Power converter and PLC system

Abstract

The present application relates to the technical field of photovoltaics, and provides a power converter and a PLC system. The power converter provided by the present application comprises N change-over switches, one end of each of the N change-over switches is connected to a receiving filter, and the other end of each of the N change-over switches is connected to a corresponding coupler among N couplers. During switch-on of one change-over switch, a PLC chip can control the other change-over switches to be switched off, so as to ensure that the receiving filter and the PLC chip only receive and process a received signal from one coupler each time. Therefore, noise signals transmitted by the other couplers can be effectively prevented from being superposed on the received signal processed by the PLC chip, thereby effectively improving the signal-to-noise ratio of the received signal, and ensuring the reliability of PLC.

Description

Power converter and PLC system

[0001] This application claims priority to Chinese patent application No. 202410052000.X, filed on January 11, 2024, entitled “Power Converter and PLC System,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of photovoltaic technology, and in particular to a power converter and a PLC system. Background Art

[0003] A photovoltaic (PV) power generation system typically consists of components such as photovoltaic panels, power converters (also called inverters), and box-type transformers (box-type transformers). The power converters convert the direct current (DC) output from the PV panels into alternating current (AC). The box-type transformers convert the AC output from the inverter into a higher voltage.

[0004] Photovoltaic power generation systems generally also include a photovoltaic optimizer, which can perform maximum power point tracking (MPPT) on photovoltaic panels to ensure the maximum output power of the photovoltaic panels. Typically, each photovoltaic panel can be connected to a photovoltaic optimizer, and the output ends of multiple photovoltaic optimizers are connected in series to form an optimizer string, which is then connected to a power converter. Among them, the power converter and the photovoltaic optimizers in the optimizer string can communicate through power line communication (PLC) technology to achieve information interaction operations such as business queries and command control. The power converter generally includes a PLC chip, a transmitting circuit, a receiving circuit and multiple couplers. Among them, the transmitting circuit is used to process the transmitting signal output by the PLC chip, and the receiving circuit is used to process the receiving signals from the multiple couplers and send the processed receiving signals to the PLC chip. The multiple couplers are used to connect to the multiple optimizer strings via power lines.

[0005] Since multiple couplers are connected to the PLC chip through the receiving circuit, when the PLC chip receives and processes the received signal transmitted by any coupler, the noise signals transmitted by other couplers will also be superimposed on the received signal, affecting the signal-to-noise ratio of the received signal.

[0006] Summary of the Invention

[0007] The present application provides a power converter and a PLC system, which can solve the technical problem in the related art that the superposition of noise signals from multiple couplers in the PLC system affects the signal-to-noise ratio of the received signal.

[0008] In a first aspect, a power converter is provided, comprising: a PLC chip, a transmitting circuit, a receiving filter, N switches, and N couplers, where N is an integer greater than 1. Each of the N couplers is configured to connect to multiple photovoltaic optimizers connected in series, and each photovoltaic optimizer is configured to connect to a photovoltaic panel. The PLC chip is connected to the transmitting circuit and the receiving filter, respectively. The transmitting circuit is also connected to the N couplers. The receiving filter is also connected to one end of each of the N switches, and the other ends of the N switches are connected to the N couplers in a one-to-one correspondence. The PLC chip is configured to output a transmit signal; the transmitting circuit is configured to process the transmit signal; each of the N couplers is configured to couple the processed transmit signal to a power line and transmit it to the photovoltaic optimizer, and to receive a receive signal transmitted from the photovoltaic optimizer via the power line. The PLC chip is configured to control the remaining switches in the N switches to be closed when one of the N switches is closed. The receiving filter is used to filter the receiving signal and transmit the filtered receiving signal to the PLC chip.

[0009] In the solution provided by this application, since the PLC chip can control the other switches to be off while one switch is closed, it can ensure that the receive filter and PLC chip only receive and process the received signal from one coupler at a time. This effectively prevents noise signals transmitted by other couplers (such as noise signals from the DC / DC converter circuit) from being superimposed on the received signal processed by the PLC chip, thereby effectively improving the signal-to-noise ratio of the received signal.

[0010] Optionally, the PLC chip stores a correspondence between the multiple PV optimizers and the N switches. A transmission signal output by the PLC chip carries an identifier of a target PV optimizer, and the transmission signal is used to instruct the target PV optimizer to report a received signal. The PLC chip is configured to, when receiving a received signal from the target PV optimizer, control the closure of the switch corresponding to the target PV optimizer among the N switches based on the correspondence between the multiple PV optimizers and the N switches.

[0011] The corresponding relationship can be acquired by the PLC chip through communication with the multiple PV optimizers. For example, the PLC chip can control N switches to close sequentially, and when each switch is closed, receive an identifier (e.g., address information) reported by each PV optimizer corresponding to the switch. The PLC chip can then store the corresponding relationship between the identifiers reported by the multiple PV optimizers and the closed switches.

[0012] Optionally, the power converter may further include a controller configured to control the plurality of photovoltaic optimizers. The PLC chip may also be configured to modulate information sent by the controller (e.g., shutdown control instructions, status query instructions, or upgrade instructions) to obtain the transmit signal, and to demodulate the received signal and transmit the demodulated signal to the controller. The received signal may include information (e.g., status information) reported by the photovoltaic optimizer to the controller.

