Bidirectional DC conversion circuit, bidirectional DC converter and electrical equipment

Abstract

The present invention relates to a bidirectional DC conversion circuit, a bidirectional DC converter and an electrical device, including a low voltage input and output device, a buck-boost device, a high voltage input and output device, an anti-reverse device, a switching power supply and a control device; after the low voltage input and output device or the high voltage input and output device is powered, it can supply power to the switching power supply, so that the switching power supply provides voltage to the control device; the control device controls the buck-boost device to work, so that there is low voltage electricity at the low voltage end of the buck-boost device and high voltage electricity at the high voltage end of the buck-boost device, the anti-reverse device between the low voltage end of the buck-boost device and the high voltage end of the buck-boost device is disconnected, and the high voltage end of the buck-boost device supplies power to the switching power supply to maintain the current working mode of the buck-boost device. The technical solution of the present invention can reduce the number of switching power supplies, thereby reducing the electrical components of the DC bidirectional converter, reducing the circuit complexity, and improving the integration of the DC bidirectional converter.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a bidirectional direct current conversion circuit, a bidirectional direct current converter and electrical equipment. Background Art

[0002] At present, the two voltage levels of DC microgrid bus are DC750V and DC400V. In many applications, it is necessary to ensure that the use environment is not restricted by the voltage level. Therefore, the DC bidirectional converter of DC microgrid power distribution can be used to provide the corresponding voltage to the DC microgrid bus.

[0003] In the prior art, two switching power supplies need to be set up to ensure that when either end of DC750V or DC400V is powered, the switching power supply is powered, and then the control and drive circuits are powered, so that the DC bidirectional converter can work normally.

[0004] However, due to the use of two switching power supplies, the DC bidirectional converter has more electrical components and a relatively complex circuit, resulting in a low integration level of the DC bidirectional converter. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a bidirectional DC conversion circuit, a bidirectional DC converter and an electrical device to solve the problem of low integration of DC bidirectional converters in the prior art.

[0006] To achieve the above objectives, the present invention provides a bidirectional DC conversion circuit, including a low voltage input and output device, a step-up and step-down device, a high voltage input and output device, an anti-reverse device, a switching power supply and a control device;

[0007] The low-voltage input-output device is connected to the low-voltage end of the step-up / step-down device;

[0008] The high-voltage input-output device is connected to the high-voltage end of the step-up / step-down device;

[0009] The low voltage end of the buck-boost device is connected to the input end of the switching power supply through the anti-reverse device;

[0010] The high voltage end of the buck-boost device is connected to the input end of the switching power supply;

[0011] The output end of the switching power supply is connected to the control device;

[0012] The control device is also connected to the control end of the buck-boost device;

[0013] After the low-voltage input-output device or the high-voltage input-output device is powered, it can supply power to the switching power supply, so that the switching power supply provides voltage to the control device;

[0014] The control device controls the operation of the buck-boost device so that low voltage electricity exists at the low voltage end of the buck-boost device and high voltage electricity exists at the high voltage end of the buck-boost device, the anti-reverse device between the low voltage end of the buck-boost device and the high voltage end of the buck-boost device is disconnected, and the high voltage end of the buck-boost device supplies power to the switching power supply to maintain the current working mode of the buck-boost device.

[0015] Further, in the above-mentioned bidirectional DC conversion circuit, the low-voltage input-output device includes a low-voltage input-output port and a low-voltage side filter;

[0016] The low voltage input and output port is connected to the low voltage side filter;

[0017] The low-voltage side filter is connected to the low-voltage end of the buck-boost device.

[0018] Furthermore, in the bidirectional DC conversion circuit described above, the high-voltage input-output device includes a high-voltage input-output port and a high-voltage side filter;

[0019] The high voltage input and output port is connected to the high voltage side filter;

[0020] The high-voltage side filter is connected to the high-voltage end of the buck-boost device.

