An interface circuit, string and system for power line communication

Abstract

The embodiment of the present application discloses an interface circuit, a string and a system for power line communication, which are used to reduce device specifications, such as safety regulations, capacitance, etc., and reduce the difficulty of design. The system includes: an inverter, an optimizer group, a capacitor, a magnetic ring, a power line and a signal line. The optimizer in the optimizer group is used to adjust the DC power output of the photovoltaic assembly connected to the optimizer. The two ends of the signal line passing through the inside of the magnetic ring are connected to the inverter, and the two ends of the power line passing through the inside of the magnetic ring are connected to the capacitor and the optimizer group respectively. Among them, the interface circuit composed of the signal line, the magnetic ring, the power line and the capacitor is used to transmit the power line communication PLC signal. The above-mentioned interface circuit can avoid the high voltage of the DC power output by the optimizer group from being introduced into the inverter to reduce the specification requirements and design difficulty of devices such as capacitors.

Description

[0001] This application is a divisional application. The application number of the original application is 201910936910.3, and the original application date is September 29, 2019. The entire content of the original application is incorporated into this application by reference. Technical Field

[0002] The present application relates to the technical field of power line communication, and in particular to an interface circuit, a string and a system applied to power line communication. Background Art

[0003] Due to the renewable and clean nature of solar energy, photovoltaic (PV) grid-connected power generation technology has developed rapidly. A solar power generation system consisting of an optimizer (also known as a shut-off device), an inverter, PV modules, power lines and other components is one of the efficient PV grid-connected solutions.

[0004] like Figure 1 As shown in FIG. 1 , a common solar power generation system is currently used. The inverter and the optimizer, and the optimizers and the optimizers (each optimizer is connected in series and then connected to the inverter) are connected through power lines, and the inverter and each optimizer (such as Figure 1 The optimizers 1 to n in the figure transmit information (such as interactive operations of business queries, command control, etc.) through power line communication (PLC). The inverter can be considered as the host of the power line communication, and the optimizer can be considered as the slave of the power line communication. Among them, power line communication can also be referred to as power line communication, carrier communication, PLC communication, etc. It refers to a special communication method that uses high-voltage power lines (usually 35kV and above voltage levels in the field of power carriers), medium-voltage power lines (referring to 10kV voltage levels) or low-voltage distribution lines (380 / 220V user lines) as information transmission media for voice or data transmission.

[0005] In other words, PLC communication is essentially a way to modulate network signals (also called PLC signals) onto power lines and use existing power lines to solve network wiring problems. For the inverter to send PLC signals to the power line or receive PLC signals from the power line, a coupling device is required. At present, the coupling device generally adopts the capacitor direct coupling method, and its main implementation principle is that the inverter modulates the PLC signal and directly connects it to the power line through the capacitor. However, this capacitor direct coupling method not only has strict requirements on the selection of capacitors (for example, it needs to meet the impedance requirements of the PLC signal on the power line and cannot cause excessive attenuation of the PLC signal), but also because the voltage difference between the two power lines connected to the inverter can reach up to 1500V, so the selection of capacitors also needs to meet safety requirements to reduce the impact on the modulation circuit inside the inverter. Summary of the invention

[0006] The embodiments of the present application provide an interface circuit, a string, and a system for power line communication. The interface circuit, a string, a device, and a system for power line communication are formed by magnetic ring coupling. The high voltage between the positive and negative poles of the direct current generated by the optimizer group connected to the interface circuit will not be introduced into the modulation circuit inside the inverter connected to the interface circuit. Only the PLC signal generated by the optimizer enters the modulation circuit inside the inverter through the power line and the signal line (or the PLC signal generated by the modulation circuit inside the inverter enters the optimizer through the signal line and the power line), thereby reducing the specification requirements and design difficulty of components such as capacitors, while improving safety performance.

[0007] In view of this, the first aspect of an embodiment of the present application provides a system for power line communication, specifically including: the system includes an inverter, at least one optimizer group, at least one capacitor, a magnetic ring, a power line, and a signal line, wherein the number of optimizer groups and the number of capacitors may be the same or different, and is not limited here. It should be noted that each of the at least one optimizer group includes one or more optimizers and one or more photovoltaic modules, each optimizer is connected to each photovoltaic module in a one-to-one correspondence, and is used to convert the direct current output by each photovoltaic module into adjustable direct current, and the one or more optimizers are connected in series with at least one capacitor through a power line (for example, if the number of optimizer groups is the same as the number of capacitors, each optimizer group composed of one or more optimizers is connected in series with each capacitor in a one-to-one correspondence); thereafter, the power line connected to any one end of the at least one capacitor passes through the inside of the magnetic ring, that is, after the optimizers in each optimizer group are connected in series, they are connected to the two ends of each capacitor through the power line, and finally, the signal line passes through the inside of the magnetic ring and is connected to the inverter, and the signal line, power line, magnetic ring and capacitor are used to transmit the PLC signal generated by the inverter and / or at least one optimizer.

[0008] In the above-mentioned embodiment of the present application, by means of magnetic ring coupling, the high voltage between the positive and negative poles of the DC power generated on the optimizer group will not be introduced into the interior of the inverter. Only the PLC signal generated on the optimizer enters the interior of the inverter through the power line and the signal line (or the PLC signal generated in the inverter enters the interior of the optimizer through the signal line and the power line). Therefore, there are no safety regulations, capacitance and other requirements for the design of the modulation circuit inside the inverter, which reduces the design requirements and improves the safety performance.

[0009] In combination with the first aspect of the embodiments of the present application, in a first implementation manner of the first aspect of the embodiments of the present application, at least one optimizer group in the system specifically includes an optimizer group, then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: the power line connected to the DC positive output end of the optimizer group passes through the inside of the magnetic ring.

[0010] In combination with the first aspect of the embodiments of the present application, in the second implementation manner of the first aspect of the embodiments of the present application, at least one optimizer group in the system specifically includes an optimizer group, then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: the power line connected to the negative DC power output end of the optimizer group passes through the inside of the magnetic ring.

