Voltage conversion circuit and photovoltaic optimizer

Abstract

The utility model discloses a voltage conversion circuit and a photovoltaic optimizer. The voltage conversion circuit comprises a voltage conversion module, a driving module, a power supply module and a switch module. The voltage conversion module comprises a first bridge arm and a second bridge arm; the driving module comprises a driving unit, an energy storage unit and a pull-down unit; the driving unit is connected with the control ends of the first bridge arm and the second bridge arm and the energy storage unit; the energy storage unit is connected with the first bridge arm; the power supply module is connected with the energy storage unit; the pull-down unit is connected between the first end of the switch module and the control end of the first bridge arm, and the second end of the switch module is connected with the second end of the first bridge arm; the switch module is configured to be switched off in a first state, and the power supply module is configured to be switched on in the first state and supplies power to the energy storage unit; the switch module is configured to be switched on in the second state, and the power supply module is configured to be switched on or switched off in the second state. According to the technical scheme of the utility model, the direct connection of the first bridge arm can be realized, and the power consumption of the photovoltaic optimizer is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of voltage conversion circuits, and particularly to a voltage conversion circuit and a photovoltaic optimizer. Background Art

[0002] With the development of new energy power generation technology, photovoltaic power generation applications are becoming more and more widespread. Photovoltaic modules can convert solar energy into electrical energy. When the photovoltaic modules are shaded, the output power of the photovoltaic modules is affected, thus affecting the power generation efficiency. A photovoltaic optimizer can enable the photovoltaic modules to achieve maximum power point tracking and ensure that each module outputs at the maximum power.

[0003] The photovoltaic optimizer includes a buck circuit, such as a BUCK buck circuit. The upper bridge arm of the BUCK buck circuit is powered by a bootstrap power supply method. That is, when the lower bridge arm of the BUCK buck circuit is turned on, it powers the bootstrap capacitor. After the lower bridge arm is turned off, the bootstrap capacitor discharges to power the upper bridge arm of the BUCK buck circuit. Therefore, the existing photovoltaic optimizer cannot keep the upper bridge arm of the BUCK buck circuit always on, and when the photovoltaic modules are not shaded, the power consumption of the BUCK buck circuit of the photovoltaic optimizer is relatively large, affecting the power generation amount of the photovoltaic system. Summary of the Utility Model

[0004] The utility model provides a voltage conversion circuit and a photovoltaic optimizer to solve the problems that the photovoltaic optimizer cannot keep the upper bridge arm of the buck circuit always on and has a relatively large power consumption when the photovoltaic modules are not shaded.

[0005] According to one aspect of the utility model, a voltage conversion circuit is provided, including:

[0006] A voltage conversion module, including a first bridge arm and a second bridge arm; the first end of the first bridge arm is connected to an input voltage, and the second bridge arm is connected to the second end of the first bridge arm; the voltage conversion module is configured to convert the input voltage to obtain an output voltage;

[0007] A driving module, including a driving unit, an energy storage unit, and a pull-down unit; the driving unit is respectively connected to the control ends of the first bridge arm and the second bridge arm, and the energy storage unit; the driving unit is configured to transmit a driving signal to the voltage conversion module; the energy storage unit is connected to the second end of the first bridge arm, and the energy storage unit is configured to supply power to the first bridge arm when discharging;

[0008] A power supply module and a switching module; the power supply module is connected to the energy storage unit; the pull-down unit is connected between the first end of the switching module and the control end of the first bridge arm, and the second end of the switching module is connected to the second end of the first bridge arm; the switching module is configured to be turned off in the first state, and the power supply module is configured to be turned on in the first state and supply power to the energy storage unit; the switching module is configured to be turned on in the second state, and the power supply module is configured to be turned on or off in the second state, so that the voltage conversion module converts the input voltage.

[0009] Optionally, the switching module includes an optocoupler;

[0010] The third end of the optocoupler accesses a first control signal, the fourth end of the optocoupler is grounded, the first end of the optocoupler is connected to the first end of the pull-down unit, and the second end of the optocoupler is connected to the second end of the first bridge arm; the optocoupler is configured to be turned on in response to the effective level of the first control signal.

[0011] Optionally, the power supply module includes a photovoltaic output optocoupler;

[0012] The third end of the photovoltaic output optocoupler accesses a second control signal, the fourth end of the photovoltaic output optocoupler is grounded, the first end of the photovoltaic output optocoupler is electrically connected to the first end of the energy storage unit, and the second end of the photovoltaic output optocoupler is electrically connected to the second end of the energy storage unit; the photovoltaic output optocoupler is configured to be turned on in response to the effective level of the second control signal to output a charging voltage to charge the energy storage unit.

