Power supply device

Abstract

To provide a switching power supply device reducing voltage of surge power applied to a switching element and reducing loss.SOLUTION: An insulated switching power supply device 3 has a choke coil L1, switching elements Q5, Q8, Q9, and Q12, current resonance half-bridge circuits 20 and 22, a power factor improving / inverter control circuit 46, and a frequency control circuit 44. The frequency control circuit 44 generates a reference frequency signal fsw with the same frequency as the resonance frequency of the current resonance half-bridge circuits 20 and 22. The power factor improving / inverter control circuit 46 controls switching elements included in the current resonance half-bridge circuits 20 and 22, supplies power of a power supply Vi to a load Lo, and conversely regenerates power from a battery BAT to the power supply Vi.SELECTED DRAWING: Figure 4A

Description

Technical Field

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

Background Art

[0002] There is known a switching power supply device that switches input AC power or DC power and outputs DC power of a desired voltage. Among such switching power supply devices, those in which the power on the input side and the power on the output side are insulated by a transformer are called isolated switching power supply devices (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Note that the disclosure of the above prior art documents is incorporated herein by reference. The following analysis was made by the present inventors.

[0005] In the isolated switching power supply device disclosed in Patent Document 1, a choke coil is used in the circuit on the input side of the transformer. When the choke coil switches from a state of storing power to a state of discharging power, the current discharged from the choke coil is limited by the leakage inductance of the transformer connected in series with the choke coil. As a result, a surge voltage is generated across the switching element, so a surge voltage suppression circuit is required to protect the switching element. Further, in this isolated switching power supply device, the waveform of the current flowing through the ON-state switching element is rectangular, and the power loss generated in the switching element is larger than when the waveform of the current is sinusoidal.

[0006] An object of the present disclosure is to contribute to reducing a surge voltage applied to a switching element and reducing switching losses generated in the switching element in a switching power supply device.

Means for Solving the Problems

[0007] According to an aspect of the present disclosure, a first coil having one end connected to a terminal of a first power source with a first voltage polarity, a first active element and a second active element having one end connected to the other end of the first coil, a third active element and a fourth active element having the other end connected to a terminal of the first power source with a second voltage polarity, a first half-bridge circuit including a first transformer, a second half-bridge circuit including a second transformer, and a control circuit for controlling the first half-bridge circuit and the second half-bridge circuit so as to supply power from the first power source to a load or to regenerate power from a second power source instead of the load to the first power source are provided. The first half-bridge circuit includes a fifth active element having one end connected to the other end of the first active element and the other end connected to one end of a primary winding of the first transformer and one end of a primary winding of the second transformer, a sixth active element having one end connected to the other end of the fifth active element and the other end connected to one end of the third active element, a ninth active element having one end connected to a terminal of the load with a first voltage polarity and the other end connected to one end of a secondary winding of the first transformer, a tenth active element having one end connected to one end of the secondary winding of the first transformer and the other end connected to the second half-bridge circuit, a first capacitor having one end connected to one end of the fifth active element and the other end connected to the other end of the primary winding of the first transformer, a second capacitor having one end connected to the other end of the primary winding of the first transformer and the other end connected to the other end of the sixth active element, a third capacitor having one end connected to one end of the ninth active element and the other end connected to the other end of the secondary winding of the first transformer, and a fourth capacitor having one end connected to the other end of the secondary winding of the first transformer and the other end connected to the other end of the tenth active element.The second half-bridge circuit includes a seventh active element having one end connected to the other end of the second active element and the other end connected to one end of the primary winding of the first transformer and one end of the primary winding of the second transformer, an eighth active element having one end connected to the other end of the seventh active element and the other end connected to one end of the fourth active element, an eleventh active element having one end connected to the source of the tenth active element and the other end connected to the other end of the secondary winding of the second transformer, a twelfth active element having one end connected to the other end of the eleventh active element and the other end connected to the terminal of the load with the second voltage polarity, a fifth capacitor having one end connected to one end of the seventh active element and the other end connected to the other end of the primary winding of the second transformer, a sixth capacitor having one end connected to the other end of the primary winding of the second transformer and the other end connected to the other end of the eighth active element, a seventh capacitor having one end connected to one end of the eleventh active element and the other end connected to the other end of the secondary winding of the second transformer, and an eighth capacitor having one end connected to the other end of the secondary winding of the second transformer and the other end connected to the other end of the twelfth active element.

Advantages of the Invention

[0008] According to the aspect of the present disclosure, in a switching power supply device, it can contribute to suppressing the surge voltage applied to the switching element to a low level and reducing the switching loss generated in the switching element.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the embodiments described below. In FIGS. 2 to 9 and their descriptions, the same or corresponding elements are appropriately given the same reference numerals and symbols. On the other hand, between FIG. 1 and its description, and FIGS. 2 to 9 and their descriptions, the reference numerals and symbols are not unified. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationships of the respective elements, the ratios of the respective elements, the details of each process, etc. may be different from those in the present disclosure when implemented. Also, there may be parts where the dimensional relationships and process details are different between the drawings.

[0011] FIG. 1 is a diagram illustrating an example of the configuration of an isolated switching power supply device 1. As shown in FIG. 1, in the isolated switching power supply device 1, a primary circuit is connected to an AC power supply 101. The primary circuit includes capacitors 102 and 133, a diode bridge 110, a choke coil 120, a diode 131, a discharge power transistor 132, a full-bridge circuit 140, a negative power supply line 162, and a control device 180. The full-bridge circuit 140 includes power transistors 141 to 144, and the control device 180 includes a first control circuit 181 and a second control circuit 182. The full-bridge circuit 140 and the negative power supply line 162 of the primary circuit of the isolated switching power supply device 1 are connected to the primary winding of a transformer 150.

[0012] A secondary circuit is connected to the secondary winding of the transformer 150. In the secondary circuit, the anodes of diodes 171 and 172 are connected to both ends of the secondary winding of the transformer 150, and the positive electrodes of a capacitor 170 and a battery 190 are connected between the midpoint of the secondary winding and the ground. The isolated switching power supply device 1 rectifies and smooths the AC power supply 101 into a DC voltage by these components, and charges the battery 190.

[0013] In the isolated switching power supply device 1, when the power accumulated as charge in the choke coil 120 is discharged, the current is suppressed by the leakage inductance Lleak on the primary side of the transformer 150, so a surge voltage is generated across both ends of the choke coil 120. To counter this surge voltage, in the isolated switching power supply device 1, a snubber circuit composed of a diode 131, a discharge power transistor 132, and a capacitor 133 is required. Further, a first control circuit 181 is required to control the discharge power transistor 132 of the snubber circuit.

[0014] When control is performed so that the power transistors 141, 143 or the power transistors 142, 144 are simultaneously turned on, power is accumulated in the choke coil 120. Therefore, no power is input to the primary winding of the transformer 150, and the power is not transmitted to the secondary winding. Thus, in the isolated switching power supply device 1, every time the full-bridge circuit 140 switches power, a period occurs during which power is not transmitted from the primary winding to the secondary winding of the transformer 150. For this reason, the peak value (current value) of the current of the power transmitted from the primary winding to the secondary winding of the transformer 150 increases, and the power loss in the transformer 150 increases.

[0015] Also, since the waveform of the current flowing through each of the power transistors 141, 142, 143, 144 of the full-bridge circuit 140 is a part of a rectangular wave, power loss occurs every time switching is performed by the full-bridge circuit 140. In order to suppress the power loss in the full-bridge circuit 140 and the transformer 150, it is desirable to approximate the waveform of the current input to the primary side of the transformer 150 to a sine wave. However, for this purpose, it is necessary to perform PWM (Pulse Width Modulation) control on the switching of the full-bridge circuit 140, and the control for switching the full-bridge circuit 140 by the control device 180 must be speeded up.

[0016] On the one hand, when the switching of the full-bridge circuit 140 is PWM-controlled, the frequency of the power obtained on the secondary side of the transformer 150 becomes as low as about 10 Hz. Therefore, the voltage fluctuation of the power supplied to a load such as the battery 190 becomes large. For this reason, in order to suppress the voltage fluctuation of the power output from the isolated switching power supply device 1, it may be necessary to add a DC-DC converter to the isolated switching power supply device 1 to stabilize the voltage.

[0017] By replacing the diodes and the diodes 171 and 172 included in the full-bridge circuit 140 with switching elements such as transistors and appropriately controlling them, the power stored in the battery 190 can be regenerated to the AC power supply 101. However, in this case, it is necessary to perform hard switching on the switching operation of the switching elements replaced with the diodes 171 and 172, resulting in a large power loss.

[0018] [Embodiment] Hereinafter, the isolated switching power supply device 2 according to the embodiment of the present disclosure will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram illustrating a configuration example of the isolated switching power supply device 2 according to the embodiment of the present disclosure. FIG. 3 is a timing chart illustrating the operation of the isolated switching power supply device 2 illustrated in FIG. 2. Note that one example of the embodiment according to the present disclosure will be described later with further reference to FIGS. 4A to 4D and FIG. 5. In FIG. 3 and the like, power is described as energy. The letters A to D shown at the top of FIG. 3 respectively indicate the control periods in the isolated switching power supply device 2.

[0019] As illustrated in FIG. 2, the isolated switching power supply device 2 is a DC-DC converter that inputs DC power and outputs DC power. However, by making appropriate changes, it will be obvious to those skilled in the art that the isolated switching power supply device 2 can be an AC-DC converter, as shown in one example below.

[0020] In the following description, the case where the switching element is an n-channel enhancement type power MOSFET is taken as a specific example. However, in the isolated switching power supply device 2, it will be obvious to those skilled in the art that a p-channel enhancement type power MOSFET can be used by reversing the polarity of the power supply. Also, by appropriately modifying the isolated switching power supply device 2, it will be obvious to those skilled in the art that any type of active element other than a MOSFET, such as a bipolar transistor and an IGBT, can be used as the switching element.

[0021] First, an example of the configuration of the isolated switching power supply device 2 will be described. As illustrated in FIG. 2, the isolated switching power supply device 2 includes a choke coil L1, switching elements Q5, Q8, Q9, Q12, current resonance half-bridge circuits 20, 22, a power factor correction / inverter control circuit (not shown), and a frequency control circuit (not shown). The current resonance half-bridge circuit 20 is composed of switching elements Q6, Q7, Q13, Q14, capacitors C1, C2, C5, C6, choke coils L2, L4, and a transformer T1. The current resonance half-bridge circuit 22 is composed of switching elements Q10, Q11, Q15, Q16, capacitors C3, C4, C7, C8, choke coils L3, L5, and a transformer T2.

[0022] The switching elements Q5 to Q12 included in the isolated switching power supply device 2 are turned on (a state where conduction occurs between the drain and the source) or off (a state where non-conduction occurs between the drain and the source) according to the control by the power factor correction / inverter control circuit 46, respectively.

[0023] The circuit on the side (primary side) of the DC power supply Ei (first power supply) of the isolated switching power supply device 2 is connected between the positive voltage terminal and the negative voltage terminal of the DC power supply Ei and the primary sides of the transformers T1 and T2. The primary side circuit includes choke coils L1 to L3, capacitors C1 to C4, switching elements Q5 to Q12, and the primary side windings of the transformers T1 and T2. In the description of the isolated switching power supply device 2 and the like, an element that magnetically stores electric power is described as a "choke coil", but generally it is also simply called a "coil".

