Photovoltaic system

Abstract

The utility model is applicable to the field of photovoltaic technology, and provides a photovoltaic system, the photovoltaic system comprises an inverter and at least one combiner box, the inverter comprises a DC bus, a power line carrier communication host circuit and a host magnetic ring, and the combiner box comprises a power line carrier communication slave circuit and a slave magnetic ring; a positive output cable of the combiner box is connected with the positive direct current bus, and a negative output cable of the combiner box is connected with the negative direct current bus; the host magnetic ring is sleeved on the direct current bus to couple a carrier signal, and the power line carrier communication host circuit is connected with the host magnetic ring; the slave magnetic ring is sleeved on an output cable of the combiner box, and the power line carrier communication slave circuit is connected with the slave magnetic ring. According to the technical scheme of the utility model, RS485 communication cables do not need to be laid, the construction cost of communication between the inverter and the combiner box can be reduced, and the communication stability is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaic, and particularly relates to a photovoltaic system. Background Art

[0002] In the prior art, there are mainly the following two ways for communication between an inverter and a busbar box:

[0003] 1. Use the 485 communication method for communication. However, this method requires laying 485 communication lines, which is difficult in wiring, has a high maintenance cost, and the 485 communication method also has problems of short communication distance and low communication efficiency.

[0004] 2. Use the wireless communication method for communication. However, this method has problems of unstable signal transmission and small signal coverage. Summary of the Utility Model

[0005] The photovoltaic system provided by the utility model aims to solve the problem of high communication cost between the inverter and the busbar box.

[0006] The utility model is implemented as follows. A photovoltaic system includes an inverter and at least one busbar box. The inverter includes a DC bus, a power line carrier communication host circuit, and a host magnetic ring. The busbar box includes a power line carrier communication slave circuit and a slave magnetic ring;

[0007] The positive output cable of the busbar box is connected to the positive DC bus, and the negative output cable of the busbar box is connected to the negative DC bus;

[0008] The host magnetic ring is sleeved on the DC bus to couple carrier signals, and the power line carrier communication host circuit is connected to the host magnetic ring;

[0009] The slave magnetic ring is sleeved on the output cable of the busbar box, and the power line carrier communication slave circuit is connected to the slave magnetic ring.

[0010] Furthermore, the power line carrier communication host circuit includes a carrier chip, a signal amplification circuit, and an isolation transformer;

[0011] The output end of the carrier chip is connected to the input end of the signal amplification circuit. The output end of the signal amplification circuit is connected to the primary winding of the isolation transformer. The secondary winding of the isolation transformer is connected to the coupling wire of the host magnetic ring.

[0012] Furthermore, the power line carrier communication host circuit further includes a filtering circuit. The input end of the filtering circuit is connected to the primary winding of the isolation transformer, and the output end of the filtering circuit is connected to the input end of the carrier chip.

[0013] Further, the carrier chip is a power line carrier communication chip.

[0014] Further, the host magnetic ring is sleeved on the positive DC bus.

[0015] Further, the host magnetic ring is sleeved on the negative DC bus.

[0016] Further, the slave magnetic ring is sleeved on the positive output cable of the busbar box.

[0017] Further, the slave magnetic ring is sleeved on the negative output cable of the busbar box.

[0018] Further, the photovoltaic system further includes a filter capacitor;

[0019] The filter capacitor is connected between the positive DC bus and the negative DC bus.

[0020] In the technical solution of the present utility model, the power line carrier communication host circuit in the inverter can transmit the carrier signal to the busbar box through the coupling of the host magnetic ring, and the power line carrier communication slave circuit of the busbar box can couple the carrier signal through the slave magnetic ring to realize the communication between the inverter and the busbar box. Since there is no need to specially lay RS485 communication lines for the interaction signals between the inverter and the busbar box, the construction cost is low and the later maintenance is simple. Therefore, the communication cost between the inverter and the busbar box can be greatly reduced, and the communication distance and stability between the inverter and the busbar box can be increased by increasing the intensity of the carrier signal. With such a setting, compared with the wireless communication method, the signal transmission is more stable and the reliability is higher. Description of the Drawings

[0021] Figure 1 is the network structure block diagram of the photovoltaic system in an embodiment;

[0022] Figure 2 is the circuit structure block diagram of an embodiment of the photovoltaic system of the present utility model;

[0023] Figure 3 is the circuit structure block diagram of an embodiment of the power line carrier communication host circuit of the present utility model. Detailed Embodiment

[0024] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0025] In the technical solution of the present utility model, the power line carrier communication host circuit in the inverter can transmit the carrier signal to the busbar box through the host magnetic ring coupling, and the power line carrier communication slave circuit in the busbar box can couple the carrier signal through the slave magnetic ring to realize the communication between the inverter and the busbar box. With such a setting, the signal interaction between the inverter and the busbar box does not require a dedicated RS485 communication line to be laid, which is convenient for later maintenance, greatly reduces the communication cost between the inverter and the busbar box, and compared with the wireless communication method, the signal transmission is more stable and the reliability is higher.

