Phase synchronization communication circuit for inverter parallel operation detection and inverter parallel operation structure

Abstract

The utility model relates to the technical field of photovoltaic power supply, and discloses a phase synchronization communication circuit for inverter parallel operation detection and an inverter parallel operation structure, comprising a main transmitting branch and a main receiving branch which are arranged at an inverter host end, and slave transmitting branches and slave receiving branches which are arranged at each inverter slave end, the main transmitting branch is respectively connected with the receiving branch of each inverter slave end through a corresponding communication cable, the main receiving branch is respectively connected with the transmitting branch of each inverter slave end through a corresponding communication cable, and the main transmitting branch and the slave transmitting branch have the same structure. And the main receiving branch and the slave receiving branch have the same structure and are both constructed by phase inverters and photoelectric couplers.

Description

Technical Field

[0001] This utility model belongs to the technical field of photovoltaic power supply, specifically relating to a phase synchronization communication circuit and inverter parallel operation structure for inverter parallel operation detection. Background Technology

[0002] With the rapid advancement of photovoltaic energy storage technology, especially the rapid development of energy storage and off-grid inverter technology, the power supply reliability and modular design requirements of energy storage inverters are becoming increasingly demanding, and the system power requirements are becoming increasingly larger. More and more products are beginning to add parallel or grid-connected functions to meet the needs of high power and redundancy in modular design, while also placing higher demands on the reliability of parallel signal circuits.

[0003] Currently, communication methods such as RS485 or CAN networks are mostly used to transmit parallel synchronization signals such as L1 phase synchronization signals. When transmitting signals, encoding and decoding according to existing communication protocols are required, which takes a long time. The communication rate is generally tens of milliseconds, which is difficult to meet the needs of parallel communication. At the same time, if bit errors or interference occur, it can easily lead to problems in parallel operation or even cause the entire system to fail.

[0004] Therefore, there is an urgent need for a practical solution to address the parallel communication problem in order to meet the needs of real-world applications. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides a phase synchronization communication circuit and inverter parallel operation structure for inverter parallel operation detection, which solves the technical problems of low speed and easy bit error faults in existing technologies that rely on RS485 or CAN networks to achieve inverter parallel operation communication.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A phase synchronization communication circuit for inverter parallel operation detection includes a main transmitter branch and a main receiver branch located at the inverter master end, and slave transmitter branches and slave receiver branches located at the slave ends of each inverter.

[0008] The main transmitting branch is connected to the receiving branch of each inverter slave unit via a corresponding communication cable, and the main receiving branch is connected to the transmitting branch of each inverter slave unit via a corresponding communication cable.

[0009] The main transmitting branch and the slave transmitting branch have the same structure, and the main receiving branch and the slave receiving branch have the same structure; they are both constructed from inverters and optocouplers.

[0010] Furthermore, the main transmitting branch is connected to each of the slave receiving branches via their respective communication cables, and the main receiving branch is also connected to each of the slave transmitting branches via their respective communication cables.

[0011] Furthermore, both the main transmitting branch and the slave transmitting branch include a first inverter, a second inverter, a first optocoupler, and a third inverter connected in sequence;

[0012] Both the main receiving branch and the slave receiving branch include a fourth inverter, a second optocoupler, a fifth inverter, and a sixth inverter connected in sequence.

[0013] Furthermore, the third inverter of the main transmitting branch is connected to the fourth inverter of each of the slave receiving branches via a communication cable.

[0014] The fourth inverter of the main receiving branch and the third inverter of each of the slave transmitting branches are also connected through their respective communication cables.

[0015] Furthermore, diodes are connected to the output terminals of the third inverters in both the main transmitting branch and the slave transmitting branch.

[0016] Furthermore, both the main transmitting branch and the main receiving branch are connected to the processor at the inverter master unit, and both the slave transmitting branch and the slave receiving branch are connected to the processor at the corresponding inverter slave unit.

[0017] An inverter parallel operation structure includes multiple inverters, one of which serves as the master inverter and the others as slave inverters. The master inverter and each slave inverter are connected via the phase synchronization communication circuit described above for inverter parallel operation detection.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] (1) Compared with conventional communication methods such as RS485 or CAN network, the detection results of the L1 phase of each inverter participating in the inverter parallel operation can be quickly transmitted with the help of the phase synchronization communication circuit of this utility model, which meets the communication rate requirements of inverter parallel operation, ensures the smooth operation of inverter parallel operation, and reduces the failure rate of the entire power grid system. It is highly practical and easy to promote and apply.

