DC converters, power supplies and circuit breakers

Abstract

The present invention provides a direct current converter, a power supply and a circuit breaker, belonging to the technical field of power supply. The positive input terminal and the negative input terminal of the direct current converter are respectively used to connect with the positive and negative electrodes of the direct current power supply, and the positive output terminal and the negative output terminal of the direct current converter are used to supply power to the load; the direct current converter includes: a coupled inductor, a switch unit, a first unidirectional conduction unit, a second unidirectional conduction unit, a third unidirectional conduction unit, a fourth unidirectional conduction unit, a fifth unidirectional conduction unit, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor and a controller; the present invention provides a direct current converter topology, which uses a coupled inductor to achieve high voltage gain output, can achieve high gain output without a high duty cycle, and has a simple topology structure, a small number of components and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to a direct current converter, a power supply and a circuit breaker. Background Art

[0002] A DC converter is a device that converts one DC power source into another DC power source with different output characteristics and is widely used in power supply equipment.

[0003] In the prior art, a conventional DC converter is usually formed of a buck architecture, a boost architecture, or a buck-boost hybrid architecture by semiconductor switching elements, etc. The voltage change is achieved by the action of the semiconductor switching elements, and the gain of the DC converter is adjusted by adjusting the duty cycle of the semiconductor switching elements.

[0004] Since the extremely large duty cycle of the semiconductor switching element will affect the dynamic performance and reliability of the DC converter, the duty cycle adjustment range of the semiconductor switching element is limited, and its gain range is also limited, which cannot meet the application requirements of high gain. Summary of the invention

[0005] The embodiments of the present invention provide a DC converter, a power supply and a circuit breaker to solve the problem that the DC converter in the prior art has limited gain and cannot meet the requirements of high-gain applications.

[0006] In a first aspect, an embodiment of the present invention provides a DC converter, wherein a positive input terminal and a negative input terminal of the DC converter are respectively used to be connected to a positive and negative electrode of a DC power supply, and a positive output terminal and a negative output terminal of the DC converter are used to supply power to a load; the DC converter comprises: a coupled inductor, a switch unit, a first unidirectional conduction unit, a second unidirectional conduction unit, a third unidirectional conduction unit, a fourth unidirectional conduction unit, a fifth unidirectional conduction unit, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor and a controller;

[0007] The same-name ends of the primary winding of the coupling inductor are respectively connected to the positive input end of the DC converter and the first end of the first capacitor, and the opposite-name ends of the primary winding of the coupling inductor are respectively connected to the first end of the second capacitor, the anode of the first unidirectional conductive unit, and the first end of the switch unit; the same-name ends of the secondary winding of the coupling inductor are respectively connected to the cathode of the second unidirectional conductive unit and the second end of the second capacitor, and the opposite-name ends of the secondary winding of the coupling inductor are respectively connected to the first end of the fourth capacitor and the anode of the third unidirectional conductive unit;

[0008] The second end of the switch unit is respectively connected to the first end, the negative input end, the second end and the negative output end of the third capacitor, and the control end of the switch unit is connected to the controller;

[0009] The anode of the fourth unidirectional conductive unit is respectively connected to the second end of the first capacitor and the cathode of the third unidirectional conductive unit, and the cathode of the fourth unidirectional conductive unit is respectively connected to the second end of the fourth capacitor and the anode of the fifth unidirectional conductive unit;

[0010] The cathode of the fifth unidirectional conductive unit is respectively connected to the first end and the positive output end of the fifth capacitor;

[0011] The second end of the third capacitor is respectively connected to the cathode of the first unidirectional conductive unit and the anode of the second unidirectional conductive unit;

[0012] The controller is used to control the switch unit to conduct according to a preset duty cycle.

[0013] Optionally, the calculation formula for the preset duty cycle is:

[0014]

[0015]

[0016] in, is the preset duty cycle, is the gain of the DC converter, is the number of turns of the primary winding of the coupled inductor, is the number of turns of the secondary winding of the coupled inductor.

[0017] Optionally, the coupled inductor has an interlaced winding structure.

[0018] Optionally, the switch unit is composed of a switch tube.

[0019] Optionally, the switch tube is a MOS tube.

[0020] Optionally, the switch tube is an NMOS tube.