[0021] Furthermore, in the above-mentioned bidirectional DC conversion circuit, the buck-boost device includes a first capacitor, an inductor, a first drive switch, a second drive switch and a second capacitor;

[0022] The positive electrode of the first capacitor and the negative electrode of the first capacitor serve as the low voltage end of the buck-boost device;

[0023] The positive electrode of the second capacitor and the negative electrode of the second capacitor serve as the high voltage end of the buck-boost device;

[0024] The positive electrode of the first capacitor is connected to the first end of the inductor;

[0025] The second end of the inductor is connected to the first end of the first drive switch and the second end of the second drive switch respectively;

[0026] The second end of the first driving switch is connected to the positive electrode of the second capacitor;

[0027] The first end of the second driving switch is connected to the negative electrode of the first capacitor and the negative electrode of the second capacitor respectively;

[0028] The third end of the first drive switch and the third end of the second drive switch serve as control ends of the buck-boost device.

[0029] Furthermore, in the above-mentioned bidirectional DC conversion circuit, both the first drive switch and the second drive switch are metal-oxide-semiconductor field effect transistors.

[0030] Furthermore, in the above-mentioned bidirectional DC conversion circuit, the anti-reverse device includes a first anti-reverse diode and a second anti-reverse diode;

[0031] The positive electrode of the first capacitor is connected to the positive electrode of the first anti-reverse diode;

[0032] The cathode of the first anti-reverse diode is connected to the anode port of the input end of the switching power supply;

[0033] The negative electrode port of the input end of the switching power supply is connected to the positive electrode of the second anti-reverse diode;

[0034] The cathode of the second anti-reverse diode is connected to the cathode of the first capacitor.

[0035] Furthermore, in the above-mentioned bidirectional DC conversion circuit, the control device includes a control chip and a drive chip;

[0036] The switching power supply, the control chip, and the driving chip are connected in sequence;

[0037] The driving chip is connected to the control end of the buck-boost device.

[0038] The present invention also provides a bidirectional DC converter, which is provided with the bidirectional DC conversion circuit as described in any one of the above items.

[0039] The present invention also provides an electrical device provided with the bidirectional DC converter as described above.

[0040] Furthermore, in the above-mentioned electrical equipment, the electrical equipment is an air conditioner.

[0041] The bidirectional DC conversion circuit, bidirectional DC converter and electrical equipment of the present invention are provided with a switching power supply, the low voltage end of the buck-boost device is connected to the input end of the switching power supply through the anti-reverse device, and the high voltage end of the buck-boost device is connected to the input end of the switching power supply, so that the low voltage end of the buck-boost device and the high voltage end of the buck-boost device are connected by the anti-reverse device, so that after the low voltage input and output device or the high voltage input and output device is powered, both can supply power to the switching power supply, so that the switching power supply provides voltage to the control device; after the control device controls the buck-boost device to work, low voltage electricity exists at the low voltage end of the buck-boost device and high voltage electricity exists at the high voltage end of the buck-boost device, the anti-reverse device between the low voltage end of the buck-boost device and the high voltage end of the buck-boost device is disconnected, and the high voltage end of the buck-boost device supplies power to the switching power supply to maintain the current working mode of the buck-boost device. The technical solution of the present invention can reduce the number of switching power supplies, thereby reducing the electrical components of the DC bidirectional converter, reducing the circuit complexity, and improving the integration of the DC bidirectional converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 It is a structural schematic diagram of a first embodiment of a bidirectional DC conversion circuit of the present invention;

[0044] Figure 2 It is a structural schematic diagram of a second embodiment of a bidirectional DC conversion circuit of the present invention. DETAILED DESCRIPTION

[0045] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0046] Figure 1 FIG. 1 is a schematic diagram of the structure of a bidirectional DC conversion circuit according to a first embodiment of the present invention. Figure 1As shown, the bidirectional DC conversion circuit of this embodiment includes a low voltage input and output device 10, a buck-boost device 11, a high voltage input and output device 12, an anti-reverse device 13, a switch power supply 14 and a control device 15. The low voltage input and output device 10 is connected to the low voltage end of the buck-boost device 11; the high voltage input and output device 12 is connected to the high voltage end of the buck-boost device 11; the low voltage end of the buck-boost device 11 is connected to the input end of the switch power supply 14 through the anti-reverse device 13; the high voltage end of the buck-boost device 11 is connected to the input end of the switch power supply 14; the output end of the switch power supply 14 is connected to the control device 15; and the control device 15 is also connected to the control end of the buck-boost device 11.

