Common ground type double-tube super-high gain boost converter, control method and application thereof

Abstract

The application belongs to the technical field of converters, and discloses a common ground type double-tube super-high gain boost converter and a control method and application thereof. Under traditional interleaved control, the converter can realize super-high voltage gain far exceeding that of a traditional scheme under a medium duty ratio by using only two switching tubes, and the control is simple. The full common ground design makes driving simple, sampling convenient, and free from high-frequency common-mode interference; voltage stress of each power device is low in a wide duty ratio range, and reliability and efficiency are significantly improved. Compared with an existing transformerless interleaved parallel super-high gain scheme, the application has the advantages of strong boost capability, wide duty ratio low stress, full common ground, and the like, and has a simple structure and controllable cost, overcomes problems of an extreme duty ratio, high stress, or a complex topology of a traditional converter, and is particularly suitable for scenes sensitive to cost, reliability, and efficiency, such as balcony photovoltaic interface and other distributed power generation applications.

Description

Technical Field

[0001] This invention belongs to the field of converter technology, and relates to a common-ground dual-transistor ultra-high gain boost converter, its control method and application. Background Technology

[0002] With the popularization of distributed photovoltaic (PV) power generation, balcony PV systems are gradually becoming an important form of green energy consumption for urban households due to their flexible installation, plug-and-play nature, and lack of complex construction requirements. Balcony PV systems typically consist of one or two PV modules. Due to safety voltage requirements, the module outputs cannot be connected in series for voltage boosting; they must be connected in parallel. The maximum power point voltage is generally maintained between 20 and 50V. In parallel structures, the system input current is relatively large, and the power generation efficiency is particularly sensitive to current ripple. Therefore, strict requirements are placed on the current stress and input current ripple of the converter. Meanwhile, single-phase grid-connected inverters typically need to be connected to a 400V DC bus, which necessitates the installation of an ultra-high gain boost converter with a boost capacity of more than 20 times between the PV modules and the inverter. Furthermore, balcony PV systems place multiple stringent requirements on the interface converter: compact size to adapt to limited installation space, high efficiency to improve power generation revenue, high reliability to meet long-term maintenance-free use, and low cost to suit the residential consumer market. Therefore, developing a boost converter with a simple structure, low current ripple, high efficiency under full load, high voltage gain, and common ground characteristics is of great significance for promoting the large-scale application of balcony photovoltaics.

[0003] In existing technologies, transformerless interleaved parallel high-gain boost converters are widely used due to their advantages such as low input current ripple, low current stress, convenient magnetic component design, and high power density and efficiency. Among these, the capacitor series interleaved parallel structure with common ground characteristics typically increases the voltage gain by increasing the number of phases (i.e., the number of switches). However, balcony photovoltaic systems are limited by safety voltage requirements, and photovoltaic modules can only be connected in parallel. Their maximum power point voltage varies within a wide range of 20-50V depending on factors such as sunlight and temperature, corresponding to a wide duty cycle adjustment range, large input current, and sensitivity to ripple. Under these conditions, the limitations of multi-switch solutions become apparent: on the one hand, increasing the number of switches leads to increased system cost and decreased reliability; on the other hand, the duty cycle operating range for achieving automatic inductor current sharing and maintaining low voltage stress narrows significantly with increasing phase number. When the duty cycle is below 0.75, current sharing capability is lost, voltage stress increases sharply, and voltage gain decreases significantly, making it difficult to adapt to the actual wide-range input requirements of balcony photovoltaic systems. Therefore, how to achieve low-stress operation over a wide duty cycle range with the fewest number of switching transistors while ensuring common ground and high gain has become a key problem that needs to be solved for balcony photovoltaic interface converters. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a common-ground dual-transistor ultra-high gain boost converter and its control method and application. This converter can achieve a much higher voltage gain than traditional schemes with only two switching transistors at a medium duty cycle through traditional interleaved control, and the control is simple.

