An efficient control system and method based on four-segment linear zero-delay blind-zone converter

Abstract

The present invention relates to an efficient control system and method based on a four-segment linear zero-delay converter without blind spots, including a photovoltaic power generation system, a DC-DC converter, a lithium battery, and a high-voltage difference current limiter, a constant-voltage difference current limiter, a first-segment zero-delay linear converter, a second-segment zero-delay linear converter, a third-segment zero-delay linear converter, and a fourth-segment zero-delay linear converter. The present invention uses a four-segment linear zero-delay converter without blind spots to linearly convert input and output voltages, further eliminate sampling blind spots and control delays, and improve energy collection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a high-efficiency control system and method based on a four-segment linear zero-delay blind-zone-free converter. Background Art

[0002] As human resource consumption increases and non-renewable resources on the earth decrease, the world is looking for new alternative energy sources for humans. As a renewable energy source, solar energy has great room for development. However, photovoltaic cells themselves have the problem of low energy conversion efficiency. It is necessary to consider both high-intensity charging when there is sufficient sunlight and current-limited charging when the light is weak.

[0003] The photovoltaic power generation system is mainly composed of photovoltaic solar panels, lithium batteries and charging controllers. The entire system can achieve maximum control of the output power of solar photovoltaic cells; when there is sufficient sunlight, the energy of the solar photovoltaic panels can be transferred to the lithium battery for storage to the maximum extent. When the light is insufficient, the charging control voltage is automatically adjusted to achieve optimal efficiency charging on the premise of ensuring charging efficiency. The charging controller generally uses a BUCK type DC-DC converter to convert the photovoltaic cell voltage to the charging voltage to ensure voltage conversion efficiency. Summary of the invention

[0004] In view of this, the purpose of the present invention is to propose an efficient control system and method based on a four-segment linear zero-delay blind-spot-free converter, which uses a four-segment linear zero-delay blind-spot-free converter to linearly convert the input and output voltages respectively, further eliminating sampling blind spots and control delays, thereby improving energy collection efficiency.

[0005] The present invention is implemented by the following scheme: an efficient control system based on a four-segment linear zero-delay non-blind-zone converter, including a photovoltaic power generation system, a DC-DC converter, a lithium battery, and also including a high-voltage difference current limiter, a constant-voltage difference current limiter, a first-segment zero-delay linear converter, a second-segment zero-delay linear converter, a third-segment zero-delay linear converter, and a fourth-segment zero-delay linear converter;

[0006] The output end of the photovoltaic power generation system is respectively connected to the input end of the DC-DC converter and the input end of the first section of the zero-delay linear converter. The output end of the DC-DC converter is connected to the power supply port of the lithium battery via a high-voltage difference current limiter and a constant-voltage difference current limiter in sequence; the output end of the first section of the zero-delay linear converter is connected to the input end of the second section of the zero-delay linear converter; the first input end of the third section of the zero-delay linear converter is connected to the power supply port of the lithium battery, and the second input end is connected to the output end of the second section of the zero-delay linear converter, and the output end of the third section of the zero-delay linear converter is connected to the input end of the fourth section of the zero-delay linear converter; the output end of the fourth section of the zero-delay linear converter is connected to the feedback voltage control pin FB of the DC-DC converter.

[0007] Furthermore, the first section zero-delay linear converter includes a first resistor R1, a second resistor R2 and a third resistor R3; one end of the first resistor R1 is connected to the output end of the photovoltaic power generation system as the input end of the first section zero-delay linear converter, the other end of the first resistor is respectively connected to one end of the second resistor R2 and one end of the third resistor R3, the other end of the second resistor R2 is grounded, and the other end of the third resistor R3 is used as the output end of the first section zero-delay linear converter.

[0008] Further, the second-section zero-delay linear converter includes a first operational amplifier, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7; one end of the sixth resistor R6 serves as the input end of the second-section zero-delay linear converter, and the other end of the sixth resistor R6 is respectively connected to the negative input end of the first operational amplifier and one end of the seventh resistor R7; the other end of the seventh resistor R7 is connected to the output end of the first operational amplifier and serves as the output end of the second-section zero-delay linear converter; one end of the fourth resistor R4 is respectively connected to one end of the fifth resistor R5 and the positive input end of the first operational amplifier, the other end of the fourth resistor R4 is grounded, and the other end of the fifth resistor R5 is connected to the VCC end of the first operational amplifier and connected to VCC.