[0013] Optionally, the voltage conversion circuit further includes: a power supply module;

[0014] The power supply module includes a power supply unit and a power inductor. The power supply unit accesses the input voltage, the power supply unit is connected to the first end of the power inductor, and the second end of the power inductor is connected to the power supply end of the driving unit;

[0015] The power supply module includes a voltage conversion unit, and the voltage conversion unit includes a first winding and a second winding. The first winding is the power inductor; the first end of the second winding is connected to the first end of the energy storage unit, and the second end of the second winding is connected to the second end of the energy storage unit.

[0016] Optionally, the voltage conversion unit further includes a first diode, a first capacitor and a zener diode;

[0017] The first end of the first diode is connected to the first end of the second winding, and the second end of the first diode is connected to the first end of the energy storage unit;

[0018] The first capacitor is connected between the first end and the second end of the energy storage unit;

[0019] The voltage stabilizing diode is connected between the first end and the second end of the energy storage unit.

[0020] Optionally, the pull-down unit includes a pull-down resistor;

[0021] The first end of the pull-down resistor is electrically connected to the first end of the switching module, and the second end of the pull-down resistor is electrically connected to the control end of the first arm.

[0022] Optionally, the driving module further includes a second diode and a third resistor;

[0023] The first end of the third resistor is electrically connected to the power supply module, the second end of the third resistor is electrically connected to the first end of the second diode, and the second end of the second diode is electrically connected to the first end of the energy storage unit.

[0024] Optionally, the energy storage unit includes an energy storage capacitor;

[0025] The first pole of the energy storage capacitor is electrically connected to the first bootstrap terminal of the driving unit, and the second pole of the energy storage capacitor is electrically connected to the second bootstrap terminal of the driving unit.

[0026] Optionally, the first arm includes at least one first transistor, and the second arm includes at least one second transistor;

[0027] The first pole of the first transistor is connected to the input voltage, the second pole of the first transistor is connected to the first pole of the second transistor, and the second pole of the second transistor is grounded.

[0028] According to another aspect of the present invention, a photovoltaic optimizer is provided, and the photovoltaic optimizer includes the voltage conversion circuit according to any embodiment of the present invention.

[0029] The technical solution of the embodiment of the present invention is that when the photovoltaic module is shaded, the switching module is turned on, the power supply module is turned on or off, and the voltage conversion module can perform voltage conversion normally to adjust the output power of the photovoltaic module and achieve maximum power point tracking. When the photovoltaic module is not shaded, the switching module is turned off, the power supply module is turned on, and the power supply module charges the energy storage unit, and the energy storage unit supplies power to the first arm. In this way, the second arm can be turned off to ensure that the first arm is always turned on. Moreover, when the switching module is turned off, the pull-down unit no longer consumes electric energy, reducing the power consumption, and thus ensuring the output power of the photovoltaic module.

[0030] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present utility model, nor is it used to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. Brief Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 is a schematic structural diagram of a voltage conversion circuit provided by an embodiment of the present utility model;

[0033] Figure 2 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present utility model;

[0034] Figure 3 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present utility model;

[0035] Figure 4 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present utility model;

[0036] Figure 5 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present utility model;

[0037] Figure 6 is a schematic structural diagram of a circuit of a photovoltaic optimizer provided by an embodiment of the present utility model. Detailed Embodiments

[0038] In order to enable those skilled in the art to better understand the solutions of the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only some, rather than all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the scope of protection of the present utility model.

[0039] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present utility model are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0040] Aiming at the problem that the upper bridge arm of the buck circuit cannot always conduct in the photovoltaic optimizer, and the power consumption of the photovoltaic optimizer is relatively large when the photovoltaic module is not shaded, this embodiment provides a voltage conversion circuit. The voltage conversion circuit can be applied to a photovoltaic optimizer.

[0041] Figure 1 It is a schematic structural diagram of a voltage conversion circuit provided by an embodiment of the present utility model. Refer to Figure 1 , the voltage conversion circuit includes:

[0042] A voltage conversion module 110, including a first bridge arm 111 and a second bridge arm 112; a first end of the first bridge arm 111 is connected to an input voltage Vpv, and the second bridge arm 112 is connected to a second end of the first bridge arm 111; the voltage conversion module 110 is configured to convert the input voltage Vpv to obtain an output voltage Vout;

[0043] A driving module 120, including a driving unit 121, an energy storage unit 122 and a pull-down unit 123; the driving unit 121 is respectively connected to the control ends of the first bridge arm 111 and the second bridge arm 112, and the energy storage unit 122; the driving unit 121 is configured to transmit a driving signal to the voltage conversion module 110; the energy storage unit 122 is connected to the second end of the first bridge arm 111, and the energy storage unit 122 is configured to supply power to the first bridge arm 111 when discharging;

[0044] A power supply module 130 and a switch module 140; the power supply module 130 is connected to the energy storage unit 122; the pull-down unit 123 is connected between the first end of the switch module 140 and the control end of the first bridge arm 111, and the second end of the switch module 140 is connected to the second end of the first bridge arm 111; the switch module 140 is configured to be turned off in the first state, and the power supply module 130 is configured to be turned on in the first state and supply power to the energy storage unit 122; the switch module 140 is configured to be turned on in the second state, and the power supply module 130 is configured to be turned on or off in the second state, so that the voltage conversion module 110 converts the input voltage Vpv.