[0013] Optionally, the transmission circuit may include: N power amplifiers. Inputs of the N power amplifiers are each connected to the PLC chip, and outputs of the N power amplifiers are connected in a one-to-one correspondence with the N couplers. Each of the N power amplifiers is configured to amplify the power of the transmission signal output by the PLC chip and transmit the power-amplified transmission signal to a corresponding coupler.

[0014] Since N power amplifiers are provided in the transmitting circuit, it can be ensured that the power of the transmitting signal emitted by each coupler is high, thereby effectively improving the signal-to-noise ratio of the PLC system and ensuring the reliability of the PLC system communication.

[0015] Optionally, the isolation between the output ends of the N power amplifiers is greater than a threshold. That is, the isolation between the output ends of the N power amplifiers can be relatively large, thereby effectively preventing noise on one receiving channel from being fed back to other receiving channels through the power amplifier, thereby affecting the independence of the receiving channels and the signal-to-noise ratio of the received signal.

[0016] In a second aspect, another power converter is provided, comprising: N PLC chips, a transmission circuit, N receive filters, and N couplers, where N is an integer greater than 1. Each of the N couplers is configured to connect to multiple photovoltaic optimizers connected in series, and each photovoltaic optimizer is configured to connect to a photovoltaic panel. The input ends of the N receive filters are connected to the N couplers in a one-to-one correspondence, and the output ends of the N receive filters are connected to the N PLC chips in a one-to-one correspondence. The N PLC chips include a master PLC chip, which is connected to the transmission circuit, which is also connected to the N couplers. The master PLC chip is configured to output a transmit signal; the transmit circuit is configured to process the transmit signal. Each of the N couplers is configured to couple the processed transmit signal to a power line and transmit it to the photovoltaic optimizer, and to receive a receive signal from the photovoltaic optimizer transmitted through the power line. Each of the N receive filters is configured to receive a receive signal transmitted by a corresponding coupler, filter the receive signal, and transmit it to the corresponding PLC chip.

[0017] In the power converter provided by this application, the provision of N receive filters and N PLC chips ensures that the received signal transmitted by each coupler can be independently transmitted and processed. This effectively avoids the superposition of noise signals transmitted by other couplers (e.g., noise signals from the DC / DC converter circuit), thereby improving the signal-to-noise ratio of the received signal.

[0018] Optionally, the power converter may further include a controller, the N PLC chips being connected to the controller. Each of the N PLC chips is configured to demodulate a received signal and transmit the demodulated signal to the controller. The master PLC chip is further configured to modulate information sent by the controller to generate a transmit signal.

[0019] Since the N PLC chips are all connected to the controller and can directly transmit the demodulated received signals to the controller, there is no need for the main PLC chip to aggregate the received signals before transmitting them to the controller, which can effectively simplify the functional design of the main PLC chip.

[0020] Optionally, the power converter may further include: a controller, the master PLC chip being connected to the controller and connected to other slave PLC chips among the N PLC chips except the master PLC chip. The slave PLC chip is configured to demodulate a received signal and transmit the demodulated signal to the master PLC chip. The master PLC chip is further configured to demodulate the received signal and transmit the demodulated signal and the demodulated signal transmitted by the slave PLC chip to the controller, and to modulate information sent by the controller to obtain a transmit signal.

[0021] Since the master PLC chip can aggregate the received signals demodulated by each slave PLC chip and then transmit them to the controller, the controller no longer needs to communicate with other slave PLC chips, which can effectively simplify the functional design of the controller.

[0022] Optionally, the transmission circuit may include N power amplifiers. The input ends of the N power amplifiers are all connected to the main PLC chip, and the output ends of the N power amplifiers are connected to the N couplers in a one-to-one correspondence. Each of the N power amplifiers is configured to amplify the power of the transmission signal output by the main PLC chip and transmit the power-amplified transmission signal to a corresponding coupler.

[0023] Optionally, the isolation between the output ends of the N power amplifiers is greater than a threshold.

[0024] In a third aspect, a PLC system is provided, comprising: a plurality of photovoltaic optimizers, and a power converter as provided in the first or second aspect. The power converter includes N couplers, each of the N couplers being connected to at least two photovoltaic optimizers connected in series among the plurality of photovoltaic optimizers, each photovoltaic optimizer being configured to connect to a photovoltaic panel, where N is an integer greater than 1.

[0025] In summary, the present application provides a power converter and a PLC system. In the solution provided in the present application, the power converter includes N switches, one end of each of the N switches is connected to a receiving filter, and the other end is connected to N couplers in a one-to-one correspondence. The PLC chip can control the other switches to be turned off when one of the switches is closed, so as to ensure that the receiving filter and the PLC chip only receive and process the received signal from one coupler at a time. Thus, it is possible to effectively prevent the noise signals transmitted by other couplers from being superimposed on the received signal processed by the PLC chip, thereby effectively improving the signal-to-noise ratio of the received signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic structural diagram of a PLC system provided in an embodiment of the present application;

[0027] FIG2 is a schematic structural diagram of another PLC system provided in an embodiment of the present application;

[0028] FIG3 is a schematic structural diagram of another PLC system provided in an embodiment of the present application;

[0029] FIG4 is a schematic structural diagram of a power converter provided in an embodiment of the present application;

[0030] FIG5 is a schematic structural diagram of another PLC system provided in an embodiment of the present application;

[0031] FIG6 is a schematic structural diagram of another power converter provided in an embodiment of the present application;

[0032] FIG7 is a schematic structural diagram of another power converter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The power converter and PLC system provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings. First, the key terms involved in the embodiments of the present application are introduced.

