored in the memory by the one or more hardware processors. Furthermore, the processing device 110 has an input device and an output device. In this embodiment, a case where the functions of the processing device 110 are realized by using software (execution of a program) is illustrated. However, at least a part of the functions of the processing device 110 may be realized without using software (by hardware).

[0048] 3, the processing device 110 includes an acquisition unit 111, an impedance calculation unit 112, a variable reactance element calculation unit 113, and an instruction unit 114.

[0049] <<Acquisition part 111>> The acquiring unit 111 acquires at least two actual values ​​of the output voltage, the output current, and the output power of the power supply device 121 and an actual value of the variable reactance element in the circuit 120.

[0050] In this embodiment, a case will be illustrated in which the acquisition unit 111 acquires the voltage measured by the voltmeter 132 as the actual value of the output voltage of the power supply device 121, and acquires the current measured by the ammeter 133 as the actual value of the output current of the power supply device 121. In the following description, the actual value of the output voltage of the power supply device 121 will be referred to as the actual voltage value as necessary. Also, the actual value of the output current of the power supply device 121 will be referred to as the actual current value as necessary.

[0051] The acquiring unit 111 may acquire the actual voltage value and the actual current value directly from the voltmeter 132 and the ammeter 133, or may acquire them from a device other than the voltmeter 132 and the ammeter 133. In the former case, the processing device 110 (acquiring unit 111) performs wired or wireless communication with the voltmeter 132 and the ammeter 133. In the latter case, the processing device 110 (acquiring unit 111) performs wired or wireless communication with a device other than the voltmeter 132 and the ammeter 133.

[0052] In the present embodiment, the acquisition unit 111 repeatedly acquires the actual voltage value and the actual current value in a first cycle. The first cycle is set in advance based on the processing capabilities (clock frequency) of the voltmeter 132, the ammeter 133, and the processing device 110, for example.

[0053] The acquisition unit 111 may acquire an actual value of the output power of the power supply device 121 instead of or in addition to one of the actual voltage value and the actual current value. In this case, a power meter that measures the output power of the power supply device 121 is installed in the circuit 120. In this way, it is sufficient for the acquisition unit 111 to acquire at least two of the actual value of the output power, the actual value of the output current, and the actual value of the output power of the power supply device 121 so that the input impedance of the circuit 120 can be calculated.

[0054] In addition, in this embodiment, a case will be illustrated in which the acquiring unit 111 acquires the actual value of the inductance L1 as an example of the actual value of the variable reactance element in the circuit.

[0055] The variable reactance element is an element that can be manipulated by an operating end among the elements that constitute reactance. The elements that constitute reactance are inductance, capacitance, and frequency. In this embodiment, a case is illustrated in which the element that can be manipulated by an operating end among inductance, capacitance, and frequency is only inductance. Specifically, in this embodiment, a case is illustrated in which the actual value of the variable reactance element in the circuit 120 is the actual value of the inductance L1. As described above in the <Background and Findings> section, the variable reactance element is not limited to inductance. In the following description, the actual value of the inductance L1 is referred to as the inductance actual value as necessary.

[0056] In addition, in this embodiment, a case where the actuator 131 is an operated end is illustrated. In addition, in this embodiment, a case where the operation amount of the actuator 131 corresponds to the actual value of the inductance L1 is illustrated. Therefore, the acquisition unit 111 may acquire the actual value of the operation amount of the actuator 131, instead of the actual value of the inductance L1 itself, and may acquire the inductance actual value by converting the operation amount of the actuator 131 into inductance.

[0057] The actual inductance value may be the value of the inductance L1 itself or a relative value. For example, the actual inductance value may be expressed as a value (%) based on the maximum value of the inductance L1 that can be realized by the inductance variable device 122 (=100%).

[0058] The acquisition unit 111 may acquire the actual inductance value directly from the actuator 131, or may acquire it from a device other than the actuator 131 (and the inductance variable device 122). In the former case, the processing device 110 (acquisition unit 111) performs wired or wireless communication with the actuator 131. In the latter case, the processing device 110 (acquisition unit 111) performs wired or wireless communication with a device other than the actuator 131. The acquisition unit 111 may also acquire the actual inductance value from the inductance variable device 122. In this case, the processing device 110 (acquisition unit 111) performs wired or wireless communication with the inductance variable device 122.

