Power Converter

Abstract

To provide a power converter capable of matching the magnitude and phase of output of each resonance type power supply as much as possible with a feedback circuit that is as simple as possible.SOLUTION: Each of error amplifiers 52, ..., 5n determines the difference of magnitudes between a detected input current value into respective resonance type power supplies 21, ..., 2n by respective current sensors 42, ..., 4n and a reference current value. Each of phase adjustment circuits 62, ..., 6n adjusts the switching phase of respective switching elements M2, ..., Mn of respective resonance type power supplies 22, ..., 2n in response to the output of respective error amplifies 52, ..., 5n. Each of the phase adjustment circuits 62, ..., 6n controls so that, if the detected current value is larger than the reference current value, it delays the switching phase of respective resonance type power supplies 22, ..., 2n, on the contrary, if the detected current value is smaller, it advances the switching phase of respective resonance type power supplies 22, ..., 2n, and, when the reference current value and the detected input current value coincide together, it fixes the phase.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power converter. [Background technology]

[0002] Conventionally, RF (Radio Frequency) power amplifiers have been developed that can obtain large power by connecting multiple resonant power sources in parallel. RF power amplifiers are used in various applications such as induction heating, plasma processes, and wireless power supply. In these applications, RF power amplifiers are required to be small and highly efficient in terms of ease of integration and power utilization rate, and high output is required to achieve higher processing capabilities and power supply.

[0003] For example, a class E resonant power supply using a semiconductor switch is suitable for making RF power amplifiers smaller and more efficient. In principle, the output power of a class E resonant power supply can be increased by increasing the DC input voltage, but a voltage 3.56 times the input voltage is applied to the semiconductor switch. For this reason, it is limited by the withstand voltage of the semiconductor switch.

[0004] By combining the power of multiple class E resonant power supplies using a power combining circuit, it is possible to achieve an output that exceeds the output limit set by the voltage resistance of the semiconductor switch. However, since a separate power combining circuit is required, this can cause a decrease in power conversion efficiency. There are also research examples in which the output of class E resonant power supplies is directly combined without a separate power combining circuit.

[0005] In this research example, in order to achieve high output power, it is necessary to match the output magnitude and phase of each class E resonant power supply. Even if each class E resonant power supply has the same configuration, it is difficult to match the output magnitude and phase of each resonant power supply because there is variation in the elements within each class E resonant power supply. Output imbalance increases the loss of the semiconductor switching elements within a specific class E resonant power supply, preventing it from achieving high output power.

[0006] For these reasons, the technology described in Patent Document 1 proposes a configuration in which a phase-control matching circuit equipped with a π-connected variable capacitor or variable inductor is added and a resonant power supply is connected in parallel. In this configuration, the input current, output current, and output voltage to the resonant power supply are detected, and an automatic matching control circuit controls the phase-control matching circuit based on the results, thereby matching the magnitude and phase of the output of the resonant power supply.

[0007] However, the phase-control matching circuit described in Patent Document 1 uses a variable capacitor and a variable inductor, which leads to an increase in the size of the circuit and the size of the resonant power supply. In addition, the specific configuration of the automatic matching control circuit and the specific method of controlling the detection value are not described.

[0008] In the configuration shown in Figure 3 of Patent Document 2, a phase difference control circuit is added. This is used to control the high frequency pulse drive circuit, and the phase difference between the switching elements of the parallel-connected resonant power supply can be controlled to match the magnitude and phase of the output of the power supply circuit. Since this configuration controls the phase difference between the switching elements, no large additional parts are required. However, even in the technology described in Patent Document 2, the specific configuration of the phase difference control circuit and the specific method of phase control are not described. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5832702 (Figure 1) [Patent Document 2] Patent No. 6305438 (Figure 3) Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in consideration of the above, and an object of the present invention is to provide a power converter that can match the magnitude and phase of the outputs of each resonant power supply as closely as possible using a feedback circuit that is as simple as possible. [Means for solving the problem]

[0011] According to the invention of claim 1, two or more systems of class E resonant power supplies are provided, each of which outputs AC using a switching element and has outputs connected in parallel. A current detection unit detects the current of each resonant power supply. A judgment unit judges whether a current detection value of the resonant power supply by the current detection unit is larger than a reference current value. A phase adjustment circuit adjusts the switching phase of the switching element of each resonant power supply according to the judgment result of the judgment unit, and controls the input currents to match by leading or lagging the switching phase.