[0009] Further, the third-segment zero-delay linear converter includes a second operational amplifier, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12 and a thirteenth resistor R13; one end of the eighth resistor R8 serves as a first input end of the third-segment zero-delay linear converter, and the other end of the eighth resistor R8 is respectively connected to one end of the ninth resistor R9 and a negative input end of the second operational amplifier; the other end of the ninth resistor R9 is connected to an output end of the second operational amplifier and serves as an output end of the third-segment zero-delay linear converter; one end of the twelfth resistor R12 serves as a second input end of the third-segment zero-delay linear converter, the other end of the twelfth resistor R12 is connected to one end of the thirteenth resistor R13, and the other end of the thirteenth resistor R13 is respectively connected to one end of the eleventh resistor R11, one end of the tenth resistor R10 and a positive input end of the second operational amplifier; the other end of the eleventh resistor R11 is connected to the Vcc end of the second operational amplifier and to VCC; the other end of the tenth resistor R10 is grounded.

[0010] Furthermore, the fourth section zero-delay linear converter includes a fourteenth resistor R14, a fifteenth resistor R15 and a sixteenth resistor R16; one end of the fourteenth resistor R14 serves as an input end of the fourth section zero-delay linear converter, the other end of the fourteenth resistor R14 is respectively connected to one end of the fifteenth resistor R15 and one end of the sixteenth resistor R16, the other end of the fifteenth resistor R15 is grounded, and the other end of the sixteenth resistor R16 serves as an output end of the fourth section zero-delay linear converter.

[0011] Furthermore, the high-voltage difference current limiter includes a seventeenth resistor R17, an eighteenth resistor R18 and an NMOS tube, one end of the seventeenth resistor R17 is connected to the source of the NMOS tube and serves as the input end of the high-voltage difference current limiter, the other end of the seventeenth resistor R17 is respectively connected to one end of the eighteenth resistor R18 and the gate of the NMOS tube, the other end of the eighteenth resistor R18 is grounded, and the drain of the NMOS tube serves as the output end of the high-voltage difference current limiter.

[0012] Furthermore, the constant voltage difference current limiter includes a nineteenth resistor R19 and a twentieth resistor R20, one end of the nineteenth resistor R19 serves as an input end of the constant voltage difference current limiter, the other end of the nineteenth resistor R19 is connected to one end of the twentieth resistor R20, and the other end of the twentieth resistor R20 serves as an output end of the constant voltage difference current limiter.

[0013] The present invention also provides a method for a control system based on the above-mentioned four-stage linear zero-delay blind-zone converter for a photovoltaic power generation system, which uses a zero-delay linear converter to sample from the output end of the photovoltaic power generation system and the power supply port of the lithium battery respectively, and the sampled output voltage of the photovoltaic power generation system undergoes four linear changes, and is combined with the power supply voltage of the lithium battery to obtain an optimal control voltage, and the optimal control voltage is used to control the feedback voltage pin FB of the DC-DC converter, thereby adjusting the output voltage of the DC-DC converter so that the output voltage of the DC-DC converter maintains an optimal voltage difference with the lithium battery voltage to control the charging current.

[0014] Furthermore, the optimal control voltage V FB The output voltage of the photovoltaic power generation system V solar 、Lithium battery voltage V bat The relationship is a binary linear combination, that is:

[0015] V FB =k1×V solar +k2×V bat +b;

[0016] Among them, k1 and k2 are constants, which are determined by the parameters of the four-stage zero-delay linear converter.

[0017] Furthermore, the high-voltage differential current limiter and the constant-voltage differential current limiter are used to perform current limiting control respectively; when the lithium battery voltage is lower than a preset value, the DC-DC converter outputs a minimum constant operating voltage, at which time there is a large voltage difference between the output voltage of the DC-DC converter and the battery voltage, and the high-voltage differential current limiter takes effect; as the lithium battery voltage increases, the output voltage of the DC-DC converter increases accordingly, and maintains a relatively low voltage difference, and the constant-voltage differential current limiter takes effect.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the present invention can use four linear converters to perform voltage conversion on the basis of maintaining the differential pressure stability between the DC-DC output voltage and the lithium battery voltage and providing charging power at the maximum photovoltaic power, so as to achieve zero-delay and blind-zone real-time control. Compared with the traditional MPPT control scheme, it reduces the energy loss from sampling judgment to control output delay and the energy loss caused by inaccurate control due to the minimum sampling resolution during the voltage sampling process. The present invention can significantly improve the efficiency of the entire photovoltaic power generation system, and can realize the photovoltaic power generation system to continuously charge the lithium battery on continuous rainy days when the current is so weak that it can only output 100uA, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 4 is a system principle block diagram of an embodiment of the present invention.

