CN115276188A - Reverse connection self-adaptive control circuit, control method, power supply system and photovoltaic air conditioner - Google Patents

Reverse connection self-adaptive control circuit, control method, power supply system and photovoltaic air conditioner Download PDF

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Publication number
CN115276188A
CN115276188A CN202211072248.XA CN202211072248A CN115276188A CN 115276188 A CN115276188 A CN 115276188A CN 202211072248 A CN202211072248 A CN 202211072248A CN 115276188 A CN115276188 A CN 115276188A
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CN
China
Prior art keywords
photovoltaic
unit
switch
terminal
photovoltaic cell
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Pending
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CN202211072248.XA
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Chinese (zh)
Inventor
陈宁宁
黄猛
黄颂儒
安宏迪
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Gree Electric Appliances Inc of Zhuhai
Guochuang Energy Internet Innovation Center Guangdong Co Ltd
Original Assignee
Gree Electric Appliances Inc of Zhuhai
Guochuang Energy Internet Innovation Center Guangdong Co Ltd
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Priority to CN202211072248.XA priority Critical patent/CN115276188A/en
Publication of CN115276188A publication Critical patent/CN115276188A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/0034—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using reverse polarity correcting or protecting circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/88—Electrical aspects, e.g. circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
    • H02H11/002—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/20—Charging or discharging characterised by the power electronics converter
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

The invention discloses a reverse connection self-adaptive control circuit, a control method, a power supply system and a photovoltaic air conditioner. Wherein, this circuit includes: the photovoltaic DC/DC module comprises a first photovoltaic DC/DC unit and a second photovoltaic DC/DC unit, wherein the first photovoltaic DC/DC unit is conducted when the photovoltaic cell is in positive connection, and the second photovoltaic DC/DC unit is conducted when the photovoltaic cell is in reverse connection; and the switching module is respectively connected with the photovoltaic battery, the DC/AC controller, the first photovoltaic DC/DC unit and the second photovoltaic DC/DC unit and is used for changing the conduction state of the switching module according to the wiring state of the photovoltaic battery so as to control the conduction of the first photovoltaic DC/DC unit or the second photovoltaic DC/DC unit. According to the invention, the connection relation between the photovoltaic cell and the DC/AC controller can be adaptively adjusted no matter the photovoltaic cell is in positive connection or reverse connection, so that the normal work of a power supply system is ensured without manual participation.

Description

Reverse connection self-adaptive control circuit, control method, power supply system and photovoltaic air conditioner
Technical Field
The invention relates to the technical field of electronic power, in particular to a reverse connection self-adaptive control circuit, a control method, a power supply system and a photovoltaic air conditioner.
Background
Fig. 1 is a structural diagram of a power supply system of an existing photovoltaic air conditioner, as shown in fig. 1, a photovoltaic cell is directly connected to a photovoltaic DC/DC, when the photovoltaic is connected in a positive and negative reverse direction, a switching tube and an inductor at an output end of the photovoltaic cell always consume electric energy, and at the moment, the photovoltaic cell is close to a short circuit, the electric energy output by the photovoltaic cell is converted into heat energy to be consumed, and the problem of internal temperature rise of the power supply system is aggravated.
Aiming at the problem that the power supply system of the photovoltaic air conditioner in the prior art cannot realize the self-adaptive connection under the condition of the reverse connection of the photovoltaic battery, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the invention provides a reverse connection self-adaptive control circuit, a control method, a power supply system and a photovoltaic air conditioner, and aims to solve the problem that the power supply system of the photovoltaic air conditioner in the prior art cannot realize self-adaptive connection under the condition of reverse connection of a photovoltaic battery.
In order to solve the above technical problem, the present invention provides a reverse connection adaptive control circuit, wherein the circuit comprises:
a photovoltaic DC/DC module including a first photovoltaic DC/DC unit that conducts when the photovoltaic cell is forward connected and a second photovoltaic DC/DC unit that conducts when the photovoltaic cell is reverse connected;
and the switching module is respectively connected with the photovoltaic battery, the DC/AC controller, the first photovoltaic DC/DC unit and the second photovoltaic DC/DC unit and is used for changing the conduction state of the switching module according to the wiring state of the photovoltaic battery so as to control the conduction of the first photovoltaic DC/DC unit or the second photovoltaic DC/DC unit.
