Power supply device

Abstract

To attain downsizing and reduction of cost while suppressing a surge voltage.SOLUTION: A power supply device includes: a power receiving coil which receives power generated by a power transmitting coil and outputs an induced AC voltage; a capacitor with one end electrically connected to a high potential side of the power receiving coil and the other end electrically connected to a low potential side of the power receiving coil; a rectifier circuit which includes a first diode, a second diode, a third diode and a fourth diode and performs full-wave rectification upon the AC voltage outputted from the power receiving coil; an inductor with one end electrically connected to a low potential side of the capacitor and the other end electrically connected to an anode of the second diode and a cathode of the fourth diode; a switch which is connected to the third diode in parallel; a half-wave rectifier circuit with one end electrically connected to the low potential side of the power receiving coil and the other end electrically connected to an anode of the third diode and an anode of the fourth diode; and a control section which controls the switch and the half-wave rectifier circuit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a power supply device. [Background technology]

[0002] Patent Document 1 describes a power supply circuit that can suppress overvoltage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-141756 A Summary of the Invention [Problem to be solved by the invention]

[0004] As a power supply system for charging a vehicle battery, a system is known in which a power receiving device provided in the vehicle receives power output from a power transmitting device provided on the ground or the like and charges the vehicle battery. Such a power supply system is provided with a protection circuit to protect the vehicle battery from overvoltage. However, when a protection operation by the protection circuit is performed, the surge voltage applied to the power transmitting device and the power receiving device may become high. In order to protect the power transmitting device and the power receiving device from the surge voltage, it is necessary to increase the withstand voltage of each capacitor and to increase the creepage distance of each coil, which may result in an increase in the size and cost of the device.

[0005] The present disclosure aims to reduce size and cost while suppressing surge voltage. [Means for solving the problem]

[0006] The power supply device of the present disclosure includes a receiving coil that receives power generated by a transmitting coil of a power transmitting device and outputs an induced AC voltage, a capacitor having one end electrically connected to the high potential side of the receiving coil and the other end electrically connected to the low potential side of the receiving coil, a rectifier circuit that includes at least a first diode and a second diode provided on the high side and a third diode and a fourth diode provided on the low side, and that full-wave rectifies the AC voltage output from the receiving coil and outputs the full-wave rectified voltage, an inductor having one end electrically connected to the low potential side of the capacitor and the other end electrically connected to the anode of the second diode and the cathode of the fourth diode, a switch connected in parallel to the third diode, a half-wave rectifier circuit having one end electrically connected to the low potential side of the receiving coil and the other end electrically connected to the anode of the third diode and the anode of the fourth diode, and a control unit that controls the switch and the half-wave rectifier circuit.

[0007] In the power supply device of the present disclosure, the rectifier circuit is a bridge diode.

[0008] In the power supply device of the present disclosure, the half-wave rectifier circuit includes a fifth diode and a switch element, the fifth diode having an anode electrically connected between the low potential side of the receiving coil and the low potential side of the capacitor and a cathode electrically connected to the drain of the switch element, and the switch element having a source electrically connected to the anode of the third diode and the anode of the fourth diode.

[0009] In the power supply device of the present disclosure, the control unit controls the switch and the switch element to be on when an overvoltage occurs. Effect of the Invention

[0010] According to the present disclosure, it is possible to reduce the size and cost while suppressing surge voltage. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a power supply system according to a comparative example. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of the power supply system according to the embodiment. [Diagram 3] FIG. 3 is a diagram for explaining a path of a current flowing in the power transmitting device in a normal state according to the embodiment. [Figure 4] FIG. 4 is a diagram for explaining a path of a current flowing in the power transmitting device during a protective operation against an overvoltage according to the embodiment. [Diagram 5] FIG. 5 is a diagram showing a simulated waveform of a surge voltage generated in a power transmitting coil during a protective operation against an overvoltage according to a comparative example. [Figure 6] FIG. 6 is a diagram showing a simulation waveform of a surge voltage generated in a power transmitting coil during a protective operation against an overvoltage according to the embodiment. [Figure 7] FIG. 7 is a diagram showing a simulated waveform of a surge voltage generated in a capacitor during a protective operation against an overvoltage according to the comparative example. [Figure 8] FIG. 8 is a diagram showing a simulation waveform of a surge voltage generated in a capacitor during a protection operation against an overvoltage according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to this embodiment, and in the following embodiments, the same components are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0013] [Comparative Example] Before describing an embodiment of the present disclosure, a comparative example of the present disclosure will be described. Fig. 1 is a diagram showing a configuration example of a power supply system according to the comparative example.

