DAB Converter

Abstract

The present invention provides a DAB converter capable of suppressing a decrease in power transmission efficiency due to individual differences in inductance. A DAB converter comprising: a transformer having a primary winding and a secondary winding; a first full-bridge circuit; a second full-bridge circuit; a first capacitor; a second capacitor; and a control unit, wherein the primary winding is connected between an eleventh midpoint and a twelfth midpoint of the first full-bridge circuit, the secondary winding is connected between a twenty-first midpoint and a twenty-second midpoint of the second full-bridge circuit, the first capacitor is connected between two input / output terminals of the first full-bridge circuit, and the second capacitor is connected between two input / output terminals of the second full-bridge circuit, and the control unit adjusts a phase difference between a switch of the first full-bridge circuit and a switch of the second full-bridge circuit based on an estimated value of the inductance of the DAB converter.

Description

Technical Field

[0001] The present invention relates to a DAB (Dual Active Bridge) converter. Background Art

[0002] We are conducting research and development on a bidirectional isolation type converter, namely a DAB converter, which is equipped with a transformer and two full-bridge circuits.

[0003] In this regard, a DAB converter is known, which includes a transformer having a primary winding and a secondary winding, and two full-bridge circuits, and controls the switches of each of the two full-bridge circuits to suppress the reduction in the efficiency of power transmission from the primary winding to the secondary winding (see Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-251998 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Here, the DAB converter described in Patent Document 1 has a composite inductance including the inductance of the first portion of the primary winding and the inductance of the second portion of the secondary winding as the inductance of the DAB converter. However, the individual differences in the inductance of the DAB converter are large, and it is not uncommon to have an inductance different from the designed value. As a result, it is sometimes difficult for the DAB converter to suppress the reduction in the efficiency of power transmission from the primary winding to the secondary winding.

[0009] The present invention has been developed in view of such circumstances, and a technical object of the present invention is to provide a DAB converter capable of suppressing a decrease in power transmission efficiency due to individual differences in inductance.

[0010] Technical solutions to solve problems

[0011] One embodiment of the present invention provides a DAB converter, wherein the DAB (Dual Active Bridge) converter includes: a transformer having a primary winding and a secondary winding; a first full-bridge circuit; a second full-bridge circuit; a first capacitor; a second capacitor; and a control unit that controls switches of the first full-bridge circuit and switches of the second full-bridge circuit, wherein the primary winding is connected between an eleventh midpoint of two midpoints of the first full-bridge circuit and a twelfth midpoint of two midpoints of the first full-bridge circuit, the secondary winding is connected between a twenty-first midpoint of two midpoints of the second full-bridge circuit and a twenty-second midpoint of two midpoints of the second full-bridge circuit, the first capacitor is connected between two input / output terminals of the first full-bridge circuit, and the second capacitor is connected between two input / output terminals of the second full-bridge circuit, and the control unit adjusts a phase difference between switches of the first full-bridge circuit and switches of the second full-bridge circuit based on an estimated value of inductance of the DAB converter.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to suppress a decrease in power transmission efficiency due to individual differences in inductance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram showing an example of the circuit configuration of the DAB converter 1 according to the embodiment.

[0015] Figure 2 1 is a diagram showing an example of the phase difference after adjustment by the control unit 11 when the estimated value is larger than the designed value.

[0016] Figure 3 1 is a diagram showing an example of the phase difference after adjustment by the control unit 11 when the estimated value is smaller than the designed value.

[0017] Figure 4 1 is a diagram showing an example of the configuration of a DAB converter 1 in which a second current detection unit DC2 is provided instead of the first current detection unit DC1 .

[0018] Figure 5 1 is a diagram showing an example of a flow of a process in which the control unit 11 adjusts the phase difference.

[0019] Figure 6 It is a diagram showing an example of the configuration of a DAB converter 1 according to a modification of the embodiment.

[0020] Figure 7 yes Figure 6The DAB converter 1 shown is an equivalent circuit of a portion including a first portion PT1 and a second portion PT2.

[0021] Figure 8 This is a diagram for explaining processing performed by the control unit 11 when estimating an estimated value in a modification of the embodiment.

[0022] Fig. 9 This is an equivalent circuit of a portion of the DAB converter 1 including the first portion PT1 and the second portion PT2 when the secondary-side circuit is short-circuited.

[0023] Explanation of symbols

[0024] 1...DAB converter, 11...control unit, A11, A21...upper arms, A12, A22...lower arms, B1...first full-bridge circuit, B2...second full-bridge circuit, C1...first capacitor, C2...second capacitor, DC1...first current detection unit, DC2...second current detection unit, DC3...third current detection unit, DC4...fourth current detection unit, DV1...first voltage detection unit, DV2...second voltage detection unit, DV3...third voltage detection unit, DV4...fourth voltage detection unit, L1 ...first inductor, L2...second inductor, LD...load, P1...first part, P11, P12, P21, P22...midpoint, P13, P14, P23, P24, TI, TI1, TI2, TO, TO1, TO2...input and output terminals, PT1...first part, PT2...second part, S1, S2, S11, S12, S13, S14, S21, S22, S23, S24...switching element, T...transformer, T1...primary winding, T2...secondary winding DETAILED DESCRIPTION

[0025] <Implementation Method>

[0026] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. Here, in the embodiments, a conductor that transmits an electric signal corresponding to direct current power or an electric signal corresponding to alternating current power is referred to as a transmission path and will be described. The transmission path can be, for example, a conductor printed on a substrate, a wire in which the conductor is formed in a line shape, or other conductors. In addition, in the embodiments, when referring to voltage, it means the potential difference from a potential that becomes a specified reference, and the illustration and description of the reference potential are omitted. Here, the reference potential can also be any potential. In the embodiments, as an example, the case where the reference potential is the ground potential will be described. In addition, in the embodiments, for ease of explanation, the state in which current flows between the drain terminal and the source terminal in the state of a certain field effect transistor is referred to as the on state and will be described. In addition, in the embodiments, for ease of explanation, the state in which no current flows between the drain terminal and the source terminal in the state of a certain field effect transistor is referred to as the off state and will be described.

[0027] <Overview of DAB Converter>

[0028] First, an overview of the DAB converter according to the embodiment will be described. The DAB converter includes: a transformer having a primary side winding and a secondary side winding; a first full-bridge circuit; a second full-bridge circuit; a first capacitor; a second capacitor; and a control unit. Here, the primary side winding is connected between the eleventh midpoint among the two midpoints of the first full-bridge circuit and the twelfth midpoint among the two midpoints of the first full-bridge circuit. In addition, the secondary side winding is connected between the twenty-first midpoint among the two midpoints of the second full-bridge circuit and the twenty-second midpoint among the two midpoints of the second full-bridge circuit. In addition, the first capacitor is connected between the two input / output terminals of the first full-bridge circuit. In addition, the second capacitor is connected between the two input / output terminals of the second full-bridge circuit. And, the control unit controls the switches of the first full-bridge circuit and the switches of the second full-bridge circuit. Specifically, the control unit adjusts the phase difference between the switches of the first full-bridge circuit and the switches of the second full-bridge circuit based on the estimated value of the inductance of the DAB converter.

[0029] Thus, the DAB converter according to the embodiment can suppress the reduction of the power transmission efficiency due to the individual differences of the inductance. In the following, the circuit structure of this DAB converter and the operation of this DAB converter will be described in detail.

[0030] <Circuit Structure of DAB Converter>

[0031] In the following, with reference to Figure 1 , the circuit structure of the DAB converter 1 according to the embodiment will be described. Figure 1It is a diagram showing an example of the circuit configuration of the DAB converter 1 according to the embodiment.

[0032] The DAB converter 1 is an example of the above-mentioned DAB converter. The DAB converter 1 is a bidirectional insulating type converter.

[0033] The DAB converter 1 includes a transformer T, a first full-bridge circuit B1, a first inductor L1, a first capacitor C1, a second full-bridge circuit B2, a second inductor L2, a second capacitor C2, two input / output terminals TI, two input / output terminals TO, and a control unit 11. Figure 1 In the example shown, the DAB converter 1 is connected to the information processing device 2. In addition, the DAB converter 1 may also be a structure that does not include at least one of the first inductor L1 and the second inductor L2. In addition, hereinafter, for the convenience of explanation, one of the two input-output terminals TI is referred to as input-output terminal TI1, and the other of the two input-output terminals TI is referred to as input-output terminal TI2. In addition, hereinafter, for the convenience of explanation, one of the two input-output terminals TO is referred to as input-output terminal TO1, and the other of the two input-output terminals TO is referred to as input-output terminal TO2. In addition, Figure 1 In order to prevent the figure from becoming complicated, a transmission path connecting the control unit 11 and other circuits in the DAB converter 1 is not depicted.

[0034] Here, as described above, the DAB converter 1 is a bidirectional insulating converter. Therefore, the two input-output terminals TI function as input terminals of the DAB converter 1 when a DC power supply is connected. On the other hand, the two input-output terminals TI function as output terminals of the DAB converter 1 when a load is connected. In addition, the two input-output terminals TO function as input terminals of the DAB converter 1 when a DC power supply is connected. On the other hand, the two input-output terminals TO function as output terminals of the DAB converter 1 when a load is connected.