Further, the switching module includes:
a first switch having a first terminal connected to the positive terminal of the photovoltaic cell, a second terminal connected to the first terminal of the first photovoltaic DC/DC unit, and a third terminal connected to the second terminal of the second photovoltaic DC/DC unit;
a second switch having a first terminal connected to the negative terminal of the photovoltaic cell, a second terminal connected to a first terminal of a third switch, and a third terminal connected to a first terminal of the second photovoltaic DC/DC unit;
the first end of the third switch is also connected with the negative electrode terminal of the DC/AC controller, the second end of the third switch is connected with the second end of the first photovoltaic DC/DC unit, and the third end of the third switch is connected with the second end of the second photovoltaic DC/DC unit;
the third terminal of the first photovoltaic DC/DC unit and the third terminal of the second photovoltaic DC/DC unit are connected with the positive terminal of the DC/AC controller.
Further, the first photovoltaic DC/DC unit includes:
a first end of the first inductor is connected with the second end of the first switch, and a second end of the first inductor is connected with the first end of the first switch tube;
the second end of the first switch tube is connected with the second end of the third switch;
and the anode of the diode is connected between the second end of the first inductor and the first end of the first switching tube, and the cathode of the diode is connected with the anode terminal of the DC/AC controller.
Further, the second photovoltaic DC/DC unit includes:
a first end of the second inductor is connected with a third end of the second switch, and a second end of the second inductor is connected with a first end of a second switch tube, a second end of the first inductor and a first end of the first switch tube respectively;
a second end of the second switch tube is connected with a third end of the first switch and a third end of the third switch respectively;
the second photovoltaic DC/DC unit includes the diode.
Further, the circuit further comprises:
the sampling module is connected with a current sensor, the current sensor is arranged at the second end of the first inductor, the second end of the second inductor, the first end of the first switch and the joint of the second switch and used for collecting the current output by the photovoltaic cell and generating a sampling signal according to the current output by the photovoltaic cell.
Further, the sampling module includes:
and the non-inverting input end of the operational amplifier is connected with the current sensor, the inverting input end of the operational amplifier inputs reference voltage, and the output end of the operational amplifier is connected with the inverting input end of the operational amplifier and the control module.
Further, the circuit further comprises:
and the control module is used for outputting a control signal according to the sampling signal generated by the current sampling module so as to control the conduction state of the switching module and the on-off of the first switch tube and the second switch tube.
Further, the circuit further comprises:
and the input end of the auxiliary power supply is connected with a power grid, and the output end of the auxiliary power supply is respectively connected with the sampling module and the control module and is used for supplying power to the sampling module and the control module.
The invention also provides a power supply system which comprises a photovoltaic cell, a DC/AC controller and the reverse connection self-adaptive control circuit.
The invention further provides a photovoltaic air conditioner which comprises the power supply system.
The invention also provides a control method, which is applied to the reverse connection self-adaptive control circuit and comprises the following steps:
after the photovoltaic cell is connected with the DC/AC controller, judging whether the photovoltaic cell is reversely connected;
if not, the switching module is controlled to be in a first conduction state, so that the first photovoltaic DC/DC unit is controlled to be conducted, and the first switching tube in the first photovoltaic DC/DC unit is controlled to be intermittently switched on and off;
if yes, the switching module is controlled to be in a second conduction state, the second photovoltaic DC/DC unit is further controlled to be conducted, and the second switch tube in the second photovoltaic DC/DC unit is controlled to be switched on and off intermittently.
Further, judging whether the photovoltaic cells are reversely connected comprises the following steps:
judging whether the current output by the photovoltaic cell is greater than a preset threshold value or not;
if yes, judging that the photovoltaic cell is not reversely connected;
and if not, judging that the photovoltaic cell is reversely connected.
The present invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the above-described control method.