[0024] One end of the choke coil L1 is connected to the positive voltage terminal of the DC power supply Ei. The other end of the choke coil L1 is connected to the drain (one end) of the switching element Q5 of the current resonant half-bridge circuit 20 and the drain of the switching element Q9 of the current resonant half-bridge circuit 22.

[0025] The source (the other end) of the switching element Q5 (first active element) and the drain of the switching element Q6 (fifth active element) connected to each other form the first node n1. The node n1 is connected to one end of the capacitor C1. The source of the switching element Q7 (sixth active element) and the drain of the switching element Q8 connected to each other form the second node n2. The other end of the capacitor C2 is connected to the node n2.

[0026] The source of the switching element Q6 and the drain of the switching element Q7 connected to each other form the third node n3. One end of the primary side winding of the transformer T1 is connected to the node n3 via the choke coil L2. The other end of the capacitor C1 and one end of the capacitor C2 connected to each other form the fourth node n4. The node n4 is connected to the other end of the primary side winding of the transformer T1.

[0027] The source of the switching element Q9 (second switching element) and the drain of the switching element Q10 (seventh active element) connected to each other form the fifth node n5. The node n5 is connected to one end of the capacitor C3. The source of the switching element Q11 (eighth active element) and the drain of the switching element Q12 (fourth active element) connected to each other form the sixth node n6. The node n6 is connected to the other end of the capacitor C4.

[0028] The source of the switching element Q10 and the drain of the switching element Q11 connected to each other form the seventh node n7. The node n7 is connected to one end of the primary winding of the transformer T2 via the choke coil L3. The other end of the capacitor C3 and one end of the capacitor C4 connected to each other form the eighth node n8. The node n8 is connected to the other end of the primary winding of the transformer T2.

[0029] The circuit on the side (secondary side) of the load Lo or the battery BAT (second power source) of the isolated switching power supply device 2 is connected between the secondary sides of the transformers T1 and T2 and the load Lo or the battery BAT. The secondary side circuit includes the secondary windings of the transformers T1 and T2, the choke coils L4 and L5, the capacitors C5 to C8, and the switching elements Q13 to Q16. Note that a capacitor C9 may be connected between the positive voltage terminal (+; first voltage polarity) and the negative voltage terminal (−; second voltage polarity) of the load Lo or the battery BAT.

[0030] The drain of the capacitor C13 and one end of the capacitor C5 are connected to one end of the capacitor C9 and the positive voltage terminal of the load Lo or the battery BAT. The source of the switching element Q13 and the drain of the switching element Q14 connected to each other form the ninth node n9. The node n9 is connected to one end of the secondary winding of the transformer T1 via the choke coil L4.

[0031] The other end of the capacitor C5 and one end of the capacitor C6, which are connected to each other, form the tenth node n10. The node n10 is connected to the other end of the secondary winding of the transformer T1. The source of the switching element Q14 and the other end of the capacitor C6, which are connected to each other, form the eleventh node n11. The node n11 is connected to the current resonance half-bridge circuit 22.

[0032] The drain of the switching element Q15 and one end of the capacitor C7 are connected to the node n11. The source of the switching element Q15 and the drain of the switching element Q16, which are connected to each other, form the twelfth node n12. The node n12 is connected to one end of the secondary winding of the transformer T2 via the choke coil L5. The other end of the capacitor C7 and the drain of the capacitor C8, which are connected to each other, form the thirteenth node n13. The node n13 is connected to the other end of the secondary winding of the transformer T2. The source of the switching element Q16 and the other end of the capacitor C8 are connected to the other end of the capacitor C9 and the negative voltage terminal of the load Lo or the battery BAT.

[0033] Hereinafter, with reference to FIGS. 2 and 3, the operation of the isolated switching power supply device 2 when supplying power from the DC power supply Ei to the load Lo such as an electrical device will be described. In this description, the polarities of both terminals of the load Lo are not considered a problem.

[0034] As shown in FIG. 3, the switching elements Q5 and Q12 are controlled by a power factor improvement / inverter control circuit (not shown in FIG. 2) to be simultaneously turned on or off. The switching elements Q6 and Q13 are controlled by the power factor improvement / inverter control circuit to be simultaneously turned on or off. The switching elements Q7 and Q14 are controlled by the power factor improvement / inverter control circuit to be simultaneously turned on or off. The switching elements Q8 and Q9 are controlled by the power factor improvement / inverter control circuit to be simultaneously turned on or off. The switching elements Q10 and Q15 are controlled by the power factor improvement / inverter control circuit to be simultaneously turned on or off. The switching elements Q11 and Q16 are controlled by the power factor improvement / inverter control circuit to be simultaneously turned on or off. On the other hand, the switching elements Q6, Q13 and the switching elements Q7, Q14 are controlled by the power factor improvement / inverter control circuit to be alternately turned on or off.

[0035] First, the operation of the isolated switching power supply device 2 when supplying power from the DC power supply Ei to the load Lo will be described. When supplying power from the DC power supply Ei to the load Lo, if the operation of the isolated switching power supply device 2 is in the period A shown in FIG. 3, the power factor improvement / inverter control circuit controls the switching elements Q1 to Q4 to perform rectification, and further controls the states of the switching elements Q5 to Q16. As a result, the switching elements Q5, Q6, Q11, Q12, Q13, and Q16 of the isolated switching power supply device 2 are turned on, and the switching elements Q7, Q8, Q9, Q10, Q14, and Q15 are turned off (see also FIG. 4A).

[0036] During the period A, the current flows from the positive voltage terminal of the DC power supply Ei through the choke coil L1, the switching elements Q5, Q6, the switching elements Q11, Q12 to the negative voltage terminal of the DC power supply Ei. As a result, a voltage equivalent to the positive voltage terminal of the DC power supply Ei is applied to one end of the choke coil L1, and a current with a current value Iin flows, and the choke coil L1 accumulates power.

[0037] Also, a current flows between both ends of the capacitor C1 through the switching element Q6, the choke coil L2, and the primary winding of the transformer T1. As a result, the power stored in the capacitor C1 is transmitted from the primary winding of the transformer T1 to the secondary winding. The transmitted power is stored as charge in the capacitors C5 and C9 through the choke coil L4 and the switching element Q13, and supplied to the load Lo. On the other hand, a current flows between both ends of the capacitor C4 through the primary winding of the transformer T2, the choke coil L3, and the switching elements Q11 and Q12. As a result, the power stored in the capacitor C4 is transmitted to the secondary winding of the transformer T2. The transmitted power is further stored in the capacitors C8 and C9 through the choke coil L5 and the switching element Q16, and supplied to the load Lo.

[0038] When the operation of the isolated switching power supply device 2 transitions from the period A to the period B shown in FIG. 3 when supplying power from the DC power supply Ei to the load Lo, as shown in FIG. 3, the power factor improvement / inverter control circuit controls the states of Q5 to Q16. As a result, the switching elements Q5, Q6, Q8, Q9, Q10, Q12, Q13, and Q15 are turned on, and the switching elements Q7, Q11, Q14, and Q16 are turned off. That is, the switching elements Q8, Q9, Q10, and Q15 are changed from the off state to the on state, and the switching elements Q11 and Q16 are changed from the on state to the off state.

[0039] The other end of the choke coil L1 and the negative voltage terminal of the DC power supply Ei are connected via the switching element Q5, capacitors C1, C2 and the switching element Q8, and current flows through them. As a result, the power stored in the choke coil L1 is stored in the capacitor C1. Similarly, the other end of the choke coil L1 and the negative voltage terminal of the DC power supply Ei are connected via the switching element Q9, capacitors C3, C4 and the switching element Q12, and current flows through them. As a result, the power stored in the choke coil L1 is stored in the capacitor C3. As described above, the power stored in the choke coil L1 during period A is released during period B and stored in the capacitors C1 and C3.

[0040] Current flows between both ends of the capacitor C1 via the switching element Q6, the choke coil L2 and the primary winding of the transformer T1. As a result, the power stored in the capacitor C1 is transmitted to the secondary winding of the transformer T1. Further, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitor C5 via the choke coil L4 and the switching element Q13. Power has already been stored in the capacitors C6, C7, C8, and due to the stored power, the voltage difference across both ends of the capacitor C5 becomes the same as the voltage difference across both ends of the capacitors C6, C7, C8. Therefore, when power is stored in the capacitor C5, this power is supplied from the capacitors C5, C6, C7, C8 to the capacitor C9 and the load Lo.

[0041] Also, a current flows between both ends of the capacitor C3 through the switching element Q10, the choke coil L3, and the primary winding of the transformer T2. As a result, the power stored in the capacitor C3 is transmitted to the secondary winding of the transformer T1. Further, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitor C7 through the choke coil L5 and the switching element Q15. Power has already been stored in the capacitors C5, C6, and C8, and due to the stored power, the voltage difference across both ends of the capacitor C7 becomes the same as the voltage difference across both ends of the capacitors C5, C6, and C8. Therefore, when power is stored in the capacitor C7, this power is supplied from the capacitors C5, C6, C7, and C8 to the capacitor C9 and the load Lo.

[0042] When supplying power from the DC power supply Ei to the load Lo, when the operation of the isolated switching power supply device 2 transitions from the period B to the period C shown in FIG. 3, the power factor improvement / inverter control circuit controls the states of Q5 to Q16. As a result, the switching elements Q7, Q8, Q9, Q10, Q14, Q15, and Q16 are turned on, and the switching elements Q5, Q6, Q10, Q11, Q12, and Q13 are turned off. That is, the switching elements Q7 and Q14 are changed from the off state to the on state, and the switching elements Q6, Q13, Q5, and Q12 are changed from the on state to the off state (see also FIG. 4C). The choke coil L1 is connected in series with the negative voltage terminal of the DC power supply Ei through the switching elements Q6, Q6, Q11, and Q12, a current with a current value Iin flows through the choke coil L1, and power is stored in the choke coil L1.

[0043] A current flows between one end and the other end of capacitor C2 via the primary winding of transformer T1, choke coil L2, and switching element Q7. As a result, the power stored in capacitor C2 is transmitted to the secondary winding of transformer T1. The transmitted power is stored in capacitor C6 via capacitor C6, switching element Q14, and choke coil L4. Power has already been stored in capacitors C5, C7, and C8, and the voltage difference across both ends of capacitor C6 becomes the same as the voltage difference across both ends of capacitors C5, C7, and C8 due to the stored power. Therefore, when power is stored in capacitor C6, this power is supplied from capacitors C5, C6, C7, and C8 to capacitor C9 and load Lo.

[0044] A current flows between one end and the other end of capacitor C3 via switching element Q10, choke coil L3, and the primary winding of transformer T2. As a result, the power stored in capacitor C3 is transmitted to the secondary winding of transformer T2. Thereby, the transmitted power is sent to capacitor C7 from the secondary winding of transformer T2 via choke coil L5 and switching element Q15. Power has already been stored in capacitors C5, C6, and C8, and the voltage difference across both ends of capacitor C7 becomes the same as the voltage difference across both ends of capacitors C5, C6, and C8 due to the stored power. Therefore, when power is stored in capacitor C7, this power is supplied from capacitors C5, C6, C7, and C8 to capacitor C9 and load Lo.