[0035] The transformer T has a primary winding T1 and a secondary winding T2.

[0036] The first full-bridge circuit B1 is an H-bridge circuit having four switch elements S1. In the following, for the sake of convenience, the four switch elements S1 are referred to as switch element S11, switch element S12, switch element S13, and switch element S14. Figure 1 As shown, one of the two midpoints of the first full-bridge circuit B1 is referred to as a midpoint P11 , and the other of the two midpoints of the first full-bridge circuit B1 is referred to as a midpoint P12 . Figure 1 In the example shown, the midpoint P11 is the connection point between the switching element S11 and the switching element S12. In addition, in this example, the midpoint P12 is the connection point between the switching element S13 and the switching element S14.

[0037] The switching element S1 may be any switching element such as a field effect transistor, a bipolar transistor, or a relay switch as long as it can be switched under the control of the control unit 11. Hereinafter, as an example, a case where the switching element S1 is a field effect transistor will be described.

[0038] in addition, Figure 1 In the first full-bridge circuit B1 shown, the switch element S11 and the switch element S13 constitute the upper arm A11 of the first full-bridge circuit B1. In the following, for the convenience of explanation, the connection point of the switch element S11 and the switch element S13 is referred to as the input-output terminal P13 and is explained. The input-output terminal P13 is one of the two input-output terminals of the first full-bridge circuit B1. Here, the input-output terminal P13 acts as one of the two input terminals of the first full-bridge circuit B1 when a DC power supply is connected to the two input-output terminals TI. On the other hand, the input-output terminal P13 acts as one of the two output terminals of the first full-bridge circuit B1 when a load is connected to the two input-output terminals TI.

[0039] in addition, Figure 1 In the first full-bridge circuit B1 shown, the switch element S12 and the switch element S14 constitute the lower arm A12 of the first full-bridge circuit B1. In the following, for the convenience of explanation, the connection point of the switch element S12 and the switch element S14 is referred to as the input-output terminal P14 and is explained. The input-output terminal P14 is the other of the two input-output terminals of the first full-bridge circuit B1. Here, the input-output terminal P14 acts as the other of the two input terminals of the first full-bridge circuit B1 when a DC power supply is connected to the two input-output terminals TI. On the other hand, the input-output terminal P14 acts as the other of the two output terminals of the first full-bridge circuit B1 when a load is connected to the two input-output terminals TI.

[0040] The first full-bridge circuit B1 is connected in parallel with the first capacitor C1 between the input-output terminal TI1 and the input-output terminal TI2 . Figure 1In the example shown, one of the two terminals of the first capacitor C1 and the above-mentioned input-output terminal P13 are connected to the input-output terminal TI1. In addition, in this example, the other of the two terminals of the first capacitor C1 and the above-mentioned input-output terminal P14 are connected to the input-output terminal TI2. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the first capacitor C1 and the input-output terminal TI1. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the input-output terminal P13 and the input-output terminal TI1. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the first capacitor C1 and the input-output terminal TI2. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the input-output terminal P14 and the input-output terminal TI2.

[0041] The second full-bridge circuit B2 is an H-bridge circuit having four switch elements S2. In the following, for the sake of convenience, the four switch elements S2 are referred to as switch element S21, switch element S22, switch element S23, and switch element S24. Figure 1 As shown, one of the two midpoints of the second full-bridge circuit B2 is referred to as a midpoint P21, and the other of the two midpoints of the second full-bridge circuit B2 is referred to as a midpoint P22 for description. Figure 1 In the example shown, the midpoint P21 is the connection point between the switching element S21 and the switching element S22. In this example, the midpoint P22 is the connection point between the switching element S23 and the switching element S24.

[0042] The switch element S2 may be any switch element such as a field effect transistor, a bipolar transistor, or a relay switch as long as it can be switched according to the control of the control unit 11. Hereinafter, as an example, a case where the switch element S2 is a field effect transistor will be described.

[0043] in addition, Figure 1In the second full-bridge circuit B2 shown, the switch element S21 and the switch element S23 constitute the upper arm A21 of the second full-bridge circuit B2. In the following, for the sake of convenience, the connection point of the switch element S21 and the switch element S23 is referred to as the input-output terminal P23 and is described. The input-output terminal P23 is one of the two input-output terminals of the second full-bridge circuit B2. Here, the input-output terminal P23 acts as one of the two input terminals of the second full-bridge circuit B2 when a DC power supply is connected to the two input-output terminals TO. On the other hand, the input-output terminal P23 acts as one of the two output terminals of the second full-bridge circuit B2 when a load is connected to the two input-output terminals TO.

[0044] in addition, Figure 1 In the second full-bridge circuit B2 shown, the switch element S22 and the switch element S24 constitute the lower arm A22 of the second full-bridge circuit B2. In the following, for the sake of convenience, the connection point of the switch element S22 and the switch element S24 is referred to as the input-output terminal P24 and is described. The input-output terminal P24 is the other of the two input-output terminals of the second full-bridge circuit B2. Here, the input-output terminal P24 acts as the other of the two input terminals of the second full-bridge circuit B2 when a DC power supply is connected to the two input-output terminals TO. On the other hand, the input-output terminal P24 acts as the other of the two output terminals of the second full-bridge circuit B2 when a load is connected to the two input-output terminals TO.

[0045] The second full-bridge circuit B2 is connected in parallel with the second capacitor C2 between the input / output terminal TO1 and the input / output terminal TO2. Figure 1 In the example shown, one of the two terminals of the second capacitor C2 and the above-mentioned input-output terminal P23 are connected to the input-output terminal TO1. In addition, in this example, the other of the two terminals of the second capacitor C2 and the above-mentioned input-output terminal P24 are connected to the input-output terminal TO2. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the second capacitor C2 and the input-output terminal TO1. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the input-output terminal P23 and the input-output terminal TO1. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the second capacitor C2 and the input-output terminal TO2. In addition, it is also possible to have a structure in which other circuit elements are connected in series or in parallel between the input-output terminal P24 and the input-output terminal TO2.

[0046] Here, the inductance of the DAB converter 1 is a combined inductance of the inductance of the primary side circuit of the DAB converter 1 and the inductance of the secondary side circuit of the DAB converter 1 .

[0047] The inductance of the primary side circuit of the DAB converter 1 is represented by, for example, the inductance of a portion connected between the midpoint P11 and the midpoint P12 among the portions of the primary side circuit of the DAB converter 1. Hereinafter, for the sake of convenience, this portion will be referred to as the first portion PT1 and described. In addition, the inductance of the primary side circuit of the DAB converter 1 may be represented by the inductance of the first portion PT1 and the inductance of a portion other than the first portion PT1 among the portions of the primary side circuit of the DAB converter 1.

[0048] Figure 1 In the example shown, the first inductor L1 and the primary winding T1 are connected in series between the midpoint P11 and the midpoint P12. That is, in this example, the first part PT1 includes the first inductor L1 and the primary winding T1 connected in series with the first inductor L1. Therefore, in this example, the inductance of the first part PT1 is the composite inductance of the inductance of the first inductor L1 and the leakage inductance of the primary winding T1. In addition, it is also possible to have a structure in which the first inductor L1 and the primary winding T1, as well as other circuit elements such as a capacitor, are connected in series or in parallel between the midpoint P11 and the midpoint P12. In addition, when the DAB converter 1 does not have the first inductor L1, the first part PT1 does not include the first inductor L1, but includes the primary winding T1. In this case, the inductance of the first part PT1 is the leakage inductance of the primary winding T1.

[0049] In addition, in the DAB converter 1, by winding the conductor wound as the primary side winding T1 so that the intervals between the conductors are not dense at the winding start and winding end, the leakage inductance of the primary side winding T1 can be increased, and it can function as a substitute for the first inductor L1. On the other hand, in the DAB converter 1, when the DAB converter 1 includes the first inductor L1, it is desirable to wind the conductor wound as the primary side winding T1 so that the intervals between the conductors are dense at the winding start and winding end.

[0050] The first inductor L1 is, for example, a choke coil. In addition, the first inductor L1 may be another circuit element or another member as long as it is a circuit element or another member that functions similarly to the choke coil.

[0051] The inductance of the secondary side circuit of the DAB converter 1 is represented by, for example, the inductance of a portion connected between the midpoint P21 and the midpoint P22 among the portions of the secondary side circuit of the DAB converter 1. Hereinafter, for the sake of convenience, this portion will be referred to as the second portion PT2 and described. In addition, the inductance of the secondary side circuit of the DAB converter 1 may be represented by the inductance of the second portion PT2 and the inductance of a portion other than the second portion PT2 among the portions of the secondary side circuit of the DAB converter 1.

[0052] Figure 1 In the example shown, the second inductor L2 and the secondary winding T2 are connected in series between the midpoint P21 and the midpoint P22. That is, in this example, the second part PT2 includes the second inductor L2 and the secondary winding T2 connected in series with the second inductor L2. Therefore, in this example, the inductance of the second part PT2 is the composite inductance of the inductance of the second inductor L2 and the leakage inductance of the secondary winding T2. In addition, it is also possible to have a structure in which the second inductor L2 and the secondary winding T2, as well as other circuit elements such as a capacitor, are connected in series or in parallel between the midpoint P21 and the midpoint P22. In addition, when the DAB converter 1 does not have the second inductor L2, the second part PT2 does not include the second inductor L2, but includes the secondary winding T2. In this case, the inductance of the second part PT2 is the leakage inductance of the secondary winding T2.