[0045] Among them, the driving unit 121 is respectively connected to the control ends of the first bridge arm 111 and the second bridge arm 112, and can transmit driving signals to the control ends of the first bridge arm 111 and the second bridge arm 112. The driving unit 121 is respectively connected to the first end and the second end of the energy storage unit 122, and the second end of the energy storage unit 122 is connected to the second end of the first bridge arm 111, so that when the energy storage unit 122 discharges, it supplies power to the first bridge arm 111.

[0046] Among them, the power supply module 130 is respectively connected to the first end and the second end of the energy storage unit 122. The first end of the pull-down unit 123 is connected to the first end of the switch module 140, and the second end of the pull-down unit 123 is connected to the control end of the first bridge arm 111.

[0047] Among them, the input voltage Vpv is the voltage output by the photovoltaic module. The voltage conversion module 110 can convert the input voltage Vpv, which can be buck or boost, and this embodiment does not limit it. The voltage conversion module 110 can include a BUCK circuit or a Boost circuit, and the voltage conversion module 110 can also include a Buck-Boost circuit, and this embodiment does not limit it. The voltage conversion module 110 includes a first bridge arm 111 and a second bridge arm 112. The first bridge arm 111 can be the upper bridge arm, and the second bridge arm 112 can be the lower bridge arm. The first bridge arm 111 can include at least one transistor, and the second bridge arm 112 can include at least one transistor.

[0048] The driving module 120 can drive the conduction and turn-off of the first bridge arm 111 and control the conduction and turn-off of the second bridge arm 112. The driving unit 121 outputs driving signals to the first bridge arm 111 and the second bridge arm 112. For example, it transmits the first driving signal HO to the control end of the first bridge arm 111 and transmits the second driving signal LO to the control end of the second bridge arm 112. When the first driving signal HO is at an effective level, the first bridge arm 111 conducts, and when the first driving signal HO is at an invalid level, the first bridge arm 111 turns off. When the second driving signal LO is at an effective level, the second bridge arm 112 conducts, and when the second driving signal LO is at an invalid level, the second bridge arm 112 turns off. In this way, the conduction timing of the first bridge arm 111 and the second bridge arm 112 can be controlled by controlling the levels of the first driving signal HO and the second driving signal LO, and further the output voltage Vout of the voltage conversion module 110 can be controlled, so that the output voltage Vout meets the requirements of the load or the power grid, or meets the requirements of maximum power output. Among them, the effective level can be a high level and the invalid level is a low level; or the effective level is a low level and the invalid level is a high level, and this embodiment does not limit it.

[0049] Among them, the energy storage unit 122 can store energy, so that when the first bridge arm 111 is turned on, it supplies power to the first bridge arm 111. The power supply module 130 can output a voltage when it is turned on to charge the energy storage unit 122, facilitating the energy storage unit 122 to supply power to the first bridge arm 111. Thus, it is not necessary to supply power to the energy storage unit 122 when the second bridge arm 112 is turned on, so that the first bridge arm 111 can be controlled to remain turned on. When there is no need to step down or step up the voltage, the first bridge arm 111 is kept turned on, making the output voltage meet the requirements.

[0050] Specifically, the second state may be that the photovoltaic module is blocked, the dirt on the photovoltaic module accumulates, or the components are inconsistent, etc., that is, the second state is when the output power of the photovoltaic module needs to be optimized. By setting the switch module 140, when the photovoltaic module is blocked and the output power needs to be optimized, that is, when step-down or step-up is required, the switch module 140 is turned on and the power supply module 130 is turned off, then the energy storage unit 122 is charged when the second bridge arm 112 is turned on. The first end of the second bridge arm 112 is connected to the first end of the first bridge arm 111, and the second end of the second bridge arm 112 is grounded. When the second bridge arm 112 is turned on, the potential of the second end of the first bridge arm 111 is pulled down, that is, the potential of the second end of the energy storage unit 122 is pulled down. When the second bridge arm 112 is turned off and the first bridge arm 111 is turned on, the potential of the second end of the first bridge arm 111 rises, making the potential of the second end of the energy storage unit 122 rise. The charge stored in the energy storage unit 122 remains unchanged, and the potential of the first end of the energy storage unit 122 rises, then the potential of the first driving signal output by the driving unit 121 to the first bridge arm 111 rises, which can better drive the first bridge arm 111 to turn on, realizing the energy storage unit 122 supplying power to the first bridge arm 111. Or, when the switch module 140 is turned on, the power supply module 130 is also turned on to supply power to the energy storage unit 122, facilitating the energy storage unit 122 to supply power to the first bridge arm 111.

