Reverse connection adaptive control circuit, control method, power supply system and photovoltaic air conditioner

Abstract

The application discloses a reverse-connection self-adaptive control circuit, a control method, a power supply system and a photovoltaic air conditioner. The circuit comprises a photovoltaic DC / DC module, wherein the photovoltaic DC / DC module comprises a first photovoltaic DC / DC unit and a second photovoltaic DC / DC unit; the first photovoltaic DC / DC unit is turned on when a photovoltaic cell is connected in positive; and the second photovoltaic DC / DC unit is turned on when the photovoltaic cell is connected in reverse. A switching module is connected with the photovoltaic cell, a DC / AC controller and the first photovoltaic DC / DC unit and the second photovoltaic DC / DC unit respectively, and is used for changing a conduction state of the switching module according to a connection state of the photovoltaic cell, so as to control the first photovoltaic DC / DC unit or the second photovoltaic DC / DC unit to be turned on. Through the application, no matter whether the photovoltaic cell is connected in positive or reverse, the connection relationship between the photovoltaic cell and the DC / AC controller can be adaptively adjusted, so that the power supply system can work normally without manual participation.

Description

Technical Field

[0001] This invention relates to the field of electronic power technology, and more specifically, to a reverse-connection adaptive control circuit, control method, power supply system, and photovoltaic air conditioner. Background Technology

[0002] Figure 1 Here is a structural diagram of a power supply system for an existing photovoltaic air conditioner, such as... Figure 1 As shown, when a photovoltaic cell is directly connected to a photovoltaic DC / DC converter, the switching transistors and inductors at the output of the photovoltaic cell continuously consume electrical energy when the positive and negative terminals are reversed. Furthermore, the photovoltaic cell is close to a short circuit at this time, and the electrical energy output by the photovoltaic cell is converted into heat energy, exacerbating the temperature rise problem within the power supply system. To address these issues, a new power supply method for photovoltaic air conditioners is proposed. Figure 2 Here is a structural diagram of a power supply system for another existing photovoltaic air conditioner, such as... Figure 2 As shown, a DC contactor is set on the side of the photovoltaic cell to realize the connection control between the photovoltaic cell and the photovoltaic DC / DC. However, this structure is costly and can only cut off the power when reversed. Then, the reverse connection problem can be solved by manually adjusting the wiring method. It cannot achieve adaptive connection in the case of reverse connection of photovoltaic cells, and the degree of automation is low.

[0003] There is currently no effective solution to the problem that the power supply system of photovoltaic air conditioners cannot achieve adaptive connection when photovoltaic cells are reverse-connected. Summary of the Invention

[0004] This invention provides a reverse-connection adaptive control circuit, control method, power supply system, and photovoltaic air conditioner to solve the problem that the power supply system of the existing photovoltaic air conditioner cannot achieve adaptive connection when the photovoltaic cells are reverse-connected.

[0005] To solve the above-mentioned technical problems, the present invention provides a reverse-connection adaptive control circuit, wherein the circuit includes:

[0006] A photovoltaic DC / DC module, including a first photovoltaic DC / DC unit and a second photovoltaic DC / DC unit, wherein the first photovoltaic DC / DC unit is turned on when the photovoltaic cell is connected in the correct direction, and the second photovoltaic DC / DC unit is turned on when the photovoltaic cell is connected in the reverse direction;

[0007] The switching module is connected to the photovoltaic cell, the DC / AC controller, the first photovoltaic DC / DC unit, and the second photovoltaic DC / DC unit, respectively. It is used to change its own conduction state according to the wiring state of the photovoltaic cell, thereby controlling the first photovoltaic DC / DC unit or the second photovoltaic DC / DC unit to conduct.

[0008] Furthermore, the switching module includes:

[0009] A first switch has its first end connected to the positive terminal of the photovoltaic cell, its second end connected to the first terminal of the first photovoltaic DC / DC unit, and its third end connected to the second terminal of the second photovoltaic DC / DC unit.