[0020] Figure 2Schematic diagram of the first section zero-delay linear converter circuit in an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the second section zero-delay linear converter circuit in an embodiment of the present invention.

[0022] Figure 4 Schematic diagram of the third section zero-delay linear converter circuit in an embodiment of the present invention.

[0023] Figure 5 Schematic diagram of the fourth section zero-delay linear converter circuit in an embodiment of the present invention.

[0024] Figure 6 Schematic diagram of a constant voltage difference current limiter and a constant voltage difference current limiter circuit according to an embodiment of the present invention.

[0025] Figure 7 Schematic diagram of the output voltage and feedback voltage circuit of the DC-DC converter in an embodiment of the present invention.

[0026] Figure 8 Schematic diagram of the difference between the energy collection of the method of the embodiment of the present invention and the traditional MPPT control method or the MCU sampling analysis and calculation method. In the figure, (a) is the energy collection of the traditional MPPT control method or the MCU sampling analysis and calculation method, and (b) is the energy collection of the method of the embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] like Figure 1As shown, this embodiment provides an efficient control system based on a four-segment linear zero-delay converter without blind spots, including a photovoltaic power generation system, a DC-DC converter (a BUCK type DC-DC converter may be used), a lithium battery, and also includes a high-voltage difference current limiter, a constant-voltage difference current limiter, a first-segment zero-delay linear converter, a second-segment zero-delay linear converter, a third-segment zero-delay linear converter, and a fourth-segment zero-delay linear converter;

[0031] The output end of the photovoltaic power generation system is respectively connected to the input end of the DC-DC converter and the input end of the first section of the zero-delay linear converter. The output end of the DC-DC converter is connected to the power supply port of the lithium battery via a high-voltage difference current limiter and a constant-voltage difference current limiter in sequence; the output end of the first section of the zero-delay linear converter is connected to the input end of the second section of the zero-delay linear converter; the first input end of the third section of the zero-delay linear converter is connected to the power supply port of the lithium battery, and the second input end is connected to the output end of the second section of the zero-delay linear converter, and the output end of the third section of the zero-delay linear converter is connected to the input end of the fourth section of the zero-delay linear converter; the output end of the fourth section of the zero-delay linear converter is connected to the feedback voltage control pin FB of the DC-DC converter.

[0032] like Figure 2 As shown, in this embodiment, the first section zero-delay linear converter includes a first resistor R1, a second resistor R2 and a third resistor R3; one end of the first resistor R1 is connected to the output end of the photovoltaic power generation system as the input end of the first section zero-delay linear converter, the other end of the first resistor is respectively connected to one end of the second resistor R2 and one end of the third resistor R3, the other end of the second resistor R2 is grounded, and the other end of the third resistor R3 is used as the output end of the first section zero-delay linear converter.

[0033] The first section of the zero-delay linear converter uses the voltage value of the solar photovoltaic power generation system as input and uses a star topology resistor bridge for linear conversion, ensuring that the entire sampling process has zero delay and no blind spots, while achieving the function of obtaining the voltage value from the solar photovoltaic system. At the same time, it ensures that the relationship between the topology output and input is a zero-delay linear conversion without blind spots. The input-output voltage relationship of the first section of the zero-delay linear converter is as follows:

[0034] V C1O =k 11 ×V SOLAR +b1;

[0035] In the formula, b1=-I I01 *R3, where I I01is the leakage current of the negative input terminal of the first operational amplifier, which is a constant and is provided by the chip datasheet. Generally, the resistance value of R3 is much larger than that of R1 and R2.

