A potential superimposable wide-range high-gain direct current converter

Abstract

This invention discloses a wide-range, high-gain DC-DC converter with superimposed potentials, belonging to the field of DC-DC voltage conversion circuits, including a DC input power supply. E First Inductor L 1. First switching transistor T1, first capacitor C 1. Second inductor L 2. Diode D1, first output capacitor C 1o Third inductor L 3. Second switch T2, third switch T3, fourth switch T4, and second output capacitor C 2o This DC-DC converter features both single-potential and superimposed-potential operation modes, and both modes offer boost and buck conversion capabilities. In single-potential operation mode, the first output capacitor... C 1o The output voltage is supported by the potential at both ends. U o In the superposition of potentials operating mode, the first output capacitor... C 1o Potential at both ends and second output capacitor C 2o The sum of the potentials at both ends supports the output voltage. U o This invention features higher voltage gain, and its output voltage is continuously adjustable over a wide range of 0 to 20 times the input voltage.

Description

Technical Field

[0001] This invention relates to the field of DC voltage conversion circuit technology, and in particular to a wide-range high-gain DC converter with superimposed potential. Background Technology

[0002] In recent years, new energy power generation such as photovoltaic and wind power has shown a rapid development trend. However, new energy power generation is greatly affected by natural environmental factors, and its output power is random and fluctuating. For example, in photovoltaic power generation systems, due to the low output voltage of photovoltaics, traditional boost converter circuits are difficult to meet the voltage conversion requirements of a wide range and high gain.

[0003] While existing DC-DC voltage conversion circuits offer boost functionality, they suffer from low voltage gain and an inability to buck output, failing to meet the demands of applications requiring a wide input voltage range and high output voltage gain. Examples include Chinese invention patents with publication numbers CN106685218 and CN110739851. Chinese invention patent CN106685218 utilizes a single switching transistor to control inductor current and capacitor voltage, providing an output voltage with a certain proportional gain. While this circuit boasts a simple structure, it cannot achieve buck output. Chinese invention patent CN110739851 integrates two boost circuits to create a high-gain circuit; however, its voltage gain is only the sum of the voltage gains of the two boost circuits, limiting its ability to output high-gain voltage, and it also lacks buck output capability.

[0004] Therefore, it is necessary to provide a wide-range, high-gain DC-DC voltage conversion circuit to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a wide-range high-gain DC-DC converter with superimposed potential. By controlling and superimposing the potential of the output capacitor, the DC-DC converter can simultaneously have the ability to boost and buck voltage. It can realize the output voltage is continuously adjustable in a wide range of 0 to 20 times the input voltage, and can meet the application scenarios such as photovoltaic power generation system, energy storage system, and electric vehicle charging with a high gain voltage capability of 20 times.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A wide-range, high-gain DC-DC converter with superimposed potentials, the DC-DC converter comprising a DC input power supply E, a first inductor L1, a first switching transistor T1, a first capacitor C1, a second inductor L2, a diode D1, and a first output capacitor C 1oThe third inductor L3, the second switch T2, the third switch T3, the fourth switch T4, and the second output capacitor C 2o With the cooperation of the first switch T1, the second switch T2, the third switch T3, and the fourth switch T4, the DC-DC converter has a single-potential operating mode and a potential superposition operating mode, and both operating modes have boost and buck functions; in the single-potential operating mode, the first output capacitor C... 1o The output voltage U is supported by the potential at both ends. o In the potential superposition operation mode, the first output capacitor C 1o The potential at both ends and the second output capacitor C 2o The sum of the potentials at both ends supports the output voltage U o .

[0008] A further improvement of the technical solution of the present invention is that the connection method of each component in the DC-DC converter is as follows: the positive terminal of the DC input power supply E is connected to one end of the first inductor L1; the other end of the first inductor L1 is connected to the collector of the first switching transistor T1 and one end of the first capacitor C1; the other end of the first capacitor C1 is connected to the anode of the diode D1 and one end of the second inductor L2; the cathode of the diode D1 is connected to the first output capacitor C 1o One end, the second output capacitor C 2o One end of the third inductor L3 is connected to the collector of the fourth switch T4 and one end of the third inductor L3; the other end of the third inductor L3 is connected to the collectors of the second switch T2 and the third switch T3; the second output capacitor C 2o The other end is connected to the emitter of the fourth switch T4, the emitter of the third switch T3, and the output voltage U. o The positive terminal of the DC input power supply E is connected to the emitter of the first switching transistor T1, the other end of the second inductor L2, and the first output capacitor C. 1o The other end, the emitter of the second switch T2, and the output voltage U o The negative extremes are connected.