[0010] The second switch has its first end connected to the negative terminal of the photovoltaic cell, its second end connected to the first end of the third switch, and its third end connected to the first end of the second photovoltaic DC / DC unit.

[0011] The third switch has its first end connected to the negative terminal of the DC / AC controller, its second end connected to the second end of the first photovoltaic DC / DC unit, and its third end connected to the second end of the second photovoltaic DC / DC unit.

[0012] The third terminal of the first photovoltaic DC / DC unit and the third terminal of the second photovoltaic DC / DC unit are connected to the positive terminal of the DC / AC controller.

[0013] Furthermore, the first photovoltaic DC / DC unit includes:

[0014] The first inductor has its first end connected to the second end of the first switch, and its second end connected to the first end of the first switching transistor.

[0015] The second terminal of the first switching transistor is connected to the second terminal of the third switch;

[0016] A diode, the positive terminal of which is connected between the second terminal of the first inductor and the first terminal of the first switching transistor, and the negative terminal of which is connected to the positive terminal of the DC / AC controller.

[0017] Furthermore, the second photovoltaic DC / DC unit includes:

[0018] The second inductor has its first end connected to the third end of the second switch, and its second end connected to the first end of the second switch transistor, the second end of the first inductor, and the first end of the first switch transistor, respectively.

[0019] The second switch has its second terminal connected to the third terminal of the first switch and the third terminal of the third switch, respectively.

[0020] The second photovoltaic DC / DC unit includes the diode.

[0021] Furthermore, the circuit also includes:

[0022] The sampling module is connected to a current sensor, which is located at the connection points of the second end of the first inductor, the second end of the second inductor, the first end of the first switch, and the second switch. The current sensor is used to collect the current output by the photovoltaic cell and generate a sampling signal based on the current output by the photovoltaic cell.

[0023] Furthermore, the sampling module includes:

[0024] An operational amplifier has its non-inverting input connected to the current sensor, its inverting input receiving a reference voltage, and its output connected to its own inverting input, as well as to the control module.

[0025] Furthermore, the circuit also includes:

[0026] The control module is used to output a control signal based on the sampling signal generated by the current sampling module, thereby controlling the conduction state of the switching module and the switching on / off state of the first and second switching transistors.

[0027] Furthermore, the circuit also includes:

[0028] An auxiliary power supply, whose input is connected to the power grid and whose output is connected to the sampling module and the control module respectively, is used to supply power to the sampling module and the control module.

[0029] The present invention also provides a power supply system, including a photovoltaic cell and a DC / AC controller, and further including the aforementioned reverse connection adaptive control circuit.

[0030] The present invention also provides a photovoltaic air conditioner, including the above-mentioned power supply system.

[0031] The present invention also provides a control method applied to the above-mentioned reverse-connection adaptive control circuit, the control method comprising:

[0032] After the photovoltaic cell is connected to the DC / AC controller, it is determined whether the photovoltaic cell is reverse-connected;

[0033] If not, the control switching module is in the first conduction state, thereby controlling the first photovoltaic DC / DC unit to conduct, and controlling the first switching transistor in the first photovoltaic DC / DC unit to be intermittently turned on and off;

[0034] If so, the control switching module is set to the second conduction state, thereby controlling the second photovoltaic DC / DC unit to conduct and controlling the second switching transistor in the second photovoltaic DC / DC unit to intermittently turn on and off.

[0035] Further, determining whether the photovoltaic cell is reverse-connected includes:

[0036] Determine whether the current output by the photovoltaic cell is greater than a preset threshold;

[0037] If so, it is determined that the photovoltaic cell is not reverse-connected;

[0038] If not, then the photovoltaic cell is determined to be reverse-connected.

[0039] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the above-described control method.

