CN108418543B

CN108418543B - Energy optimization system and data communication method thereof

Info

Publication number: CN108418543B
Application number: CN201710072645.XA
Authority: CN
Inventors: 张永
Original assignee: Fonrich Shanghai New Energy Technology Co ltd
Current assignee: Fonrich Shanghai New Energy Technology Co ltd
Priority date: 2017-02-10
Filing date: 2017-02-10
Publication date: 2020-12-29
Anticipated expiration: 2037-02-10
Also published as: CN108418543A

Abstract

The invention mainly relates to an energy optimization system and a data communication method thereof.A voltage conversion circuit configured by a photovoltaic cell and used for executing maximum power tracking is arranged, a first input end and a second input end of the voltage conversion circuit are connected to the positive electrode and the negative electrode of a corresponding photovoltaic cell, and the voltage provided by the photovoltaic cell after power optimization is carried out is output at the first output end and the second output end of the voltage conversion circuit. The invention mainly relates to the technical field of photovoltaic power generation, in particular to a scheme that power optimization circuits are used in photovoltaic modules, and the power optimization circuits can send data outwards in a power carrier signal mode, so that the maximization of the output power of the whole photovoltaic module is ensured, and the communication function of sending the data is realized.

Description

Energy optimization system and data communication method thereof

Technical Field

The invention mainly relates to the technical field of photovoltaic power generation, in particular to a scheme that power optimization circuits are used in photovoltaic modules, and the power optimization circuits can send data outwards in a power carrier signal mode, so that the maximization of the output power of the whole photovoltaic module is ensured, and the communication function of sending the data is realized.

Background

Along with the industrialization process of some developing countries such as China, extremely severe environments such as haze and the like frequently appear, and countries all over the world generally recognize that: the search for an inexhaustible and cyclic renewable energy to replace the traditional chemical energy which has limited resources and pollutes the environment becomes an important proposition which is urgently needed to be solved at present. The technological development based on new technology and new material makes the renewable energy resource developed and utilized modernized, such as solar energy, geothermal energy, wind energy, ocean energy, biomass energy, nuclear fusion energy, etc. and the new energy resource developed in environment protection and persistence is applied more and more widely. Because the new energy of photovoltaic power generation has the advantages of cleanness, safety, reliability, low operation cost, simple daily maintenance, availability at any place and the like, the photovoltaic power generation system becomes a novel industry which is generally concerned and intensively developed by countries in the world, and plays an indispensable role in solving the problems of energy shortage and power utilization in remote areas. The core of the photovoltaic power generation technology is a photovoltaic cell panel, distributed or large-scale power stations adopt extremely large cell panel arrays, other portable or non-portable electronic devices need to frequently interact information with the cell panel, and in consideration of the number of the cell panel, a reasonable communication mechanism must be established, parameter data of the cell panel can be acquired from the cell panel through the communication mechanism, so that the pressure of data acquisition on the spot is reduced, and accurate data acquisition is achieved.

At present, various intelligent control systems, such as a wireless meter reading system, an access control system, an anti-theft alarm system, a safety fire prevention system and the like in an intelligent community, an industrial data acquisition system, a hydrological meteorological control system, a robot control system, a digital image transmission system and the like, can not transmit data information. It CAN be said that the data information transmission system is an important component of various intelligent control systems, and the data transmission mode mostly adopts a wired data transmission mode, such as parallel transmission, serial transmission, CAN bus and other various protocols, etc., in which the transmission carrier of data is twisted pair, coaxial cable or optical fiber. However, in a monitoring system using a single chip microcomputer or a similar processor, data acquisition devices in many application occasions are installed in the field or the wild with severe environmental conditions, and most photovoltaic power stations are built in the waters or the desert areas in the suburbs. In particular: the collected data is transmitted to the handheld terminal in a communication mode, and then the data is transmitted to the background computer equipment through the handheld terminal to be analyzed and processed. Therefore, data transmission between the data acquisition device and the handheld terminal needs to solve the communication problem, and the adoption of a wired data transmission mode is obviously not suitable, for example, the number of the photovoltaic power station battery panel arrays is staggering. Considering that data transmission can be carried out in a wireless mode, namely data transmission is realized through air or vacuum, compared with the traditional wired data transmission, the wireless data transmission mode can be used without considering the installation problem of a transmission cable, so that a large number of wires and cables and labor are saved, the construction difficulty and the construction cost are reduced, and the wireless data transmission mode is a research subject with development potential. However, the disadvantage of wireless communication is also obvious, and the shortest transmission distance is the largest short place, and we will consider the carrier wave in the following.

In order to ensure that the whole power generation system can run more safely and reliably, various potential threats can be preferably found in time, for example, a hot spot effect caused by shadow shielding is a negative threat, and some batteries may be converted from a power supply to a load to cause a battery panel to be heated to be burnt, so that monitoring of working parameters such as voltage, current, power, temperature and the like of the photovoltaic batteries is an important link in the photovoltaic power generation system. The working parameter monitoring of the photovoltaic cell adopts a power line carrier as a communication means in practical application occasions, the parameters of the photovoltaic cell can be easily transmitted to a power line which provides photovoltaic voltage by the photovoltaic cell as communication data by means of the power line carrier, and then the real-time parameters of the photovoltaic cell can be acquired by decoding a carrier signal from the power line. Unlike a common data communication line, which originally aims at transmitting power rather than data, a power line is not ideal for data communication, and is a very unstable transmission channel, which is characterized by significant noise and severe signal attenuation. In order to overcome the problem of instability, the power line broadband carrier technology adopts modulation technologies such as spread spectrum and orthogonal frequency division multiplexing, and the fact proves that the multi-carrier orthogonal frequency division multiplexing is an effective method for solving the problem of transmission interference on a power line so far, and the power line broadband communication adopts the orthogonal frequency division multiplexing technology to effectively resist multipath interference so that interfered signals can still be reliably received. The method for improving the reliability of the signal by sampling the voltage level of the photovoltaic cell and the carrier is only one aspect, but in the case of simultaneous application of the photovoltaic cell and the carrier, since the voltage level of the photovoltaic cell itself is greatly changed by the ambient temperature and the light radiation intensity, the distortion of the carrier signal itself propagation on the power line and the characteristic of the cell that the output characteristic is easy to fluctuate are mixed together, so that the actual carrier signal expected to be captured by the receiving end is not accurate, the error rate is high, and the voltage superposed on the photovoltaic cell string group is also interfered by the carrier, so that the actual voltage on the whole string group may not be within the expected range. We will consider in the following the use of carrier signals to transmit operating parameters such as voltage, current, power and temperature of photovoltaic cells.

Disclosure of Invention

The invention discloses an energy optimization system for power optimization of photovoltaic cells, comprising:

the photovoltaic cell is provided with a voltage conversion circuit which executes maximum power tracking, a first input end and a second input end of the voltage conversion circuit are connected to the positive electrode and the negative electrode of the corresponding photovoltaic cell, and the voltage provided by the photovoltaic cell after power optimization is carried out is output at a first output end and a second output end of the voltage conversion circuit;

wherein: the voltage conversion circuit is connected with a switch tube and a first inductor in series between a second input end and a second output end, connected with a second inductor between the first input end and the first output end, connected with a diode between the interconnection node between the switch tube and the first inductor and the first input end, and connected with a first capacitor between the second output end and the first input end.