[0011] In the above embodiments of the present application, the system includes only one optimizer group, and the power line connecting the negative output terminal or the positive output terminal of the DC power of the optimizer group passes through the inside of the magnetic ring. The above embodiments of the present application specifically explain how the power line passes through the inside of the magnetic ring when there is only one optimizer group, which is diverse.

[0012] In combination with the first aspect of the embodiments of the present application, in a third implementation manner of the first aspect of the embodiments of the present application, at least one optimizer group in the system specifically includes multiple optimizer groups (e.g., two or more), then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: a power line connecting the positive pole of the DC output end of each optimizer group passing through the inside of the magnetic ring.

[0013] In combination with the first aspect of the embodiments of the present application, in a fourth implementation manner of the first aspect of the embodiments of the present application, at least one optimizer group in the system specifically includes multiple optimizer groups (e.g., two or more), then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: a power line connecting the negative pole of the DC output end of each optimizer group passing through the inside of the magnetic ring.

[0014] In combination with the first aspect of the embodiments of the present application, in the fifth implementation manner of the first aspect of the embodiments of the present application, at least one optimizer group in the system specifically includes multiple optimizer groups (e.g., two or more), then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: a power line connected to the positive pole of the DC output end of the first optimizer group and a power line connected to the negative pole of the DC power of the second optimizer group passing through the inside of the magnetic ring, wherein the first optimizer group and the second optimizer group are two different optimizer groups among the above-mentioned multiple optimizer groups.

[0015] In the above embodiments of the present application, the system includes multiple (e.g., two or more) optimizer groups, then the power lines connecting the DC positive output terminals of these optimizer groups all pass through the inside of the magnetic ring, or the power lines connecting the DC negative output terminals of these optimizer groups all pass through the inside of the magnetic ring, or the power lines connecting the DC negative output terminals or positive output terminals of these optimizer groups pass through the inside of the magnetic ring in a mixed manner. The above embodiments of the present application specifically describe how the power lines pass through the inside of the magnetic ring when there are multiple optimizer groups, and provide a variety of ways to pass through the inside of the magnetic ring, with flexibility and selectivity.

[0016] The second aspect of the embodiment of the present application provides an interface circuit for power line communication, which may include: at least one capacitor, a magnetic ring, a power line and a signal line. The power line is respectively connected to both ends of at least one capacitor, and the power line port connected to one end of each capacitor constitutes a first interface, and the power line port connected to the other end of each capacitor constitutes a second interface, the first interface and the second interface are used to connect the optimizer, and the power line connected to either end of each capacitor passes through the inside of the magnetic ring; at the same time, the signal line also passes through the inside of the magnetic ring, and the two ports of the signal line constitute a third interface and a fourth interface respectively, and the third interface and the fourth interface are used to connect the inverter; the interface circuit is used to transmit the PLC signal generated by the optimizer and / or the inverter.

[0017] In combination with the second aspect of the embodiments of the present application, in a first implementation of the second aspect of the embodiments of the present application, the interface circuit further includes: an inverter connected to the third interface and the fourth interface.

[0018] In the above-mentioned embodiment of the present application, an interface circuit applied to power line communication is specifically described, so that the high voltage between the positive and negative poles of the DC power generated on the optimizer group connected to the interface circuit will not be introduced into the modulation circuit inside the inverter connected to the interface circuit. Only the PLC signal generated on the optimizer enters the modulation circuit inside the inverter through the power line and the signal line (or the PLC signal generated on the modulation circuit inside the inverter enters the optimizer through the signal line and the power line), thereby reducing the specification requirements and design difficulty of components such as capacitors, while improving safety performance.

[0019] A third aspect of an embodiment of the present application provides a group string for power line communication, which, in addition to the interface circuit of the second aspect of the embodiment of the present application described above, also includes: at least one optimizer group, each of the at least one optimizer group being composed of a plurality of optimizers connected in series, and the two ends of each optimizer group being respectively connected to the first interface and the second interface of the above-mentioned interface circuit.

[0020] In combination with the third aspect of the embodiments of the present application, in the first implementation of the third aspect of the embodiments of the present application, the string may further include: a photovoltaic module connected to each optimizer, and the optimizer is used to convert the direct current output by the photovoltaic module into adjustable direct current.

[0021] In the above-mentioned embodiment of the present application, a group string applied to power line communication is specifically described, and each optimizer group in the group string is connected one by one to each of the above-mentioned capacitors through a first interface and a second interface. In this way, the PLC signal generated by the optimizer on each optimizer group can be transmitted through the power line, signal line, magnetic ring and corresponding capacitor.

[0022] The fourth aspect of the embodiments of the present application provides a device for power line communication, which includes the string described in any one of the third aspect of the embodiments of the present application and the first implementation of the third aspect. In addition, the device also includes an inverter, which can be connected to the third interface and the fourth interface respectively. At this time, the power line, signal line, magnetic ring and at least one capacitor are used to transmit the PLC signal generated in the inverter and / or optimizer, wherein the capacitor exists as a signal channel.

[0023] In the above embodiments of the present application, by means of magnetic ring coupling, the high voltage between the positive and negative poles of the DC power generated on the optimizer group will not be introduced into the interior of the inverter. Only the PLC signal generated on the optimizer enters the interior of the inverter through the power line and the signal line (or the PLC signal generated in the inverter enters the interior of the optimizer through the signal line and the power line), thereby reducing the specification requirements and design difficulty of components such as capacitors, while improving safety performance.

[0024] In combination with the fourth aspect of the embodiments of the present application, in the first implementation manner of the fourth aspect of the embodiments of the present application, at least one optimizer group in the device specifically includes an optimizer group, then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: the power line connected to the DC positive output end of the optimizer group passes through the inside of the magnetic ring.

[0025] In combination with the fourth aspect of the embodiments of the present application, in the second implementation manner of the fourth aspect of the embodiments of the present application, at least one optimizer group in the device specifically includes an optimizer group, then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: the power line connected to the negative DC power output end of the optimizer group passes through the inside of the magnetic ring.

[0026] In the above embodiments of the present application, the device includes only one optimizer group, and the power line connecting the negative output terminal or the positive output terminal of the DC power of the optimizer group passes through the inside of the magnetic ring. The above embodiments of the present application specifically explain how the power line passes through the inside of the magnetic ring when there is only one optimizer group, which is diverse.