[0059] In addition, in this embodiment, a case where the acquisition unit 111 repeatedly acquires the inductance actual value in a second period is illustrated. The second period is set in advance, for example, based on the processing capabilities (clock frequency) of the actuator 131 and the processing device 110. In this embodiment, for the sake of simplicity, a case where the first period and the second period are the same and the acquisition unit 111 repeatedly acquires the voltage actual value, the current actual value, and the inductance actual value at the same timing is illustrated. However, the acquisition unit 111 may acquire two or three of the voltage actual value, the current actual value, and the inductance actual value at different timings. In this case, when the period from the acquisition timing of the first acquired actual value of the voltage actual value, the current actual value, and the inductance actual value to the acquisition timing of the last acquired actual value is within a predetermined period, the acquisition unit 111 may treat the voltage actual value, the current actual value, and the inductance actual value acquired during that period as a set of actual values ​​(in this case, the set of actual values ​​is treated in the same manner as the actual values ​​of the same period described in this embodiment).

[0060] <<Impedance Calculation Unit 112>> The impedance calculation unit 112 calculates the input impedance of the circuit 120 based on at least two actual values ​​of the output voltage, output current, and output power of the power supply device 121. As described above, in this embodiment, a case is exemplified in which the acquisition unit 111 acquires the actual voltage value and the actual current value. Therefore, the impedance calculation unit 112 calculates the input impedance of the circuit 120 based on the actual voltage value and the actual current value. As described above, in this embodiment, a case is exemplified in which the acquisition unit 111 acquires the actual voltage value and the actual current value in a first period. Therefore, in this embodiment, a case is exemplified in which the impedance calculation unit 112 repeatedly calculates the input impedance of the circuit 120 in a first period based on the actual voltage value and the actual current value acquired in the same period by the acquisition unit 111. The input impedance (Ω) of the circuit 120 is expressed as Z in If the actual voltage value (V) is V, the actual current value (A) is I, and the power supply frequency (Hz) is f1, then the input impedance Z of the circuit 120 is in is expressed by the following equation (2).

[0061]

number

[0062] As shown in equation (2), in this embodiment, the impedance calculation unit 112 calculates the impedance Z of the circuit 120 by dividing the actual voltage value V by the actual current value I. in The case of calculating the following will be exemplified.

[0063] <<Variable reactance element calculation unit 113>> The variable reactance element calculation unit 113 calculates the input impedance Z inand the actual value of the variable reactance element acquired by the acquisition unit 111. As described above, in this embodiment, the element that can be manipulated by the manipulated terminal among the inductance, capacitance, and frequency is only the inductance, and the acquisition unit 111 acquires the inductance actual value. Therefore, in this embodiment, the variable reactance element calculation unit 113 calculates the change amount of the variable reactance element based on the input impedance Z in 10 and the inductance actual value acquired by the acquisition unit 111.

[0064] As described above, in this embodiment, the acquisition unit 111 repeatedly acquires the voltage actual value V, the current actual value I, and the inductance actual value at the same timing (first period (=second period)). Therefore, in this embodiment, the variable reactance element calculation unit 113 acquires the input impedance Z calculated based on the inductance actual value and the voltage actual value V and the current actual value I acquired in the same period as the period in which the inductance actual value was acquired. in A case will be illustrated in which the calculation of the change amount of the inductance L1 based on the above is repeatedly performed in a first period (=second period).

[0065] In this embodiment, the variable reactance element calculation unit 113 calculates the input impedance Z in 1, and the actual value of the variable reactance element. As described above, the slope of the graph 201 is determined by the input impedance Z inThe inductance L1 is expressed as a ratio of the time change of the inductance L1. In the present embodiment, the variable reactance element calculation unit 113 calculates the inductance of the graph 201 repeatedly in the first period (=second period). In this case, the time change is expressed by, for example, a value obtained by subtracting a value in the period immediately before the period to which the current time belongs from a value in the period to which the current time belongs. In the present embodiment, the variable reactance element calculation unit 113 calculates the inductance of the graph 201 in this way to specify the sign of the inductance of the graph 201, and determines whether to increase or decrease the inductance L1 based on the sign of the inductance of the graph 201. Specifically, in the example shown in FIG. 2, when the inductance of the graph 201 is negative, the variable reactance element calculation unit 113 determines to increase the inductance L1, and when the inductance of the graph 201 is positive, the variable reactance element calculation unit 113 determines to decrease the inductance L1.

[0066] In addition, in this embodiment, a case is illustrated in which the variable reactance element calculation unit 113 calculates the change amount of inductance L1 based on the absolute value (magnitude) of the slope of graph 201. In the following description, the change amount of inductance L1 is referred to as the L1 change amount as necessary. In this embodiment, a case is illustrated in which the variable reactance element calculation unit 113 repeatedly calculates the L1 change amount in a first period (=second period). Note that the variable reactance element calculation unit 113 may calculate the value of the changed inductance L1 based on the current value of inductance L1 and the L1 change amount. Note that the above-mentioned current value is, for example, a value in the period to which the current time belongs.