[0051] Moreover, when the switch module 140 is turned on, the first end and the second end of the switch module 140 are turned on, then a loop can be formed among the switch module 140, the pull-down unit 123, the first end of the first bridge arm 111, and the control end of the second bridge arm 112. The junction capacitance of the transistor in the first bridge arm 111 can be quickly released through the pull-down unit 123, which can improve the efficiency of the first bridge arm 111.

[0052] In this way, when the photovoltaic module is blocked, the switch module 140 is turned on and the power supply module 130 is turned off, and the voltage conversion module 110 can normally perform voltage conversion, realizing the adjustment of the output power of the photovoltaic module and achieving maximum power point tracking.

[0053] In the first state, that is, when the photovoltaic module is unobstructed and there is no need to optimize the output power, that is, there is no need to step up or step down the voltage, the switch module 140 is turned off, and the power supply module 130 is turned on. The power supply module 130 charges the energy storage unit 122, so that the potential of the first driving signal HO output from the driving unit 121 to the first bridge arm 111 is relatively high, which can better drive the first bridge arm 111 to conduct, realizing that the energy storage unit 122 supplies power to the first bridge arm 111. In this way, the second driving signal LO can be an invalid level, causing the second bridge arm 112 to turn off, realizing that the first bridge arm 111 is always conducting until the output power of the photovoltaic module needs to be optimized.

[0054] Moreover, when the switch module 140 is turned off, the switch module 140, the pull-down unit 123, the first end of the first bridge arm 111, and the control end of the second bridge arm 112 cannot form a loop, so the pull-down unit 123 no longer consumes electrical energy, reducing the power consumption, and thus the output power of the photovoltaic module can be guaranteed.

[0055] In the technical solution of this embodiment, when the photovoltaic module is blocked, the switch module is turned on, the power supply module is turned on or off, and the voltage conversion module can normally perform voltage conversion to adjust the output power of the photovoltaic module and achieve maximum power point tracking. When the photovoltaic module is unobstructed, the switch module is turned off, the power supply module is turned on, and the power supply module charges the energy storage unit. The energy storage unit supplies power to the first bridge arm. In this way, the second bridge arm can be turned off, realizing that the first bridge arm is always conducting. Moreover, when the switch module is turned off, the pull-down unit no longer consumes electrical energy, reducing the power consumption, and thus the output power of the photovoltaic module can be guaranteed.

[0056] Based on the above technical solution, Figure 2 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present invention. Optionally, referring to Figure 2 , the switch module 140 includes an optocoupler U1;

[0057] The third end of the optocoupler U1 is connected to the first control signal Dr1, the fourth end of the optocoupler U1 is grounded, the first end of the optocoupler U1 is connected to the first end of the pull-down unit 123, and the second end of the optocoupler U1 is connected to the second end of the first bridge arm 111; the optocoupler U1 is configured to conduct in response to the effective level of the first control signal Dr1.

[0058] Among them, the first control signal Dr1 can be sent by the control chip in the photovoltaic optimizer. When the photovoltaic module is shaded and the output power needs to be adjusted, the first control signal Dr1 is at an effective level, causing the optocoupler U1 to conduct; when the photovoltaic object is not shaded and the output power does not need to be adjusted, the first control signal Dr1 is at an invalid level, causing the optocoupler U1 to turn off. For example, if the third terminal of the optocoupler U1 is the anode of the light-emitting diode in the optocoupler U1, the effective level of the first control signal Dr1 is a high level.

[0059] In this way, when the photovoltaic module is not shaded, the optocoupler U1 is turned off, and the pull-down unit 123 no longer consumes electrical energy, which can reduce power consumption.

[0060] Optionally, refer to Figure 2 , the switch module 140 further includes a first resistor R1, and the third terminal of the optocoupler U1 is connected to the first control signal Dr1 through the first resistor R1. The first resistor R1 can limit the current to avoid a large current input to the optocoupler U1.

[0061] Based on the above technical solution, the possible circuit structure of the power supply module 130 will be described below, but it does not limit the present application.