[0053] In addition, in the DAB converter 1, by winding the conductor wound as the secondary winding T2 in a manner that the intervals between the conductors are not dense at the winding start and winding end, the leakage inductance of the secondary winding T2 can be increased, and it can function as a substitute for the second inductor L2. On the other hand, in the DAB converter 1, when the DAB converter 1 includes the second inductor L2, it is desirable to wind the conductor wound as the secondary winding T2 in a manner that the intervals between the conductors are dense at the winding start and winding end.

[0054] The second inductor L2 is, for example, a choke coil. In addition, the second inductor L2 may be other circuit elements or other components as long as they are circuit elements or components that play the same role as the choke coil.

[0055] Here, Figure 1 In the example shown, a DC power source (not shown) is connected to the input / output terminal TI1 and the input / output terminal TI2 of the DAB converter 1. In addition, a load is connected to the input / output terminal TO1 and the input / output terminal TO2 of the DAB converter 1. Figure 1In the example shown, as an example of such a load, a load LD is connected to the DAB converter 1. The load LD may be any load as long as it can be connected to the DAB converter 1. For example, the load LD is a battery. That is, Figure 1 In the illustrated example, the DAB converter 1 supplies electric power supplied from a DC power source connected to the DAB converter 1 to the load LD.

[0056] However, the inductance of the DAB converter 1 varies greatly among individuals, and thus, if some adjustment is not made, the more the inductance of the DAB converter 1 deviates from the designed value, the lower the power transmission efficiency of the DAB converter 1 may become.

[0057] Therefore, the control unit 11 adjusts the phase difference between the switches of the first full bridge circuit B1 and the switches of the second full bridge circuit B2 based on the estimated value of the inductance of the DAB converter 1. Thus, the DAB converter 1 can suppress a decrease in power transmission efficiency due to individual differences in inductance.

[0058] In the present embodiment, the switches of the first full-bridge circuit B1 are switches of the four switch elements S1 of the first full-bridge circuit B1. In addition, in the present embodiment, the switches of the second full-bridge circuit B2 are switches of the four switch elements S2 of the second full-bridge circuit B2. Moreover, in the present embodiment, the phase difference between the switches of the first full-bridge circuit B1 and the switches of the second full-bridge circuit B2 represents four phase differences of the first phase difference to the fourth phase difference described below.

[0059] The first phase difference is the phase difference between the switching of the switching element S11 and the switching of the switching element S21. More specifically, the first phase difference is the phase deviation between the square wave input to the gate terminal of the switching element S11 and the square wave input to the gate terminal of the switching element S21. When the DAB converter 1 is normally used, a square wave is input to the gate terminal of the switching element S11 from the control unit 11. In other words, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S11, so that the state of the switching element S11 changes periodically between the on state and the off state as time passes. In addition, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S21, so that the state of the switching element S21 changes periodically between the on state and the off state as time passes. That is, the phase difference between the two square waves represents the phase difference between the switching of the switching element S11 and the switching of the switching element S21.

[0060] The second phase difference is the phase difference between the switching of the switching element S12 and the switching of the switching element S22. More specifically, the second phase difference is the phase deviation between the square wave input to the gate terminal of the switching element S12 and the square wave input to the gate terminal of the switching element S22. When the DAB converter 1 is normally used, a square wave is input to the gate terminal of the switching element S12 from the control unit 11. In other words, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S12, so that the state of the switching element S12 changes periodically between the on state and the off state as time passes. In addition, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S22, so that the state of the switching element S22 changes periodically between the on state and the off state as time passes. That is, the phase difference between the two square waves represents the phase difference between the switching of the switching element S12 and the switching of the switching element S22.

[0061] The third phase difference is the phase difference between the switching of the switching element S13 and the switching of the switching element S23. More specifically, the third phase difference is the phase deviation between the square wave input to the gate terminal of the switching element S13 and the square wave input to the gate terminal of the switching element S23. When the DAB converter 1 is normally used, a square wave is input to the gate terminal of the switching element S13 from the control unit 11. In other words, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S13, so that the state of the switching element S13 changes periodically between the on state and the off state as time passes. In addition, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S23, so that the state of the switching element S23 changes periodically between the on state and the off state as time passes. That is, the phase difference between the two square waves represents the phase difference between the switching of the switching element S13 and the switching of the switching element S23.

[0062] The fourth phase difference is the phase difference between the switching of the switching element S14 and the switching of the switching element S24. More specifically, the fourth phase difference is the phase deviation between the square wave input to the gate terminal of the switching element S14 and the square wave input to the gate terminal of the switching element S24. When the DAB converter 1 is normally used, a square wave is input to the gate terminal of the switching element S14 from the control unit 11. In other words, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S14, so that the state of the switching element S14 changes periodically between the on state and the off state as time passes. In addition, when the DAB converter 1 is normally used, the control unit 11 inputs a square wave to the gate terminal of the switching element S24, so that the state of the switching element S24 changes periodically between the on state and the off state as time passes. That is, the phase difference between the two square waves represents the phase difference between the switching of the switching element S14 and the switching of the switching element S24.

[0063] In the present embodiment, adjusting the phase difference between the switches of the first full-bridge circuit B1 and the switches of the second full-bridge circuit B2 means changing at least one of the four phase differences of the first phase difference to the fourth phase difference.

[0064] In the following, for the sake of convenience, the estimated value of the inductance of the DAB converter 1 is simply referred to as an estimated value. In the following, for the sake of convenience, the phase difference between the switches of the first full bridge circuit B1 and the switches of the second full bridge circuit B2 is simply referred to as a phase difference.

[0065] The control unit 11 adjusts the phase difference based on an estimated value estimated by the information processing device 2 described later. Alternatively, the control unit 11 may estimate the estimated value and adjust the phase difference based on the estimated value.

[0066] The information processing device 2 is, for example, a personal computer (Personal Computer), a tablet computer, a desktop computer, a workstation, a multi-function mobile terminal (smartphone), a mobile terminal, a PDA (Personal Digital Assistant), etc., but is not limited thereto.

[0067] As described above, the information processing device 2 estimates the estimated value. More specifically, the information processing device 2 estimates the estimated value based on, for example, the input voltage to the DAB converter 1, the input current to the DAB converter 1, and the output voltage from the DAB converter 1. Therefore, the DAB converter 1 is equipped with a voltage detection unit that detects the input voltage to the DAB converter 1, a current detection unit that detects the input current to the DAB converter 1, and a voltage detection unit that detects the output voltage from the DAB converter 1. Figure 1In the illustrated example, the DAB converter 1 is equipped with a first voltage detection unit DV1 , a first current detection unit DC1 , and a second voltage detection unit DV2 .

[0068] The first voltage detection unit DV1 is a voltmeter. The first voltage detection unit DV1 is mounted on the DAB converter 1 in a manner capable of detecting a voltage applied between two input / output terminals TI of the DAB converter 1. More specifically, the first voltage detection unit DV1 is mounted on the DAB converter 1 in a manner capable of detecting a voltage applied between two input / output terminals (i.e., input / output terminal P13 and input / output terminal P14) of the first full-bridge circuit B1. In addition, the first voltage detection unit DV1 is mounted on the DAB converter 1 in a manner capable of communicating with the information processing device 2. Figure 1 In the example shown, the first voltage detection unit DV1 is connected between two transmission paths that connect the power supply terminal of the DC power supply (not shown) and the two input / output terminals (i.e., the input / output terminal TI1 and the input / output terminal TI2) of the DAB converter 1. Thus, the first voltage detection unit DV1 can detect the voltage applied between the two input / output terminals of the first full-bridge circuit B1. In addition, hereinafter, for the sake of convenience, the voltage detected by the first voltage detection unit DV1 will be referred to as the first voltage and described. The first voltage detection unit DV1 outputs first voltage information indicating the detected first voltage to the information processing device 2.

[0069] The first current detection unit DC1 is an ammeter. The first current detection unit DC1 is mounted on the DAB converter 1 in a manner capable of detecting a current flowing through the input-output terminal TI1 connected to the power terminal on the positive side of the DC power supply, of the two input-output terminals TI of the DAB converter 1. More specifically, the first current detection unit DC1 is mounted on the DAB converter 1 in a manner capable of detecting a current flowing through the input-output terminal P13 connected to the input-output terminal TI1, of the two input-output terminals (i.e., the input-output terminal P13 and the input-output terminal P14) of the first full-bridge circuit B1. In addition, the first current detection unit DC1 is mounted on the DAB converter 1 in a manner capable of communicating with the information processing device 2. Figure 1 In the example shown, the first current detection unit DC1 is connected to a transmission path that connects the power supply terminal of a DC power supply (not shown) and the input / output terminal TI1. Thus, the first current detection unit DC1 can detect the current flowing between the two input / output terminals of the first full-bridge circuit B1, the input / output terminal on which the current is supplied from the DC power supply. In addition, hereinafter, for the sake of convenience, the current detected by the first current detection unit DC1 will be referred to as the first current and described. The first current detection unit DC1 outputs first current information indicating the detected first current to the information processing device 2.

