Quadratic Boost converter with high gain and low output ripple voltage

Abstract

The invention relates to the field of electrical technology, and discloses a high-gain low-output ripple voltage quadratic Boost converter, which comprises a first switching tube, a second switching tube, a first inductor, a second inductor, a third inductor, a first diode, a second diode, a third diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a load resistor and a power supply module, the second diode, the third diode, the second capacitor and the third capacitor jointly form a voltage multiplication unit; the third inductor and the fourth capacitor jointly form a low-pass filter; the quadratic Boost converter provided by the invention has a higher secondary voltage gain ratio, and can work in a wider output voltage range; meanwhile, continuous current input is achieved, and the filtering requirement of an input port is greatly lowered; secondly, continuous output current is provided, and the stress of the current on an output capacitor is reduced; and the output end of the converter is in cascade connection with a low-pass filter, so that output voltage ripples are reduced.

Description

Technical Field

[0001] The invention relates to the field of electrical technology, and in particular to a secondary Boost converter with high gain and low output ripple voltage. Background Art

[0002] DC-DC converters are widely used in renewable energy systems, transportation, industry, medical treatment, photovoltaic power generation, uninterruptible power supply, mobile phones, LED products and other fields. The development of new technologies requires the converter to have a higher output voltage. In theory, the traditional boost converter can obtain a higher voltage gain through a large duty cycle. However, in practice, the voltage gain of the traditional boost converter circuit cannot achieve the ideal effect because it is affected by the parasitic resistance of the switch tube, inductor and capacitor. In view of the above problems, multi-stage high-gain converters and magnetic coupling-based converters are studied. The multi-stage high-gain converter improves the voltage gain ratio by cascading without increasing the duty cycle, but the circuit topology increases the loss and voltage stress of the switching device in the cascade; the converter based on magnetic coupling has a larger input current ripple. In recent years, various secondary boost converters have been newly developed with higher boost capability to meet this demand. However, the traditional secondary boost converter has the problems of discontinuous output current, increased output voltage ripple caused by discontinuous output current, higher voltage stress of the switching device and lower voltage gain. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a high-gain and low output ripple voltage secondary Boost converter, which is used to solve the problems of high voltage ripple caused by discontinuous output current, high voltage stress of switching devices and low voltage increase in traditional secondary Boost converters.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0005] A high-gain, low-output-ripple-voltage quadratic Boost converter comprises: a first switch tube, a second switch tube, a first inductor, a second inductor, a third inductor, a first diode, a second diode, a third diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a load resistor and a power module;

[0006] The second diode, the third diode, the second capacitor, and the third capacitor together constitute a voltage multiplication unit, which is used to increase the voltage gain of the secondary Boost converter with high gain and low output ripple voltage;

[0007] The third inductor and the fourth capacitor together form a low-pass filter, which is used to reduce the voltage ripple at the output end of the high-gain and low-output ripple voltage quadratic Boost converter;

[0008] The positive electrode of the power supply module is respectively connected to one end of the first inductor and one end of the second inductor, the other end of the second inductor is respectively connected to one end of the second capacitor, one end of the first switch tube, and the positive electrode of the third diode, the negative electrode of the third diode is respectively connected to one end of the third inductor and one end of the third capacitor, the other end of the third inductor is respectively connected to one end of the fourth capacitor and one end of the load resistor, the other end of the first inductor is respectively connected to one end of the first capacitor and one end of the second switch tube, the other end of the first capacitor is respectively connected to the other end of the first switch tube and the positive electrode of the first diode, the other end of the second capacitor is respectively connected to the positive electrode of the second diode, the other end of the fourth capacitor, and the other end of the load resistor, and the negative electrode of the power supply module is respectively connected to the other end of the second switch tube, the negative electrode of the first diode, the negative electrode of the second diode, and the other end of the third capacitor.

