Photovoltaic optimizer and system

Abstract

The invention discloses a photovoltaic optimizer and system. The photovoltaic optimizer comprises a first buck conversion circuit, a boost conversion circuit, a half-bridge driving chip, a half-bridge topology circuit and a second buck conversion circuit. The first buck conversion circuit is connected to a photovoltaic input voltage and is used for reducing the photovoltaic input voltage to a first buck voltage and inputting the first buck voltage to the boost conversion circuit. The step-up conversion circuit is used for boosting the first step-down voltage, outputting a first step-up voltage and a second step-up voltage to the half-bridge driving chip, and outputting a third step-up voltage to the second step-down conversion circuit; the half-bridge driving chip is used for outputting two paths of driving signals according to the first boosted voltage and the second boosted voltage to control the half-bridge topology circuit to output a constant-current power supply; the second buck conversion circuit is used for converting the third boost voltage into a second buck voltage to supply power to the auxiliary power supply. According to the invention, the working voltage range of the photovoltaic optimizer is improved, and the photovoltaic optimizer can be started and work stably under the condition of extremely low voltage and current.

Description

Technical Field

[0001] The invention relates to the field of solar photovoltaic technology, and in particular to a photovoltaic optimizer and system. Background Art

[0002] A photovoltaic optimizer is a device used by a photovoltaic power generation system to optimize the output power of photovoltaic modules to ensure that the output power of the photovoltaic power generation system is maximized.

[0003] The photovoltaic optimizer can only start when the photovoltaic input voltage (PV) is higher than the half-bridge drive operating voltage. For example, the half-bridge drive voltage is 10V, and the minimum starting voltage of the upper bridge arm is 12V. Therefore, the start-up voltage of the optimizer should be greater than 12V, and the voltage during normal operation should not be less than 16V. In addition, the photovoltaic optimizer can only work when the current input is large. When the current is weak, the photovoltaic input voltage changes greatly when the photovoltaic optimizer is working, and the photovoltaic input voltage often drops below the photovoltaic optimizer start-up voltage and stops working.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a photovoltaic optimizer and system to solve the problem that the operating voltage range of the existing photovoltaic optimizer is narrow and the photovoltaic input voltage will be lower than the starting voltage when the current is weak and stop working.

[0006] The technical solution of the present invention is as follows:

[0007] A photovoltaic optimizer, comprising: a first buck conversion circuit, a boost conversion circuit, a half-bridge driver chip, a half-bridge topology circuit and a second buck conversion circuit; wherein:

[0008] The first step-down conversion circuit is connected to the photovoltaic input voltage and is connected to the boost conversion circuit, and is used to step down the photovoltaic input voltage to a first step-down voltage and input it to the boost conversion circuit; wherein the first step-down voltage is greater than the minimum operating voltage of the boost conversion circuit;

[0009] The boost conversion circuit is also connected to the half-bridge drive chip and the second buck conversion circuit respectively, and is used to boost the first buck voltage and output a first boost voltage and a second boost voltage to the half-bridge drive chip, and output a third boost voltage to the second buck conversion circuit;

[0010] The half-bridge driving chip is connected to the half-bridge topology circuit, and is used to output two driving signals according to the first boost voltage and the second boost voltage to control the half-bridge topology circuit to output a constant current power supply;

[0011] The second step-down conversion circuit is also connected to the auxiliary power supply, and is used to convert the third boosted voltage into a second step-down voltage to supply power to the auxiliary power supply.

[0012] According to a further configuration of the present invention, the photovoltaic optimizer also includes: a control module, which is respectively connected to the second buck conversion circuit and the half-bridge driver chip, for detecting changes in the photovoltaic input voltage and for controlling the half-bridge driver chip to achieve constant current output.

[0013] According to a further configuration of the present invention, the half-bridge topology circuit comprises: an upper bridge arm MOS transistor, a lower bridge arm MOS transistor and an LC filter circuit; wherein,

[0014] The control end of the upper bridge arm MOS tube is connected to the first output end of the half-bridge driver chip, and the output end of the upper bridge arm MOS tube is connected to the LC filter circuit;

[0015] The control end of the lower bridge arm MOS tube is connected to the second output end of the half-bridge driving chip, and the output end of the lower bridge arm MOS tube is connected to the LC filtering circuit.