[0070] The second voltage detection unit DV2 is a voltmeter. The second voltage detection unit DV2 is mounted on the DAB converter 1 in a manner capable of detecting a voltage applied between two input / output terminals TO of the DAB converter 1. More specifically, the second voltage detection unit DV2 is mounted on the DAB converter 1 in a manner capable of detecting a voltage applied between two input / output terminals (i.e., input / output terminal P23 and input / output terminal P24) of the second full-bridge circuit B2. In addition, the second voltage detection unit DV2 is mounted on the DAB converter 1 in a manner capable of communicating with the information processing device 2. Figure 1 In the example shown, the second voltage detection unit DV2 is connected between two transmission paths that connect the load LD and the two input / output terminals (i.e., the input / output terminal TO1 and the input / output terminal TO2) of the DAB converter 1. Thus, the second voltage detection unit DV2 can detect the voltage applied between the two input / output terminals of the second full-bridge circuit B2. In addition, hereinafter, for the sake of convenience, the voltage detected by the second voltage detection unit DV2 will be referred to as the second voltage and described. The second voltage detection unit DV2 outputs second voltage information indicating the detected second voltage to the information processing device 2.

[0071] The information processing device 2 estimates the estimated value based on the first voltage detected by the first voltage detection unit DV1, the first current detected by the first current detection unit DC1, and the second voltage detected by the second voltage detection unit DV2. More specifically, the information processing device 2 calculates the estimated value using the first voltage, the first current, the second voltage, and the following formula (1).

[0072] [Formula 1]

[0073]

[0074] Here, P shown in the above formula (1) represents the power supplied from the DC power supply to the DAB converter 1. V1 shown in the above formula (1) represents the first voltage. V2 shown in the above formula (1) represents the second voltage. N1 shown in the above formula (1) represents the number of turns of the primary side winding T1. N2 shown in the above formula (1) represents the number of turns of the secondary side winding T2. ω shown in the above formula (1) represents the angular frequency of the switches of the first full-bridge circuit B1 and the second full-bridge circuit B2. δ shown in the above formula (1) represents the phase difference. And, L shown in the above formula (1) represents the inductance of the DAB converter 1. In addition, among these parameters, the parameters known to the information processing device 2 are the primary side winding T1, the secondary side winding T2, the angular frequency ω, and the phase difference δ.

[0075] For example, the information processing device 2 calculates the power P based on the first voltage V1 and the first current. The information processing device 2 estimates (calculates) the value of the combined inductance L as the above-mentioned estimated value based on the calculated power P, the first voltage V1, the second voltage V2, the primary winding T1, the secondary winding T2, the angular frequency ω, and the phase difference δ.

[0076] After estimating the estimated value, the information processing device 2 outputs estimated value information indicating the estimated value to the control unit 11 of the DAB converter 1. The control unit 11 adjusts the phase difference based on the estimated value indicated by the acquired estimated value information. For example, when the estimated value is larger than the designed value (i.e., the predetermined inductance), the control unit 11 adjusts the phase difference to, for example, Figure 2 The phase difference shown. Figure 2 This is a diagram showing an example of the phase difference after adjustment by the control unit 11 when the estimated value is larger than the designed value.

[0077] Figure 2 The graph TL11 shown is a graph showing an example of the temporal change of the state of the switching element S11. In the graph TL11, the period when the state of the switching element S11 is in the on state is represented by the period when the displacement of the square wave shown in the graph TL11 is consistent with "ON". In addition, in the graph TL11, the period when the state of the switching element S11 is in the off state is represented by the period when the displacement of the square wave shown in the graph TL11 is consistent with "OFF". In addition, since the square wave representing the temporal change of the state of the switching element S12 is a square wave whose phase is offset by 2π from the square wave representing the temporal change of the state of the switching element S11, it is omitted from the diagram.

[0078] in addition, Figure 2 The graph TL13 shown is a graph showing an example of the temporal change of the state of the switching element S13. In the graph TL13, the period when the state of the switching element S13 is in the on state is represented by the period when the displacement of the square wave shown in the graph TL13 is consistent with "ON". In addition, in the graph TL13, the period when the state of the switching element S13 is in the off state is represented by the period when the displacement of the square wave shown in the graph TL13 is consistent with "OFF". In addition, since the square wave representing the temporal change of the state of the switching element S14 is a square wave whose phase is offset by 2π from the square wave representing the temporal change of the state of the switching element S13, it is omitted from the diagram.

[0079] Figure 2The graph TL21 shown is a graph showing an example of the temporal change of the state of the switching element S21. In the graph TL21, the period when the state of the switching element S21 is in the on state is represented by the period when the displacement of the square wave shown in the graph TL21 is consistent with "ON". In addition, in the graph TL21, the period when the state of the switching element S21 is in the off state is represented by the period when the displacement of the square wave shown in the graph TL21 is consistent with "OFF". In addition, since the square wave representing the temporal change of the state of the switching element S22 is a square wave whose phase is offset by 2π from the square wave representing the temporal change of the state of the switching element S21, it is omitted from the diagram.

[0080] in addition, Figure 2 The graph TL23 shown is a graph showing an example of the temporal change of the state of the switching element S23. In the graph TL23, the period when the state of the switching element S23 is in the on state is represented by the period when the displacement of the square wave shown in the graph TL23 is consistent with "ON". In addition, in the graph TL23, the period when the state of the switching element S23 is in the off state is represented by the period when the displacement of the square wave shown in the graph TL23 is consistent with "OFF". In addition, since the square wave representing the temporal change of the state of the switching element S24 is a square wave whose phase is offset by 2π from the square wave representing the temporal change of the state of the switching element S23, it is omitted from the diagram.

[0081] like Figure 2 As shown, when the estimated value is larger than the design value, the control unit 11 sets the first phase difference and the second phase difference to zero. In addition, when the estimated value is larger than the design value, the control unit 11 changes the third phase difference and the fourth phase difference to non-zero values. The magnitude of the value depends on the circuit structure of the DAB converter 1. Therefore, in this embodiment, a specific value is omitted as an example of the value.

[0082] Here, if Figure 2 As shown, graph DL1 shows an example of temporal change of the voltage applied to both ends of the first part PT1 when the third phase difference and the fourth phase difference are changed to non-zero values. In other words, graph DL1 shows an example of temporal change of the voltage applied between the input-output terminal P13 and the input-output terminal P14. In addition, graph DL2 shows an example of temporal change of the voltage applied to both ends of the second part PT2 in this case. In other words, graph DL2 shows an example of temporal change of the voltage applied between the input-output terminal P23 and the input-output terminal P24.

[0083] That is, when the estimated value is larger than the designed value, the control unit 11 shortens the time width for applying the voltage to both ends of the first part PT1 compared to the time width for applying the voltage to both ends of the second part PT2, for example, as shown in the graphs DL1 and DL2. In other words, the control unit 11 adjusts the phase difference between the phase of the square wave representing the temporal change of the voltage applied to both ends of the first part PT1 and the phase of the square wave representing the temporal change of the voltage applied to both ends of the second part PT2 by adjusting the first phase difference and the second phase difference in this case. Thus, the control unit 11 Figure 1 In the circuit configuration of the DAB converter 1 shown, it is possible to suppress a decrease in the power transmission efficiency.

[0084] In addition, for example, when the estimated value is smaller than the design value (that is, the predetermined inductance), the control unit 11 adjusts the phase difference to, for example, Figure 3 The phase difference shown. Figure 3 This is a diagram showing an example of the phase difference after adjustment by the control unit 11 when the estimated value is smaller than the designed value.

[0085] Figure 3 The graph TL31 shown is another example of a graph showing the temporal change in the state of the switching element S11. In the graph TL31, the period during which the state of the switching element S11 is in the on state is represented by the period during which the displacement of the square wave shown in the graph TL31 coincides with "ON". In addition, in the graph TL31, the period during which the state of the switching element S11 is in the off state is represented by the period during which the displacement of the square wave shown in the graph TL31 coincides with "OFF". In addition, since the square wave showing the temporal change in the state of the switching element S12 is a square wave whose phase is offset by 2π from the square wave showing the temporal change in the state of the switching element S11, it is omitted from the diagram.

[0086] in addition, Figure 3 The graph TL33 shown is another example of a graph showing the temporal change in the state of the switching element S13. In the graph TL33, the period during which the state of the switching element S13 is in the on state is represented by the period during which the displacement of the square wave shown in the graph TL33 coincides with "ON". In addition, in the graph TL33, the period during which the state of the switching element S13 is in the off state is represented by the period during which the displacement of the square wave shown in the graph TL33 coincides with "OFF". In addition, since the square wave showing the temporal change in the state of the switching element S14 is a square wave whose phase is offset by 2π from the square wave showing the temporal change in the state of the switching element S13, it is omitted from the diagram.