[0009] The present invention has the following beneficial effects:

[0010] The high-gain, low-output-ripple-voltage quadratic Boost converter proposed in the present invention has a higher quadratic voltage gain ratio and can operate within a wider output voltage range; it also has a continuous input current, which greatly reduces the filtering requirements of the input port; secondly, it has a continuous output current, which reduces the stress of the current on the output capacitor; and a low-pass filter is cascaded at the output end of the converter, which reduces the output voltage ripple. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of the structure of a high-gain, low-output-ripple-voltage quadratic Boost converter proposed by the present invention;

[0012] Figure 2 Schematic diagram of the equivalent circuit structure of a quadratic Boost converter with high gain and low output ripple voltage when the first switch tube and the second switch tube are synchronously turned on in the embodiment;

[0013] Figure 3 Schematic diagram of the equivalent circuit structure of a quadratic Boost converter with high gain and low output ripple voltage when the first switch tube and the second switch tube are synchronously disconnected in the embodiment. DETAILED DESCRIPTION

[0014] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0015] like Figure 1 As shown, a high-gain low-output-ripple-voltage quadratic Boost converter comprises: a first switch tube, a second switch tube, a first inductor, a second inductor, a third inductor, a first diode, a second diode, a third diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a load resistor and a power module; the second diode, the third diode, the second capacitor and the third capacitor together constitute a voltage multiplication unit for improving the voltage gain of the high-gain low-output-ripple-voltage quadratic Boost converter; the third inductor and the fourth capacitor together constitute a low-pass filter for reducing the voltage ripple at the output end of the high-gain low-output-ripple-voltage quadratic Boost converter; the positive electrode of the power module is respectively connected to one end of the first inductor and one end of the second inductor, and the other end of the second inductor is respectively connected to the positive electrode of the power module. The first and second capacitors are connected to one end of the second capacitor, one end of the first switch tube, and the positive electrode of the third diode. The negative electrode of the third diode is respectively connected to one end of the third inductor and one end of the third capacitor. The other end of the third inductor is respectively connected to one end of the fourth capacitor and one end of the load resistor. The other end of the first inductor is respectively connected to one end of the first capacitor, one end of the second switch tube, and the other end of the first capacitor is respectively connected to the other end of the first switch tube and the positive electrode of the first diode. The other end of the second capacitor is respectively connected to the positive electrode of the second diode, the other end of the fourth capacitor, and the other end of the load resistor. The negative electrode of the power module is respectively connected to the other end of the second switch tube, the negative electrode of the first diode, the negative electrode of the second diode, and the other end of the third capacitor.

[0016] In this embodiment, Figure 1 Medium S 1 , S 2 Respectively represent the first switch tube and the second switch tube, L 1 , L 2 , L 3 Respectively represent the first inductance, the second inductance, and the third inductance, C 1 , C 2 , C 3 、c 0 Respectively represent the first capacitor, the second capacitor, the third capacitor, and the fourth capacitor, D 1, D 2 , D 3 Respectively represent the first diode, the second diode, and the third diode, R L represents the load resistance, V i The input voltage of the high-gain, low-output-ripple-voltage quadratic boost converter, V 0 represents the output voltage of the high-gain and low-output-ripple-voltage quadratic Boost converter. 1 , the second inductor L 2 is the energy storage inductor, the first inductor L 1 The function of the second inductor L is to provide energy to the input voltage during the on-time of the switch tube and to charge the first capacitor during the off-time of the switch tube. 2 The function of the first capacitor C is to store energy during the on-time of the switch tube and to supply energy to the second capacitor and the third capacitor during the off-time of the switch tube; 1 The function of D is to supply energy to the second inductor together with the output voltage during the on-time of the switch tube; the function of the first diode is to provide a path during the off-time of the switch tube; at the same time, D 2 , D 3 , C 2 , C 3 Together they form a voltage multiplication unit, which is used to increase the voltage gain of a high-gain, low-output-ripple-voltage secondary Boost converter; L 3 , C 0 A low-pass filter is formed to reduce the voltage ripple at the output end of a high-gain, low-output ripple voltage quadratic Boost converter.

[0017] In addition, in order to simplify the working principle of the high-gain and low-output-ripple-voltage quadratic Boost converter, the following conditions are assumed: (1) All diodes, switches, inductors, and capacitors in the converter are ideal devices; (2) The first switch S 1 , the second switch tube S 2 The synchronous switching period is T s , and the synchronous switching frequency is f s , the synchronous switching frequency is much greater than the characteristic frequency of the high-gain and low-output-ripple-voltage quadratic Boost converter; (3) all inductor currents of the high-gain and low-output-ripple-voltage quadratic Boost converter operate in continuous conduction mode (CCM); (4) the second capacitor and the third capacitor are equal, that is: C 2 =C 3 =C.