[0045] When supplying power from DC power supply Ei to load Lo, when the operation of isolated switching power supply device 2 transitions from period C to period D shown in FIG. 3, the power factor improvement / inverter control circuit controls the states of Q5 to Q16. As a result, switching elements Q5, Q7, Q8, Q9, Q11, Q14, and Q16 are turned on, and Q6, Q10, Q13, and Q15 are turned off. That is, switching elements Q5, Q11, Q12, and Q16 are changed from the off state to the on state, and switching elements Q10 and Q15 are changed from the on state to the off state (see also FIG. 4D).

[0046] The choke coil L1 is DC-isolated from the negative voltage terminal of the DC power supply Ei. On the other hand, the other end of the choke coil L1 and the negative voltage terminal of the DC power supply Ei are connected via the switching element Q5, the capacitors C1, C2, and the switching element Q8, and current flows through them. As a result, the power stored in the choke coil L1 is stored in the capacitor C2.

[0047] Similarly, the other end of the choke coil L1 and the negative voltage terminal of the DC power supply Ei are connected via the switching element Q9, the capacitors C3, C4, and the switching element Q12, and current flows through them. As a result, the power stored in the choke coil L1 is stored in the capacitor C3. As described above, the power stored in the choke coil L1 during period A is released during period B and stored in the capacitors C1 and C3.

[0048] Current flows between one end and the other end of the capacitor C1 via the switching element Q6, the choke coil L2, and the primary winding of the transformer T1. As a result, the power stored in the capacitor C3 is transmitted to the secondary winding of the transformer T1. Furthermore, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitors C5 and C9 via the choke coil L4 and the switching element Q13 and supplied to the load Lo.

[0049] Also, current flows between one end and the other end of the capacitor C3 via the switching element Q10, the choke coil L3, and the primary winding of the transformer T2. As a result, the power stored in the capacitor C3 is transmitted to the secondary winding of the transformer T1. Furthermore, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitors C7 and C9 via the choke coil L5 and the switching element Q15 and supplied to the load Lo.

[0050] The isolated switching power supply device 2 supplies power from the DC power supply Ei to the load Lo by repeating the operations in the periods A to D described above.

[0051] According to the operation of the isolated switching power supply device 2 shown in FIG. 3, current flows from the choke coil L1 to the capacitors C1, C2, C3, and C4 without restriction and is accumulated as charge. Therefore, the generation of surge voltage at both ends of the choke coil L1 is suppressed, and a surge voltage suppression circuit is not required.

[0052] In the current resonance half-bridge circuit 20 described above, the switching elements Q6 and Q7 can be controlled to be alternately in the ON state and the OFF state with a duty ratio of 50%. With such control, the switching elements Q6 and Q7 are not both in the ON state at the same time. Also, in the current resonance half-bridge circuit 22 described above, the switching elements Q10 and Q11 are also controlled to be alternately in the ON state and the OFF state with a duty ratio of 50%, and both of them are not in the ON state at the same time.

[0053] With such control, the switching elements Q10 and Q11 are not both in the ON state or the OFF state at the same time. By controlling the switching elements Q6, Q7, Q10, and Q11 described above, the power supply from the DC power supply Ei to the load Lo is optimized, the efficiency of the isolated switching power supply device 2 is improved, and the voltage value Vo generated in the load Lo is stabilized.

[0054] Furthermore, in the isolated switching power supply device 2, the capacitors C1, C2, C5, and C6, the choke coil L2, the transformer T1, and the choke coil L4 form a resonance circuit. Also, the capacitors C3, C4, C7, and C8, the choke coil L3, the transformer T2, and the choke coil L5, and the capacitors C7 and C8 form a resonance circuit. By matching the resonance frequencies of these resonance circuits and setting the switching frequency in the isolated switching power supply device 2 to match this resonance frequency, the waveform of the current flowing through these resonance circuits becomes sinusoidal.

[0055] Therefore, when the switching elements Q6, Q7, Q10, and Q11 are switched at the resonance frequency of the resonance circuits formed in the current resonance half-bridge circuits 20 and 22, the waveforms of the currents flowing through these switching elements also become sinusoidal, and the losses caused by the switching in these elements are reduced. On the other hand, when the switching elements Q6, Q7, Q10, and Q11 are switched at a frequency far from these resonance circuits, the waveforms of the currents flowing through these switching elements become rectangular, and the losses caused by the switching in these elements increase. As described above, by setting the switching frequency for turning each of the switching elements ON or OFF to the resonance frequency of the resonance circuits formed in the current resonance half-bridge circuits 20 and 22, the efficiency of the isolated switching power supply device 2 is further improved, and the voltage value Vo generated in the load Lo also becomes more stable.

[0056] Next, with reference to FIGS. 2 and 3, the operation of the isolated switching power supply device 2 when regenerating power from the battery BAT capable of supplying power to the DC power supply Ei side will be described. As shown in FIG. 2, in this description, for example, a rechargeable battery BAT is connected to the secondary-side circuit of the isolated switching power supply device 2 instead of the load Lo.

[0057] One end of the battery BAT is a positive voltage terminal (+) and is connected to the drain of the switching element Q13 of the current resonance half-bridge circuit 20 and one end of the capacitor C5. The other end of the battery BAT is a negative voltage terminal (−) and is connected to the source of the switching element Q16 and the other end of the capacitor C8. For example, the battery BAT is charged by being supplied with power by the isolated switching power supply device 2 from the DC power supply Ei. As shown in FIG. 3, the choke coil L1 stores power before the period A starts.

[0058] When regenerating by supplying power from the battery BAT to the DC power supply Ei, if the operation of the isolated switching power supply device 2 is in the period A shown in FIG. 3, the power factor improvement / inverter control circuit controls the states of the switching elements Q5 to Q16. As a result, the switching elements Q5, Q6, Q11, Q12, Q13, Q16 of the isolated switching power supply device 2 are turned on, and the switching elements Q7, Q8, Q9, Q10, Q14, Q15 are turned off (see also FIG. 4A).

[0059] Current flows from the positive voltage terminal of the battery BAT to the negative voltage terminal through the switching element Q13, the choke coil L4, the secondary winding of the transformer T1, the capacitors C6, C7, the secondary winding of the transformer T2, the choke coil L5, and the switching element Q16. As a result, power of a voltage corresponding to the ratio of the number of primary windings to the number of secondary windings of the transformer T1 is transmitted from the secondary winding of the transformer T1 to the primary winding. Similarly, power of a voltage corresponding to the ratio of the number of primary windings to the number of secondary windings of the transformer T2 is transmitted from the secondary winding of the transformer T2 to the primary winding.

[0060] The power transmitted to the primary winding of the transformer T1 is stored in the capacitor C1 through the choke coil L2 and the switching element Q6. Also, the power transmitted to the primary winding of the transformer T2 is stored in the capacitor C4 through the choke coil L3 and the switching element Q11.

[0061] As described above, the choke coil L1 stores power before the period A, and current flows between one end and the other end of the choke coil L1 through the positive voltage terminal of the DC power supply Ei, the negative voltage terminal of the DC power supply Ei, and the switching elements Q5, Q6, Q11, Q12. Due to the operation of the isolated switching power supply device 2 described above, the power stored in the choke coil L1 is released and supplied to the DC power supply Ei for regeneration.

[0062] When regenerating by supplying power from the battery BAT to the DC power supply Ei, when the operation of the isolated switching power supply device 2 shifts from the period A shown in FIG. 3 to the period B, the power factor improvement / inverter control circuit controls the states of the switching elements Q5 to Q16. As a result, the switching elements Q5, Q6, Q8, Q9, Q10, Q12, Q13, Q15 are turned on, and the switching elements Q7, Q11, Q14, Q16 are turned off. That is, the switching elements Q8, Q9, Q10, Q15 are changed from the off state to the on state, and the switching elements Q11, Q16 are changed from the on state to the off state (see also FIG. 4B).

[0063] Current flows from the positive voltage terminal of the battery BAT through the switching element Q13, the choke coil L4, the secondary winding of the transformer T1, the capacitor C6, the switching element Q15, the choke coil L15, the secondary winding of the transformer T2, and the capacitor C8 to the negative voltage terminal of the battery BAT. Electric power of a voltage corresponding to the ratio of the number of turns of the primary winding and the number of turns of the secondary winding of the transformer T1 is transmitted to the primary side of the transformer T1.

[0064] The transmitted electric power is stored in the capacitor C1 via the choke coil L2 and the switching element Q6. Electric power of a voltage corresponding to the ratio of the number of turns of the primary winding and the number of turns of the secondary winding of the transformer T2 is transmitted to the primary side of the transformer T2. The transmitted electric power is stored in the capacitor C3 via the choke coil L3 and the switching element Q10.

[0065] A current flows between one end and the other end of capacitor C1 through switching element Q5, choke coil L1, the positive voltage terminal of DC power supply Ei, the negative voltage terminal of DC power supply Ei, switching element Q8, and capacitor C2. Also, a current flows between one end and the other end of capacitor C3 through switching element Q9, choke coil L1, the positive voltage terminal of DC power supply Ei, the negative voltage terminal of DC power supply Ei, switching element Q12, and capacitor C4. As a result, a current flows through choke coil L1, power is stored in choke coil L1, and the power stored in capacitors C1 and C3 is supplied to and regenerated by DC power supply Ei.

[0066] When supplying power to and regenerating DC power supply Ei from battery BAT, when the operation of isolated switching power supply device 2 shifts from period B to period C shown in FIG. 3, the power factor improvement / inverter control circuit controls the states of switching elements Q5 to Q16. As a result, switching elements Q7, Q8, Q9, Q10, Q14, Q15 become ON states, and switching elements Q5, Q6, Q10, Q11, Q12, Q13 become OFF states. That is, switching elements Q7, Q14 are changed from OFF states to ON states, and switching elements Q6, Q13, Q5, Q12 are changed from ON states to OFF states (see also FIG. 4C).

[0067] A current flows from the positive voltage terminal of battery BAT through capacitor C3, the secondary winding of transformer T1, choke coil L4, switching elements Q14, Q15, choke coil L5, the secondary winding of transformer T2, and switching element Q8 to the negative voltage terminal of battery BAT. As a result, power of a voltage corresponding to the ratio of the number of turns of the primary winding to the number of turns of the secondary winding of transformers T1 and T2 is transmitted from the secondary winding of transformer T1 and the secondary winding of transformer T2 to the primary winding of transformer T1 and the primary winding of transformer T2.

[0068] In the primary winding of transformer T1, current flows through capacitor C2, switching element Q7, and choke coil L2, and the power transmitted to the primary winding of transformer T1 is stored in capacitor C2. Also, in the primary winding of transformer T2, current flows through choke coil L3, switching element Q10, and capacitor C3, and the power transmitted to the primary winding of transformer T2 is stored in capacitor C3.

[0069] Current flows between one end and the other end of choke coil L1 through the positive voltage terminal of DC power supply Ei, the negative voltage terminal of DC power supply Ei, and switching elements Q4, Q7, Q8, Q9, Q10. As a result, the power stored in choke coil L1 is released and supplied to DC power supply Ei for regeneration.

[0070] When power is supplied from battery BAT to DC power supply Ei for regeneration, when the operation of the isolated switching power supply device 2 transitions from period C to period D shown in FIG. 3, the power factor improvement / inverter control circuit controls the states of switching elements Q5 to Q16. As a result, switching elements Q5, Q7, Q8, Q9, Q11, Q14, Q16 are turned on, and Q6, Q10, Q13, Q15 are turned off. That is, switching elements Q5, Q11, Q12, Q16 are turned on from the off state, and switching elements Q10, Q15 are turned off from the on state (see also FIG. 4D).