[0016] In a further configuration of the present invention, the power supply end of the half-bridge driving circuit is connected to the first boost voltage, and the first output end of the half-bridge driving chip outputs an upper bridge arm driving signal to drive the upper bridge arm MOS tube to work; the isolation voltage input end of the half-bridge driving chip is connected to the second boost voltage, and the lower bridge arm of the half-bridge driving chip outputs a lower bridge arm driving signal to drive the lower bridge arm MOS tube to work;

[0017] The first boost voltage is a non-isolated boost voltage, and the second boost voltage is an isolated boost voltage.

[0018] According to a further configuration of the present invention, the boost conversion circuit comprises: a boost unit and an isolation voltage output unit; wherein,

[0019] The boost unit is connected to the first buck conversion circuit, and is used for boosting the first buck voltage and outputting a first boost voltage to the half-bridge drive chip;

[0020] The isolated voltage output unit is connected to the first buck conversion circuit, and is used for boosting the first buck voltage and outputting a second boost voltage to the half-bridge drive chip.

[0021] According to a further configuration of the present invention, the boost unit comprises: a first resistor, a boost chip, a second resistor, a third resistor, a first diode, a first capacitor and a second capacitor; wherein,

[0022] One end of the first resistor is connected to the first step-down conversion circuit, and the other end of the first resistor is connected to the enable end of the boost chip;

[0023] The switch end of the boost chip is connected to the anode of the first diode;

[0024] One end of the second resistor is connected to the cathode of the first diode and the power supply end of the half-bridge driver chip respectively, and the other end of the second resistor is connected to one end of the third resistor;

[0025] The other end of the third resistor is grounded;

[0026] A common terminal of the second resistor and the third resistor is connected to a feedback terminal of the boost chip;

[0027] The first capacitor is connected in parallel with the second resistor and the third resistor;

[0028] The second capacitor is connected in parallel with the first capacitor.

[0029] According to a further configuration of the present invention, the isolated voltage output unit includes: a mutual inductor, a second diode, a third capacitor and a fourth capacitor; wherein,

[0030] A first pin of the input end of the mutual inductor is connected to the first step-down conversion circuit, a second pin of the input end of the mutual inductor is connected to the switch end of the boost chip, a first pin of the output end of the mutual inductor is connected to one end of the third capacitor, and a second pin of the output end of the mutual inductor is connected to the anode of the second diode;

[0031] The cathode of the second diode is connected to the other end of the third capacitor;

[0032] The fourth capacitor is connected in parallel with the third capacitor.

[0033] In a further configuration of the present invention, the photovoltaic optimizer further includes: a PLC communication circuit and a PLC loading circuit; wherein,

[0034] The PLC loading circuit is connected between the PLC communication circuit and the half-bridge topology circuit;

[0035] The PLC communication circuit is also connected to the control module and the boost conversion circuit, and is used to control the operating state of the photovoltaic optimizer according to the feedback signal of the control module and the PLC loading circuit.

[0036] According to a further configuration of the present invention, the photovoltaic optimizer further includes: an optimized output circuit, wherein the optimized output circuit is connected to the output end of the half-bridge topology circuit and is used to filter out the ripple of the constant current power supply output by the half-bridge topology circuit.

[0037] Based on the same inventive concept, the present invention also provides a photovoltaic optimization system, which includes a photovoltaic panel assembly, an inverter and the photovoltaic optimizer as described above; the photovoltaic optimizer is connected between the photovoltaic panel assembly and the inverter.