[0021] Optionally, the first unidirectional conducting unit, the second unidirectional conducting unit, the third unidirectional conducting unit, the fourth unidirectional conducting unit and the fifth unidirectional conducting unit are all composed of diodes.

[0022] Optionally, the first capacitor, the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor are all polarized capacitors.

[0023] In a second aspect, an embodiment of the present invention provides a power supply, comprising the DC converter provided in the first aspect of the above embodiment.

[0024] In a third aspect, an embodiment of the present invention provides a circuit breaker, comprising the power supply and the circuit breaker body provided in the second aspect of the above embodiment;

[0025] The power supply supplies power to the circuit breaker body.

[0026] The embodiment of the present invention provides a DC converter, a power supply and a circuit breaker. The positive input terminal and the negative input terminal of the DC converter are respectively used to connect to the positive and negative electrodes of the DC power supply, and the positive output terminal and the negative output terminal of the DC converter are used to supply power to the load; the DC converter includes: a coupled inductor, a switch unit, a first unidirectional conduction unit, a second unidirectional conduction unit, a third unidirectional conduction unit, a fourth unidirectional conduction unit, a fifth unidirectional conduction unit, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor and a controller; the same-name ends of the primary winding of the coupled inductor are respectively connected to the positive input terminal of the DC converter and the first end of the first capacitor, and the opposite-name ends of the primary winding of the coupled inductor are respectively connected to the first end of the second capacitor, the anode of the first unidirectional conduction unit and the first end of the switch unit; the same-name ends of the secondary winding of the coupled inductor are respectively connected to the cathode of the second unidirectional conduction unit and the cathode of the second capacitor. The second end of the capacitor is connected, and the opposite end of the secondary winding of the coupled inductor is respectively connected to the first end of the fourth capacitor and the anode of the third unidirectional conduction unit; the second end of the switch unit is respectively connected to the first end, the negative input end, the second end and the negative output end of the fifth capacitor, and the control end of the switch unit is connected to the controller; the anode of the fourth unidirectional conduction unit is respectively connected to the second end of the first capacitor and the cathode of the third unidirectional conduction unit, and the cathode of the fourth unidirectional conduction unit is respectively connected to the second end of the fourth capacitor and the anode of the fifth unidirectional conduction unit; the cathode of the fifth unidirectional conduction unit is respectively connected to the first end and the positive output end of the fifth capacitor; the second end of the third capacitor is respectively connected to the cathode of the first unidirectional conduction unit and the anode of the second unidirectional conduction unit; the controller is used to control the switch unit to conduct according to the preset duty cycle. In the embodiment of the present invention, the hybrid scheme of the coupled inductor, the unidirectional conduction unit and the capacitor realizes high-gain output through the difference in the turns ratio between the coupled inductors, and the switch unit can realize high-gain output without high duty cycle driving, which can meet the actual application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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 labor.

[0028] Figure 1 1 is a schematic diagram of a circuit structure of a DC converter provided by an embodiment of the present invention;

[0029] Figure 2 yes Figure 1 An equivalent circuit diagram of the DC converter shown;

[0030] Figure 3 yes Figure 1Another equivalent circuit diagram of the DC converter shown;

[0031] Figure 4 yes Figure 1 Waveform diagram of each device in the DC converter shown in the working state;

[0032] Figure 5 yes Figure 1 The voltage gain curve comparison diagram of the DC converter at different turns ratios is shown;

[0033] Figure 6 is a schematic diagram of leakage inductance of a DC converter provided by an embodiment of the present invention;

[0034] Figure 7 yes Figure 1 The voltage gain curve comparison diagram of the DC converter under different coupling coefficients is shown. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the present solution, the technical solution in the embodiments of the present solution will be clearly described below in conjunction with the drawings in the embodiments of the present solution. Obviously, the described embodiments are embodiments of a part of the present solution, not all embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.