[0071] Current flows from the positive voltage terminal of battery BAT to the negative voltage terminal of battery BAT through capacitor C5, the secondary winding of transformer T1, choke coil L4, switching element Q14, capacitor C7, the secondary winding of transformer T2, choke coil L5, and switching element Q16. As a result, power of a voltage corresponding to the ratio of the number of turns of the primary winding to the number of turns of the secondary winding of transformers T1 and T2 is transmitted from the secondary winding of transformer T1 and the secondary winding of transformer T2 to the primary winding of transformer T1 and the primary winding of transformer T2.

[0072] Furthermore, current flows from the other end of the primary winding of transformer T1, through capacitor C2, switching element Q7, and choke coil L2, to one end of the primary winding of transformer T1, and power is stored in capacitor C2. Also, current flows from the other end of the primary winding of transformer T2, through capacitor C4, switching element Q11, and choke coil L3, to one end of the primary winding of transformer T1, and power is stored in capacitor C4.

[0073] As described above, power is stored in capacitors C1, C2, C3, and C4. Due to the power stored in capacitors C1, C2, C3, and C4, current flows between switching elements Q5, Q8, Q9, Q12, choke coil L1, the positive voltage terminal of DC power supply Ei, the negative voltage terminal of DC power supply Ei, and switching elements Q8, Q12. As a result, power is supplied from battery BAT to DC power supply Ei and regenerated, and power is stored in choke coil L1.

[0074] By repeating the operations in periods A to D described above, the isolated switching power supply device 2 supplies the power of the voltage value Vo stored in battery BAT to DC power supply Ei and regenerates it.

[0075] In the operation of the isolated switching power supply device 2 shown in FIG. 3, the switching elements Q5 and Q6 of the current resonant half-bridge circuit 20 are respectively turned ON or OFF alternately with a duty ratio of 50% by control, and both of them are not turned ON simultaneously. Similarly, the switching elements Q10 and Q11 of the current resonant half-bridge circuit 22 are turned ON or OFF alternately with a duty ratio of 50%, and both of them are not turned ON simultaneously. Therefore, in the isolated switching power supply device 2, power losses that occur when both of the switching elements Q5 and Q6 are turned ON, and power losses that occur when both of the switching elements Q10 and Q11 are turned ON do not occur. Therefore, the losses generated in the isolated switching power supply device 2 are reduced.

[0076] [Embodiment] Hereinafter, with further reference to FIGS. 4A to 4D and FIG. 5, an embodiment of the isolated switching power supply device 3 according to the present disclosure will be described. FIG. 4A is a diagram illustrating an embodiment of the isolated switching power supply device 3 according to the present disclosure, and is a diagram illustrating the ON / OFF states of the respective switching elements in period A shown in FIG. 3. FIG. 4B is a diagram showing an embodiment of the isolated switching power supply device 3 according to the present disclosure, and is a diagram illustrating the ON / OFF states of the respective switching elements in period B shown in FIG. 3. FIG. 4C is a diagram showing an embodiment of the isolated switching power supply device 3 according to the present disclosure, and is a diagram illustrating the ON / OFF states of the respective switching elements in period C shown in FIG. 3. FIG. 4D is a diagram showing an embodiment of the isolated switching power supply device 3 according to the present disclosure, and is a diagram illustrating the ON / OFF states of the respective switching elements in period D shown in FIG. 3. FIG. 5 is a timing chart illustrating the operation of the isolated switching power supply device 3 illustrated in FIGS. 4A to 4D. As shown in FIGS. 4A to 4D, the current resonance half-bridge circuits 20 and 22 of the isolated switching power supply device 3 are connected to the full-wave rectifier circuit 40 instead of the DC power supply Ei. Further, the isolated switching power supply device 3 includes a power factor improvement / inverter control circuit 46, a frequency control circuit 44, and a current detection circuit.

[0077] The full-wave rectifier circuit 40 is connected to the AC power supply Vi and includes switching elements Q1, Q2, Q3, and Q4 that form a bridge for full-wave rectifying the AC power supplied from the AC power supply Vi. In the full-wave rectifier circuit 40, the source of the switching element Q1 and the drain of the switching element Q2 are connected to one end of the AC power supply Vi, and the source of the switching element Q3 and the drain of the switching element Q4 are connected to the other end of the AC power supply Vi. The drains of the switching elements Q1 and Q3 are connected to one end of the choke coil L1. The sources of the switching elements Q2 and Q4 are connected to the sources of the switching element Q8 of the current resonance half-bridge circuit 20 and the switching element Q12 of the current resonance half-bridge circuit 22.

[0078] The frequency control circuit 44 adjusts the frequency of the reference frequency signal fsw so that the voltage value Vo at the positive voltage terminal of the load Lo or the battery BAT becomes a specified value, and outputs it to the power factor improvement / inverter control circuit 46.

[0079] The power factor improvement / inverter control circuit 46 outputs a control signal (not shown) to the gates of the switching elements Q1, Q2, Q3, Q4 respectively, and sets each of the switching elements Q1, Q2, Q3, Q4 to the ON state or the OFF state as shown in FIG. 5. The voltage value across both ends of the AC power supply Vi is input to the power factor improvement / inverter control circuit 46 (not shown). When one end of the AC power supply Vi is at a positive voltage and the other end is at a negative voltage, the power factor improvement / inverter control circuit 46 turns on the switching elements Q1, Q4 and turns off the switching elements Q2, Q3. Also, when one end of the AC power supply Vi is at a negative voltage and the other end is at a positive voltage, the power factor improvement / inverter control circuit 46 turns on the switching elements Q2, Q3 and turns off the switching elements Q1, Q4. By performing such control on the full-wave rectifier circuit 40, the power factor improvement / inverter control circuit 46 causes the full-wave rectifier circuit 40 to perform full-wave rectification of the AC power supplied from the AC power supply Vi. As a result of such control of the power factor improvement / inverter control circuit 46, the voltage waveform of the power output from the full-wave rectifier circuit 40 becomes a full-wave rectified waveform in which the negative voltage portion of the sinusoidal power supply voltage is folded back to a positive voltage.

[0080] In addition to the reference frequency signal fsw and the voltage value across both ends of the AC power supply Vi described above, the voltage value of the power rectified by the full-wave rectifier circuit 40 and the current value flowing between the sources of the switching elements Q2, Q4 and the switching elements Q8, Q12 detected by the current detection circuit are input to the power factor improvement / inverter control circuit 46.

[0081] In addition, the power factor improvement / inverter control circuit 46 receives the current value flowing between the sources of the switching elements Q2 and Q4 and the sources of the switching elements Q8 and Q12. The value of the current flowing between the sources of the switching elements Q2 and Q4 and the switching elements Q8 and Q12 is equal to the current value Iin flowing through the choke coil L1. Further, the power factor improvement / inverter control circuit 46 receives the added value (Vc1 + Vc2) of the voltage value Vc1 of the capacitor C1 and the voltage value Vc2 of the capacitor C2, and the added value (Vc3 + Vc4) of the voltage value Vc3 of the capacitor C3 and the voltage value Vc4 of the capacitor C4.

[0082] Based on these inputs, the power factor improvement / inverter control circuit 46 outputs control signals Q5G to Q16G to the gates of the switching elements Q5 to Q16 included in the current resonance half-bridge circuits 20 and 22, respectively. The power factor improvement / inverter control circuit 46 turns on or off the switching elements Q5 to Q16 by the control signals Q5G to Q16G, performs switching with the frequency of the reference frequency signal fsw as the switching frequency of PWM control, and converts the power supplied from the AC power supply Vi into the power with the voltage value Vo and supplies it to the load Lo or the battery BAT.

[0083] Specifically, the power factor improvement / inverter control circuit 46 controls the switching elements Q5 to Q16 included in the current resonance half-bridge circuits 20 and 22 so that the waveform of the current flowing through the choke coil L1 becomes the same as the waveform of the voltage of the full-wave rectified power of the full-wave rectifier circuit 40, and improves the power factor of the power supplied to the load Lo or the battery BAT. In addition, the power factor improvement / inverter control circuit 46 stabilizes the input added values (Vc1 + Vc2) and (Vc3 + Vc4) to predetermined values (predetermined values). The control loop for power factor improvement is about several kHz, while the frequency of the control loop for the added values (Vc1 + Vc2) and (Vc3 + Vc4) is as low as about 10 Hz. Thus, when the added values (Vc1 + Vc2) and (Vc3 + Vc4) are stabilized, the operation of the entire current resonance half-bridge circuits 20 and 22 becomes stable.

[0084] The operation of the isolated switching power supply device 3 will be described below. The operation of the isolated switching power supply device 3 described with reference to FIG. 3 is the same as the operation of the isolated switching power supply device 2 (FIG. 2) when the DC power supply Ei is replaced with a full-wave rectifier circuit 40.

[0085] As shown in FIG. 5, the power factor correction / inverter control circuit 46 alternately turns on or off the switching elements Q6 and Q7 in synchronization with the reference frequency signal fsw so that the duty ratio of the on state is 50%. Similarly, the power factor correction / inverter control circuit 46 alternately turns on or off the switching elements Q10 and Q11 so that the duty ratio of the on state is 50%.

[0086] In particular, the power factor correction / inverter control circuit 46 controls these switching elements Q6, Q7, Q10, and Q11 so that the switching elements Q6 and Q7 do not simultaneously turn on, and the switching elements Q10 and Q11 do not simultaneously turn on. Note that the power factor correction / inverter control circuit 46 may provide a dead time in which both of the switching elements Q6 and Q7 are in the off state in the control of the switching elements Q6, Q7, Q10, and Q11, and may also provide a dead time in which both of the switching elements Q10 and Q11 are in the off state.

[0087] The power factor correction / inverter control circuit 46 performs PWM control on the switching elements Q6, Q7 and the switching elements Q10, Q11, and controls the phase difference between the switching by the switching elements Q6, Q7 and the switching by the switching elements Q10, Q11. When the power factor correction / inverter control circuit 46 turns on the switching elements Q6 and Q11 and turns off Q5 and Q10, power is accumulated in the choke coil L1. On the other hand, when the power factor correction / inverter control circuit 46 turns on the switching elements Q5 and Q10 and turns off Q6 and Q11, the power accumulated in the choke coil L1 is supplied to the current resonance half-bridge circuits 20 and 22.

[0088] The power factor improvement / inverter control circuit 46 controls the ratio of the time during which power is accumulated in the choke coil L1 to the time during which power is supplied from the choke coil L1 to the current resonance half - bridge circuits 20 and 22, so that the current value Iin of the current flowing through the choke coil L1 and the voltage value Vo of the load Lo or the battery BAT are set to specified values. That is, the power factor improvement / inverter control circuit 46 controls the ratio of the time when the switching elements Q6 and Q11 are in the ON state and the switching elements Q5 and Q10 are in the OFF state to the time when the switching elements Q6 and Q11 are in the ON state and the switching elements Q5 and Q10 are in the OFF state, thereby adjusting the current value Iin and the voltage value Vo to the specified values.

[0089] First, the operation of the isolated switching power supply device 3 when power is supplied from the full - wave rectifier circuit 40 to the load Lo will be described. When power is supplied from the full - wave rectifier circuit 40 to the load Lo and the operation of the isolated switching power supply device 3 is in the period A shown in FIG. 3, the power factor improvement / inverter control circuit 46 controls the states of the switching elements Q5 to Q16 as shown in FIGS. 4A and 5. As a result, the switching elements Q5, Q6, Q11, Q12, Q13, and Q16 of the isolated switching power supply device 3 are turned on, and the switching elements Q7, Q8, Q9, Q10, Q14, and Q15 are turned off.