[0012] The phase adjustment circuit delays the switching phase of the resonant power supply if the current detection value by the current detection unit is greater than the reference current value, and advances the switching phase of the resonant power supply if the current detection value is smaller, and controls the phase to be fixed when the reference current value and the current detection value match. This allows the circuit to be configured using as simple a feedback circuit as possible, and makes it possible to match the magnitude and phase of the output of each resonant power supply as much as possible. Here, it is desirable that the reference current value is determined in advance to a predetermined value, or is determined based on the current detection value of the resonant power supplies connected in parallel. [Brief description of the drawings]

[0013] [Figure 1] Electrical configuration diagram of a power converter in the first embodiment [Diagram 2] Electrical diagram of the phase adjustment circuit [Diagram 3] Simulation result diagram 1 [Figure 4] Simulation result diagram 2 [Diagram 5] Experimental result diagram 1 [Figure 6] Experimental result diagram 2 [Figure 7] Electrical configuration diagram of a resonant power supply in the second embodiment [Figure 8] Electrical configuration diagram of a resonant power supply in the third embodiment [Figure 9] A diagram showing the optimum operating waveforms of a class E amplifier [Figure 10] Electrical configuration diagram of a power converter in a fourth embodiment [Figure 11] Electrical configuration example used for PI control in the fifth embodiment [Figure 12] Simulation results comparing I control and PI control [Figure 13] Electrical configuration diagram when two resonant power supplies are combined in the sixth embodiment [Figure 14] Illustrative diagram of limit conditions for suppressing imbalance through phase control [Figure 15] FIG. 13 is an electrical configuration diagram when a phase adjustment circuit is configured in multiple stages in the seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, several embodiments of the power converter will be described with reference to the drawings. Note that components that are substantially common to the embodiments will be described by using the same or similar reference numerals, for example, the same reference numerals in the tens and ones digits.

[0015] (First embodiment) A first embodiment of the power converter 10 will be described below with reference to Figs. 1 to 6. The power converter 10 is configured with two or more systems of class E resonant power supplies 21, 22, ..., 2n. The resonant power supplies 21, 22, ..., 2n are connected in parallel and have their outputs commonly connected. The resonant power supplies 21, 22, ..., 2n each include switching elements M1, M2, ..., M n In the following explanation, components of the kth system (where k=1 . . . n) of the resonant power supply 2 are assigned a number corresponding to the subscript k.

[0016] Each of the resonant power supplies 21, 22, ..., 2n is divided into a master resonant power supply 21 that outputs a reference current value, and a slave resonant power supply 22, ..., 2n that operates while inputting and correcting the reference current value. The resonant power supply 21 includes a switching element M1. The resonant power supply 21 also includes a choke inductor L f1 , resonance capacitor C r1 , and the resonant inductor L r1 are connected in series, and the drain-source of the switching element M1 and the shunt capacitor C1 are connected to the choke inductor L f1 and the resonant inductor L r1 and a ground. A square wave is input to the gate of the switching element M1 from a square wave oscillator 30 via a driver 111. A current sensor 41 is provided at the input of the resonant power supply 21.

[0017] The input of each of the resonant power supplies 21, 22, ..., 2n is supplied with power from a DC power supply 100. The outputs of each of the resonant power supplies 21, 22, ..., 2n are commonly connected, and a load resistance R L are connected to each of the resonant power supplies 21, 22, ..., 2n. Current sensors 41, 42, ..., 4n that detect the input current from the DC power supply 100 are provided as input current detection units in each of the resonant power supplies 21, 22, ..., 2n. The current sensor 41 that detects the input current to the resonant power supply 21 uses the input current detection value as a reference current value, and outputs the reference current value to the resonant power supplies 22, ..., 2n.