In the energy optimization system, a plurality of photovoltaic cells are connected in series to form a battery string, and the voltage output by the voltage conversion circuit corresponding to each photovoltaic cell represents the actual voltage provided by the photovoltaic cell on the battery string; wherein: the mode of connecting the multi-stage photovoltaic cells to the corresponding multi-stage voltage conversion circuits in series is as follows: the second output terminal of any previous stage voltage conversion circuit is connected to the first output terminal of the voltage conversion circuit of the next subsequent stage via a serial connection line.

In the energy optimization system, the voltage conversion circuit configured by any one stage of photovoltaic cell is also provided with a processor and a carrier sending module; wherein: and the working parameters (data) of any one stage of photovoltaic cell are transmitted to the serial connection line by a processor which is arranged on the voltage conversion circuit corresponding to the photovoltaic cell through a carrier which is generated by a driving carrier transmitting module.

In the energy optimization system, the carrier sending module configured in each stage of the voltage conversion circuit includes a branch circuit including a first resistor, a bypass capacitor and a switch element, which is connected in series between the first output terminal and the second input terminal, and a second resistor connected in parallel to two ends of the bypass capacitor is further disposed in the branch circuit.

In the energy optimization system, the first and second types of multi-stage voltage conversion circuits are defined in the whole multi-stage voltage conversion circuit; assuming that the photovoltaic cell PV _ K +1 corresponds to the first type of voltage conversion circuit CV _ K +1, and assuming that the photovoltaic cell PV _ K corresponds to the second type of voltage conversion circuit CV _ K; a carrier signal transmitted by the carrier transmission module SIG of the first type voltage conversion circuit CV _ K +1 needs to be propagated through a path between the first output terminal N1_ K and the second output terminal N2_ K of the second type voltage conversion circuit CV _ K; and the path of such a path is: from one of the first and second output terminals (N1 _ K, N2_ K) of the second type of voltage converting circuit CV _ K, the carrier signal propagates to the first capacitor C1 of the second type of voltage converting circuit CV _ K, after which the carrier signal further propagates to the other of the first and second output terminals (N1 _ K, N2_ K) via the first capacitor C1.

In the energy optimization system, a second capacitor may be connected between the first input terminal and the second input terminal of the voltage conversion circuit.

In the energy optimization system, a compensation capacitor and a control switch are connected in series between the first output end and the second input end, the processor drives the control switch to be turned off when the processor drives the carrier sending module to send the carrier signal to the serial connection line, and the processor drives the control switch to be turned on only when the carrier sending module does not send the carrier signal.

In the energy optimization system, a compensation capacitor and a control switch are connected in series between the first output end and the second output end, the processor drives the control switch to be turned off when the processor drives the carrier sending module to send the carrier signal to the series connection line, and the processor drives the control switch to be turned on only when the carrier sending module does not send the carrier signal.

In the energy optimization system, the carrier sending module configured in each stage of the voltage conversion circuit includes a branch circuit including a first resistor, a bypass capacitor and a switch element, which is connected in series between the second output terminal and the second input terminal, and a second resistor connected in parallel to two ends of the bypass capacitor is further disposed in the branch circuit.

In the energy optimization system, a compensation capacitor and a control switch are connected in series between the second output end and the second input end, the processor drives the control switch to be turned off when the processor drives the carrier sending module to send the carrier signal to the serial connection line, and the processor drives the control switch to be turned on only when the carrier sending module does not send the carrier signal.

The invention also discloses a data communication method based on the energy optimization system, wherein a battery pack string is formed by connecting the multi-stage photovoltaic cells PV _1 to PV _ N in series, and the multi-stage voltage conversion circuits CV _1 to CV _ N corresponding to the multi-stage photovoltaic cells PV _1 to PV _ N in series are set as follows: the second output end N2_ K of any previous stage voltage conversion circuit CV _ K is connected to the first output end N1_ K +1 of the voltage conversion circuit CV _ K +1 of the next stage through the serial connection lines LANC; each level of voltage conversion circuit is also provided with a processor and a carrier sending module;

the data communication method performed by the voltage conversion circuit of any stage includes: one path of driving signal output by the processor in the voltage conversion circuit of any stage is used for driving a switch element in the carrier sending module, so that the carrier sending module injects the carrier signal from the first output end of the voltage conversion circuit of any stage to the serial line;

the driving signal for driving the switching element in the carrier transmitting module takes the negative electrode of the first-stage photovoltaic cell corresponding to the voltage conversion circuit of any stage as a reference ground potential. As is known to those skilled in the art, the high level and the low level of the driving signal are defined as being divided into a high level and a low level with respect to a certain reference potential, and in this embodiment, the high level or the low level of the driving signal is defined by using the negative electrode of the photovoltaic cell as a reference ground or a virtual ground GND-1 as a reference voltage, which has an advantage of simple driving.

In the method, the carrier sending module configured in each stage of the voltage conversion circuit comprises a branch circuit which is connected in series between a first output end and a second input end and comprises a first resistor, a bypass capacitor and a switch element, and a second resistor which is connected in parallel at two ends of the bypass capacitor is also arranged in the branch circuit;

wherein: a first resistor and a bypass capacitor are provided between a first terminal (e.g., a drain terminal of an NMOS) of the switching element and a first output terminal of the voltage conversion circuit, and a second terminal (e.g., a source terminal of an NMOS) of the switching element is connected to a negative electrode of the primary photovoltaic cell corresponding to the voltage conversion circuit.

In the above method, the first and second types of voltage conversion circuits are defined in the entire multi-stage voltage conversion circuits CV _1 to CV _ N, assuming that the first type of voltage conversion circuit CV _ K +1 corresponds to the photovoltaic cell PV _ K +1, and assuming that the second type of voltage conversion circuit CV _ K corresponds to the photovoltaic cell PV _ K; the carrier signal transmitted by the carrier transmission module SIG of the first type voltage conversion circuit CV _ K +1 is propagated from a path between the first output terminal N1_ K and the second output terminal N2_ K of the second type voltage conversion circuit CV _ K; and the path paths in this embodiment are: from one of the first and second output terminals (N1 _ K, N2_ K) of the second type of voltage converting circuit CV _ K, the carrier signal propagates to the first capacitor C1 of the second type of voltage converting circuit CV _ K, and then propagates to the other of the first and second output terminals (N1 _ K, N2_ K) via the first capacitor C1.

In the method, a compensation capacitor and a control switch are connected in series between the first output end and the second input end, the processor drives the control switch to be turned off at a stage of driving the carrier sending module to send the carrier signal to the serial connection line, and the processor drives the control switch to be turned on only at a stage of not sending the carrier signal by the carrier sending module.

In the method, a compensation capacitor and a control switch are connected in series between the first output end and the second output end, the processor drives the control switch to be turned off at a stage of driving the carrier sending module to send the carrier signal to the serial connection line, and the processor drives the control switch to be turned on only at a stage of not sending the carrier signal by the carrier sending module.

The invention also discloses a data communication method based on the energy optimization system, wherein a battery pack string is formed by connecting the multi-stage photovoltaic cells in series, and the mode of connecting the multi-stage voltage conversion circuits corresponding to the multi-stage photovoltaic cells in series is as follows: the second output end of any previous-stage voltage conversion circuit is connected to the first output end of the adjacent next-stage voltage conversion circuit through a serial connection wire; each level of voltage conversion circuit is also provided with a processor and a carrier sending module;

the data communication method performed by the voltage conversion circuit of any stage includes: one path of driving signal output by the processor in the voltage conversion circuit of any stage is used for driving a switch element in the carrier sending module, so that the carrier sending module injects the carrier signal from the second output end of the voltage conversion circuit of any stage to the serial line;

the driving signal for driving the switching element in the carrier transmitting module takes the negative electrode of the first-stage photovoltaic cell corresponding to the voltage conversion circuit of any stage as a reference ground potential.