[0087] Figure 3The graph TL41 shown is a graph showing another example of the temporal change in the state of the switching element S21. In the graph TL41, the period during which the state of the switching element S21 is in the on state is represented by the period during which the displacement of the square wave shown in the graph TL41 coincides with "ON". In addition, in the graph TL41, the period during which the state of the switching element S21 is in the off state is represented by the period during which the displacement of the square wave shown in the graph TL41 coincides with "OFF". In addition, since the square wave representing the temporal change in the state of the switching element S22 is a square wave whose phase is offset by 2π from the square wave representing the temporal change in the state of the switching element S21, it is omitted from the diagram.

[0088] in addition, Figure 3 The graph TL43 shown is another example of a graph showing a temporal change in the state of the switching element S23. In the graph TL43, the period during which the state of the switching element S23 is in the on state is represented by the period during which the displacement of the square wave shown in the graph TL43 coincides with "ON". In addition, in the graph TL43, the period during which the state of the switching element S23 is in the off state is represented by the period during which the displacement of the square wave shown in the graph TL43 coincides with "OFF". In addition, since the square wave showing the temporal change in the state of the switching element S24 is a square wave whose phase is offset by 2π from the square wave showing the temporal change in the state of the switching element S23, it is omitted from the diagram.

[0089] Figure 3 In the example shown, when the estimated value is smaller than the design value, the control unit 11 changes the first phase difference and the second phase difference to non-zero values. In addition, in this example, the control unit 11 changes the third phase difference and the fourth phase difference to non-zero values ​​in this case. That is, in this example, in this case, the control unit 11 changes each of the first phase difference to the fourth phase difference to a non-zero value. The magnitudes of these four non-zero values ​​depend on the circuit structure of the DAB converter 1. Therefore, in this embodiment, specific values ​​are omitted as examples of these four non-zero values.

[0090] Here, if Figure 3 As shown, graph DL3 shows an example of temporal change of the voltage applied to both ends of the first part PT1 when each of the first to fourth phase differences is changed to a non-zero value. In other words, graph DL3 shows an example of temporal change of the voltage applied between the input / output terminal P13 and the input / output terminal P14. In addition, graph DL4 shows an example of temporal change of the voltage applied to both ends of the second part PT2 in this case. In other words, graph DL4 shows an example of temporal change of the voltage applied between the input / output terminal P23 and the input / output terminal P24.

[0091] That is, when the estimated value is smaller than the designed value, the control unit 11 shortens the time width for applying the voltage to both ends of the first portion PT1 compared to the time width for applying the voltage to both ends of the second portion PT2, for example, as shown in the graphs DL3 and DL4. In other words, the control unit 11 adjusts the phase difference between the phase of the square wave representing the temporal change of the voltage applied to both ends of the first portion PT1 and the phase of the square wave representing the temporal change of the voltage applied to both ends of the second portion PT2 by adjusting the first phase difference and the second phase difference in this case. Thus, the control unit 11 Figure 1 In the circuit configuration of the DAB converter 1 shown, it is possible to suppress a decrease in the power transmission efficiency.

[0092] also, Figure 2 and Figure 3 The method for adjusting the phase difference by the control unit 11 may be other known methods, instead of the method described above, or may be a method developed therefrom. Therefore, in this embodiment, further detailed description of the method for adjusting the phase difference by the control unit 11 is omitted.

[0093] In addition, the information processing device 2 may also be configured to estimate the estimated value based on the first voltage, the first current, and the second voltage instead of, or in addition to, the first voltage, the first current, and the second voltage. The second current is determined by Figure 4 The second current detection unit DC2 shown detects the current.

[0094] Figure 4 1 is a diagram showing an example of the configuration of a DAB converter 1 in which a second current detection unit DC2 is provided instead of the first current detection unit DC1 .

[0095] Figure 4 In the example shown, a load LD is connected to two input / output terminals TI of the DAB converter 1. In addition, in this example, a DC power supply (not shown) is connected to two input / output terminals TO of the DAB converter 1. That is, Figure 4 In the DAB converter 1 shown in FIG. 1 , the relationship between the input and output of the DAB converter 1 is replaced by Figure 1 The DAB converter 1 is shown.

[0096] The second current detection unit DC2 is an ammeter. The second current detection unit DC2 is installed in the DAB converter 1 in a manner that can detect the current flowing through the input-output terminal TO1 connected to the power terminal on the positive side of the DC power supply, of the two input-output terminals TO of the DAB converter 1. More specifically, the second current detection unit DC2 is installed in the DAB converter 1 in a manner that can detect the current flowing from the input-output terminal P23 connected to the input-output terminal TO1, of the two input-output terminals (i.e., the input-output terminal P23 and the input-output terminal P24) of the second full-bridge circuit B2, to the load LD. In addition, the second current detection unit DC2 is installed in the DAB converter 1 in a manner that can communicate with the information processing device 2. Figure 1 In the example shown, the second current detection unit DC2 is connected to the transmission path connecting the power supply terminal on the positive side of the load LD and the input / output terminal TO1. Thus, the second current detection unit DC2 can detect the current flowing from the positive side input / output terminal of the two input / output terminals of the second full-bridge circuit B2 to the load LD. The second current detection unit DC2 outputs the second current information indicating the detected second current to the information processing device 2.

[0097] When the second current detection unit DC2 is installed in the DAB converter 1, the information processing device 2 estimates the estimated value based on the following equation (2), for example.

[0098] [Formula 2]

[0099]

[0100] Even in this case, the information processing device 2 can estimate the estimated value. Furthermore, the control unit 11 can adjust the phase difference based on the estimated value indicated by the estimated value information acquired from the information processing device 2. As a result, the control unit 11 Figure 4 In the circuit configuration of the DAB converter 1 shown, it is possible to suppress a decrease in the power transmission efficiency.

[0101] In addition, as described above, the control unit 11 may be a structure that estimates the estimated value instead of the information processing device 2. In this case, at least a part of the functions described above among the functions of the information processing device 2 is provided in the control unit 11. Therefore, in this case, the DAB converter 1 may be a structure that is not connected to the information processing device 2. In addition, in this case, the first voltage detection unit DV1 is installed in the DAB converter 1 in a manner that can communicate with the control unit 11. In addition, in this case, the first current detection unit DC1 is installed in the DAB converter 1 in a manner that can communicate with the control unit 11. In addition, in this case, the second voltage detection unit DV2 is installed in the DAB converter 1 in a manner that can communicate with the control unit 11.

[0102] In addition, the first voltage detection unit DV1 may be a structure built into the DAB converter 1 instead of being external to the DAB converter 1. In addition, the first current detection unit DC1 may be a structure built into the DAB converter 1 instead of being external to the DAB converter 1. In addition, the second voltage detection unit DV2 may be a structure built into the DAB converter 1 instead of being external to the DAB converter 1.

[0103] <Processing of Information Processing Device Estimating Estimated Value and Processing of Control Unit Adjusting Phase Difference>

[0104] In the following, reference is made to Figure 5 The process of estimating the estimated value by the information processing device 2 and the process of adjusting the phase difference by the control unit 11 will be described. Figure 5 1 is a sequence diagram showing an example of the process flow of the information processing device 2 estimating the estimated value and the control unit 11 adjusting the phase difference. Figure 5 The case where the DAB converter 1 receives an operation to change the operation mode of the DAB converter 1 to the adjustment mode at a time before the processing of step S210 shown in FIG. 1 is described. Here, the adjustment mode in the operation mode of the DAB converter 1 is a mode in which the phase difference is adjusted based on the estimated value information acquired from the information processing device 2 when the estimated value information is acquired from the information processing device 2. In addition, the DAB converter 1 may perform this operation via a hardware key possessed by the DAB converter 1, or may perform this operation via the information processing device 2 connected to the DAB converter 1, etc. In addition, as an example, the case where the information processing device 2 receives an operation to change the operation mode of the information processing device 2 to the adjustment mode at this time is described. Here, the adjustment mode in the operation mode of the information processing device 2 is a mode in which the information processing device 2 estimates the estimated value, outputs the estimated value information indicating the estimated estimated value to the DAB converter 1, and adjusts the phase difference of the DAB converter 1. In addition, the information processing device 2 may perform this operation via a hardware key possessed by the information processing device 2, or may perform this operation via a software key displayed on the display unit (e.g., display) of the information processing device 2.

[0105] The information processing device 2 detects the voltage and current (step S210). Specifically, for example, the information processing device 2 detects the first voltage represented by the first voltage information obtained by acquiring the first voltage information from the first voltage detection unit DV1 in step S210. In addition, for example, the information processing device 2 detects the first current represented by the first current information obtained by acquiring the first current information from the first current detection unit DC1 in step S210. In addition, for example, the information processing device 2 detects the second voltage represented by the second voltage information obtained by acquiring the second voltage information from the second voltage detection unit DV2 in step S210.

[0106] Next, the information processing device 2 estimates an estimated value based on the first voltage, the first current, and the second voltage detected in step S210 (step S220). An example of the method for estimating the estimated value in step S220 has been described, and thus the description thereof is omitted.

[0107] Next, the information processing device 2 generates estimated value information indicating the estimated value estimated in step S220, and outputs the generated estimated value information to the DAB converter 1 (step S230).