[0040] By applying the technical solution of this invention, a first photovoltaic DC / DC unit and a second photovoltaic DC / DC unit are added to the circuit structure of the existing photovoltaic air conditioner power supply system. The first photovoltaic DC / DC unit is turned on when the photovoltaic cell is connected in the correct direction, and the second photovoltaic DC / DC unit is turned on when the photovoltaic cell is connected in the reverse direction. By changing its own conduction state according to the wiring state of the photovoltaic cell through the switching module, the first photovoltaic DC / DC unit or the second photovoltaic DC / DC unit is controlled to be turned on. This ensures that the connection relationship between the photovoltaic cell and the DC / AC controller can be adaptively adjusted regardless of whether the photovoltaic cell is connected in the correct direction or in the reverse direction, thereby ensuring the normal operation of the power supply system without manual intervention. Attached Figure Description

[0041] Figure 1 This is a structural diagram of a power supply system for an existing photovoltaic air conditioner;

[0042] Figure 2 This is a structural diagram of a power supply system for another existing photovoltaic air conditioner;

[0043] Figure 3 This is a structural diagram of the reverse-connection adaptive control circuit according to an embodiment of the present invention;

[0044] Figure 4 This is a structural diagram of the sampling module according to an embodiment of the present invention;

[0045] Figure 5 A flowchart of a control method according to an embodiment of the present invention;

[0046] Figure 6 This is a flowchart of a control method according to another embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0049] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0050] It should be understood that although the terms first, second, third, etc., may be used to describe switches in the embodiments of the present invention, these switches should not be limited to these terms. These terms are only used to distinguish different switches. For example, without departing from the scope of the embodiments of the present invention, a first switch may also be referred to as a second switch, and similarly, a second switch may also be referred to as a first switch.

[0051] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0052] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0053] The optional embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0054] Example 1

[0055] This embodiment provides a reverse-connection adaptive control circuit. Figure 3 This is a structural diagram of the reverse-connection adaptive control circuit according to an embodiment of the present invention, such as... Figure 3 As shown, the reverse-connection adaptive control circuit is disposed between the photovoltaic cell 10 and the DC / AC controller 20, and the circuit includes:

[0056] A photovoltaic DC / DC module includes a first photovoltaic DC / DC unit and a second photovoltaic DC / DC unit, wherein the first photovoltaic DC / DC unit is turned on when the photovoltaic cell 10 is connected in the forward direction and the second photovoltaic DC / DC unit is turned on when the photovoltaic cell 10 is connected in the reverse direction.

[0057] The switching module is connected to the photovoltaic cell 10, the DC / AC controller 20, the first photovoltaic DC / DC unit, and the second photovoltaic DC / DC unit, respectively. It is used to change its own conduction state according to the wiring state of the photovoltaic cell 10, thereby controlling the first photovoltaic DC / DC unit or the second photovoltaic DC / DC unit to conduct.

[0058] The reverse-connection adaptive control circuit of this embodiment adds a first photovoltaic DC / DC unit and a second photovoltaic DC / DC unit to the existing power supply system circuit structure of the photovoltaic air conditioner. The first photovoltaic DC / DC unit is turned on when the photovoltaic cell 10 is connected in the correct direction, and the second photovoltaic DC / DC unit is turned on when the photovoltaic cell 10 is connected in the reverse direction. By changing its own conduction state according to the wiring state of the photovoltaic cell 10 through the switching module, the first photovoltaic DC / DC unit or the second photovoltaic DC / DC unit is turned on. This ensures that the connection relationship between the photovoltaic cell and the DC / AC controller can be adaptively adjusted regardless of whether the photovoltaic cell is connected in the correct or reverse direction, thereby ensuring the normal operation of the power supply system without manual intervention.

