DC converter and circuit breaker

Abstract

The present invention provides a DC converter and a circuit breaker, belonging to the field of power supply technology. The converter includes: a first switch unit, a second switch unit, a third switch unit, a first unidirectional conduction unit, a first inductor, a second inductor, a first capacitor, a second capacitor and a controller; the controller controls the DC converter to work in a boost state, a transition state or a buck state according to the voltage of a DC input signal, so that the DC converter outputs a constant voltage; the DC converter switches between the boost state and the buck state through a transition state; wherein, when the DC converter is in the transition state, there is a current path that is the same as the boost state, and there is also a current path that is the same as the buck state. The present invention provides a new structure of a DC converter, so that a transition state with the same current path as the boost state and the buck state can be introduced, so that the boost state and the buck state can be stably transitioned through the transition state, which can effectively reduce the fluctuation of the output voltage and current during the mode switching process, and improve the performance of the system.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and more particularly to a DC converter and circuit breaker. Background Art

[0002] Circuit breakers can be powered by AC-DC converters. AC-DC converters typically include a rectifier and a DC-DC converter. The rectifier rectifies the alternating current into a waveform, and then the DC-DC converter outputs constant voltage DC power.

[0003] DC-DC converters typically utilize the energy storage characteristics of energy storage elements. Through the operation of a controllable switch, the input electrical energy is stored in the energy storage element and then released to provide energy to the load. When the input voltage is greater than the rated output voltage, the DC-DC converter needs to step down, which is achieved by controlling the controllable switch to operate in step-down mode; when the input voltage is less than the rated output voltage, the DC-DC converter needs to step up, which is achieved by controlling the controllable switch to operate in step-up mode.

[0004] In the existing technology, when DC-DC converters are used in ACDC, since the input of the DC-DC converter is a swivel signal, the DC-DC converter is usually controlled to operate in boost mode and buck mode to achieve constant voltage output. However, hard switching between boost mode and buck mode will cause large ripple in output voltage and current, affecting the performance of DC-DC converter. Summary of the Invention

[0005] This invention provides a DC-DC converter and circuit breaker to solve the problem in the prior art where hard switching of DC-DC converters leads to large output voltage and current ripple, affecting the performance of the DC-DC converter.

[0006] In a first aspect, embodiments of the present invention provide a DC-DC converter, wherein the positive input terminal and the negative input terminal of the DC-DC converter are used to input DC input signals, and the positive output terminal and the negative output terminal of the DC-DC converter are used to supply power to a load; the DC-DC converter module includes: a first switching unit, a second switching unit, a third switching unit, a first unidirectional conduction unit, a first inductor, a second inductor, a first capacitor, a second capacitor, and a controller;

[0007] The first terminal of the first switching unit is connected to the first terminal of the first inductor and the anode of the first unidirectional conducting unit, respectively; the second terminal of the first switching unit is connected to the first terminal of the second inductor, the second terminal of the first capacitor and the second terminal of the third switching unit, respectively.

[0008] The first end of the second switching unit is connected to the cathode of the first unidirectional conducting unit and the first end of the first capacitor, respectively. The second end of the second switching unit is connected to the first end of the third switching unit, the first end of the second capacitor, and the positive output end of the DC-DC converter, respectively.

[0009] The second terminal of the first inductor is connected to the positive input terminal of the DC-DC converter;

[0010] The second terminal of the second inductor is connected to the negative input terminal of the DC-DC converter, the negative output terminal of the DC-DC converter, and the second terminal of the second capacitor, respectively.

[0011] The controller is connected to the control terminals of the first switch unit, the second switch unit, and the third switch unit, respectively.

[0012] The controller is used to control the DC-DC converter to operate in boost, transient, or buck mode according to the voltage of the DC input signal, so that the positive and negative output terminals of the DC-DC converter output a constant voltage according to the rated output voltage; the transition mode is used when switching between boost and buck modes.

[0013] When the DC-DC converter is in the transient state, there is the same current path as in the boost state, and there is also the same current path as in the buck state.

[0014] Optionally, the first switching unit, the second switching unit, and the third switching unit are all formed by switching transistors.