[0108] Next, the control unit 11 acquires the estimated value information output from the information processing device 2 (step S110 ).

[0109] Next, the control unit 11 adjusts the phase difference based on the estimated value represented by the estimated value information obtained in step S110 (step S120). For example, a plurality of phase difference information is pre-stored in the DAB converter 1. Here, the phase difference information is information including information for adjusting one or both of the switches of the first full-bridge circuit B1 and the switches of the second full-bridge circuit B2. Moreover, a non-overlapping range of the estimated value corresponds to each of the plurality of phase difference information. Here, for example, when the estimated value represented by the estimated value information obtained in step S110 is included in a range X2 corresponding to a certain phase difference information X1 among the plurality of phase difference information pre-stored in the DAB converter 1, the control unit 11 specifies the phase difference information X1 as the phase difference information corresponding to the estimated value. The control unit 11 adjusts the phase difference based on the specific phase difference information X1. More specifically, the control unit 11 changes the current phase difference to the phase difference represented by the specific phase difference information X1. Thus, the control unit 11 adjusts the phase difference. In addition, as described above, the method for adjusting the phase difference by the control unit 11 may be other known methods instead of the method described above, or a method developed therefrom. In addition, the control unit 11 may also be configured to calculate or generate phase difference information corresponding to the estimated value estimated in step S120.

[0110] After performing the process of step S120 , the control unit 11 changes the operation mode of the DAB converter 1 from the adjustment mode to the normal operation mode, and ends the process.

[0111] In this way, the DAB converter 1 adjusts the phase difference based on the estimated value estimated by the information processing device 2. Thus, the DAB converter 1 can suppress a decrease in the power transmission efficiency due to individual differences in inductance.

[0112] <Modification of Implementation>

[0113] In the following, a modified example of the embodiment is described. In addition, in the modified example of the embodiment, the same symbols are marked on the same components as in the embodiment and the description is omitted. In the modified example of the embodiment, the control unit 11 estimates the estimated value instead of the structure that obtains the estimated value information from the information processing device 2. In addition, the control unit 11 estimates the estimated value by a method different from that in the embodiment. In addition, in the modified example of the embodiment, Figure 6 As shown in FIG. 1 , the DAB converter 1 includes a third voltage detection unit DV3 instead of the first voltage detection unit DV1. Figure 6 As shown in FIG. 1 , the DAB converter 1 includes a third current detection unit DC3 instead of the first current detection unit DC1. Figure 6 As shown, the DAB converter 1 includes a fourth voltage detection unit DV4 instead of the second voltage detection unit DV2. In addition, the DAB converter 1 may also be a structure that does not include each of the third voltage detection unit DV3, the third current detection unit DC3, and the fourth voltage detection unit DV4. In this case, the DAB converter 1 is externally connected to each of the third voltage detection unit DV3, the third current detection unit DC3, and the fourth voltage detection unit DV4. In addition, the DAB converter 1 may also be a structure that includes each of the third voltage detection unit DV3, the third current detection unit DC3, and the fourth voltage detection unit DV4, and each of the first voltage detection unit DV1, the first current detection unit DC1, the second voltage detection unit DV2, and the second current detection unit DC2 is installed. In this case, the control unit 11 may also perform the estimation of the estimated value by the method described in the embodiment in addition to the estimation of the estimated value by the method described in the modified example of the embodiment. In addition, in the DAB converter 1 of the modification of the embodiment, as in the DAB converter 1 of the embodiment, the information processing device 2 may be connected, and the information processing device 2 may estimate the estimated value by the estimation method described in the modification of the embodiment. In this case, the information processing device 2 outputs the estimated value information indicating the estimated estimated value to the control unit 11 as in the embodiment.

[0114] Figure 61 is a diagram showing an example of the structure of a DAB converter 1 of a modified example of the embodiment. The DAB converter 1 includes a transformer T, a first full-bridge circuit B1, a first inductor L1, a first capacitor C1, a second full-bridge circuit B2, a second inductor L2, a second capacitor C2, two input-output terminals TI, two input-output terminals TO, a control unit 11, a third voltage detection unit DV3, a third current detection unit DC3, and a fourth voltage detection unit DV4. In addition, Figure 6 In order to prevent the figure from becoming complicated, a transmission path connecting the control unit 11 and other circuits in the DAB converter 1 is not depicted.

[0115] in addition, Figure 6 In the example shown, the load LD is not connected to the DAB converter 1. In addition, in this example, two DC power supplies not shown are connected to the DAB converter 1. More specifically, in this example, a first DC power supply not shown is connected to the input / output terminal TI1 and the input / output terminal TI2 of the DAB converter 1. In addition, in this example, a second DC power supply not shown is connected to the input / output terminal TO1 and the input / output terminal TO2 of the DAB converter 1.

[0116] The third voltage detection unit DV3 is a voltage detection circuit. The third voltage detection unit DV3 is connected between the midpoint P11 and the midpoint P12. Thus, the third voltage detection unit DV3 can detect the voltage applied to both ends of the first part PT1 as the third voltage. In addition, the third voltage detection unit DV3 is connected to the control unit 11 via a transmission path not shown in the figure. That is, the control unit 11 detects the third voltage via the third voltage detection unit DV3. In addition, the third voltage detection unit DV3 can also be a structure connected between the input-output terminal P13 and the input-output terminal P14, and the voltage applied between the input-output terminal P13 and the input-output terminal P14 is detected as the third voltage. In addition, in this case, the third voltage detection unit DV3, like the first voltage detection unit DV1, can also be a structure installed from the outside on the DAB converter 1.

[0117] The third current detection unit DC3 is a current detection circuit. The third current detection unit DC3 is connected between the midpoint P11 and the first part PT1. Thus, the third current detection unit DC3 can detect the current flowing through the first part PT1 as the third current. In addition, the third current detection unit DC3 is connected to the control unit 11 via a transmission path not shown in the figure. That is, the control unit 11 detects the third current via the third current detection unit DC3.

[0118] The fourth voltage detection unit DV4 is a voltage detection circuit. The fourth voltage detection unit DV4 is connected between the midpoint P21 and the midpoint P22. Thus, the fourth voltage detection unit DV4 can detect the voltage applied to both ends of the second part PT2 as the fourth voltage. In addition, the fourth voltage detection unit DV4 is connected to the control unit 11 via a transmission path not shown in the figure. That is, the control unit 11 detects the fourth voltage via the fourth voltage detection unit DV4. In addition, the fourth voltage detection unit DV4 can also be a structure connected between the input-output terminal P23 and the input-output terminal P24, and the voltage applied between the input-output terminal P23 and the input-output terminal P24 is detected as the fourth voltage. In addition, in this case, the fourth voltage detection unit DV4, like the second voltage detection unit DV2, can also be a structure installed from the outside on the DAB converter 1.

[0119] Here, Figure 7 yes Figure 6 The DAB converter 1 shown is an equivalent circuit of a portion including a first portion PT1 and a second portion PT2. Figure 7 The inductor SL1 shown represents Figure 7 An example of the inductance of the first part PT1 in the equivalent circuit shown. Figure 7 The inductor SL2 shown represents Figure 7 An example of the inductance of the second part PT2 in the equivalent circuit shown. Figure 7 The inductance Lm shown is Figure 7 An example of the mutual inductance of the transformer T in the equivalent circuit shown. Figure 7 The voltage VL shown indicates Figure 7 An example of the voltage applied between the midpoint P11 and the midpoint P21 in the equivalent circuit shown. Figure 7 The voltage VI1 shown indicates Figure 7 An example of the voltage applied between the midpoint P11 and the midpoint P12 in the equivalent circuit shown. Figure 7 The voltage VI2 shown indicates Figure 7 An example of a voltage applied between the midpoint P21 and the midpoint P22 in the equivalent circuit shown. Figure 7 The current It1 shown represents Figure 7 This is an example of a current flowing from the midpoint P11 to the midpoint P21 in the equivalent circuit shown.

[0120] Here, when v1 represents the magnitude of the voltage applied from the first DC power supply to the two input-output terminals TI of the DAB converter 1, v2 represents the magnitude of the voltage applied from the first DC power supply to the two input-output terminals TI of the DAB converter 1, l1 represents the combined inductance of the inductance of the first inductor L1 and the leakage inductance of the primary side winding T1, and l2 represents the combined inductance of the inductance of the second inductor L2 and the leakage inductance of the secondary side winding T2, each of the inductance SL1, the inductance SL2, the voltage VI1, and the voltage VI2 can be expressed as shown in the following equations (3) to (6).

[0121] SL1=l1……(3)

[0122] SL2=l2×(N2 / N1) 2 ……(4)

[0123] VI1=v1……(5)

[0124] VI2=v2×(N2 / N1)……(6)

[0125] In this case, by supplying voltages from the first DC power supply and the second DC power supply to the DAB converter 1 , the control unit 11 can estimate the estimated value by the method described below.

[0126] Here, Figure 8 This is a diagram for explaining processing performed by the control unit 11 when estimating an estimated value in a modification of the embodiment.