[0067] In this embodiment, when the inductance L1 after the change is larger than the inductance L1 before the change, the L1 change amount has a positive value, and when the inductance L1 after the change is smaller than the inductance L1 before the change, the L1 change amount has a negative value. That is, in this embodiment, the L1 change amount is represented by a value obtained by subtracting the inductance L1 before the change from the inductance L1 after the change.

[0068] In the present embodiment, the variable reactance element calculation unit 113 prestores information indicating the correspondence between the slope of the graph 201 and the L1 change amount, and calculates the L1 change amount based on the slope of the graph 201 calculated as described above and the information. The information indicating the correspondence between the slope of the graph 201 and the L1 change amount is, for example, a function of the L1 change amount that expresses the slope of the graph 201. The information indicating the correspondence between the slope of the graph 201 and the L1 change amount may be expressed by a relational expression (mathematical expression) indicating the relationship between the slope of the graph 201 and the L1 change amount, or may be a table that stores the slope of the graph 201 and the L1 change amount in association with each other. In the following description, the information indicating the correspondence between the slope of the graph 201 and the L1 change amount is referred to as an L1 conversion function as necessary.

[0069] Fig. 4 is a diagram showing an example of the L1 transformation functions 401 to 403. Note that Fig. 4 illustrates a case where all of the L1 transformation functions 401 to 403 are continuous functions and odd functions. FIG. 4(a) is a diagram showing a first example of an L1 conversion function 401. The L1 conversion function 401 shown in FIG. 4(a) is determined so that the absolute value of the L1 change amount increases as the absolute value of the slope of the graph 201 increases. As described above, in this embodiment, the L1 change amount is represented by a value obtained by subtracting the inductance L1 before the change from the inductance L1 after the change. In addition, the input impedance Z of the circuit 120 is in is expressed as a function of inductance L1, the function becomes an irrational function with a positive coefficient for the quadratic term in the root (see graph 201). Therefore, L1 conversion function 401 is determined so that the smaller the slope of graph 201, the larger the L1 change amount (so that the larger the slope of graph 201, the smaller the L1 change amount). More specifically, L1 conversion function 401 is determined so that the relationship between the L1 change amount and the slope of graph 201 is a directly proportional relationship with a negative proportionality coefficient. Note that the relationship between the L1 change amount and the slope of graph 201 in L1 conversion function 401 is not limited to a directly proportional relationship.

[0070] FIG. 4(b) is a diagram showing a second example of the L1 conversion function 402. The L1 conversion function 402 shown in FIG. 4(b) is defined such that when the slope of the graph 201 is within a predetermined range including 0 (zero) (when TH2 or more and TH1 or less (TH2 ≤ slope of graph 201 ≤ TH1)), the absolute value of the L1 change amount increases as the absolute value of the slope of the graph 201 increases. Specifically, when the slope of the graph 201 is within the predetermined range, the L1 conversion function 402 is defined such that the L1 change amount increases as the slope of the graph 201 decreases (the L1 change amount decreases as the slope of the graph 201 increases). More specifically, the L1 conversion function 402 when the slope of the graph 201 is within the predetermined range is the same as the L1 conversion function 401 shown in FIG. 4(a).

[0071] Further, when the slope of the graph 201 is not within the predetermined range (when the slope of the graph 201 < TH2, the slope of the graph 201 > TH1), the L1 conversion function 402 is defined such that the absolute value of the slope of the graph 201 is the same as the maximum value of the absolute value of the L1 change amount when the slope of the graph 201 is within the predetermined range (the L1 change amount at TH1 and TH2). That is, the L1 conversion function 402 is defined such that when the slope of the graph 201 is greater than the upper limit value (TH1) of the predetermined range, the L1 change amount is constant at the upper limit value. Also, the L1 conversion function 402 is defined such that when the slope of the graph 201 is less than the lower limit value (TH2) of the predetermined range, the L1 change amount is constant at the lower limit value.