[0059] In practical applications, a DC / DC unit comprises an inductor, a switching transistor, and a diode to form a first BOOST boost circuit (i.e., the first photovoltaic DC / DC unit) to achieve the boost function. The inductor and diode are connected in series (the inductor is connected to the positive terminal of the diode) between the positive terminal of the photovoltaic cell and the positive terminal of the DC / AC controller. The drain of the switching transistor is connected between the inductor and the diode, and the source is connected between the negative terminal of the photovoltaic cell and the negative terminal of the DC / AC controller. When the photovoltaic cell is reverse-connected, the positive terminal of the photovoltaic cell is actually the negative terminal, and vice versa. Therefore, it is necessary to change the connection relationship between the positive and negative terminals of the photovoltaic cell and the aforementioned inductor, switching transistor, and diode. Considering that once the structure is determined, the connection relationship cannot be easily changed, another set of inductor, switching transistor, and diode can be added. Since the diode is not directly connected to the positive and negative terminals of the photovoltaic cell, the positive terminal component of the photovoltaic cell can be reused. Only one more inductor and switching transistor are needed, which, together with the reused diode, form a second BOOST boost circuit (i.e., the second photovoltaic DC / DC unit). The switching module (DC / DC unit) disconnects the first BOOST boost circuit and connects the second BOOST boost circuit when the photovoltaic cell is reverse-connected, thus achieving adaptive control under reverse connection conditions. To separately control the conduction of the first and second BOOST boost circuits, the switching module includes: a first switch K1, whose first terminal is connected to the positive terminal of the photovoltaic cell 10, its second terminal is connected to the first terminal of the first photovoltaic DC / DC unit, and its third terminal is connected to the second terminal of the second photovoltaic DC / DC unit; a second switch K2, whose first terminal is connected to the negative terminal of the photovoltaic cell 10, its second terminal is connected to the first terminal of the third switch K3, and its third terminal is connected to the first terminal of the second photovoltaic DC / DC unit; a third switch K3, whose first terminal is also connected to the negative terminal Vbus- of the DC / AC controller 20, its second terminal is connected to the second terminal of the first photovoltaic DC / DC unit, and its third terminal is connected to the second terminal of the second photovoltaic DC / DC unit; the third terminals of the first and second photovoltaic DC / DC units are connected to the positive terminal Vbus+ of the DC / AC controller 20.

[0060] The first switch K1, the second switch K2, and the third switch K3 mentioned above are all relays. The first end of the first switch K1 is the stationary contact 0 of the relay, the second end is the normally closed contact 1 of the relay, and the third end is the normally open contact 2 of the relay. Similarly, the first end of the second switch K2 is the stationary contact 0 of the relay, the second end is the normally closed contact 1 of the relay, and the third end is the normally open contact 2 of the relay. The first end of the third switch K3 is the stationary contact 0 of the relay, the second end is the normally closed contact 1 of the relay, and the third end is the normally open contact 2 of the relay.

[0061] To form a BOOST boost circuit, the first photovoltaic DC / DC unit includes:

[0062] The first inductor L1 has its first end connected to the second end of the first switch K1, and its second end connected to the first end of the first switching transistor Q1; the second end of the first switching transistor Q1 is connected to the second end of the third switch K3; the diode D1 has its positive terminal connected between the second end of the first inductor L1 and the first end of the first switching transistor Q1, and its negative terminal connected to the positive terminal Vbus+ of the DC / AC controller 20.

[0063] The second photovoltaic DC / DC unit includes: a second inductor L2, whose first end is connected to the third end of the second switch K2, and whose second end is connected to the first end of the second switch Q2, the second end of the first inductor L1, and the first end of the first switch Q1; the second switch Q2, whose second end is connected to the third end of the first switch K1 and the third end of the third switch K3; and a diode D1. In other words, to save on components, the first and second photovoltaic DC / DC units share a single diode.

[0064] If the photovoltaic cell is connected in reverse, its output current will be smaller than the current when it is connected in the correct direction. In order to collect the output current of the photovoltaic cell and thus determine whether the photovoltaic cell is connected in reverse, the circuit also includes: a sampling module 30, which is connected to a current sensor U1. The current sensor U1 is set at the connection of the second end of the first inductor L1, the second end of the second inductor L2, the first end of the first switch K1, and the second switch K2, and is used to collect the output current of the photovoltaic cell 10 and generate a sampling signal based on the output current of the photovoltaic cell 10.