[0038] The present invention provides a photovoltaic optimizer and system, the photovoltaic optimizer includes: a first buck conversion circuit, a boost conversion circuit, a half-bridge driver chip, a half-bridge topology circuit and a second buck conversion circuit. The first buck conversion circuit is connected to the photovoltaic input voltage and connected to the boost conversion circuit, and is used to buck the photovoltaic input voltage to a first buck voltage and input it to the boost conversion circuit; wherein the first buck voltage is greater than the minimum operating voltage of the boost conversion circuit; the boost conversion circuit is also connected to the half-bridge driver chip and the second buck conversion circuit respectively, and is used to boost the first buck voltage and output the first boost voltage and the second boost voltage to the half-bridge driver chip, and output the third boost voltage to the second buck conversion circuit; the half-bridge driver chip is connected to the half-bridge topology circuit, and is used to output two drive signals according to the first boost voltage and the second boost voltage to control the half-bridge topology circuit to output a constant current power supply; the second buck conversion circuit is also connected to the auxiliary power supply, and is used to convert the third boost voltage into a second buck voltage to power the auxiliary power supply. The present invention reduces the photovoltaic input voltage to the minimum operating voltage (first step-down voltage) of the boost conversion circuit through a first step-down conversion circuit, and then obtains the half-bridge driver chip driving voltage (first step-up voltage and second step-up voltage) after being boosted by the boost conversion circuit, thereby improving the operating voltage range of the photovoltaic optimizer, so that the half-bridge driver chip can be stable within the operating voltage range, and the photovoltaic optimizer can be started and stably operate under extremely low voltage and current conditions, thereby improving the working performance of the photovoltaic optimizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary personnel in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0040] Figure 1 It is a principle block diagram of the photovoltaic optimizer in the present invention.

[0041] Figure 2 It is a circuit schematic diagram of a boost conversion circuit in one embodiment of the present invention.

[0042] Figure 3 It is a circuit schematic diagram of a board bridge driver chip in one embodiment of the present invention.

[0043] Marks in the accompanying drawings: 100, first step-down conversion circuit; 200, step-up conversion circuit; 210, step-up unit; 220, isolated voltage output unit; 300, half-bridge driver chip; 400, half-bridge topology circuit; 410, upper bridge arm MOS tube; 420, lower bridge arm MOS tube; 430, LC filter circuit; 500, second step-down conversion circuit; 600, control module; 700, PLC communication circuit; 800, PLC loading circuit; 900, optimized output circuit. DETAILED DESCRIPTION

[0044] The present invention provides a photovoltaic optimizer and system. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] In the embodiments and the scope of the patent application, unless the text specifically defines the article, "a", "an", "the" and "the" may also include plural forms. If there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0046] It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intermediate elements. In addition, the "connection" or "coupling" used herein can include wireless connection or wireless coupling. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0047] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0048] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0049] Please also see Figures 1 to 3 , the present invention provides a preferred embodiment of a photovoltaic optimizer.

[0050] The present invention provides a photovoltaic optimizer, such as Figure 1 As shown, it includes: a first buck conversion circuit 100 , a boost conversion circuit 200 , a half-bridge driving chip 300 , a half-bridge topology circuit 400 and a second buck conversion circuit 500 . The first buck conversion circuit 100 is connected to the photovoltaic input voltage and connected to the boost conversion circuit 200, and is used to step down the photovoltaic input voltage to a first step-down voltage and input it to the boost conversion circuit 200; wherein the first step-down voltage is greater than the minimum operating voltage of the boost conversion circuit 200; the boost conversion circuit 200 is also connected to the half-bridge driver chip 300 and the second buck conversion circuit 500 respectively, and is used to boost the first step-down voltage and output the first boost voltage and the second boost voltage to the half-bridge driver chip 300, and output the third boost voltage to the second buck conversion circuit 500; the half-bridge driver chip 300 is connected to the half-bridge topology circuit 400, and is used to output two drive signals according to the first boost voltage and the second boost voltage to control the half-bridge topology circuit 400 to output a constant current power supply; the second buck conversion circuit 500 is also connected to the auxiliary power supply, and is used to convert the third boost voltage into a second step-down voltage to power the auxiliary power supply.

[0051] In the above technical solution, the photovoltaic optimizer is connected to the photovoltaic panel assembly, and the voltage output by the photovoltaic panel assembly is the photovoltaic input voltage PV, and the photovoltaic input voltage is less than 100V. The auxiliary power supply includes the boost conversion circuit 200 and the subsequent circuit of the second buck conversion circuit 500. The minimum operating voltage of the boost conversion circuit 200 refers to the minimum driving voltage that the boost conversion circuit can perform boosting work, which is generally 2V, that is, the first buck voltage is greater than 2V.