By applying the technical scheme of the invention, the first photovoltaic DC/DC unit and the second photovoltaic DC/DC unit are additionally arranged in the circuit structure of the power supply system of the existing photovoltaic air conditioner, the first photovoltaic DC/DC unit is conducted when the photovoltaic cell is in positive connection, the second photovoltaic DC/DC unit is conducted when the photovoltaic cell is in reverse connection, the conduction state of the first photovoltaic DC/DC unit or the second photovoltaic DC/DC unit is changed through the switching module according to the connection state of the photovoltaic cell, and then the conduction of the first photovoltaic DC/DC unit or the second photovoltaic DC/DC unit is controlled, so that the connection relation between the photovoltaic cell and the DC/AC controller can be adaptively adjusted no matter the photovoltaic cell is in positive connection or reverse connection, the normal work of the power supply system is further ensured, and manual participation is not needed.
Drawings
Fig. 1 is a structural diagram of a power supply system of a conventional photovoltaic air conditioner;
fig. 2 is a structural diagram of another existing power supply system of a photovoltaic air conditioner;
FIG. 3 is a block diagram of a reverse-connect adaptive control circuit according to an embodiment of the present invention;
FIG. 4 is a block diagram of a sampling module according to an embodiment of the present invention;
FIG. 5 is a flow chart of a control method according to an embodiment of the invention;
fig. 6 is a flowchart of a control method according to another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two.
It should be understood that the term "and/or" as used herein is merely a relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B, may represent: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
It should be understood that although the terms first, second, third, etc. may be used to describe the switches in embodiments of the present invention, the switches should not be limited to these terms. These terms are only used to distinguish different switches. For example, 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, without departing from the scope of embodiments of the present invention.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrase "if determined" or "if detected (a stated condition or event)" may be interpreted as "upon determining" or "in response to determining" or "upon detecting (a stated condition or event)" or "in response to detecting (a stated condition or event)", depending on the context.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another like element in a commodity or device comprising the element.
Alternative embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Example 1
The present embodiment provides a reverse connection adaptive control circuit, and fig. 3 is a structural diagram of a reverse connection adaptive control circuit according to an embodiment of the present invention, as shown in fig. 3, the reverse connection adaptive control circuit is disposed between a photovoltaic cell 10 and a DC/AC controller 20, and the circuit includes:
a photovoltaic DC/DC module including a first photovoltaic DC/DC unit that is turned on when the photovoltaic cell 10 is connected in the forward direction and a second photovoltaic DC/DC unit that is turned on when the photovoltaic cell 10 is connected in the reverse direction;
and the switching module is respectively connected with the photovoltaic cell 10, the DC/AC controller 20, the first photovoltaic DC/DC unit and the second photovoltaic DC/DC unit, and is used for changing the conduction state of the switching module according to the wiring state of the photovoltaic cell 10, and further controlling the conduction of the first photovoltaic DC/DC unit or the second photovoltaic DC/DC unit.
The reverse connection self-adaptive control circuit of the embodiment adds a first photovoltaic DC/DC unit and a second photovoltaic DC/DC unit in the circuit structure of the power supply system of the existing photovoltaic air conditioner, the first photovoltaic DC/DC unit is in the conduction state when the photovoltaic cell 10 is in the forward connection, the second photovoltaic DC/DC unit is in the reverse connection state when the photovoltaic cell 10 is in the reverse connection, the switching module is used for changing the conduction state of the photovoltaic cell 10, and then the first photovoltaic DC/DC unit is controlled or the second photovoltaic DC/DC unit is in the conduction state, so that the connection relation between the photovoltaic cell and the DC/AC controller can be adjusted adaptively no matter whether the photovoltaic cell is in the forward connection or in the reverse connection, and the normal work of the power supply system is ensured without manual participation.