[0047] In this embodiment, after the low-voltage input-output device 10 or the high-voltage input-output device 12 is powered, it can supply power to the switching power supply 14, so that the switching power supply 14 provides voltage to the control device 15; the control device 15 controls the buck-boost device 11 to work, so that there is low voltage electricity at the low-voltage end of the buck-boost device 11 and there is high voltage electricity at the high-voltage end of the buck-boost device 11, the anti-reverse device 13 between the low-voltage end of the buck-boost device 11 and the high-voltage end of the buck-boost device 11 is disconnected, and the high-voltage end of the buck-boost device 11 supplies power to the switching power supply 14 to maintain the current working mode of the buck-boost device 11.

[0048] Specifically, the bidirectional DC conversion circuit of this embodiment can operate in two working states:

[0049] Status 1:

[0050] The low-voltage input-output device 10 inputs low-voltage electricity, and the current flows into the switching power supply 14 through the anti-reverse device 13. The switching power supply 14 is powered, and the switching power supply 14 steps down the voltage to the working voltage of the control device 15, and then supplies power to the control device 15. The control device 15 controls the control end of the buck-boost device 11 so that the buck-boost circuit enters the boost mode, and the high-voltage input-output device 12 outputs high-voltage electricity. At the same time, since the high-voltage end of the buck-boost device 11 is connected to the input end of the switching power supply 14, the buck-boost device 11 steps up the low-voltage electricity of the low-voltage input-output device 10. After that, the switching power supply 14 will also be powered. At this time, since there is an anti-reverse device 13 between the low-voltage end of the buck-boost device 11 and the high-voltage end of the buck-boost device 11, the anti-reverse device 13 will not be turned on, that is to say, the high voltage electricity at the high-voltage end of the buck-boost device 11 will not flow to the low-voltage end of the buck-boost device 11. In addition, the low-voltage end of the buck-boost device 11 no longer powers the switching power supply 14, thereby ensuring the normal operation of the bidirectional DC conversion circuit, preventing damage to the bidirectional DC converter, and preventing damage to the electrical equipment connected to the bidirectional DC converter.

[0051] Status 2:

[0052] The high-voltage input-output device 12 inputs high-voltage electricity, and the current flows into the switching power supply 14, the switching power supply 14 is powered, and the switching power supply 14 steps down the voltage to the working voltage of the control device 15, and then supplies power to the control device 15. The control device 15 controls the control end of the buck-boost device 11 so that the buck-boost circuit enters the buck mode, and the low-voltage input-output device 10 outputs low-voltage electricity. At the same time, since the low-voltage end of the buck-boost device 11 is connected to the input end of the switching power supply 14 through the anti-reverse device 13, the buck-boost device 11 steps up the high-voltage electricity of the high-voltage input-output device, and the normal In this case, the switching power supply 14 will also be powered, but since there is an anti-reverse device 13 between the low-voltage end of the buck-boost device 11 and the high-voltage end of the buck-boost device 11, the anti-reverse device 13 will not be turned on, that is to say, the high voltage electricity at the high-voltage end of the buck-boost device 11 will not flow to the low-voltage end of the buck-boost device 11. In addition, the low-voltage end of the buck-boost device 11 cannot power the switching power supply 14, thereby ensuring the normal operation of the bidirectional DC conversion circuit, preventing damage to the bidirectional DC converter, and preventing damage to the electrical equipment connected to the bidirectional DC converter.

[0053] The bidirectional DC conversion circuit of this embodiment is provided with a switching power supply 14, and the low voltage end of the buck-boost device 11 is connected to the input end of the switching power supply 14 through the anti-reverse device 13, and the high voltage end of the buck-boost device 11 is connected to the input end of the switching power supply 14, so that the low voltage end of the buck-boost device and the high voltage end of the buck-boost device 11 are connected by the anti-reverse device 13, so that after the low voltage input-output device 10 or the high voltage input-output device 12 is powered, both can supply power to the switching power supply 14, so that the switching power supply 14 provides voltage to the control device 15; after the control device 15 controls the buck-boost device 11 to work, low voltage electricity exists at the low voltage end of the buck-boost device 11 and high voltage electricity exists at the high voltage end of the buck-boost device 11, the anti-reverse device 13 between the low voltage end of the buck-boost device 11 and the high voltage end of the buck-boost device 11 is disconnected, and the high voltage end of the buck-boost device 11 supplies power to the switching power supply 14 to maintain the current working mode of the buck-boost device 11. By adopting the technical solution of the present invention, the number of switching power supplies 14 can be reduced, thereby reducing the number of electrical components of the DC bidirectional converter, reducing circuit complexity, and improving the integration of the DC bidirectional converter.