[0027] In combination with the fourth aspect of the embodiments of the present application, in a third implementation manner of the fourth aspect of the embodiments of the present application, at least one optimizer group in the device specifically includes multiple optimizer groups (e.g., two or more), then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: a power line connected to the negative pole of the DC output end of each optimizer group passing through the inside of the magnetic ring.

[0028] In combination with the fourth aspect of the embodiments of the present application, in a fourth implementation manner of the fourth aspect of the embodiments of the present application, at least one optimizer group in the device specifically includes multiple optimizer groups (such as two or more), then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: the power line connected to the negative pole of the DC power of each optimizer group in the multiple optimizer groups passes through the inside of the magnetic ring.

[0029] In combination with the fourth aspect of the embodiments of the present application, in a fifth implementation manner of the fourth aspect of the embodiments of the present application, at least one optimizer group in the device specifically includes multiple optimizer groups (e.g., two or more), then the power line connected to any end of at least one capacitor passing through the inside of the magnetic ring specifically includes: a power line connected to the positive pole of the DC output end of the first optimizer group and a power line connected to the negative pole of the DC power of the second optimizer group passing through the inside of the magnetic ring, wherein the first optimizer group and the second optimizer group are two different optimizer groups among the above-mentioned multiple optimizer groups.

[0030] In the above embodiments of the present application, the device includes multiple (e.g., two or more) optimizer groups, and the power lines connecting the DC positive output terminals of these optimizer groups all pass through the inside of the magnetic ring, or the power lines connecting the DC negative output terminals of these optimizer groups all pass through the inside of the magnetic ring, or the power lines connecting the DC negative output terminals or positive output terminals of these optimizer groups pass through the inside of the magnetic ring in a mixed manner. The above embodiments of the present application specifically describe how the power lines pass through the inside of the magnetic ring when there are multiple optimizer groups, and provide a variety of ways to pass through the inside of the magnetic ring, which are flexible and selectable.

[0031] A fifth aspect of the embodiments of the present application further provides a system for power line communication, which may specifically include:

[0032] Inverter, optimizer group, capacitor, magnetic ring, power line, signal line; wherein, both ends of the signal line passing through the magnetic ring are connected to the inverter, and both ends of the power line passing through the magnetic ring are respectively connected to the capacitor and the optimizer group; the magnetic ring, the signal line, the power line and the capacitor are used to transmit power line communication PLC signals, wherein the optimizer group includes one optimizer or multiple optimizers connected in series; the optimizer group is used to connect photovoltaic modules and adjust the DC power output by the photovoltaic modules.

[0033] In the above embodiments of the present application, by means of magnetic ring coupling, the high voltage between the positive and negative poles of the DC power generated on the optimizer group will not be introduced into the interior of the inverter. Only the PLC signal generated on the optimizer enters the interior of the inverter through the power line and the signal line (or the PLC signal generated in the inverter enters the interior of the optimizer through the signal line and the power line), thereby reducing the specification requirements and design difficulty of components such as capacitors, while improving safety performance.

[0034] In combination with the fifth aspect of the embodiments of the present application, in a first implementation manner of the fifth aspect of the embodiments of the present application, both ends of the signal line passing through the magnetic ring are connected to the inverter, and both ends of the power line passing through the magnetic ring are respectively connected to the capacitor and the optimizer group, specifically including: both ends of the first signal line passing through the first magnetic ring are connected to the inverter, and both ends of the first power line passing through the first magnetic ring are respectively connected to the first capacitor and the first optimizer group; both ends of the second signal line passing through the second magnetic ring are connected to the inverter, and both ends of the second power line passing through the second magnetic ring are respectively connected to the second capacitor and the second optimizer group.

[0035] In the above-mentioned embodiments of the present application, when there are multiple magnetic rings, the specific connection relationship between the optimizer group, the capacitor and the multiple magnetic rings is specifically explained, which has flexibility.

[0036] In combination with the fifth aspect of the embodiments of the present application, in a second implementation manner of the fifth aspect of the embodiments of the present application, both ends of the signal line passing through the magnetic ring are connected to the inverter, and both ends of the power line passing through the magnetic ring are respectively connected to the capacitor and the optimizer group, specifically including: both ends of the signal line passing through the magnetic ring are connected to the inverter, both ends of the first power line passing through the magnetic ring are respectively connected to the first capacitor and the first optimizer group, and both ends of the second power line passing through the magnetic ring are respectively connected to the second capacitor and the second optimizer group.

[0037] In the above-mentioned embodiments of the present application, when there is a magnetic ring, the specific connection relationship between the optimizer group, the capacitor and the magnetic ring is specifically described, which has flexibility.

[0038] In combination with the second implementation manner of the fifth aspect of the embodiments of the present application, in the third implementation manner of the fifth aspect of the embodiments of the present application, the two ends of the first power line passing through the magnetic ring are respectively connected to the first capacitor and the first optimizer group, and the two ends of the second power line passing through the magnetic ring are respectively connected to the second capacitor and the second optimizer group, specifically including: the first power line is connected to the positive pole of the direct current output of the first optimizer group, and the second power line is connected to the negative pole of the direct current output of the second optimizer group.

[0039] In the above-mentioned embodiment of the present application, a specific connection method between the capacitor and the multiple optimizer groups when there are multiple optimizer groups is specifically described, which has flexibility.

[0040] In combination with the second implementation manner of the fifth aspect of the embodiments of the present application, in the fourth implementation manner of the fifth aspect of the embodiments of the present application, the two ends of the first power line passing through the magnetic ring are respectively connected to the first capacitor and the first optimizer group, and the two ends of the second power line passing through the magnetic ring are respectively connected to the second capacitor and the second optimizer group, specifically including: the first power line is connected to the positive pole of the direct current output of the first optimizer group, and the second power line is connected to the positive pole of the direct current output of the second optimizer group; or, the first power line is connected to the negative pole of the direct current output of the first optimizer group, and the second power line is connected to the negative pole of the direct current output of the second optimizer group.

[0041] In the above-mentioned embodiment of the present application, another specific connection method between the capacitor and the multiple optimizer groups when there are multiple optimizer groups is specifically described, which is optional.