[0036] like Figure 3 As shown, in this embodiment, the second-segment zero-delay linear converter includes a first operational amplifier, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7; one end of the sixth resistor R6 serves as the input end of the second-segment zero-delay linear converter, and the other end of the sixth resistor R6 is respectively connected to the negative input end of the first operational amplifier and one end of the seventh resistor R7; the other end of the seventh resistor R7 is connected to the output end of the first operational amplifier and serves as the output end of the second-segment zero-delay linear converter; one end of the fourth resistor R4 is respectively connected to one end of the fifth resistor R5 and the positive input end of the first operational amplifier, the other end of the fourth resistor R4 is grounded, and the other end of the fifth resistor R5 is connected to the VCC end of the first operational amplifier and connected to VCC.

[0037] The second section of zero-delay linear converter converts the output value V through the voltage of the solar photovoltaic power generation system C1O As input, the first operational amplifier is used for linear transformation to ensure that the entire sampling process has zero delay and no blind spot, while realizing the output value V after voltage conversion of the solar photovoltaic power generation system C1O To fine-tune the control voltage V C2O The linear transformation of the output and the use of the operational amplifier to rail saturation voltage characteristics to achieve input voltage overvoltage and undervoltage protection functions. Taking a 10V solar panel as an example, the transformation is as follows:

[0038]

[0039] In the formula, The value of VCC is 3.3V. In the above formula, V solaar That is, the output voltage of the photovoltaic power generation system, that is, Figure 1 V in , through the first section of zero-delay linear converter, V solaar With V C1O When the solar panel output voltage is higher than 4.5V and lower than 10V, the op amp output voltage is proportional to V C1O The charging current is automatically adjusted according to the light intensity. When the solar panel output voltage is lower than 4.5V, the op amp output voltage clock remains unchanged at 0V (lowest rail voltage), and the charging current is no longer adjusted to ensure the stability of the solar panel output voltage. When the solar panel output voltage is higher than 10V, the op amp output voltage clock remains unchanged at VCC (highest rail voltage), and the charging current is no longer adjusted to ensure the stability of the solar panel output current.

[0040] like Figure 4 As shown, in this embodiment, the third section zero-delay linear converter includes a second operational amplifier, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12 and a thirteenth resistor R13; one end of the eighth resistor R8 serves as a first input end of the third section zero-delay linear converter, and the other end of the eighth resistor R8 is respectively connected to one end of the ninth resistor R9 and the negative input end of the second operational amplifier; the other end of the ninth resistor R9 is connected to the output end of the second operational amplifier and serves as the output end of the third section zero-delay linear converter; one end of the twelfth resistor R12 serves as a second input end of the third section zero-delay linear converter, and the other end of the twelfth resistor R12 is connected to one end of the thirteenth resistor R13, and the other end of the thirteenth resistor R13 is respectively connected to one end of the eleventh resistor R11, one end of the tenth resistor R10 and the positive input end of the second operational amplifier; the other end of the eleventh resistor R11 is connected to the Vcc end of the second operational amplifier and to VCC; the other end of the tenth resistor R10 is grounded.

[0041] The third section of zero-delay linear converter converts the lithium battery simulated voltage value V BAT As input, the output rail voltage limiting characteristic of the op amp is used to realize that when the lithium battery voltage is higher than the set threshold value, the output control voltage no longer changes, thereby controlling the output voltage of the fourth section zero-delay linear converter to control the DC-DC output voltage. When the lithium battery voltage is higher than the set threshold value, constant voltage charging is performed, and when the lithium battery voltage is lower than the threshold value, constant current charging is performed to achieve lithium battery charging protection. The input and output characteristics of the third section zero-delay linear converter are as follows:

[0042]

[0043] In the formula, k 33 =-R9 / R8, b3 = (1+R9 / R8)*V 2- , V 2- =V 2+ ,in, VCC=3.3V.

[0044] like Figure 5 As shown, in this embodiment, the fourth section zero-delay linear converter includes a fourteenth resistor R14, a fifteenth resistor R15 and a sixteenth resistor R16; one end of the fourteenth resistor R14 serves as the input end of the fourth section zero-delay linear converter, the other end of the fourteenth resistor R14 is respectively connected to one end of the fifteenth resistor R15 and one end of the sixteenth resistor R16, the other end of the fifteenth resistor R15 is grounded, and the other end of the sixteenth resistor R16 serves as the output end of the fourth section zero-delay linear converter.