[0062] In one implementation, optionally, refer to Figure 2 , the power supply module 130 includes a photovoltaic output optocoupler U2;

[0063] The third terminal of the photovoltaic output optocoupler U2 is connected to the second control signal Dr2, the fourth terminal of the photovoltaic output optocoupler U2 is grounded, the first terminal of the photovoltaic output optocoupler U2 is electrically connected to the first terminal of the energy storage unit 122, and the second terminal of the photovoltaic output optocoupler U2 is electrically connected to the second terminal of the energy storage unit 122; the photovoltaic output optocoupler U2 is configured to conduct in response to the effective level of the second control signal Dr2 to output a charging voltage to charge the energy storage unit 122.

[0064] Specifically, the photovoltaic output optocoupler U2, i.e., the photovoltaic output photoelectric coupler, can convert light into voltage output. When the photovoltaic module is unobstructed and there is no need to optimize the output power, that is, there is no need for step-up or step-down, the switch module 140 responds to the first control signal Dr1 to turn off, and the photovoltaic output optocoupler U2 responds to the second control signal Dr2 to turn on. The photovoltaic output optocoupler U2 outputs a voltage to charge the energy storage unit 122, so that the potential of the first drive signal HO output by the drive unit 121 to the first bridge arm 111 is relatively high, which can better drive the first bridge arm 111 to turn on, realizing that the energy storage unit 122 supplies power to the first bridge arm 111. In this way, there is no need to wait until the second bridge arm 112 turns on to charge the energy storage unit 122, which can make the second drive signal LO an invalid level and drive the second bridge arm 112 to turn off, realizing that the first bridge arm 111 is always on until the output power of the photovoltaic module needs to be optimized.

[0065] Optionally, the second control signal Dr2 and the first control signal Dr1 can be inverse-phase signals. That is, when the first control signal Dr1 is at an effective level, the second control signal Dr2 is at an invalid level; when the first control signal Dr1 is at an invalid level, the second control signal Dr2 is at an effective level. In this way, when the optocoupler U1 is turned off, the photovoltaic output optocoupler U2 is turned on to supply power to the energy storage unit 122, and the pull-down unit 123 no longer consumes electrical energy, which can reduce power consumption; when the optocoupler U1 is turned on, the photovoltaic output optocoupler U2 is turned off.

[0066] Optionally, referring to Figure 2 , the power supply module 130 further includes a second resistor R2, and the third terminal of the photovoltaic output optocoupler U2 is connected to the second control signal Dr2 through the second resistor R2. The second resistor R2 can limit the current to avoid a large current input to the photovoltaic output optocoupler U2.

[0067] Figure 3 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present invention. Optionally, referring to Figure 2 or Figure 3 , the voltage conversion circuit further includes: a power supply module 150;

[0068] The power supply module 150 includes a power supply unit 151 and a power inductor 152. The power supply unit 151 is connected to the input voltage Vpv, the power supply unit 151 is connected to the first end of the power inductor 152, and the second end of the power inductor 152 is connected to the power supply terminal of the drive unit 121.

[0069] In another embodiment, referring to Figure 3, the power supply module 130 includes a voltage transformation unit 131. The voltage transformation unit 131 includes a first winding L1 and a second winding L2. The first winding L1 is a power inductor 152; the first end of the second winding L2 is connected to the first end of the energy storage unit 122, and the second end of the second winding L2 is connected to the second end of the energy storage unit 122.

[0070] Specifically, the power supply unit 151 may include a DC-DC conversion chip or a Low Dropout Regulator (LDO) chip. The power supply unit 151 can convert the input voltage Vpv, for example, step it down, to facilitate power supply to the driving unit 121. The output voltage of the power supply unit 151 can charge the power inductor 152. When the power inductor 152 discharges, it can provide a power supply to supply power to the driving unit 121.

[0071] Since the first winding L1 of the voltage transformation unit 131 is the power inductor 152, after the power supply unit 151 operates, a voltage is generated across the first winding L1, and a voltage will be generated across the second winding L2, enabling the second winding L2 to supply power to the energy storage unit 122, facilitating the maintenance of the conduction of the first bridge arm 111 and achieving continuous conduction of the first bridge arm 111.

[0072] Moreover, by multiplexing the power inductor 152 as the first winding L1 of the voltage transformation unit 131, the use of components can be reduced, which is beneficial to cost reduction. The voltage transformation unit 131 can continuously supply power to the energy storage unit 122, that is, the voltage transformation unit 131 is always conducting. That is, when the switch module 140 is turned off, the voltage transformation unit 131 is conducting; when the switch module 140 is conducting, the voltage transformation unit 131 is also conducting, achieving the power supply to the energy storage unit 122.