[0072] FIG. 4(c) is a diagram showing a third example of the L1 conversion function 403. The L1 conversion function 403 shown in FIG. 4(c) is defined such that when the slope of the graph 201 is within a predetermined range including 0 (zero) (when TH4 or more and TH3 or less (TH4 ≤ slope of graph 201 ≤ TH3)), the absolute value of the L1 change amount increases as the absolute value of the slope of the graph 201 increases. Specifically, when the slope of the graph 201 is within the predetermined range, the L1 conversion function 403 is defined such that the L1 change amount increases as the slope of the graph 201 decreases (the L1 change amount decreases as the slope of the graph 201 increases). More specifically, the L1 conversion function 403 when the slope of the graph 201 is within the predetermined range is obtained by changing the values of the L1 change amounts near the upper limit value (TH3) and the lower limit value (TH4) of the predetermined range so as to be smooth (differentiable) with respect to the L1 conversion function 401 shown in FIG. 4(a). Note that the L1 conversion function 403 when the slope of the graph 201 is within the predetermined range may be the same as the L1 conversion function 401 shown in FIG. 4(a). That is, the L1 conversion function does not have to be smooth at the positions of the upper limit value (TH3) and the lower limit value (TH4) of the predetermined range of the slope of the graph 201.

[0073] Further, when the slope of the graph 201 is not within the predetermined range (when the slope of the graph 201 < TH4, when the slope of the graph 201 > TH3), the L1 conversion function 403 is defined such that the absolute value of the L1 change amount decreases as the absolute value of the slope of the graph 201 increases. As described above, in the present embodiment, an example is illustrated in which the L1 change amount is represented by a value obtained by subtracting the inductance L1 before the change from the inductance L1 after the change. Also, the input impedance Z of the circuit 120 inWhen expressed as a function of the inductance L1, the function becomes an irrational function with a positive coefficient for the quadratic term within the root (see Graph 201). Therefore, when the slope of Graph 201 is greater than the upper limit value (TH3) of the predetermined range, the L1 change amount is determined such that it increases (approaches 0 (zero)) as the slope of Graph 201 increases from the upper limit value. Also, when the slope of Graph 201 is less than the lower limit value (TH4) of the predetermined range, the L1 change amount is determined such that it decreases (approaches 0 (zero)) as the slope of Graph 201 decreases from the lower limit value. Note that in FIG. 4(c), when the slope of Graph 201 is not within the predetermined range (when the slope of Graph 201 < TH4, when the slope of Graph 201 > TH3), an example is shown where the L1 change amount changes non-linearly with respect to the change in the slope of Graph 201 and changes until the L1 change amount becomes 0 (zero). Note that this change does not have to be a non-linear change (i.e., it can be a linear change).

[0074] In addition, in this embodiment, the variable reactance element calculation unit 113 stores at least one of the L1 conversion functions 401 to 403 in advance. When the actual value of the inductance L1 fluctuates significantly temporarily due to the influence of noise or the like in the circuit 120, the absolute value of the slope of the graph 201 also fluctuates significantly. In such a case, if the L1 change amount is calculated based on the L1 conversion function 401 shown in FIG. 4(a), the circuit 120 may deviate from the resonant state. In such a case, it is preferable to use the L1 conversion function 402 shown in FIG. 4(b) so that the L1 change amount can be suppressed to a constant value, and it is more preferable to use the L1 conversion function 403 shown in FIG. 4(c) so that the L1 change amount can be suppressed to 0 (zero) or a value close to 0 (zero). Note that any one of the L1 conversion functions 401 to 403 may be selected depending on the circuit to which the processing device 110 is applied, etc. For example, when it is expected that the amount of change in L1 will be large due to a large change in inductance L2 of load 124 immediately after a component of load 124 (in this embodiment, a metal band) is changed, L1 conversion function 401 may be selected and then L1 conversion function 401 may be changed to L1 conversion function 402 or 403.

[0075] The upper limit (TH1, TH3) and the lower limit (TH2, TH4) of the predetermined range are set in advance based on an expected value of the change in the slope of the graph 201 in one cycle when there is no disturbance such as noise. The expected value of the change in the slope of the graph 201 in one cycle when there is no disturbance such as noise may be determined based on the result of a circuit simulation (simulating the operation of the circuit 120 by a computer) using values ​​actually used as the power supply frequency f1 and the capacitance C. The L1 conversion function is not limited to the L1 conversion functions 401 to 403 shown in FIG. 4. For example, when the absolute value of the L1 change amount is made larger as the absolute value of the slope of the graph 201 is larger, the L1 change amount may be changed stepwise with respect to the change in the slope of the graph 201 (i.e., there may be a section in the middle where the L1 change amount is constant).

[0076] <<Instruction section 114>> The instruction unit 114 instructs an operation based on the change amount of the variable reactance element calculated by the variable reactance element calculation unit 113 to an operation terminal for changing the value of the variable reactance element. In this embodiment, a case where the operation terminal is the actuator 131 is illustrated. Also, in this embodiment, a case where the L1 change amount is calculated by the variable reactance element calculation unit 113 is illustrated. Therefore, in this embodiment, a case where the instruction unit 114 instructs the actuator 131 to operate based on the L1 change amount is illustrated. In the following description, an instruction given by the instruction unit 114 to the actuator 131 is referred to as an operation instruction as necessary. Based on this operation instruction, the actuator 131 operates the inductance variable device 122 so as to change the inductance L1 before the change (the current value of the inductance L1) by the L1 change amount.