[0018] The slave side resonant power supplies 22, ..., 2n are respectively provided with switching elements M2, ..., M n The resonant power supplies 22, ..., 2n also include a choke inductor L f2 , … , L fn , resonance capacitor C r2 , … , C rn , and the resonant inductor L r2 , … , L rn are connected in series, while switching elements M2, ..., M n Drain-source and shunt capacitors C2, ..., C n The choke inductor Lf2 , … , L fn and the resonant inductor L r2 , … , L rn and the ground. Also, the switching elements M2, ..., M n A square wave is input to the gates of the gates from the square wave oscillator 30 through phase adjustment circuits 62, . . . , 6n and drivers 112, .

[0019] Moreover, the resonant power supplies 22, ..., 2n on the slave side each have a current sensor 42, ..., 4n at its input. Moreover, the resonant power supplies 22, ..., 2n each have an error amplifier 52, ..., 5n and a phase adjustment circuit 62, ..., 6n. The error amplifiers 52, ..., 5n are circuits that function as judgment units that, when a reference current value is input, judge whether the input current detection value by the current sensor 42, ..., 4n of the resonant power supplies 22, ..., 2n itself is larger than the reference current value. The error amplifiers 52, ..., 5n output the judgment result to the phase adjustment circuits 62, ..., 6n.

[0020] The internal components of the slave side resonant power supplies 22, ..., 2n are all the same. Therefore, the internal configuration of the resonant power supply 22 will be described, and descriptions of the internal components of the other slave side resonant power supplies 23, ..., 2n will be omitted. The resonant power supply 22 is configured with an error amplifier 52. As shown in FIG. 2, the error amplifier 52 has a resistor R m , R p and a capacitor C connected between the output and inverting input terminal of the op-amp OP. f The error amplifier 52 is configured by an integrator having a resistor R m The inverting input terminal is connected via resistor R p The reference current value is input to the non-inverting input terminal via the amplifier 62, and the difference between these currents is amplified and output to the phase adjustment circuit 62.

[0021] The current sensor 42 is configured using a magnetic field detection type current sensor. For example, the current sensor 42 is configured by combining a magnetic core arranged to surround the current path and having a slit in one part, and a Hall element arranged in the slit, and detects the current by detecting the magnetic field with the Hall element. By using this current sensor 42, it is possible to prevent power loss. The current sensor 42 may also be configured by installing a Hall IC in the current path flowing through the board. By using such a current sensor 42, the implementation is simplified and it becomes easier to handle.

[0022] The phase adjustment circuit 62 of the resonant power supply 22 adjusts the phase of the drive voltage for driving the switching element M2 (hereinafter referred to as the switching phase) in accordance with the determination result by the error amplifier 52. If the input current detection value is greater than the reference current value, the phase adjustment circuit 62 delays the switching phase for driving the switching element M2 of the resonant power supply 22. If the input current detection value is smaller than the reference current value, the phase adjustment circuit 62 advances the switching phase for driving the switching element M2 of the resonant power supply 22. The phase adjustment circuit 62 controls so that the switching phase is fixed when the reference current value and the input current detection value match.

[0023] 2, the phase adjustment circuit 62 is configured using an integrator 72, a resistor voltage divider circuit 82 configured by connecting resistors Ra and Rb in series, a D flip-flop 92, and other peripheral circuits. The integrator 72 receives the square wave output by the square wave oscillator 30, and delays the phase of the voltage according to a predetermined time constant to dull the voltage waveform, and then outputs a bypass capacitor C b The signal is input to the clock terminal of a D flip-flop 92 through the D flip-flop 92. The D flip-flop 92 is configured by pulling up the D terminal and connecting a resistive voltage divider circuit 82 to the clock terminal. A peripheral circuit 102 is connected to the / Q terminal and / CLR terminal of the D flip-flop 92.