[0034] Inverter: Also known as power converter, it is a DC to AC power supply used to convert the direct current of photovoltaic panels into alternating current.

[0035] PV module: Photovoltaic panel.

[0036] PV string: Multiple photovoltaic panels are connected in series to form a PV string, and multiple PV strings are connected in parallel to the inverter as DC input.

[0037] String inverter power station: All photovoltaic modules in the power station are grouped. The direct current generated by each group of photovoltaic modules is converted into alternating current through a string inverter. The alternating current is then aggregated, boosted, and connected to the grid.

[0038] Box transformer: the abbreviation of box-type transformer, which contains low-voltage distribution cabinet and transformer.

[0039] A photovoltaic optimizer is a DC-to-DC power supply that converts the DC power from photovoltaic panels into regulated DC power. A photovoltaic optimizer can be connected to one or more photovoltaic panels.

[0040] Optimizer string: Multiple PV optimizers are connected in series to form an optimizer string, and multiple PV optimizer strings are connected in parallel to the inverter as DC input.

[0041] A photovoltaic disconnector is a switch that cuts off the output of a photovoltaic panel. Typically, each photovoltaic panel is equipped with a photovoltaic disconnector. In dangerous situations, it can quickly disconnect the connection between photovoltaic panels, reducing the voltage of the PV string.

[0042] MPPT: Real-time detection of the power output of the photovoltaic panel (such as voltage and current) to ensure that the photovoltaic panel operates at maximum power.

[0043] Photovoltaic panels are the core components of photovoltaic power generation systems. They are greatly affected by light radiation. When blocked, the power generation will be significantly reduced. In addition, since the voltage of photovoltaic panels is very high after being connected in series, in the event of dangerous situations such as fire, there needs to be a way to reduce the voltage of the photovoltaic panel string to protect personal safety. Therefore, photovoltaic power generation systems are generally also equipped with photovoltaic circuit breakers, which can control the on and off of the output voltage of the photovoltaic panels. Figure 1 is a structural schematic diagram of a photovoltaic power generation system provided by an embodiment of the present application. As shown in Figure 1, each photovoltaic panel 01 can be connected to a photovoltaic circuit breaker 02, and multiple photovoltaic circuit breakers 02 can be connected in series to form a string. When the photovoltaic circuit breaker 02 is closed, the voltage of the string is equal to the series voltage of each photovoltaic panel 01. When the photovoltaic circuit breaker 02 is disconnected, the voltage of the string is basically equal to 0V. In dangerous situations, the photovoltaic circuit breaker 02 can be controlled to disconnect and quickly shut off the connection between the photovoltaic panels 02, thereby reducing the voltage of the string. The power converter 03 and the photovoltaic circuit breaker 02 communicate with each other through the PLC technology, and the power converter 03 is the CCO of the PLC system, and the photovoltaic circuit breaker 02 is the STA of the PLC system.

[0044] As shown in Figure 1, the PV circuit breaker can be replaced with a PV optimizer, which features MPPT functionality and ensures maximum output power for the PV panels 01. In a PV power generation system, the DC output of the PV optimizer or PV circuit breaker 02 is controlled by the power converter 03 to maintain the DC bus voltage within an appropriate safety range. Therefore, the reliability of the PLC communication between the power converter 03 and the PV optimizer or PV circuit breaker 02 is crucial.

[0045] FIG2 is a schematic structural diagram of another photovoltaic power generation system provided in an embodiment of the present application. As shown in FIG1 and FIG2, the power converter 03 may include a PLC host 031, multiple couplers 032, multiple direct current (DC / DC) conversion circuits 033, and a DC / AC circuit 034. The PLC host 031 is used to communicate with the PLC slave in the photovoltaic optimizer or photovoltaic shut-off device 02 to realize the transmission and reception of PLC signals; the multiple couplers 032 are used to connect one-to-one with multiple strings (optimizer strings or shut-off strings) through power lines; the multiple DC / DC conversion circuits 033 can be used for voltage stabilization and to realize MPPT; the DC / AC circuit 034 is used to convert AC power into DC power and output it to the power grid. The PLC host 031 may include a PLC chip, a transmitting circuit, and a receiving circuit, and the PLC slave may also include a PLC chip, a transmitting circuit, and a receiving circuit. The PLC chip is used to implement signal modulation and demodulation, the transmitting circuit is used to process the transmitting signal (eg, amplify the power of the transmitting signal), and the receiving circuit is used to process the receiving signal (eg, filter the receiving signal).

[0046] Referring to Figure 2, the PLC host 031 is connected to the multiple couplers 032 (such as magnetic rings, inductors or capacitors). The sending signal emitted by the PLC host 031 can be coupled to the power line through the multiple couplers 032, and then transmitted to the photovoltaic optimizers or photovoltaic disconnectors 02 in the multiple strings.

[0047] As shown in Figure 2, a power converter 03 is connected to two strings, and a magnetic ring is used as coupler 032. When a PLC host 031 transmits a signal, the signal is coupled to power lines PV1- and PV2- via magnetic ring 032, and then transmitted to the two strings via the power lines. In other words, the transmit signal is split between the two strings. When receiving a signal, the signals from the two strings are coupled to the PLC host 031 via magnetic ring 032.