[0077] When the variable reactance element calculation unit 113 calculates the value of the changed inductance L1 based on the current value of the inductance L1 and the L1 change amount, the instruction unit 114 may instruct the actuator 131 to perform an operation to change the inductance L1 to the changed inductance L1. Even in this case, the instruction unit 114 still instructs the actuator 131 to perform an operation based on the L1 change amount. When the inductance variable device 122 has a function as an actuator (operated end), the instruction unit 114 may instruct the inductance variable device 122 to perform an operation based on the L1 change amount. In this case, the actuator 131 may not be provided.

[0078] As described above in the section <<Variable reactance element calculation unit 113>>, in this embodiment, the variable reactance element calculation unit 113 calculates the L1 change amount repeatedly in the first period (= second period). The instruction unit 114 may repeatedly issue an operation instruction in the first period, for example. However, depending on the configuration of the inductance variable device 122, it may not be possible (or it may not be easy) to operate the inductance variable device 122 in a short period. In addition, if the inductance L1 is frequently changed, there is a risk that the control for supplying power to the load 124 (control for inductively heating the metal strip in this embodiment) becomes unstable. Therefore, in this embodiment, the instruction unit 114 integrates the L1 change amount calculated in the first period (= second period) and outputs an operation based on the integrated value of the L1 change amount in the third period, which is a positive integer multiple of the first period (= second period), to the actuator 131 as an operation instruction. In this manner, the instruction unit 114 issues an operation instruction while the circuit 120 is energized (when AC power is being supplied to the load 124).

[0079] <Processing method> Next, an example of the processing method of this embodiment using the processing device 110 will be described with reference to the flowchart of Fig. 5. The flowchart of Fig. 5 is repeated in the first period (the flowchart of Fig. 5 is performed once within the time of the first period). Also, here, a case where the L1 transformation function 403 shown in Fig. 4(c) is used will be illustrated as an example.

[0080] In step S501, the acquisition unit 111 acquires the actual voltage value V measured by the voltmeter 132, the actual current value I measured by the ammeter 133, and the actual inductance value of the inductance variable device 122. The actual voltage value, actual current value, and actual inductance value acquired in step S501 are, for example, current values.

[0081] Next, in step S502, the impedance calculation unit 112 calculates the input impedance Z of the circuit 120 based on the actual voltage value V and the actual current value I acquired in the most recent step S501. in Calculate.

[0082] Next, in step S503, the variable reactance element calculation unit 113 calculates the input impedance Z in , the input impedance Z of the circuit 120 calculated in step S502 in the nth iterative process in By subtracting the input impedance Z in 5 is executed for the first time, the input impedance Z of the circuit 120 calculated in step S502 in the nth iteration is calculated. in Therefore, in this embodiment, the input impedance Z of the circuit 120 calculated in step S502 in the nth iteration of the repetitive process is in If there is no input impedance Z of the circuit 120, the process of step S503 is omitted. However, when the flowchart of FIG. 5 is executed for the first time (the input impedance Z of the circuit 120 calculated in step S502 in the nth iteration), in ), the input impedance Z of the circuit 120 in Alternatively, a predetermined value may be used.

[0083] Next, in step S504, the variable reactance element calculation unit 113 calculates the time change of the inductance actual value by subtracting the inductance actual value acquired in step S501 in the n-th previous repetition process from the inductance actual value acquired in the most recent step S501. The process of step S504 may be performed before step S502 or before step S503, as long as it is performed after step S501. When the flowchart of FIG. 5 is performed for the first time, the inductance actual value acquired in step S501 in the n-th previous repetition process does not exist. Therefore, in this embodiment, a case in which the process of step S504 is omitted when the inductance actual value acquired in step S501 in the n-th previous repetition process does not exist is illustrated. However, when the flowchart of FIG. 5 is performed for the first time (when the inductance actual value acquired in step S501 in the n-th previous repetition process does not exist), a predetermined value may be used instead of the inductance actual value of the circuit 120.

[0084] Next, in step S505, the variable reactance element calculation unit 113 calculates the input impedance Z in The slope of graph 201 is calculated by dividing the time change of the actual inductance value calculated in the most recent step S504 by the time change of the actual inductance value calculated in the most recent step S504. As described above, in this embodiment, when the flowchart in Fig. 5 is performed for the first time, the processing in steps S503 and S504 is omitted, and therefore, the processing in step S505 is not performed.