[0015] Optionally, the switching transistor is a MOSFET.

[0016] Optionally, the first unidirectional conduction unit is formed by a diode.

[0017] Optionally, the DC-DC converter can be controlled to operate in boost, transient, or buck mode based on the voltage of the DC input signal, including:

[0018] When the voltage of the DC input signal is less than the first preset voltage, the DC converter is controlled to operate in boost mode;

[0019] When the voltage of the DC input signal is not less than the first preset voltage and not greater than the second preset voltage, the DC converter is controlled to operate in the transient state.

[0020] When the voltage of the DC input signal is greater than the second preset voltage, the DC converter is controlled to operate in buck mode;

[0021] The first preset voltage is less than the rated output voltage, and the rated output voltage is less than the second preset voltage.

[0022] Optionally, controlling the DC-DC converter to operate in boost mode includes:

[0023] The second switch unit is turned on, and the third switch unit is turned off.

[0024] The first duty cycle is determined based on the voltage of the DC input signal, and the first switching unit is controlled to operate according to the first duty cycle.

[0025] Optionally, controlling the DC-DC converter to operate in the transient state includes:

[0026] When the voltage of the DC input signal is not less than the first preset voltage and not greater than the rated output voltage, the first and third switching units are controlled to open, and the second switching unit is controlled to turn on.

[0027] When the voltage of the DC input signal is greater than the rated output voltage but not greater than the second preset voltage, the first and second switching units are controlled to open, and the third switching unit is controlled to open.

[0028] Optionally, controlling the DC-DC converter to operate in buck mode includes:

[0029] Control the first switching unit to turn off;

[0030] The second duty cycle is determined based on the voltage of the DC input signal, the second switching unit is controlled to operate according to the second duty cycle, and the third switching unit is controlled to conduct in a complementary manner with the second switching unit.

[0031] Optionally, the formulas for calculating the first inductance and the second inductance are as follows:

[0032]

[0033]

[0034]

[0035] The formula for calculating the first capacitor is:

[0036]

[0037] in, The inductance of the first inductor. This is the inductance of the second inductor; For the switching cycle, For input resistance, This represents the peak value of the input voltage. The angular velocity of the AC power supply. This is the rated output voltage; Rated power, For input line frequency, This represents the change in DC voltage.

[0038] Secondly, embodiments of the present invention provide a circuit breaker, including any of the DC-DC converters provided in the first aspect above.

[0039] This invention provides a DC-DC converter and a circuit breaker. The positive and negative input terminals of the DC-DC converter are used to input DC input signals, and the positive and negative output terminals of the DC-DC converter are used to supply power to the load. The DC-DC converter module includes: a first switching unit, a second switching unit, a third switching unit, a first unidirectional conducting unit, a first inductor, a second inductor, a first capacitor, a second capacitor, and a controller. The first terminal of the first switching unit is connected to the first terminal of the first inductor and the anode of the first unidirectional conducting unit, respectively. The second terminal of the first switching unit is connected to the first terminal of the second inductor, the second terminal of the first capacitor, and the second terminal of the third switching unit, respectively. The first terminal of the second switching unit is connected to the cathode of the first unidirectional conducting unit and the first terminal of the first capacitor, respectively. The second terminal of the second switching unit is connected to the third switching unit, respectively. The first terminal of the first capacitor, the first terminal of the second capacitor, and the positive output terminal of the DC-DC converter are connected; the second terminal of the first inductor is connected to the positive input terminal of the DC-DC converter; the second terminal of the second inductor is connected to the negative input terminal, the negative output terminal of the DC-DC converter, and the second terminal of the second capacitor; the controller is connected to the control terminals of the first switching unit, the second switching unit, and the third switching unit; the controller is used to control the DC-DC converter to operate in boost mode, transient mode, or buck mode according to the voltage of the DC input signal, so that the positive output terminal and the negative output terminal of the DC-DC converter output a constant voltage according to the rated output voltage; the switching between boost mode and buck mode goes through a transient mode; wherein, when the DC-DC converter is in the transient mode, there is the same current path as in the boost mode and the same current path as in the buck mode. This invention provides a new DC-DC converter topology that can operate in three modes: boost mode, buck mode, or transient mode. The boost mode and transient mode share the same current path, as do the buck mode and transient mode. The boost mode and buck mode do not switch directly but instead switch through the transient mode. This results in smaller output voltage and current ripple, avoiding large ripple caused by hard switching and effectively improving the performance of the DC-DC converter. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a circuit schematic diagram of a DC-DC converter module provided in an embodiment of the present invention;