[0048] Referring to FIG2 , it can be seen that for the transmission path of PLC signals (including transmit and receive signals), two magnetic rings are equivalent to being connected in parallel. If the power converter 03 is connected to multiple strings and uses multiple magnetic rings, inductors, or capacitors for coupling, this is equivalent to connecting multiple couplers 032 in parallel for the PLC signal transmission path. Connecting multiple couplers 032 in parallel can increase PLC signal loss. For example, if two magnetic rings are connected in parallel, the PLC signal is theoretically attenuated by half, meaning the strength of the PLC signal transmitted to each string is theoretically only half the strength of the PLC signal emitted by the PLC host 031. Correspondingly, if N (N is an integer greater than 1) magnetic rings are connected in parallel, the strength of the PLC signal transmitted to each string is theoretically only 1 / N of the original strength. Furthermore, when multiple couplers 032 are connected in parallel, as shown in FIG2 , when receiving signals, the noise from multiple DC / DC conversion circuits 033 can be superimposed through the couplers 032 and enter the receiving channel of the PLC host 031, severely affecting the signal-to-noise ratio of the received signal.

[0049] The embodiment of the present application provides a power converter, which can effectively reduce the superposition of noise signals in the receiving channel, thereby effectively improving the signal-to-noise ratio of the PLC system and ensuring the reliability of PLC communication. As shown in Figures 3 and 4, the power converter provided in the embodiment of the present application includes: a PLC chip 10, a transmitting circuit 20, a receiving circuit 30 and N couplers 40. Wherein, the receiving circuit 30 includes a receiving filter 301 and N switching switches 302. Each coupler 40 in the N couplers 40 is used to connect multiple photovoltaic optimizers in series, and each photovoltaic optimizer is used to connect photovoltaic panels. The structures of the N couplers 40 can be the same. For example, each coupler 40 can include coupling devices such as magnetic rings, inductors and / or capacitors.

[0050] Continuing with reference to Figures 3 and 4, the PLC chip 10 is connected to the transmitting circuit 20 and the receiving filter 301, respectively. The transmitting circuit 20 is also connected to the N couplers 40. The receiving filter 301 is also connected to one end of each of the N switches 302, and the other ends of the N switches 302 are connected to the N couplers 40 in a one-to-one correspondence.

[0051] The PLC chip 10 is configured to output a transmission signal. The transmission circuit 20 is configured to process the transmission signal, for example, to amplify the power of the transmission signal. Each of the N couplers 40 is configured to couple the processed transmission signal to the power line for transmission to the photovoltaic optimizer, and to receive a reception signal from the photovoltaic optimizer via the power line. The transmission signal may include shutdown control instructions, status query instructions, and / or upgrade instructions issued by the power converter. The reception signal may carry status information reported by the photovoltaic optimizer.

[0052] The PLC chip 10 is used to control the other switches in the N switches 302 to be turned off when one switch 302 in the N switches 302 is turned on.

[0053] The receiving filter 301 is used to filter the received signal and transmit the filtered received signal to the PLC chip 10 .

[0054] In the embodiment of the present application, the PLC chip 10 can control only one switch 302 to be closed at a time, so as to ensure that the receiving filter 301 and the PLC chip 10 only receive and process the reception signal from one coupler 40 at a time. In this way, it is possible to effectively prevent the noise signals transmitted by other couplers 40 (such as the noise signals from the DC / DC conversion circuit) from being superimposed on the reception signal processed by the PLC chip 10, thereby effectively improving the signal-to-noise ratio of the reception signal and ensuring the reliability of PLC communication.

[0055] Furthermore, since the receiving filter 301 and the PLC chip 10 can receive and process the receiving signals transmitted by different couplers 40 in a time-division manner, thereby isolating the receiving channels, only one PLC chip 10 is required in the power converter provided in the embodiment of the present application. This effectively simplifies the circuit design of the power converter, thereby reducing the hardware cost and structural complexity of the power converter.

[0056] Optionally, referring to FIG4 , the PLC chip 10 can output control signals to N switches 302 to implement on / off control of the N switches. For example, the PLC chip 10 can output a control signal 1 to the first switch 302 and a control signal N to the Nth switch 302. If the control signal output by the PLC chip 10 to a particular switch 302 is at a first level, the switch 302 can be closed; if the control signal is at a second level, the switch 302 can be closed. The first level can be either a high level or a low level relative to the second level, and this is not limited in this embodiment of the present application.

[0057] Optionally, each of the N switches 302 may include a transistor or a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0058] Optionally, the PLC chip 10 may store a correspondence between multiple PV optimizers and N switches 302. Furthermore, the transmission signal output by the PLC chip 10 may carry an identifier of a target PV optimizer, and the transmission signal may be used to instruct the target PV optimizer to report a received signal. The target PV optimizer may be the PV optimizer that the controller 50 needs to control or obtain information from. The identifier of the target PV optimizer may be the address information of the target PV optimizer.

[0059] Accordingly, the PLC chip 10 can be used to control the closing of the switching switch 302 corresponding to the target photovoltaic optimizer among the N switching switches based on the correspondence between the multiple photovoltaic optimizers and the N switching switches 302 during the process of receiving the receiving signal from the target photovoltaic optimizer.

[0060] It is understood that the controller 50 in the power converter and the photovoltaic optimizer can communicate based on a master-slave protocol, that is, the controller 50 can first send a transmission signal carrying the identification (e.g., address information) of the target photovoltaic optimizer to each photovoltaic optimizer connected to the power converter. After the transmission circuit 20 sends the transmission signal to each photovoltaic optimizer through N couplers 40, each photovoltaic optimizer can parse the identification in the transmission signal and match the resolved identification with its own identification. If the match is successful, the photovoltaic optimizer (i.e., the target photovoltaic device) can report a received signal to the controller 50 in the power converter, such as a received signal carrying status information.