[0005] In a first aspect of the invention, a common-ground dual-transistor ultra-high gain boost converter is provided, the common-ground dual-transistor ultra-high gain boost converter including a first input inductor L in1 Second input inductor L in2 First input diode D in1 Second input diode D in2 First phase diode D ph1 Second phase diode D ph2 Intermediate capacitor C int First inductor L1, second inductor L2, first diode D1, second diode D2, first switch S1, second switch S2, first capacitor C1, output filter capacitor C o ;

[0006] The first input inductor L in1 The first terminal and the second input inductor L in2 The first terminal is connected as the positive terminal of the input terminal of the common-ground dual-tube ultra-high gain boost converter;

[0007] The intermediate capacitor C int The negative terminal is connected to the source of the first switch S1, the second switch S2, and the output filter capacitor C. o The negative terminal is connected to serve as the negative terminal of both the input and output terminals of the common-ground dual-transistor ultra-high gain boost converter.

[0008] The first input inductor L in1 The second terminal is connected to the first input diode D in1 First phase diode D ph1 Anode connection;

[0009] The second input inductor L in2 The second terminal is connected to the second input diode D in2 Second phase diode D ph2 Anode connection;

[0010] The first input diode D in1 The cathode is connected to the first terminal of the first inductor L1, the first terminal of the second inductor L2, and the second input diode D. in2 Cathode, intermediate capacitor C int The positive terminal connection;

[0011] The first phase diode D ph1The cathode is connected to the second terminal of the first inductor L1, the anode of the first diode D1, and the drain of the first switching transistor S1;

[0012] The second phase diode D ph2 The cathode is connected to the second terminal of the second inductor L2, the negative terminal of the first capacitor C1, and the drain of the second switch S2.

[0013] The cathode of the first diode D1 is connected to the positive terminal of the first capacitor C1 and the anode of the second diode D2;

[0014] The cathode of the second diode D2 and the output filter capacitor C o The positive terminal is connected to the ground and serves as the positive terminal of the output of the common-ground dual-tube ultra-high gain boost converter.

[0015] In some embodiments of the present invention, the first input inductor L in1 With the second input inductor L in2 The inductance values ​​are all L in And satisfy:

[0016] ;

[0017] The inductance values ​​of the first inductor L1 and the second inductor L2 are both L, and they satisfy:

[0018] ;

[0019] In the formula, U in,min Indicates the minimum input voltage; U o Indicates the output voltage; D max This indicates the duty cycle of the switching transistor at the lowest input voltage; f s Indicates the switching frequency; P o,max This indicates the maximum output power.

[0020] In some embodiments of the present invention, the ideal voltage gain G of the common-ground dual-transistor ultra-high gain boost converter is:

[0021] ;

[0022] In the formula, U in This represents the average value of the input voltage.

[0023] A second aspect of the present invention provides a control method for the above-described common-ground dual-transistor ultra-high gain boost converter, the control method comprising the following steps:

[0024] S1. The reference value u of the output voltage of the common-ground dual-transistor ultra-high gain boost converter. o,ref With feedback value u o,f By comparing the results, the error signal e is obtained;

[0025] S2. The error signal e is sent to the PI controller, and after passing through the unidirectional limiting circuit, the modulation signal u is obtained. r ;

[0026] S3. Modulate the signal u r Each is respectively with the first unipolar triangular carrier u c1 Second unipolar triangular carrier u c2 After the cutoff, the drive signal u of the first switch S1 is obtained. gs,S1 The drive signal u of the second switch S2 gs,S2 The first unipolar triangular carrier u c1 With the second unipolar triangular carrier u c2 The amplitude of all are U cm The frequency is the same as f s The phases are 180° apart.

[0027] A third aspect of the present invention provides the application of the above-mentioned common-ground dual-tube ultra-high gain boost converter in a balcony photovoltaic interface scenario.

[0028] In a fourth aspect, the present invention provides a boost converter for a balcony photovoltaic interface, wherein the boost converter is the aforementioned common-ground dual-tube ultra-high gain boost converter; the input terminal of the boost converter is connected to the photovoltaic module; and the output terminal of the boost converter is connected to a single-phase grid-connected inverter.