[0085] Next, in step S506, the variable reactance element calculation unit 113 calculates the L1 change amount based on the slope of the graph 201 calculated in the most recent step S505 and the L1 conversion function 403. As described above, in this embodiment, when the flowchart in FIG. 5 is performed first, the process of steps S503 to S505 is omitted. Therefore, in this embodiment, when the flowchart in FIG. 5 is performed first (when the process of steps S503 to S505 is omitted), the variable reactance element calculation unit 113 derives the L1 change amount not based on the slope of the graph 201 and the L1 conversion function 403. For example, the variable reactance element calculation unit 113 may set the L1 change amount to a predetermined value.

[0086] Next, in step S507, the instruction unit 114 updates the L1 change amount by adding the L1 change amount calculated in the most recent step S506 to the L1 change amount stored in the L1 change amount storage area. Note that in this embodiment, a case is illustrated in which the initial value of the L1 change amount stored in the L1 change amount storage area is 0 (zero). Note that the L1 change amount storage area is set in, for example, a memory or a register included in the processing device 110.

[0087] Next, in step S508, the instruction unit 114 determines whether it is time to issue an operation instruction. In this embodiment, a case is illustrated in which an operation instruction is issued in a third cycle that is a positive integer multiple of the first cycle (the repetition cycle of the flowchart in FIG. 5). For example, if the third cycle is 10 times the first cycle, the timing to issue an operation instruction arrives every time the flowchart in FIG. 5 is repeated 10 times.

[0088] 5 ends. On the other hand, if it is determined in step S508 that it is time to issue an operation instruction (YES in step S508), the process in step S509 is performed. In step S509, the instruction unit 114 issues an operation instruction to the actuator 131 based on the L1 change amount stored in the L1 change amount storage area.

[0089] Next, in step S510, the instruction unit 114 resets the L1 change amount stored in the L1 change amount storage area (sets it to 0 (zero)). When the processing of step S510 ends, the processing according to the flowchart in FIG. 5 ends. As described above, when the processing according to the flowchart in FIG. 5 ends, the processing according to the flowchart in FIG. 5 resumes. The flowchart in FIG. 5 may end, for example, based on an operation by an operator on the processing device 110, or based on a command from an external device.

[0090] <Example> Next, examples will be described, but the present invention is not limited to the examples. In a manufacturing line for metal plates where an induction heating device is installed, an RLC series resonant circuit is configured with a power supply device 121, an inductance variable device 122, a capacitor 123, and a load 124 (induction heating device and metal plate) in the same manner as in circuit 120, and the inductance L1 is changed as described in this embodiment while the metal plate is being induction heated. The results are shown in Figures 6 and 7. Figure 6 shows the input impedance Z in 6 is a graph showing an example of the relationship between the input impedance Z in Graph 602 shows the inductance L1. Graph 603 shows the input impedance Z when the above-mentioned RLC series resonant circuit is in a resonant state. in As shown in Figure 6, the input impedance Z inIt can be seen that the input impedance Z approaches a resonant state over time (see graphs 601 and 603). in 7 is a diagram showing an example of the relationship between inductance L1 and inductance L1 (in arbitrary units). The white circles shown in Fig. 7 are obtained from values ​​at the same time in graphs 601 and 602 shown in Fig. 6. Graph 701 shown in Fig. 7 corresponds to graph 201 shown in Fig. 2. As shown in Fig. 7, it can be seen that inductance L1 is concentrated near the peak (minimum value) of the irrational function represented by graph 701.

[0091] <Summary> As described above, in this embodiment, the processing device 110 detects the input impedance Z in and the actual value of inductance L1, an amount of L1 change is calculated, and an operation based on the amount of L1 change is instructed to actuator 131. Therefore, it is possible to prevent the condition for putting circuit 120 into a resonant state (searching for inductance L1 at the position showing peak 202) from being changed according to load 124. Therefore, it is possible to easily and reliably adjust the impedance of circuit 120 so that reactive power is reduced according to changes in the reactance of load 124.

[0092] In this embodiment, the processing device 110 also calculates the input impedance Z in and the actual value of inductance L1, the slope of graph 201 is calculated, and the amount of change in L1 is calculated based on the calculated slope of graph 201. Therefore, it is possible to quantitatively calculate whether inductance L1 should be increased or decreased, and by how much it should be changed.

[0093] For example, the processing device 110 can determine whether to increase or decrease the inductance L1 based on the sign of the slope of the graph 201. Also, the processing device 110 can determine the absolute value of the change amount of the inductance L1 based on the absolute value (magnitude) of the slope of the graph 201.