[0009] A further improvement to the technical solution of this invention is that the single-potential operation mode is characterized by: the first switch T1 operating at high frequency, the second switch T2 and the third switch T3 both remaining off, and the fourth switch T4 remaining on; the first output capacitor C 1o An electric potential is established at both ends, and the second output capacitor C 2o When the potential at both ends is zero, the output voltage U o The value is equal to the first output capacitor C. 1o Potential at both ends.

[0010] A further improvement of the technical solution of this invention lies in that: in the single potential operation mode, there are the following two operating modes:

[0011] Operating mode I is as follows: the first switch T1 is turned on, the DC input power supply E charges the first inductor L1 through the first switch T1, the first capacitor C1 charges the second inductor L2 through the first switch T1, and the first output capacitor C... 1o Power is supplied to the load via the fourth switching transistor T4;

[0012] Operating mode II is as follows: the first switch T1 is turned off, the DC input power supply E and the first inductor L1 charge the first capacitor C1 in series, and charge the first output capacitor C through diode D1. 1o Charging is achieved by supplying power to the load via the fourth switch T4; the second inductor L2 supplies power to the first output capacitor C via diode D1. 1o It charges and then supplies power to the load through the fourth switch T4.

[0013] A further improvement of the technical solution of the present invention is that, in the single potential operation mode, the voltage gain can be continuously varied within the range of 0 to 4 by adjusting the value of the duty cycle d1.

[0014] A further improvement to the technical solution of this invention lies in the following: the potential superposition operation mode is characterized by: both the first switch T1 and the second switch T2 operating at high frequency, the third switch T3 remaining on, and the fourth switch T4 remaining off, with the first output capacitor C... 1o and the second output capacitor C 2o Both ends have potentials established, and the output voltage U o The value is equal to the first output capacitor C. 1o The potential at both ends and the second output capacitor C 2o The sum of the potentials at both ends.

[0015] A further improvement to the technical solution of this invention lies in the following four operating modes under the potential superposition operation mode:

[0016] Operating mode I is as follows: First switch T1 and second switch T2 are turned on. The DC input power supply E charges the first inductor L1 through the first switch T1, and the first capacitor C1 charges the second inductor L2 through the first switch T1. The first output capacitor C... 1o The third inductor L3 is charged through the second switch T2; the first output capacitor C 1o Second output capacitor C 2o The superimposed potentials supply power to the load;

[0017] Operating mode II is as follows: First switch T1 and third switch T3 are turned on, second switch T2 is turned off, DC input power supply E charges first inductor L1 through first switch T1, and first capacitor C1 charges second inductor L2 through first switch T1; first output capacitor C... 1o The third inductor L3, connected in series with the third inductor L3, supplies power to the load through the third switch T3; the third inductor L3 supplies power to the second output capacitor C through the third switch T3. 2o Charge;

[0018] Operating mode III is as follows: the first switch T1 and the third switch T3 are turned off, the second switch T2 is turned on, the DC input power supply E and the first inductor L1 are connected in series to charge the first capacitor C1, and then charge the first output capacitor C through diode D1. 1o Charging is achieved by charging the third inductor L3 through the second switch T2; DC input power supply E, first inductor L1, and second output capacitor C 2o The load is powered in series with diode D1; the second inductor L2 supplies power to the first output capacitor C through diode D1. 1o While charging, the second output capacitor C 2o The load is powered after being connected in series;

[0019] Operating mode IV is as follows: the first switch T1 and the second switch T2 are off, the third switch T3 is on, the DC input power supply E and the first inductor L1 are connected in series to charge the first capacitor C1, and charge the first output capacitor C through diode D1. 1o Charging; the DC input power supply E, the first inductor L1, and the third inductor L3 are connected in series and then supply power to the load through diode D1 and the third switch T3; the third inductor L3 supplies power to the second output capacitor C through the third switch T3. 2o Charging; the second inductor L2 supplies power to the first output capacitor C through diode D1. 1o The circuit is charged, and then connected in series with the third inductor L3 to supply power to the load through the third switch T3.

[0020] A further improvement of the technical solution of the present invention is that, when the voltage gain is greater than 4, the DC converter operates in the potential superposition mode. When the duty cycle d1 of the first switch T1 and the duty cycle d2 of the second switch T2 are both 0.8, the voltage gain of the DC converter reaches the maximum value of 20.