[0029] In some embodiments of the present invention, the photovoltaic module is in the form of a single or multiple modules connected in parallel, and its maximum power point voltage range is 20~50V; the rated AC output voltage of the single-phase grid-connected inverter is 230V.

[0030] Compared with the prior art, the technical solution provided by the present invention has the following technical effects:

[0031] (1) The common-ground dual-tube ultra-high gain boost converter proposed in this invention achieves a balance between ultra-high gain and medium duty cycle, that is, ultra-high gain can be achieved under medium duty cycle, avoiding the efficiency reduction and stability problems caused by the extreme duty cycle required by traditional high gain converters.

[0032] (2) The common-ground dual-transistor ultra-high gain boost converter proposed in this invention has fewer switching transistors. At the same time, it has low voltage and current stress, can use low-voltage devices, effectively reduce cost and loss, and improve system efficiency. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the circuit structure of a common-ground dual-transistor ultra-high gain boost converter provided in an embodiment of the present invention;

[0035] Figure 2 for Figure 1 A schematic diagram of the control method for a common-ground dual-transistor ultra-high gain boost converter is shown.

[0036] Figures 3 to 5 for Figure 1 The diagram shows the equivalent circuit diagrams of each mode of the common-ground dual-transistor ultra-high gain boost converter during one switching cycle in steady-state operation.

[0037] Figure 6 for Figure 1 The diagram shows the main waveforms of the common-ground dual-transistor ultra-high gain boost converter during one switching cycle in steady-state operation.

[0038] Figures 7 to 10 for Figure 1 The steady-state simulation waveform of the common-ground dual-transistor ultra-high gain boost converter is shown. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this invention.

[0040] Figure 1 This is a schematic diagram of a common-ground dual-transistor ultra-high gain boost converter circuit provided in an embodiment of the present invention. The common-ground dual-transistor ultra-high gain boost converter includes a first input inductor L. in1 Second input inductor L in2 First input diode D in1 Second input diode D in2 First phase diode D ph1 Second phase diode D ph2 Intermediate capacitor C intFirst inductor L1, second inductor L2, first diode D1, second diode D2, first switch S1, second switch S2, first capacitor C1, output filter capacitor C o The first input inductor L in1 The first terminal and the second input inductor L in2 The first terminal is connected as the positive terminal of the input of the common-ground dual-transistor ultra-high gain boost converter; the intermediate capacitor C int The negative terminal is connected to the source of the first switch S1, the second switch S2, and the output filter capacitor C. o The negative terminal of the input is connected, serving as the negative terminal of both the input and output terminals of the common-ground dual-transistor ultra-high gain boost converter; the first input inductor L in1 The second terminal is connected to the first input diode D in1 First phase diode D ph1 The anode connection; the second input inductor L in2 The second terminal is connected to the second input diode D in2 Second phase diode D ph2 Anode connection; the first input diode D in1 The cathode is connected to the first terminal of the first inductor L1, the first terminal of the second inductor L2, and the second input diode D. in2 Cathode, intermediate capacitor C int The positive terminal is connected; the first phase diode D ph1 The cathode of the first inductor L1 is connected to the second terminal of the first inductor L1, the anode of the first diode D1, and the drain of the first switching transistor S1; the second phase diode D... ph2 The cathode of the first diode D1 is connected to the second terminal of the second inductor L2, the negative terminal of the first capacitor C1, and the drain of the second switch S2; the cathode of the first diode D1 is connected to the positive terminal of the first capacitor C1 and the anode of the second diode D2; the cathode of the second diode D2 is connected to the output filter capacitor C... o The positive terminal is connected to the ground and serves as the positive terminal of the output of the common-ground dual-tube ultra-high gain boost converter.