[0042] The sixth aspect of the embodiments of the present application provides an interface circuit for power line communication, which may specifically include: a magnetic ring, a signal line, a power line and a capacitor; the port of the first power line connected to one end of the capacitor constitutes a first interface, and the port of the second power line connected to the other end of the capacitor constitutes a second interface, and the first power line or the second power line passes through the magnetic ring; the two ends of the signal line passing through the magnetic ring constitute a third port and a fourth port respectively; wherein the first port and the second port are used to connect to an optimizer; the third port and the fourth port are used to connect to an inverter; and the interface circuit is used to transmit PLC signals.

[0043] In the above-mentioned embodiment of the present application, an interface circuit applied to power line communication is specifically described, so that the high voltage between the positive and negative poles of the DC power generated on the optimizer group connected to the interface circuit will not be introduced into the modulation circuit inside the inverter connected to the interface circuit. Only the PLC signal generated on the optimizer enters the modulation circuit inside the inverter through the power line and the signal line (or the PLC signal generated on the modulation circuit inside the inverter enters the optimizer through the signal line and the power line), thereby reducing the specification requirements and design difficulty of components such as capacitors, while improving safety performance.

[0044] The seventh aspect of the embodiment of the present application also provides an inverter for power line communication, which may specifically include: a magnetic ring, a signal line, a power line and a capacitor; the power line port connected to one end of the capacitor constitutes a first interface, and the power line port connected to the other end of the capacitor constitutes a second interface; wherein the first port and the second port are used to connect an optimizer; and the interface circuit is used to transmit PLC signals.

[0045] The eighth aspect of the embodiment of the present application also provides a group string applied to power line communication, which, in addition to the interface circuit as described in the sixth aspect of the embodiment of the present application, also includes: an optimizer group, the optimizer group including one optimizer or multiple optimizers connected in series, wherein the two ends of the optimizer group are respectively connected to the first interface and the second interface of the above-mentioned interface circuit.

[0046] In combination with the eighth aspect of the embodiments of the present application, in a first implementation of the eighth aspect of the embodiments of the present application, the string may further include: a photovoltaic module connected to each optimizer, and the optimizer is used to adjust the DC power output by the photovoltaic module.

[0047] In the above-mentioned embodiment of the present application, a group string applied to power line communication is specifically described, and each optimizer group in the group string is connected one by one to each of the above-mentioned capacitors through a first interface and a second interface. In this way, the PLC signal generated by the optimizer on each optimizer group can be transmitted through the power line, signal line, magnetic ring and corresponding capacitor.

[0048] The ninth aspect of the embodiments of the present application also provides a device for power line communication, which includes the string described in any one of the eighth aspect of the embodiments of the present application and the first implementation of the eighth aspect. In addition, the device also includes an inverter, which can be connected to the third interface and the fourth interface respectively. At this time, the power line, signal line, magnetic ring and capacitor are used to transmit the PLC signal generated in the inverter and / or optimizer, wherein the capacitor exists as a signal channel.

[0049] It can be seen from the above technical scheme that an interface circuit for power line communication provided in the embodiment of the present application includes: at least one capacitor, a magnetic ring, a power line and a signal line. The power lines are respectively connected to the two ends of the at least one capacitor, wherein the power line port connected to one end of the at least one capacitor constitutes a first interface, and the power line port connected to the other end of the at least one capacitor constitutes a second interface. For example, if there is one capacitor (called C1), the power lines are respectively connected to the two ends of the capacitor C1, wherein the interface of the power line at one end is the first interface, and the interface of the power line at the other end is the second interface; for example, if there are three capacitors (called C2, C3, C4), the power lines are respectively connected to the two ends of the three capacitors, wherein the interfaces of the power lines at one end of C2, C3, and C4 can be called the first interface, and the interfaces of the power lines at the other end of C2, C3, and C4 can be called the second interface. In addition, the power line connected to any end of the at least one capacitor passes through the inside of the magnetic ring, and similarly, the signal line also passes through the inside of the magnetic ring, and the two ports of the signal line constitute the third interface and the fourth interface respectively. The interface circuit is applied to power line communication, the first interface and the second interface can be further connected to the optimizer group (the optimizer in the optimizer group is connected to the photovoltaic module), and the third interface and the fourth interface can be further connected to the inverter, so that the power line, the signal line, the magnetic ring, and at least one capacitor can be used to transmit the PLC signal generated by the optimizer and / or the inverter. In the embodiment of the present application, the interface circuit applied to power line communication is formed by magnetic ring coupling, and the high voltage between the positive and negative poles of the DC generated by the optimizer group connected to the interface circuit will not be introduced into the modulation circuit inside the inverter connected to the interface circuit. Only the PLC signal generated by the optimizer enters the modulation circuit inside the inverter through the power line and the signal line (or the PLC signal generated by the modulation circuit inside the inverter enters the optimizer through the signal line and the power line), thereby reducing the specification requirements and design difficulty of devices such as capacitors, while improving safety performance, and, because only one magnetic ring is involved, the cost of the entire solar power generation system is further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic diagram of a common solar power generation system;

[0051] Figure 2 It is a schematic diagram of the capacitor direct coupling method commonly used in solar power generation systems for transmitting PLC signals;

[0052] Figure 3 A schematic diagram of a system applied to power line communication in an embodiment of the present application;

[0053] Figure 4Another schematic diagram of a system applied to power line communication in an embodiment of the present application;

[0054] Figure 5 Another schematic diagram of a system applied to power line communication in an embodiment of the present application;

[0055] Figure 6 Another schematic diagram of a system applied to power line communication in an embodiment of the present application;

[0056] Figure 7 Another schematic diagram of a system applied to power line communication in an embodiment of the present application;

[0057] Figure 8 A schematic diagram of an interface circuit applied to power line communication in an embodiment of the present application;

[0058] Fig. 9 is another schematic diagram of an interface circuit applied to power line communication in an embodiment of the present application;

[0059] Fig.10 is another schematic diagram of an interface circuit applied to power line communication in an embodiment of the present application;

[0060] Fig.11 A schematic diagram of a group string applied to power line communication in an embodiment of the present application;

[0061] Fig.12 Another schematic diagram of a group string applied to power line communication in an embodiment of the present application. DETAILED DESCRIPTION

[0062] The embodiments of the present application provide an interface circuit, a string and a system for power line communication. The interface circuit for power line communication is formed by magnetic ring coupling. In this way, the high voltage between the positive and negative poles of the DC power generated on the optimizer group connected to the interface circuit will not be introduced into the modulation circuit inside the inverter connected to the interface circuit. Only the PLC signal generated on the optimizer enters the modulation circuit inside the inverter through the power line and the signal line (or the PLC signal generated on the modulation circuit inside the inverter enters the optimizer through the signal line and the power line). Therefore, the specification requirements and design difficulty of components such as capacitors are reduced, while the safety performance is improved. Moreover, since only one magnetic ring is involved, the cost of the entire solar power generation system is further reduced.