In the method, the carrier sending module configured in each stage of the voltage conversion circuit comprises a branch circuit which is connected in series between the second output end and the second input end and comprises a first resistor, a bypass capacitor and a switch element, and a second resistor which is connected in parallel at two ends of the bypass capacitor is also arranged in the branch circuit;

wherein: a first resistor and a bypass capacitor are arranged between the first end of the switching element and the second output end of the voltage conversion circuit, and the second end of the switching element is connected to the negative electrode of the primary photovoltaic cell corresponding to the voltage conversion circuit.

In the method, the first and second voltage conversion circuits are defined in the whole multi-stage voltage conversion circuit; the carrier signal sent by the carrier sending module of the first class voltage conversion circuit needs to be propagated from a path between a first output end and a second output end of the second class voltage conversion circuit, and the path is as follows: propagating from one of the first and second output terminals of the second class of voltage converting circuit to the first capacitance of the second class of voltage converting circuit to the other of the first and second output terminals.

In the method, a compensation capacitor and a control switch are connected in series between the second output end and the second input end, the processor drives the control switch to be turned off at a stage of driving the carrier sending module to send the carrier signal to the serial connection line, and the processor drives the control switch to be turned on only at a stage of not sending the carrier signal by the carrier sending module.

Drawings

The features and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the following drawings:

fig. 1 is an exemplary schematic diagram of photovoltaic cells forming a battery string through a matched optimization circuit.

Fig. 2 is a schematic diagram of a first optimized topology of an energy optimization system setting carrier transmission module.

Fig. 3 is a schematic diagram of a second optimized topology of an energy optimization system configured with a carrier transmission module.

Fig. 4 is a first example of setting the compensation capacitor and the control switch based on the second optimized topology.

Fig. 5 is a second example of setting the compensation capacitor and the control switch based on a second optimized topology.

Fig. 6 is a first example of setting the compensation capacitor and the control switch based on a first optimized topology.

Fig. 7 is a second example of setting the compensation capacitor and the control switch based on the first optimized topology.

Detailed Description

The present invention will be described more fully hereinafter with reference to the accompanying examples, which are intended to illustrate and not to limit the invention, but to cover all those embodiments, which may be learned by those skilled in the art without undue experimentation.

Referring to fig. 1, a photovoltaic module array is the basis of the conversion of light energy into electric energy of a photovoltaic power generation system, and fig. 1 shows a basic battery string 101 installed in the photovoltaic module array, and each battery string 101 is formed by serially connecting a plurality of photovoltaic modules PV _1 and PV _2 … … PV modules PV _ N connected in series. In the present application, each PV module or PV cell PV is configured with a power optimization circuit for performing maximum power tracking MPPT, for example, a photovoltaic voltage generated by a first PV module PV _1 is voltage-converted by a first power optimization circuit CV _1 to perform power optimization, a photovoltaic voltage generated by a second PV module CV _2 is voltage-converted by a second power optimization circuit CV _2, until a photovoltaic voltage generated by an nth PV module PV _ N is voltage-converted by an nth power optimization circuit CV _ N to perform power optimization, where N is a natural number. It is supposed that the voltage output by the power optimization circuit CV corresponding to each photovoltaic cell PV can represent the actual voltage provided by the photovoltaic cell PV on the photovoltaic cell string 101, and we first assume that the photovoltaic cell string 101 of any string is connected in series with the first stage photovoltaic module PV _1, the second stage photovoltaic module PV _1 … … to the nth stage photovoltaic module PV _ N, and the first stage power optimization circuit CV _1 is used for performing maximum power tracking on the photovoltaic voltage source of the first stage photovoltaic cell PV _1 to perform voltage conversion and output V _ N₁Until the Nth-stage power optimization circuit CV _ N performs maximum power tracking on the photovoltaic voltage source of the Nth-stage photovoltaic cell PV _ N to perform voltage conversion and output V_NCan learn any string of photovoltaic battery packsThe total string level voltage on string 101 equals: the voltage V output by the first stage power optimization circuit CV _1₁Plus the voltage V output by the second stage power optimization circuit CV _2₂And the voltage V output by the third-stage power optimization circuit CV _3₃… … until the voltage V is added to the output of the Nth stage power optimization circuit CV _ N_NThe operation result of the cascade voltage is equal to V₁+ V₂+……V_N. The power optimization circuit or voltage conversion circuit CV, which is basically a DC-DC converter, will be described in detail below. It should be emphasized that any solution for maximum power tracking of a photovoltaic cell disclosed in the prior art is also applicable to the voltage converting circuit of the present application, and the detailed description of how the voltage converting circuit performs maximum power tracking MPPT is omitted. In fig. 1, the first-stage power optimization circuit CV _1, the second-stage power optimization circuit CV _2, through the nth-stage power optimization circuit CV _ N, and the like are connected in series through a series connection line LANC, and the cascade voltage superposed on the transmission series connection line LANC is transmitted to electric power equipment such as a combiner box or an inverter 170, and is combined and inverted and then is connected to alternating current. In fig. 1, a plurality of battery strings 101 are connected in parallel, and different battery strings 101 are connected in parallel to provide a dc voltage source.

Referring to fig. 2, the description is given by taking as an example a voltage conversion circuit CV _ K performing maximum power tracking configured by photovoltaic cells PV _ K (the natural number K ≦ N is assumed in the context). The first input end NX1 and the second input end NX2 of the voltage conversion circuit CV _ K are connected to the positive and negative poles of the corresponding photovoltaic cell PV _ K: in particular, the first input terminal NX1 is connected to the positive pole of the photovoltaic cell PV _ K and the second input terminal NX2 is connected to the negative pole of the photovoltaic cell PV _ K. The actual voltage provided by the photovoltaic cell PV _ K after power optimization MPPT is output between the first output terminal N1_ K and the second output terminal N2_ K of the voltage conversion circuit CV _ K. The voltage conversion circuit CV _ K has a switching tube S1 and a first inductor L1 connected in series between the second input terminal NX2 and the second output terminal N2_ K, and also has a second inductor L2 connected between the first input terminal NX1 and the first output terminal N1_ K. In addition to this, also in the voltage conversionA diode D is connected between the interconnection node NX3 of the interconnection between the switching tube S1 of the circuit CV _ K and the first inductor L1 and said first input terminal NX1, and a first capacitor C1 is also connected between the second output terminal N2_ K and its first input terminal NX1, wherein the anode of the diode D is connected to the interconnection node NX3 and the cathode is connected to the first input terminal NX 1. MPPT basic principle of the voltage conversion circuit of fig. 2: a first input end NX1 and a second input end NX2 of the voltage conversion circuit CV _ K extract a direct-current photovoltaic voltage source from between an anode and a cathode of the photovoltaic cell PV _ K, and a pulse width modulation signal PWM generated by the processor 100 operating MPPT calculation is coupled and transmitted to a gate control end of the switching tube S1, during a switching period of driving the switching tube S1 by implementing MPPT, the switching tube S1 needs to be turned on, and after the switching tube S1 is driven to be turned on by the PWM modulation signal, the current of the inductor L1 is increased; the modulation signal PWM will drive the switch tube S1 to turn off and freewheel through the diode D, the current of the inductor L1 decreases and begins to release energy and become the capacitor C₁And charging is carried out. It should be noted that, implementing Maximum Power Tracking Maximum Power Point Tracking on a DC/DC to DC conversion circuit in the boundary is a mature technology, for example, common Maximum Power Tracking includes a constant voltage method, a conductance increment method, a disturbance observation method, etc., which is not separately described in detail in this application, and any existing Maximum Power Tracking technology is applicable to the DC/DC voltage conversion circuit of this application.