[0041] like Figure 2 As shown, this embodiment of the invention provides a control method for the above-mentioned common-ground dual-transistor ultra-high gain boost converter, specifically including the following steps:

[0042] S1. The reference value u of the output voltage of the common-ground dual-transistor ultra-high gain boost converter. o,ref With feedback value u o,f By comparing the results, the error signal e is obtained;

[0043] S2. The error signal e is sent to the PI controller, and after passing through the unidirectional limiting circuit, the modulation signal u is obtained. r ;

[0044] S3. Modulate the signal u r Each is respectively with the first unipolar triangular carrier u c1 Second unipolar triangular carrier u c2 After the cutoff, the drive signal u of the first switch S1 is obtained. gs,S1 The drive signal u of the second switch S2 gs,S2 The first unipolar triangular carrier u c1 With the second unipolar triangular carrier u c2 The amplitude of all are U cm The frequency is the same as f s The phases are 180° apart.

[0045] In one specific embodiment of the present invention, a voltage boosting device for a balcony photovoltaic interface is provided, the voltage boosting device comprising:

[0046] The aforementioned common-ground dual-tube ultra-high gain boost converter; the input terminal of the boost device is connected to a photovoltaic module, which is a single or multiple modules connected in parallel, and its maximum power point voltage range is 20~50V; the output terminal of the boost device is connected to a single-phase grid-connected inverter, and the rated AC output voltage of the inverter is 230V.

[0047] The following is about Figure 1 The working process of the common-ground dual-tube ultra-high gain boost converter shown is explained.

[0048] To simplify the analysis, the following assumptions are made: the switching transistor, energy storage element, diode, and inductor are all ideal devices; the intermediate capacitor C... int First capacitor C1, output filter capacitor C o Large enough to negligible voltage ripple; first input inductance L in1 Second input inductor L in2 The currents in the first inductor L1 and the second inductor L2 are continuous; the output filter capacitor C o The negative terminal is connected to the source terminals of the first switch S1 and the second switch S2 at a zero potential reference point.

[0049] Based on the above assumptions, Figure 1 The operation of the common-ground dual-transistor ultra-high gain boost converter is explained. The steady-state operation of the proposed common-ground dual-transistor ultra-high gain boost converter within one switching cycle can be divided into four modes. Its main equivalent circuit is as follows: Figures 3 to 5 As shown, the waveform is as follows Figure 6 As shown.

[0050] Mode 1, t0~t1 stage: (equivalent circuit as follows) Figure 3 (As shown)

[0051] At time t0, both the first switch S1 and the second switch S2 are turned on. The first phase diode D... ph1 With the second phase diode D ph2 When the diode is turned on, all other diodes are turned off, and the intermediate capacitor C... int The discharge occurs through two circuits formed by the first inductor L1, the first switch S1, and the second inductor L2, and the second switch S2, with the output filter capacitor C... o Discharge provides energy to the output. The first input inductor L... in1 With the second input inductor L in2 Withstand positive voltage U in The first inductor L1 and the second inductor L2 are subjected to a positive voltage U. Cint Therefore, the first input inductor current i Lin1 Second input inductor current i Lin2 First inductor current i L1 Second inductor current i L2 The numbers increase linearly. At this point, we have:

[0052] (1)

[0053] In the formula, L in1 L is the inductance of the first input inductor. in2 L1 is the inductance of the second input inductor, L2 is the inductance of the first inductor, and U is the inductance of the second inductor. Cint For the intermediate capacitor C int The average voltage.

[0054] At time t1, mode 1 ends.

[0055] Mode 2, t1~t2 stage: (equivalent circuit as follows) Figure 4 (As shown)

[0056] At time t1, the second switch S2 is turned off. At this time, the first phase diode D... ph1 Second input diode D in2 The second diode D2 is turned on; the first input inductor L in1 The first inductor L1 maintains its original rate of change and increases linearly, while the second input inductor L... in2 Withstand negative voltage U in -U Cint The second inductor L2 withstands a negative voltage U. Cint +U C1 -U Co Therefore, the current i Lin2 and i L2 It begins to decrease linearly. At this point, we have:

[0057] (2)

[0058] In the formula, U C1 U is the average voltage across the first capacitor C1. o This is the output voltage.

[0059] At time t2, mode 2 ends.