[0014] As shown in Fig. 1, a power supply system 1000a according to the comparative example includes a power transmission device 1, a power receiving device 2a, and a control unit 3a. The power transmission device 1 is provided on the ground, such as a road on which a vehicle runs. The power receiving device 2a is provided in the vehicle. The power supply system 1000a is a non-contact power supply system capable of charging a battery of the vehicle by receiving power output by the power transmission device 1 with the power receiving device 2a.

[0015] (Power transmission equipment) As shown in FIG. 1, the power transmitting device 1 includes a transistor 11, a transistor 12, a transistor 13, a transistor 14, an inductor 15, an inductor 16, a capacitor 17, a capacitor 18, a capacitor 19, and a power transmitting coil 20.

[0016] The transistor 11 is provided on the high side. The drain of the transistor 11 is electrically connected to a first input terminal 1a. The first input terminal 1a is electrically connected to a high potential side terminal of a power supply (not shown). The source of the transistor 11 is electrically connected to one end of an inductor 15 provided on the high side.

[0017] The transistor 12 is provided on the low side. The drain of the transistor 12 is electrically connected to the source of the transistor 11 and one end of the inductor 15. The source of the transistor 12 is electrically connected to a second input terminal 1b. The second input terminal 1b is electrically connected to a low potential side terminal of a power supply (not shown).

[0018] The transistor 13 is provided on the high side. The drain of the transistor 13 is electrically connected to the first input terminal 1a. The source of the transistor 13 is electrically connected to one end of the inductor 16 provided on the low side.

[0019] The transistor 14 is provided on the low side. The drain of the transistor 14 is electrically connected to the source of the transistor 13 and one end of the inductor 16. The source of the transistor 14 is electrically connected to the second input terminal 1b.

[0020] In the present disclosure, each transistor is described as being a MOSFET, but is not limited to this, and each transistor may be a silicon power device, a GaN power device, a SiC power device, etc.

[0021] The other end of the inductor 15 is electrically connected to one end of the capacitor 17. The other end of the inductor 16 is electrically connected to the other end of the capacitor 17.

[0022] The capacitor 18 is provided on the high side. One end of the capacitor 18 is electrically connected to the other end of the inductor 15 and one end of the capacitor 17. The other end of the capacitor 18 is electrically connected to the high potential side terminal of the power transmitting coil 20.

[0023] The capacitor 19 is provided on the low side. One end of the capacitor 19 is electrically connected to the other end of the inductor 16 and the other end of the capacitor 17. The other end of the capacitor 19 is electrically connected to the low potential side terminal of the power transmitting coil 20.

[0024] The power transmitting coil 20 is configured to transmit electric power to a power receiving coil 21 of the power receiving device 2 .

[0025] (Power receiving device) As shown in FIG. 1, the power receiving device 2a includes a power receiving coil 21, a capacitor 22, a capacitor 23, a capacitor 24, an inductor 25, an inductor 26, a diode 27, a diode 28, a diode 29, a diode 30, a switch 31, a switch 32, a capacitor 33, a capacitor 34, a capacitor 35, and a battery 36.

[0026] A high-potential terminal of the power receiving coil 21 is electrically connected to one end of a capacitor 22 provided on the high side. A low-potential terminal of the power receiving coil 21 is electrically connected to one end of a capacitor 23 provided on the low side. The power receiving coil 21 is configured to receive power transmitted from the power transmitting coil 20 of the power transmitting device 1 and output an AC voltage.

[0027] The other end of the capacitor 22 is electrically connected to one end of the capacitor 24. The other end of the capacitor 23 is electrically connected to the other end of the capacitor 24.

[0028] The inductor 25 is provided on the high side. One end of the inductor 25 is electrically connected to the other end of the capacitor 22 and one end of the capacitor 24.

[0029] The inductor 26 is provided on the low side. One end of the inductor 26 is electrically connected to the other end of the capacitor 23 and the other end of the capacitor 24.

[0030] The diode 27 is provided on the high side. The anode of the diode 27 is electrically connected to the other end of the inductor 25. The cathode of the diode 27 is electrically connected to the high potential side terminal of the battery 36. The diode 27 is also called a first diode.