[0065] Figure 4 This is a structural diagram of the sampling module according to an embodiment of the present invention, such as... Figure 4 As shown, the sampling module 30 includes: an operational amplifier A, whose non-inverting input is connected to the current sensor U1, inputting U1_Out; its inverting input is connected to a reference voltage U1_Ref; its output is connected to its own inverting input and is also connected to a control module for outputting the sampling voltage V. o .

[0066] The aforementioned current sensor can employ a Hall effect device. For example, when the photovoltaic cell is connected in the correct orientation, U1_Out outputs 2.5V, and the value of U1_Ref is set to 2.5V. Assuming Vref is set to 1.5V, the sampling voltage Vo output by the sampling module 30 will be 1.5V. When the photovoltaic cell is connected in reverse, the current output by the photovoltaic cell will decrease, and the value of U1_Out will be less than the value of U1_Ref, resulting in the sampling voltage Vo being less than 1.5V. Therefore, by using the value of the sampling voltage output by the sampling module 30, it can be determined whether the current output by the photovoltaic cell is less than the normal value, and thus determine whether the photovoltaic cell is connected in reverse.

[0067] like Figure 3 As shown, the circuit further includes: a control module 40, used to control the sampling voltage V generated by the current sampling module 30. o Output control signals to control the conduction state of the switching module.

[0068] In order to provide power to the sampling module 30 and the control module 40 mentioned above, such as Figure 3 As shown, the circuit also includes an auxiliary power supply 50, whose input terminal is connected to the power grid and whose output terminal is connected to the sampling module 30 and the control module 40 respectively, for supplying power to the sampling module 30 and the control module 40.

[0069] In summary, the reverse connection adaptive control circuit of this embodiment adds a second switch Q2, a second inductor L2, a first switch K1, a second switch K2, and a third switch K3 to the existing structure. The photovoltaic DC / DC module in this embodiment is composed of a first inductor L1, a first switch Q1, a diode D1, a second inductor L2, and a second switch Q2. A DC / AC controller is also included between the photovoltaic cell and the photovoltaic air conditioner. The DC / AC controller is also connected to the power grid. The above-mentioned reverse connection adaptive control circuit also includes an auxiliary power supply 50, a control module 40, and a sampling module 30. The photovoltaic DC / DC converter is connected between the photovoltaic cell module and the DC bus, the bidirectional DC / AC controller is connected between the DC bus and the power grid, the auxiliary power supply 50 supplies power to the control module 40 and the sampling module 30, the sampling module 30 can collect the current output by the photovoltaic cell, and the control module 40 can output control signals S_Q1, S_Q2, S_K1, S_K2, and S_K3 to control the opening and closing of the first switch Q1, the second switch Q2, the first switch K1, the second switch K2, and the third switch K3, respectively.

[0070] The specific working process of the above reverse-connection adaptive control circuit is as follows:

[0071] When the photovoltaic input terminal is connected correctly, the sampling module 30 can collect the current signal output by the photovoltaic cell, generate a sampling voltage Vo, and transmit it to the control module 40. The control module 40 determines the positive and negative terminals of the photovoltaic cell are connected correctly based on the sampling voltage Vo, and then sends a control signal S_Q1 to make the first switch Q1 intermittently switch on and off according to a preset duty cycle. The photovoltaic cell is connected and working normally. At this time, the first switch K1, the second switch K2, and the third switch K3 are de-energized. The stationary contact 0 of the first switch K1, the second switch K2, and the third switch K3 are connected to the normally closed contact 1, and the first photovoltaic DC / DC unit composed of the first inductor L1, the first switch Q1, and the diode D1 is turned on and works normally.