Referring to fig. 2, a battery string 101 is formed by connecting multiple photovoltaic cells PV _1 to PV _ N in series, wherein only the photovoltaic cells PV _ K and PV _ K +1 adjacent to each other in the front and back are taken as an example for explanation. In particular, the voltage output by the voltage conversion circuit CV _ K corresponding to the photovoltaic cell PV _ K characterizes the actual voltage V that the photovoltaic cell PV _ K provides on said battery string_K. The voltage output by the voltage conversion circuit CV _ K +1 corresponding to the photovoltaic cell PV _ K +1 characterizes the actual voltage V provided by the photovoltaic cell PV _ K +1 on the battery string_K+1. A manner in which the multistage voltage conversion circuits CV _1 to CV _ N corresponding to the multistage photovoltaic cells PV _1 to PV _ N are connected in series: the second output end of any previous stage voltage conversion circuit is connected to the voltage of the adjacent next stage through a series connection wireA first output terminal of the conversion circuit. For example, the second output terminal N2_ K of any previous stage voltage conversion circuit CV _ K is connected to the first output terminal N1_ K +1 of the adjacent next stage voltage conversion circuit CV _ K +1 through the serial connection line LANC; or else it can be said that: the second output terminal N2_ K-1 of any previous stage voltage conversion circuit CV _ K-1 is connected to the first output terminal N1_ K of the adjacent subsequent stage voltage conversion circuit CV _ K through a serial connection line or a transmission line LANC. Thus, in this way, the multi-stage photovoltaic cells PV _1 to PV _ N are connected in series to form the battery string 101, and after the series connection, a reasonable string-stage voltage V can be provided between the first output terminal N1_1 of the first-stage voltage conversion circuit CV _1 and the second output terminal N2_2 of the last nth-stage voltage conversion circuit CV _ N₁+ V₂+……V_N。

Referring to fig. 2, partial data (working parameters) of the photovoltaic cell PV _ K or the photovoltaic cell PV _ K +1 needs to be detected and monitored in time, which are common working parameters such as voltage, current, power, and temperature, but the cell panel is generally located outdoors or even in a very remote place, some large power stations may also be located in places with good illumination radiation such as desert, saline-alkali land, or water area, the near field of the photovoltaic cell at the receiving end may transmit data in a wireless communication manner, and if the device receiving the data is far away from the photovoltaic cell, it is difficult to adopt a wireless manner. In order to realize data monitoring, a data transceiving communication function is necessary. The processor 100 and the carrier transmitting module SIG are further disposed in the voltage converting circuit CV _ K configured for any one stage of the photovoltaic cell PV _ K, the processor 100 itself may be sometimes attached with some detecting modules, such as a voltage detecting module, a current detecting module, a temperature detecting module, and the like of the photovoltaic cell, and at this time, the detecting modules do not need to be externally disposed, but if the processor 100 does not have the detecting modules, the detecting modules known in the art, such as voltage, current, power, and temperature, and the like, may also be used to detect the operating parameters of the photovoltaic cell and transmit the operating parameters to the processor 100, and then the processor 100 tries to transmit the data and the parameters (carrier, wireless, and the like). Processor 100 in fig. 2, in which operating parameters of any stage of photovoltaic cell PV _ K are carried by voltage conversion circuit CV _ K corresponding to the operating parametersThe carrier transmitting module SIG configured by the driving voltage converting circuit CV _ K is transmitted to the serial line LANC, the data is transmitted in a carrier signal manner, and of course, the operating parameters of the photovoltaic cell PV _ K +1 are also transmitted to the same transmission serial line LANC by the processor 100 provided in the voltage converting circuit CV _ K +1 corresponding to the operating parameters through the carrier transmitting module SIG configured by the driving voltage converting circuit CV _ K + 1. The details of how the carrier transmitting module SIG loads/transmits data to the serial line LANC in the form of a carrier signal will be described later. First, we should understand the topology structure of the carrier transmitting module/unit SIG, in which the carrier transmitting module configured in each stage of the voltage converting circuit includes a branch circuit having a first resistor, a bypass capacitor and a switching element, connected in series between a first output terminal and a second input terminal, and a second resistor connected in parallel to two ends of the bypass capacitor is further disposed in the branch circuit. The voltage conversion circuit CV _ K is taken as an example to illustrate, and the carrier transmission module SIG is configured to include a first resistor R1 and a bypass capacitor C connected in series between the first output terminal N1_ K and the second input terminal NX2 of the voltage conversion circuit CV _ K_BCAnd a branch of a switching element S2, which is also provided with a bypass capacitor C connected in parallel_BCA second resistor R2 across. In addition, taking the voltage conversion circuit CV _ K +1 as an example, the carrier transmitting module SIG includes a first resistor R1 and a bypass capacitor C connected in series between the first output terminal N1_ K +1 and the second input terminal NX2 of the voltage conversion circuit CV _ K +1_BCAnd a branch of a switching element S2, which is also provided with a bypass capacitor C connected in parallel_BCA second resistor R2 across. As for the working mechanism of the carrier transmission module SIG for transmitting the carrier signal, the voltage conversion circuit CV _ K is explained as follows: the driver signal DRI from the processor 100 configured with the voltage conversion circuit CV _ K drives the switching element S2 to switch between on and off, the branch having a current flowing when the switching element S2 is turned on and having no current flowing when the switching element S2 is turned off, so that the branch actively introduces a disturbing signal between the first output terminal N1_ K and the second input terminal NX2 due to the off/on driving of the switching element S2 by the driver signal DRI, the disturbing signal being a signal which actively introduces a disturbing signal between the first output terminal N1_ K and the second input terminal NX2The frequency is determined entirely by the driving signal DRI, and the disturbing signal is injected directly from the first output terminal N1_ K onto said serial line LANC. We consider as a power carrier signal a disturbance signal generated by a branch (carrier transmit module SIG) resulting from such a change in current that is produced by the branch off current being cut off and the branch on. The above is mainly considered from the point of view of the station transmitting the carrier signal, if the station is considered from the point of view of receiving the carrier signal, decoding/decoding of the carrier signal can be achieved on those connecting/concatenation lines LANC shown in fig. 1 by means of currently any carrier decoding module belonging to the known art. After the processor 100 sends data (e.g., designated operating parameters of the battery) to the serial line LANC via a carrier, other electronic devices may decode the carrier on the serial line LANC by using a power carrier decoder, which is used as a party for decoding the carrier signal, the decoder generally has a sensor module, a band pass filter module, a processing unit such as a MCU/DSP, etc., the serial line passes through the sensor module (e.g., an air-core coil sensor, etc.), so that the sensor module detects the carrier signal on the transmission line, and in order to more accurately capture real carrier data and shield noise, the band pass filter module further filters the carrier signal sensed by the sensor module to filter out noise that is not in a designated frequency range, and only the carrier falling in the designated frequency range (close to the frequency of the driving signal DRI) may represent an expected real carrier signal, the processing unit decodes its carrier data after receiving the actual carrier signal. In the same way, the driving signal DRI from the processor 100 configured by the voltage conversion circuit CV _ K +1 drives the switching element S2 in the carrier transmitting module SIG configured by CV _ K +1 to switch on and off, so that the branch of CV _ K +1 actively introduces a disturbing signal between the first output terminal N1_ K +1 and the second input terminal NX2 due to the off/on of the driving signal DRI driving the switching element S2, and the disturbing signal is directly injected onto the serial line LANC from the first output terminal N1_ K + 1. That is, data of all individual batteries on the entire string of battery strings can be sent in a carrier wave manner to the same string line.