[0061] In an embodiment of the present application, the PLC chip 10 can determine the identifier of the target photovoltaic optimizer in the process of modulating the information sent by the controller 50 to generate a transmission signal. In addition, the PLC chip 10 can determine the switch 302 corresponding to the target photovoltaic optimizer based on the identifier of the target photovoltaic optimizer and the correspondence between the identifiers of multiple photovoltaic optimizers pre-stored in the PLC chip 10 and the N switches 302. After determining that the transmission signal has been sent, the PLC chip 10 can control the switch 302 corresponding to the target photovoltaic optimizer to close and control the other switches 302 to remain in an open state. At this time, the closed switch 302 can transmit the received signal from the target photovoltaic optimizer to the receiving filter 301, so that the receiving filter 301 can filter and transmit it to the PLC chip 10.

[0062] It is also understood that the controller 50 can instruct each PV optimizer to report its status information through polling. For example, the PLC chip 10 can sequentially send a transmission signal carrying the identifiers of different PV optimizers, and each PV optimizer can then sequentially report a received signal carrying its status information based on the identifier in the transmission signal.

[0063] For example, referring to FIG4 , assuming that each coupler 40 is connected to two photovoltaic optimizers in series, the PLC chip 10 can first output a transmission signal 1, which carries the identifier of the photovoltaic optimizer 1 to which the first coupler 40 is connected. Subsequently, the PLC chip 10 can control the first switch 302 connected to the first coupler 40 to close and control all other switches 302 to close in order to receive the reception signal reported by the photovoltaic optimizer 1. Furthermore, the PLC chip 10 can output a transmission signal 2, which carries the identifier of the photovoltaic optimizer 2 to which the first coupler 40 is connected. Subsequently, the PLC chip 10 can receive the reception signal reported by the photovoltaic optimizer 2 through the closed first switch 302.

[0064] After obtaining the received signals reported by the two photovoltaic optimizers connected to the first coupler 40, the PLC chip 10 can output a transmission signal 3, which carries the identifier of the photovoltaic optimizer 3 connected to the second coupler 40. Subsequently, the PLC chip 10 can control the second switch 302 connected to the second coupler 40 to close and control all other switches 302 to close in order to receive the received signals reported by the photovoltaic optimizer 3. Furthermore, the PLC chip 10 can output a transmission signal 4, which carries the identifier of the photovoltaic optimizer 4 connected to the second coupler 40. Subsequently, the PLC chip 10 can receive the received signals reported by the photovoltaic optimizer 4 through the closed second switch 302. Similarly, the power converter can sequentially obtain the received signals from each photovoltaic optimizer connected to N couplers 40 by sending transmission signals carrying different identifiers.

[0065] Optionally, the correspondence between the identifiers of the multiple PV optimizers and the N switches 302 stored in the PLC chip 10 can be manually configured by an operator. Alternatively, the PLC chip 10 can first control the N switches 302 to close sequentially, and as each switch 302 closes, obtain the identifier (e.g., address information) reported by each PV optimizer connected to that switch 302. The PLC chip 10 can then generate and store the correspondence between the identifier reported by each PV optimizer and the closed switch 302.

[0066] Optionally, as shown in Figures 3 and 4, the transmitting circuit 20 in the power converter may include N power amplifiers 201, the input ends of the N power amplifiers 201 are connected to the PLC chip 10, and the output ends of the N power amplifiers 201 are connected to N couplers 40 in a one-to-one correspondence. The N power amplifiers 201 are used to amplify the power of the transmit signal output by the PLC chip 10 and transmit the power-amplified transmit signal to the corresponding coupler 40. The power amplifier 201 can also be called a linear driver, or simply a line driver.

[0067] It is understood that the N power amplifiers 201 in the transmission circuit 20 can simultaneously amplify the power of the same transmission signal output by the PLC chip 10. Therefore, the transmission signals output by the N power amplifiers 201 are identical. Accordingly, the transmission signals transmitted by the N couplers 40 to the N PV strings are identical.

[0068] In the power converter provided in this embodiment, the transmitting circuit 20 includes N power amplifiers 201 connected in a one-to-one correspondence with the N couplers 40. This ensures that the power of the signal transmitted by each coupler 40 to the connected photovoltaic optimizer is high. This effectively improves the signal-to-noise ratio of the PLC system and ensures the reliability of PLC system communication.

[0069] Optionally, the isolation between the output ends of the N power amplifiers 201 can be greater than a threshold, that is, the isolation between the output ends can be relatively large. For example, the threshold can be 20 decibels (dB) to 30 dB. Since the input ends of the N power amplifiers 201 are directly connected, by setting the isolation between the output ends of each power amplifier 201 relatively large, it is possible to prevent noise from one receiving channel from being fed back to other receiving channels through the power amplifier 201, thereby affecting the independence of the receiving channels and the signal-to-noise ratio of the received signal.

[0070] For example, when the PLC chip 10 controls the first switch 302 to close in order to receive the received signal transmitted by the first coupler 40, noise signals on other receiving channels may be fed back to the receiving channel where the first switch 302 is located through the power amplifier 201, thereby affecting the signal-to-noise ratio of the received signal transmitted by the first switch 302. In the embodiment of the present application, since the output ends of the power amplifiers 201 are relatively isolated from each other, effective isolation of the noise signal can be achieved, ensuring that each receiving channel is not superimposed on the noise of other receiving channels, thereby effectively improving the signal-to-noise ratio of the received signal.