[0072] When the positive and negative terminals of the photovoltaic cell are reversed, the sampling module 30 can collect the current signal output by the photovoltaic cell, generate a sampling voltage Vo, and transmit it to the control module 40. The control module 40 determines that the positive and negative terminals of the photovoltaic cell are reversed based on the sampling voltage Vo, and then sends control signals S_K1 / S_K2 / S_K3 to control the first switch K1, the second switch K2, and the third switch K3 to be energized. The stationary contact 0 of the first switch K1, the second switch K2, and the third switch K3 is de-energized and connected to the normally open contact 2. At the same time, the second switch Q2 is controlled to be intermittently switched on and off according to a preset duty cycle, so that the second photovoltaic DC / DC unit composed of the second inductor L2, the second switch Q2, and the diode D1 is turned on and works normally.

[0073] The solution in this embodiment ensures that the system can operate normally regardless of whether the positive and negative terminals are reversed when photovoltaic cells are connected, without the need for manual intervention. It also solves the problem of reverse connection of wiring during photovoltaic side engineering installation, thereby solving the problem of increased system temperature rise caused by reverse photovoltaic connection.

[0074] Example 2

[0075] This embodiment provides a power supply system, including a photovoltaic cell and a DC / AC controller, and also includes the reverse connection adaptive control circuit in the above embodiment, which is used to ensure that the photovoltaic cell can adaptively adjust the connection relationship between the photovoltaic cell and the DC / AC controller regardless of whether it is connected in the correct or reverse direction, thereby ensuring the normal operation of the power supply system without manual intervention.

[0076] Example 3

[0077] This embodiment provides a photovoltaic air conditioner, including the power supply system described in the above embodiment, which is used to ensure that the connection relationship between the photovoltaic cells and the DC / AC controller can be adaptively adjusted regardless of whether the photovoltaic cells are connected in the correct or reverse direction, thereby ensuring the normal operation of the power supply system without manual intervention, and thus ensuring the normal operation of the entire photovoltaic air conditioner.

[0078] Example 4

[0079] This embodiment provides a control method applied to the aforementioned reverse-connection adaptive control circuit. Figure 5 A flowchart of a control method according to an embodiment of the present invention is shown below. Figure 5 As shown, the control method includes:

[0080] S101 determines whether the photovoltaic cell is reverse-connected after it is connected to the DC / AC controller.

[0081] S102, if not, then control the switching module to the first conduction state, thereby controlling the first photovoltaic DC / DC unit to conduct, and controlling the first switching transistor in the first photovoltaic DC / DC unit to intermittently turn on and off.

[0082] S103, if so, control the switching module to the second conduction state, thereby controlling the second photovoltaic DC / DC unit to conduct, and controlling the second switching tube in the second photovoltaic DC / DC unit to intermittently turn on and off.

[0083] As shown above, if a photovoltaic cell is connected in reverse, its output current will be smaller than that when it is connected in the correct direction. Therefore, determining whether a photovoltaic cell is connected in reverse includes: determining whether the output current of the photovoltaic cell is greater than a preset threshold; if yes, the photovoltaic cell is determined not to be connected in reverse; if no, the photovoltaic cell is determined to be connected in reverse.

[0084] The control method in this embodiment determines whether the photovoltaic cell is reverse-connected after it is connected to the DC / AC controller. If reverse-connected, the control switching module is in a second conducting state, thereby controlling the second photovoltaic DC / DC unit to conduct and intermittently switching the second switching transistor in the second photovoltaic DC / DC unit on and off. If correctly connected, the control switching module is in a first conducting state, thereby controlling the first photovoltaic DC / DC unit to conduct and intermittently switching the first switching transistor in the first photovoltaic DC / DC unit on and off. This ensures that the connection between the photovoltaic cell and the DC / AC controller can be adaptively adjusted regardless of whether the photovoltaic cell is correctly or reverse-connected, thus ensuring the normal operation of the power supply system without manual intervention.