[0026] Referring to Figure 1 , in practical applications, the networking structure of the photovoltaic system often includes a single inverter, at least one busbar box and at least one photovoltaic array panel. Among them, one end of the busbar box is connected to the corresponding photovoltaic array panel, and the other end is connected to the inverter. If the 485 communication method is used to realize the communication between the inverter and the busbar box, there will be problems such as difficult wiring and high maintenance costs, and the 485 communication method also has problems such as short communication distance and low communication efficiency. In order to reduce the communication cost between the busbar box and the inverter, the inverter provided in this embodiment includes a power line carrier communication host circuit and a host magnetic ring, and the busbar box provided in this embodiment includes a power line carrier communication slave circuit and a slave magnetic ring. The inverter and the busbar box use power line carrier communication, that is, use a DC cable for carrier communication, without the need to specially lay a 485 communication line, so as to achieve the purpose of reducing the communication cost between the inverter and the busbar box.

[0027] Example 1

[0028] Referring to Figure 2 , the present utility model provides a photovoltaic system, which includes an inverter and at least one busbar box. Among them, the inverter includes a DC bus, a power line carrier communication host circuit 101 and a host magnetic ring 102, and the busbar box includes power line carrier communication slave circuits 201 to 20n and slave magnetic rings 301 to 30n. The specific connection method is as follows: the positive DC bus is connected to the positive output cable of the busbar box, and the negative DC bus is connected to the negative output cable of the busbar box; the host magnetic ring 102 is sleeved on the DC bus to couple the carrier signal, and the power line carrier communication host circuit 101 is connected to the host magnetic ring 102; the slave magnetic rings 301 to 30n in the busbar box are sleeved on the output cables of the busbar box, and the power line carrier communication slave circuits 201 to 20n are connected to the corresponding slave magnetic rings 301 to 30n.

[0029] In this embodiment, the power line carrier communication host circuit 101 includes circuit modules such as a carrier chip, a PA (power amplifier), and an isolation transformer. Among them, the power line carrier communication host circuit 101 and the power line carrier communication slave circuit use the power cable in the photovoltaic power station as the physical medium and utilize modulation and demodulation technologies to complete communication between devices. Its advantage is that there is no need to lay communication cables separately.

[0030] In this embodiment, the host magnetic ring 102 can be sleeved on the positive DC bus or the negative DC bus to couple the carrier signal. In other embodiments, magnetic devices of other shapes can also be used to couple the carrier signal with the DC bus, which can be specifically set according to actual needs. The slave magnetic ring can be sleeved on the positive output cable of the combiner box or the negative output cable of the combiner box, and there is no limit here.

[0031] It can be understood that since the host magnetic ring 102 is sleeved on the DC bus and the current on the DC bus is relatively large, the volume of the host magnetic ring 102 can be set to be larger than that of a single slave magnetic ring. By reasonably setting the host magnetic ring and the slave magnetic ring, only one host magnetic ring is needed for the power line carrier communication host circuit 101 to couple, and the design is simple; moreover, for the communication between the inverter and the combiner box, the electrical connection can also support broadcasting.

[0032] In this embodiment, the power line carrier communication host circuit 101 in the inverter can transmit the carrier signal to the combiner box through the coupling of the host magnetic ring 102, and the power line carrier communication slave circuit of the combiner box can couple the carrier signal through the slave magnetic ring to realize the communication between the inverter and the combiner box. With such a setting, it is not necessary to specially lay an RS485 communication line for the inverter and the combiner box to interact signals, which greatly reduces the communication construction cost and maintenance cost between the inverter and the combiner box. And by increasing the intensity of the carrier signal, the communication distance and stability between the inverter and the combiner box can be increased. With such a setting, compared with the wireless communication method, the signal transmission is more stable and the reliability is higher.

[0033] Example 2

[0034] Refer to Figure 3 , in an embodiment, the power line carrier communication host circuit 101 includes a carrier chip 1011, such as a power line carrier communication chip, a signal amplification circuit 1012, and an isolation transformer 1014. Among them, the output end of the carrier chip 1011 is connected to the input end of the signal amplification circuit 1012, the output end of the signal amplification circuit 1012 is connected to the primary winding of the isolation transformer 1014, and the secondary winding of the isolation transformer 1014 is connected to the coupling wire of the host magnetic ring 102.

[0035] The signal amplification circuit 1012 can be a PA (power amplifier), and the signal amplification circuit 1012 is used to amplify the carrier signal output by the carrier chip 1011.