In practical applications, the DC/DC unit includes an inductor, a switch tube and a diode to form a first BOOST circuit (i.e. a first photovoltaic DC/DC unit), so as to implement a BOOST function, wherein the inductor and the diode are connected in series (the inductor is connected to the positive electrode of the diode), and are connected between the positive terminal of the photovoltaic cell and the positive terminal of the DC/AC controller, the drain of the switch tube is connected between the inductor and the diode, and the source of the switch tube is connected between the negative terminal of the photovoltaic cell and the negative terminal of the DC/AC controller, in the case of reverse connection of the photovoltaic cell, the positive terminal of the photovoltaic cell is actually the negative terminal, and the negative terminal is actually the positive terminal, so that the connection relationship between the positive and negative terminals of the photovoltaic cell and the inductor, the switch tube and the diode needs to be changed, and considering that the connection relationship cannot be easily changed once the structure is determined, a set of an inductor, a switch tube and a diode may be further provided, since the diode is not directly connected to the positive and negative terminals of the photovoltaic cell, so that the positive terminal of the photovoltaic cell and the diode can be repeatedly connected to the positive and negative terminals of the second BOOST circuit, respectively, so as to implement a second BOOST circuit, the BOOST circuit comprises: a first switch K1 having a first terminal connected to the positive terminal of the photovoltaic cell 10, a second terminal connected to the first terminal of the first photovoltaic DC/DC unit, and a third terminal connected to the second terminal of the second photovoltaic DC/DC unit; a second switch K2 having a first terminal connected to the negative terminal of the photovoltaic cell 10, a second terminal connected to a first terminal of a third switch K3, and a third terminal connected to a first terminal of the second photovoltaic DC/DC unit; a third switch K3, having a first terminal connected to the negative terminal Vbus "of the DC/AC controller 20, a second terminal connected to the second terminal of the first photovoltaic DC/DC unit, and a third terminal connected to the second terminal of the second photovoltaic DC/DC unit; 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 Vbus + of the DC/AC controller 20.
Above-mentioned first switch K1, second switch K2 and third switch K3 are the relay, first switch K1's first end is the stationary contact 0 of relay, the second end is the normally closed contact 1 of relay, the third end is the normally open contact 2 of relay, the same is true, second switch K2's first end is the stationary contact 0 of relay, the second end is the normally closed contact 1 of relay, the third end is the normally open contact 2 of relay, third switch K3's first end is the stationary contact 0 of relay, the second end is the normally closed contact 1 of relay, the third end is the normally open contact 2 of relay.
To form a BOOST voltage circuit, the first photovoltaic DC/DC unit comprises:
a first end of the first inductor L1 is connected to the second end of the first switch K1, and a second end of the first inductor L1 is connected to the first end of the first switch Q1; a second end of the first switch tube Q1 is connected with a second end of the third switch K3; a diode D1 has a positive electrode connected between the second end of the first inductor L1 and the first end of the first switching tube Q1, and a negative electrode connected to a positive electrode terminal Vbus + of the DC/AC controller 20.
The second photovoltaic DC/DC unit includes: a first end of the second inductor L2 is connected to the third end of the second switch K2, and a second end of the second inductor L2 is connected to the first end of the second switching tube Q2, the second end of the first inductor L1, and the first end of the first switching tube Q1, respectively; a second end of the second switch tube Q2 is connected to a third end of the first switch K1 and a third end of the third switch K3 respectively; the second photovoltaic DC/DC unit includes a diode D1. That is, in order to save devices, the first photovoltaic DC/DC unit and the second photovoltaic DC/DC unit share one diode.
If the photovoltaic cell is reversely connected, the output current of the photovoltaic cell is smaller than the current under the condition of positive connection, in order to collect the output current of the photovoltaic cell and further judge that the photovoltaic cell is reversely connected enough, the circuit further comprises: the sampling module 30 is connected with the current sensor U1, the current sensor U1 is arranged at 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 connection of the second switch K2, and is used for collecting the current output by the photovoltaic cell 10 and generating a sampling signal according to the current output by the photovoltaic cell 10.