[0085] Specifically, determining whether the current output by the photovoltaic cell is greater than a preset threshold includes: determining whether the sampling voltage output by the sampling module is greater than a preset threshold; if so, determining that the current output by the photovoltaic cell is greater than the preset threshold; if not, determining that the current output by the photovoltaic cell is less than or equal to the preset threshold.

[0086] Figure 6 A flowchart of a control method according to another embodiment of the present invention is shown below. Figure 6 As shown, the control method includes the following preferred implementation steps:

[0087] S1 collects the current output from the photovoltaic cell.

[0088] Specifically, the sampling module 30 collects the current output by the photovoltaic cell. The sampling module 30 is connected to a current sensor U1, which is located at the connection point of the second terminal of the first inductor L1, the second terminal of the second inductor L2, the first terminal of the first switch K1, and the second switch K2. It is used to collect the current output by the photovoltaic cell 10 and generate a sampling signal based on the current output by the photovoltaic cell 10. Specifically, the sampling module 30 includes: an operational amplifier A, whose non-inverting input is connected to the current sensor U1, inputting U1_Out; its inverting input receives a reference voltage U1_Ref; its output is connected to its own inverting input; and it is also connected to a control module for outputting the sampling voltage V. o The aforementioned current sensor can employ a Hall effect device. For example, when the photovoltaic cell is connected in the correct orientation, U1_Out outputs 2.5V, and the value of U1_Ref is set to 2.5V. Assuming Vref is set to 1.5V, the sampling voltage Vo output by the sampling module 30 will be 1.5V. When the photovoltaic cell is connected in reverse, the current output by the photovoltaic cell will decrease, and the value of U1_Out will be less than the value of U1_Ref, resulting in the sampling voltage Vo being less than 1.5V. Therefore, by using the value of the sampling voltage output by the sampling module 30, it can be determined whether the current output by the photovoltaic cell is less than the normal value, and thus whether the photovoltaic cell is connected in reverse.

[0089] S2, determine whether the current output by the photovoltaic cell is greater than the preset threshold. If yes, proceed to step S3; otherwise, proceed to step S4.

[0090] S3, determine that the photovoltaic cell is positively connected, control the first switch K1, the second switch K2, and the third switch K3 to de-energize, the static contact 0 of the first switch K1, the second switch K2, and the third switch K3 to connect with the normally closed contact 1, thereby controlling the first photovoltaic DC / DC unit composed of the first switch Q1, the first inductor L1, and the diode D1 to conduct, and at the same time controlling the first switch Q1 to intermittently switch on and off according to the preset duty cycle.

[0091] S4 determines the forward or reverse connection of the photovoltaic cell, controls the first switch K1, the second switch K2, and the third switch K3 to be de-energized, and the stationary contact 0 of the first switch K1, the second switch K2, and the third switch K3 to be connected to the normally open contact 2, thereby controlling the first photovoltaic DC / DC unit composed of the second switch tube Q2, the second inductor L2, and the diode D1 to be turned on, and at the same time controlling the second switch Q2 to be intermittently turned on and off according to the preset duty cycle.

[0092] Example 5

[0093] This embodiment provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the control method of the above embodiment.