[0073] Optionally, referring to Figure 3 , the voltage transformation unit 131 further includes a first diode D1, a first capacitor C1, and a zener diode D2;

[0074] The first end of the first diode D1 is connected to the first end of the second winding L2, and the second end of the first diode D1 is connected to the first end of the energy storage unit 122;

[0075] The first capacitor C1 is connected between the first end and the second end of the energy storage unit 122;

[0076] The zener diode D2 is connected between the first end and the second end of the energy storage unit 122.

[0077] Specifically, the first diode D1 can perform rectification and filtering, and the first capacitor C1 can perform filtering, so as to output a relatively stable DC voltage, which is convenient for realizing stable power supply to the energy storage unit 122. The zener diode D2 can regulate and clamp the voltage output by the voltage transformation unit 131, avoiding a relatively large output voltage, and can better supply power to the energy storage unit 122.

[0078] Optionally, referring to Figure 2 and Figure 3 , the pull-down unit 123 includes a pull-down resistor R3;

[0079] The first end of the pull-down resistor R3 is electrically connected to the first end of the switch module 140, and the second end of the pull-down resistor R3 is electrically connected to the control end of the first bridge arm 111.

[0080] Specifically, when the switch module 140 is turned on, the switch module 140, the pull-down resistor R3, the first end of the first bridge arm 111, and the control end of the second bridge arm 112 can form a loop, and the junction capacitance of the transistor in the first bridge arm 111 can be quickly released through the pull-down resistor R3, which can improve the efficiency of the first bridge arm 111. When the switch module 140 is turned off, the pull-down resistor R3 can be made not to consume electric energy, which can reduce power consumption and ensure the output power of the photovoltaic module.

[0081] Optionally, referring to Figure 2 and Figure 3 , the driving module 120 further includes a second diode D3 and a third resistor R4;

[0082] The first end of the third resistor R4 is electrically connected to the power supply module 150, the second end of the third resistor R4 is electrically connected to the first end of the second diode D3, and the second end of the second diode D3 is electrically connected to the first end of the energy storage unit 122.

[0083] Specifically, when the power supply module 130 is turned off, the energy storage unit 122 can be charged through the conduction of the second bridge arm 112. When the second bridge arm 112 is turned on, the voltage at the second end of the energy storage unit 122 is pulled down, so that the output power supply of the power supply module 150 charges the energy storage unit 122 through the third resistor R4, and the third resistor R4 can perform current limiting. When the second bridge arm 112 is turned off and the first bridge arm 111 is turned on, the voltage at the second end of the energy storage unit 122 is raised, so that the second diode D3 is turned off, and the output power supply of the power supply module 150 no longer charges the energy storage unit 122. The energy storage unit 122 discharges, and the potential of the first driving signal output by the driving unit 121 to the first bridge arm 111 increases, which can better drive the first bridge arm 111 to conduct, realizing the power supply of the energy storage unit 122 to the first bridge arm 111.

[0084] Optionally, referring to Figure 2 and Figure 3, the energy storage unit 122 includes an energy storage capacitor C2;

[0085] The first pole of the energy storage capacitor C2 is electrically connected to the first bootstrap terminal of the driving unit 121, and the second pole of the energy storage capacitor C2 is electrically connected to the second bootstrap terminal of the driving unit 121.

[0086] Specifically, by setting the energy storage capacitor C2, it is convenient to charge the energy storage capacitor C2 with the output voltage of the power module 150 when the second bridge arm 112 is turned on, or the power supply module 130 charges the energy storage capacitor C2, so that the energy storage capacitor C2 can discharge when the first bridge arm 111 is turned on, so that the potential of the first driving signal output by the driving unit 121 to the first bridge arm 111 increases, and the first bridge arm 111 can be better driven to turn on, realizing that the energy storage unit 122 supplies power to the first bridge arm 111.

[0087] Moreover, when the power supply module 130 supplies power to the energy storage capacitor C2, it can supply power to the energy storage capacitor C2 all the time, and is not affected by the conduction state of the second bridge arm 112, so that the first bridge arm 111 can be turned on all the time.

[0088] Optionally, referring to Figure 2 and Figure 3 , the first bridge arm includes at least one first transistor Q1, and the second bridge arm includes at least one second transistor Q2;

[0089] The first pole of the first transistor Q1 is connected to the input voltage Vpv, the second pole of the first transistor Q1 is connected to the first pole of the second transistor Q2, and the second pole of the second transistor Q2 is grounded.

[0090] Specifically, the first transistor Q1 and the second transistor Q2 can be Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs), that is, the commonly referred to MOS transistors, or Insulate-Gate Bipolar Transistors (IGBTs), which are not limited in this embodiment. The first transistor Q1 and the second transistor Q2 can be N-type transistors or P-type transistors, which are not limited in this embodiment. For example, the first pole of the first transistor Q1 is the drain of the first transistor Q1, the control pole of the first transistor Q1 is the gate of the first transistor Q1, and the second pole of the first transistor Q1 is the source of the first transistor Q1. For example, the first pole of the second transistor Q2 is the drain of the second transistor Q2, the second pole of the second transistor Q2 is the source of the second transistor Q2, and the control pole of the second transistor Q2 is the gate of the second transistor Q2.