[0127] When estimating the estimated value in the modified example of the embodiment, the control unit 11 makes the state of the switching element S11 as follows: Figure 8 As shown in the graph TL51 shown, the state repeatedly changes between the on state and the off state. Figure 8 The graph TL51 shown is a graph showing an example of the temporal change in the state of the switching element S11 in this case. In the graph TL51, the period when the state of the switching element S11 is in the on state is represented by the period when the displacement of the square wave shown in the graph TL51 coincides with "ON". In addition, in the graph TL51, the period when the state of the switching element S11 is in the off state is represented by the period when the displacement of the square wave shown in the graph TL51 coincides with "OFF". In addition, since the square wave representing the temporal change in the state of the switching element S12 is a square wave whose phase is offset by 2π from the square wave representing the temporal change in the state of the switching element S11, it is omitted from the diagram.

[0128] In addition, when estimating the estimated value in the modified example of the embodiment, the control unit 11 makes the state of the switching element S13 as follows: Figure 8As shown in the graph TL53 shown, the state repeatedly changes between the on state and the off state. Figure 8 The graph TL53 shown is a graph showing an example of the temporal change in the state of the switching element S13 in this case. In the graph TL53, the period when the state of the switching element S13 is in the on state is represented by the period when the displacement of the square wave shown in the graph TL53 coincides with "ON". In addition, in the graph TL53, the period when the state of the switching element S13 is in the off state is represented by the period when the displacement of the square wave shown in the graph TL53 coincides with "OFF". In addition, since the square wave representing the temporal change in the state of the switching element S14 is a square wave whose phase is offset by 2π from the square wave representing the temporal change in the state of the switching element S13, it is omitted from the diagram.

[0129] In addition, when estimating the estimated value in the modified example of the embodiment, the control unit 11 makes the state of the switching element S21 as follows: Figure 8 As shown in the graph TL61 shown, the state repeatedly changes between the on state and the off state. Figure 8 The graph TL61 shown is a graph showing an example of the temporal change in the state of the switching element S21 in this case. In the graph TL61, the period during which the state of the switching element S21 is in the on state is represented by the period during which the displacement of the square wave shown in the graph TL61 coincides with "ON". In addition, in the graph TL61, the period during which the state of the switching element S21 is in the off state is represented by the period during which the displacement of the square wave shown in the graph TL61 coincides with "OFF". In addition, since the square wave representing the temporal change in the state of the switching element S22 is a square wave whose phase is offset by 2π from the square wave representing the temporal change in the state of the switching element S21, it is omitted from the diagram.

[0130] In addition, when the estimated value is estimated in the modified example of the embodiment, the control unit 11 sets the state of the switch element S23 as follows: Figure 8 As shown in the graph TL63 shown, the state repeatedly changes between the on state and the off state. Figure 8 The graph TL63 shown is a graph showing an example of the temporal change in the state of the switching element S23 in this case. In the graph TL63, the period during which the state of the switching element S23 is in the on state is represented by the period during which the displacement of the square wave shown in the graph TL63 coincides with "ON". In addition, in the graph TL63, the period during which the state of the switching element S23 is in the off state is represented by the period during which the displacement of the square wave shown in the graph TL63 coincides with "OFF". In addition, since the square wave representing the temporal change in the state of the switching element S24 is a square wave whose phase is offset by 2π from the square wave representing the temporal change in the state of the switching element S23, it is omitted from the diagram.

[0131] When each of the switching elements S11 to S14 and each of the switching elements S21 to S24 are connected as Figure 8 When switching is performed as shown, the voltage VI1 is as follows Figure 8 The graph DL5 shown in FIG. 5 changes with time.

[0132] In addition, when each of the switching elements S11 to S14 and each of the switching elements S21 to S24 are connected as shown in FIG. Figure 8 When switching is performed as shown, the voltage VI2 is as follows Figure 8 The graph DL6 shown in FIG.

[0133] Based on these, each of the switching elements S11 to S14 and each of the switching elements S21 to S24 are as follows: Figure 8 When switching is performed as shown, the voltage VL is Figure 8 The graph DL7 shown in FIG. Figure 8 As shown, VL is determined according to the difference between VI1 and VI2, that is, the difference between the third voltage and the fourth voltage.

[0134] Here, as shown in graphs DL5 to DL7 , the temporal changes of voltage VI1 , voltage VI2 , and voltage VL become square waves synchronized with the switching of switching elements S11 to S14 and S21 to S24 .

[0135] On the other hand, when each of the switching elements S11 to S14 and each of the switching elements S21 to S24 are connected as shown in FIG. Figure 8 When switching is performed as shown, the current It1 is as follows Figure 8 As shown in the graph IL1, the temporal change of the current It1 in this case is a periodic increase with a certain slope and a decrease with a certain slope. Here, the time t1 and the time t2 are two different times in one of the multiple periods in which the current It1 increases with a certain slope. Moreover, the time t2 is a time later than the time t1. In the following, for the convenience of explanation, the current value of the current It1 at the time t1 is represented by i1, and the current value of the current It1 at the time t2 is represented by i2 and explained.

[0136] Here, the control unit 11 can estimate the estimated value based on the voltage VL, the current value i1, the current value i2, the time t1, the time t2, and the following formula (7).

[0137] Lp=VL(t2-t1) / (i2-i1)……(7)

[0138] In addition, Lp shown in the above-mentioned formula (7) represents an estimated value observed from the first full-bridge circuit B1. The above-mentioned formula (7) can be derived by immediate calculation based on electromagnetism. Therefore, the description of the derivation method of formula (7) is omitted.

[0139] That is, the control unit 11 can estimate the estimated value viewed from the first full-bridge circuit B1 based on the difference between the third voltage and the fourth voltage, the third current, and the above-mentioned equation (7).

[0140] Here, even if the control unit 11 short-circuits the secondary side circuit of the DAB converter 1, that is, even if the second full-bridge circuit B2 is short-circuited, it is possible to estimate the estimated value observed from the first full-bridge circuit B1 based on the difference between the third voltage and the fourth voltage, the third current, and the above-mentioned formula (7). For example, the control unit 11 can short-circuit the secondary side circuit of the DAB converter 1 by setting the states of both the switch element S21 and the switch element S23 to the on state, or by setting the states of both the switch element S22 and the switch element S24 to the on state. In this case, Figure 7 The equivalent circuit shown is Fig. 9 The equivalent circuit shown in FIG. Fig. 9 It is an equivalent circuit of the portion of the DAB converter 1 including the first portion PT1 and the second portion PT2 when the secondary side circuit is short-circuited. In this case, the control unit 11 can also estimate the estimated value observed from the first full-bridge circuit B1 based on the difference between the third voltage and the fourth voltage, the third current, and the above-mentioned formula (7). In addition, in this case, the generation of the excitation current in the transformer T can be suppressed, so the inductance (that is, the estimated value) can be estimated more accurately. As a result, the DAB converter 1 can more reliably suppress the reduction in the power transmission efficiency due to the individual difference in the inductance.

[0141] Furthermore, the DAB converter 1 may be configured to include a fourth current detection unit DC4 instead of or in addition to the third current detection unit DC3 .

[0142] The fourth current detection unit DC4 is a current detection circuit. The fourth current detection unit DC4 is connected between the midpoint P21 and the second part PT2. Thus, the fourth current detection unit DC4 can detect the current flowing through the second part PT2 as the fourth current. In addition, the fourth current detection unit DC4 is connected to the control unit 11 via a transmission path not shown in the figure. That is, the control unit 11 detects the fourth current via the fourth current detection unit DC4.

[0143] When the DAB converter 1 includes the fourth current detection unit DC4, the control unit 11 can estimate the estimated value observed from the second full-bridge circuit B2 instead of the estimated value observed from the first full-bridge circuit B1. In this case, the DAB converter 1 can also suppress the reduction in power transmission efficiency due to individual differences in inductance. In this case, since the details of the formula used by the control unit 11 in the estimation instead of formula (7) can be easily derived from electromagnetism, the description is omitted.

[0144] Furthermore, the method of estimating the estimated value and the method of adjusting the phase difference based on the estimated value described above can also be applied to other electronic devices instead of the DAB converter.

[0145] As described above, the DAB converter of the embodiment (in the example described above, the DAB converter 1) includes: a transformer (in the example described above, the transformer T) having a primary winding (in the example described above, the primary winding T1) and a secondary winding (in the example described above, the secondary winding T2), a first full bridge circuit (in the example described above, the first full bridge circuit B1), a second full bridge circuit (in the example described above, the second full bridge circuit B2), a first capacitor (in the example described above, the first capacitor C1), a second capacitor (in the example described above, the second capacitor C2), and a control unit (in the example described above, the control unit 11) for controlling switches of the first full bridge circuit and switches of the second full bridge circuit. In the DAB converter, the eleventh midpoint (in the example described above, the midpoint P11) of the two midpoints of the first full bridge circuit is A primary winding is connected between the twelfth midpoint of the two midpoints of the first full-bridge circuit (midpoint P12 in the example described above), a secondary winding is connected between the twenty-first midpoint of the two midpoints of the second full-bridge circuit (midpoint P21 in the example described above) and the twenty-second midpoint of the two midpoints of the second full-bridge circuit (midpoint P22 in the example described above), a first capacitor is connected between two input / output terminals of the first full-bridge circuit (input / output terminal P13 and input / output terminal P14 in the example described above), and a second capacitor is connected between two input / output terminals of the second full-bridge circuit (input / output terminal P23 and input / output terminal P24 in the example described above), and the control unit adjusts the phase difference between the switch of the first full-bridge circuit and the switch of the second full-bridge circuit based on the estimated value of the inductance of the DAB converter. Thus, the DAB converter can suppress the reduction of power transmission efficiency due to individual differences in inductance.