[0031] The diode 28 is provided on the low side. The anode of the diode 28 is electrically connected to the low potential side terminal of the battery 36. The cathode of the diode 28 is electrically connected to the other end of the inductor 25 and the anode of the diode 27. The diode 28 is also called a third diode.

[0032] The diode 29 is provided on the high side. The anode of the diode 29 is electrically connected to the other end of the inductor 26. The cathode of the diode 29 is electrically connected to the high potential side terminal of the battery 36. The diode 29 is also called a second diode.

[0033] The diode 30 is provided on the low side. The anode of the diode 30 is electrically connected to the low potential side terminal of the battery 36. The cathode of the diode 30 is electrically connected to the other end of the inductor 26 and the anode of the diode 29. The diode 30 is also called a fourth diode.

[0034] The diodes 27, 28, 29, and 30 form a bridge diode. The diodes 27, 28, 29, and 30 form a rectifier circuit that full-wave rectifies the AC voltage output from the power receiving coil 21 and outputs the full-wave rectified voltage.

[0035] The switch 31 is provided on the low side. One end of the switch 31 is electrically connected to the cathode of the diode 28. The other end of the switch 31 is electrically connected to the anode of the diode 28. In other words, the switch 31 is connected in parallel to the diode 28. When the switch 31 is on, it shorts the anode and cathode of the diode 28.

[0036] The switch 32 is provided on the low side. One end of the switch 32 is electrically connected to the cathode of the diode 30. The other end of the switch 32 is electrically connected to the anode of the diode 30. In other words, the switch 32 is connected in parallel with the diode 30. When the switch 32 is on, it shorts the anode and cathode of the diode 30.

[0037] The switches 31 and 32 are, for example, field effect transistors (FETs) or insulated gate bipolar transistors (IGBTs), but are not limited to these.

[0038] The capacitor 33 is provided on the high side. One end of the capacitor 33 is electrically connected to the high potential side of the battery 36. The other end of the capacitor 33 is electrically connected to the other end of the inductor 26, the anode of the diode 29, and the cathode of the diode 30.

[0039] The capacitor 34 is provided on the low side. One end of the capacitor 34 is electrically connected to the other end of the inductor 26, the anode of the diode 29, the cathode of the diode 30, and the other end of the capacitor 33. The other end of the capacitor 34 is electrically connected to the low potential side of the battery 36.

[0040] One end of the capacitor 35 is electrically connected to a high potential terminal of the battery 36. The other end of the capacitor 35 is electrically connected to a low potential terminal of the battery 36. The capacitor 35 smoothes the voltages output from the diodes 27, 28, 29, and 30.

[0041] (Control unit) The control unit 3a controls the power receiving device 2a. The control unit 3a includes, for example, an information processing device such as a DSP (Digital Signal Processor), a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory).

[0042] The control unit 3a outputs a control signal to the power receiving device 2a and controls the on and off of the switch 31 and the switch 32. The control unit 3a normally controls the switch 31 and the switch 32 to be off. When an overvoltage occurs, the control unit 3a controls the switch 31 and the switch 32 to be on. By turning on the switch 31 and the transistor 42, the battery 36 can be protected from the overvoltage.

[0043] In the comparative example, when an overvoltage occurs, the switch 31 and the switch 32 are shorted to protect the battery 36 from the overvoltage. However, when the switch 31 and the switch 32 are shorted, the surge voltage applied to the capacitor 18, the transmitting coil 20, the receiving coil 21, the capacitor 22, and the capacitor 23 increases. Therefore, in the comparative example, it is necessary to increase the withstand voltage of each capacitor and to increase the creepage distance of each coil, which may result in an increase in size and cost. Therefore, the present disclosure configures a power supply system that can be made smaller and less expensive while suppressing the surge voltage.

[0044] [Embodiment] An embodiment of the present disclosure will be described. Fig. 2 is a diagram showing a configuration example of a power supply system according to an embodiment. Among the components of the embodiment, the same components as those of the comparative example are given the same reference numerals and the description thereof will be omitted.

[0045] As shown in FIG. 2, a power supply system 1000 according to the embodiment includes a power transmitting device 1, a power receiving device 2, and a control unit 3.