[0052] In specific implementation, the first buck conversion circuit 100 is connected to the photovoltaic input voltage PV, and the photovoltaic input voltage is stepped down by the first buck conversion circuit 100 to output a first buck voltage greater than 2V to drive the boost conversion circuit 200 to work. The boost conversion circuit 200 outputs three boost voltage drives, wherein the first boost voltage and the second boost voltage are used to drive the half-bridge driver chip 300 to work, and the half-bridge driver chip 300 outputs an upper bridge arm drive signal and a lower bridge arm drive signal to drive the half-bridge topology circuit 400 to achieve constant current output, and the constant current is input to the inverter to achieve the power supply function. The third boosted voltage is used to drive the second buck conversion circuit 500 to work. The second buck conversion circuit 500 steps down the third boosted voltage to the second step-down voltage to supply power to various modules of the auxiliary power supply at the subsequent stage. In this way, the power supply voltage of each module of the auxiliary power supply is first boosted by the boost conversion circuit 200, and then stepped down by the second step-down conversion circuit 500 for conversion, so that the amplitude of the voltage conversion range can be greatly improved.

[0053] Therefore, the present invention reduces the photovoltaic input voltage to the minimum operating voltage (first step-down voltage) of the boost conversion circuit 200 through the first step-down conversion circuit 100, and then obtains the driving voltage (first step-up voltage and second step-up voltage) of the half-bridge driver chip 300 after being stepped up by the boost conversion circuit 200, thereby improving the operating voltage range of the photovoltaic optimizer. In other words, the photovoltaic optimizer can work normally when the photovoltaic input voltage is not less than 2V, so that the half-bridge driver chip 300 can be stable within the operating voltage range, and the photovoltaic optimizer can be started and work stably under extremely low voltage and current conditions. As long as the input-output power difference is greater than the consumption of the auxiliary circuit, it can be started normally, thereby avoiding the problem that the photovoltaic optimizer stops working when the photovoltaic input voltage is lower than the starting voltage when the current is weak, and improving the working performance of the photovoltaic optimizer.

[0054] In summary, the present invention improves the power generation efficiency of the photovoltaic optimizer, adapts to a relatively large voltage and current transformation range, and can optimize the photovoltaic power supply regardless of low voltage or low current, thereby greatly improving the power generation efficiency of the photovoltaic panel assembly.

[0055] Taking the driving voltage of the half-bridge driver chip 300 as 12V and the output voltage of the first buck conversion circuit 100 as 3.3V as an example, the first buck voltage is set at 3.3V so that the first buck conversion circuit 100 can still have a normal 3.3V voltage output when the photovoltaic input voltage is lower than 5V. Due to the change in the intensity of sunlight and the large change in the photovoltaic input voltage when the photovoltaic optimizer adjusts the current, the photovoltaic input voltage will drop below 3.3V instantly. When the photovoltaic input voltage jumps to below 5V, the first buck conversion circuit 100 will output a follow-up voltage slightly lower than 0.7V, so that the photovoltaic optimizer will not stop working due to power failure. When the first buck voltage is greater than 2V, the boost conversion circuit 200 can work normally, output a 12V first boost voltage of a non-isolated boost voltage to power the half-bridge driver chip 300, and output a 12V second boost voltage of an isolated boost voltage to drive the half-bridge driver chip 300 to output two drive signals. The boost conversion circuit 200 also outputs a third boost voltage (third boost voltage) which is supplied to each module of the subsequent auxiliary power supply after passing through the second buck conversion circuit 500, and can provide a stable power supply for each module of the subsequent auxiliary power supply. Therefore, as long as the input voltage of the boost conversion circuit 200 is not less than 2V, the subsequent circuit module of the boost conversion circuit 200 can be stabilized at the set voltage value, and is no longer affected by the high and low changes of the photovoltaic input voltage, ensuring that the photovoltaic optimizer can work stably.