Referring to fig. 2, it is found that the carrier signal transmitted by the carrier transmitting module SIG configured in the voltage converting circuit CV _ K +1 needs to pass between the first and second output terminals N1_ K and N2_ K of the voltage converting circuit CV _ K to be broadcast to the entire serial connection line LANC, otherwise the carrier signal transmitted by the carrier transmitting module SIG configured in the voltage converting circuit CV _ K +1 is intercepted at the voltage converting circuit CV _ K. Or, also, it can be said: the carrier signal transmitted by the carrier transmitting module SIG configured by the voltage converting circuit CV _ K is similar to the carrier signal transmitted by the carrier transmitting module SIG configured by the voltage converting circuit CV _ K, which needs to pass between the first and second output terminals N1_ K +1 and N2_ K +1 of the voltage converting circuit CV _ K +1 before being broadcast to the entire serial line LANC, otherwise, the carrier signal transmitted by the carrier transmitting module SIG configured by the voltage converting circuit CV _ K is intercepted at the voltage converting circuit CV _ K + 1. This doubt must be taken into account, so we divide the series multi-stage voltage conversion circuit: defining the first class and the second class requires consideration of how the carrier signal of the first class voltage conversion circuit propagates through the second class voltage conversion circuit, and consideration of how the carrier signal of the second class voltage conversion circuit propagates through the first class voltage conversion circuit.

Referring to fig. 2, the first and second types of multistage voltage conversion circuits are defined in the entire multistage voltage conversion circuits CV _1 to CV _ N, and for example, specifically, it is assumed in advance that the first type of voltage conversion circuit CV _ K +1 corresponds to the photovoltaic cell PV _ K +1, and that the second type of voltage conversion circuit CV _ K corresponds to the photovoltaic cell PV _ K. The carrier signal transmitted by the carrier transmission module SIG of the first type of voltage conversion circuit CV _ K +1 needs to be propagated through a path between the first output terminal N1_ K and the second output terminal N2_ K of the second type of voltage conversion circuit CV _ K. In an alternative embodiment, the path of carrier propagation is: from one of the first and second output terminals N1_ K and N2_ K of the second type voltage conversion circuit CV _ K, to the first capacitor C1 of the second type voltage conversion circuit CV _ K, and then to the other one of the first and second output terminals N1_ K and N2_ K via the first capacitor C1 itself. A specific embodiment is illustrated as follows: the carrier signal of the first type voltage conversion circuit CV _ K +1 is injected into the serial line LANC from the first output terminal N1_ K +1, the carrier signal is firstly transmitted from the second output terminal N2_ K of the second type voltage conversion circuit CV _ K to the first capacitor C1 of the second type voltage conversion circuit CV _ K, and then is transmitted to the first output terminal N1_ K through the first capacitor C1 itself, and certainly, the carrier signal is transmitted from the first capacitor C1 itself, is transmitted through the inductor L2, and then is transmitted to the first output terminal N1_ K, as shown in the path of the thick dashed line in fig. 2. In fig. 2, a second capacitor C2 is connected between the first input terminal NX1 and the second input terminal NX2 of the voltage conversion circuit CV _ K, so another propagation path is: the processor 100 of the second type voltage conversion circuit CV _ K first turns on the switch tube S1 and stops driving the second type voltage conversion circuit CV _ K to perform voltage conversion, that is, does not perform voltage conversion of MPPT, it is noted that the switch tube S1 is not continuously turned on but is alternately turned off and on when performing maximum power tracking, at this stage, the carrier signal sent by the first type voltage conversion circuit CV _ K +1 enters the second output terminal N2_ K of the second type voltage conversion circuit CV _ K, and then propagates to the second input node NX2 of the second type voltage conversion circuit CV _ K via the inductor L1, the carrier wave then propagates to the first input node NX1 of the second type of voltage converting circuit CV _ K via the second capacitance C2 in the second type of voltage converting circuit CV _ K, and the carrier wave continues to propagate from the first input node NX1 of the second type voltage conversion circuit CV _ K to the first output terminal N1_ K of the second type voltage conversion circuit CV _ K via said inductor L2; in the subsequent stage until the first type of voltage conversion circuit CV _ K +1 no longer transmits the carrier signal, the processor 100 of the second type of voltage conversion circuit CV _ K controls its switching tube S1 to be alternately turned on and off so as to drive the second type of voltage conversion circuit CV _ K to perform DC-DC voltage conversion recovery and perform MPPT. The advantages are that: the second type of voltage conversion circuit CV _ K more easily controls the time node at which the first type of voltage conversion circuit CV _ K +1 transmits the carrier, because the second type voltage conversion circuit CV _ K may also send a carrier wave at a certain stage, in order to avoid the overlapping disorder of the signals sent by the second type voltage conversion circuit CV _ K and the first type voltage conversion circuit CV _ K +1, the circulation of the carrier wave signal sent by the first type voltage conversion circuit CV _ K +1 is clamped by controlling the turn-off of the switch tube S1 in the second type voltage conversion circuit CV _ K, then the switching tube S1 in the second type voltage conversion circuit CV _ K is not switched on until the procedure of the second type voltage conversion circuit CV _ K itself sending the carrier signal is completely finished, thereby allowing the carrier signal from the first type voltage conversion circuit CV _ K +1 to flow smoothly to the series line LANC through the path in the second type voltage conversion circuit CV _ K. It is worth noting that: in the above, it is assumed that the photovoltaic cell PV _ K +1 corresponds to the first type of voltage conversion circuit CV _ K +1, and the photovoltaic cell PV _ K corresponds to the second type of voltage conversion circuit CV _ K. The actual voltage conversion circuit CV _ K and the voltage conversion circuit CV _ K +1 may be reversed in terms of designation, for example, the former is classified as a first type of voltage conversion circuit and the latter is classified as a second type.

Referring to fig. 2, the present invention also discloses a data communication method based on the energy optimization system, wherein a battery string is formed by connecting multiple photovoltaic cells PV _1 to PV _ N in series, and the multiple voltage conversion circuits CV _1 to CV _ N corresponding to the multiple photovoltaic cells PV _1 to PV _ N are connected in series in the following manner: the second output terminal N2_ K of any previous stage of the voltage converting circuit CV _ K is connected to the first output terminal N1_ K +1 of the voltage converting circuit CV _ K +1 of the next stage through the serial connection line LANC. Each stage of the voltage conversion circuit CV _ K is further provided with a processor 100 and a carrier transmission module SIG. The data communication method performed by the voltage conversion circuit CV _ K of any stage includes: one path of the driving signal DRI output by the processor 100 in the voltage converting circuit CV _ K of any stage is used to drive the switching element S2 of the carrier transmitting module SIG in CV _ K, and the switching element S2 is switched on and off, so that the carrier transmitting module SIG injects the generated carrier signal from the first output terminal N1_ K of the voltage converting circuit CV _ K of any stage onto the serial line LANC. Note that wherein: the driving signal DIR for driving the switching element S2 in the carrier transmission module SIG is set to be at the ground reference potential with the negative electrode of the photovoltaic cell PV _ K of the stage corresponding to the voltage conversion circuit CV _ K of the arbitrary stage. It is known to those skilled in the art that the high and low levels of the driving signal DRI are defined as a fraction of the high and low levels with respect to a certain reference potential, and the high and low levels of the driving signal DIR for the switching element S2 in CV _ K are referenced to the negative electrode of the photovoltaic cell PV _ K as the ground reference or to the virtual ground GND-1 as the reference voltage. The same reasoning applies to the high and low levels of the driving signal DRI for the switching element S2 in CV _ K +1, with the negative electrode of the photovoltaic cell PV _ K +1 as the reference ground or virtual ground GND-2 as the reference voltage. The potentials of GND-1 and GND-2 are different in practice, and the above driving design can better adapt to the potential difference.