[0094] The circuit embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0095] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reverse connection adaptive control circuit, disposed between a photovoltaic cell and a DC / AC controller, characterized in that, The circuit includes: A photovoltaic DC / DC module, including a first photovoltaic DC / DC unit and a second photovoltaic DC / DC unit, wherein the first photovoltaic DC / DC unit is turned on when the photovoltaic cell is connected in the correct direction, and the second photovoltaic DC / DC unit is turned on when the photovoltaic cell is connected in the reverse direction; The switching module is connected to the photovoltaic cell, the DC / AC controller, the first photovoltaic DC / DC unit, and the second photovoltaic DC / DC unit, respectively. It is used to change its own conduction state according to the wiring state of the photovoltaic cell, thereby controlling the first photovoltaic DC / DC unit or the second photovoltaic DC / DC unit to conduct. The switching module includes: a first switch, the first end of which is connected to the positive terminal of the photovoltaic cell, the second end of which is connected to the first terminal of the first photovoltaic DC / DC unit, and the third end of which is connected to the second terminal of the second photovoltaic DC / DC unit; a second switch, the first end of which is connected to the negative terminal of the photovoltaic cell, the second end of which is connected to the first terminal of a third switch, and the third end of which is connected to the first terminal of the second photovoltaic DC / DC unit; the third switch, the first end of which is also connected to the negative terminal of the DC / AC controller, the second end of which is connected to the second terminal of the first photovoltaic DC / DC unit, and the third end of which is connected to the second terminal of the second photovoltaic DC / DC unit; the third terminals of the first photovoltaic DC / DC unit and the third terminals of the second photovoltaic DC / DC unit are connected to the positive terminal of the DC / AC controller; The first photovoltaic DC / DC unit includes: a first inductor, the first end of which is connected to the second end of the first switch, and the second end of which is connected to the first end of the first switching transistor; the first switching transistor, the second end of which is connected to the second end of the third switch; and a diode, the positive terminal of which is connected between the second end of the first inductor and the first end of the first switching transistor, and the negative terminal of which is connected to the positive terminal of the DC / AC controller. The second photovoltaic DC / DC unit includes: a second inductor, the first end of which is connected to the third end of the second switch, and the second end of which is connected to the first end of the second switching transistor, the second end of the first inductor, and the first end of the first switching transistor; the second switching transistor, the second end of which is connected to the third end of the first switch and the third end of the third switch; and the second photovoltaic DC / DC unit includes the diode.

2. The circuit of claim 1, wherein, The circuit also includes: The sampling module is connected to a current sensor, which is located at the connection points of the second end of the first inductor, the second end of the second inductor, the first end of the first switch, and the second switch. The current sensor is used to collect the current output by the photovoltaic cell and generate a sampling signal based on the current output by the photovoltaic cell.

3. The circuit according to claim 2, characterized in that, The sampling module includes: An operational amplifier has its non-inverting input connected to the current sensor, its inverting input receiving a reference voltage, and its output connected to its own inverting input, as well as to the control module.

4. The circuit according to claim 2, characterized in that, The circuit also includes: The control module is used to output a control signal based on the sampling signal generated by the current sampling module, thereby controlling the conduction state of the switching module and the on / off state of the first and second switching transistors.

5. The circuit according to claim 4, characterized in that, The circuit also includes: An auxiliary power supply, whose input is connected to the power grid and whose output is connected to the sampling module and the control module respectively, is used to supply power to the sampling module and the control module.

6. A power supply system comprising a photovoltaic cell and a DC / AC controller, characterized in that, It also includes the reverse-connection adaptive control circuit as described in any one of claims 1 to 5.

7. A photovoltaic air conditioner, characterized in that, Includes the power supply system described in claim 6.

8. A control method applied to the reverse-connection adaptive control circuit according to any one of claims 1 to 5, characterized in that, The control method includes: After the photovoltaic cell is connected to the DC / AC controller, it is determined whether the photovoltaic cell is reverse-connected; If not, the control switching module is in the first conduction state, thereby controlling the first photovoltaic DC / DC unit to conduct, and controlling the first switching transistor in the first photovoltaic DC / DC unit to be intermittently turned on and off; If so, the control switching module is set to the second conduction state, thereby controlling the second photovoltaic DC / DC unit to conduct and controlling the second switching transistor in the second photovoltaic DC / DC unit to intermittently turn on and off.

9. The control method according to claim 8, characterized in that, Determining whether the photovoltaic cell is reverse-connected includes: Determine whether the current output by the photovoltaic cell is greater than a preset threshold; If so, it is determined that the photovoltaic cell is not reverse-connected; If not, then the photovoltaic cell is determined to be reverse-connected.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the control method as described in claim 8 or 9.

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