[0021] A further improvement to the technical solution of the present invention lies in the following design method for the inductor and capacitor in the DC-DC converter:

[0022] The first inductor L1, the second inductor L2, and the third inductor L3 are designed as follows:

[0023]

[0024] Where R is the equivalent resistive load connected to the DC-DC converter, δ1, δ2, and δ3 are the current ripple coefficients of the first inductor L1, the second inductor L2, and the third inductor L3, respectively, and f s d1 is the switching frequency of the DC-DC converter; d2 is the duty cycle of the first switch T1; d2 is the duty cycle of the second switch T2.

[0025] The first capacitor C1 is designed as follows:

[0026]

[0027] Where γ1 is the voltage ripple coefficient of the first capacitor C1;

[0028] First output capacitor C 1o Second output capacitor C 2o They are designed as follows:

[0029]

[0030]

[0031] Where, γ 1o The first output capacitor C 1o Voltage ripple coefficient; γ 2o For the second output capacitor C 2o Voltage ripple coefficient.

[0032] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows:

[0033] This invention enables the DC-DC converter to perform both boost and buck functions in both single-potential and superimposed-potential operation modes by controlling the duty cycle d1 of the first switch T1 and the duty cycle d2 of the second switch T2. Particularly in the superimposed-potential operation mode, the DC-DC converter can achieve an output voltage U... o It is continuously adjustable within the range of 0 to 20 times the input power supply voltage E, achieving a high-gain voltage output capability of 20 times. It is suitable for industrial applications with a wide input voltage range and high output voltage gain, such as photovoltaic power generation systems, energy storage systems, and electric vehicle charging. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1This is a circuit diagram of a wide-range high-gain DC-DC converter with superimposed potential provided in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the working mode I under the single potential operation mode in an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the working mode II under the single potential operation mode in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the voltage gain in the single-potential operation mode in an embodiment of the present invention;

[0039] Figure 5 This is a simplified circuit diagram of the potential superposition operation mode in an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of working mode I under the potential superposition operation mode in an embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram of the working mode II under the potential superposition operation mode in the embodiment of the present invention;

[0042] Figure 8 This is a schematic diagram of working mode III under the potential superposition operation mode in an embodiment of the present invention;

[0043] Figure 9 This is a schematic diagram of the working mode IV under the potential superposition operation mode in the embodiment of the present invention;

[0044] Figure 10 This is a schematic diagram of the voltage gain in the potential superposition operation mode in an embodiment of the present invention. Detailed Implementation

[0045] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0048] like Figure 1 As shown, a wide-range, high-gain DC-DC converter with superimposed potentials is disclosed. The DC-DC converter consists of a DC input power supply E, a first inductor L1, a first switching transistor T1, a first capacitor C1, a second inductor L2, a diode D1, and a first output capacitor C. 1o The third inductor L3, the second switch T2, the third switch T3, the fourth switch T4, and the second output capacitor C 2o Composition: With the cooperation of the first switch T1, the second switch T2, the third switch T3, and the fourth switch T4, the DC-DC converter has a single-potential operation mode and a potential superposition operation mode, and both operation modes have boost and buck functions; in the single-potential operation mode, the first output capacitor C... 1o The output voltage U is supported by the potential at both ends. o In the superposition of potentials operating mode, the first output capacitor C 1o The potential at both ends and the second output capacitor C 2o The sum of the potentials at both ends supports the output voltage U o .

[0049] The components in the DC-DC converter are connected as follows: the positive terminal of the DC input power supply E is connected to one end of the first inductor L1; the other end of the first inductor L1 is connected to the collector of the first switching transistor T1 and one end of the first capacitor C1; the other end of the first capacitor C1 is connected to the anode of the diode D1 and one end of the second inductor L2; the cathode of the diode D1 is connected to the first output capacitor C... 1o One end, the second output capacitor C 2o One end of the second inductor L3 is connected to the collector of the fourth switch T4 and one end of the third inductor L3; the other end of the third inductor L3 is connected to the collector of the second switch T2 and the collector of the third switch T3; the second output capacitor C 2o The other end is connected to the emitter of the fourth switch T4, the emitter of the third switch T3, and the output voltage U. o The positive terminal of the DC input power supply E is connected to the emitter of the first switching transistor T1, the other end of the second inductor L2, and the first output capacitor C. 1o At the other end, the emitter of the second switch T2 and the output voltage U o The negative extremes are connected.

