Maximum power point tracking device for assembly in photovoltaic string

Abstract

The utility model provides a photovoltaic string assembly maximum power point tracking device comprising a bus current measuring circuit (11), a voltage measuring module (22), an MPPT module (21), a second communication module (23), and at least one of a third communication module (61), a first communication module (12) and a main communication module. The system is characterized in that the bus current measuring circuit (11) is used for measuring the current of a direct current bus at a first position of a photovoltaic string direct current bus; the voltage measurement module (22) is used for carrying out photovoltaic module voltage measurement at a power output port position of a photovoltaic module contained in the photovoltaic string; and the second communication module (23) is located at a power output port position of the photovoltaic module and is used for receiving a bus current value obtained by carrying out direct current bus current measurement at a first position of the photovoltaic string direct current bus and transmitting the bus current value to the MPPT module (21). And MPPT current measurement power consumption and cost are reduced.

Description

Technical Field

[0001] The utility model relates to the field of photovoltaic power generation, in particular to a maximum power point tracking device for components in a photovoltaic string. Background Art

[0002] When the performance of each component connected in series is consistent and the illumination is consistent, the maximum power point tracking of the photovoltaic string can be achieved by using a string-level optimizer. When there are obvious differences in component performance or illumination in the series-connected photovoltaic string, a component-level optimizer is required to track the maximum power point of the photovoltaic components with degraded performance.

[0003] The module-level optimizer adjusts the output power of the photovoltaic module so that it works at the maximum power point of the photovoltaic module in real time. The maximum power point tracking (MPPT) of the photovoltaic module is the core function of the optimizer. MPPT includes two links: searching and tracking the maximum power point. In the search and tracking of the maximum power point, in order to determine the maximum power value output by the photovoltaic module, the existing methods include a dual-sensor MPPT algorithm that uses the current and voltage of the photovoltaic module for power calculation and a single-sensor MPPT algorithm that uses voltage for power judgment.

[0004] Examples of optimizers that use dual sensors to implement MPPT include: Patent application number CN202311141186.8, invention name “A photovoltaic power optimizer for shadow shading”, and patent application number 202310170681.5, invention name “A self-diagnostic optimizer system, self-diagnostic optimization method”. The methods given in these two patent applications both include connecting a current measurement unit in series in the power output circuit of the photovoltaic module to measure the output current value of the photovoltaic module.

[0005] Examples of optimizers that use a single sensor to implement MPPT include: Patent application number CN109546961B, invention name "A single sensor photovoltaic module optimizer and its control method". The input end of the DC-DC converter is connected to the photovoltaic cell, and the output end is connected to the digital pulse width modulator through the differential sampling conditioning circuit, the A / D module and the MPPT algorithm module in sequence. The output end of the digital pulse width modulator is connected to the switch tube of the DC-DC converter through the drive circuit. The control method includes the steps of initializing the single sensor photovoltaic module optimizer, detecting the output voltage of the DC-DC converter, determining the duty cycle change speed, adjusting the current duty cycle and outputting it to the switch tube of the DC-DC converter until the output of the DC-DC converter reaches the maximum power point. The beneficial effect of the utility model is that MPPT control is achieved by only one voltage sensor. This patent application does not use current measurement values ​​for MPPT tracking.

[0006] From the configuration of the optimizer in the photovoltaic string, it can be divided into distributed configuration, centralized configuration and hybrid configuration. Among them, the example of hybrid configuration is: the patent application with application number CN201880012229.3 and invention name "Distributed / Centralized Optimizer Architecture". The optimizer hybrid configuration given in this application includes: multiple photovoltaic modules, each of which has a DC voltage output; multiple distributed power optimizers, each of which has an input and a DC voltage output connected to the DC voltage output of one of the photovoltaic modules; a centralized optimizer, having a DC voltage output and an input connected to the combined DC voltage output of a group of distributed power optimizers. The information transmission between the centrally configured optimizer and the distributedly configured optimizer includes: reporting the operating status of the multiple distributed power optimizers to the centralized optimizer, wherein the operating status includes one or more of the following: a normal state of the distributed power optimizer, an output voltage limiting state in which the distributed power optimizer limits its output voltage, or an output power limiting state in which the distributed power optimizer limits its output power; reporting an abnormal condition to one or more of the multiple distributed power optimizers, wherein the abnormal condition includes one or more of the following: an undervoltage condition of the input of the centralized optimizer or an overvoltage condition of the input of the centralized optimizer.

[0007] From the optimizer's use of the communication link, there are two modes: with communication and without communication.

[0008] Examples of non-communication include: Patent application with application number CN202110658226.0 and invention name "Non-communication working mode selection method for series photovoltaic power optimizer". After startup, the power optimizer detects its own output voltage, turns on the power optimizer when it is lower than the lower limit of the hysteresis threshold, and turns off the power optimizer when it is higher than the upper limit of the hysteresis threshold; after the lighting conditions meet the threshold of the number of power optimizer startups, the entire series photovoltaic power optimizer system completes startup and transmits power to the next stage; after the system startup is completed, when the output voltage is higher than the shutdown threshold, the power optimizer enters the standby state and waits for the lighting conditions to change; in the standby state, when the output voltage is detected to be lower than the restart threshold, the power optimizer restarts. In the utility model, each power optimizer selects the working mode according to the electrical parameters of its own port. Each power optimizer does not require a communication module, and can achieve safe startup, operation, shutdown and restart, reducing hardware and installation costs.