Fig. 4 is a structural diagram of a sampling module according to an embodiment of the present invention, and as shown in fig. 4, the sampling module 30 includes: an operational amplifier A, the non-inverting input end of which is connected with the current sensor U1 and inputs U1_ Out, the inverting input end of which is input with the reference voltage U1_ Ref, and the output end of which is connected with the inverting input end of the operational amplifier A, and is also connected with a control module and used for outputting the sampling voltage V o 。
The current sensor may be a hall device, for example, when the photovoltaic cell is connected in the forward direction, U1_ Out outputs 2.5V, and U1 _refis set to 2.5V, and if Vref is set to 1.5V, the sampling voltage Vo =1.5V output by the sampling module 30, when the photovoltaic connection is connected in the reverse direction, the current output by the photovoltaic cell decreases, and the value of U1_ Out is smaller than the value of U1_ Ref, so that the value of the sampling voltage Vo is smaller than 1.5V, therefore, it can be determined whether the current output by the photovoltaic cell is smaller than a normal value by the value of the sampling voltage output by the sampling module 30, and further, whether the photovoltaic cell is connected in the reverse direction is determined.
As shown in fig. 3, the circuit further comprises: a control module 40 for generating a sampling voltage V according to the current sampling module 30 o And outputting a control signal to control the conduction state of the switching module.
In order to supply power to the sampling module 30 and the control module 40, as shown in fig. 3, the circuit further includes: and the input end of the auxiliary power supply 50 is connected with the power grid, and the output end of the auxiliary power supply is respectively connected with the sampling module 30 and the control module 40 and used for supplying power to the sampling module 30 and the control module 40.
To sum up, the reverse connection adaptive control circuit of this embodiment adds device second switch tube Q2, second inductance L2, first switch K1, second switch K2, third switch K3 on the basis of existing structure, and the photovoltaic DC/DC module in this embodiment is by first inductance L1, first switch tube Q1, diode D1, second inductance L2, second switch tube Q2 is constituteed, still includes the DC/AC controller between photovoltaic cell and the photovoltaic air conditioner, and the DC/AC controller still connects the electric wire netting, and above-mentioned reverse connection adaptive control circuit still includes: auxiliary power source 50, control module 40, and sampling module 30. The photovoltaic DC/DC is connected between the photovoltaic cell assembly and the direct-current bus, the bidirectional DC/AC controller is connected between the direct-current bus and a 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 current output by the photovoltaic cell, the control module 40 can output control signals S _ Q1, S _ Q2, S _ K1, S _ K2 and S _ K3, and the first switch tube Q1, the second switch tube Q2, the first switch K1, the second switch K2 and the third switch K3 of the controller are respectively switched on and switched off.
The specific working process of the reverse connection adaptive control circuit is as follows:
when the input terminal of the photovoltaic side is connected positively, the sampling module 30 can collect a current signal output by the photovoltaic cell, generate a sampling voltage Vo, and transmit the sampling voltage Vo to the control module 40, the control module 40 determines that the positive terminal and the negative terminal of the photovoltaic cell are connected positively according to the sampling voltage Vo, and then sends a control signal S _ Q1, so that the first switch tube Q1 is intermittently switched on and off according to a preset duty ratio, the photovoltaic cell is switched on to work normally, at the moment, the first switch K1, the second switch K2 and the third switch K3 are controlled to be switched off, the static contact 0 of the first switch K1, the second switch K2 and the third switch K3 is switched on with the normally closed contact 1, and a first photovoltaic DC/DC unit composed of the first inductor L1, the first switch Q1 and the diode D1 is controlled to be switched on and work normally.
When the positive terminal and the negative terminal of the photovoltaic cell are connected in a reverse connection mode, the sampling module 30 can collect a current signal output by the photovoltaic cell, generate a sampling voltage Vo and transmit the sampling voltage Vo to the control module 40, the control module 40 judges that the positive terminal and the negative terminal of the photovoltaic cell are connected in a reverse connection mode according to the sampling voltage Vo, then sends a control signal S _ K1/S _ K2/S _ K3 to control the first switch K1, the second switch K2 and the third switch K3 to be electrified, a static contact 0 and a normally open contact 2 of the first switch K1, the second switch K2 and the third switch K3 to be powered off are connected, and meanwhile the second switch tube Q2 is controlled to be intermittently connected and disconnected according to a preset duty ratio, so that a second photovoltaic DC/DC unit formed by the second inductor L2, the second switch tube Q2 and the diode D1 is connected and works normally.