[0045] The fourth section zero-delay linear converter receives the output of the third section linear conversion and uses the star topology resistor bridge for linear conversion, ensuring that the entire sampling process has zero delay and no blind spots, while achieving the function of obtaining the voltage value from the solar photovoltaic system, and at the same time ensuring that the relationship between the topology output and input is a zero-delay linear conversion without blind spots, as shown in the following formula, where V C4O (V BF ) is the total output of the four-stage conversion, which is used to control the feedback voltage pin FB of the DC-DC:

[0046] V C4O =k 44 ×V C3O +b4;

[0047] In the formula, b4=I FB *R16, where I FB The leakage current of the DC-DC converter feedback pin FB input is a constant and is provided by the chip datasheet. In general, the resistance value of R16 is much larger than that of R14 and R15.

[0048] like Figure 6 As shown, in this embodiment, the high-voltage difference current limiter includes a seventeenth resistor R17, an eighteenth resistor R18 and an NMOS tube, one end of the seventeenth resistor R17 is connected to the source of the NMOS tube and serves as the input end of the high-voltage difference current limiter, the other end of the seventeenth resistor R17 is respectively connected to one end of the eighteenth resistor R18 and the gate of the NMOS tube, the other end of the eighteenth resistor R18 is grounded, and the drain of the NMOS tube serves as the output end of the high-voltage difference current limiter. The constant-voltage difference current limiter includes a nineteenth resistor R19 and a twentieth resistor R20, one end of the nineteenth resistor R19 serves as the input end of the constant-voltage difference current limiter, the other end of the nineteenth resistor R19 is connected to one end of the twentieth resistor R20, and the other end of the twentieth resistor R20 serves as the output end of the constant-voltage difference current limiter.

[0049] When the battery voltage is lower than the DC-DC converter output minimum voltage minus the maximum voltage difference that can be maintained in the constant current mode, the DC-DC converter outputs the minimum constant working voltage to maintain constant voltage charging. At this time, there is a large voltage difference between the output voltage of the DC-DC converter and the battery voltage, and the high-voltage difference current limiter works. Its working principle is to use the approximate linear working curve of the MOS tube in the low voltage section. As the battery voltage increases, the voltage of the DC-DC converter increases accordingly, and maintains a low voltage difference, and the constant voltage difference current limiter works. The high-voltage difference current limiter is used to work under the condition that the DC-DC converter outputs the minimum constant working voltage, and the volt-ampere characteristic curve of the MOS tube under low working voltage conditions is used to achieve current limiting. At the same time, when the DC-DC converter output voltage increases, due to the nonlinear characteristics of the MOS tube, the MOS tube can be turned on quickly and the impedance is extremely low. The high-voltage current limiter is equivalent to a path. At this time, the two-port pure resistance linear network of the constant voltage difference current limiter is used to achieve current limiting.

[0050] like Figure 7 As shown, in this embodiment, the output voltage V out With the feedback voltage V FB (V C40 ) is as follows:

[0051] V out =(V FB / R22+Is)*R21+V FB ;

[0052] Among them, Is is the current value of Vout offset after regulation, which is determined by V C30 Decide, and V C3O By V solar and V BAT Determined together (see the output characteristic formula of the zero-delay linear converter in the third paragraph),

[0053] This embodiment also provides a control system method based on the four-segment linear zero-delay no-blind-zone converter for photovoltaic power generation system described above, using a zero-delay linear converter to sample from the output end of the photovoltaic power generation system and the power supply port of the lithium battery respectively, and the sampled output voltage of the photovoltaic power generation system undergoes four linear changes, and combined with the power supply voltage of the lithium battery, to obtain the optimal control voltage, and use the optimal control voltage to control the feedback voltage pin FB of the DC-DC converter, and then adjust the output voltage of the DC-DC converter, so that the output voltage of the DC-DC converter and the lithium battery voltage maintain an optimal voltage difference to control the charging current. While ensuring that the photovoltaic power generation system charges the lithium battery with the highest efficiency, the charging current can maintain the difference between the output voltage of the DC-DC converter and the lithium battery voltage stable, thereby ensuring that the charging current remains stable.

[0054] In this embodiment, the optimal control voltage V FB The output voltage of the photovoltaic power generation system V solar 、Lithium battery voltage V bat The relationship is a binary linear combination, that is:

[0055] V FB =k1×V solar +k2×V bat +b;

[0056] Among them, k1 and k2 are constants, which are determined by the parameters of the four-stage zero-delay linear converter. The binary linear combination formula is obtained by substituting the output characteristic formula of the four-stage zero-delay linear converter into the DC-DC converter feedback voltage pin FB voltage V FB Through linear transformation control, the DC-DC output voltage can be adjusted within a certain range.