[0009] Examples of using communication include: patent application number CN201610128952.0, invention name “A method for data transmission between optimizers in a solar base station”; patent application number CN201620173531.5, invention name “A networked voltage sampling circuit in a solar optimizer”.

[0010] The patent application with application number CN201610128952.0 includes: a single base station communication unit and a whole system communication network. The single base station communication unit is fixed in a solar power generation optimization unit and is used to transmit the input current and output voltage of the solar power generation optimization unit. The single base station communication unit includes: an MCU microcontroller (1), an M / P power supply unit (2), a PLC power line carrier communication unit (3), and an RS_232 serial communication unit (4); the M / P power supply unit (2) is connected to the power supply end of the MCU microcontroller (1) and the PLC power line carrier communication unit (3), and the M / P power supply unit (2) supplies power to the whole system; the R / T interface of the MCU microcontroller (1) is connected to the R1 / T1 interface of the RS_232 serial communication unit (4), and the R2 / T2 interface of the RS_232 serial communication unit (4) is connected to the R1 / T2 interface of the RS_232 serial communication unit (4). The device is connected to an R / T interface of a PLC power line carrier communication unit (3); when a communication data packet is sent by an MCU microcontroller (1), the MCU microcontroller sends the data packet to the R / T interface end, performs data conversion through an RS_232 serial communication unit (4) and sends the data packet to the PLC power line carrier communication unit (3), and then the PLC power line carrier communication unit sends the data packet to a data network; when the MCU microcontroller (1) needs to receive data, the data packet in the communication network is first transmitted to the PLC power line carrier communication unit (3), and then the PLC power line carrier communication unit sends the data packet to the RS_232 serial communication unit (4), and the RS_232 serial communication unit processes the data packet, and finally the MCU microcontroller (1) completes data reception, thereby realizing data communication between solar power generation optimization units. The current and voltage information of the solar power generation optimization unit is transmitted through the power line carrier The signal unit is uploaded to the whole system communication network Each solar power generation optimization unit and the central processor decide whether to adjust the bidirectional DC-AC converter working mode according to the current and voltage information of the single solar power generation optimization unit. The current and voltage information of the solar power optimization unit is uploaded to the whole system communication through the power line carrier communication unit In the network " operation still requires " Solar Power Generation Optimization Unit "The current is measured.

[0011] The patent application with application number CN201620173531.5 comprises: a single voltage sampling circuit, a horizontal voltage sampling circuit series branch, and a vertical branch parallel topology circuit network; in the single voltage sampling circuit, a voltage detection circuit (2) is provided on the positive output circuit of the photovoltaic module (1), the voltage detection circuit (2) is a resistor Ri connected in series on the positive output circuit of the photovoltaic module (1), the two ends of the resistor Ri are electrically connected to the two input ends of the measuring amplifier T5, and the output end of the measuring amplifier T5 is electrically connected to another A / D input end of the optimization processing circuit (3); by detecting the voltage of the resistor Ri, the output current of the photovoltaic module (1) is obtained according to Ohm's law; the horizontal voltage sampling circuit series branch comprises: a power output link and a data communication link; in the power output link part, each The output circuits of the solar power generation units are connected in series, that is, the positive pole of the power supply of the first solar power generation unit is connected to the negative pole of the second solar power generation unit, the negative pole of the second solar power generation unit is connected to the positive pole of the power supply of the third solar power generation unit, and so on, and the positive pole or negative pole of the last solar power generation unit and the negative pole or positive pole of the first solar power generation unit form the power output port of the first branch; in the data communication part, the optimization processing circuit (3) of each solar power generation unit is electrically connected to the power line trunk communication link (8) through the power line branch communication link (5) through its own branch PLC power line communication module (4), and the central processor (6) is electrically connected to the power line trunk communication link (8) through the trunk PLC power line communication module (9), and the central processor (6) obtains the voltage of the photovoltaic module (1) in each solar power generation unit. The optimization processing circuit (3) of each solar power generation unit reports the voltage value to the central processor (6) through the PLC.

[0012] The existing photovoltaic module maximum power point tracking technology has the following disadvantages: the dual sensor optimizer using current and voltage measurement values ​​introduces an increase in measurement cost and a large measurement power consumption; the single sensor optimizer using voltage measurement values ​​is difficult to ensure the tracking point accuracy and stability of the MPPT; and there is no use of the data transmission capability of the communication channel to reduce the measurement cost and measurement power consumption of the MPPT.