When the photovoltaic cell is connected, the system can be kept to normally work no matter whether the anode and the cathode are reversely connected or not, manual intervention is not needed, and the problem of reverse connection of photovoltaic side engineering installation wiring is solved, so that the problem of system temperature rise aggravation caused by reverse connection of photovoltaic is solved.
Example 2
The embodiment provides a power supply system, which comprises a photovoltaic cell, a DC/AC controller and a reverse connection self-adaptive control circuit, wherein the reverse connection self-adaptive control circuit is used for ensuring that no matter the photovoltaic cell is in forward connection or reverse connection, the connection relation between the photovoltaic cell and the DC/AC controller can be adaptively adjusted, and then the normal work of the power supply system is ensured without manual participation.
Example 3
The embodiment provides a photovoltaic air conditioner, including the power supply system of above-mentioned embodiment for guarantee that no matter photovoltaic cell is just connecing or the transposition, all adaptivity ground adjusts the relation of connection of photovoltaic cell and DC AC controller, and then guarantees that power supply system normally works, need not artifical the participation, thereby guarantees whole photovoltaic air conditioner's normal operating.
Example 4
In this embodiment, a control method is provided, which is applied to the foregoing reverse connection adaptive control circuit, and fig. 5 is a flowchart of the control method according to the embodiment of the present invention, as shown in fig. 5, the control method includes:
and S101, after the photovoltaic cell is connected with the DC/AC controller, judging whether the photovoltaic cell is reversely connected.
S102, if not, the switching module is controlled to be in a first conduction state, so that the first photovoltaic DC/DC unit is controlled to be conducted, and the first switch tube in the first photovoltaic DC/DC unit is controlled to be switched on and off intermittently.
And S103, if yes, controlling the switching module to be in a second conduction state, further controlling the second photovoltaic DC/DC unit to be conducted, and controlling a second switching tube in the second photovoltaic DC/DC unit to be switched on and off intermittently.
According to the above, if the photovoltaic cell is connected reversely, the current output by the photovoltaic cell will be smaller than the current in the case of being connected, therefore, the determination of whether the photovoltaic cell is connected reversely includes: judging whether the current output by the photovoltaic cell is greater than a preset threshold value or not; if yes, judging that the photovoltaic cell is not reversely connected; and if not, judging that the photovoltaic cell is reversely connected.
In the control method of the embodiment, after the photovoltaic cell is connected with the DC/AC controller, whether the photovoltaic cell is reversely connected is determined. When the photovoltaic power generation system is reversely connected, the switching module is controlled to be in a second conduction state, so that the second photovoltaic DC/DC unit is controlled to be conducted, and the second switching tubes in the second photovoltaic DC/DC unit are controlled to be intermittently switched on and off; and when the photovoltaic power generation unit is in positive connection, the switching module is controlled to be in a first conduction state, so that the first photovoltaic DC/DC unit is controlled to be conducted, and the first switching tube in the first photovoltaic DC/DC unit is controlled to be intermittently switched on and off. The photovoltaic battery can be ensured to be connected in a positive or reverse mode, the connection relation between the photovoltaic battery and the DC/AC controller can be adjusted adaptively, and then the normal work of a power supply system is ensured without manual participation.
Specifically, judging whether the current output by the photovoltaic cell is greater than a preset threshold value includes: and judging whether the sampling voltage output by the sampling module is greater than a preset threshold value, if so, judging that the current output by the photovoltaic cell is greater than the preset threshold value, and if not, judging that the current output by the photovoltaic cell is less than or equal to the preset threshold value.
Fig. 6 is a flowchart of a control method according to another embodiment of the present invention, as shown in fig. 6, the control method includes the following preferred implementation steps:
s1, collecting current output by the photovoltaic cell.