[0057] In this embodiment, the high-voltage differential current limiter and the constant-voltage differential current limiter are used to perform current limiting control respectively; when the lithium battery voltage is lower than a preset value, the DC-DC converter outputs a minimum constant operating voltage. At this time, there is a large voltage difference between the output voltage of the DC-DC converter and the battery voltage, and the high-voltage differential current limiter works; as the lithium battery voltage increases, the output voltage of the DC-DC converter increases accordingly, and maintains a lower voltage difference, and the constant-voltage differential current limiter works.

[0058] Preferably, the present embodiment utilizes the fourth section zero-delay linear converter to realize constant current and then constant voltage charging of the battery, and utilizes the first and second sections zero-delay linear converters to realize automatic adjustment of the charging current according to the light intensity to maintain a stable voltage difference. The fourth section zero-delay linear converter is utilized to realize voltage regulation of the feedback voltage control pin of the DC-DC. The linear characteristics of the MOS tube are utilized to realize high-voltage difference current limiting, and the nonlinear characteristics of the MOS tube and a two-port linear pure resistance network are utilized to realize low-voltage difference current limiting. The four independent zero-delay linear converters are all constructed with low-power linear analog operational amplifiers and star-shaped resistor bridge designs, which can realize blind-zone sampling over the entire voltage range, and zero delay in the feedback control process, eliminating energy loss caused by feedback delay. The difference between it and the traditional MPPT control method or energy collection using the MCU sampling analysis and calculation method is as follows: Figure 8 As shown, this embodiment can achieve normal charging of lithium batteries when the light intensity is as weak as 100uA output, and the energy collection efficiency is measured to be higher than 70%. Figure 8 As shown, the method of the present invention is much better than traditional solar energy collection schemes such as MPPT and sampling controller (about 19%).

[0059] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. An efficient control system based on a four-segment linear zero-delay non-blind-zone converter, comprising a photovoltaic power generation system, a DC-DC converter, and a lithium battery, characterized in that: It also includes a high-voltage differential current limiter, a constant-voltage differential current limiter, a first-stage zero-delay linear converter, a second-stage zero-delay linear converter, a third-stage zero-delay linear converter, and a fourth-stage zero-delay linear converter; The output end of the photovoltaic power generation system is respectively connected to the input end of the DC-DC converter and the input end of the first section of the zero-delay linear converter, and the output end of the DC-DC converter is connected to the power supply port of the lithium battery via a high-voltage differential current limiter and a constant-voltage differential current limiter in sequence; The output end of the first section zero-delay linear converter is connected to the input end of the second section zero-delay linear converter; the first input end of the third section zero-delay linear converter is connected to the power supply port of the lithium battery, and the second input end is connected to the output end of the second section zero-delay linear converter, and the output end of the third section zero-delay linear converter is connected to the input end of the fourth section zero-delay linear converter; the output end of the fourth section zero-delay linear converter is connected to the feedback voltage control pin FB of the DC-DC converter; The first section zero-delay linear converter comprises a first resistor R1, a second resistor R2 and a third resistor R3; one end of the first resistor R1 is connected to the output end of the photovoltaic power generation system as the input end of the first section zero-delay linear converter, the other end of the first resistor is respectively connected to one end of the second resistor R2 and one end of the third resistor R3, the other end of the second resistor R2 is grounded, and the other end of the third resistor R3 is used as the output end of the first section zero-delay linear converter; The second-segment zero-delay linear converter includes a first operational amplifier, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7; one end of the sixth resistor R6 serves as an input end of the second-segment zero-delay linear converter, and the other end of the sixth resistor R6 is respectively connected to the negative input end of the first operational amplifier and one end of the seventh resistor R7; the other end of the seventh resistor R7 is connected to the output end of the first operational amplifier and serves as the output end of the second-segment zero-delay linear converter; one end of the fourth resistor R4 is respectively connected to one end of the fifth resistor R5 and the positive input end of the first operational amplifier, the other end of the fourth resistor R4 is grounded, and the other end of the fifth resistor R5 is connected to the VCC end of the first operational amplifier and connected to VCC; The third section zero-delay linear converter includes a second operational amplifier, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12 and a thirteenth resistor R13; one end of the eighth resistor R8 serves as a first input end of the third section zero-delay linear converter, and the other end of the eighth resistor R8 is respectively connected to one end of the ninth resistor R9 and a negative input end of the second operational amplifier; the other end of the ninth resistor R9 is connected to an output end of the second operational amplifier and serves as an output end of the third section zero-delay linear converter; one end of the twelfth resistor R12 serves as a second input end of the third section zero-delay linear converter, the other end of the twelfth resistor R12 is connected to one end of the thirteenth resistor R13, and the other end of the thirteenth resistor R13 is respectively connected to one end of the eleventh resistor R11, one end of the tenth resistor R10 and a positive input end of the second operational amplifier; the other end of the eleventh resistor R11 is connected to the Vcc end of the second operational amplifier and to VCC; the other end of the tenth resistor R10 is grounded; The fourth section zero-delay linear converter includes a fourteenth resistor R14, a fifteenth resistor R15 and a sixteenth resistor R16; one end of the fourteenth resistor R14 serves as the input end of the fourth section zero-delay linear converter, the other end of the fourteenth resistor R14 is respectively connected to one end of the fifteenth resistor R15 and one end of the sixteenth resistor R16, the other end of the fifteenth resistor R15 is grounded, and the other end of the sixteenth resistor R16 serves as the output end of the fourth section zero-delay linear converter.