[0090] During the period A, the current flows from the positive voltage terminal of the full - wave rectifier circuit 40, through the choke coil L1, the switching elements Q5 and Q6, and the switching elements Q11 and Q12, to the negative voltage terminal of the full - wave rectifier circuit 40. As a result, a voltage equivalent to the positive voltage terminal of the full - wave rectifier circuit 40 is applied to one end of the choke coil L1, and a current with a current value Iin flows, and the choke coil L1 accumulates power.

[0091] Also, a current flows between one end and the other end of the capacitor C1 through the switching element Q6, the choke coil L2, and the primary winding of the transformer T1. As a result, the power stored in the capacitor C1 is transmitted from the primary winding of the transformer T1 to the secondary winding. The transmitted power is stored as charge in the capacitors C5 and C9 through the choke coil L4 and the switching element Q13, and supplied to the load Lo. On the other hand, a current flows between one end and the other end of the capacitor C4 through the primary winding of the transformer T2, the choke coil L3, and the switching elements Q11 and Q12. As a result, the power stored in the capacitor C4 is transmitted to the secondary winding of the transformer T2. The transmitted power is further stored in the capacitors C8 and C9 through the choke coil L5 and the switching element Q16, and supplied to the load Lo.

[0092] When supplying power from the full-wave rectifier circuit 40 to the load Lo, when the operation of the isolated switching power supply device 3 shifts from the period A to the period B shown in FIG. 3, as shown in FIGS. 4B and 5, the power factor improvement / inverter control circuit 46 controls the states of Q5 to Q16. As a result, the switching elements Q5, Q6, Q8, Q9, Q10, Q12, Q13, Q15 are turned on, and the switching elements Q7, Q11, Q14, Q16 are turned off. That is, the switching elements Q8, Q9, Q10, Q15 are turned on from the off state, and the switching elements Q11, Q16 are turned off from the on state.

[0093] A current flows between both ends of the capacitor C1 through the switching element Q6, the choke coil L2, and the primary winding of the transformer T1. As a result, the power stored in the capacitor C1 is transmitted to the secondary winding of the transformer T1. Further, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitor C5 through the choke coil L4 and the switching element Q13. Power has already been stored in the capacitors C6, C7, and C8, and due to the stored power, the voltage difference across both ends of the capacitor C5 becomes the same as the voltage difference across both ends of the capacitors C6, C7, and C8. Therefore, when power is stored in the capacitor C5, this power is supplied from the capacitors C5, C6, C7, and C8 to the capacitor C9 and the load Lo.

[0094] Also, a current flows between both ends of the capacitor C3 through the switching element Q10, the choke coil L3, and the primary winding of the transformer T2. As a result, the power stored in the capacitor C3 is transmitted to the secondary winding of the transformer T1. Further, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitor C7 through the choke coil L5 and the switching element Q15. Power has already been stored in the capacitors C5, C6, and C8, and due to the stored power, the voltage difference across both ends of the capacitor C7 becomes the same as the voltage difference across both ends of the capacitors C5, C6, and C8. Therefore, when power is stored in the capacitor C7, this power is supplied from the capacitors C5, C6, C7, and C8 to the capacitor C9 and the load Lo.

[0095] When supplying power from the DC power supply Ei to the load Lo, when the operation of the isolated switching power supply device 2 transitions from the period B shown in FIG. 3 to the period C, the power factor improvement / inverter control circuit controls the states of Q5 to Q16. As a result, the switching elements Q7, Q8, Q9, Q10, Q14, Q15, Q16 are turned on, and the switching elements Q5, Q6, Q10, Q11, Q12, Q13 are turned off. That is, the switching elements Q7, Q14 are changed from the off state to the on state, and the switching elements Q6, Q13, Q5, Q12 are changed from the on state to the off state (see also FIG. 4C). The choke coil L1 is connected in series with the negative voltage terminal of the DC power supply Ei via the switching elements Q6, Q6, Q11, Q12, and a current with a current value Iin flows through the choke coil L1, and power is stored in the choke coil L1.

[0096] A current flows between one end and the other end of the capacitor C2 via the primary winding of the transformer T1, the choke coil L2, and the switching element Q7. As a result, the power stored in the capacitor C2 is transmitted to the secondary winding of the transformer T1. The transmitted power is stored in the capacitor C6 via the capacitor C6, the switching element Q14, and the choke coil L4. Power has already been stored in the capacitors C5, C7, C8, and the voltage difference across the capacitor C6 becomes the same as the voltage difference across the capacitors C5, C7, C8 due to the stored power. Therefore, when power is stored in the capacitor C6, this power is supplied from the capacitors C5, C6, C7, C8 to the capacitor C9 and the load Lo.

[0097] A current flows between one end and the other end of the capacitor C3 through the switching element Q10, the choke coil L3, and the primary winding of the transformer T2. As a result, the power stored in the capacitor C3 is transmitted to the secondary winding of the transformer T2. Thus, the transmitted power is supplied to the capacitor C7 from the secondary winding of the transformer T2 through the choke coil L5 and the switching element Q15. Power has already been stored in the capacitors C5, C6, and C8, and due to the stored power, the voltage difference across both ends of the capacitor C7 becomes the same as the voltage difference across both ends of the capacitors C5, C6, and C8. Therefore, when power is stored in the capacitor C7, this power is supplied from the capacitors C5, C6, C7, and C8 to the capacitor C9 and the load Lo.

[0098] When supplying power from the full-wave rectifier circuit 40 to the load Lo, when the operation of the isolated switching power supply device 3 transitions from the period C to the period D shown in FIG. 3, as shown in FIGS. 4D and 5, the power factor improvement / inverter control circuit 46 controls the states of Q5 to Q16. As a result, the switching elements Q5, Q7, Q8, Q9, Q11, Q14, and Q16 are turned on, and Q6, Q10, Q13, and Q15 are turned off. That is, the switching elements Q5, Q11, Q12, and Q16 are changed from the off state to the on state, and the switching elements Q10 and Q15 are changed from the on state to the off state.

[0099] The choke coil L1 is DC-isolated from the negative voltage terminal of the full-wave rectifier circuit 40. On the other hand, the other end of the choke coil L1 and the negative voltage terminal of the full-wave rectifier circuit 40 are connected via the switching element Q5, the capacitors C1, C2, and the switching element Q8, and current flows through them. As a result, the power stored in the choke coil L1 is stored in the capacitor C2. Similarly, the other end of the choke coil L1 and the negative voltage terminal of the full-wave rectifier circuit 40 are connected via the switching element Q9, the capacitors C3, C4, and the switching element Q12, and current flows through them. As a result, the power stored in the choke coil L1 is stored in the capacitor C3. As described above, the power stored in the choke coil L1 during period A is released during period B and stored in the capacitors C2 and C3.

[0100] A current flows between one end and the other end of the capacitor C1 via the switching element Q6, the choke coil L2, and the primary winding of the transformer T1. As a result, the power stored in the capacitor C3 is transmitted to the secondary winding of the transformer T1. Further, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitors C5 and C9 via the choke coil L4 and the switching element Q13 and supplied to the load Lo.

[0101] Also, a current flows between one end and the other end of the capacitor C3 via the switching element Q10, the choke coil L3, and the primary winding of the transformer T2. As a result, the power stored in the capacitor C3 is transmitted to the secondary winding of the transformer T1. Further, the power transmitted to the secondary winding of the transformer T1 is stored in the capacitors C7 and C9 via the choke coil L5 and the switching element Q15 and supplied to the load Lo.

[0102] The isolated switching power supply device 3 supplies power from the AC power supply Vi to the load Lo by repeating the operations in the periods A to D described above.

[0103] Next, with reference to FIGS. 3, 4A to 4D, the operation of the isolated switching power supply device 3 when the load Lo is replaced by a power - supply - capable battery BAT and the battery BAT supplies power to the AC power supply Vi for regeneration will be described. As shown in FIGS. 4A and the like, in this description, for example, a charge - and - discharge - capable battery BAT is connected to the secondary - side circuit of the isolated switching power supply device 3 instead of the load Lo.

[0104] One end of the battery is a positive - voltage terminal (+) and is connected to the drain of the switching element Q13 of the current - resonant half - bridge circuit 20 and one end of the capacitor C5. Also, the other end of the battery is a negative - voltage terminal (−) and is connected to the source of the switching element Q16 and the other end of the capacitor C8. For example, the battery BAT is supplied with power from the DC power supply Ei by the isolated switching power supply device 3 and is charged. As shown in FIG. 3, the choke coil L1 stores power before the period A starts.

[0105] When the operation of the isolated switching power supply device 3 is in the period A shown in FIG. 3 when the battery BAT supplies power to the DC power supply Ei for regeneration, as shown in FIGS. 4A and 5, the power - factor - improvement / inverter control circuit 46 controls the switching elements Q1 to Q4 for the rectification operation and further controls the states of the switching elements Q5 to Q16. As a result, the switching elements Q5, Q6, Q11, Q12, Q13, Q16 of the isolated switching power supply device 3 are turned on, and the switching elements Q7, Q8, Q9, Q10, Q14, Q15 are turned off.

[0106] Current flows from the positive voltage terminal to the negative voltage terminal of the battery BAT through the switching element Q13, the choke coil L4, the secondary winding of the transformer T1, the capacitors C6, C7, the secondary winding of the transformer T2, the choke coil L5, and the switching element Q16. As a result, power of a voltage corresponding to the ratio of the number of primary windings to the number of secondary windings of the transformer T1 is transmitted from the secondary winding to the primary winding of the transformer T1. Similarly, power of a voltage corresponding to the ratio of the number of primary windings to the number of secondary windings of the transformer T2 is transmitted from the secondary winding to the primary winding of the transformer T2.

[0107] The power transmitted to the primary winding of the transformer T1 is stored in the capacitor C1 through the choke coil L2 and the switching element Q6. Also, the power transmitted to the primary winding of the transformer T2 is stored in the capacitor C4 through the choke coil L3 and the switching element Q11.

[0108] As described above, the choke coil L1 stores power before the period A, and current flows between one end and the other end of the choke coil L1 through the positive voltage terminal of the full-wave rectifier circuit 40, the switching element Q1 of the full-wave rectifier circuit 40, the AC power supply Vi, the switching element Q4 of the full-wave rectifier circuit 40, the negative voltage terminal of the full-wave rectifier circuit 40, and the switching elements Q5, Q6, Q11, Q12. Due to the operation of the isolated switching power supply device 3 described above, the power stored in the choke coil L1 is released and supplied to the AC power supply Vi for regeneration.

[0109] When regenerating by supplying power from the battery BAT to the AC power supply Vi, when the operation of the isolated switching power supply device 3 shifts from the period A shown in FIG. 3 to the period B, as shown in FIGS. 4B and 5, the power factor improvement / inverter control circuit 46 controls the switching elements Q1 to Q4 for the rectifying operation, and further controls the states of the switching elements Q5 to Q16. As a result, the switching elements Q5, Q6, Q8, Q9, Q10, Q12, Q13, Q15 are turned on, and the switching elements Q7, Q11, Q14, Q16 are turned off. That is, the switching elements Q8, Q9, Q10, Q15 are turned on from the off state, and the switching elements Q11, Q16 are turned off from the on state.