Specifically, the current output by the photovoltaic cell is collected by the sampling module 30, the sampling module 30 is connected to the current sensor U1, and the current sensor U1 is disposed at 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 connection of the second switch K2, and is used for connecting the second inductor L1, the second inductor L2, the first switch K1, and the second switch K2The method for sampling the current output by the photovoltaic cell 10 and generating the sampling signal according to the current output by the photovoltaic cell 10 includes: an operational amplifier A, the non-inverting input end of which is connected with the current sensor U1 and inputs U1_ Out, the inverting input end of which is input with the reference voltage U1_ Ref, the output end of which is connected with the inverting input end of the operational amplifier A, and the operational amplifier A is also connected with the control module and is used for outputting the sampling voltage V o . The current sensor may be a hall device, for example, when the photovoltaic cell is connected in the forward direction, U1_ Out outputs 2.5V, and U1 _refis set to 2.5V, and if Vref is set to 1.5V, the sampling voltage Vo =1.5V output by the sampling module 30, when the photovoltaic connection is connected in the reverse direction, the current output by the photovoltaic cell decreases, and the value of U1_ Out is smaller than the value of U1_ Ref, so that the value of the sampling voltage Vo is smaller than 1.5V, therefore, it can be determined whether the current output by the photovoltaic cell is smaller than a normal value by the value of the sampling voltage output by the sampling module 30, and further, whether the photovoltaic cell is connected in the reverse direction is determined.
And S2, judging whether the current output by the photovoltaic cell is larger than a preset threshold value, if so, executing the step S3, and if not, executing the step S4.
And S3, judging that the photovoltaic cell is connected positively, controlling the first switch K1, the second switch K2 and the third switch K3 to be powered off, switching on a static contact 0 and a normally closed contact 1 of the first switch K1, the second switch K2 and the third switch K3 which are powered off, further controlling a first photovoltaic DC/DC unit consisting of the first switch tube Q1, the first inductor L1 and the diode D1 to be switched on, and simultaneously controlling the first switch tube Q1 to be intermittently switched on and off according to a preset duty ratio.
And S4, judging that the photovoltaic cell is in positive and negative connection, controlling the first switch K1, the second switch K2 and the third switch K3 to be powered off, switching on the static contact 0 and the normally open contact 2 of the first switch K1, the second switch K2 and the third switch K3 which are powered off, further controlling the first photovoltaic DC/DC unit consisting of the second switch tube Q2, the second inductor L2 and the diode D1 to be switched on, and simultaneously controlling the second switch Q2 to be intermittently switched on and off according to a preset duty ratio.
Example 5
The present embodiment provides a computer-readable storage medium on which a computer program is stored, which when executed by a processor implements the control method of the above-described embodiment.
The above-described circuit embodiments are merely illustrative, wherein the modules described as separate parts may or may not be physically separate, and the parts shown as modules may or may not be physical modules, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (13)

1. A reverse connection adaptive control circuit disposed between a photovoltaic cell and a DC/AC controller, the circuit comprising:
a photovoltaic DC/DC module including a first photovoltaic DC/DC unit that conducts when the photovoltaic cell is connected in the forward direction and a second photovoltaic DC/DC unit that conducts when the photovoltaic cell is connected in the reverse direction;
and the switching module is respectively connected with the photovoltaic battery, the DC/AC controller, the first photovoltaic DC/DC unit and the second photovoltaic DC/DC unit and is used for changing the conduction state of the switching module according to the wiring state of the photovoltaic battery so as to control the conduction of the first photovoltaic DC/DC unit or the second photovoltaic DC/DC unit.
2. The circuit of claim 1, wherein the switching module comprises:
a first switch having a first terminal connected to the positive terminal of the photovoltaic cell, a second terminal connected to the first terminal of the first photovoltaic DC/DC unit, and a third terminal connected to the second terminal of the second photovoltaic DC/DC unit;
a second switch having a first terminal connected to the negative terminal of the photovoltaic cell, a second terminal connected to a first terminal of a third switch, and a third terminal connected to a first terminal of the second photovoltaic DC/DC unit;
the first end of the third switch is also connected with the negative terminal of the DC/AC controller, the second end of the third switch is connected with the second end of the first photovoltaic DC/DC unit, and the third end of the third switch is connected with the second end of the second photovoltaic DC/DC unit;
the third terminal of the first photovoltaic DC/DC unit and the third terminal of the second photovoltaic DC/DC unit are connected with the positive terminal of the DC/AC controller.