[0146] In addition, a DAB converter may have a structure in which the inductance of the DAB converter is a combined inductance of the leakage inductance of the primary-side winding and the leakage inductance of the secondary-side winding.

[0147] In addition, the DAB converter can also use the following structure, which also includes a first inductor (in the example described above, the first inductor L1), and the primary side winding and the first inductor are connected in series between the eleventh midpoint and the twelfth midpoint. The inductance of the DAB converter is the combined inductance of the leakage inductance of the primary side winding, the leakage inductance of the secondary side winding, and the inductance of the first inductor.

[0148] In addition, the DAB converter can also use the following structure, which also includes a second inductor (in the example described above, the second inductor L2), and the secondary side winding and the second inductor are connected in series between the 21st midpoint and the above-mentioned 22nd midpoint, and the inductance of the DAB converter is the combined inductance of the leakage inductance of the primary side winding, the leakage inductance of the secondary side winding, and the inductance of the second inductor.

[0149] In addition, the DAB converter may also use the following structure, further comprising a first inductor and a second inductor, wherein the primary side winding and the first inductor are connected in series between the eleventh midpoint and the twelfth midpoint, and the secondary side winding and the second inductor are connected in series between the twenty-first midpoint and the twenty-second midpoint, and the inductance of the DAB converter is a combined inductance of the leakage inductance of the primary side winding, the leakage inductance of the secondary side winding, the inductance of the first inductor, and the inductance of the second inductor.

[0150] In addition, the following structure can also be used in the DAB converter, wherein the estimated value is a value estimated based on a first voltage applied between two input-output terminals of a first full-bridge circuit, a first current flowing through one of the two input-output terminals of the first full-bridge circuit, and a second voltage applied between two input-output terminals of a second full-bridge circuit.

[0151] In addition, the following structure can also be used in the DAB converter, wherein the estimated value is a value estimated based on a first voltage applied between two input-output terminals of the first full-bridge circuit, a second voltage applied between two input-output terminals of the second full-bridge circuit, and a second current flowing through one of the two input-output terminals of the second full-bridge circuit.

[0152] In addition, the following structure can also be used in the DAB converter, in which the estimated value is estimated based on a third voltage applied to both ends of a first part including a primary side winding (in the example described above, the first part P1), a third current flowing through the first part, and a fourth voltage applied to both ends of a second part including a secondary side winding (in the example described above, the second part PT2).

[0153] In addition, the following structure can also be used in the DAB converter, wherein the estimated value is estimated based on a third voltage applied to both ends of a first portion including a primary side winding, a fourth voltage applied to both ends of a second portion including a secondary side winding, and a fourth current flowing through the second portion.

[0154] In addition, the following structure can also be used in the DAB converter, wherein the estimated value is estimated based on a third voltage applied to both ends of a first part including a first inductor and a primary side winding, a third current flowing through the first inductor, and a fourth voltage applied to both ends of a second part including a secondary side winding.

[0155] In addition, the DAB converter may have a configuration in which the estimated value is an estimated value observed from the first full-bridge circuit and is a value estimated based on the difference between the third voltage and the fourth voltage and the third current.

[0156] In addition, the following structure can also be used in the DAB converter, wherein the estimated value is a value estimated by a third voltage applied to both ends of a first part including a primary side winding, a fourth voltage applied to both ends of a second part including a second inductor and the above-mentioned secondary side winding, and a fourth current flowing through the second part.

[0157] In addition, the DAB converter may have a configuration in which the estimated value is an estimated value observed from the second full-bridge circuit and is a value estimated based on the difference between the third voltage and the fourth voltage and the fourth current.

[0158] In addition, the DAB converter may also be configured such that the control unit acquires the estimated value and adjusts the phase difference based on the acquired estimated value.

[0159] In addition, the DAB converter may also adopt a configuration in which the control unit estimates the estimated value and adjusts the phase difference based on the estimated value.

[0160] In addition, the DAB converter may also have a configuration in which the control unit adjusts the phase difference by adjusting one or both of the switches of the first full-bridge circuit and the switches of the second full-bridge circuit.

[0161] In addition, the following structure can also be used in the DAB converter, wherein the control unit specifically represents phase difference information corresponding to the estimated value, and adjusts the phase difference based on the specific phase difference information, and the phase difference information includes information for adjusting either or both of the switches of the first full-bridge circuit and the switches of the second full-bridge circuit.

[0162] Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments and changes, substitutions, deletions, etc. may be made without departing from the spirit of the present invention.

Claims

1. A DAB converter, wherein: The DAB converter is a dual active bridge converter having: A transformer having a primary winding and a secondary winding; A first full bridge circuit; A second full bridge circuit; a first capacitor; a second capacitor; a control unit that controls a switch of the first full-bridge circuit and a switch of the second full-bridge circuit; a first voltage detection unit; a second voltage detection unit; as well as a first current detection unit, The primary side winding is connected between an eleventh midpoint of the two midpoints of the first full-bridge circuit and a twelfth midpoint of the two midpoints of the first full-bridge circuit. The secondary winding is connected between a twenty-first midpoint of the two midpoints of the second full-bridge circuit and a twenty-second midpoint of the two midpoints of the second full-bridge circuit. The first capacitor is connected between two input and output terminals of the first full-bridge circuit. The second capacitor is connected between two input and output terminals of the second full-bridge circuit. The first voltage detection unit detects a first voltage between the eleventh midpoint and the twelfth midpoint, The second voltage detection unit detects a second voltage between the 21st midpoint and the 22nd midpoint, The first current detection unit detects a first current flowing between the eleventh midpoint and the primary winding. The control unit, When operating in an adjustment mode for adjusting the phase difference between the switches of the first full-bridge circuit and the switches of the second full-bridge circuit, by applying voltages between two input / output terminals of the first full-bridge circuit and between two input / output terminals of the second full-bridge circuit, an estimated value of the inductance of the DAB converter is estimated based on the first voltage detected by the first voltage detection unit, the second voltage detected by the second voltage detection unit, the first current detected by the first current detection unit, the number of turns of the primary winding, the number of turns of the secondary winding, the phase difference between the switches of the first full-bridge circuit and the switches of the second full-bridge circuit, and the angular frequency between the switches of the first full-bridge circuit and the switches of the second full-bridge circuit, When operating in the normal operation mode, adjusting the phase difference between the switches of the first full-bridge circuit and the switches of the second full-bridge circuit based on the estimated value of the inductance of the DAB converter estimated when operating in the adjustment mode, The inductance of the DAB converter is a composite inductance of the inductance of the primary side circuit of the DAB converter and the inductance of the secondary side circuit of the DAB converter. The inductance of the primary side circuit of the DAB converter is the inductance of the portion connected between the eleventh midpoint and the twelfth midpoint. The inductance of the secondary side circuit of the DAB converter is the inductance of a portion connected between the 21st midpoint and the 22nd midpoint.

2. The DAB converter according to claim 1, wherein: The inductance of the DAB converter is a composite inductance of the leakage inductance of the primary side winding and the leakage inductance of the secondary side winding.

3. The DAB converter according to claim 1, wherein: further comprising a first inductor, The primary side winding and the first inductor are connected in series between the eleventh midpoint and the twelfth midpoint. The inductance of the DAB converter is a composite inductance of the leakage inductance of the primary side winding, the leakage inductance of the secondary side winding, and the inductance of the first inductor.

4. The DAB converter according to claim 1, wherein: Also having a second inductor, The secondary side winding and the second inductor are connected in series between the 21st midpoint and the 22nd midpoint. The inductance of the DAB converter is a composite inductance of the leakage inductance of the primary side winding, the leakage inductance of the secondary side winding, and the inductance of the second inductor.

5. The DAB converter according to claim 1, wherein: Also available: a first inductor; as well as The second inductor, The primary side winding and the first inductor are connected in series between the eleventh midpoint and the twelfth midpoint. The secondary side winding and the second inductor are connected in series between the 21st midpoint and the 22nd midpoint. The inductance of the DAB converter is a composite inductance of a leakage inductance of the primary side winding, a leakage inductance of the secondary side winding, an inductance of the first inductor, and an inductance of the second inductor.

6. The DAB converter according to any one of claims 1 to 5, wherein: The control unit adjusts the phase difference by adjusting one or both of the switches of the first full-bridge circuit and the switches of the second full-bridge circuit.

7. The DAB converter according to any one of claims 1 to 5, wherein: The control unit acquires phase difference information indicating the phase difference corresponding to the estimated value of the inductance of the DAB converter, and adjusts the phase difference based on the acquired phase difference information. The phase difference information includes information for adjusting one or both of the switches of the first full-bridge circuit and the switches of the second full-bridge circuit.

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