Referring to fig. 2, in one embodiment: the carrier sending module SIG configured by each stage of voltage conversion circuit comprises a branch circuit which is connected in series between a first output end and a second input end and comprises a first resistor, a bypass capacitor and a switch element, and a second resistor which is connected in parallel at two ends of the bypass capacitor is further arranged in the branch circuit. The carrier transmitting module SIG, which takes the voltage converting circuit CV _ K as an example, comprises a first resistor R1 and a bypass capacitor C connected in series between a first output terminal N1_ K and a second input terminal NX2_BCAnd a branch of the switching element S2, wherein a second resistor R2 connected in parallel with two ends of the bypass capacitor is arranged in the branch. Wherein a first resistor R1 and a bypass capacitor C are arranged between a first terminal (e.g. drain terminal of NMOS) of the switching element S2 and a first output terminal N1_ K of the voltage conversion circuit CV _ K_BCAnd a second terminal (e.g., a source terminal of the NMOS) of the switching element S2 is connected to the negative terminal of the photovoltaic cell PV _ K corresponding to the voltage conversion circuit CV _ K.

Referring to fig. 2, in one embodiment: defining a first class and a second class of multi-stage voltage conversion circuits in the whole multi-stage voltage conversion circuits CV _1 to CV _ N, and assuming that the first class voltage conversion circuit CV _ K +1 corresponds to the photovoltaic cell PV _ K +1 and the second class voltage conversion circuit CV _ K corresponds to the photovoltaic cell PV _ K in advance; the carrier signal transmitted by the carrier transmission module SIG of the first type voltage conversion circuit CV _ K +1 needs to be transmitted through a path between the first output terminal N1_ K and the second output terminal N2_ K of the second type voltage conversion circuit CV _ K; and the path of the path is: from one of the first and second output terminals (N1 _ K, N2_ K) of the second type voltage conversion circuit CV _ K, the carrier wave propagates to the first capacitor C1 of the second type voltage conversion circuit CV _ K, and then propagates to the other of the first and second output terminals (N1 _ K, N2_ K) via the first capacitor C1.

Referring to fig. 2, in one embodiment: a second capacitor may be connected between the first input terminal and the second input terminal of the voltage conversion circuit, for example: a second capacitor C2 is connected between the first input terminal NX1 and the second input terminal NX2 of the voltage conversion circuit CV _ K; a second capacitor C2 is connected between the first input end NX1 and the second input end NX2 of the voltage conversion circuit CV _ K +1, and the second capacitor C2 can stabilize photovoltaic voltage fluctuation.

Referring to fig. 3, slightly different from fig. 2, the carrier transmitting module configured in each stage of the voltage converting circuit in fig. 2 includes a branch circuit including a first resistor, a bypass capacitor and a switch element, which is connected in series between a first output terminal and a second input terminal, and a second resistor connected in parallel to two ends of the bypass capacitor is further disposed in the branch circuit. Still take the voltage conversion circuit CV _ K as an example: the carrier transmitting module SIG configured by the voltage converting circuit CV _ K in fig. 2 includes a first resistor R1 and a bypass capacitor C connected in series between the first output terminal N1_ K and the second input terminal NX2_BCAnd a branch of the switching element S2, wherein a second resistor R2 connected in parallel with two ends of the bypass capacitor is arranged in the branch. The carrier transmitting module SIG provided with the voltage converting circuit CV _ K in fig. 3 includes a first resistor R1 and a bypass capacitor C connected in series between the second output terminal N2_ K and the second input terminal NX2_BCAnd a branch of the switch element S2, wherein a second resistor R2 connected in parallel with two ends of the bypass capacitor is also arranged in the branch. The data communication method performed by the voltage conversion circuit CV _ K in fig. 2 includes: one path of the driving signal DRI output by the processor 100 in the voltage conversion circuit CV _ K is used to drive the switching element S2 in the carrier transmitting module SIG, so that the carrier transmitting module injects the carrier signal from the first output terminal N1_ K of the voltage conversion circuit CV _ K onto the serial line LANC. The data communication method performed by the voltage conversion circuit CV _ K in fig. 3 includes: one path of the driving signal DRI output by the processor 100 in the voltage conversion circuit CV _ K is used to drive the switching element S2 in the carrier transmitting module, so that the carrier transmitting module injects the carrier signal from the second output terminal N2_ K of the voltage conversion circuit CV _ K onto the serial line LANC. There is a slight difference between the injection of the carrier signal from the first output terminal N1_ K to the serial line LANC and the injection of the carrier signal from the second output terminal N2_ K to the serial line LANC, for example, the latter is easier to make the carrier penetration voltage conversion circuit CV _ K itself wider than the formerAnd onto the serial line LANC, since the inductance L2 in the former scheme presents a higher impedance to the carrier than the latter. The embodiment of fig. 3 is substantially the same as the embodiment of fig. 2 except for the differences described above.

Referring to fig. 5, a slight improvement is made on the basis of fig. 3, taking the voltage conversion circuit CV _ K as an example, a compensation capacitor C is connected in series between the first output terminal N1_ K and the second output terminal N2_ K of the voltage conversion circuit CV _ K_P1And a control switch S3, the control switch S3 being driven by the processor 100 configured by the voltage conversion circuit CV _ K. The processor 100 further drives the control switch S3 to turn off in a stage of driving the carrier transmission module SIG to transmit the carrier signal to the tandem line LANC, and the processor 100 drives the control switch S3 to turn on only in a stage of not transmitting the carrier signal by the carrier transmission module SIG. Introducing a compensation capacitor C when the control switch S3 is switched on_P1The output ripple of the voltage conversion circuit can be filtered, and at this time, a carrier path is also formed between the first output terminal N1_ K and the second output terminal N2_ K, for example, assuming that the voltage conversion circuit CV _ K is a second type voltage conversion circuit, a carrier signal sent by the carrier sending module SIG of the first type voltage conversion circuit CV _ K +1 can be sent from the compensation capacitor C_P1Is propagated.

Referring to fig. 4, a slight improvement is made on the basis of fig. 3, taking the voltage conversion circuit CV _ K as an example, a compensation capacitor C is connected in series between the second output terminal N2_ K and the second input terminal NX2 of the voltage conversion circuit CV _ K_P1And a control switch S3, the control switch S3 being driven by the processor 100 configured by the voltage conversion circuit CV _ K. In the stage that the processor 100 drives the carrier transmission module SIG to transmit the carrier signal to the tandem line LANC, the processor 100 further drives the control switch S3 to be turned off, and only in the stage that the carrier transmission module SIG does not transmit the carrier signal, the processor 100 drives the control switch S3 to be turned on. Introducing a compensation capacitor C when the control switch S3 is switched on_P1The output ripple of the voltage conversion circuit can be filtered, and a carrier path is also formed between the second output terminal N2_ K and the second input terminal NX2 at this time, for example, assuming that the voltage conversion circuit CV _ K is a second type voltage conversion circuit, a carrier transmitted by the carrier transmission module SIG of the first type voltage conversion circuit CV _ K +1The signal can be compensated by a compensation capacitor C_P1And then to the second capacitor C2.