[0071] Optionally, as shown in FIG3 , the power converter may further include: at least one DC / DC conversion circuit 60, and a DC / AC conversion circuit 70. The at least one DC / DC conversion circuit 60 is connected to the N couplers 40 and is used to perform voltage conversion on the DC power transmitted by the N couplers 40. The DC / AC conversion circuit 70 is connected to the at least one DC / DC conversion circuit 60 and is used to convert the DC power output by the at least one DC / DC conversion circuit 60 into AC power for transmission to the power grid.

[0072] For example, the power converter may include N DC / DC conversion circuits 60 , and the N DC / DC conversion circuits 60 may be connected to N couplers 40 in a one-to-one correspondence.

[0073] In summary, an embodiment of the present application provides a power converter, which includes N switching switches, one end of which is connected to a receiving filter, and the other end is connected to N couplers in a one-to-one correspondence. The PLC chip can control the other switching switches to be turned off when one of the switching switches is closed, so as to ensure that the receiving filter and the PLC chip only receive and process the received signal from one coupler at a time. Thus, it is possible to effectively prevent the noise signals transmitted by other couplers from being superimposed on the received signal processed by the PLC chip, thereby effectively improving the signal-to-noise ratio of the received signal.

[0074] The present application embodiment also provides another power converter, which can also effectively reduce the superposition of noise signals in the receiving channel, thereby effectively improving the signal-to-noise ratio of the PLC system and ensuring the reliability of PLC communication. As shown in Figures 5, 6 and 7, the power converter provided by the present application embodiment includes: N PLC chips 10, a transmitting circuit 20, a receiving circuit 30 and N couplers 40. Wherein, the receiving circuit 30 includes N receiving filters 301, and N is an integer greater than 1. Each coupler 40 in the N couplers 40 is used to connect multiple photovoltaic optimizers in series, and each photovoltaic optimizer is used to connect photovoltaic panels. The structures of the N couplers 40 can be the same, for example, each coupler 40 can include coupling devices such as magnetic rings, inductors or capacitors.

[0075] 5 , 6 , and 7 , the input ends of the N receive filters 301 are connected in a one-to-one correspondence with the N couplers 40, and the output ends of the N receive filters 301 are connected in a one-to-one correspondence with the N PLC chips 10. The N PLC chips 10 include a master PLC chip 10, which is connected to the transmitting circuit 20, which is further connected to the N couplers 40.

[0076] The main PLC chip 10 is configured to output a transmission signal. The transmission circuit 20 is configured to process the transmission signal, for example, to amplify the power of the transmission signal. Each of the N couplers 40 is configured to couple the processed transmission signal to the power line for transmission to the photovoltaic optimizer, and to receive a reception signal from the photovoltaic optimizer via the power line.

[0077] Each of the N receiving filters 301 is configured to receive a receiving signal transmitted by a corresponding coupler 40, filter the receiving signal, and transmit the signal to a corresponding PLC chip 10. Each PLC chip 10 can then demodulate the received signal.

[0078] The power converter provided in the embodiment of the present application can ensure that the received signal transmitted by each coupler 40 can be independently transmitted and processed by providing N independent receiving filters 301 and N independent PLC chips 10. That is, each PLC chip 10 and the receiving filter 301 connected thereto will only receive the signal transmitted by one coupler 40, thereby effectively avoiding the noise signal transmitted by other couplers 40 (such as the noise signal from the DC / DC conversion circuit) from being superimposed on the received signal processed by the PLC chip 10. Thus, the signal-to-noise ratio of the received signal can be effectively improved, ensuring the reliability of PLC communication.

[0079] Optionally, with continued reference to Figures 5, 6, and 7, the power converter may further include a controller 50 configured to control each photovoltaic optimizer connected to the power converter. The master PLC chip 10 may be configured to modulate information transmitted by the controller 50 to be sent to the photovoltaic optimizer to generate a transmission signal. Furthermore, each of the N PLC chips 10 may be configured to demodulate a received signal, allowing the controller 50 to process the demodulated signal.

[0080] Based on the above analysis, it can be seen that the master PLC chip 10 among the N PLC chips 10 can output a transmit signal and can receive and process a receive signal transmitted by the receive filter 301 to which it is connected. Among the N PLC chips 10, the slave PLC chips 10 other than the master PLC chip 10 can receive and process the receive signal transmitted by the receive filter 301 to which it is connected, without having to process the transmit signal.

[0081] As a first possible example, as shown in FIG7 , the N PLC chips 10 can all be connected to the controller 50, and each of the N PLC chips 10 can directly transmit the demodulated received signal to the controller 50. For example, each PLC chip 10 can transmit the demodulated received signal to the controller 50 via a communication bus such as a CAN bus, an IIC bus, an SPI bus, or an RS485 bus.

[0082] As a second possible example, as shown in Figures 5 and 6, among the N PLC chips 10 included in the PLC chip 10, only the master PLC chip 10 is connected to the controller 50, and the other slave PLC chips 10 are all connected to the master PLC chip 10. For example, the master PLC chip 10 is connected to the controller 50 via a communication bus, and each slave PLC chip 10 is connected to the master PLC chip 10 via the communication bus.