[0046] (Power receiving device) The power receiving device 2 includes a power receiving coil 21, a capacitor 22, a capacitor 23, a capacitor 24, an inductor 25, an inductor 26, a diode 27, a diode 28, a diode 29, a diode 30, a switch 31, a capacitor 33, a capacitor 34, a capacitor 35, a battery 36, and a half-wave rectifier circuit 40. The power receiving device 2 differs from the power receiving device 2a shown in FIG. 1 in that the power receiving device 2 does not include the switch 31 and includes the half-wave rectifier circuit 40.

[0047] The half-wave rectifier circuit 40 is provided on the low side. One end of the half-wave rectifier circuit 40 is electrically connected to the low potential side of the power receiving coil 21. The other end of the half-wave rectifier circuit 40 is electrically connected to the anode of the diode 28 and the anode of the diode 30. The half-wave rectifier circuit 40 includes a diode 41 and a transistor 42. The diode 41 is a type of fifth diode. The transistor 42 is a type of switch element.

[0048] The anode of the diode 41 is electrically connected to the other end of the capacitor 23, the other end of the capacitor 24, and one end of the inductor 26. The cathode of the diode 41 is electrically connected to the drain of the transistor 42. The diode 41 is a half-wave rectifier diode. The diode 41 prevents reverse flow of current that has passed through the body diode of the transistor 42.

[0049] The source of transistor 42 is electrically connected to the anode of diode 28 and the anode of diode 30 .

[0050] The transistor 42 has a parasitic diode (body diode) that can actively conduct current or is connected in anti-parallel to a diode 43. A parasitic diode is a pn junction between the backgate and the source and drain of a MOSFET.

[0051] (Control unit) The control unit 3 controls the power receiving device 2. The control unit 3 includes, for example, an information processing device such as a DSP, a CPU, or an MPU, and a storage device such as a RAM or a ROM.

[0052] The control unit 3 outputs a control signal to the power receiving device 2 and controls the on and off of the switch 31 and the transistor 42. The control unit 3 normally controls the switch 31 and the transistor 42 to be off. When an overvoltage occurs, the control unit 3 controls the switch 31 and the transistor 42 to be on. By turning on the switch 31 and the transistor 42, the battery 36 can be protected from the overvoltage.

[0053] (Normal current path) 3 is a diagram for explaining a path of a current flowing in a power transmission device in a normal state according to the embodiment. In a normal state, the switch 31 and the transistor 42 are off. In this case, as indicated by an arrow 101, the current flows in the order of the capacitor 22 → the inductor 25 → the diode 27 → the capacitor 35 → the diode 30 → the inductor 26 → the capacitor 23. Also, as indicated by an arrow 102, the current flows in the order of the capacitor 23 → the inductor 26 → the diode 29 → the capacitor 35 → the diode 28 → the inductor 25 → the capacitor 22.

[0054] (Current path during overvoltage protection) FIG. 4 is a diagram for explaining the path of the current flowing in the power transmission device during the overvoltage protection operation according to the embodiment. During the overvoltage protection operation, the switch 31 and the transistor 42 are on. In this case, as shown by the arrow 103, the current flows in the order of the capacitor 22 → the inductor 25 → the switch 31 → the diode 30 → the inductor 26 → the capacitor 23. Also, as shown by the arrow 104, the current flows in the order of the capacitor 23 → the diode 41 → the transistor 42 → the switch 31 → the inductor 25 → the capacitor 22. That is, during the overvoltage protection operation, in the path shown by the arrow 104, the current flows through a path that shorts the other end of the inductor 25 and the anode of the diode 28, and does not flow through the inductor 26. That is, the current flows in a circular manner so as to avoid the inductor 26. As a result, the embodiment can reduce the voltage applied to the inductor 26, thereby preventing the surge voltage from becoming high.

[0055] (simulation) Circuit simulations were carried out for the power supply system 1000a according to the comparative example shown in FIG. 1 and the power supply system 1000 according to the embodiment shown in FIG.

[0056] (surge voltage of transmission coil) The surge voltage occurring in the power transmission coil will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing a simulated waveform of the surge voltage occurring in the power transmission coil during a protective operation against overvoltage according to a comparative example. Fig. 6 is a diagram showing a simulated waveform of the surge voltage occurring in the power transmission coil during a protective operation against overvoltage according to the embodiment. In Figs. 5 and 6, the horizontal axis indicates time and the vertical axis indicates voltage.