[0020] (2) By cleverly using multiple inverters and optocouplers to construct a dedicated communication circuit, the circuit structure is simple and reliable, highly operable, and the optocoupler can be used to transmit and isolate electrical signals with the help of optical signals. There is no direct electrical contact, which effectively blocks the interference transmission between high voltage and low voltage circuits, and between strong and weak currents, eliminates noise interference, and ensures signal integrity. At the same time, the insulating material of the optocoupler can withstand thousands of kilovolts, which can prevent high voltage from entering the low voltage circuit and ensure the safety of personnel and equipment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the connection structure of the phase synchronization communication circuit of this utility model applied to inverter parallel operation;

[0022] Figure 2 This is a schematic diagram of the dedicated communication circuit of this utility model. Figure 1 ;

[0023] Figure 3 This is a schematic diagram of the dedicated communication circuit of this utility model. Figure 2 . Detailed Implementation

[0024] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the inverter circuit structure of this utility model. It should be noted that the description of these embodiments is for the purpose of helping to understand this utility model, but does not constitute a limitation on this utility model.

[0025] like Figure 1 As shown, this utility model provides a phase synchronization communication circuit for inverter parallel operation detection, including a main transmitter branch and a main receiver branch disposed at the inverter master end, and slave transmitter branches and slave receiver branches disposed at the slave ends of each inverter. The main transmitter branch is connected to the receiver branch at the slave end of each inverter through corresponding communication cables, and the main receiver branch is connected to the transmitter branch at the slave end of each inverter through corresponding communication cables.

[0026] The main transmitting branch and the slave transmitting branch have the same structure, and the main receiving branch and the slave receiving branch have the same structure; they are all constructed from inverters and optocouplers.

[0027] In this way, compared with conventional communication methods such as RS485 or CAN network, the detection results of the L1 phase of each inverter participating in inverter parallel operation can be quickly transmitted with the help of the phase synchronization communication circuit of this utility model, which meets the communication rate requirements of inverter parallel operation, ensures the smooth operation of inverter parallel operation, reduces the failure rate of the entire power grid system, is highly practical, and is easy to promote and apply.

[0028] Specifically as follows:

[0029] Assuming there are n inverters operating in parallel, each inverter mainly includes a boost module (DC / DC) and an inverter module (DC / AC). By boosting the voltage and then inverting the voltage, the energy of the photovoltaic modules (PV) is transmitted to the grid. They are constructed using a master-slave control method, where one inverter can be designated as the master and the remaining n-1 inverters as slaves. The phase of the master inverter is used as the reference, and the other slaves must track the synchronous phase signal of the master inverter.

[0030] To reduce the time consumption of the synchronization phase signal during transmission, this invention designs a dedicated communication circuit, such as... Figure 2 As shown, it includes a transmitting branch and a receiving branch. The transmitting branch includes a first inverter U1, a second inverter U2, a first optocoupler Q1, and a third inverter U3 connected in sequence. The receiving branch includes a fourth inverter U4, a second optocoupler Q2, a fifth inverter U5, and a sixth inverter U6 connected in sequence. The first inverter and the fourth inverter are connected by a communication cable.

[0031] Thus, when the signal transmitting end SYN_TX is low, it is processed by the first inverter U1 and the second inverter U2 to become low, then isolated by the first optocoupler Q1, and finally processed by the third inverter to become high. That is, the SYN_PHASE bus end is high and directly enters the communication cable for transmission.

[0032] The high level transmitted via the communication cable is then processed by the fourth inverter to become a low level, then isolated by the second optocoupler Q2, and finally processed by the fifth inverter U5 and the sixth inverter U6 to become a low level, so that the signal receiving end SYN_RX is also at a low level, thereby realizing the transmission of the phase synchronization signal.

[0033] When the signal transmitting end SYN_TX is high, the signal transmission process is similar to that described above. The SYN_PHASE bus end is low, and the signal receiving end SYN_RX is also high.

[0034] Since both the transmitting and receiving branches of this utility model are equipped with optocouplers, they can achieve the transmission and isolation of electrical signals with the help of optical signals. There is no direct electrical contact, which effectively blocks the interference transmission between high-voltage and low-voltage circuits, and between strong and weak currents, eliminates noise interference, and ensures signal integrity. In addition, the insulating material of the optocoupler can withstand thousands of volts, which can prevent high voltage from entering the low-voltage circuit and ensure the safety of personnel and equipment.

[0035] Simultaneously, two inverters are connected in series at the start of transmission in the transmitting branch and the end of reception in the receiving branch. Besides active signal processing, this increases load capacity and interference immunity. Furthermore, the two inverters connected in series can be replaced by operational amplifiers S1 / S2. The specific circuit connection is as follows: Figure 3 As shown, simply short-circuit the inverting input of the operational amplifier to the output, and then connect it between the optocoupler and the inverter.

[0036] In addition, this invention also connects a diode to the output of the third inverter in the transmitting branch to ensure the unidirectionality of signal transmission, that is, the signal is always transmitted from the transmitting branch to the receiving branch, thus avoiding the problem of signal backflow.