[0050] When the DC-DC converter operates in single-potential mode, the first switch T1 operates at high frequency, the second and third switches T2 and T3 remain off, and the fourth switch T4 remains on. The operating mode I in single-potential mode is as follows: Figure 2 As shown, when the first switch T1 is turned on, the DC input power supply E charges the first inductor L1 through the first switch T1, and the first capacitor C1 charges the second inductor L2 through the first switch T1. The first output capacitor C1o The load is powered through the fourth switch T4.

[0051] Operating mode II under single potential operation mode, such as Figure 3 As shown, when the first switch T1 is turned off, the DC input power supply E and the first inductor L1 charge the first capacitor C1 in series, and charge the first output capacitor C through diode D1. 1o Charging is achieved by supplying power to the load via the fourth switch T4; the second inductor L2 supplies power to the first output capacitor C via diode D1. 1o It charges and then supplies power to the load through the fourth switch T4.

[0052] The ratio of the conduction time of the first switch T1 to the total switching cycle time is the duty cycle d1. Then, the volt-second balance equations for the first inductor L1 and the second inductor L2 are as follows:

[0053]

[0054] U C1 Let C1 be the voltage across the first capacitor C1. Further, the circuit gain M1 in single-potential operation mode can be obtained as:

[0055]

[0056] Based on equation (3), the voltage gain diagram for the single-potential operation mode is as follows: Figure 4 As shown, by adjusting the value of the duty cycle d1, the voltage gain M1 can be continuously varied within the range of 0 to 4.

[0057] When the DC-DC converter operates in the potential superposition mode, both the first switch T1 and the second switch T2 operate at high frequency, the third switch T3 remains on, and the fourth switch T4 remains off; the first output capacitor C 1o Second output capacitor C 2o A simplified schematic diagram of the second switch T2, the third switch T3, and the third inductor L3 is shown below. Figure 5 As shown in (a) and (b) in the figure.

[0058] Operating mode I under the superposition of potentials is as follows Figure 6 As shown, the first switch T1 and the second switch T2 are turned on. The DC input power supply E charges the first inductor L1 through the first switch T1, and the first capacitor C1 charges the second inductor L2 through the first switch T1. The first output capacitor C... 1o The third inductor L3 is charged through the second switch T2; the first output capacitor C 1o Second output capacitor C 2o The superimposed potentials supply power to the load.

[0059] Operating mode II under the superposition of potentials is as follows Figure 7 As shown, the first switch T1 and the third switch T3 are turned on, the second switch T2 is turned off, the DC input power supply E charges the first inductor L1 through the first switch T1, and the first capacitor C1 charges the second inductor L2 through the first switch T1; the first output capacitor C... 1o The third inductor L3, connected in series with the third inductor L3, supplies power to the load through the third switch T3; the third inductor L3 supplies power to the second output capacitor C through the third switch T3. 2o Charge.

[0060] Operating mode III under the superposition of potentials, such as Figure 8 As shown, the first switch T1 and the third switch T3 are off, the second switch T2 is on, the DC input power supply E and the first inductor L1 are connected in series to charge the first capacitor C1, and then charge the first output capacitor C through diode D1. 1o Charging is achieved by charging the third inductor L3 through the second switch T2; DC input power supply E, first inductor L1, and second output capacitor C 2o The load is powered in series with diode D1; the second inductor L2 supplies power to the first output capacitor C through diode D1. 1o While charging, the second output capacitor C 2o They are connected in series to supply power to the load.

[0061] Operating mode IV under the superposition of potentials is as follows Figure 9 As shown, the first switch T1 and the second switch T2 are off, and the third switch T3 is on. The DC input power supply E and the first inductor L1 are connected in series to charge the first capacitor C1, and charge the first output capacitor C through diode D1. 1o Charging; the DC input power supply E, the first inductor L1, and the third inductor L3 are connected in series and then supply power to the load through diode D1 and the third switch T3; the third inductor L3 supplies power to the second output capacitor C through the third switch T3. 2o Charging; the second inductor L2 supplies power to the first output capacitor C through diode D1. 1o The circuit is charged, and then connected in series with the third inductor L3 to supply power to the load through the third switch T3.