[0063] Before introducing this embodiment, the concepts that may appear in the embodiments of this application are first introduced. It should be understood that the explanation of the relevant concepts may be limited due to the specific circumstances of the embodiments of this application, but it does not mean that this application is limited to the specific circumstances. The specific circumstances of different embodiments may also be different, which is not specifically limited here.

[0064] The solar power generation system consists of optimizers (also called shut-off devices), inverters, PV modules, power lines and other components. Among them, PV modules are the core components and are used to convert sunlight into electrical energy (generally direct current). Since they are greatly affected by light radiation, the direct current converted will be high when the auxiliary light radiation is strong and the radiation time is long (such as in summer). On the contrary, the direct current converted will be low when the auxiliary light radiation is weak and the radiation time is short (such as on cloudy days). For example, if there are obstructions blocking the PV modules, the power generation of the PV modules will be significantly reduced. At the same time, since the voltage generated on the power line after the PV modules are connected in series is very high, in dangerous situations such as fire, there needs to be a way to reduce the voltage after the PV modules are connected in series to protect personal safety. Based on the above, optimizers came into being. Optimizers can also be called circuit breakers. They are devices used to convert the DC power generated by PV modules into adjustable DC power (i.e., the DC power output by PV modules is converted from DC to DC to output DC power with adjustable voltage and current). They are used to achieve dynamic control of the DC power generated by PV modules. For example, when there is shading, the output power of a certain PV module (i.e., the shaded PV module) among the multiple PV modules connected in series will be unstable. If there is no optimizer, the current value on the power line of the entire PV module connected in series will be pulled down to the current value output by the shaded PV module (i.e., the minimum current value), thereby resulting in a waste of resources. The function of the optimizer is to balance the output power of each PV module so that the overall output power on the power line is stable. In addition, the optimizer can also shut down the output of the corresponding connected PV module in an emergency to reduce safety hazards. The inverter is a DC-to-AC power source, which converts the adjustable DC power output by the optimizer into AC power. The inverter and optimizer are connected by a power line, and information is transmitted through the power line, including business query, command control and other information interaction operations.

[0065] In addition, the power line communication method currently commonly used in solar power generation systems will be further introduced, namely the capacitor direct coupling method. Its main implementation principle is that the inverter modulates the PLC signal and directly connects it to the power line through the capacitor. Figure 2 As shown ( Figure 2The PV components are not shown in the figure), the optimizer group 11 formed by at least one optimizer (e.g., it can be one optimizer, or two or more optimizers, which is not limited here) connected in series is connected to one end of two capacitors C11 and C12 (because the PLC signal is a differential signal, in some implementations, only one of the capacitors C11 or C12 may be used) through power lines, and the other ends of C11 and C12 are connected to the modulation circuit in the inverter. It should be noted that multiple other optimizer groups similar to the optimizer group 11 (such as Figure 2 The optimizer groups 12, ..., optimizer 1n) in the inverter are connected to the modulation circuit of the inverter to realize the inverter's control over multiple optimizer groups. However, this capacitor direct coupling method not only has strict requirements on the selection of capacitors (for example, it needs to meet the impedance requirements of the PLC signal on the power line and cannot cause excessive attenuation of the PLC signal), but also because the voltage difference between the two power lines connected to the inverter can reach up to 1500V, the capacitor coupling method will also introduce DC high voltage into the modulation circuit of the inverter (the modulation circuit is used to send PLC signals), thereby raising the requirements for the wiring method and component selection of the modulation circuit of the inverter, increasing the cost of the modulation circuit in the inverter, and when there are multiple signals (such as Figure 2 When the optimizer 11, the optimizer group 12, ..., the optimizer 1n in the embodiment need to be coupled, a plurality of capacitors for coupling are also required (such as Figure 2 The capacitors C11, C12, C21, C22, ..., Cn1, Cn2) in the circuit are used, thereby further increasing the cost.

[0066] Based on this, in order to solve the above-mentioned problems brought about by the capacitive coupling method, an embodiment of the present application first provides a system for power line communication, the system comprising an inverter, at least one optimizer group, at least one capacitor, a magnetic ring, a power line, and a signal line, wherein the number of optimizer groups and the number of capacitors may be the same or different. It should be noted that each of the at least one optimizer group includes one or more optimizers and one or more photovoltaic modules, each optimizer is connected to each photovoltaic module in a one-to-one correspondence, and is used to convert the direct current output by each photovoltaic module into adjustable direct current, and the one or more optimizers are connected in series with at least one capacitor through a power line (for example, if the number of optimizer groups is the same as the number of capacitors, each optimizer group composed of one or more optimizers is connected in series with each capacitor in a one-to-one correspondence); thereafter, the power line connected to any one end of the at least one capacitor passes through the inside of the magnetic ring, that is, after the optimizers in each optimizer group are connected in series, they are connected to the two ends of each capacitor through the power line, and finally, the signal line passes through the inside of the magnetic ring and is connected to the inverter, and the signal line, power line, magnetic ring and capacitor are used to transmit the PLC signal generated by the inverter and / or at least one optimizer.

[0067] In the embodiment of the present application, since there can be one or more optimizer groups, there are also one or more corresponding capacitors. Various situations are described below.

[0068] 1. The system includes an optimizer group and a capacitor.