[0056] In the above embodiment, when performing low current and low voltage tests, when the photovoltaic input voltage of the photovoltaic optimizer is 45V, the input current is 200mA, and the output current is 10A, the photovoltaic optimizer enters the current regulation mode, and then gradually lowers the photovoltaic input voltage until there is an output current at 5V, and the output current depends on the size of the input current.

[0057] In some embodiments, the operating voltage of the half-bridge driver chip 300 is 8-12V. When the input voltage of the boost converter circuit 200 is not less than 2V, the half-bridge driver chip 300 required to operate at a minimum operating voltage of 8V can also operate at a 12V voltage state, thereby increasing the operating voltage range of the photovoltaic optimizer.

[0058] It should be noted that because the power generation of each photovoltaic panel component is equivalent and there is no deviation, the output current is consistent. When the light and power of each photovoltaic panel component are normal, the current of the entire output loop is consistent. When a photovoltaic panel component is insufficient in power due to external reasons, the photovoltaic optimizer connected to it will enter the current regulation mode. At this time, the photovoltaic optimizer works in the direct mode, that is, to reduce the output voltage, keep the loop current consistent, and ensure the maximum power of the entire inverter system.

[0059] For example, 20 photovoltaic panels are connected in series to supply power to an inverter. When the sky is clear at noon, the current of the entire series circuit reaches 15A. Due to objective reasons, each photovoltaic panel is blocked or aged, causing the power generation efficiency of the photovoltaic panel to decrease. At this time, the photovoltaic optimizer changes from the direct mode to the current regulation mode, and adjusts its own current output according to the current of the entire series circuit until the entire circuit current reaches 15A. Even if the output voltage is reduced, the current of the entire circuit can be maintained unchanged, ensuring the maximum output power.

[0060] In some embodiments, Figure 1 As shown, the photovoltaic optimizer also includes: a control module 600, which is respectively connected to the second buck conversion circuit 500 and the half-bridge driver chip 300, for detecting changes in the photovoltaic input voltage and for controlling the half-bridge driver chip 300 to achieve constant current output.

[0061] In this embodiment, the control module 600 is a micro control unit, and the half-bridge driver chip 300 has a power supply terminal VDD, an isolated voltage input terminal (HB, HS), a first input terminal HI, a second input terminal LI, a first output terminal HO and a second output terminal LO. The power supply terminal VDD is used to connect to a first boost voltage V2, and the first boost voltage V2 is a non-isolated boost voltage, which provides power for the lower bridge arm of the half-bridge driver chip 300. The isolated voltage input terminal is connected to the second boost voltage V3, and the second boost voltage V3 is an isolated boost voltage, which provides power for the upper bridge arm of the half-bridge driver chip 300. The first output terminal HO is used to output an upper bridge arm drive signal, and the second output terminal LO is used to output a lower bridge arm drive signal. The first input terminal HI and the second input terminal LI are respectively connected to the micro control unit, and the micro control unit can control the half-bridge driver chip 300 to alternately output an upper bridge arm drive signal and a lower bridge arm signal.

[0062] In some embodiments, Figure 1 and Figure 3 As shown, the half-bridge topology circuit 400 includes: an upper bridge arm MOS transistor 410, a lower bridge arm MOS transistor 420 and an LC filter circuit 430. The control end of the upper bridge arm MOS transistor 410 is connected to the first output end HO of the half-bridge driver chip 300, and the output end of the upper bridge arm MOS transistor 410 is connected to the LC filter circuit 430; the control end of the lower bridge arm MOS transistor 420 is connected to the second output end LO of the half-bridge driver chip 300, and the output end of the lower bridge arm MOS transistor 420 is connected to the LC filter circuit 430.

[0063] In this embodiment, the upper bridge arm MOS transistor 410 is connected to the first output terminal HO of the half-bridge driver chip 300, and the upper bridge arm MOS transistor 410 is turned on according to the upper bridge arm driving signal, and the lower bridge arm MOS transistor 420 is connected to the second output terminal LO of the half-bridge driver chip 300, and the lower bridge arm MOS transistor 420 is turned on according to the lower bridge arm driving signal. The micro control unit controls the upper bridge arm MOS transistor 410 and the lower bridge arm MOS transistor 420 to work alternately by outputting a PWM signal and controls the charging and discharging of the LC filter circuit 430 by adjusting the duty cycle to achieve constant current output.