[0094] In this embodiment, the variable reactance element is an inductance, and the inductance variable device 122, the capacitor 123, and the load 124 are connected in series (to the power supply device 121). This makes it possible to reduce the cost of the power supply device compared to a case where the power supply frequency is included in the variable reactance element. In addition, since an RLC series resonant circuit can be configured, it is possible to prevent the calculation formula for the input impedance of the circuit from becoming complicated, and therefore it is possible to prevent the relational formula between the input impedance and the variable reactance element from becoming complicated.

[0095] <Modification> The input impedance Z of the circuit 120 in When the input impedance Z is in a resonant state, in (See graphs 601 and 603). This corresponds to an increase in the number of white circles in Fig. 7 that are located away from the peak (minimum value) of the irrational function represented by graph 701. Depending on the initial value of inductance L1, this time may be longer.

[0096] In this regard, if the inductance L1 is close to the peak (minimum) of the irrational function represented by the graph 701, then the input impedance Z in When the input impedance Z is in a resonant state, in Therefore, when at least one of the components of the load 124 is changed, the processing device 110 may determine an initial value of the inductance L1 according to the attribute of the changed component, instruct the actuator 131 to set the inductance L1 to the determined initial value, and then execute the method described in this embodiment (for example, the process according to the flowchart in FIG. 5).

[0097] In this embodiment, when the metal strip to be heated in the induction heating device is changed, the initial value of inductance L1 may be determined according to the attributes of the changed metal strip. The attributes of the metal strip may include, for example, at least one of width, thickness, and type (components of the metal strip). The relationship between the attributes of the changed component and inductance L1 may be determined, for example, by changing inductance L1 as described in this embodiment and plotting graphs 601 and 602 (input impedance Z in , inductance L1 vs. time) for various loads 124 (various metal strips in this embodiment). In this case, graph 601 (input impedance Z in ) is the input impedance Z when the RLC series resonant circuit is in a resonant state. in ) may be obtained for each of the various loads 124. Then, based on the inductance L1 obtained for each of the various loads 124, an initial value of the inductance L1 may be determined for each of the various loads 124. The graphs 601 and 602 as shown in FIG. 6 may be obtained by actually operating the circuit 120, or may be obtained by performing a circuit simulation. Note that even when the variable reactance element is not only an inductance, the initial value of the variable reactance element can be determined in advance, similarly to when the variable reactance element is only an inductance.

[0098] The above-described embodiment of the present invention can be realized by a computer executing a program. A computer-readable recording medium having the program recorded thereon and a computer program product such as the program can also be applied as an embodiment of the present invention. Examples of the recording medium that can be used include a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a non-volatile memory card, and a ROM. The embodiment of the present invention can be realized by a PLC (Programmable Logic Controller) or dedicated hardware such as an ASIC (Application Specific Integrated Circuit). Furthermore, the above-described embodiments of the present invention are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0099] <Disclosure> The disclosure of the above embodiment can be, for example, as follows. (Disclosure 1) A processing device for performing processing for adjusting an input impedance of a circuit including a power supply device and a load, An acquisition means for acquiring at least two actual values ​​of an output voltage, an output current, and an output power of the power supply device, and an actual value of a variable reactance element in the circuit; an impedance calculation means for calculating the input impedance based on the at least two actual values; a variable reactance element calculation means for calculating an amount of change in the variable reactance element based on the input impedance calculated by the impedance calculation means and an actual value of the variable reactance element; an instruction means for instructing an operation based on an amount of change in the variable reactance element to an operation terminal for changing a value of the variable reactance element while the circuit is energized; having A processing device, wherein the variable reactance element is an element that can be manipulated by the manipulated end, selected from inductance, capacitance, and frequency. (Disclosure 2) The processing device according to Disclosure 1, wherein the variable reactance element calculation means calculates an amount of change in the variable reactance element based on a slope represented by a ratio of a time change in the input impedance calculated by the impedance calculation means to a time change in the actual value of the variable reactance element. (Disclosure 3) The processing device according to disclosure 2, wherein the variable reactance element calculation means determines whether to increase or decrease the value of the variable reactance element based on a sign of the gradient. (Disclosure 4) The processing device according to Disclosure 2 or 3, wherein the variable reactance element calculation means calculates the amount of change of the variable reactance element based on the gradient and information indicating a correspondence relationship between the gradient and the amount of change of the variable reactance element. (Disclosure 5) The processing device according to Disclosure 4, wherein the correspondence relationship includes a relationship in which the greater the absolute value of the gradient, the greater the absolute value of the change amount of the variable reactance element. (Disclosure 6) The processing device according to any one of claims 1 to 5, wherein the variable reactance element is at least one of an inductance and a capacitance. (Disclosure 7) the variable reactance element is an inductance; The circuit includes an inductance variable device that adjusts an inductance in the circuit, and a capacitor having a fixed capacitance; The processing device according to Disclosure 6, wherein the variable inductance device, the capacitor, and the load are connected in series. (Disclosure 8) A processing method for adjusting an input impedance of a circuit including a power supply device and a load, comprising: an acquisition step of acquiring at least two actual values ​​of an output voltage, an output current, and an output power of the power supply device, and an actual value of a variable reactance element in the circuit; an impedance calculation step of calculating the input impedance based on the at least two actual values; a variable reactance element calculation step of calculating an amount of change in the variable reactance element based on the input impedance calculated in the impedance calculation step and an actual value of the variable reactance element; an instruction step of instructing an operation based on an amount of change in the variable reactance element to an operating terminal for changing a value of the variable reactance element while the circuit is energized; having A processing method, wherein the variable reactance element is an element that can be manipulated by the manipulated end, selected from inductance, capacitance, and frequency. (Disclosure 9) A program for causing a computer to function as each of the means of the processing device according to any one of Disclosures 1 to 7. [Explanation of symbols]