[0069] like Figure 3 As shown, when the system includes only one optimizer group A (the optimizer group A includes at least one optimizer, each optimizer is connected to a corresponding PV module, Figure 3 When the optimizer group A is connected to the two ends of the capacitor C31, a voltage is generated, wherein: Figure 3 The power line connecting the DC positive output terminal of optimizer group A is represented by a solid line, and the power line connecting the DC negative output terminal of optimizer group A is represented by a dotted line. Then, the power line (i.e., the solid line) connecting the DC positive output terminal of optimizer group A passes through the inside of the magnetic ring, such as Figure 3 Of course, the power line (ie, the dotted line) connected to the negative DC output terminal of the optimizer group A may also pass through the inside of the magnetic ring, which is not limited here.

[0070] 2. The system includes at least two optimizer groups and at least two capacitors.

[0071] like Figure 4 As shown, when the system includes multiple optimizer groups (two or more, each optimizer group includes at least one optimizer, and each optimizer is connected to a PV module. Figure 4 PV modules are not shown), each optimizer group can be Figure 3 After connecting in a similar way, connect to the inverter, as shown below: Figure 4 As shown, Figure 4 It is illustrated that the power line connecting the DC positive output terminal of each optimizer group passes through the inside of each magnetic ring. In fact, the power line connecting the DC negative output terminal of each optimizer group can also pass through the inside of each magnetic ring, which is not elaborated here.

[0072] In addition, in addition to Figure 4 In the above manner, when the system includes at least two optimizer groups and at least two capacitors, the system can also be Figure 5 As shown, Figure 5 At least two optimizer groups (each optimizer group includes at least one optimizer, each optimizer is connected to a PV module, Figure 5 When the PV components are not shown in the figure, a voltage will be generated at both ends of the capacitor corresponding to each optimizer group, where Figure 5The power line connecting the DC positive output terminal of each optimizer group is represented by a solid line, and the power line connecting the DC negative output terminal of each optimizer group is represented by a dotted line. Then, the power line (i.e., the solid line) connecting the DC positive output terminal of each optimizer group passes through the inside of the magnetic ring, such as Figure 5 This is the situation shown. Figure 5 The situation shown including at least two optimizer groups allows the PLC signal to be coupled to the power lines of multiple optimizer groups at the same time, but this coupling method has certain current requirements on the magnetic ring, that is, the influence of the sum of the currents on multiple optimizer groups must not cause the magnetic ring to saturate.

[0073] It should be noted that in some embodiments of the present application, the power line connecting the DC negative output terminal of each optimizer group may pass through the inside of the magnetic ring, such as Figure 6 As shown, the power line (i.e., the dotted line) connecting the DC negative output terminal of each optimizer group passes through the inside of the magnetic ring.

[0074] It should also be noted that in some embodiments of the present application, the power line connecting the positive pole of the DC output terminal of the first optimizer group and the power line connecting the negative pole of the DC output terminal of the second optimizer group may pass through the inside of the magnetic ring, wherein the first optimizer group and the second optimizer group are two different optimizer groups among the above-mentioned multiple optimizer groups. Figure 7 As shown (schematically showing three optimizer groups), the power line (i.e., solid line) connecting the DC positive output terminal of one optimizer group passes through the inside of the magnetic ring, and the power line (i.e., dotted line) connecting the DC negative output terminals of two optimizer groups passes through the inside of the magnetic ring; in some embodiments of the present application, the power line (i.e., solid line) connecting the DC positive output terminals of the two optimizer groups may pass through the inside of the magnetic ring, and the power line (i.e., dotted line) connecting the DC negative output terminal of one optimizer group may pass through the inside of the magnetic ring, as long as the power lines passing through the inside of the magnetic ring include both the power line connecting the DC negative output terminal of the optimizer group and the power line connecting the DC positive output terminal of the optimizer group, and no specific limitation is made here.

[0075] The above-mentioned method of mixing the power lines connecting the DC positive output terminal or the negative output terminal of the optimizer group through the magnetic ring can reduce the requirements for the magnetic ring current. Because the influence of the magnetic ring current mainly comes from the large attenuation of the magnetic ring magnetic permeability caused by the bias generated by the current. For example, assuming that there are 6 optimizer groups in the system that need to be connected to the inverter, the power lines connecting the DC positive output terminals of the 1st, 2nd, and 3rd optimizer groups and the power lines connecting the DC negative output terminals of the 4th, 5th, and 6th optimizer groups can be passed through the magnetic ring together. Since the current on the power line connecting the DC positive output terminal of the 1st, 2nd, and 3rd optimizer groups is opposite to the current on the power line connecting the DC negative output terminal of the 4th, 5th, and 6th optimizer groups, the direction of the magnetic flux generated by each is also opposite, and the superposition will cancel each other out, thereby greatly reducing the bias effect on the magnetic ring.

[0076] In addition, an embodiment of the present application further provides an interface circuit, which is applied to power line communication, and the interface circuit may include: at least one capacitor, a magnetic ring, a power line, and a signal line. Since the number of capacitors included in the interface circuit is different, the following describes several cases respectively.

[0077] 1. The interface circuit includes a capacitor, a magnetic ring, a power line and a signal line.

[0078] If the interface circuit only includes one capacitor C31, then the connection diagram of the capacitor C31, the magnetic ring, the power line, and the signal line is as follows: Figure 8 As shown: the power lines are respectively connected to the two ends of the capacitor C31, wherein the power line port connected to one end of the capacitor C31 constitutes a first interface P1, and the power line port connected to the other end of the capacitor C31 constitutes a second interface P2. The power line ( Figure 8 As shown in FIG. 1 , the power line constituting the first interface P1 passes through the inside of the magnetic ring, and the signal line also passes through the inside of the magnetic ring. One port of the signal line constitutes the third interface P3, and the other port of the signal line constitutes the fourth interface P4.

[0079] 2. The interface circuit includes at least two capacitors, a magnetic ring, a power line and a signal line.