[0036] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and is intended to cover non-exclusive inclusions and is not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0037] The following is a detailed description of the implementation of the present invention in conjunction with the specific drawings:

[0038] Figure 1 A schematic diagram of the structure of a DC converter provided in an embodiment of the present invention. The positive input terminal and the negative input terminal of the DC converter are respectively used to connect to the positive and negative electrodes of the DC power supply Vin, and the positive output terminal and the negative output terminal of the DC converter are used to supply power to the load;

[0039] Reference Figure 1 The DC converter includes: a coupled inductor Lm, a switch unit 11, a first unidirectional conduction unit 12, a second unidirectional conduction unit 13, a third unidirectional conduction unit 14, a fourth unidirectional conduction unit 15, a fifth unidirectional conduction unit 16, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a controller;

[0040] The same-name ends of the primary winding of the coupling inductor Lm are respectively connected to the positive input end of the DC converter and the first end of the first capacitor C1, and the opposite-name ends of the primary winding of the coupling inductor Lm are respectively connected to the first end of the second capacitor C2, the anode of the first unidirectional conduction unit 12, and the first end of the switch unit 11; the same-name ends of the secondary winding of the coupling inductor Lm are respectively connected to the cathode of the second unidirectional conduction unit 13 and the second end of the second capacitor C2, and the opposite-name ends of the secondary winding of the coupling inductor Lm are respectively connected to the first end of the fourth capacitor C4 and the anode of the third unidirectional conduction unit 14;

[0041] The second end of the switch unit 11 is respectively connected to the first end, the negative input end, the second end and the negative output end of the third capacitor C3, and the fifth capacitor C5, and the control end of the switch unit 11 is connected to the controller;

[0042] The anode of the fourth unidirectional conductive unit 15 is respectively connected to the second end of the first capacitor C1 and the cathode of the third unidirectional conductive unit 14, and the cathode of the fourth unidirectional conductive unit 15 is respectively connected to the second end of the fourth capacitor C4 and the anode of the fifth unidirectional conductive unit 16;

[0043] The cathode of the fifth unidirectional conducting unit 16 is respectively connected to the first end and the positive output end of the fifth capacitor C5;

[0044] The second end of the third capacitor C3 is connected to the cathode of the first unidirectional conductive unit 12 and the anode of the second unidirectional conductive unit 13 respectively;

[0045] The controller is used to control the switch unit 11 to be turned on according to a preset duty cycle.

[0046] The embodiment of the present invention provides a new topology structure of a DC converter, which utilizes the mutual induction of two coils of a coupled inductor Lm to achieve high-gain output.

[0047] Specifically, it is assumed that each unidirectional conductive unit is formed by a diode, and the switch unit 11 is a switch tube. Figure 1 , when the switch unit 11 is turned on, Figure 2 As shown in the equivalent circuit diagram, the DC power supply Vin charges the primary winding of the coupled inductor Lm through the switch unit 11, and the current flowing through the primary winding of the coupled inductor Lm gradually increases. Figure 4 ( V gs is the driving signal of the switch tube, i Lm is the current flowing through the primary side of the coupled inductor Lm, i D1 , i D2 , i D3 , i D4 ,i D5 are the currents flowing through the first unidirectional conductive unit 12, the second unidirectional conductive unit 13, the third unidirectional conductive unit 14, the fourth unidirectional conductive unit 15 and the fifth unidirectional conductive unit 16 respectively; T s and D are the switching period and duty cycle of the switch tube respectively). At this time, the secondary winding of the coupled inductor Lm generates an induced current (the direction of the current is as follows Figure 2 As shown). Affected by the voltage across the third capacitor C3, the first unidirectional conduction unit 12 is reverse biased and disconnected; the voltage on the second capacitor C2 is small, and the second unidirectional conduction unit 13 is forward-conducted; affected by the secondary induced electromotive force of the coupled inductor Lm, the fourth unidirectional conduction unit 15 is turned on, the third unidirectional conduction unit 14 and the fifth unidirectional conduction unit 16 are reverse biased and disconnected, and the DC power supply Vin charges the fourth capacitor C4 through the first capacitor C1, the fourth unidirectional conduction unit 15, and the secondary winding of the coupled inductor Lm, and the fifth capacitor C5 is discharged to supply energy to the load. Among them, the waveform diagrams of each device refer to Figure 4 .