[0037] When the above-mentioned dedicated communication circuit is applied to inverters in parallel operation, we can set up a main transmitter branch and a main receiver branch at the inverter master end, and set up corresponding slave transmitter branches and slave receiver branches at the slave end of each inverter. These main transmitter branches and slave transmitter branches have the same structure, and the main receiver branches and slave receiver branches have the same structure. They are all the same as the transmitter branches and receiver branches mentioned above.

[0038] The main transmitting branch is connected to the receiving branch of each inverter slave via corresponding communication cables, and the main receiving branch is connected to the transmitting branch of each inverter slave via corresponding communication cables. They can all be connected via their own communication cables. That is, the third inverter of the main transmitting branch is connected to the fourth inverter of each slave receiving branch via a communication cable, and the fourth inverter of the main receiving branch is connected to the third inverter of each slave transmitting branch via their own communication cables. Then, the first inverter of the main transmitting branch and the sixth inverter of the main receiving branch are connected to the processor of the inverter master, and the first inverter of the slave transmitting branch and the sixth inverter of the slave receiving branch are connected to the processor of the corresponding inverter slave.

[0039] In this way, the phase synchronization communication circuit of this utility model can quickly send the phase signal from the inverter master to each inverter slave, and the phase signal from each inverter slave can also be quickly fed back to the inverter master. The transmission rate of phase information is <2ms, which can fully meet the high-speed communication requirements of inverter parallel operation.

[0040] In addition, this utility model also provides an inverter parallel operation structure, including multiple inverters, one of which serves as the master unit and the other inverters serve as slave units. The master unit and each slave unit are connected through the phase synchronization communication circuit for inverter parallel operation detection described above, so as to realize high-speed communication between the master unit and the slave units.

[0041] It is important to note that the schemes and arrangements of this application shown in the exemplary embodiments are merely exemplary. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible without substantially departing from the novel teachings and advantages of the subject matter described in this application (e.g., variations in various parameter values ​​(temperature, power, humidity, etc.), installation arrangements, names, colors, logical orders, etc.). Therefore, all such modifications are also included within the scope of this invention, and the order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "apparatus plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of this invention. Therefore, this invention is not limited to the particular embodiments but extends to various modifications that still fall within the scope of the appended claims.

[0042] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the best mode of carrying out the present invention as currently considered, or those features that are not relevant to implementing the present invention) may be omitted.

[0043] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A phase synchronization communication circuit for inverter paralleling detection, characterized in that: The main transmitting branch and the main receiving branch are arranged at the host end of the inverter, and the slave transmitting branch and the slave receiving branch are arranged at the slave end of each inverter, The main transmitting branch is connected with the receiving branch of each inverter slave end through a corresponding communication cable, and the main receiving branch is connected with the transmitting branch of each inverter slave end through a corresponding communication cable, The main transmitting branch and the slave transmitting branch have the same structure, and the main receiving branch and the slave receiving branch have the same structure, which are all constructed by inverters and photoelectric couplers.

2. The phase synchronization communication circuit for parallel operation detection of inverters according to claim 1, characterized in that: The main transmitting branch and each slave receiving branch are connected through a corresponding communication cable, and the main receiving branch and each slave transmitting branch are also connected through a corresponding communication cable.

3. The phase synchronization communication circuit for parallel operation detection of inverters according to claim 2, wherein: The main transmitting branch and the slave transmitting branch both include a first inverter, a second inverter, a first photoelectric coupler and a third inverter connected in sequence; The main receiving branch and the slave receiving branch both include a fourth inverter, a second photoelectric coupler, a fifth inverter and a sixth inverter connected in sequence.

4. The phase synchronization communication circuit for parallel operation detection of inverters according to claim 3, wherein: The third inverter of the main transmitting branch is connected with the fourth inverter of each slave receiving branch through a communication cable; The fourth inverter of the main receiving branch is also connected with the third inverter of each slave transmitting branch through a corresponding communication cable.

5. The phase synchronization communication circuit for parallel operation detection of inverters according to claim 3, wherein: The output end of the third inverter of the main transmitting branch and the slave transmitting branch is connected with a diode.

6. The phase synchronization communication circuit for parallel operation detection of inverters according to claim 1, wherein: The main transmitting branch and the main receiving branch are connected with the processor of the inverter host end, and the slave transmitting branch and the slave receiving branch are connected with the processor of the corresponding inverter slave end.

7. A parallel inverter structure, characterized by: The application relates to a phase synchronization communication circuit for inverter parallel detection, and comprises a plurality of inverters, wherein one inverter is used as a host end, and the rest of the inverters are used as slave ends, the host end is connected with each slave end through the phase synchronization communication circuit for inverter parallel detection.

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