[0054] Figure 2 FIG. 1 is a schematic diagram of the structure of a second embodiment of a bidirectional DC conversion circuit according to the present invention. Figure 2As shown, in this embodiment, the low-voltage input-output device 10 includes a low-voltage input-output port and a low-voltage side filter 101; the positive pole VL+ and the negative pole VL- of the low-voltage input-output port are respectively connected to the low-voltage side filter 101; the low-voltage side filter 101 is connected to the low-voltage end of the step-up / step-down device 11. After the external power source powers on the low-voltage input-output device 10 through the low-voltage input-output port, a relatively stable voltage can be obtained after filtering by the low-voltage side filter 101, thereby effectively reducing the grid voltage interference, thereby ensuring normal power supply.

[0055] Similarly, the high-voltage input-output device includes a high-voltage input-output port and a high-voltage side filter 121; the positive pole VH+ and the negative pole VH- of the high-voltage input-output port are respectively connected to the high-voltage side filter 121; the high-voltage side filter 121 is connected to the high-voltage end of the buck-boost device 11. After the external power supply powers on the high-voltage input-output device 12 through the high-voltage input-output port, a relatively stable voltage can be obtained after filtering by the high-voltage side filter 121, thereby effectively reducing the grid voltage interference, thereby ensuring normal power supply.

[0056] like Figure 2 As shown, in this embodiment, the buck-boost device 11 includes a first capacitor C1, an inductor L, a first drive switch Q1, a second drive switch Q2, and a second capacitor C2; the positive electrode C1+ of the first capacitor and the negative electrode C1- of the first capacitor serve as the low voltage end of the buck-boost device 11; the positive electrode C2+ of the second capacitor and the negative electrode C2- of the second capacitor serve as the high voltage end of the buck-boost device 11; the positive electrode C1+ of the first capacitor is connected to the first end of the inductor L; the second end of the inductor L is respectively connected to the first end of the first drive switch Q1 and the second end of the second drive switch Q2; the second end of the first drive switch Q1 is connected to the positive electrode C2+ of the second capacitor; the first end of the second drive switch Q2 is respectively connected to the negative electrode C1- of the first capacitor and the negative electrode C2- of the second capacitor; the third end of the first drive switch Q1 and the third end of the second drive switch Q2 serve as the control end of the buck-boost device 11. Wherein, both the first drive switch Q1 and the second drive switch Q2 are metal-oxide-semiconductor field effect transistors.

[0057] like Figure 2As shown, in this embodiment, the anti-reverse device 13 includes a first anti-reverse diode D1 and a second anti-reverse diode D2; the positive electrode C1+ of the first capacitor is connected to the positive electrode of the first anti-reverse diode D1; the negative electrode of the first anti-reverse diode D1 is connected to the positive electrode port of the input end of the switching power supply 14; the negative electrode port of the input end of the switching power supply 14 is connected to the positive electrode of the second anti-reverse diode D2; the negative electrode of the second anti-reverse diode D2 is connected to the negative electrode C1- of the first capacitor.

[0058] like Figure 2 As shown, the control device 15 includes a control chip 151 and a drive chip 152 ; the switching power supply 14 , the control chip 151 , and the drive chip 152 are connected in sequence; and the drive chip 152 is connected to the control end of the buck-boost device 11 .

[0059] In the bidirectional DC conversion circuit of this embodiment, no matter in which working state, after the bidirectional DC converter works normally, the low voltage end and the high voltage end of the buck-boost device 11 will be connected to the input end of the switching power supply 14 at the same time. At this time, the high voltage end of the buck-boost device 11 is higher than the low voltage end of the buck-boost device 11, and the two anti-reverse diodes cannot be turned on, so that the high voltage end of the buck-boost device 11 can be blocked to affect the low voltage end of the buck-boost device 11, ensuring the normal operation of the bidirectional DC conversion circuit, preventing the converter from not working properly due to the high and low voltages being connected together, damaging the bidirectional DC converter, and damaging electrical equipment. In addition, the power supply of the switching power supply 14 is located after the low voltage side filter 101 and the high voltage side filter 121, which can effectively reduce the interference of the grid voltage, thereby ensuring normal power supply.