3. The circuit of claim 2, wherein the first photovoltaic DC/DC unit comprises:
a first end of the first inductor is connected with a second end of the first switch, and a second end of the first inductor is connected with a first end of the first switch tube;
the second end of the first switch tube is connected with the second end of the third switch;
and the anode of the diode is connected between the second end of the first inductor and the first end of the first switching tube, and the cathode of the diode is connected with the anode terminal of the DC/AC controller.
4. The circuit of claim 3, wherein the second photovoltaic DC/DC unit comprises:
a first end of the second inductor is connected with a third end of the second switch, and a second end of the second inductor is connected with a first end of a second switch tube, a second end of the first inductor and a first end of the first switch tube respectively;
a second end of the second switch tube is connected with a third end of the first switch and a third end of the third switch respectively;
the second photovoltaic DC/DC unit includes the diode.
5. The circuit of claim 4, further comprising:
the sampling module is connected with a current sensor, the current sensor is arranged at the second end of the first inductor, the second end of the second inductor, the first end of the first switch and the joint of the second switch and used for collecting the current output by the photovoltaic cell and generating a sampling signal according to the current output by the photovoltaic cell.
6. The circuit of claim 5, wherein the sampling module comprises:
and the non-inverting input end of the operational amplifier is connected with the current sensor, the inverting input end of the operational amplifier inputs reference voltage, and the output end of the operational amplifier is connected with the inverting input end of the operational amplifier and is also connected with the control module.
7. The circuit of claim 5, further comprising:
and the control module is used for outputting a control signal according to the sampling signal generated by the current sampling module so as to control the conduction state of the switching module and the on-off of the first switch tube and the second switch tube.
8. The circuit of claim 7, further comprising:
and the input end of the auxiliary power supply is connected with a power grid, and the output end of the auxiliary power supply is respectively connected with the sampling module and the control module and is used for supplying power to the sampling module and the control module.
9. A power supply system comprising a photovoltaic cell and a DC/AC controller, further comprising the reverse-connection adaptive control circuit of any one of claims 1 to 8.
10. A photovoltaic air conditioner characterized by comprising the power supply system of claim 9.
11. A control method applied to the reverse connection adaptive control circuit according to any one of claims 1 to 8, characterized by comprising:
after the photovoltaic cell is connected with the DC/AC controller, judging whether the photovoltaic cell is reversely connected;
if not, the switching module is controlled to be in a first conduction state, so that the first photovoltaic DC/DC unit is controlled to be conducted, and the first switch tube in the first photovoltaic DC/DC unit is controlled to be intermittently switched on and off;
if yes, the switching module is controlled to be in a second conduction state, the second photovoltaic DC/DC unit is further controlled to be conducted, and the second switch tube in the second photovoltaic DC/DC unit is controlled to be switched on and off intermittently.
12. The control method of claim 11, wherein determining whether the photovoltaic cells are reverse connected comprises:
judging whether the current output by the photovoltaic cell is greater than a preset threshold value or not;
if yes, judging that the photovoltaic cells are not reversely connected;
and if not, judging that the photovoltaic cell is reversely connected.
13. A computer-readable storage medium on which a computer program is stored, characterized in that the program, when executed by a processor, implements the control method according to claim 11 or 12.
CN202211072248.XA 2022-09-02 2022-09-02 Reverse connection self-adaptive control circuit, control method, power supply system and photovoltaic air conditioner Pending CN115276188A (en)

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CN202211072248.XA CN115276188A (en) 2022-09-02 2022-09-02 Reverse connection self-adaptive control circuit, control method, power supply system and photovoltaic air conditioner

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Application Number Priority Date Filing Date Title
CN202211072248.XA CN115276188A (en) 2022-09-02 2022-09-02 Reverse connection self-adaptive control circuit, control method, power supply system and photovoltaic air conditioner

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CN115276188A true CN115276188A (en) 2022-11-01

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