[0057] Fig. 5 shows a simulation result of a surge voltage generated in the power transmitting coil 20 during a protective operation of the power receiving device 2a according to the comparative example. As shown in Fig. 5, during a protective operation of the power receiving device 2a according to the comparative example, a peak-to-peak voltage V1 generated in the power transmitting coil 20 is about 8 kV (kilovolts).

[0058] Fig. 6 shows a simulation waveform of a surge voltage generated in the power transmitting coil 20 during a protection operation of the power receiving device 2 according to the embodiment. As shown in Fig. 6, during a protection operation of the power receiving device 2 according to the embodiment, a peak-to-peak voltage V2 generated in the power transmitting coil 20 is about 4.5 kV. That is, the embodiment can suppress the surge voltage generated in the power transmitting coil 20 by about 3.5 kV compared to the comparative example.

[0059] (capacitor surge voltage) The surge voltage occurring in the capacitor will be described with reference to Fig. 7 and Fig. 8. Fig. 7 is a diagram showing a simulated waveform of the surge voltage occurring in the capacitor during a protective operation against overvoltage according to a comparative example. Fig. 8 is a diagram showing a simulated waveform of the surge voltage occurring in the capacitor during a protective operation against overvoltage according to the embodiment. In Figs. 7 and 8, the horizontal axis indicates time and the vertical axis indicates voltage.

[0060] Fig. 7 shows a simulation result of a surge voltage generated in the capacitor 24 during a protective operation of the power receiving device 2a according to the comparative example. As shown in Fig. 7, during a protective operation of the power receiving device 2a according to the comparative example, a peak-to-peak voltage V3 generated in the capacitor 24 is about 2.5 kV (kilovolts).

[0061] Fig. 8 shows a simulation waveform of a surge voltage generated in the capacitor 24 during a protection operation of the power receiving device 2 according to the embodiment. As shown in Fig. 8, during a protection operation of the power receiving device 2 according to the embodiment, a peak-to-peak voltage V4 generated in the capacitor 24 is about 1.5 kV. That is, the embodiment can suppress the surge voltage generated in the capacitor 24 by about 1.0 kV compared to the comparative example.

[0062] As described above, this embodiment can suppress the surge voltage generated in the power supply system during the protection operation from an overvoltage. As a result, this embodiment does not need to increase the creepage distance of the power transmitting coil and the power receiving coil in the power supply system or use a high-voltage capacitor. Therefore, this embodiment can realize a power supply system that can be made compact and low cost.

[0063] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the contents of these embodiments. The above-mentioned components include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-mentioned components can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the gist of the above-mentioned embodiments. [Explanation of symbols]

[0064] 1 Power transmission equipment 2,2a Power receiving device 3,3a Control section 11, 12, 13, 14, 42 Transistors 15,16,25,26 Inductors 27, 28, 29, 30, 41 Diodes 17,18,19,22,23,24,33,34,35 Capacitors 31,32 Switch 36 Battery 40 Half wave rectifier circuit 1000,1000a power system

Claims

1. a receiving coil that receives power generated by a power transmitting coil of a power transmitting device and outputs an induced AC voltage; a capacitor having one end electrically connected to the high potential side of the receiving coil and the other end electrically connected to the low potential side of the receiving coil; a rectifier circuit including at least a first diode and a second diode provided on a high side and a third diode and a fourth diode provided on a low side, the rectifier circuit full-wave rectifying the AC voltage output from the power receiving coil and outputting the full-wave rectified AC voltage; an inductor having one end electrically connected to the low potential side of the capacitor and the other end electrically connected to the anode of the second diode and the cathode of the fourth diode; a switch connected in parallel with the third diode; a half-wave rectifier circuit having one end electrically connected to a low potential side of the power receiving coil and the other end electrically connected to an anode of the third diode and an anode of the fourth diode; A control unit that controls the switch and the half-wave rectifier circuit; 2. A power supply device comprising:

2. The rectifier circuit is a bridge diode.

2. The power supply device of claim 1.

3. the half-wave rectifier circuit includes a fifth diode and a switch element, the fifth diode has an anode electrically connected between the low potential side of the power receiving coil and the low potential side of the capacitor, and a cathode electrically connected to the drain of the switch element; The switch element has a source electrically connected to the anode of the third diode and the anode of the fourth diode.

3. The power supply device according to claim 1 or 2.

4. The control unit controls the switch and the switch element to be on when an overvoltage occurs.

4. The power supply device of claim 3.

Images