[0018] like Figure 2As shown, when the first switch tube and the second switch tube are synchronously turned on, the equivalent circuit of the high-gain low output ripple voltage quadratic Boost converter includes: a power module, a first switch tube, a second switch tube, a first inductor, a second inductor, a third inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and a load resistor; the positive electrode of the power module is respectively connected to one end of the first inductor and one end of the second inductor, the other end of the second inductor is respectively connected to one end of the first switch tube and one end of the second capacitor, the other end of the second capacitor is respectively connected to one end of the fourth capacitor and one end of the load resistor, the other end of the first inductor is respectively connected to one end of the first capacitor and one end of the second switch tube, the other end of the first capacitor is connected to the other end of the first switch tube, the negative electrode of the power module is respectively connected to the other end of the second switch tube and one end of the third capacitor, the other end of the third capacitor is connected to one end of the third inductor, and the other end of the third inductor is respectively connected to the other end of the fourth capacitor and the other end of the load resistor.

[0019] In this embodiment, Figure 2 The equivalent circuit structure of the quadratic Boost converter with high gain and low output ripple voltage when the first switch tube and the second switch tube are synchronously turned on is shown. The principle is: in the on state (0~DT s ): The first switch tube S 1 , the second switch tube S 2 Synchronous conduction, by Figure 2 It can be seen that the input voltage V of the quadratic Boost converter with high gain and low output ripple voltage is i The first inductor L 1 charging, so that the first inductor L 1 The current rises linearly due to the first diode D 1 Withstands reverse voltage and turns off, storing energy in the first capacitor C 1 and input voltage V i The second inductor L 2 Charging, the second inductor L 2 The current rises linearly; at the same time, the energy storage first capacitor C 1 and the second energy storage capacitor C 2 , the third capacitor C 3 Connect in series to give the third inductor L 3 and load resistance R L Provides energy to keep the output voltage stable. The third inductor L 3 The current rises, the second diode D 2 , the third diode D 3It is turned off due to the reverse bias voltage (provided by the voltage of the second capacitor and the third capacitor); therefore, according to the working principle of this stage, the corresponding equation can be established as follows:

[0020] like Figure 3 As shown, when the first switch tube and the second switch tube are synchronously disconnected, the equivalent circuit of the high-gain low output ripple voltage quadratic Boost converter includes: a power module, a first inductor, a second inductor, a third inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first diode, a second diode, a third diode and a load resistor; the positive electrode of the power module is respectively connected to one end of the first inductor and one end of the second inductor, the other end of the second inductor is respectively connected to one end of the second capacitor and the positive electrode of the third diode, the negative electrode of the third diode is respectively connected to one end of the third capacitor and one end of the third inductor, the other end of the third inductor is respectively connected to one end of the fourth capacitor and one end of the load resistor, the other end of the first inductor is connected to one end of the first capacitor, the other end of the first capacitor is connected to the positive electrode of the first diode, the other end of the second capacitor is respectively connected to the positive electrode of the second diode, the other end of the fourth capacitor and the other end of the load resistor, and the negative electrode of the power module is respectively connected to the negative electrode of the first diode, the negative electrode of the second diode and the other end of the third capacitor.

[0021] In this embodiment, Figure 3 The equivalent circuit structure of a high-gain, low-output-ripple-voltage quadratic Boost converter is shown in the figure. The principle is: in the on state (DT s ~T s ): The first switch tube S 1 , the second switch tube S 2 Synchronous shutdown by Figure 3 It can be seen that the first diode D 1 The voltage it bears is the forward voltage and turns on. The second diode D 2 Withstands reverse voltage and turns off, stored in the first inductor L 1 The energy and input voltage V i Through the first diode D 1 Common to the first capacitor C 1 Charging, first inductor L 1 The current of the second diode D 2 , the third diode D 3 Withstands forward voltage and conducts, input voltage V i and the second inductor L 2 For the second capacitor C 2 and the third capacitor C3 Charging, the third inductor L 3 to the load resistor and the second capacitor C 2 and the third capacitor C 3 3 discharge, the second inductor L 2 , the third inductor L 3 The current decreases linearly due to the second diode D 2 , the third diode D 3 The second capacitor C 2 and the third capacitor C 3 Charge in parallel and consider that the capacitance values ​​of the second capacitor and the third capacitor are equal, that is: C 2 =C 3 =C, we can get According to the working principle of this stage, the corresponding equation can be established as follows:

[0022] Therefore, according to the volt-second balance principle and taking into account By formula

[0023] We can get: The voltage gain ratio of the high-gain and low-output-ripple-voltage quadratic Boost converter can be obtained from this formula, namely:

[0024]

[0025] Where M represents the voltage gain ratio of the high-gain and low-output-ripple-voltage quadratic Boost converter, D represents the duty cycle of the synchronous conduction of the first and second switch tubes, V 0 The output voltage of the high-gain, low-output-ripple-voltage quadratic boost converter, V i Represents the input voltage of a high-gain, low-output-ripple-voltage quadratic boost converter.

[0026] At the same time, the voltage stress of the switching device is analyzed to provide theoretical support for the selection of the switching device, as follows:

[0027] According to the voltage stress of the switch tube, which is the voltage value that the switch tube bears when it is in the disconnected state, it can be obtained:

[0028] When the first switch tube and the second switch tube are turned on synchronously, the voltage stress of the first switch tube is equal to the voltage stress of the first capacitor, and the voltage stress of the second switch tube is equal to the voltage stress of the second capacitor, specifically:

[0029]

[0030] in, represents the voltage stress of the first switch tube, represents the voltage stress of the second switch tube, represents the voltage stress of the first capacitor, represents the voltage stress of the second capacitor.

[0031] In addition, according to the working principle of the high-gain and low-output-ripple-voltage secondary Boost converter, the first diode D 1 , the second diode D 2 , the third diode D 3 The voltage stress is the voltage value in the on state, so:

[0032] When the first switch tube and the second switch tube are synchronously disconnected, the voltage stress of the first diode is equal to the voltage stress of the first capacitor, the voltage stress of the second diode is equal to the voltage stress of the third diode and is equal to the sum of the voltage stresses of the first capacitor and the second capacitor, specifically:

[0033]

[0034] in, represents the voltage stress of the first diode, represents the voltage stress of the second diode, represents the voltage stress of the third diode.

[0035] At the same time, the current stress of the switching device is analyzed to provide theoretical support for the selection of the switching device, as shown below:

[0036] Specifically, when the first switch tube and the second switch tube are synchronously turned on, and when the high-gain, low-output-ripple-voltage quadratic Boost converter is in a steady state, based on the capacitor satisfying the ampere-second balance principle, the average current of the first inductor, the second inductor, and the third inductor is calculated, that is:

[0037]

[0038] in, represents the average current of the first inductor, represents the average current of the second inductor, represents the average current of the third inductor, I 0 The average current at the output of a high-gain, low-output-ripple-voltage quadratic boost converter, R L Represents the load resistance.

[0039] Based on the average current of the first inductor, the second inductor, and the third inductor, the current flowing through the second switch tube at the current moment is calculated, that is:

[0040]

[0041] in, represents the current flowing through the second switch tube at time t, N represents the number of switch tube cycles, T S Represents the synchronous switching period, DT S Indicates the conduction time of the switch tube.

[0042] Based on the current flowing through the second switch tube at the current moment, the average current stress flowing through the second switch tube is obtained, that is:

[0043]

[0044] in, Represents the average current stress of the second switching tube.

[0045] Similarly, based on the average current of the second inductor and the third inductor, the average current stress flowing through the first switch tube is obtained, that is:

[0046]

[0047] in, Represents the average current stress of the first switching tube.

[0048] Specifically, when the first switch tube and the second switch tube are synchronously turned off, the current stress of the first diode, the second diode and the third diode is:

[0049]

[0050] in, represents the current stress of the first diode, represents the current stress of the second diode, represents the current stress of the third diode.

[0051] At the same time, the inductor current ripple and critical inductance are analyzed to solve the critical inductance. By solving the critical inductance, it is determined whether the inductor works in the continuous conduction mode. Specifically:

[0052] Assume the inductance L 1 ~L 3 The current ripple is The working principle and

[0053] L 1 ~L 3 The current ripple expression is as follows:

[0054] Specifically, when the first switch tube and the second switch tube are synchronously turned on or synchronously turned off, the current ripples of the first inductor, the second inductor, and the third inductor are:

[0055]

[0056] in, represents the current ripple of the first inductor, represents the current ripple of the second inductor, represents the current ripple of the third inductor, f s represents the synchronous switching frequency, V C Indicates the voltage stress of the second capacitor or the third capacitor, L 1 , L 2 , L 3 They represent the first inductance, the second inductance, and the third inductance respectively.