[0060] Mode 3, t2~t3 stage: (equivalent circuit as follows) Figure 3 (As shown)

[0061] The working principle and equivalent circuit of this mode are the same as those of mode 1, so they will not be described again here.

[0062] Mode 4, t3~t4 stage: (equivalent circuit as follows) Figure 5 (As shown)

[0063] At time t3, the first switch S1 is turned off, and the first input diode D... in1 Second phase diode D ph2 The first diode D1 is turned on; the second input inductor current i Lin2 With the second inductor current i L2 The original conversion rate continues to increase; the first input inductor L in1 Withstand negative voltage U in -U Cint The first inductor L1 withstands a negative voltage U. Cint -U C1 Therefore, the first input inductor current i Lin1 With the first inductor current i L1 It begins to decrease linearly. At this point, we have:

[0064] (3)

[0065] At time t4, mode 4 ends.

[0066] Based on the above working principle, the steady-state characteristics of the common-ground dual-tube ultra-high gain boost converter proposed in this invention will be analyzed below.

[0067] Ignoring dead time, based on the first input inductance L in1 Second input inductor L in2 Combining the volt-second balance of the first inductor L1 and the second inductor L2 with equations (1) to (3), we can obtain:

[0068] (4)

[0069] In the formula, T s The switching cycle.

[0070] According to equations (3) and (4), the voltage gain of the common-ground dual-transistor ultra-high gain boost converter proposed in this invention can be obtained as follows:

[0071] (5)

[0072] Furthermore, based on modal analysis, the voltage stress of the first switch S1 and the second switch S2, and the voltage stress of the first input diode D in the common-ground dual-transistor ultra-high gain boost converter proposed in this invention are also analyzed. in1 Second input diode D in2 First phase diode D ph1 Second phase diode D ph2 Voltage stress of the first diode D1 and the second diode D2, and the first capacitor C1 and the intermediate capacitor C. int Output filter capacitor C o The voltage stresses are respectively:

[0073] (6)

[0074] In the formula, U S1 For the voltage stress of the first switching transistor S1, U S2 For the voltage stress of the second switch S2, U Din1 The first input diode D in1 Voltage stress, U Din2 For the second input diode D in2 Voltage stress, U Dph1 The first phase diode D ph1 Voltage stress, U Dph2 For the second phase diode D ph2 Voltage stress, U D1 For the voltage stress of the first diode D1, U D2 For the voltage stress of the second diode D2, U C1 For the voltage stress of the first capacitor C1, U Cint For the intermediate capacitor C int Voltage stress, U Co For the output filter capacitor C o Voltage stress.

[0075] Based on the average current equivalent circuit, the average current stress of the common-ground dual-transistor ultra-high gain boost converter proposed in this invention can be obtained as follows:

[0076] (7)

[0077] In the formula, I S1 For the current stress of the first switching transistor S1, I S2 For the current stress of the second switch S2, I Din1 The first input diode D in1 Current stress, I Din2 For the second input diode D in2Current stress, I Dph1 The first phase diode D ph1 Current stress, I Dph2 For the second phase diode D ph2 Current stress, I D1 For the current stress of the first diode D1, I D2 For the current stress of the second diode D2, I Lin1 The first input inductor L in1 Current stress, I Lin2 For the second input inductor L in2 Current stress, I L1 For the current stress of the first inductor L1, I L2 For the current stress of the second inductor L2, I in This is the input current.

[0078] First input inductor L in1 With the second input inductor L in2 The average current stress is:

[0079] (8)

[0080] The average current stress of the first inductor L1 and the second inductor L2 is:

[0081] (9)

[0082] From equation (1), we can obtain the first input inductance L. in1 With the second input inductor L in2 The inductance of each is L in If the minimum input voltage U is required in,min If the peak-to-peak value of the inductor current does not exceed 40% of the maximum average inductor current, then the following condition must be met:

[0083] (10)

[0084] From equation (10), we can obtain the inductance L. in satisfy:

[0085] (11)

[0086] From equation (1), we can see that the inductance of both the first inductor L1 and the second inductor L2 is L. If the minimum input voltage U is required... in,min If the peak-to-peak value of the inductor current does not exceed 40% of the maximum average inductor current, then the following condition must be met:

[0087] (12)

[0088] From equation (12), the inductance L satisfies:

[0089] (13)

[0090] In this invention, the first input inductor L in1 Second input inductor L in2 The inductance values ​​of the first inductor L1 and the second inductor L2 are equal, and the voltage stress and current stress of the power transistors are equal. Therefore, similar devices can be used interchangeably, which is convenient for mass production.