[0024] The output of error amplifier 52 is applied to the input of resistive voltage divider circuit 82. That is, a voltage according to the output of error amplifier 52 is superimposed on the output voltage of integrator 72 and input to the clock terminal. As a result, a voltage obtained by adding or subtracting a voltage that changes according to the output voltage of error amplifier 52 is input to the clock terminal of D flip-flop 92.

[0025] The clock terminal of the D flip-flop 92 receives a rising pulse when the voltage exceeds a predetermined voltage level and receives a falling pulse when the voltage falls below the predetermined voltage level. Therefore, a square wave whose phase is shifted by an amount corresponding to the output voltage of the error amplifier 52 is input to the clock terminal of the D flip-flop 92. The D flip-flop 92 outputs a square wave voltage from the Q terminal in synchronization with the input voltage of the clock terminal, and can output a shaped voltage whose phase is shifted according to the output of the error amplifier 52. As a result, the phase adjustment circuit 62 outputs a result whose phase has been adjusted based on the integration result by the integrator 72.

[0026] This shaping voltage is input to the gate terminal of the switching element M2. Therefore, it is possible to change the phase of the square wave applied to the gate terminal of the switching element M2 of the slave-side resonant power supply 22 with respect to the phase of the square wave applied to the gate terminal of the switching element M1 that drives the master-side resonant power supply 21.

[0027] <Simulation results> The inventors have proposed a resonant inductor L r1 , … L rn The simulation was performed with a normal distribution variation equivalent to 3σ, where σ is the standard deviation of the element value variation. The number n of parallel resonant power supplies 22, ..., 2n was set to 4, and the number of trials was 300. The results are shown in Figures 3 to 6.

[0028] 3 and 4, the drain loss difference on the vertical axis and the worst value of the drain loss on the horizontal axis are both shown on the same scale for comparison. In the case where there is no phase adjustment, when the element values ​​vary, as shown in FIG. n It was confirmed that the drain loss difference between the switching elements M1, ..., M2, and the worst value of the drain loss also varies. By using the phase adjustment circuits 62, ..., 6n of this embodiment, as shown in FIG. 4, it is possible to reduce the drain loss, i.e., the switching element loss difference, and also to reduce the drain loss between the switching elements M1, ..., M2, and the worst value of the drain loss. n It was also confirmed that the worst-case loss value could be reduced.

[0029] FIG. 5 shows the relationship between the output power of the switching elements M1, ..., M n The experimental results of the drain loss of the switching elements M1, ..., M n 5 and 6 show the drain loss of the switching elements M1, ..., M2, even if the output power is increased, the drain loss of the switching elements M1, ..., M2 is increased. n It was confirmed that the increase in loss in each of the resonant power supplies 21, ..., 2n could be suppressed. In addition, the output of each of the resonant power supplies 21, ..., 2n could be leveled, and the deterioration due to the loss in each of the resonant power supplies 21, ..., 2n could be leveled.

[0030] The effects of this embodiment will be described below. If the input current detection value is greater than the reference current value, the phase adjustment circuits 62, ..., 6n delay the switching phase of the slave resonant power supplies 22, ..., 2n. If the input current detection value is smaller than the reference current value, the phase adjustment circuits 62, ..., 6n advance the switching phase of the resonant power supplies 22, ..., 2n. Then, the phase adjustment circuits 62, ..., 6n perform control so as to fix the phase when the reference current value and the input current detection value match. Even if the resonant inductor L r1 , … , L rnEven if there is a large variation in inductance, it is possible to make the magnitude and phase of the output of each of the resonant power sources 21, . . . , 2n match as closely as possible using a feedback circuit that is as simple as possible.

[0031] Furthermore, the phase adjustment circuits 62, ..., 6n can be constructed using small components, and the magnitude and phase of the outputs of the resonant power supplies 21, ..., 2n can be matched as much as possible. The error amplifiers 52, ..., 5n do not require rectification because their detection signals are DC, making processing easy. This allows the error amplifiers 52, ..., 5n and the phase adjustment circuits 62, ..., 6n to be constructed simply. This can be achieved by simple control in which the switching phase is feedback-controlled according to the magnitude of the input current detection value of the current sensors 41, ..., 4n and the reference current value. Moreover, there is no need to limit the composite number of the resonant power supplies 21, ..., 2n.