[0057] When the high-gain, low-output-ripple-voltage quadratic Boost converter operates in a critical condition mode, the minimum current flowing through the inductor is equal to zero. Therefore, the minimum current flowing through the first inductor, the second inductor, and the third inductor is calculated according to the average current of the first inductor, the second inductor, and the third inductor and the current ripple of the first inductor, the second inductor, and the third inductor, that is:

[0058]

[0059] in, represents the minimum current of the first inductor, represents the minimum current of the second inductor, Indicates the minimum current of the third inductor.

[0060] According to the minimum current flowing through the first inductor, the second inductor, and the third inductor, the critical inductance of the first inductor, the second inductor, and the third inductor is obtained as follows:

[0061]

[0062] Among them, L 1B represents the critical inductance of the first inductor, L 2B represents the critical inductance of the second inductor, L 3B represents the critical inductance of the third inductor.

[0063] In this embodiment, from the formula of the critical inductance of the first inductor, the second inductor, and the third inductor: It can be seen that when L 1 >L 1B , L 2 >L 2B , L3 >L 3B When, the quadratic Boost converter with high gain and low output ripple voltage operates in continuous conduction mode (CCM), otherwise, it operates in discontinuous conduction mode (DCM).

[0064] At the same time, the ripple voltage of the capacitor is analyzed to select the capacitor model, and the output voltage ripple of the high-gain quadratic Buck-Boost converter can also be judged according to the output ripple voltage of the fourth capacitor. Specifically:

[0065] Let the first capacitor C 1 、the second capacitor C 2 、the third capacitor C 3 、the fourth capacitor C 0 The output ripple voltages are respectively From the working principle and formula of the quadratic Boost converter with high gain and low output ripple voltage Analysis shows that the output ripple voltages of the first capacitor C 1 、the second capacitor C 2 、the third capacitor C 3 are as follows:

[0066] Specifically, when the first switch tube and the second switch tube are turned on or off synchronously, the ripple voltages of the first capacitor, the second capacitor, the third capacitor, and the fourth capacitor are:

[0067]

[0068] Among them, C represents the second capacitor or the third capacitor, represents the ripple voltage of the first capacitor, respectively represent the ripple voltages of the second capacitor and the third capacitor, represents the ripple voltage of the fourth capacitor, represents the charging charge of the first capacitor, ΔQ C represents the charging charge of the second capacitor or the third capacitor, represents the charging charge of the fourth capacitor, C 0 represents the fourth capacitor, C 1 represents the first capacitor.

[0069] In this embodiment, by comparing the topological structures of the existing converter and the converter proposed in the present invention, the effectiveness of a quadratic Boost converter with high gain and low output ripple voltage proposed in the present invention is verified, as shown in Table 1 specifically:

[0070] Table 1 Comparison table of topological structures of existing converters and converters proposed in the present invention

[0071]

[0072]

[0073] Table 1 shows the comparison of the number of components, voltage gain, voltage stress and current continuity of the traditional quadratic Boost converter, the quadratic Boost converter, the improved high-gain quadratic Boost converter and the Boost converter proposed in the present invention. It can be seen from the comparison results in Table 1 that the Boost converter proposed in the present invention is relatively larger than the traditional quadratic Boost converter, the quadratic Boost converter and the improved high-gain quadratic Boost converter; at the same time, the output voltage gain ratio of the Boost converter proposed in the present invention is significantly greater than that of other converters, and the switch tube stress is significantly reduced under the same output voltage condition, and it has continuous input and output current, which greatly reduces the filtering requirements of the input port and reduces the current stress on the output capacitor; in addition, the output end of the Boost converter proposed in the present invention is cascaded with a low-pass filter, which reduces the output voltage ripple. Therefore, through the above comparison, it can be obtained that the Boost converter proposed in the present invention has better performance.