[0064] In some embodiments, Figure 1 As shown, the boost conversion circuit 200 includes: a boost unit 210 and an isolated voltage output unit 220. The boost unit 210 is connected to the first buck conversion circuit 100, and is used to boost the first buck voltage V1 and output a first boost voltage to the half-bridge driver chip 300; the isolated voltage output unit 220 is connected to the first buck conversion circuit 100, and is used to boost the first buck voltage V1 and output a second boost voltage to the half-bridge driver chip 300.

[0065] In this embodiment, the boost unit 210 and the isolated voltage output unit 220 are respectively connected to the first buck conversion circuit 100, and can respectively boost the first buck voltage V1 output by the first buck conversion circuit 100, and respectively output a non-isolated first boost voltage and an isolated second boost voltage to drive the half-bridge driver chip 300 to work.

[0066] In some embodiments, Figures 1 to 3 As shown, the boost unit 210 includes: a first resistor R1, a boost chip U1, a second resistor R2, a third resistor R3, a first diode D1, a first capacitor C1 and a second capacitor C2. Among them, one end of the first resistor R1 is connected to the first buck conversion circuit 100, and the other end of the first resistor R1 is connected to the enable end of the boost chip U1; the switch end of the boost chip U1 is connected to the anode of the first diode D1; one end of the second resistor R2 is respectively connected to the cathode of the first diode D1 and the power supply end VDD of the half-bridge driver chip 300, and the other end of the second resistor R2 is connected to one end of the third resistor R3; the other end of the third resistor R3 is grounded; the common end of the second resistor R2 and the third resistor R3 is connected to the feedback end FB of the boost chip U2; the first capacitor C1 is connected in parallel with the second resistor R2 and the third resistor R3; the second capacitor C2 is connected in parallel with the first capacitor C1.

[0067] In this embodiment, the first resistor R1 is a clamping resistor, the second resistor R2 is connected in series with the third resistor R3, the first resistor R1 is connected to the first step-down voltage V1 to the enable terminal EN of the boost chip U2, and the boost chip U2 boosts the output voltage (first boost voltage) to a set voltage according to the resistance values ​​of the second resistor R2 and the third resistor R3, wherein the magnitude of the first boost voltage can be adjusted according to the resistance values ​​of the second resistor R2 and the third resistor R3. The first diode D is a Schottky diode, which can prevent current from flowing back to the boost chip, and the first capacitor C1 and the second capacitor C2 are filter capacitors.

[0068] In some embodiments, Figures 1 to 3 As shown, the isolated voltage output unit 220 includes: a mutual inductor L1, a second diode D2, a third capacitor C3 and a fourth capacitor C4. Among them, the first pin 1 of the input end of the mutual inductor L1 is connected to the first step-down conversion circuit 100, the second pin 2 of the input end of the mutual inductor L1 is connected to the switch end SW of the boost chip U2, the first pin 3 of the output end of the mutual inductor L1 is connected to one end of the third capacitor C3, the second pin 4 of the output end of the mutual inductor L1 is connected to the anode of the second diode D2; the cathode of the second diode D2 is connected to the other end of the third capacitor C3; the fourth capacitor C4 is connected in parallel with the third capacitor C3.

[0069] In this embodiment, the mutual inductor L1 is composed of a group of copper core coils added to one side of the inductor, as an isolation transformer. The second diode D2 is a rectifier diode, and the third capacitor C3 and the fourth capacitor C4 are filter capacitors. The first step-down voltage V1 output by the mutual inductor L1 connected to the first step-down conversion circuit 100 is isolated and boosted by the mutual inductor L1 to obtain the second boost voltage (isolated boost voltage) and then output through the second diode D2. Its working principle is: according to the working principle of the BOOST circuit, the constantly changing current in the primary coil of the mutual inductor L1 will induce a constantly changing current in the secondary coil, and the secondary coil output is rectified and filtered by the second diode D2 and the third capacitor C3 and the fourth capacitor C4 to output a DC voltage. It should be noted that the magnitude of the second boost voltage can be adjusted according to the turns ratio of the primary and secondary coils of the mutual inductor L1. For example, after adjusting the turns ratio of the primary coil and the secondary coil of the mutual inductor, the output voltage can be 12V.