[0048] When the switch unit 11 is turned off, Figure 3 As shown in the equivalent circuit diagram, the first unidirectional conduction unit 12 is turned on, the coupled inductor Lm releases energy, the DC power supply Vin charges the third capacitor C3 through the primary side of the coupled inductor Lm, and the current flowing through the primary side of the coupled inductor Lm gradually decreases. Figure 4 At this time, the secondary winding of the coupled inductor Lm generates a reverse induced current (the current direction is as follows Figure 3 As shown). Affected by the second capacitor C2, the second unidirectional conduction unit 13 is reverse biased and disconnected; affected by the secondary induced electromotive force of the fourth capacitor C4 and the coupled inductor Lm, the fourth unidirectional conduction unit 15 is reverse biased and disconnected, the third unidirectional conduction unit 14 and the fifth unidirectional conduction unit 16 are turned on, and the DC power supply Vin, the second capacitor C2, the fourth capacitor C4, the primary winding of the coupled inductor Lm and the secondary winding of the coupled inductor Lm jointly supply energy to the load.

[0049] In the embodiment of the present invention, when the switch unit 11 is turned on, the coupled inductor Lm stores energy; when the switch unit 11 is turned off, the coupled inductor Lm releases energy and charges the fifth capacitor C5 together with the DC power supply Vin to achieve voltage boost. The process of switching the switch unit 11 on and off is repeated continuously to achieve stable output of high voltage. Figure 5 The voltage gain curve comparison diagram under different turns ratios n and different duty cycles is shown. Figure 5It can be seen that the gain of the DC converter is not only related to the duty cycle, but also to the turns ratio n of the coupling inductor Lm (the turns ratio of the secondary winding to the primary winding). The larger the duty cycle, the greater the voltage gain, and the larger the turns ratio n, the greater the voltage gain. The topology structure in the embodiment of the present invention can obtain a higher voltage gain at a lower duty cycle, thereby achieving a higher voltage gain.

[0050] At the same time, due to the inevitable leakage inductance of the coupled inductor Lm, for example, refer to Figure 6 , leakage inductance is Lk. Figure 6 When the switch unit 11 is turned on, the leakage inductance Lk stores energy; when the switch unit 11 is turned off, the third unidirectional conduction unit 14 and the first capacitor C1 form a clamping circuit to recover the energy of the leakage inductance Lk, which can effectively reduce the stress of the switch unit 11 (switch tube) and improve the reliability and stability of the DC converter.

[0051] Furthermore, the input and output of the DC converter in the embodiment of the present invention are grounded together, which can effectively reduce the common mode leakage current.

[0052] In one possible implementation, reference Figure 1 , the switch unit 11 can be composed of a switch tube (Q1).

[0053] In the embodiment of the present invention, a switch tube can be used to form the switch unit 11, which has simple control, low device cost and small size.

[0054] In one possible implementation, reference Figure 1 , the switch tube can be a MOS tube.

[0055] In one possible implementation, reference Figure 1 , the switch tube can be an NMOS tube.

[0056] The NMOS switch has a relatively fast conduction speed and can realize high-frequency circuit operation. Therefore, the NMOS switch is used as the switch in the embodiment of the present invention.

[0057] In one possible implementation, reference Figure 1 The first unidirectional conducting unit 12 , the second unidirectional conducting unit 13 , the third unidirectional conducting unit 14 , the fourth unidirectional conducting unit 15 and the fifth unidirectional conducting unit 16 are all composed of diodes ( D1 , D2 , D3 , D4 and D5 ).

[0058] Each unidirectional conducting unit can be a diode, and the device is simple and low in cost.

[0059] In one possible implementation, reference Figure 1 The first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4 and the fifth capacitor C5 are all polar capacitors.

[0060] In a possible implementation manner, the calculation formula for the preset duty cycle may be:

[0061]

[0062]

[0063] in, is the preset duty cycle, is the gain of the DC converter, is the number of turns of the primary winding of the coupled inductor Lm, is the number of turns of the secondary winding of the coupled inductor Lm.

[0064] Depend on Figure 2 and Figure 3 It can be seen that the switch unit 11 operates according to a preset duty cycle. If the turns ratio of the coupled inductor Lm is fixed, the voltage gain can be adjusted by adjusting the duty cycle of the switch unit 11. Similarly, when the duty cycle of the switch unit 11 is fixed, the voltage gain can also be adjusted by adjusting the turns ratio of the coupled inductor Lm. The details will not be repeated here.

[0065] In a possible implementation manner, the coupled inductor Lm may be a staggered winding structure.

[0066] Since the coupled inductor Lm inevitably has leakage inductance, the coupling coefficient of the coupled inductor Lm is The formula is:

[0067]

[0068] in, is the inductance of the coupled inductor Lm, is the inductance of the leakage inductance.