[0062] If the ratio of the conduction time of the second switch T2 to the total switching cycle time is the duty cycle d2, then the volt-second balance equation for the third inductor L3 is:

[0063] d2U C1o =U C2o (1-d2) (3)

[0064] U C2o For the second output capacitor C 2o The voltage across the terminals. Furthermore, the second output capacitor C in the potential superposition operation mode can be obtained. 2oThe gain M2 of the voltage across the terminals is:

[0065]

[0066] Furthermore, the overall voltage gain M of the DC-DC converter in the potential superposition operation mode can be obtained as:

[0067]

[0068] For DC-DC converters, due to parasitic parameters in the actual circuit, problems such as increased losses and difficulty in increasing gain may occur when the duty cycle exceeds 0.8. Therefore, 0.8 is taken as the maximum duty cycle and substituted into the single-potential operation mode gain expression shown in equation (3), the corresponding gain M1 is 4. Furthermore, both the single-potential operation mode and the potential superposition operation mode have boost and buck functions, but considering the switching loss problem, the DC-DC converter operates in the single-potential operation mode when the voltage gain is not greater than 4; and in the case where the voltage gain is greater than 4, the DC-DC converter operates in the potential superposition operation mode. When the duty cycle d1 of the first switch T1 and the duty cycle d2 of the second switch T2 are both 0.8, the voltage gain of the DC-DC converter reaches the maximum value of 20, as shown in equation (3). Figure 10 As shown.

[0069] This invention provides a design method for inductors and capacitors in DC-DC converters as follows:

[0070] The first inductor L1, the second inductor L2, and the third inductor L3 are designed as follows:

[0071]

[0072] Where R is the equivalent resistive load connected to the DC-DC converter, δ1, δ2, and δ3 are the current ripple coefficients of the first inductor L1, the second inductor L2, and the third inductor L3, respectively, and f s This represents the switching frequency of the DC-DC converter.

[0073] The first capacitor C1 is designed as follows:

[0074]

[0075] Wherein, γ1 is the voltage ripple coefficient of the first capacitor C1.

[0076] First output capacitor C 1o Second output capacitor C 2o They are designed as follows:

[0077]

[0078]

[0079] Where, γ1o and γ 2o The first output capacitor C 1o Second output capacitor C 2o Voltage ripple coefficient.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A potential superimposable wide range high gain DC converter characterized by, The DC-DC converter includes a DC input power supply E and a first inductor. First switching transistor First capacitor Second inductor Diode D1, First output capacitor C 1o The third inductor L3, the second switch T2, the third switch T3, the fourth switch T4, and the second output capacitor C 2o With the cooperation of the first switch T1, the second switch T2, the third switch T3, and the fourth switch T4, the DC-DC converter has a single-potential operating mode and a potential superposition operating mode, and both operating modes have boost and buck functions; in the single-potential operating mode, the first output capacitor C... 1o The output voltage is supported by the potential at both ends. In the potential superposition operation mode, the first output capacitor C 1o The potential at both ends and the second output capacitor C 2o The sum of the potentials at both ends supports the output voltage. ; The connection mode of each component in the direct current converter is: the positive terminal of the direct current input power source E is connected with one end of the first inductor L1; the other end of the first inductor L1 is connected with the collector of the first switch tube T1 and one end of the first capacitor C1; the other end of the first capacitor C1 is connected with the anode of the diode D1 and one end of the second inductor L2; the cathode of the diode D1 is connected with one end of the first output capacitor C 1o , one end of the second output capacitor C 2o , the collector of the fourth switch tube T4 and one end of the third inductor L3; the other end of the third inductor L3 is connected with the collector of the second switch tube T2 and the collector of the third switch tube T3; the other end of the second output capacitor C 2o is connected with the emitter of the fourth switch tube T4, the emitter of the third switch tube T3 and the positive terminal of the output voltage U o ; the negative terminal of the direct current input power source E is connected with the emitter of the first switch tube T1, the other end of the second inductor L2, the other end of the first output capacitor C 1o , the emitter of the second switch tube T2 and the negative terminal of the output voltage U .

2. A potential superimposable wide range high gain DC converter as claimed in claim 1, wherein, The single-potential operation mode is characterized in that the first switch T1 is in high-frequency operation, the second switch T2 and the third switch T3 are kept off, and the fourth switch T4 is kept on; the first output capacitor C 1o The two-terminal potential of the second output capacitor C 2o The two-terminal potential of the second output capacitor C The value of the output voltage 1o The two-terminal potential of the second output capacitor C 3. A potential superimposable wide range high gain DC converter as claimed in claim 2, wherein, The single-potential operation mode has the following two working modes: The working mode I is that the first switch tube T1 is turned on, the direct current input power supply E charges the first inductor L1 through the first switch tube T1, the first capacitor C1 charges the second inductor L2 through the first switch tube T1, the first output capacitor C 1o The fourth switch tube T4 is turned on to supply power to the load. The working mode II is: the first switch tube T1 is off, the DC input power E and the first inductor L1 charge the first capacitor C1 in series, the first output capacitor C 1o is charged through the diode D1, and the load is supplied with power through the fourth switch tube T4; the second inductor L2 charges the first output capacitor C 1o through the diode D1, and the load is supplied with power through the fourth switch tube T4.