[0110] A current flows from the positive voltage terminal of the battery BAT through the switching element Q13, the choke coil L4, the secondary winding of the transformer T1, the capacitor C6, the switching element Q15, the choke coil L15, the secondary winding of the transformer T2, and the capacitor C8 to the negative voltage terminal. Electric power of a voltage corresponding to the ratio of the number of turns of the primary winding and the number of turns of the secondary winding of the transformer T1 is transmitted to the primary side of the transformer T1.

[0111] The transmitted electric power is stored in the capacitor C1 through the choke coil L2 and the switching element Q6. Electric power of a voltage corresponding to the ratio of the number of turns of the primary winding and the number of turns of the secondary winding of the transformer T2 is transmitted to the primary side of the transformer T2. The transmitted electric power is stored in the capacitor C3 through the choke coil L3 and the switching element Q10.

[0112] A current flows between one end and the other end of capacitor C1 through switching element Q5, choke coil L1, the positive voltage terminal of full-wave rectifier circuit 40, switching element Q1 of full-wave rectifier circuit 40, AC power supply Vi, switching element Q4 of full-wave rectifier circuit 40, the negative voltage terminal of full-wave rectifier circuit 40, switching element Q8, and capacitor C2. Also, a current flows between one end and the other end of capacitor C3 through switching element Q9, choke coil L1, the positive voltage terminal of full-wave rectifier circuit 40, switching element Q1 of full-wave rectifier circuit 40, AC power supply Vi, switching element Q4 of full-wave rectifier circuit 40, the negative voltage terminal of full-wave rectifier circuit 40, switching element Q12, and capacitor C4. As a result, a current flows through choke coil L1, power is stored in choke coil L1, and the power stored in capacitors C1 and C3 is supplied to and regenerated by AC power supply Vi.

[0113] When supplying power from battery BAT to AC power supply Vi for regeneration, when the operation of isolated switching power supply device 3 shifts from period B to period C as shown in FIG. 3, as shown in FIGS. 4C and 5, power factor improvement / inverter control circuit 46 controls switching elements Q1 to Q4 for rectification operation, and further controls the states of switching elements Q5 to Q16. As a result, switching elements Q7, Q8, Q9, Q10, Q14, Q15 turn ON, and switching elements Q5, Q6, Q10, Q11, Q12, Q13 turn OFF. That is, switching elements Q7, Q14 change from the OFF state to the ON state, and switching elements Q6, Q13, Q5, Q12 change from the ON state to the OFF state.

[0114] A current flows from the positive voltage terminal of the battery BAT, through the capacitor C3, the secondary winding of the transformer T1, the choke coil L4, the switching elements Q14, Q15, the choke coil L5, the secondary winding of the transformer T2, and the switching element Q8, to the negative voltage terminal of the battery BAT. As a result, power of a voltage corresponding to the ratio of the number of primary windings to the number of secondary windings of the transformers T1 and T2 is transmitted from the secondary winding of the transformer T1 and the secondary winding of the transformer T2 to the primary winding of the transformer T1 and the primary winding of the transformer T2.

[0115] In the primary winding of the transformer T1, a current flows through the capacitor C2, the switching element Q7, and the choke coil L2, and the power transmitted to the primary winding of the transformer T1 is stored in the capacitor C2. Also, in the primary winding of the transformer T2, a current flows through the choke coil L3, the switching element Q10, and the capacitor C3, and the power transmitted to the primary winding of the transformer T2 is stored in the capacitor C3.

[0116] A current flows between one end and the other end of the choke coil L1 through the positive voltage terminal of the full-wave rectifier circuit 40, the switching element Q1 included in the full-wave rectifier circuit 40, the AC power supply Vi, the switching element Q4 of the full-wave rectifier circuit 40, the negative voltage terminal of the full-wave rectifier circuit 40, and the switching elements Q4, Q7, Q8, Q9, Q10. As a result, the power stored in the choke coil L1 is released, supplied to the AC power supply Vi, and regenerated.

[0117] When regenerating by supplying power from the battery BAT to the AC power supply Vi, when the operation of the isolated switching power supply device 3 shifts from the period C shown in FIG. 3 to the period D, as shown in FIGS. 4D and 5, the power factor improvement / inverter control circuit 46 controls the switching elements Q1 to Q4 for the rectification operation and further controls the states of the switching elements Q5 to Q16. Thereby, the power factor improvement / inverter control circuit 46 controls the states of Q5 to Q16. As a result, the switching elements Q5, Q7, Q8, Q9, Q11, Q14, Q16 are turned on, and Q6, Q10, Q13, Q15 are turned off. That is, the switching elements Q5, Q11, Q12, Q16 are changed from the off state to the on state, and the switching elements Q10, Q15 are changed from the on state to the off state.

[0118] Current flows from the positive voltage terminal of the battery BAT through the capacitor C5, the secondary winding of the transformer T1, the choke coil L4, the switching element Q14, the capacitor C7, the secondary winding of the transformer T2, the choke coil L5, and the switching element Q16 to the negative voltage terminal of the battery BAT. Thereby, power of a voltage corresponding to the ratio of the number of primary winding turns and the number of secondary winding turns of the transformers T1 and T2 is transmitted from the secondary windings of the transformers T1 and T2 to the primary windings of the transformers T1 and T2.

[0119] Furthermore, current flows from the other end of the primary winding of the transformer T1 through the capacitor C2, the switching element Q7, and the choke coil L2 to one end of the primary winding of the transformer T1, and power is accumulated in the capacitor C2. Also, current flows from the other end of the primary winding of the transformer T2 through the capacitor C4, the switching element Q11, and the choke coil L3 to one end of the primary winding of the transformer T1, and power is accumulated in the capacitor C4.

[0120] As described above, power is stored in capacitors C1, C2, C3, and C4, and due to the power stored in capacitors C1, C2, C3, and C4, currents flow between switching elements Q5, Q8, Q9, Q12, choke coil L1, the positive voltage terminal of full-wave rectifier circuit 40, switching element Q1 of full-wave rectifier circuit 40, AC power supply Vi, switching element Q4 of full-wave rectifier circuit 40, the negative voltage terminal of full-wave rectifier circuit 40, and switching elements Q8, Q12. As a result, power is supplied from battery BAT to AC power supply Vi, regenerated, and power is stored in choke coil L1.

[0121] By repeating the operations in periods A to D described above, isolated switching power supply device 3 supplies the power of voltage value Vo stored in battery BAT to AC power supply Vi and regenerates it.

[0122] Frequency control circuit 44 adjusts the frequency of reference frequency signal fsw based on the voltage value Vo of load Lo or battery BAT so that the voltage value Vo of load Lo or battery BAT becomes a predetermined value (specified value). The reference frequency signal fsw whose frequency is adjusted in this way is output to power factor correction / inverter control circuit 46, and power factor correction / inverter control circuit 46 sets it as the switching frequency in current resonance half-bridge circuits 20, 22. Further, the voltage value of the power rectified by full-wave rectifier circuit 40 and the current value Iin of the power flowing through choke coil L1 are input to power factor correction / inverter control circuit 46 with reference frequency signal fsw. Further, the voltage values (VC1 + VC2) across capacitors C1, C2 and the voltage values (VC3 + VC4) across capacitors C3, C4 are input to power factor correction / inverter control circuit 46 with reference frequency signal fsw.

[0123] The power factor improvement / inverter control circuit 46 controls the timing at which the switching elements Q6, Q7, Q10, and Q11 are turned on or off so that the phase of the waveform of the AC power supply Vi rectified by the full-wave rectifier circuit 40 is the same as the phase of the waveform of the current value Iin. Further, the power factor improvement / inverter control circuit 46 controls the timing at which the switching elements Q6, Q7, Q10, and Q11 are turned on or off so that the voltage values (VC1 + VC2) and (VC3 + VC4) become a specified value.

[0124] When regenerating power from the battery BAT to the AC power supply Vi, the frequency control circuit 44 generates a reference frequency signal fsw having the same frequency as the resonance frequency of the resonance circuit formed by the choke coils L2 and L4, the capacitors C1, C2, C5, and C6, and the transformer T1. As shown in FIG. 5, the power factor improvement / inverter control circuit 46 turns on or off the switching elements Q5, Q6, Q7, Q8, Q9, Q10, Q11, and Q12 so as to match the phase of the waveform of the current value Iin of the choke coil L1 with the phase of the waveform of the voltage value at the positive voltage terminal of the full-wave rectifier circuit 40. By matching the phase of the waveform of the current value Iin of the choke coil L1 with the phase of the waveform of the voltage value at the positive voltage terminal of the full-wave rectifier circuit 40, the power factor of the power supplied from the isolated switching power supply device 3 to the load Lo or the battery BAT is improved.

[0125] The technical effects achieved by the isolated switching power supply devices 2 and 3 will be further described. An isolated switching power supply device such as the isolated switching power supply devices 2 and 3 has a configuration in which the circuit on the power supply side (primary side) and the circuit on the side of the load Lo or the battery BAT (secondary side) are isolated by a transformer. In such an isolated switching power supply device, the choke coil is connected to the primary side of the transformer. In such a configuration, whether power is supplied from the power supply to the load Lo or the operation of supplying power to the battery BAT for charging is performed, when power is transmitted between the choke coil and the primary winding of the transformer, due to the leakage inductance generated on the primary side of the transformer, the value of the current flowing through the choke coil is limited. As a result of the current value flowing through the choke coil being limited in this way, a surge voltage is generated in the choke coil. Therefore, in a general isolated-side switching power supply device, a surge suppression circuit such as a switch snubber circuit is required so that a surge voltage is not applied to the switching element.

[0126] On the other hand, the isolated switching power supply devices 2 and 3 according to the present disclosure have a configuration in which capacitors C1, C2, C3, and C4 are connected in series with the choke coil L1. In such a configuration, whether the operation of supplying power from the power supply to the load Lo is performed or the operation of regenerating power from the battery BAT to the power supply is performed, current can flow without limitation between the choke coil L1 and the capacitors C1, C2, C3, and C4. Therefore, the generation of a surge voltage in the choke coil L1 can be suppressed.

[0127] Furthermore, since the capacitors C1, C2, C5, and C6, the choke coil L2, the transformer T1, and the choke coil L4 form a resonance circuit, the current resonance half-bridge circuit 20 includes a resonance circuit. Also, since the capacitors C3, C4, C7, and C8, the choke coil L3, the transformer T2, and the choke coil L5, and the capacitors C7 and C8 form a resonance circuit, the current resonance half-bridge circuit 22 also includes a resonance circuit.

[0128] If the resonance frequencies of the resonance circuits formed in the current resonance half-bridge circuits 20 and 22 are made the same, and power switched by a reference frequency signal fsw having the same frequency as the resonance frequency is supplied to these resonance circuits, then whether the operation of supplying power from the power supply to the load Lo or the operation of regenerating power from the battery BAT to the power supply is performed, the waveform of the current flowing through the switching elements Q5 to Q16 becomes a sine wave shape with a slower rise than a rectangle. Compared with the case where the waveform of the current flowing through the switching elements Q5 to Q16 is a rectangular wave shape, when the waveform of the current flowing through the switching elements Q5 to Q16 is a sine wave shape, the losses generated in these switching elements Q5 to Q16 are reduced.