[0080] If the interface circuit includes at least two capacitors, take three capacitors as an example, the three capacitors are C41, C42, and C43, then the connection diagram of the three capacitors and the magnetic ring, power line, and signal line is as follows: Fig. 9As shown in FIG. 1 , the power line is connected to both ends of the capacitors C41, C42, and C43, respectively. The power line ports connected to one end of the capacitors C41, C42, and C43 constitute three first interfaces, which can be respectively referred to as P11, P12, and P13. The power line ports connected to the other ends of the capacitors C41, C42, and C43 constitute three second interfaces, which can be respectively referred to as P21, P22, and P23. The power line ( Fig. 9 As shown in the figure, the power lines constituting the three first interfaces P11, P12, and P13 pass through the inside of the magnetic ring, and the signal line also passes through the inside of the magnetic ring. One port of the signal line constitutes the third interface P31, and the other port of the signal line constitutes the fourth interface P41.

[0081] It should be noted that, in some embodiments of the present application, the interface circuit may further include an inverter, which is connected to the magnetic ring via the third interface and the fourth interface. Therefore, the PLC signal generated by the inverter can be transmitted via the power line, the magnetic ring and at least one capacitor of the interface circuit. Fig.10 Take this as an example to illustrate: Fig.10 The illustrated interface circuit includes a capacitor, that is, Figure 8 On the basis of the illustrated interface circuit, the third interface P3 and the fourth interface P4 are connected to the modulation circuit inside the inverter, so that the PLC signal generated by the modulation circuit inside the inverter can be coupled to the power line through the signal line and the magnetic ring. Fig. 9 Based on the illustrated interface circuit, the third interface P31 and the fourth interface P41 of the interface circuit are also connected to the modulation circuit inside the inverter in a similar manner, which will not be described in detail here.

[0082] In addition to providing an interface circuit for power line communication, the embodiment of the present application also provides a string, which is also used for power line communication, and the string may include the above Figures 8 to 9 The interface circuit described in any one of the above, in addition, the string also includes at least one optimizer group, the number of the at least one optimizer group is the same as the number of at least one capacitor in the above interface circuit, and each optimizer group in the at least one optimizer group is composed of at least one optimizer connected in series (connected in series through a power line), and each optimizer group is connected to each of the above capacitors in a one-to-one correspondence through a first interface and a second interface, so that the PLC signal generated by the optimizer on each optimizer group can be transmitted through the power line, the signal line, the magnetic ring and the corresponding capacitor. Since the number of optimizer groups contained in the string is different, several cases are introduced below.

[0083] 1. The string includes an optimizer group

[0084] When the string includes only one optimizer group, the corresponding interface circuit includes only one capacitor, such as Fig.11 As shown, each optimizer in the optimizer group A in the string is connected in series through the power line, and then through the first interface P1 and the second interface P2 ( Fig.11 (not shown) is connected to the capacitor C31.

[0085] 2. The string includes at least two optimizer groups

[0086] When the string includes at least two optimizer groups, the corresponding interface circuit also includes the same number of capacitors as the optimizer groups, such as Fig.12 As shown, the number of optimizer groups is 3 for example. The 3 optimizer groups are respectively called optimizer group B, optimizer group C, and optimizer group D. Then the number of corresponding capacitors is also 3 (such as Fig. 9 As shown), optimizer group B, optimizer group C, and optimizer group D are respectively Figure 4 The capacitors C41, C42, and C43 are connected one by one (the first interfaces P11, P12, and P13 and the second interfaces P21, P22, and P23 are connected in a one-to-one manner). Fig.12 not shown).

[0087] It should be noted that, in some embodiments of the present application, in addition to at least one optimizer group, the string also includes at least one PV module, wherein the number of PV modules is the same as the number of all optimizers in at least one optimizer group, and each PV module is connected to each optimizer one by one, that is, one optimizer is connected to one PV module, for regulating the direct current generated by the corresponding PV module, that is, converting the direct current output of each PV module into adjustable direct current.

[0088] In addition to providing an interface circuit and a string for power line communication, the embodiment of the present application will also provide a device, which is also applied to power line communication. The device includes the above Figure 11 to Figure 12 At least one string as described in any one of the above, in addition, the device also includes an inverter, which can be connected to the magnetic ring through a third interface and a fourth interface respectively, at which time the power line, the signal line, the magnetic ring and at least one capacitor are used to transmit the PLC signal generated in the inverter and / or the optimizer, wherein the capacitor exists as a signal channel. In an embodiment of the present application, there can be one or more strings, and there can also be one or more optimizer groups in each string. Various situations are described below.

[0089] 1. A situation where the device includes a group string, and the group string includes an optimizer group.

[0090] With the above Figure 3 Similarly, when the device includes only one string, and the string includes only one optimizer group A, the optimizer group A is connected to both ends of the capacitor C31 to generate a voltage, wherein, Figure 3 In the figure, the power line connected to the DC positive output terminal of optimizer group A is represented by a solid line, and the power line connected to the DC negative output terminal of optimizer group A is represented by a dotted line, so the power line (i.e., the solid line) connected to the DC positive output terminal of optimizer group A passes through the inside of the magnetic ring. Of course, the power line (i.e., the dotted line) connected to the DC negative output terminal of optimizer group A can also pass through the inside of the magnetic ring, which is not limited here.

[0091] 2. The device includes at least two strings, each of which includes an optimizer group.

[0092] With the above Figure 4 Similarly, when the device includes multiple strings (two or more), and each string includes only one optimizer group, each string can be configured in accordance with Figure 3 A similar connection method can be used to connect to the inverter. Figure 4 As shown, it should be noted that the power line of the DC positive output terminal of the connected optimizer group in each string passes through the inside of each magnetic ring. In fact, the power line of the DC negative output terminal of the connected optimizer group in the string can also pass through the inside of each magnetic ring, which is not elaborated here.

[0093] 3. The device includes a group string, and the group string includes at least two optimizer groups.

[0094] With the above Figure 5 Similarly, when the device includes a string, and the string includes at least two optimizer groups, a voltage will be generated at both ends of the corresponding capacitor connected to each optimizer group, wherein the power line connecting the DC positive output end of each optimizer group is represented by a solid line, and the power line connecting the DC negative output end of each optimizer group is represented by a dotted line. Then, the power line (i.e., the solid line) connecting the DC positive output end of each optimizer group in the string passes through the inside of the magnetic ring, such as Figure 5 This is the case shown.