[0032] In addition, the effect can be achieved by simply adding small parts such as the current sensors 41, ..., 4n, the error amplifiers 52, ..., 5n, and the phase adjustment circuits 62, ..., 6n. Furthermore, even if there is variation in the passive elements in the individual resonant power supplies 21, ..., 2n, the power can be combined with the magnitude and phase of the output of each resonant power supply 21, ..., 2n being matched, and the switching elements M1, ..., M n This can suppress the increase in loss.

[0033] Second embodiment The second embodiment will be described with reference to Fig. 7. A push-pull configuration may be used for each of the resonant power supplies 21, ..., 2n. Fig. 7 shows the electrical configuration of one system of resonant power supply 221, but the configuration of this resonant power supply 221 may be applied to the configurations of all of the resonant power supplies 21, ..., 2n, and these configurations may be connected in parallel.

[0034] The resonant power supply 221 includes a choke inductor L f1a , L f1b , resonant inductor L r1a , L r1b , resonance capacitor C r1a、 C r1bThe choke inductor L of each series-connected circuit is connected in parallel. f1a , L f1b , resonant inductor L r1a , L r1b A switching element M is connected between each intermediate node of the 1a、 M 1b and capacitor C 1a、 C 1b At this time, the square wave oscillator 30 drives the switching element M through the drivers 111a and 111b. 1a、 M 1b A push-pull configuration is achieved by applying a rectangular wave pulse in a complementary manner and in opposite phase to the gates of the resonant power supply 221. By adopting such a push-pull configuration, it is possible to reduce the imbalance that is likely to occur in the resonant power supply 221.

[0035] Third embodiment The third embodiment will be described with reference to Fig. 8. As in the second embodiment, the resonant power supplies 21, ..., 2n may be configured in parallel as shown in Fig. 8. As in the second embodiment, Fig. 8 shows the configuration of one system of resonant power supply 321, but the configuration of this resonant power supply 321 may be applied to the configurations of all of the resonant power supplies 21, ..., 2n.

[0036] As shown in FIG. 8, a resonant power supply 321 includes a choke inductor L f1a , L f1b , switching element M 1a , M 1b , and a capacitor C 1a , C 1b In addition, a common resonant inductor L r1 , resonance capacitor C r1 In this case, the square wave oscillator 30 may be configured to directly connect the pair of switching elements M through the drivers 111a and 111b. 1a , M 1b It is preferable to apply the same pulse of a square wave to the gates of the transistors 1 and 2. By adopting such a parallel configuration, the imbalance can be reduced.

[0037] (Fourth embodiment) The fourth embodiment will be described with reference to Figures 9 and 10. For example, since the input current Idc input to the resonant power supply 21 of the first embodiment is passed through the switching element M1, there is a certain relationship between the input current Idc and the current is flowing through the switching element M1.

[0038] For example, in a power converter operating in class E, as shown in FIG. n When the on-duty ratio of the switching element M1 is D, the current is of the switching element M1 is Idc-I0sin(ωt+φ) when 0<ωt≦πD, and is 0 when πD≦ωt≦2πD.

[0039] For this reason, as shown in the power converter 410 of FIG. s1 …M sn The drain and gate terminals of the switching elements M1...M n and a current sense element M s1 …M sn The source of the switching element M1...M n By connecting the source of each switching element M1...M n The current is flowing through the current sensing element M may be obtained by a detection resistor. s1 …M sn By inputting the detection value of the detection resistor to the error amplifier 52...5n, the current sensor 42...4n is not used and the current sense element M s1 …M sn The imbalance suppression control may be performed based on the detected value of the current sensor 42...4n. This makes it possible to reduce the number of current sensors 42...4n, thereby making the device more compact.