[0042] Figure 2 This is a waveform diagram of a DC input signal provided in an embodiment of the present invention;

[0043] Figure 3 yes Figure 2 The diagram shown is an equivalent circuit diagram of a DC-DC converter module in boost mode.

[0044] Figure 4 yes Figure 2 The diagram shown is another equivalent circuit diagram of the DC-DC converter module in boost mode.

[0045] Figure 5 yes Figure 2 The diagram shown is an equivalent circuit diagram of a DC-DC converter module in the transient state.

[0046] Figure 6 yes Figure 2 The diagram shows another equivalent circuit of the DC-DC converter module in the transient state.

[0047] Figure 7 yes Figure 2 The diagram shown is an equivalent circuit diagram of a DC-DC converter module in buck mode.

[0048] Figure 8 yes Figure 2 The diagram shown is another equivalent circuit diagram of the DC-DC converter module in buck mode. Detailed Implementation

[0049] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0050] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0051] The implementation of the present invention will be described in detail below with reference to the accompanying drawings:

[0052] Figure 1 This is a schematic diagram of a DC-DC converter provided in an embodiment of the present invention. The positive and negative input terminals of the DC-DC converter are used to input a DC input signal Vdc, and the positive and negative output terminals of the DC-DC converter are used to supply power to the load; see reference... Figure 1The aforementioned DC-DC converter module includes: a first switching unit 11, a second switching unit 12, a third switching unit 13, a first unidirectional conduction unit 14, a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, and a controller.

[0053] The first end of the first switching unit 11 is connected to the first end of the first inductor L1 and the anode of the first unidirectional conduction unit 14, respectively. The second end of the first switching unit 11 is connected to the first end of the second inductor L2, the second end of the first capacitor C1 and the second end of the third switching unit 13, respectively.

[0054] The first end of the second switching unit 12 is connected to the cathode of the first unidirectional conduction unit 14 and the first end of the first capacitor C1, respectively. The second end of the second switching unit 12 is connected to the first end of the third switching unit 13, the first end of the second capacitor C2 and the positive output terminal of the DC converter, respectively.

[0055] The second terminal of the first inductor L1 is connected to the positive input terminal of the DC-DC converter;

[0056] The second terminal of the second inductor L2 is connected to the negative input terminal of the DC-DC converter, the negative output terminal of the DC-DC converter, and the second terminal of the second capacitor C2, respectively.

[0057] The controller is connected to the control terminal of the first switch unit 11, the control terminal of the second switch unit 12, and the control terminal of the third switch unit 13, respectively.

[0058] The controller is used to control the DC-DC converter to operate in boost, transient, or buck mode according to the voltage of the DC input signal, so that the positive and negative output terminals of the DC-DC converter output a constant voltage according to the rated output voltage; the transition mode is used when switching between boost and buck modes.

[0059] When the DC-DC converter is in the transient state, there is the same current path as in the boost state, and there is also the same current path as in the buck state.

[0060] refer to Figure 1This invention provides a novel DC-DC converter topology. Through the switching of the first switching unit 11, the second switching unit 12, and the third switching unit 13, the DC-DC converter exhibits three modes: boost mode, buck mode, and transition mode. The switching between boost and buck modes is not direct but must occur through a transition mode. For example, when switching from boost to buck mode, the boost mode first switches to a transition mode, and then from the transition mode back to buck mode; or when switching from buck to boost mode, the buck mode first switches to a transition mode, and then from the transition mode back to boost mode. Since the boost and transition modes share the same current path, the states of the various devices in the DC-DC converter do not change significantly during mode switching, thus preventing large ripple in the output voltage and current, improving switching smoothness, and enhancing the performance of the DC-DC converter.