[0095] In the case where this type of string includes at least two optimizer groups, the PLC signal can be coupled to the power lines of multiple strings at the same time, but this coupling method has certain current requirements for the magnetic ring, that is, the influence of the sum of the currents of multiple strings must not cause the magnetic ring to saturate.

[0096] It should be noted that in some embodiments of the present application, the power line connecting the DC negative output terminal of each optimizer group in the string may pass through the inside of the magnetic ring, and the above Figure 6Similarly, the power line (i.e., the dotted line) connecting the DC negative output terminal of each optimizer group in the string passes through the inside of the magnetic ring.

[0097] It should also be noted that in some embodiments of the present application, since the string includes at least two optimizer groups, the power line connecting the positive pole of the DC output terminal of the first optimizer group and the power line connecting the negative pole of the DC output terminal of the second optimizer group can also pass through the inside of the magnetic ring, wherein the first optimizer group and the second optimizer group are two different optimizer groups among the above multiple optimizer groups. Figure 7 Similarly, the power line (i.e., solid line) connecting the DC positive output terminal of one optimizer group in the string passes through the inside of the magnetic ring, and the power line (i.e., dotted line) connecting the DC negative output terminals of two optimizer groups passes through the inside of the magnetic ring; in some embodiments of the present application, the power line (i.e., solid line) connecting the DC positive output terminals of the two optimizer groups may pass through the inside of the magnetic ring, and the power line (i.e., dotted line) connecting the DC negative output terminal of one optimizer group may pass through the inside of the magnetic ring, as long as the power lines passing through the magnetic ring include both the power line connecting the DC negative output terminal of the optimizer group and the power line connecting the DC positive output terminal of the optimizer group, and no specific limitation is made here.

[0098] The above-mentioned method of mixing the power lines connecting the DC positive output terminal or the negative output terminal of the optimizer group through the magnetic ring can reduce the requirements for the magnetic ring current. Because the influence of the magnetic ring current mainly comes from the large attenuation of the magnetic ring magnetic permeability caused by the bias generated by the current. For example, assuming that there are 6 optimizer groups in the string that need to be connected to the inverter, the power lines connecting the DC positive output terminals of the 1st, 2nd, and 3rd optimizer groups and the power lines connecting the DC negative output terminals of the 4th, 5th, and 6th optimizer groups can be passed through the magnetic ring together. Since the current on the power line connecting the DC positive output terminal of the 1st, 2nd, and 3rd optimizer groups is opposite to the current on the power line connecting the DC negative output terminal of the 4th, 5th, and 6th optimizer groups, the directions of the magnetic fluxes generated by each are also opposite, and they will cancel each other out when superimposed together, thereby greatly reducing the bias effect on the magnetic ring.

[0099] 4. The device includes at least two strings, each of which includes at least two optimizer groups.

[0100] When the device includes at least two strings, and each string includes at least two optimizer groups (each optimizer group includes at least one optimizer, and each optimizer is connected to a corresponding PV module), each string can be connected according to Figures 5 to 7 A similar connection method is used to connect to the inverter to enable the inverter to control multiple optimizer groups in multiple strings, which will not be described in detail here.

[0101] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A system using power line communication, characterized in that: include: An inverter, at least one optimizer group, wherein one optimizer group includes a plurality of optimizers; The inverter includes at least one capacitor, a magnetic ring, a power line and a signal line; The multiple optimizers are used to connect to multiple photovoltaic modules, and are used to convert the direct current output by each photovoltaic module into adjustable direct current. The multiple optimizers are connected in series with each other and connected to at least one capacitor in the inverter through the power line; The power line connected to any one end of the at least one capacitor passes through the interior of the magnetic ring; The signal line passes through the interior of the magnetic ring and is connected to the interior of the inverter, and the signal line, the power line, the magnetic ring and the at least one capacitor are used to transmit a power line communication PLC signal; The electric power line connected to any one end of the at least one capacitor passing through the interior of the magnetic ring comprises: A power line connected to the DC positive output terminal of the optimizer group passes through the interior of the magnetic ring; or A power line connected to the DC negative output terminal of the optimizer group passes through the inside of the magnetic ring.

2. The system according to claim 1, characterized in that The at least one optimizer group specifically includes a plurality of optimizer groups, wherein: A power line connecting the negative pole of the DC output terminal of each optimizer group in the plurality of optimizer groups passes through the interior of the magnetic ring.

3. The system according to claim 1, characterized in that The at least one optimizer group specifically includes a plurality of optimizer groups, wherein: A power line connecting the positive pole of the DC output terminal of each optimizer group in the plurality of optimizer groups passes through the interior of the magnetic ring.

4. The system according to claim 1, characterized in that The at least one optimizer group specifically includes a first optimizer group and a second optimizer group, wherein: A power line connecting the positive pole of the DC output terminal of the first optimizer group and a power line connecting the negative pole of the DC output terminal of the second optimizer group pass through the inside of the magnetic ring, wherein the first optimizer group and the second optimizer group are two different optimizer groups among the at least one optimizer group.

5. An inverter using power line communication, characterized in that: include: at least one capacitor, magnetic ring, power line and signal line; The at least one capacitor is used to be connected to at least one optimizer group through the power line, and one optimizer group includes a plurality of optimizers; The power line connected to any one end of the at least one capacitor passes through the interior of the magnetic ring; The signal line passes through the interior of the magnetic ring and is connected to the interior of the inverter, and the signal line, the power line, the magnetic ring and the at least one capacitor are used to transmit a power line communication PLC signal; The electric power line connected to any one end of the at least one capacitor passing through the interior of the magnetic ring comprises: A power line connected to the DC positive output terminal of the optimizer group passes through the interior of the magnetic ring; or A power line connected to the DC negative output terminal of the optimizer group passes through the inside of the magnetic ring.

6. The inverter according to claim 5, characterized in that: The power line includes multiple power lines, among which the power line connected to the DC negative output terminal of the first optimizer group in the optimizer group passes through the interior of the magnetic ring, and the power line connected to the DC positive output terminal of the second optimizer group in the optimizer group passes through the interior of the magnetic ring.

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