[0129] Also, the power factor improvement / inverter control circuit 46 receives the input of the voltage value of the positive voltage terminal of the full-wave rectifier circuit 40, the current value Iin of the choke coil L1, the sum value (Vc1 + Vc2) of the voltage value Vc1 of the capacitor C1 and the voltage value Vc2 of the capacitor C2, and the sum value (Vc3 + Vc4) of the voltage value Vc3 of the capacitor C3 and the voltage value Vc4 of the capacitor C4. The frequencies of the waveforms of the sum values (Vc1 + Vc2) and (Vc3 + Vc4) are, for example, about 10 Hz. Based on these input sum values, the power factor improvement / inverter control circuit 46 controls the timing to turn on or off each of the switching elements Q5 to Q16 so that the phases of the waveform of the current value Iin of the choke coil L1 and the waveform of the voltage value of the positive voltage terminal of the full-wave rectifier circuit 40 match, whether the operation of supplying power from the power supply to the load Lo or the operation of regenerating power from the battery BAT to the power supply is performed. Also, the power factor improvement / inverter control circuit 46 controls the timing to turn on or off each of the switching elements Q5 to Q16 so as to stabilize the peak values of these sum values (Vc1 + Vc2) and (Vc3 + Vc4) to a specified value.

[0130] The resonance frequency of the resonance circuit formed in the current resonance half-bridge circuit 20 can be adjusted by adjusting the inductance of the windings of transformer T1, the inductances of choke coils L2 and L4, and the capacitance values of capacitors C1, C2, C5, and C6. Also, the resonance frequency of the resonance circuit formed in the current resonance half-bridge circuit 22 can also be adjusted by adjusting the inductance of the windings of transformer T2, the inductances of choke coils L3 and L5, and the capacitance values of capacitors C3, C4, C7, and C8. That is, it is easy to adjust the resonance frequencies of the resonance circuits formed in the current resonance half-bridge circuits 20 and 22. Therefore, it is easy to match this resonance frequency to the frequency of the reference frequency signal fsw. Conversely, the frequency of the reference frequency signal fsw can also be matched to the resonance frequencies of the resonance circuits formed in the current resonance half-bridge circuits 20 and 22. Therefore, the range of selection of the frequency of the reference frequency signal fsw is wide, and the range of selection of the capacitance values of the choke coils and capacitors included in the current resonance half-bridge circuits 20 and 22 is also wide.

[0131] [Modification Example] Hereinafter, modification examples of the isolated switching power supply devices 2 and 3 will be described. FIGS. 6 to 8 are diagrams illustrating modification examples of the isolated switching power supply devices 2 and 3 according to an embodiment of the present disclosure shown in FIGS. 2 and 4A to 4D.

[0132] As illustrated in FIG. 6, the isolated switching power supply device 4 includes current resonance half-bridge circuits 24 and 26. The current resonance half-bridge circuit 24 has a configuration in which a capacitor C10 is inserted between the source of the switching element Q6 and one end of the primary side winding of the transformer T1. Also, the current resonance half-bridge circuit 26 has a configuration in which a capacitor C11 is inserted between the source of the switching element Q10 and one end of the primary side winding of the transformer T2. By inserting the capacitors C11 and C12 between the sources of the switching elements Q6 and Q10 and one end of the primary sides of the transformers T1 and T2 in this way, the operation of the isolated switching power supply device 4 becomes more stable than that of the isolated switching power supply devices 2 and 3.

[0133] As illustrated in FIG. 7, the isolated switching power supply device 5 includes current resonance half-bridge circuits 28 and 30. The current resonance half-bridge circuit 28 has a configuration in which a capacitor C12 is added between the source of the switching element Q5 and the drain of the switching element Q6 of the current resonance half-bridge circuit 20 of the isolated switching power supply device 3, and between the source of the switching element Q7 and the drain of the switching element Q8. The current resonance half-bridge circuit 30 has a configuration in which a capacitor C13 is added between the source of the switching element Q9 and the drain of the switching element Q10 of the current resonance half-bridge circuit 22, and between the source of the switching element Q11 and the drain of the switching element Q12.

[0134] In other words, the isolated switching power supply device 5 has a configuration in which a capacitor C12 is added in parallel to the capacitors C1 and C2 connected in series in the isolated switching power supply device 3, and a capacitor C13 is added in parallel to the capacitors C3 and C4 connected in series. As described above, the resonance frequencies of the current resonance half-bridge circuits 28 and 30 of the isolated switching power supply device 4, to which the capacitors C10 and C11 are added to the isolated switching power supply device 3, become lower, and its operation becomes more stable than that of the isolated switching power supply device 3.

[0135] As illustrated in FIG. 8, the isolated switching power supply device 6 has a configuration in which the current resonance half-bridge circuits 20 and 22 of the isolated switching power supply device 3 are replaced by half-bridge circuits 32 and 34, and the frequency control circuit 44 is omitted. The half-bridge circuits 32 and 34 have a configuration in which the choke coils L2 to L5 are omitted from the current resonance half-bridge circuits 20 and 22 of the isolated switching power supply device 3. A resonance circuit is formed in the current resonance half-bridge circuits 32 and 34 in the same manner as in the current resonance half-bridge circuits 20 and 22. However, since the choke coils L2 to L5 are omitted, the resonance frequency is fixed, and control of the switching frequency by the frequency control circuit 44 is not required. Therefore, the configuration of the isolated switching power supply device 5 is simpler than that of the isolated switching power supply device 3, and its control can also be simplified.

[0136] As described above, the control of the current resonance half-bridge circuits 20 and 22 by the power factor improvement / inverter control circuit 46 and the frequency control circuit 44 can be realized by a program executed in the information processing device 7. On the other hand, these components may be realized by dedicated hardware, or may be realized by an appropriate combination of hardware and software (program) executed in the information processing device 7.

[0137] [Information Processing Device That Can Be Used in the Implementation of the Embodiment of the Present Disclosure] Note that all or part of the processing for controlling the power factor improvement / inverter control circuit 46 and the frequency control circuit 44 of the isolated switching power supply devices 3 and 4 according to the embodiments of the present disclosure may be performed by the information processing device (computer) 7 described below. FIG. 9 is a diagram illustrating the configuration of an information processing device 7 that can implement all or part of the functions of the components of an isolated switching power supply device according to the present disclosure. As illustrated in FIG. 9, the information processing device 7 includes a CPU (Central Processing Unit) 700, a main storage device 702, an auxiliary storage device 704, and an interface (IF) 706 that are interconnected via a bus so as to be able to input and output information. However, the information processing device 7 may include hardware components other than those shown in FIG. 9, and the configuration of the information processing device 7 is not limited to the configuration shown in FIG. 9.

[0138] The CPU 700 executes instruction commands included in a program that is executed by the information processing device 7 and is required for the processing of the power factor improvement / inverter control circuit 46 and the frequency control circuit 44. The main storage device 702 includes storage elements such as, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory), and temporarily stores data used by the CPU 700 to execute a program.

[0139] The auxiliary storage device 704 includes, for example, a non-volatile storage device such as a flash memory, and stores programs executed by the CPU 700 in the medium to long term. Note that the programs stored in the auxiliary storage device 704 can be provided and distributed as products stored in a non-transitory computer-readable medium such as a magnetic storage medium, a CD, and a DVD.

[0140] The IF device 706 provides an interface for input and output of information between a current sensor that measures the current value Iin flowing through the choke coil L1, a voltage sensor that measures the voltages of the capacitors C3 and C4, and an oscillation circuit (not shown) that generates a reference frequency signal fsw.

[0141] As described above, the control processing by the power factor improvement / inverter control circuit 46 and the frequency control circuit 44 of the isolated switching power supply devices 3 and 4 can be realized by a program executed in the information processing device 7. On the other hand, these components may be realized by dedicated hardware, or may be realized by an appropriate combination of hardware and software (program) executed in the information processing device 7.

[0142] The following forms are possible in the present application, but are not limited thereto. [Appendix 1] A power supply device comprising: a first coil having one end connected to a terminal of a first power supply with a first voltage polarity; a first active element and a second active element having one end connected to the other end of the first coil; a third active element and a fourth active element having the other end connected to a terminal of the first power supply with a second voltage polarity; a first half-bridge circuit including a first transformer; a second half-bridge circuit including a second transformer; and a control circuit configured to control the first half-bridge circuit and the second half-bridge circuit so as to supply power from the first power supply to a load or to regenerate power from a second power supply instead of the load to the first power supply. The first half-bridge circuit includes: a fifth active element having one end connected to the other end of the first active element and the other end connected to one end of a primary winding of the first transformer and one end of a primary winding of the second transformer; a sixth active element having one end connected to the other end of the fifth active element and the other end connected to one end of the third active element; a ninth active element having one end connected to a terminal of the load with the first voltage polarity and the other end connected to one end of a secondary winding of the first transformer; a tenth active element having one end connected to one end of the secondary winding of the first transformer and the other end connected to the second half-bridge circuit; a first capacitor having one end connected to one end of the fifth active element and the other end connected to the other end of the primary winding of the first transformer; a second capacitor having one end connected to the other end of the primary winding of the first transformer and the other end connected to the other end of the sixth active element; a third capacitor having one end connected to one end of the ninth active element and the other end connected to the other end of the secondary winding of the first transformer; and a fourth capacitor having one end connected to the other end of the secondary winding of the first transformer and the other end connected to the other end of the tenth active element.The second half-bridge circuit includes a seventh active element having one end connected to the other end of the second active element and the other end connected to one end of the primary winding of the first transformer and one end of the primary winding of the second transformer; an eighth active element having one end connected to the other end of the seventh active element and the other end connected to one end of the fourth active element; an eleventh active element having one end connected to the source of the tenth active element and the other end connected to the other end of the secondary winding of the second transformer; a twelfth active element having one end connected to the other end of the eleventh active element and the other end connected to the terminal of the load having the second voltage polarity; a fifth capacitor having one end connected to one end of the seventh active element and the other end connected to the other end of the primary winding of the second transformer; a sixth capacitor having one end connected to the other end of the primary winding of the second transformer and the other end connected to the other end of the eighth active element; a seventh capacitor having one end connected to one end of the eleventh active element and the other end connected to the other end of the secondary winding of the second transformer; and an eighth capacitor having one end connected to the other end of the secondary winding of the second transformer and the other end connected to the other end of the twelfth active element. [Appendix 2] The control circuit is a power supply device that controls the second active element and the third active element to be simultaneously in an ON state or an OFF state, the fifth active element and the ninth active element to be simultaneously in an ON state or an OFF state, the sixth active element and the tenth active element to be simultaneously in an ON state or an OFF state, the seventh active element and the eleventh active element to be simultaneously in an ON state or an OFF state, the eighth active element and the twelfth active element to be simultaneously in an ON state or an OFF state, and the sixth active element and the tenth active element, and the first active element and the fourth active element to be alternately in an ON state or an OFF state so that the first active element and the fourth active element are simultaneously in a conducting state (ON state) where conduction occurs between one end and the other end or a non-conducting state (OFF state) where no conduction occurs between one end and the other end. [Appendix 3] When power is supplied from the first power supply to the load connected between one end of the ninth active element and the other end of the twelfth active element, while power is being stored in the first coil, the control circuit turns on the first active element, the fourth active element, the fifth active element, the eighth active element, the ninth active element, and the twelfth active element, and turns off the second active element, the third active element, the sixth active element, the seventh active element, the tenth active element, and the eleventh active element. A power supply device for controlling as such. [Appendix 4] When power is supplied from the first power supply to the load connected between one end of the ninth active element and the other end of the twelfth active element, while power is being stored in the first coil, the control circuit turns on the second active element, the third active element, the sixth active element, the seventh active element, the tenth active element, and the eleventh active element, and turns off the first active element, the fourth active element, the fifth active element, the eighth active element, the ninth active element, and the twelfth active element. A power supply device for controlling as such. [Appendix 5] When power is supplied from the first power supply to the load connected between one end of the ninth active element and the other end of the twelfth active element, while power is being released from the first coil, the control circuit turns on the first active element, the second active element, the third active element, the fourth active element, the sixth active element, the eighth active element, the tenth active element, and the twelfth active element so that conduction is established between one end and the other end, and turns off the fifth active element, the seventh active element, the ninth active element, and the eleventh active element so that non-conduction is established between one end and the other end. A power supply device for controlling as such. [Appendix 6] When regenerating power from the second power supply, where the terminal of the first voltage polarity is connected to one end of the ninth active element and the terminal of the second voltage polarity is connected to the other end of the twelfth active element, to the first power supply, while storing power in the first coil, the control circuit sets the first active element, the second active element, the third active element, the fourth active element, the sixth active element, the eighth active element, the tenth active element, and the twelfth active element to an ON state in which conduction is established between one end and the other end, and sets the fifth active element, the seventh active element, the ninth active element, and the eleventh active element to an OFF state in which conduction is not established between one end and the other end. A power supply device that controls accordingly. [Appendix 7] When regenerating power from the second power supply, where the terminal of the first voltage polarity is connected to one end of the ninth active element and the terminal of the second voltage polarity is connected to the other end of the twelfth active element, to the first power supply, while discharging power from the first coil, the control circuit sets the second active element, the third active element, the sixth active element, the seventh active element, the tenth active element, and the eleventh active element to the ON state, and controls to set the first active element, the fourth active element, the fifth active element, the eighth active element, the ninth active element, and the twelfth active element to the OFF state. [Appendix 8] The first half-bridge circuit further includes a second coil with both ends connected between the other end of the fifth active element and one end of the primary winding of the first transformer, and a fourth coil with both ends connected between the other end of the ninth active element and one end of the secondary winding of the first transformer. The second half-bridge circuit further includes a third coil with both ends connected between the other end of the seventh active element and one end of the primary winding of the second transformer, and a fifth coil with both ends connected between the other end of the eleventh active element and one end of the primary winding of the second transformer. A power supply device. [Appendix 9] The first half-bridge circuit and the second half-bridge circuit are power supply devices that are current resonance half-bridge circuits. Combinations of each aspect according to the appendices of the present disclosure, or any combination of each element described in each perspective and embodiment (including non-selection of some elements), can obviously be made by those skilled in the art at any time according to the basic concept of the present disclosure.