[0060] The present invention further provides a bidirectional DC converter, which is provided with the bidirectional DC conversion circuit as described in the above embodiment.

[0061] The present invention further provides an electrical device, which is provided with the bidirectional DC converter as described in the above embodiment. The electrical device of this embodiment is preferably an air conditioner.

[0062] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0063] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0064] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0065] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A bidirectional DC conversion circuit, characterized in that: Including low voltage input and output equipment, step-up and step-down equipment, high voltage input and output equipment, anti-reverse devices, switching power supplies and control equipment; The low-voltage input-output device is connected to the low-voltage end of the step-up / step-down device; The high-voltage input-output device is connected to the high-voltage end of the step-up / step-down device; The low voltage end of the buck-boost device is connected to the input end of the switching power supply through the anti-reverse device; The high voltage end of the buck-boost device is connected to the input end of the switching power supply; The output end of the switching power supply is connected to the control device; The control device is also connected to the control end of the buck-boost device; After the low-voltage input-output device or the high-voltage input-output device is powered, it can supply power to the switching power supply, so that the switching power supply provides voltage to the control device; The control device controls the buck-boost device to work, so that low voltage electricity exists at the low voltage end of the buck-boost device and high voltage electricity exists at the high voltage end of the buck-boost device, the anti-reverse device between the low voltage end of the buck-boost device and the high voltage end of the buck-boost device is disconnected, and the high voltage end of the buck-boost device supplies power to the switching power supply to maintain the current working mode of the buck-boost device; Wherein, the buck-boost device comprises a first capacitor, an inductor, a first drive switch, a second drive switch and a second capacitor; The positive electrode of the first capacitor and the negative electrode of the first capacitor serve as the low voltage end of the buck-boost device; The positive electrode of the second capacitor and the negative electrode of the second capacitor serve as the high voltage end of the buck-boost device; The positive electrode of the first capacitor is connected to the first end of the inductor; The second end of the inductor is connected to the first end of the first drive switch and the second end of the second drive switch respectively; The second end of the first driving switch is connected to the positive electrode of the second capacitor; The first end of the second driving switch is connected to the negative electrode of the first capacitor and the negative electrode of the second capacitor respectively; The third end of the first drive switch and the third end of the second drive switch serve as control ends of the buck-boost device; Wherein, the anti-reverse device includes a first anti-reverse diode and a second anti-reverse diode; The positive electrode of the first capacitor is connected to the positive electrode of the first anti-reverse diode; The cathode of the first anti-reverse diode is connected to the anode port of the input end of the switching power supply; The negative electrode port of the input end of the switching power supply is connected to the positive electrode of the second anti-reverse diode; The cathode of the second anti-reverse diode is connected to the cathode of the first capacitor.

2. The bidirectional DC conversion circuit according to claim 1, characterized in that: The low voltage input and output device comprises a low voltage input and output port and a low voltage side filter; The low voltage input and output port is connected to the low voltage side filter; The low-voltage side filter is connected to the low-voltage end of the buck-boost device.

3. The bidirectional DC conversion circuit according to claim 1, characterized in that: The high-voltage input-output device includes a high-voltage input-output port and a high-voltage side filter; The high voltage input and output port is connected to the high voltage side filter; The high-voltage side filter is connected to the high-voltage end of the buck-boost device.

4. The bidirectional DC conversion circuit according to claim 1, characterized in that: The first drive switch and the second drive switch are both metal-oxide-semiconductor field effect transistors.

5. The bidirectional DC conversion circuit according to any one of claims 1 to 4, characterized in that: The control device includes a control chip and a drive chip; The switching power supply, the control chip, and the driving chip are connected in sequence; The driving chip is connected to the control end of the buck-boost device.

6. A bidirectional DC converter, characterized in that: A bidirectional DC conversion circuit as described in any one of claims 1 to 5 is provided.

7. An electrical device, characterized in that: A bidirectional DC converter as claimed in claim 6 is provided.

8. The electrical equipment according to claim 7, characterized in that: The electrical equipment is an air conditioner.

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