[0036] The isolation transformer 1014 is a high-frequency transformer, which is used for voltage transformation and signal isolation.

[0037] In this embodiment, the carrier signal of the carrier chip 1011 is amplified by the signal amplification circuit 1012, passes through the isolation transformer 1014, and then is transmitted to the busbar box through magnetic ring coupling. The power line carrier communication slave circuit in the busbar box can couple the carrier signal through the slave magnetic ring to realize signal interaction between the inverter and the busbar box. With such a setting, it is not necessary to lay RS485 communication lines for signal interaction between the inverter and each busbar box, reducing the communication construction cost and maintenance cost. Moreover, using the DC bus to transmit the carrier signal, compared with wireless communication methods, the signal transmission is more stable, the signal coverage is wider, and it is more reliable. Further, the communication distance and communication stability can be increased by increasing the intensity of the carrier signal.

[0038] Example 3

[0039] Refer to Figure 2 and Figure 3 The power line carrier communication host circuit 101 further includes a filter circuit 1013. The input end of the filter circuit 1013 is connected to the primary winding of the isolation transformer 1014, and the output end of the filter circuit 1013 is connected to the input end of the carrier chip 1011. In an embodiment, the photovoltaic system further includes a filter capacitor C1; the filter capacitor C1 is connected between the positive DC bus and the negative DC bus.

[0040] The filter circuit 1013 can be a band-pass filter or other circuit structures, which is not limited here. The filter circuit 1013 is used to filter the carrier signal output by the busbar box, so that the carrier signal in a specific frequency band can be smoothly transmitted to the carrier chip 1011 in the inverter, ensuring bidirectional transmission of signals between the inverter and the busbar box.

[0041] In this embodiment, the carrier signal of the carrier chip 1011 is amplified by the signal amplification circuit 1012, then passes through the isolation transformer 1014, and is transmitted to the busbar box through magnetic ring coupling. The power line carrier communication slave circuit in the busbar box can couple the carrier signal through the slave magnetic ring to realize signal interaction between the inverter and the busbar box. Further, the power line carrier communication slave circuit in the busbar box can transmit the carrier signal to the inverter through the slave magnetic ring coupling, and then transmit it to the carrier chip 1011 through the isolation transformer 1014 and the filter circuit 1013 in the inverter, realizing the transmission of the signal from the busbar box to the inverter. With this setting, there is no need to specially lay RS485 communication lines for signal interaction between the inverter and the busbar box, which simplifies the later maintenance, greatly reduces the communication cost between the inverter and the busbar box, and compared with the wireless communication method, the signal transmission is more stable and the reliability is higher.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A photovoltaic system, characterized in that: The photovoltaic system comprises an inverter and at least one combiner box, wherein the inverter comprises a DC bus, a power line carrier communication host circuit and a host magnetic ring, and the combiner box comprises a power line carrier communication slave circuit and a slave magnetic ring; The positive output cable of the combiner box is connected to the positive DC bus, and the negative output cable of the combiner box is connected to the negative DC bus; The host magnetic ring is sleeved on the DC bus to couple the carrier signal, and the power line carrier communication host circuit is connected to the host magnetic ring; The slave magnetic ring is sleeved on the output cable of the combiner box, and the power line carrier communication slave circuit is connected to the slave magnetic ring.

2. The photovoltaic system according to claim 1, characterized in that: The power line carrier communication host circuit includes a carrier chip, a signal amplification circuit and an isolation transformer; The output end of the carrier chip is connected to the input end of the signal amplifying circuit, the output end of the signal amplifying circuit is connected to the primary winding of the isolation transformer, and the secondary winding of the isolation transformer is connected to the coupling line of the host magnetic ring.

3. The photovoltaic system according to claim 2, characterized in that: The power line carrier communication host circuit also includes a filter circuit, the input end of the filter circuit is connected to the primary winding of the isolation transformer, and the output end of the filter circuit is connected to the input end of the carrier chip.

4. The photovoltaic system according to claim 3, characterized in that: The carrier chip is a power line carrier communication chip.

5. The photovoltaic system according to claim 1, characterized in that: The host magnetic ring is sleeved on the positive DC bus.

6. The photovoltaic system according to claim 1, characterized in that: The host magnetic ring is sleeved on the negative DC bus.

7. The photovoltaic system according to claim 1, characterized in that: The slave magnetic ring is sleeved on the positive output cable of the combiner box.

8. The photovoltaic system according to claim 1, characterized in that: The slave magnetic ring is sleeved on the negative output cable of the combiner box.

9. The photovoltaic system according to any one of claims 1 to 8, characterized in that: The photovoltaic system also includes a filter capacitor; The filter capacitor is connected between the positive DC bus and the negative DC bus.

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