[0091] To verify the correctness of the above theoretical analysis, a Saber simulation model was built to simulate and verify the common-ground dual-transistor ultra-high gain boost converter proposed in this invention. The simulation model parameters are as follows: input voltage U in =20V, output voltage U o =400V, maximum output power P o,max =1kW, switching frequency f s =50kHz. Furthermore, the first input inductor L in1 Second input inductor L in2 Both are 30μH; the first inductor L1 and the second inductor L2 are both 280μH; the intermediate capacitor C int The first capacitor C1 is 10μF, and the output filter capacitor C is 10μF. o It is 10μF.

[0092] Figure 7 The figure shows the input voltage u. in Output voltage u o and the first input inductor current i Lin1 Second input inductor current i Lin2 and the first inductor current i L1 Second inductor current i L2 The simulated waveform shows that when the duty cycle D≈0.684 and the input voltage U... in At 20V, the average output voltage U of the common-ground dual-transistor ultra-high gain boost converter proposed in this invention is... o =398.6V, measured voltage gain is U o / U in =398.6 / 20≈19.9, which is close to the theoretical value G=2 / (1-D). 2 ≈20 is basically consistent.

[0093] Figure 8 The current i of the first switch S1 is given in the figure. S1 and voltage u S1 The current i of the second switch S2 S2 and voltage u S2 The simulated waveform.

[0094] Figure 9 The first input diode D is given. in1 voltage u Din1 Second input diode D in2 voltage u Din2 First phase diode D ph1 voltage u Dph1 Second phase diode D ph2 voltage u Dph2 The voltage u of the first diode D1 D1 The voltage u of the second diode D2 D2 The simulation waveform shows that the first input diode D... in1 Second input diode D in2 The voltage stresses are basically equal, approximately equal to the output voltage U. o of Times, first phase diode D ph1 Second phase diode D ph2 The voltage stresses are basically equal, approximately equal to the output voltage U. o of The voltage stress of the first diode D1 is approximately times that of the output voltage U. o The voltage stress of the second diode D2 is approximately the output voltage. The values ​​were all roughly consistent with the theoretical values.

[0095] Figure 10 The intermediate capacitor C is given. int voltage u Cint The voltage u of the first capacitor C1 C1 Output filter capacitor C o voltage u Co The simulated waveform shows that the intermediate capacitor C... int The voltage stress is approximately equal to the output voltage U. o of The voltage stress on the first capacitor C1 is approximately times that of the output voltage U. o of Times, output filter capacitor C o The voltage stress is approximately equal to the output voltage U. o All values ​​are basically consistent with the theoretical values.

[0096] The simulation results above show that the common-ground dual-transistor ultra-high gain boost converter and control method proposed in this invention have the following advantages:

[0097] (1) The common-ground dual-tube ultra-high gain boost converter proposed in this invention achieves a balance between ultra-high gain and medium duty cycle, that is, ultra-high gain can be achieved under medium duty cycle, avoiding the efficiency reduction and stability problems caused by the extreme duty cycle required by traditional high gain converters.

[0098] (2) The common-ground dual-transistor ultra-high gain boost converter proposed in this invention has fewer switching transistors. At the same time, it has low voltage and current stress, can use low-voltage devices, effectively reduce cost and loss, and improve system efficiency.