[0083] In the second example, among the N PLC chips 10, each slave PLC chip 10 can be used to transmit the demodulated received signal to the master PLC chip 10. The master PLC chip 10 can be used to transmit its demodulated received signal and the demodulated received signals transmitted by other slave PLC chips 10 to the controller 50.

[0084] Based on the above two examples, it can be seen that the N PLC chips 10 included in the power converter can directly transmit the demodulated received signals to the controller 50, or the master PLC chip 10 can aggregate the signals of each slave PLC chip 10 and then report them to the controller 50. For the first example above, since each slave PLC chip 10 can communicate directly with the controller 50, there is no need for the master PLC chip 10 to aggregate the signals and then forward them, which can effectively simplify the circuit design of the master PLC chip 10. For the second example above, since the master PLC chip 10 can aggregate the signals and then forward them to the controller 50, the controller 50 no longer needs to communicate with each slave PLC chip 10 separately, which can effectively simplify the circuit design of the controller.

[0085] Optionally, as shown in Figures 5 to 7, the transmission circuit 20 in the power converter may include N power amplifiers 201. The input ends of the N power amplifiers 201 are all connected to the main PLC chip 10, and the output ends of the N power amplifiers 201 are connected one-to-one with N couplers 40. The N power amplifiers 201 are used to amplify the power of the transmission signal output by the main PLC chip 10 and transmit the power-amplified transmission signal to the corresponding coupler 40.

[0086] It is understood that the N power amplifiers 201 in the transmission circuit 20 can simultaneously amplify the power of the same transmission signal output by the main PLC chip 10. Therefore, the transmission signals output by the N power amplifiers 201 are identical. Accordingly, the transmission signals transmitted by the N couplers 40 to the N PV strings are identical.

[0087] In the power converter provided in this embodiment, the transmitting circuit 20 includes N power amplifiers 201 connected in a one-to-one correspondence with the N couplers 40. This ensures that the power of the signal transmitted by each coupler 40 to the connected photovoltaic optimizer is high. This effectively improves the signal-to-noise ratio of the PLC system and ensures the reliability of PLC system communication.

[0088] Optionally, the isolation between the output ends of the N power amplifiers 201 can be greater than a threshold, that is, the isolation between the output ends can be relatively large. For example, the threshold can be 20 dB to 30 dB. Since the input ends of the N power amplifiers 201 are directly connected, by setting the isolation between the output ends of each power amplifier 201 relatively large, it is possible to prevent noise from one receiving channel from being fed back to other receiving channels through the power amplifier 201, thereby affecting the independence of the receiving channels and the signal-to-noise ratio of the received signal.

[0089] For example, when the PLC chip 10 controls the first switch 302 to close in order to receive the received signal transmitted by the first coupler 40, noise signals on other receiving channels may be fed back to the receiving channel where the first switch 302 is located through the power amplifier 201, thereby affecting the signal-to-noise ratio of the received signal transmitted by the first switch 302. In the embodiment of the present application, since the output ends of the power amplifiers 201 are relatively isolated from each other, effective isolation of the noise signal can be achieved, ensuring that each receiving channel is not superimposed on the noise of other receiving channels, thereby effectively improving the signal-to-noise ratio of the received signal.

[0090] Optionally, as shown in FIG5 , the power converter may further include: at least one DC / DC conversion circuit 60, and a DC / AC conversion circuit 70. The at least one DC / DC conversion circuit 60 is connected to the N couplers 40 and is used to perform voltage conversion on the DC power transmitted by the N couplers 40. The DC / AC conversion circuit 70 is connected to the at least one DC / DC conversion circuit 60 and is used to convert the DC power output by the at least one DC / DC conversion circuit 60 into AC power for transmission to the power grid.

[0091] For example, the power converter may include N DC / DC conversion circuits 60 , and the N DC / DC conversion circuits 60 may be connected to N couplers 40 in a one-to-one correspondence.

[0092] In summary, an embodiment of the present application provides a power converter, which includes N PLC chips and N receiving filters connected to the N PLC chips in a one-to-one correspondence, and the N receiving filters are also connected to N couplers in a one-to-one correspondence. Based on this structural design, it can be ensured that each PLC chip and the receiving filter connected thereto will only receive a signal transmitted by a coupler, thereby effectively avoiding the noise signal transmitted by other couplers (such as a noise signal from a DC / DC conversion circuit) being superimposed on the received signal processed by the PLC chip. Thus, the signal-to-noise ratio of the PLC system can be effectively improved, ensuring the reliability of the PLC system communication.

[0093] An embodiment of the present application further provides a PLC system, as shown in FIG3 and FIG5 , the PLC system includes: a plurality of photovoltaic optimizers 02 , and a power converter 03 as provided in the above example.

[0094] 3 and 5 , the power converter 03 includes N couplers 40 , each of the N couplers 40 being connected to at least two photovoltaic optimizers 02 connected in series among the plurality of photovoltaic optimizers 02 , and each photovoltaic optimizer 02 being configured to connect to a photovoltaic panel 01 , where N is an integer greater than 1.

[0095] It is understood that the PLC system provided in the embodiments of this application can be applied to photovoltaic power station systems, such as string inverter power stations. Furthermore, the photovoltaic power station system can include household power stations and industrial and commercial power stations. Furthermore, the solutions provided in the embodiments of this application can also be applied to other technical fields, such as PLC communication for multi-machine parallel communication power supplies or PLC communication for energy storage systems.