[0074] In summary, the quadratic Boost converter with high gain and low output ripple voltage proposed in the present invention combines a traditional quadratic Boost converter with a voltage multiplication unit and a low-pass filter to obtain a quadratic Boost converter with high gain and low output ripple voltage. The converter has a higher quadratic voltage gain ratio and can operate within a wider output voltage range. At the same time, it has a continuous input current, which greatly reduces the filtering requirements of the input port. Secondly, it has a continuous output current, which reduces the stress of the current on the output capacitor. In addition, a low-pass filter is cascaded at the output end of the converter to reduce the output voltage ripple.

[0075] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0076] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A high-gain, low-output-ripple-voltage quadratic Boost converter, characterized in that: include: A first switch tube, a second switch tube, a first inductor, a second inductor, a third inductor, a first diode, a second diode, a third diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a load resistor and a power module; The second diode, the third diode, the second capacitor, and the third capacitor together constitute a voltage multiplication unit, which is used to increase the voltage gain of the secondary Boost converter with high gain and low output ripple voltage; The third inductor and the fourth capacitor together form a low-pass filter, which is used to reduce the voltage ripple at the output end of the high-gain and low-output ripple voltage quadratic Boost converter; The positive electrode of the power supply module is respectively connected to one end of the first inductor and one end of the second inductor, the other end of the second inductor is respectively connected to one end of the second capacitor, one end of the first switch tube, and the positive electrode of the third diode, the negative electrode of the third diode is respectively connected to one end of the third inductor and one end of the third capacitor, the other end of the third inductor is respectively connected to one end of the fourth capacitor and one end of the load resistor, the other end of the first inductor is respectively connected to one end of the first capacitor and one end of the second switch tube, the other end of the first capacitor is respectively connected to the other end of the first switch tube and the positive electrode of the first diode, the other end of the second capacitor is respectively connected to the positive electrode of the second diode, the other end of the fourth capacitor, and the other end of the load resistor, and the negative electrode of the power supply module is respectively connected to the other end of the second switch tube, the negative electrode of the first diode, the negative electrode of the second diode, and the other end of the third capacitor.

2. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 1, characterized in that: When the first switch tube and the second switch tube are synchronously turned on, the equivalent circuit of the high-gain and low-output ripple voltage quadratic Boost converter includes: a power module, a first switch tube, a second switch tube, a first inductor, a second inductor, a third inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and a load resistor; the positive electrode of the power module is respectively connected to one end of the first inductor and one end of the second inductor, the other end of the second inductor is respectively connected to one end of the first switch tube and one end of the second capacitor, the other end of the second capacitor is respectively connected to one end of the fourth capacitor and one end of the load resistor, the other end of the first inductor is respectively connected to one end of the first capacitor and one end of the second switch tube, the other end of the first capacitor is connected to the other end of the first switch tube, the negative electrode of the power module is respectively connected to the other end of the second switch tube and one end of the third capacitor, the other end of the third capacitor is connected to one end of the third inductor, and the other end of the third inductor is respectively connected to the other end of the fourth capacitor and the other end of the load resistor.

3. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 2, characterized in that: When the first switch tube and the second switch tube are synchronously disconnected, the equivalent circuit of the high-gain and low-output ripple voltage quadratic Boost converter includes: a power module, a first inductor, a second inductor, a third inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first diode, a second diode, a third diode and a load resistor; the positive electrode of the power module is respectively connected to one end of the first inductor and one end of the second inductor, the other end of the second inductor is respectively connected to one end of the second capacitor and the positive electrode of the third diode, the negative electrode of the third diode is respectively connected to one end of the third capacitor and one end of the third inductor, the other end of the third inductor is respectively connected to one end of the fourth capacitor and one end of the load resistor, the other end of the first inductor is connected to one end of the first capacitor, the other end of the first capacitor is connected to the positive electrode of the first diode, the other end of the second capacitor is respectively connected to the positive electrode of the second diode, the other end of the fourth capacitor and the other end of the load resistor, and the negative electrode of the power module is respectively connected to the negative electrode of the first diode, the negative electrode of the second diode and the other end of the third capacitor.

4. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 3, characterized in that: The voltage gain ratio of the high-gain, low-output-ripple-voltage quadratic Boost converter is: Wherein, M represents the voltage gain ratio of the high-gain and low-output-ripple-voltage quadratic Boost converter, D represents the duty cycle of the synchronous conduction of the first switch tube and the second switch tube, V0 represents the output voltage of the high-gain and low-output-ripple-voltage quadratic Boost converter, V i Represents the input voltage of a high-gain, low-output-ripple-voltage quadratic boost converter.

5. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 4, characterized in that: When the first switch tube and the second switch tube are turned on synchronously, the voltage stress of the first switch tube is equal to the voltage stress of the first capacitor, and the voltage stress of the second switch tube is equal to the voltage stress of the second capacitor, specifically: in, represents the voltage stress of the first switch tube, represents the voltage stress of the second switch tube, represents the voltage stress of the first capacitor, represents the voltage stress of the second capacitor.

6. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 5, characterized in that: When the first switch tube and the second switch tube are synchronously disconnected, the voltage stress of the first diode is equal to the voltage stress of the first capacitor, the voltage stress of the second diode is equal to the voltage stress of the third diode and is equal to the sum of the voltage stresses of the first capacitor and the second capacitor, specifically: in, represents the voltage stress of the first diode, represents the voltage stress of the second diode, represents the voltage stress of the third diode.

7. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 6, characterized in that: When the first switch tube and the second switch tube are synchronously turned on, and when the high-gain low-output ripple voltage quadratic Boost converter is in a steady state, based on the capacitor satisfying the ampere-second balance principle, the average current of the first inductor, the second inductor, and the third inductor is calculated, that is: in, represents the average current of the first inductor, represents the average current of the second inductor, represents the average current of the third inductor, I0 represents the average current at the output of the high-gain and low-output-ripple-voltage quadratic Boost converter, R L represents the load resistance; Based on the average current of the first inductor, the second inductor, and the third inductor, the current flowing through the second switch tube at the current moment is calculated, that is: in, represents the current flowing through the second switch tube at time t, N represents the number of switch tube cycles, T S Represents the synchronous switching period, DT S Indicates the conduction time of the switch tube; Based on the current flowing through the second switch tube at the current moment, the average current stress flowing through the second switch tube is obtained, that is: in, represents the average current stress of the second switch tube; Similarly, based on the average current of the second inductor and the third inductor, the average current stress flowing through the first switch tube is obtained, that is: in, Represents the average current stress of the first switching tube.

8. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 7, characterized in that: When the first switch tube and the second switch tube are synchronously turned off, the current stress of the first diode, the second diode and the third diode is: in, represents the current stress of the first diode, represents the current stress of the second diode, represents the current stress of the third diode.

9. The high-gain, low-output-ripple-voltage quadratic Boost converter according to claim 8, characterized in that: When the first switch tube and the second switch tube are synchronously turned on or turned off, the current ripples of the first inductor, the second inductor and the third inductor are: in, represents the current ripple of the first inductor, represents the current ripple of the second inductor, represents the current ripple of the third inductor, f s represents the synchronous switching frequency, V C represents the voltage stress of the second capacitor or the third capacitor, L1, L2, L3 represent the first inductance, the second inductance, the third inductance respectively; When the high-gain, low-output-ripple-voltage quadratic Boost converter operates in a critical condition mode, the minimum current flowing through the inductor is equal to zero. Therefore, the minimum current flowing through the first inductor, the second inductor, and the third inductor is calculated according to the average current of the first inductor, the second inductor, and the third inductor and the current ripple of the first inductor, the second inductor, and the third inductor, that is: in, represents the minimum current of the first inductor, represents the minimum current of the second inductor, represents the minimum current of the third inductor; According to the minimum current flowing through the first inductor, the second inductor, and the third inductor, the critical inductance of the first inductor, the second inductor, and the third inductor is obtained as follows: Among them, L 1B represents the critical inductance of the first inductor, L 2B represents the critical inductance of the second inductor, L 3B represents the critical inductance of the third inductor.

10. The high-gain secondary Buck-Boost converter for renewable energy according to claim 9, characterized in that: When the first switch tube and the second switch tube are synchronously turned on or turned off, the ripple voltages of the first capacitor, the second capacitor, the third capacitor, and the fourth capacitor are: Wherein, C represents the second capacitor or the third capacitor, represents the ripple voltage of the first capacitor, Respectively represent the ripple voltage of the second capacitor and the third capacitor, represents the ripple voltage of the fourth capacitor, represents the charge of the first capacitor, ΔQ C represents the charge amount of the second capacitor or the third capacitor, represents the charge amount of the fourth capacitor, C0 represents the fourth capacitor, and C1 represents the first capacitor.

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