[0099] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0100] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, and is not intended to limit it. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A common-ground dual-transistor ultra-high gain boost converter, characterized in that, The common-ground dual-transistor ultra-high gain boost converter includes a first input inductor L. in1 Second input inductor L in2 First input diode D in1 Second input diode D in2 First phase diode D ph1 Second phase diode D ph2 Intermediate capacitor C int First inductor L1, second inductor L2, first diode D1, second diode D2, first switch S1, second switch S2, first capacitor C1, output filter capacitor C o ; The first input inductor L in1 The first terminal and the second input inductor L in2 The first terminal is connected as the positive terminal of the input terminal of the common-ground dual-tube ultra-high gain boost converter; The intermediate capacitor C int The negative terminal is connected to the source of the first switch S1, the second switch S2, and the output filter capacitor C. o The negative terminal is connected to serve as the negative terminal of both the input and output terminals of the common-ground dual-transistor ultra-high gain boost converter. The first input inductor L in1 The second terminal is connected to the first input diode D in1 First phase diode D ph1 Anode connection; The second input inductor L in2 The second terminal is connected to the second input diode D in2 Second phase diode D ph2 Anode connection; The first input diode D in1 The cathode is connected to the first terminal of the first inductor L1, the first terminal of the second inductor L2, and the second input diode D. in2 Cathode, intermediate capacitor C int The positive terminal connection; The first phase diode D ph1 The cathode is connected to the second terminal of the first inductor L1, the anode of the first diode D1, and the drain of the first switching transistor S1; The second phase diode D ph2 The cathode is connected to the second terminal of the second inductor L2, the negative terminal of the first capacitor C1, and the drain of the second switch S2. The cathode of the first diode D1 is connected to the positive terminal of the first capacitor C1 and the anode of the second diode D2; The cathode of the second diode D2 and the output filter capacitor C o The positive terminal is connected to the ground and serves as the positive terminal of the output of the common-ground dual-tube ultra-high gain boost converter.

2. The common-ground dual-transistor ultra-high gain boost converter according to claim 1, characterized in that, The first input inductor L in1 With the second input inductor L in2 The inductance values ​​are all L in And satisfy: ； The inductance values ​​of the first inductor L1 and the second inductor L2 are both L, and they satisfy: ； In the formula, U in,min Indicates the minimum input voltage; U o Indicates the output voltage; D max This indicates the duty cycle of the switching transistor at the lowest input voltage; f s Indicates the switching frequency; P o,max This indicates the maximum output power.

3. The common-ground dual-transistor ultra-high gain boost converter according to claim 1, characterized in that, The ideal voltage gain G of the common-ground dual-transistor ultra-high gain boost converter is: ； In the formula, U in This represents the average value of the input voltage.

4. A control method for a common-ground dual-transistor ultra-high gain boost converter as described in any one of claims 1-3, characterized in that, The control method includes the following steps: S1. The reference value u of the output voltage of the common-ground dual-transistor ultra-high gain boost converter. o,ref With feedback value u o,f By comparing the results, the error signal e is obtained; S2. The error signal e is sent to the PI controller, and after passing through the unidirectional limiting circuit, the modulation signal u is obtained. r ; S3. Modulate the signal u r Each is respectively with the first unipolar triangular carrier u c1 Second unipolar triangular carrier u c2 After the cutoff, the drive signal u of the first switch S1 is obtained. gs,S1 The drive signal u of the second switch S2 gs,S2 The first unipolar triangular carrier u c1 With the second unipolar triangular carrier u c2 The amplitude of all are U cm The frequency is the same as f s The phases are 180° apart.

5. The application of the common-ground dual-tube ultra-high gain boost converter as described in any one of claims 1-3 in a balcony photovoltaic interface scenario.

6. A voltage boosting device for a balcony photovoltaic interface, characterized in that, The boost device is the common-ground dual-tube ultra-high gain boost converter as described in any one of claims 1-3; The input terminal of the boost device is connected to the photovoltaic module; The output of the boost device is connected to a single-phase grid-connected inverter.

7. The booster device according to claim 6, characterized in that, The photovoltaic modules are in the form of single or multiple modules connected in parallel, and their maximum power point voltage range is 20~50V; The rated AC output voltage of the single-phase grid-connected inverter is 230V.

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