[0069] Figure 7 The voltage gain comparison diagram under different coupling coefficients is shown. Figure 7 It can be seen that the larger the leakage inductance is, the smaller the coupling coefficient is, and the lower the voltage gain of the DC converter is, especially when the duty cycle of the switch unit 11 is high, this phenomenon is more obvious. Therefore, in the embodiment of the present invention, the coupling inductor Lm can adopt an interleaved winding structure to reduce the leakage inductance, proximity effect and skin effect of the coupling inductor Lm, thereby obtaining a higher boost factor, and at the same time, can effectively reduce the electromagnetic interference of the DC converter.

[0070] Corresponding to the above embodiments, an embodiment of the present invention provides a power supply, including the DC converter provided by any of the above embodiments, and having the advantages of the above DC converter, which will not be described in detail here.

[0071] Corresponding to the above embodiments, an embodiment of the present invention provides a circuit breaker, comprising a power supply and a circuit breaker body provided in any of the above embodiments;

[0072] The power supply supplies power to the circuit breaker body; the circuit breaker has the advantages of the above power supply, and the details will not be repeated here.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A DC converter, characterized in that: The positive input terminal and the negative input terminal of the DC converter are respectively used to connect to the positive and negative electrodes of the DC power supply, and the positive output terminal and the negative output terminal of the DC converter are used to supply power to the load; the DC converter comprises: a coupled inductor, a switch unit, a first unidirectional conduction unit, a second unidirectional conduction unit, a third unidirectional conduction unit, a fourth unidirectional conduction unit, a fifth unidirectional conduction unit, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor and a controller; The same-name ends of the primary winding of the coupling inductor are respectively connected to the positive input end of the DC converter and the first end of the first capacitor, and the opposite-name ends of the primary winding of the coupling inductor are respectively connected to the first end of the second capacitor, the anode of the first unidirectional conductive unit, and the first end of the switch unit; the same-name ends of the secondary winding of the coupling inductor are respectively connected to the cathode of the second unidirectional conductive unit and the second end of the second capacitor, and the opposite-name ends of the secondary winding of the coupling inductor are respectively connected to the first end of the fourth capacitor and the anode of the third unidirectional conductive unit; The second end of the switch unit is respectively connected to the first end of the third capacitor, the negative input end, the second end of the fifth capacitor and the negative output end, and the control end of the switch unit is connected to the controller; The anode of the fourth unidirectional conductive unit is respectively connected to the second end of the first capacitor and the cathode of the third unidirectional conductive unit, and the cathode of the fourth unidirectional conductive unit is respectively connected to the second end of the fourth capacitor and the anode of the fifth unidirectional conductive unit; The cathode of the fifth unidirectional conductive unit is respectively connected to the first end of the fifth capacitor and the positive output end; The second end of the third capacitor is respectively connected to the cathode of the first unidirectional conductive unit and the anode of the second unidirectional conductive unit; The controller is used to control the switch unit to be turned on according to a preset duty cycle.

2. The DC converter according to claim 1, characterized in that: The calculation formula of the preset duty cycle is: in, is the preset duty cycle, is the gain of the DC converter, is the number of turns of the primary winding of the coupled inductor, is the number of turns of the secondary winding of the coupled inductor.

3. The DC converter according to claim 1, characterized in that: The coupled inductor has an interlaced winding structure.

4. The DC converter according to any one of claims 1 to 3, characterized in that: The switch unit is composed of a switch tube.

5. The DC converter according to claim 4, characterized in that: The switch tube is a MOS tube.

6. The DC converter according to claim 5, characterized in that: The switch tube is an NMOS tube.

7. The DC converter according to any one of claims 1 to 3, characterized in that: The first one-way conducting unit, the second one-way conducting unit, the third one-way conducting unit, the fourth one-way conducting unit and the fifth one-way conducting unit are all composed of diodes.

8. The DC converter according to any one of claims 1 to 3, characterized in that: The first capacitor, the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor are all polarized capacitors.

9. A power supply, characterized in that: Comprising a DC converter as claimed in any one of claims 1 to 8.

10. A circuit breaker, characterized in that: comprising a power supply and a circuit breaker body as claimed in claim 9; The power supply supplies power to the circuit breaker body.

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