4. The potential superimposable wide range high gain DC converter according to claim 2, wherein, In the single-potential operation mode, the voltage gain can be continuously changed in the range of 0-4 by adjusting the value of the duty cycle d1.

5. The potential superimposable wide range high gain DC converter according to claim 1, characterized in that, The potential superposition operation mode is that the first switch tube T1 and the second switch tube T2 are high-frequency operated, the third switch tube T3 is kept on, and the fourth switch tube T4 is kept off, and the first output capacitor C 1o and the second output capacitor C 2o are both established, and the output voltage is equal to the sum of the potential across the first output capacitor C 1o and the potential across the second output capacitor C 2o .

6. A potential superimposable wide range high gain DC converter as claimed in claim 5, wherein, The potential superposition operation mode has the following four working modes: Operating mode I is as follows: First switch T1 and second switch T2 are turned on. The DC input power supply E charges the first inductor L1 through the first switch T1, and the first capacitor C1 charges the second inductor L2 through the first switch T1. The first output capacitor C... 1o The third inductor L3 is charged through the second switch T2; the first output capacitor C 1o Second output capacitor C 2o The superimposed potentials supply power to the load; The working mode II is: the first switch tube T1 and the third switch tube T3 are turned on, the second switch tube T2 is turned off, the direct current input power supply E charges the first inductor L1 through the first switch tube T1, and the first capacitor C1 charges the second inductor L2 through the first switch tube T1; the first output capacitor C 1o And the third inductor L3 are connected in series and then supply power to the load through the third switch tube T3; the third inductor L3 charges the second output capacitor C 2o Through the third switch tube T3. The working mode III is: the first switch tube T1 and the third switch tube T3 are turned off, the second switch tube T2 is turned on, the direct current input power supply E and the first inductor L1 are connected in series to charge the first capacitor C1, and then the first output capacitor C 1o is charged through the diode D1, the third inductor L3 is charged through the second switch tube T2; the direct current input power supply E, the first inductor L1 and the second output capacitor C 2o are connected in series to supply power to the load through the diode D1; the second inductor L2 supplies power to the first output capacitor C 1o through the diode D1 while charging the second output capacitor C 2o in series to supply power to the load; The working mode IV is: the first switch T1 and the second switch T2 are off, the third switch T3 is on, the DC input power E and the first inductor L1 are connected in series to charge the first capacitor C1, and the first output capacitor C 1o charging; the DC input power E, the first inductor L1 and the third inductor L3 are connected in series to supply power to the load through the diode D1 and the third switch T3; the third inductor L3 supplies power to the second output capacitor C 2o charging; the second inductor L2 supplies power to the first output capacitor C 1o charging, and then supplies power to the load through the third switch T3 after being connected in series with the third inductor L3.

7. A potential superimposable wide range high gain DC converter as claimed in claim 5, wherein, In the case where the voltage gain is greater than 4, the DC converter operates in the potential superposition operation mode, and when the duty cycle d1 of the first switch tube T1 and the duty cycle d2 of the second switch tube T2 are both 0.8, the voltage gain of the DC converter reaches a maximum value of 20.

8. The potential superimposable wide range high gain DC converter according to claim 1, characterized by, The design method of the inductance and capacitance in the DC converter is as follows: The first inductance L1, the second inductance L2 and the third inductance L3 are respectively designed as: (6) (7) (8) Wherein, R is the equivalent resistance load connected to the DC converter, δ1, δ2 and δ3 are the current ripple coefficients of the first inductor L1, the second inductor L2 and the third inductor L3 respectively, f s is the switching frequency of the DC converter; d1 is the duty cycle of the first switch T1; d2 is the duty cycle of the second switch T2; The first capacitance C1 is designed as: (9) Wherein, γ1 is the voltage ripple coefficient of the first capacitance C1; a first output capacitor C 1o and a second output capacitor C 2o are designed respectively as: (10) (11) where γ 1o is the voltage ripple coefficient of the first output capacitor C 1o ; and γ 2o is the voltage ripple coefficient of the second output capacitor C 2o .

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