Referring to fig. 6, a slight improvement is made on the basis of fig. 2, taking the voltage conversion circuit CV _ K as an example, a compensation capacitor C is connected in series between the first output terminal N1_ K and the second input terminal NX2 of the voltage conversion circuit CV _ K_P2And a control switch S4, the control switch S4 being driven by the processor 100 configured by the voltage conversion circuit CV _ K. The processor 100 further drives the control switch S4 to turn off during a stage when the carrier transmission module SIG is driven to transmit the carrier signal to the serial lan nc, and drives the control switch S4 to turn on only during a stage when the carrier transmission module SIG does not transmit the carrier signal. Introducing a compensation capacitor C when the control switch S4 is switched on_P2The output ripple of the voltage converting circuit itself can be filtered, and at this time, a carrier path is also formed between the first output terminal N1_ K and the interconnection node NX3, for example, assuming that the voltage converting circuit CV _ K is a second type of voltage converting circuit, it can be known that the carrier signal transmitted by the carrier transmitting module SIG of the first type of voltage converting circuit CV _ K-1 of the adjacent previous stage can propagate through the compensation capacitor C in addition to the above-mentioned propagation path from N1_ K to N2_ K_P2The path to node NX3 and to N2_ K.

Referring to fig. 7, a slight improvement is made on the basis of fig. 2, taking the voltage conversion circuit CV _ K as an example, a compensation capacitor C is connected in series between the first output terminal N1_ K and the second output terminal N2_ K of the voltage conversion circuit CV _ K_P2And a control switch S4, the processor 100 further drives the control switch S4 to turn off during a stage when the processor 100 drives the carrier transmission module SIG to transmit the carrier signal to the serial line LANC, and the processor 100 drives the control switch S4 to turn on only during a stage when the carrier transmission module SIG does not transmit the carrier signal. The advantage of fig. 5 can also be seen in fig. 7.

The invention discloses a data communication method based on the system, which comprises the following steps that firstly, multi-stage photovoltaic cells PV _1 to PV _ N are connected in series to form a battery pack string, and multi-stage voltage conversion circuits CV _1 to CV _ N corresponding to the multi-stage photovoltaic cells PV _1 to PV _ N are connected in series in the following mode: the second output end of any previous stage voltage conversion circuit is connected to the first output end of the voltage conversion circuit of the adjacent next stage through the serial connection lines; each level of voltage conversion circuit is also provided with a processor and a carrier sending module; the data communication method performed by the voltage conversion circuit of any stage includes: a path of driving signal output by the processor in the voltage converting circuit of any stage is used to drive a switching element in the carrier sending module, so that the carrier sending module injects a carrier signal from the first output end of the voltage converting circuit of any stage onto the serial connection line, see the embodiment shown in fig. 2; the driving signal for driving the switching element in the carrier sending module takes the cathode of the first-stage photovoltaic cell corresponding to the voltage conversion circuit of any stage as a reference ground potential. Fig. 2 illustrates an example of a data communication method performed by the voltage conversion circuit CV _ K: one path of the driving signal DRI output by the processor 100 in the voltage conversion circuit CV _ K is used to drive the switching element S2 in the carrier transmitting module SIG, so that the carrier transmitting module SIG injects the carrier signal from the first output terminal N1_ K of the voltage conversion circuit CV _ K to the serial line LANC. The driving signal DRI driving the switching element S2 in the carrier transmission module SIG is set to the negative electrode of the photovoltaic cell PV _ K of the stage corresponding to the voltage conversion circuit CV _ K as the reference ground potential. In another embodiment, the invention further discloses a data communication method based on the system, wherein a battery string is formed by connecting multiple photovoltaic cells in series, and the mode of connecting the multiple voltage conversion circuits corresponding to the multiple photovoltaic cells in series is as follows: the second output end of any previous-stage voltage conversion circuit is connected to the first output end of the adjacent next-stage voltage conversion circuit through a serial connection wire; each level of voltage conversion circuit is also provided with a processor and a carrier sending module; the data communication method performed by the voltage conversion circuit of any stage includes: a path of driving signal output by the processor in the voltage converting circuit of any stage is used to drive the switching element in the carrier sending module, so that the carrier sending module injects the carrier signal from the second output end of the voltage converting circuit of any stage onto the serial connection line, see the embodiment of fig. 3; the driving signal for driving the switching element in the carrier transmitting module takes the negative electrode of the first-stage photovoltaic cell corresponding to the voltage conversion circuit of any stage as a reference ground potential. In fig. 3, a data communication method performed by the voltage conversion circuit CV _ K is taken as an example: one path of the driving signal DRI output by the processor 100 in the voltage conversion circuit CV _ K is used to drive the switching element S2 in the carrier transmitting module SIG, so that the carrier transmitting module SIG injects the carrier signal from the second output terminal N2_ K of the voltage conversion circuit CV _ K to the serial line LANC, and the driving signal DRI driving the switching element S2 in the carrier transmitting module SIG is based on the negative electrode of the photovoltaic cell PV _ K of the stage corresponding to the voltage conversion circuit CV _ K of any stage as the reference ground potential.

While the present invention has been described with reference to the preferred embodiments and illustrative embodiments, it is to be understood that the invention as described is not limited to the disclosed embodiments. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. Therefore, the appended claims should be construed to cover all such variations and modifications as fall within the true spirit and scope of the invention. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of the present invention.

Claims

1. An energy optimization system for power optimization of photovoltaic cells, comprising:

the photovoltaic cell is provided with a voltage conversion circuit which executes maximum power tracking, a first input end and a second input end of the voltage conversion circuit are connected to a positive electrode and a negative electrode of the corresponding photovoltaic cell, and the voltage provided by the photovoltaic cell after power optimization is carried out is output at a first output end and a second output end of the voltage conversion circuit;

wherein:

the voltage conversion circuit is connected with a switching tube and a first inductor in series between a second input end and a second output end, the first input end and the first output end are connected with the second inductor, a diode is connected between the interconnection node between the switching tube and the first inductor and the first input end, and a first capacitor is connected between the second output end and the first input end;

the method comprises the following steps that multiple photovoltaic cells are connected in series to form a battery string, the voltage output by the voltage conversion circuit corresponding to each photovoltaic cell represents the actual voltage provided by the photovoltaic cell on the battery string, wherein the multiple voltage conversion circuits corresponding to the multiple photovoltaic cells are connected in series in the following mode: the second output end of any previous-stage voltage conversion circuit is connected to the first output end of the adjacent next-stage voltage conversion circuit through a serial connection wire;

the voltage conversion circuit configured by any one stage of photovoltaic cell is also provided with a processor and a carrier sending module, wherein the working parameters of any one stage of photovoltaic cell are sent to the tandem connection line by the processor of the voltage conversion circuit corresponding to the working parameters through driving the carrier sending module;

defining a first class and a second class of multi-stage voltage conversion circuits in the whole multi-stage voltage conversion circuit, wherein a carrier signal sent by a carrier sending module of the first class of voltage conversion circuit needs to be propagated by a path between a first output end and a second output end of the second class of voltage conversion circuit, and the path is as follows: propagating from one of the first and second output terminals of the second class of voltage converting circuit to the first capacitance of the second class of voltage converting circuit to the other of the first and second output terminals.