[0091] The first transistor Q1 and the second transistor Q2 are connected to form a BUCK buck circuit. When the photovoltaic module is unobstructed and the power supply module 130 supplies power to the energy storage unit 122, the energy storage unit 122 can continuously charge and discharge, thereby continuously supplying power to the first transistor Q1, enabling the first transistor Q1 to be always turned on, and thus outputting the input voltage Vpv. When the photovoltaic module is obstructed, the second transistor Q2 and the first transistor Q1 are alternately turned on. After the input voltage Vpv is step-down converted, the output voltage Vout is obtained, the output power of the photovoltaic module is adjusted, and the maximum power point tracking is achieved.

[0092] It should be noted that Figure 2 and Figure 3 show a case where the first bridge arm 111 includes a first transistor Q1 and the second bridge arm 112 includes a second transistor Q2, but it is not limited thereto.

[0093] Based on the above technical solutions, Figure 4 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present invention. Figure 5 is a schematic structural diagram of another voltage conversion circuit provided by an embodiment of the present invention. Optionally, referring to Figure 4 and Figure 5 , the driving module 120 further includes a second capacitor C3 and a third capacitor C4. The first pole of the second capacitor C3 is connected to the power supply terminal of the driving unit 121, and the second pole of the second capacitor C3 is grounded; the first pole of the third capacitor C4 is connected to the power supply terminal of the driving unit 121, and the second pole of the third capacitor C4 is grounded; the grounding terminal of the driving unit 121 is grounded. The second capacitor C3 and the third capacitor C4 can filter the power supply of the driving unit 121.

[0094] Optionally, referring to Figure 4 and Figure 5 , the first input terminal of the driving unit 121 is connected to a first driving control signal K1, and the second input terminal of the driving unit 121 is connected to a second driving control signal K2. The first driving control signal K1 and the second driving control signal K2 can be sent by a control chip, so that the driving unit 121 outputs a first driving signal HO according to the first driving control signal K1 and outputs a second driving signal LO according to the second driving control signal K2.

[0095] Optionally, referring to Figure 4 and Figure 5 , the driving module 120 further includes a fourth resistor R5. The first output terminal of the driving unit 121 is electrically connected to the control terminal of the first bridge arm 111 through the fourth resistor R5. The fourth resistor R5 can limit the current.

[0096] Optionally, referring to Figure 4 and Figure 5, the driving module 120 further includes a fifth resistor R6 and a third diode D4. The first end of the fifth resistor R6 is connected to the first output end of the driving unit 121, and the second end of the fifth resistor R6 is electrically connected to the control end of the first bridge arm 111 through the third diode D4. The fifth resistor R6 can limit the current.

[0097] Optionally, refer to Figure 4 and Figure 5 , the driving module 120 further includes a sixth resistor R7, a seventh resistor R8 and a fourth diode D5. The second output end of the driving unit 121 is electrically connected to the control end of the second bridge arm 112 through the sixth resistor R7; the first end of the seventh resistor R8 is connected to the second output end of the driving unit 121, and the second end of the seventh resistor R8 is electrically connected to the control end of the second bridge arm 112 through the fourth diode D5. The sixth resistor R7 and the seventh resistor R8 can limit the current.

[0098] Optionally, the power supply unit 151 may include a DC-DC conversion chip and its peripheral circuits. The driving unit 121 may include a half-bridge driving chip.

[0099] It should be noted that Figure 4 and Figure 5 show a case where the first bridge arm 111 includes two first transistors Q1 and the second bridge arm 112 includes two second transistors Q2, but it is not limited thereto.

[0100] The embodiment of the present invention further provides a photovoltaic optimizer. Figure 6 is a schematic circuit diagram of a photovoltaic optimizer provided by the embodiment of the present invention. Refer to Figure 6 , the photovoltaic optimizer includes the voltage conversion circuit 10 provided by any implementation scheme of the present invention. Therefore, the photovoltaic optimizer has the same beneficial effects as the voltage conversion circuit provided by any implementation scheme of the present invention, and will not be described in detail here.