[0061] In one possible implementation, refer to Figure 1 The first switching unit 11, the second switching unit 12 and the third switching unit 13 can all be formed by switching transistors (Q1, Q2 and Q3).

[0062] In this embodiment of the invention, each switching unit can be formed by a switching transistor (Q1, Q2 and Q3), and the on and off of each switching unit can be controlled by controlling the on and off of the switching transistor.

[0063] In one possible implementation, refer to Figure 1 The switching transistor can be a MOSFET.

[0064] In one possible implementation, refer to Figure 1 The first unidirectional conduction unit 14 is formed by a diode (D1).

[0065] In one possible implementation, controlling the DC-DC converter to operate in boost, transient, or buck mode based on the voltage of the DC input signal Vdc may include:

[0066] S101: When the voltage of the DC input signal Vdc is less than the first preset voltage Vd1, the DC converter is controlled to operate in boost mode;

[0067] S102: When the voltage of the DC input signal Vdc is not less than the first preset voltage Vd1 and not greater than the second preset voltage Vd2, the DC converter is controlled to operate in the transient state.

[0068] S103: When the voltage of the DC input signal Vdc is greater than the second preset voltage Vd2, control the DC converter to operate in buck mode;

[0069] Among them, the first preset voltage Vd1 is less than the rated output voltage, and the rated output voltage is less than the second preset voltage Vd2.

[0070] For example, in an AC-DC converter, the rectified AC power output is a convex wave, meaning the DC input signal Vdc is a convex wave. (See reference...) Figure 2 The DC input signal Vdc gradually rises and then falls. When the DC input signal Vdc is less than the rated output voltage, it needs to be boosted; conversely, when the DC input signal Vdc is not less than the rated output voltage, it needs to be bucked. Therefore, the DC converter needs to switch between boost and buck states.

[0071] In this embodiment of the invention, reference Figure 2 A first preset voltage Vd1 and a second preset voltage Vd2 are set, where the first preset voltage Vd1 is less than the rated output voltage and the second preset voltage Vd2 is greater than the rated output voltage. From time 0 to t1, the DC input signal Vdc is less than the first preset voltage Vd1, indicating a boost state; as the voltage increases, from t1 to t... a At a certain moment, when the voltage of the DC input signal Vdc is not less than the first preset voltage Vd1, it enters the transition state. There is an identical current loop between the boost state and the transition state, allowing for a smooth transition without large fluctuations in output voltage and current. As the voltage of the DC input signal Vdc continues to rise, t... a ~T p At time / 4, the voltage of the DC input signal Vdc is greater than the second preset voltage Vd2, and the DC converter switches to buck mode. Similarly, since there is the same current loop between the buck mode and the transient mode, the transition can be smooth. Thus, a smooth switching between the boost mode and the buck mode can be achieved through the transient mode, without generating large output voltage and current ripple, thereby improving the performance of the DC converter.

[0072] Similarly, T p / 4~ t b At time t, the DC-DC converter is in buck mode; b At time ~t2, the DC-DC converter switches to transient state; t2~T p At time / 2, the DC-DC converter switches to boost mode. Where T... p This refers to the cycle of the AC power supply.

[0073] In one possible implementation, S101 may include:

[0074] S1011: Control the second switching unit 12 to be turned on, and control the third switching unit 13 to be turned off;

[0075] S1012: Determine the first duty cycle based on the voltage of the DC input signal Vdc, and control the first switching unit 11 to operate according to the first duty cycle.

[0076] In this embodiment of the invention, when the DC-DC converter operates in boost mode, the second switching unit 12 is turned on, the third switching unit 13 is turned off, and PWM control is applied to the first switching unit 11. During the power supply phase, the first switching unit 11 is turned off, forming... Figure 3 The current path shown uses a DC input signal Vdc to charge the first capacitor C1 and the second capacitor C2, thus powering the load. During the freewheeling phase, the first switching unit 11 is turned on, forming... Figure 4 The current path shown has the first capacitor C1 and the second capacitor C2 supplying power to the load, while the DC input signal Vdc supplies power to the first inductor L1 and the second inductor L2. The two inductors are connected in series, resulting in low ripple. In this mode, the input side continues to flow with low ripple.