[0070] In some embodiments, Figure 1As shown, the photovoltaic optimizer also includes: a PLC communication circuit 700 and a PLC loading circuit 800. The PLC loading circuit 800 is connected between the PLC communication circuit 700 and the half-bridge topology circuit 400; the PLC communication circuit 700 is also connected to the control module 600 and the boost conversion circuit 200, and is used to control the operating state of the photovoltaic optimizer according to the feedback signal of the control module 600 and the PLC loading circuit 800.

[0071] In this embodiment, the PLC loading circuit 800 is connected between the LC filter circuit 430 and the PLC communication circuit 700, and can transmit PLC signals. The PLC communication circuit 700 is also connected to the micro control unit and the boost circuit, and can be connected to the fourth output voltage output by the boost conversion circuit 200 for power supply, and can communicate with the micro control unit, and realize background monitoring of the photovoltaic optimizer according to the PLC signal fed back by the PLC loading circuit 800 to control the operating state of the photovoltaic optimizer.

[0072] In some embodiments, Figure 1 As shown, the photovoltaic optimizer also includes: an optimized output circuit 900, which is connected to the output end of the half-bridge topology circuit 400, and can filter out the ripple of the constant current power supply output by the half-bridge topology circuit 400, so as to obtain a more stable DC voltage.

[0073] In some embodiments, the present invention further provides a photovoltaic optimization system, which includes a photovoltaic panel assembly, an inverter, and a photovoltaic optimizer as described above. The photovoltaic optimizer is connected between the photovoltaic panel assembly and the inverter, and the photovoltaic optimizer operates at the photovoltaic input voltage output by the photovoltaic panel assembly. When the photovoltaic optimizer is in current regulation mode, the entire reflux can be maintained unchanged to ensure maximum output power. The photovoltaic optimizer is specifically described in an embodiment of a photovoltaic optimizer, and will not be repeated here.

[0074] In summary, the photovoltaic optimizer and system provided by the present invention have the following beneficial effects:

[0075] The present invention improves the power generation efficiency of the photovoltaic optimizer, is suitable for a relatively large voltage and current transformation range, and can optimize the photovoltaic power source in both a low voltage state and a relatively small current state, thereby greatly improving the power generation efficiency of the photovoltaic panel assembly;

[0076] The power supply voltage of each module of the auxiliary power supply is first boosted by a boost conversion circuit, and then converted by a second buck conversion circuit after being stepped down. The amplitude of the voltage conversion range can be greatly improved, and the post-stage circuit module of the boost conversion circuit can be stabilized at the set voltage value, ensuring that the photovoltaic optimizer can work stably.

[0077] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A photovoltaic optimizer, characterized in that: include: A first buck conversion circuit, a boost conversion circuit, a half-bridge driver chip, a half-bridge topology circuit and a second buck conversion circuit; wherein, The first step-down conversion circuit is connected to the photovoltaic input voltage and is connected to the boost conversion circuit, and is used to step down the photovoltaic input voltage to a first step-down voltage and input it to the boost conversion circuit; wherein the first step-down voltage is greater than the minimum operating voltage of the boost conversion circuit; The boost conversion circuit is also connected to the half-bridge drive chip and the second buck conversion circuit respectively, and is used to boost the first buck voltage and output a first boost voltage and a second boost voltage to the half-bridge drive chip, and output a third boost voltage to the second buck conversion circuit; The half-bridge driving chip is connected to the half-bridge topology circuit, and is used to output two driving signals according to the first boost voltage and the second boost voltage to control the half-bridge topology circuit to output a constant current power supply; The second step-down conversion circuit is also connected to the auxiliary power supply, and is used to convert the third boosted voltage into a second step-down voltage to supply power to the auxiliary power supply.