[0040] Fifth embodiment The fifth embodiment will be described with reference to Fig. 11 and Fig. 12. As shown in Fig. 11, an error amplifier 552, which replaces the error amplifier 52, includes a capacitor C f A feedback resistor R in series withf This makes it possible to execute PI control. Fig. 12 shows a comparison of simulation results of transient phenomenon characteristics, plotting output voltage versus time when I control is executed and when PI control is executed. It has been confirmed that by executing PI control compared to when I control is executed, the time required to control the output voltage to a constant level within a certain range can be improved by the time difference Δt.

[0041] Sixth embodiment The sixth embodiment will be described with reference to Fig. 13 and Fig. 14. In the above-described embodiments, a configuration in which n resonant power supplies 21, ..., 2n are combined is described, but in this embodiment, a configuration in which two systems of resonant power supplies 21, 22 are combined, as shown in a power converter 610 in Fig. 13, is described.

[0042] FIG. 14 shows a resonant inductor L r1 The inductance of the resonant inductor L r2 Inductance, resonant capacitor C r2 3 illustrates the results of a simulation of the drain losses occurring in the switching elements M1 and M2 of the resonant power sources 21 and 22 when the capacitance φ is fixed.

[0043] 14, it can be seen that when the drain loss characteristics of both resonant power supplies 21, 22 deviate from a specified range from the design value of the inductance, the drain loss rises sharply and the drain loss in resonant power supplies 21, 22 becomes easily unbalanced. Conversely, this shows that if the drain-to-source voltage amplitudes of switching elements M1, M2 of the two resonant power supplies 21, 22 are easily matched, the unbalance can be dramatically suppressed, and that when the unbalance in the voltage amplitudes increases, the drain loss rises sharply, resulting in unbalance.

[0044] The theoretical boundary condition for the imbalance limit that can be suppressed by phase control is sin(θ2-θ1)=(Xr2 -X r1 ) / (2 R L ) where X r1 =ωL r1 -1 / ωC r1 , X r2 =ωL r2 -1 / ωC r2 where θ1 and θ2 indicate the phase difference of the square wave voltage applied to the switching elements M1 and M2 with respect to the reference value. If this condition is changed to a condition between element values, then 2R L >|X r2 -X r1 By satisfying this condition, the imbalance can be suppressed.

[0045] Seventh embodiment The seventh embodiment will be described with reference to Fig. 15. As shown in Fig. 15, a phase adjustment circuit 62 that receives the output of an error amplifier 52 and adjusts the phase may be configured in a 2-stage cascade configuration, for example. The 2-stage configuration is not limited to a 2-stage configuration, and a 3-stage or more cascade configuration may also be used. By using a multi-stage configuration, it is possible to increase the adjustment range of the circuit.

[0046] (Other embodiments) The present invention is not limited to the above-described embodiment, and can be implemented in various modifications and variations without departing from the spirit and scope of the present invention. For example, the following modifications or extensions are possible.

[0047] In the above embodiment, the reference current value is set based on the input current detection value of one of the resonant power supplies 21 connected in parallel, but this is not limited to this. The reference current value may be set to a predetermined value in advance, or the reference current value may be set to the average value of the input current detection values ​​of all the resonant power supplies 21, 22, ..., 2n connected in parallel. It is desirable that the reference current value be set to a predetermined value in advance, or based on the current detection values ​​of the resonant power supplies connected in parallel. The type of flip-flop is not limited to the D flip-flop. Although the resonant power supplies 21, 22, . . . , 2n are configured to operate in class E, a current source type resonant power supply such as class E, class Φ, class F, etc. may also be used.

[0048] Although the present invention has been described based on the above-mentioned embodiment, it is understood that the present invention is not limited to the embodiment or structure. The present invention also includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, and other combinations and forms including one, more, or less than one element, are also within the scope and concept of the present invention. [Explanation of symbols]

[0049] In the drawing, 10, 410, 610 indicate power converters, 21, ..., 2n indicate resonant power supplies, 41, ..., 4n indicate current sensors (current detection units, input current detection units), 52, ..., 5n indicate error amplifiers (judgment units), 62, ..., 6n indicate phase adjustment circuits, 72 indicates an integrator, 82 indicates a resistive voltage divider circuit, and 92 indicates a D flip-flop (flip-flop).