[0077] The duty cycle of the first switching unit 11 can be determined by the ratio of the DC input signal Vdc to the rated output voltage.

[0078] In one possible implementation, S102 may include:

[0079] S1021: When the voltage of the DC input signal Vdc is not less than the first preset voltage Vd1 and not greater than the rated output voltage, control the first switch unit 11 and the third switch unit 13 to open, and control the second switch unit 12 to turn on.

[0080] S1022: When the voltage of the DC input signal Vdc is greater than the rated output voltage but not greater than the second preset voltage Vd2, the first switch unit 11 and the second switch unit 12 are controlled to open, and the third switch unit 13 is controlled to turn on.

[0081] When the DC-DC converter operates in transient mode, and the voltage of the DC input signal Vdc is not less than the first preset voltage Vd1 and not greater than the rated output voltage, the reference voltage is... Figure 2 t1~t x At any given moment, a voltage boost is still required. At this time, the first switching unit 11 and the third switching unit 13 are disconnected, and the second switching unit 12 is turned on, forming... Figure 5 The current path shown is consistent with the current path in the boost state power supply stage. The circuit boosts the voltage, and the device state changes little, so it can smoothly transition from the boost state to the transition state.

[0082] When the voltage of the DC input signal Vdc is greater than the rated output voltage but not greater than the second preset voltage Vd2, t x ~t a At a certain time, the first switch unit 11 and the second switch unit 12 are disconnected, and the third switch unit 13 is turned on, forming... Figure 6 The current path shown is powered by the second capacitor C2, freewheeled by the second inductor L2, with a step-down output on the output side, and the DC input signal Vdc charges the first capacitor C1.

[0083] In one possible implementation, S103 may include:

[0084] S1031: Control the first switching unit 11 to turn off;

[0085] S1032: Determine the second duty cycle based on the voltage of the DC input signal Vdc, control the second switching unit 12 to operate according to the second duty cycle, and control the third switching unit 13 to be complementary to the second switching unit 12 for conduction.

[0086] When the DC-DC converter operates in buck mode, the first switching unit 11 is turned off, and the third switching unit 13 is complementary to the second switching unit 12 in conducting mode; when the second switching unit 12 is turned off and the third switching unit 13 is turned on, a voltage regulation is formed. Figure 7 The current path shown is the same as the step-down phase of the transient state, enabling a smooth switching from the transient state to the step-down state. When the second switching unit 12 is turned on and the third switching unit 13 is turned off, a current path is formed. Figure 8 The current path shown allows the DC input signal Vdc and the first capacitor C1 to simultaneously power the load.

[0087] In one possible implementation, the formulas for calculating the first inductance L1 and the second inductance L2 can be:

[0088]

[0089]

[0090]

[0091] The formula for calculating the first capacitor C1 is as follows:

[0092] ;

[0093] in, The inductance of the first inductor. This is the inductance of the second inductor; For the switching cycle, For input resistance, This represents the peak value of the input voltage. The angular velocity of the AC power supply. This is the rated output voltage; Rated power, For input line frequency, This represents the change in DC voltage.

[0094] The selection of parameters for the first inductor L1, the second inductor L2, and the first capacitor C1 also affects the current ripple. Therefore, it is necessary to select appropriate parameters for the first inductor L1, the second inductor L2, and the first capacitor C1 to reduce the current ripple. Specifically, based on the peak inductor current ripple in boost and buck modes, the calculation formulas for the first inductor L1 and the second inductor L2 are derived as shown above, resulting in a smaller current ripple in the DC-DC converter. Simultaneously, in buck mode, the first inductor L1 and the first capacitor C1 form a low-pass input filter. To ensure that changes in input voltage do not affect the output voltage and input current, the calculation formula for the first capacitor C1 is derived, further reducing the output voltage and current ripple and improving the performance of the DC-DC converter.