[0096] The above embodiments are all explained using the example of the power converter 03 connected to the photovoltaic optimizer 02. It can also be understood that the power converter 03 provided in the embodiment of the present application can also be connected to multiple photovoltaic circuit breakers connected in series through the coupler 40, and perform PLC communication with the photovoltaic circuit breaker based on the solution provided in the above embodiment.

[0097] In the embodiments of the present application, the terms "first", "second" and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "at least one" means one or more, and "a plurality" means two or more.

[0098] In this application, the term "and / or" simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0099] The above are merely optional embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A power converter, characterized in that, The power converter includes: a power line communication (PLC) chip, a transmitting circuit, a receiving filter, N switching switches, and N couplers, where N is an integer greater than 1; each of the N couplers is used to connect a plurality of photovoltaic optimizers connected in series, and each photovoltaic optimizer is used to connect to a photovoltaic panel; The PLC chip is respectively connected to the transmitting circuit and the receiving filter, the transmitting circuit is further connected to the N couplers, one end of each of the N switching switches is connected to the receiving filter, and the other ends of the N switching switches are connected to the N couplers in one-to-one correspondence; The PLC chip is configured to: output a transmission signal; The transmitting circuit is used to process the transmission signal; Each of the N couplers is used to couple the processed transmission signal to the power line and transmit it to the photovoltaic optimizer, and is used to receive the received signal from the photovoltaic optimizer transmitted by the power line; The PLC chip is configured to: during the closing process of one of the N switching switches, control all other switching switches among the N switching switches to be turned off; The receiving filter is used to: filter the received signal and transmit the filtered received signal to the PLC chip.

2. The power converter according to claim 1, wherein The correspondence between the plurality of photovoltaic optimizers and the N switching switches is stored in the PLC chip; The transmission signal output by the PLC chip carries the identifier of the target photovoltaic optimizer, and the transmission signal is used to instruct the target photovoltaic optimizer to report the received signal; The PLC chip is configured to, during the process of receiving the received signal from the target photovoltaic optimizer, based on the correspondence between the plurality of photovoltaic optimizers and the N switching switches, control the switching switch corresponding to the target photovoltaic optimizer among the N switching switches to close.

3. The power converter according to claim 1 or 2, characterized in that, The power converter further includes: a controller; The PLC chip is further used to modulate the information sent by the controller to obtain the transmission signal, and is used to demodulate the received received signal and transmit the demodulated received signal to the controller.

4. The power converter according to any one of claims 1 to 3, characterized in that, The transmitting circuit includes: N power amplifiers; The input ends of the N power amplifiers are all connected to the PLC chip, the output ends of the N power amplifiers are connected to the N couplers in one-to-one correspondence, and each of the N power amplifiers is used to amplify the power of the transmission signal output by the PLC chip and transmit the transmission signal with amplified power to a corresponding coupler.

5. The power converter according to claim 4, characterized in that The isolation degree between the output ends of the N power amplifiers is greater than a threshold.

6. A power converter, characterized in that, The power converter includes: N PLC chips, a transmitting circuit, N receiving filters, and N couplers, where N is an integer greater than 1; each of the N couplers is used to connect a plurality of photovoltaic optimizers connected in series, and each photovoltaic optimizer is used to connect to a photovoltaic panel; The input ends of the N receiving filters are respectively connected to the N couplers one by one, the output ends of the N receiving filters are respectively connected to the N PLC chips one by one, one of the N PLC chips is a main PLC chip, the main PLC chip is connected to the sending circuit, and the sending circuit is also connected to the N couplers; The main PLC chip is configured to: output a sending signal; The sending circuit is configured to process the sending signal; Each of the N couplers is configured to: couple the processed sending signal to the power line and transmit it to the PV optimizer, and receive the received signal from the PV optimizer transmitted by the power line; Each of the N receiving filters is configured to: receive the received signal transmitted by a corresponding coupler, and filter the received signal and then transmit it to a corresponding PLC chip.

7. The power converter according to claim 6, characterized in that, The power converter further includes: a controller, and the N PLC chips are all connected to the controller; Each of the N PLC chips is configured to demodulate the received received signal and transmit the demodulated received signal to the controller; The main PLC chip is further configured to modulate the information sent by the controller to obtain the sending signal.

8. The power converter according to claim 6, characterized in that, The power converter further includes: a controller, the main PLC chip is connected to the controller and is also connected to other slave PLC chips among the N PLC chips except the main PLC chip; The slave PLC chip is configured to demodulate the received received signal and transmit the demodulated received signal to the main PLC chip; The main PLC chip is further configured to demodulate the received received signal, transmit both the demodulated received signal and the demodulated received signal transmitted by the slave PLC chip to the controller, and modulate the information sent by the controller to obtain the sending signal.

9. The power converter according to any one of claims 6 to 8, characterized in that, The sending circuit includes N power amplifiers; The input ends of the N power amplifiers are all connected to the main PLC chip, the output ends of the N power amplifiers are respectively connected to the N couplers one by one, and each of the N power amplifiers is configured to amplify the power of the sending signal output by the main PLC chip and transmit the sending signal with amplified power to a corresponding coupler.

10. The power converter according to claim 9, characterized in that, The isolation degree between the output ends of the N power amplifiers is greater than a threshold.

11. A PLC system, characterized in that, The PLC system includes: a plurality of PV optimizers, and a power converter as described in any one of claims 1 to 10; The power converter includes N couplers, each of the N couplers is connected to at least two series-connected PV optimizers among the plurality of PV optimizers, and each PV optimizer is used to connect a PV panel, and N is an integer greater than 1.

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