[0100] 110 Processing equipment 111 Acquisition Department 112 Impedance calculation unit 113 Variable reactance element calculation unit 114 Instruction section 120 circuits 121 Power supply 122 Variable inductance device 123 Capacitor 124 Load 131 Actuator 132 Voltmeter 133 Ammeter 201 Graph showing the relationship between input impedance and inductance 202 Peak of the graph showing the relationship between input impedance and inductance 401-403 Graph showing the relationship between the slope of the graph and the amount of L1 change 601 Graph showing input impedance vs. time 602 Graph showing the relationship between inductance and time 603 Graph showing input impedance in resonance state 701 Graph showing the relationship between input impedance and inductance

Claims

1. A processing device for performing processing for adjusting an input impedance of a circuit including a power supply device and a load, an acquisition means for acquiring at least two actual values ​​of an output voltage, an output current, and an output power of the power supply device, and an actual value of a variable reactance element in the circuit; an impedance calculation means for calculating the input impedance based on the at least two actual values; a variable reactance element calculation means for calculating an amount of change in the variable reactance element based on the input impedance calculated by the impedance calculation means and an actual value of the variable reactance element; an instruction means for instructing an operation based on an amount of change in the variable reactance element to an operation terminal for changing a value of the variable reactance element while the circuit is energized; having A processing device, wherein the variable reactance element is an element that can be manipulated by the manipulated end, selected from inductance, capacitance, and frequency.

2. 2. The processing device according to claim 1, wherein the variable reactance element calculation means calculates an amount of change in the variable reactance element based on a slope represented by a ratio of a time change in the input impedance calculated by the impedance calculation means to a time change in the actual value of the variable reactance element.

3. 3. The processing device according to claim 2, wherein the variable reactance element calculation means determines whether to increase or decrease the value of the variable reactance element based on a sign of the gradient.

4. 4. The processing device according to claim 2, wherein the variable reactance element calculation means calculates the amount of change in the variable reactance element based on the gradient and information indicating a correspondence relationship between the gradient and the amount of change in the variable reactance element.

5. The processing device according to claim 4 , wherein the correspondence relationship includes a relationship in which the greater the absolute value of the gradient, the greater the absolute value of the change amount of the variable reactance element.

6. 4. The processing device according to claim 1, wherein the variable reactance element is at least one of an inductance and a capacitance.

7. the variable reactance element is an inductance; The circuit includes an inductance variable device that adjusts an inductance in the circuit, and a capacitor having a fixed capacitance; The processing device according to claim 6 , wherein the variable inductance device, the capacitor, and the load are connected in series.

8. A processing method for adjusting an input impedance of a circuit including a power supply device and a load, comprising: an acquisition step of acquiring at least two actual values ​​of an output voltage, an output current, and an output power of the power supply device, and an actual value of a variable reactance element in the circuit; an impedance calculation step of calculating the input impedance based on the at least two actual values; a variable reactance element calculation step of calculating an amount of change in the variable reactance element based on the input impedance calculated in the impedance calculation step and an actual value of the variable reactance element; an instruction step of instructing an operation based on an amount of change in the variable reactance element to an operating terminal for changing a value of the variable reactance element while the circuit is energized; having A processing method, wherein the variable reactance element is an element that can be manipulated by the manipulated end, selected from inductance, capacitance, and frequency.

9. A program for causing a computer to function as each of the means of the processing device according to any one of claims 1 to 3.

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