[0095] Corresponding to the above embodiments, this invention also provides a circuit breaker, including the DC converter provided in any of the above embodiments, and has the advantages of the above embodiments, which will not be elaborated here.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate 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 used to input a DC input signal, and the positive output terminal and the negative output terminal of the DC converter are used to supply power to the load; the DC conversion module includes: a first switch unit, a second switch unit, a third switch unit, a first unidirectional conduction unit, a first inductor, a second inductor, a first capacitor, a second capacitor and a controller; The first end of the first switch unit is respectively connected to the first end of the first inductor and the anode of the first unidirectional conductive unit, and the second end of the first switch unit is respectively connected to the first end of the second inductor, the second end of the first capacitor and the second end of the third switch unit; The first end of the second switch unit is respectively connected to the cathode of the first unidirectional conductive unit and the first end of the first capacitor, and the second end of the second switch unit is respectively connected to the first end of the third switch unit, the first end of the second capacitor and the positive output end of the DC converter; The second end of the first inductor is connected to the positive input end of the DC converter; The second end of the second inductor is respectively connected to the negative input end of the DC converter, the negative output end of the DC converter and the second end of the second capacitor; The controller is respectively connected to the control end of the first switch unit, the control end of the second switch unit and the control end of the third switch unit; The controller is used to control the DC converter to operate in a boost state, a transition state or a buck state according to the voltage of the DC input signal, so that the DC converter outputs a constant voltage according to the rated output voltage between the positive output terminal and the negative output terminal; the transition state is passed when switching between the boost state and the buck state; When the DC converter is in a transition state, there is a current path that is the same as that in a boost state, and there is also a current path that is the same as that in a buck state.

2. The DC converter according to claim 1, characterized in that: The first switch unit, the second switch unit and the third switch unit are all formed by switch tubes.

3. The DC converter according to claim 2, characterized in that: The switch tube is a MOS tube.

4. The DC converter according to claim 1, characterized in that: The first unidirectional conductive unit is formed by a diode.

5. The DC converter according to any one of claims 1 to 4, characterized in that: The step of controlling the DC converter to operate in a boost state, a transition state or a buck state according to the voltage of the DC input signal includes: When the voltage of the DC input signal is less than a first preset voltage, controlling the DC converter to operate in a boost state; When the voltage of the DC input signal is not less than the first preset voltage and not greater than the second preset voltage, controlling the DC converter to operate in a transition state; When the voltage of the DC input signal is greater than the second preset voltage, controlling the DC converter to operate in a step-down state; The first preset voltage is lower than the rated output voltage, and the rated output voltage is lower than the second preset voltage.

6. The DC converter according to claim 5, characterized in that: The controlling the DC converter to operate in a boost state comprises: Controlling the second switch unit to be turned on, and controlling the third switch unit to be turned off; A first duty cycle is determined according to the voltage of the DC input signal, and the first switch unit is controlled to operate according to the first duty cycle.

7. The DC converter according to claim 6, characterized in that: The controlling the DC converter to operate in a transition state comprises: When the voltage of the DC input signal is not less than the first preset voltage and not greater than the rated output voltage, the first switch unit and the third switch unit are controlled to be disconnected, and the second switch unit is controlled to be turned on; When the voltage of the DC input signal is greater than the rated output voltage and not greater than the second preset voltage, the first switch unit and the second switch unit are controlled to be disconnected, and the third switch unit is controlled to be turned on.

8. The DC converter according to claim 7, characterized in that: The step of controlling the DC converter to operate in a step-down state includes: Controlling the first switch unit to turn off; A second duty cycle is determined according to the voltage of the DC input signal, the second switch unit is controlled to operate according to the second duty cycle, and the third switch unit is controlled to be complementary to the second switch unit.

9. The DC converter according to claim 8, characterized in that: The calculation formulas of the first inductance and the second inductance are: The calculation formula of the first capacitance is: in, is the inductance of the first inductor, is the inductance of the second inductor; is the switching cycle, is the input resistance, is the input voltage peak value, is the angular velocity of the AC power supply, is the rated output voltage; is the rated power, is the input line frequency, is the DC voltage change.

10. A circuit breaker, characterized in that: Comprising a DC converter as claimed in any one of claims 1 to 9.

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