[0101] Optionally, refer to Figure 6, the PV optimizer further includes a control module 20. The control module 20 is connected to the first input terminal of the driving unit 121 in the voltage conversion circuit 10, and the control module 20 is connected to the second input terminal of the driving unit 121. In this way, it is convenient for the control module 20 to output a first driving control signal K1 and a second driving control signal K2 to the driving unit 121, so that the driving unit 121 outputs a first driving signal HO according to the first driving control signal K1 and outputs a second driving signal LO according to the second driving control signal K2, thereby controlling the conduction timing of the first bridge arm 111 and the conduction timing of the second bridge arm 112. Among them, the control module 20 may include a control chip, and the control chip may be a single-chip microcomputer, a digital signal processor (DSP), or a field programmable gate array (FPGA), which is not limited in this embodiment.

[0102] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A voltage conversion circuit, characterized in that, Comprising: A voltage conversion module, including a first arm and a second arm; a first end of the first arm is connected to an input voltage; The voltage conversion module is configured to convert the input voltage to obtain an output voltage; A driving module, including a driving unit, an energy storage unit, and a pull-down unit; the driving unit is respectively connected to control ends of the first arm and the second arm, and the energy storage unit; the driving unit is configured to transmit a driving signal to the voltage conversion module; the energy storage unit is connected to a second end of the first arm, and the energy storage unit is configured to supply power to the first arm when discharging; A power supply module and a switching module; the power supply module is connected to the energy storage unit; the pull-down unit is connected between a first end of the switching module and a control end of the first arm, and a second end of the switching module is connected to the second end of the first arm; the switching module is configured to be turned off in a first state, and the power supply module is configured to be turned on in the first state and supply power to the energy storage unit; the switching module is configured to be turned on in a second state, and the power supply module is configured to be turned on or off in the second state, so that the voltage conversion module converts the input voltage.

2. The voltage conversion circuit according to claim 1, wherein The switching module includes an optocoupler; A third end of the optocoupler is connected to a first control signal, a fourth end of the optocoupler is grounded, a first end of the optocoupler is connected to a first end of the pull-down unit, and a second end of the optocoupler is connected to the second end of the first arm; the optocoupler is configured to conduct in response to an effective level of the first control signal.

3. The voltage conversion circuit according to claim 1, characterized in that, The power supply module includes a photovoltaic output optocoupler; A third end of the photovoltaic output optocoupler is connected to a second control signal, a fourth end of the photovoltaic output optocoupler is grounded, a first end of the photovoltaic output optocoupler is electrically connected to a first end of the energy storage unit, and a second end of the photovoltaic output optocoupler is electrically connected to a second end of the energy storage unit; the photovoltaic output optocoupler is configured to conduct in response to an effective level of the second control signal to output a charging voltage to charge the energy storage unit.

4. The voltage conversion circuit according to claim 1, wherein Further comprising: A power supply module; The power supply module includes a power supply unit and a power inductor, the power supply unit is connected to the input voltage, the power supply unit is connected to a first end of the power inductor, and a second end of the power inductor is connected to a power supply end of the driving unit; The power supply module includes a voltage conversion unit, the voltage conversion unit includes a first winding and a second winding, the first winding is the power inductor; a first end of the second winding is connected to a first end of the energy storage unit, and a second end of the second winding is connected to a second end of the energy storage unit.

5. The voltage conversion circuit according to claim 4, characterized in that, The voltage conversion unit further includes a first diode, a first capacitor, and a zener diode; A first end of the first diode is connected to a first end of the second winding, and a second end of the first diode is connected to a first end of the energy storage unit; The first capacitor is connected between a first end of the energy storage unit and a second end of the energy storage unit; The zener diode is connected between a first end of the energy storage unit and a second end of the energy storage unit.

6. The voltage conversion circuit according to claim 1, wherein The pull-down unit includes a pull-down resistor; The first end of the pull-down resistor is electrically connected to the first end of the switch module, and the second end of the pull-down resistor is electrically connected to the control end of the first arm.

7. The voltage conversion circuit according to claim 1, wherein The driving module further includes a second diode and a third resistor; The first end of the third resistor is electrically connected to the power supply module, the second end of the third resistor is electrically connected to the first end of the second diode, and the second end of the second diode is electrically connected to the first end of the energy storage unit.

8. The voltage conversion circuit according to claim 1, wherein The energy storage unit includes an energy storage capacitor; The first pole of the energy storage capacitor is electrically connected to the first bootstrap terminal of the driving unit, and the second pole of the energy storage capacitor is electrically connected to the second bootstrap terminal of the driving unit.

9. The voltage conversion circuit according to claim 1, wherein The first arm includes at least one first transistor, and the second arm includes at least one second transistor; The first pole of the first transistor is connected to the input voltage, the second pole of the first transistor is connected to the first pole of the second transistor, and the second pole of the second transistor is grounded.

10. A photovoltaic optimizer, characterized in that, A voltage conversion circuit according to any one of claims 1-9 is included.

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