2. The energy optimization system according to claim 1, wherein the carrier transmitter module of each stage of the voltage converting circuit comprises a branch circuit including a first resistor, a bypass capacitor and a switching element, connected in series between the first output terminal and the second input terminal, and a second resistor connected in parallel across the bypass capacitor is further disposed in the branch circuit.

3. The energy optimization system of claim 1, wherein a second capacitor is coupled between the first input terminal and the second input terminal of the voltage conversion circuit.

4. The energy optimization system according to claim 2, wherein a compensation capacitor and a control switch are connected in series between the first output terminal and the second input terminal, the processor further drives the control switch to be turned off during a period in which the carrier transmission module is driven to transmit the carrier signal to the serial line, and drives the control switch to be turned on only during a period in which the carrier transmission module is not transmitting the carrier signal.

5. The energy optimization system according to claim 2, wherein a compensation capacitor and a control switch are connected in series between the first output terminal and the second output terminal, the processor drives the control switch to be turned off during a period in which the carrier transmission module is driven to transmit the carrier signal to the serial line, and drives the control switch to be turned on only during a period in which the carrier transmission module is not transmitting the carrier signal.

6. The energy optimization system according to claim 1, wherein the carrier transmitter module of each stage of the voltage converting circuit comprises a branch circuit including a first resistor, a bypass capacitor and a switching element, connected in series between the second output terminal and the second input terminal, and a second resistor connected in parallel across the bypass capacitor is further disposed in the branch circuit.

7. The energy optimization system according to claim 6, wherein a compensation capacitor and a control switch are connected in series between the second output terminal and the second input terminal, the processor further drives the control switch to be turned off during a period in which the carrier transmission module is driven to transmit the carrier signal to the serial line, and drives the control switch to be turned on only during a period in which the carrier transmission module is not transmitting the carrier signal.

8. The energy optimization system according to claim 6, wherein a compensation capacitor and a control switch are connected in series between the first output terminal and the second output terminal, the processor further drives the control switch to be turned off during a period in which the carrier transmission module is driven to transmit the carrier signal to the serial line, and drives the control switch to be turned on only during a period in which the carrier transmission module is not transmitting the carrier signal.

9. A data communication method based on an energy optimization system, wherein the energy optimization system for power optimization of photovoltaic cells comprises: the photovoltaic cell is provided with a voltage conversion circuit which executes maximum power tracking, a first input end and a second input end of the voltage conversion circuit are connected to a positive electrode and a negative electrode of the corresponding photovoltaic cell, and the voltage provided by the photovoltaic cell after power optimization is carried out is output at a first output end and a second output end of the voltage conversion circuit, wherein: the voltage conversion circuit is connected with a switching tube and a first inductor in series between a second input end and a second output end, the first input end and the first output end are connected with the second inductor, a diode is connected between the interconnection node between the switching tube and the first inductor and the first input end, and a first capacitor is connected between the second output end and the first input end;

a battery pack string is formed by connecting multiple photovoltaic cells in series, and the mode of connecting multiple voltage conversion circuits corresponding to the multiple photovoltaic cells in series is as follows: the second output end of any previous-stage voltage conversion circuit is connected to the first output end of the adjacent next-stage voltage conversion circuit through a serial connection wire; each level of voltage conversion circuit is also provided with a processor and a carrier sending module;

the data communication method performed by the voltage conversion circuit of any stage includes:

one path of driving signal output by the processor in the voltage conversion circuit of any stage is used for driving a switch element in the carrier sending module, so that the carrier sending module injects the carrier signal from the first output end of the voltage conversion circuit of any stage to the serial line;

10. The method of claim 9, wherein the carrier transmitter module of each stage of the voltage converting circuit comprises a branch circuit including a first resistor, a bypass capacitor and a switching element connected in series between a first output terminal and a second input terminal, and a second resistor connected in parallel across the bypass capacitor is disposed in the branch circuit;

wherein:

a first resistor and a bypass capacitor are arranged between the first end of the switching element and the first output end of the voltage conversion circuit, and the second end of the switching element is connected to the negative electrode of the primary photovoltaic cell corresponding to the voltage conversion circuit.

11. The method of claim 9, wherein the first and second classes of multi-level voltage converting circuits are defined throughout the multi-level voltage converting circuit; wherein

The carrier signal sent by the carrier sending module of the first class voltage conversion circuit needs to be propagated by a path between the first output end and the second output end of the second class voltage conversion circuit, and the path is as follows: propagating from one of the first and second output terminals of the second class of voltage converting circuit to the first capacitance of the second class of voltage converting circuit to the other of the first and second output terminals.

12. The method of claim 9, wherein a compensation capacitor and a control switch are connected in series between the first output terminal and the second input terminal, the processor drives the control switch to be turned off during a period when the processor drives the carrier transmission module to transmit the carrier signal to the serial line, and drives the control switch to be turned on only during a period when the carrier transmission module does not transmit the carrier signal.

13. The method of claim 9, wherein a compensation capacitor and a control switch are connected in series between the first output terminal and the second output terminal, the processor drives the control switch to be turned off during a stage of driving the carrier transmission module to transmit the carrier signal to the serial line, and the processor drives the control switch to be turned on only during a stage of not transmitting the carrier signal by the carrier transmission module.

14. A data communication method based on an energy optimization system, wherein the energy optimization system for power optimization of photovoltaic cells comprises: the photovoltaic cell is provided with a voltage conversion circuit which executes maximum power tracking, a first input end and a second input end of the voltage conversion circuit are connected to a positive electrode and a negative electrode of the corresponding photovoltaic cell, and the voltage provided by the photovoltaic cell after power optimization is carried out is output at a first output end and a second output end of the voltage conversion circuit, wherein: the voltage conversion circuit is connected with a switching tube and a first inductor in series between a second input end and a second output end, the first input end and the first output end are connected with the second inductor, a diode is connected between the interconnection node between the switching tube and the first inductor and the first input end, and a first capacitor is connected between the second output end and the first input end;

one path of driving signal output by the processor in the voltage conversion circuit of any stage is used for driving a switch element in the carrier sending module, so that the carrier sending module injects the carrier signal from the second output end of the voltage conversion circuit of any stage to the serial line;

15. The method of claim 14, wherein the carrier transmitter module of each stage of the voltage converting circuit comprises a branch circuit including a first resistor, a bypass capacitor and a switching element connected in series between a second output terminal and a second input terminal, and a second resistor connected in parallel across the bypass capacitor is disposed in the branch circuit;

wherein:

a first resistor and a bypass capacitor are arranged between the first end of the switching element and the second output end of the voltage conversion circuit, and the second end of the switching element is connected to the negative electrode of the primary photovoltaic cell corresponding to the voltage conversion circuit.

16. The method of claim 14, wherein the first and second classes of multi-level voltage converting circuits are defined throughout the multi-level voltage converting circuit; wherein

17. The method of claim 14, wherein a compensation capacitor and a control switch are connected in series between the second output terminal and the second input terminal, the processor drives the control switch to be turned off during a period when the processor drives the carrier transmission module to transmit the carrier signal to the serial line, and drives the control switch to be turned on only during a period when the carrier transmission module does not transmit the carrier signal.

18. The method of claim 14, wherein a compensation capacitor and a control switch are connected in series between the first output terminal and the second output terminal, the processor drives the control switch to be turned off during a period when the processor drives the carrier transmission module to transmit the carrier signal to the serial line, and drives the control switch to be turned on only during a period when the carrier transmission module does not transmit the carrier signal.