2. The photovoltaic optimizer according to claim 1, characterized in that: Also includes: A control module, the control module is respectively connected to the second buck conversion circuit and the half-bridge driver chip, and is used to detect changes in the photovoltaic input voltage and to control the half-bridge driver chip to achieve constant current output.

3. The photovoltaic optimizer according to claim 2, characterized in that: The half-bridge topology circuit includes: an upper bridge arm MOS tube, a lower bridge arm MOS tube and an LC filter circuit; wherein, The control end of the upper bridge arm MOS tube is connected to the first output end of the half-bridge driver chip, and the output end of the upper bridge arm MOS tube is connected to the LC filter circuit; The control end of the lower bridge arm MOS tube is connected to the second output end of the half-bridge driving chip, and the output end of the lower bridge arm MOS tube is connected to the LC filtering circuit.

4. The photovoltaic optimizer according to claim 3, characterized in that: The power supply end of the half-bridge driving circuit is connected to the first boost voltage, and the first output end of the half-bridge driving chip outputs an upper bridge arm driving signal to drive the upper bridge arm MOS tube to work; the isolation voltage input end of the half-bridge driving chip is connected to the second boost voltage, and the lower bridge arm of the half-bridge driving chip outputs a lower bridge arm driving signal to drive the lower bridge arm MOS tube to work; The first boost voltage is a non-isolated boost voltage, and the second boost voltage is an isolated boost voltage.

5. The photovoltaic optimizer according to claim 1, characterized in that: The boost conversion circuit comprises: a boost unit and an isolation voltage output unit; wherein, The boost unit is connected to the first buck conversion circuit, and is used for boosting the first buck voltage and outputting a first boost voltage to the half-bridge drive chip; The isolated voltage output unit is connected to the first buck conversion circuit, and is used for boosting the first buck voltage and outputting a second boost voltage to the half-bridge drive chip.

6. The photovoltaic optimizer according to claim 5, characterized in that: The boost unit includes: a first resistor, a boost chip, a second resistor, a third resistor, a first diode, a first capacitor and a second capacitor; wherein, One end of the first resistor is connected to the first step-down conversion circuit, and the other end of the first resistor is connected to the enable end of the boost chip; The switch end of the boost chip is connected to the anode of the first diode; One end of the second resistor is connected to the cathode of the first diode and the power supply end of the half-bridge driver chip respectively, and the other end of the second resistor is connected to one end of the third resistor; The other end of the third resistor is grounded; A common terminal of the second resistor and the third resistor is connected to a feedback terminal of the boost chip; The first capacitor is connected in parallel with the second resistor and the third resistor; The second capacitor is connected in parallel with the first capacitor.

7. The photovoltaic optimizer according to claim 6, characterized in that: The isolated voltage output unit includes: a mutual inductor, a second diode, a third capacitor and a fourth capacitor; wherein, A first pin of the input end of the mutual inductor is connected to the first step-down conversion circuit, a second pin of the input end of the mutual inductor is connected to the switch end of the boost chip, a first pin of the output end of the mutual inductor is connected to one end of the third capacitor, and a second pin of the output end of the mutual inductor is connected to the anode of the second diode; The cathode of the second diode is connected to the other end of the third capacitor; The fourth capacitor is connected in parallel with the third capacitor.

8. The photovoltaic optimizer according to claim 2, characterized in that: Also includes: PLC communication circuit and PLC loading circuit; among them, The PLC loading circuit is connected between the PLC communication circuit and the half-bridge topology circuit; The PLC communication circuit is also connected to the control module and the boost conversion circuit, and is used to control the operating state of the photovoltaic optimizer according to the feedback signal of the control module and the PLC loading circuit.

9. The photovoltaic optimizer according to claim 1, characterized in that: Also includes: An optimized output circuit is connected to the output end of the half-bridge topology circuit and is used to filter out the ripple of the constant current power supply output by the half-bridge topology circuit.

10. A photovoltaic optimization system, characterized in that: It comprises a photovoltaic panel assembly, an inverter and a photovoltaic optimizer as claimed in any one of claims 1 to 9; the photovoltaic optimizer is connected between the photovoltaic panel assembly and the inverter.

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