2. According to claim 1, a high-efficiency control system based on a four-segment linear zero-delay non-blind-zone converter is characterized in that: The high-voltage difference current limiter includes a seventeenth resistor R17, an eighteenth resistor R18 and an NMOS tube, one end of the seventeenth resistor R17 is connected to the source of the NMOS tube and serves as the input end of the high-voltage difference current limiter, the other end of the seventeenth resistor R17 is respectively connected to one end of the eighteenth resistor R18 and the gate of the NMOS tube, the other end of the eighteenth resistor R18 is grounded, and the drain of the NMOS tube serves as the output end of the high-voltage difference current limiter.

3. The high-efficiency control system based on a four-segment linear zero-delay non-blind-zone converter according to claim 1 is characterized in that: The constant voltage difference current limiter includes a nineteenth resistor R19 and a twentieth resistor R20, one end of the nineteenth resistor R19 serves as the input end of the constant voltage difference current limiter, the other end of the nineteenth resistor R19 is connected to one end of the twentieth resistor R20, and the other end of the twentieth resistor R20 serves as the output end of the constant voltage difference current limiter.

4. A method for an efficient control system based on a four-segment linear zero-delay non-blind-zone converter according to any one of claims 1 to 3, characterized in that: A zero-delay linear converter is used to sample the output end of the photovoltaic power generation system and the power supply port of the lithium battery respectively. The sampled output voltage of the photovoltaic power generation system undergoes four linear changes and is combined with the power supply voltage of the lithium battery to obtain the optimal control voltage. The optimal control voltage is used to control the feedback voltage pin FB of the DC-DC converter, and then the output voltage of the DC-DC converter is adjusted so that the output voltage of the DC-DC converter maintains an optimal voltage difference with the lithium battery voltage to control the charging current.

5. The method of a high-efficiency control system based on a four-segment linear zero-delay non-blind-zone converter according to claim 4 is characterized in that: Optimum control voltage V FB The output voltage of the photovoltaic power generation system V solar 、Lithium battery voltage V bat The relationship is a binary linear combination, that is: V FB =k1×V solar +k2×V bat +b; in, k 1 and k 2 is a constant determined by the parameters of the four-section zero-delay linear converter.

6. The method of a high-efficiency control system based on a four-segment linear zero-delay non-blind-zone converter according to claim 5, characterized in that: The high-voltage differential current limiter and the constant-voltage differential current limiter are used to perform current limiting control respectively; when the lithium battery voltage is lower than a preset value, the DC-DC converter outputs a minimum constant operating voltage. At this time, there is a large voltage difference between the output voltage of the DC-DC converter and the battery voltage, and the high-voltage differential current limiter takes effect; As the lithium battery voltage increases, the output voltage of the DC-DC converter increases accordingly and maintains a low voltage difference, and the constant voltage difference current limiter takes effect.

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