[0143] Note that the disclosures of the above-cited patent documents and the like are incorporated herein by reference. Within the scope of all disclosures (including the claims), further modifications and adjustments of the embodiments or examples can be made based on the basic technical idea. Also, within the scope of all disclosures, various combinations or selections (including partial deletion) of various disclosure elements (including each element of each claim, each element of the embodiments or examples, each element of each drawing, etc.) are possible. That is, the present disclosure naturally includes all disclosures including the claims and various deformations and corrections that those skilled in the art could make according to the technical idea. In particular, for the numerical ranges described in this document, any numerical value or small range included within the range should be construed as specifically described even without separate description. Furthermore, the disclosure matters of the above patent documents are, if necessary, incorporated into the present disclosure as part of the present disclosure and can be used in combination with the description matters of this document, in accordance with the spirit of the present disclosure, considering part or all of them as included in the disclosure matters of this application.

Explanation of Reference Signs

[0144] 1 - 6 Insulated Switching Power Supply Device 20, 22, 24, 26, 28, 30, 32, 34 Current Resonant Half - Bridge Circuit 32, 34 Half - Bridge Circuit 40 Full - Wave Rectifier Circuit 44 Frequency Control Circuit 46 Power Factor Improvement / Inverter Control Circuit 7 Information Processing Device 700 CPU 702 Main Memory Device 704 Auxiliary Storage Device 706 IF Device Q1 - Q4 Switching Elements Q5 Switching Element (First Active Element) Q6 Switching Element (Fifth Active Element) Q7 Switching Element (Sixth Active Element) Q8 Switching Element (Third Active Element) Q9 Switching Element (Second Active Element) Q10 Switching Element (Seventh Active Element) Q11 Switching Element (Eighth Active Element) Q12 Switching Element (Fourth Active Element) Q13 Switching Element (Ninth Active Element) Q14 Switching Element (Tenth Active Element) Q15 Switching Element (Eleventh Active Element) Q16 Switching Element (Twelfth Active Element) C1~C8 Capacitors (First to Eighth Capacitors) L1 Choke Coil L2~L5 Choke Coil L (Second to Fifth Coils) n1~n13 Nodes T1,T2 Transformers Ei DC Power Supply Vi AC Power Supply Lo Load BAT Battery

Claims

1. A first coil having one end connected to a terminal of a first voltage polarity of a first power supply, a first active element and a second active element having one end connected to the other end of the first coil, a third active element and a fourth active element having the other end connected to a terminal of a second voltage polarity of the first power supply, a first half-bridge circuit including a first transformer, a second half-bridge circuit including a second transformer, and a control circuit configured to control the first half-bridge circuit and the second half-bridge circuit so as to supply power from the first power supply to a load or to regenerate power from a second power supply instead of the load to the first power supply. The first half-bridge circuit includes: A fifth active element having one end connected to the other end of the first active element and the other end connected to one end of a primary winding of the first transformer and one end of a primary winding of the second transformer; A sixth active element having one end connected to the other end of the fifth active element and the other end connected to one end of the third active element; A ninth active element having one end connected to a terminal of a first voltage polarity of the load and the other end connected to one end of a secondary winding of the first transformer; A tenth active element having one end connected to one end of the secondary winding of the first transformer and the other end connected to the second half-bridge circuit; A first capacitor having one end connected to one end of the fifth active element and the other end connected to the other end of the primary winding of the first transformer; A second capacitor having one end connected to the other end of the primary winding of the first transformer and the other end connected to the other end of the sixth active element; A third capacitor having one end connected to one end of the ninth active element and the other end connected to the other end of the secondary winding of the first transformer; A fourth capacitor having one end connected to the other end of the secondary winding of the first transformer and the other end connected to the other end of the tenth active element. The first half-bridge circuit further includes: The second half-bridge circuit includes: A seventh active element having one end connected to the other end of the second active element and the other end connected to one end of a primary winding of the first transformer and one end of a primary winding of the second transformer; An eighth active element having one end connected to the other end of the seventh active element and the other end connected to one end of the fourth active element; An eleventh active element having one end connected to the source of the tenth active element and the other end connected to the other end of a secondary winding of the second transformer. A twelfth active element having one end connected to the other end of the eleventh active element and the other end connected to the terminal of the load having the second voltage polarity; A fifth capacitor having one end connected to one end of the seventh active element and the other end connected to the other end of the primary winding of the second transformer; A sixth capacitor having one end connected to the other end of the primary winding of the second transformer and the other end connected to the other end of the eighth active element; A seventh capacitor having one end connected to one end of the eleventh active element and the other end connected to the other end of the secondary winding of the second transformer; An eighth capacitor having one end connected to the other end of the secondary winding of the second transformer and the other end connected to the other end of the twelfth active element A power supply device comprising. **Claim 2** The control circuit Causes the first active element and the fourth active element to be in an ON state in which conduction is established between one end and the other end or an OFF state in which non-conduction is established between one end and the other end at the same time, Causes the second active element and the third active element to be in an ON state or an OFF state at the same time, Causes the fifth active element and the ninth active element to be in an ON state or an OFF state at the same time, Causes the sixth active element and the tenth active element to be in an ON state or an OFF state at the same time, Causes the seventh active element and the eleventh active element to be in an ON state or an OFF state at the same time, Causes the eighth active element and the twelfth active element to be in an ON state or an OFF state at the same time, Causes the sixth active element and the tenth active element, and the first active element and the fourth active element to be alternately in an ON state or an OFF state The power supply device according to claim 1, which controls. **Claim 3** When power is supplied from the first power supply to the load connected between one end of the ninth active element and the other end of the twelfth active element, while power is being stored in the first coil, the control circuit Turns on the first active element, the fourth active element, the fifth active element, the eighth active element, the ninth active element, and the twelfth active element, Turns off the second active element, the third active element, the sixth active element, the seventh active element, the tenth active element, and the eleventh active element The power supply device according to claim 2, which controls in such a manner. **Claim 4** When supplying power from the first power supply to the load connected between one end of the ninth active element and the other end of the twelfth active element, while storing power in the first coil, the control circuit sets the second active element, the third active element, the sixth active element, the seventh active element, the tenth active element, and the eleventh active element to the ON state, and sets the first active element, the fourth active element, the fifth active element, the eighth active element, the ninth active element, and the twelfth active element to the OFF state. The power supply device according to claim 2, which controls as described above.

5. When supplying power from the first power supply to the load connected between one end of the ninth active element and the other end of the twelfth active element, while discharging power from the first coil, the control circuit sets the first active element, the second active element, the third active element, the fourth active element, the sixth active element, the eighth active element, the tenth active element, and the twelfth active element to the ON state where conduction is established between one end and the other end, and sets the fifth active element, the seventh active element, the ninth active element, and the eleventh active element to the OFF state where non - conduction is established between one end and the other end, and controls as such. The power supply device according to claim 2.

6. When regenerating power from the second power supply, to which a terminal of a first voltage polarity is connected to one end of the ninth active element and a terminal of a second voltage polarity is connected to the other end of the twelfth active element, to the first power supply, while storing power in the first coil, the control circuit sets the first active element, the second active element, the third active element, the fourth active element, the sixth active element, the eighth active element, the tenth active element, and the twelfth active element to the ON state where conduction is established between one end and the other end, and sets the fifth active element, the seventh active element, the ninth active element, and the eleventh active element to the OFF state where non - conduction is established between one end and the other end, and controls as such. The power supply device according to claim 2.

7. When regenerating power from the second power supply, to which a terminal of a first voltage polarity is connected to one end of the ninth active element and a terminal of a second voltage polarity is connected to the other end of the twelfth active element, to the first power supply, while discharging power from the first coil, the control circuit Turn on the second active element, the third active element, the sixth active element, the seventh active element, the tenth active element, and the eleventh active element. Turn off the first active element, the fourth active element, the fifth active element, the eighth active element, the ninth active element, and the twelfth active element. The power supply device according to claim 2, wherein control is performed as described above.

8. The first half-bridge circuit includes: a second coil having both ends connected between the other end of the fifth active element and one end of the primary winding of the first transformer; a fourth coil having both ends connected between the other end of the ninth active element and one end of the secondary winding of the first transformer. The power supply device further includes: The second half-bridge circuit includes: a third coil having both ends connected between the other end of the seventh active element and one end of the primary winding of the second transformer; a fifth coil having both ends connected between the other end of the eleventh active element and one end of the primary winding of the second transformer. The power supply device according to claim 1, further comprising:

9. The first half-bridge circuit and the second half-bridge circuit are current-resonant half-bridge circuits. The power supply device according to claim 8.

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