Claims

1. Two or more systems are provided, each of which is a switching element (M １ , …, M ｎ ), and a resonant power supply (21, ..., 2n) that outputs AC using the A current detection unit (41, ..., 4n) for detecting a current flowing through each resonant power supply; a determination unit (52, . . . , 5n) for determining whether a current detection value detected by the current detection unit is larger than a reference current value; a phase adjustment circuit (62, ..., 6n) that adjusts a switching phase of the switching element of each resonant power supply in accordance with a determination result of the determination unit, and controls the switching phase to be advanced or delayed so as to match the current detection value with the reference current value, the phase adjustment circuit is configured to control so that if the current detection value by the current detection unit is greater than the reference current value, the phase adjustment circuit delays the switching phase of the resonant power supply, and conversely, if the current detection value is smaller than the reference current value, the phase adjustment circuit advances the switching phase of the resonant power supply, and fixes the phase when the reference current value and the current detection value match; A power converter in which the reference current value is determined in advance to a predetermined value, or is determined based on the current detection value of the resonant power supply connected in parallel.

2. 2. The power converter according to claim 1, wherein the reference current value is set based on the current detection value of one predetermined resonant power source (21) among the parallel-connected power sources.

3. 2. The power converter according to claim 1, wherein the reference current value is set to a predetermined value.

4. 2. The power converter according to claim 1, wherein the reference current value is set to an average value of the current detection values ​​of all the resonant power supplies (21, . . . , 2n) connected in parallel.

5. The resonant power supply is provided for two systems, and a resonant capacitor (C ｒ１ , C ｒ２ ) and a resonant inductor (L ｒ１ , L ｒ２ ) are connected in series, and the outputs of the two systems are combined to generate a load resistance (R Ｌ ) The variation associated with the resonant capacitor and the resonant inductor constituting the resonant power supply and the load resistance is 2R Ｌ >|X ｒ２ -X ｒ１ |, where X ｒ１ =ωL ｒ１ −1 / ωC ｒ１ , X ｒ２ =ωL ｒ２ −1 / ωC ｒ２ The power converter according to claim 1 , wherein the power converter is configured to satisfy the following relationship:

6. The power converter according to claim 1 , wherein the current detection unit detects a direct current of an input current input to each resonant power supply.

7. The power converter according to claim 1 , wherein the current detection unit detects a current passing through the switching element formed in the resonant power supply.

8. The resonant power supplies are each provided with the current detection unit, an integrator (72) that integrates the current detection value by the current detection unit; The power converter according to claim 1 , wherein the phase adjustment circuit adjusts the phase based on a result of integration by the integrator.

9. The present invention is configured using an error amplifier (52, ..., 5n) that performs PI control based on a difference between the current detection value and the reference current value, 9. The power converter according to claim 8, wherein the phase adjustment circuit performs phase adjustment using the error amplifier.

10. the determination unit is configured using an error amplifier (52, ..., 5n) that outputs a difference between the current detection value and the reference current value, 10. The power converter according to claim 1, wherein the phase adjustment circuit comprises: an integrator (72) that receives a rectangular wave voltage of a rectangular wave oscillator and delays the phase of the voltage according to a predetermined time constant to dull the voltage waveform; a resistive voltage divider circuit (82) that receives an output of the error amplifier; and a flip-flop (92) that superimposes and inputs an output of the resistive voltage divider circuit and an output of the integrator to a clock terminal, and the flip-flop outputs the rectangular wave voltage in synchronization with an input voltage to the clock terminal.

11. The power converter according to claim 1 , wherein the phase adjustment circuit has a multi-stage configuration.

12. 12. The power converter according to any one of claims 1 to 11, wherein the resonant power supply is a class E resonant power supply.

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