[0013] The utility model provides a maximum power point tracking device for components in a photovoltaic string, which is used to overcome at least one of the shortcomings of the existing photovoltaic component maximum power point tracking technology, namely, a dual sensor optimizer using current and voltage measurement values ​​introduces an increase in measurement cost and a large measurement power consumption, a single sensor optimizer using voltage measurement values ​​is difficult to ensure the tracking point accuracy and stability of the MPPT, and there is no data transmission capability of a communication channel to reduce the measurement cost and measurement power consumption of the MPPT. Summary of the invention

[0014] The utility model provides a maximum power point tracking device for components in a photovoltaic string, which is used to overcome at least one of the shortcomings of the existing photovoltaic component maximum power point tracking technology, namely, a dual sensor optimizer using current and voltage measurement values ​​introduces an increase in measurement cost and a large measurement power consumption, a single sensor optimizer using voltage measurement values ​​is difficult to ensure the tracking point accuracy and stability of the MPPT, and there is no data transmission capability of a communication channel to reduce the measurement cost and measurement power consumption of the MPPT.

[0015] The utility model provides a method for tracking the maximum power point of a component in a photovoltaic string, comprising the following steps:

[0016] Step S110, measuring a DC bus current at a first position of a DC bus of a photovoltaic string, and measuring a photovoltaic module voltage at a power output port position of a photovoltaic module included in the photovoltaic string, wherein the power output port position of the photovoltaic module is a different spatial position from the first position;

[0017] Step S120, using a wired or wireless channel to send the measured value of the DC bus current obtained at the first position of the DC bus to a maximum power point tracking unit facing the photovoltaic assembly and located at the power output port of the photovoltaic assembly;

[0018] Step S130 : The maximum power point tracking unit for the photovoltaic assembly performs maximum power point tracking on the corresponding photovoltaic assembly using the measured value of the photovoltaic assembly voltage at the power output port of the photovoltaic assembly and the measured value of the DC bus current obtained at the first position.

[0019] The utility model provides a maximum power point tracking device for components in a photovoltaic string, comprising:

[0020] A bus current measurement circuit (11), a voltage measurement module (22), an MPPT module (21), a second communication module (23), and at least one of a third communication module (61), a first communication module (12) and a main communication module; characterized in that:

[0021] A bus current measurement circuit (11), used for measuring the DC bus current at a first position of the photovoltaic string DC bus, comprising a current sensor and a signal conditioning circuit;

[0022] A voltage measurement module (22) is used to measure the voltage of the photovoltaic module at the power output port position of the photovoltaic module included in the photovoltaic string, and comprises a voltage signal sampling circuit and a signal conditioning circuit; the power output port position of the photovoltaic module is a spatial position different from the first position;

[0023] A second communication module (23) is located at a power output port of the photovoltaic module, and is used to receive a bus current value obtained by measuring the DC bus current at a first position of the photovoltaic string DC bus from at least one of the third communication module (61), the first communication module (12), and the main communication module, and transmit the bus current value to a corresponding maximum power point tracking unit MPPT module (21) facing the photovoltaic module, and comprises a communication receiving module using a wired channel or a wireless channel;

[0024] The MPPT module (21) is a maximum power point tracking unit for a photovoltaic module, which uses a measured value of a photovoltaic module voltage at a power output port of the photovoltaic module and a measured value of a DC bus current obtained at a first position to perform maximum power point tracking on a corresponding photovoltaic module, and comprises a maximum power point determination circuit and a power point adjustment circuit.

[0025] The utility model provides a photovoltaic string component maximum power point tracking device, which can overcome at least one of the following shortcomings of the existing photovoltaic component maximum power point tracking technology: the dual sensor optimizer using current and voltage measurement values ​​introduces an increase in measurement cost and a large measurement power consumption, the single sensor optimizer using voltage measurement values ​​is difficult to ensure the tracking point accuracy and stability of the MPPT, and the lack of data transmission capabilities of the communication channel to reduce the measurement cost and measurement power consumption of the MPPT. The MPPT current measurement power consumption and cost are reduced.

[0026] Other features and advantages of the present invention will be described in the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A flow chart of a maximum power point tracking method in a photovoltaic string is provided for a specific implementation mode of the utility model;

[0028] Figure 2 A schematic diagram of a configuration mode of a maximum power point tracking device in a photovoltaic string provided for a specific implementation mode of the utility model;

[0029] Figure 3 The present invention is a schematic diagram of a second configuration of a maximum power point tracking device in a photovoltaic string according to a specific implementation manner of the present invention.

[0030] In the figure, 1. bus current measurement module; 2. power optimizer; 3. photovoltaic module; 4. inverter; 5. DC bus; 6. power optimizer supporting current measurement;

[0031] 11. bus current measurement circuit; 12. first communication module;

[0032] 21. MPPT module; 22. voltage measurement module; 23. second communication module; 24. DC / DC conversion circuit;

[0033] 61. A third communication module; 62. A current sensor. DETAILED DESCRIPTION

[0034] The utility model provides a maximum power point tracking device for components in a photovoltaic string, which is used to overcome at least one of the shortcomings of the existing photovoltaic component maximum power point tracking technology, namely, a dual sensor optimizer using current and voltage measurement values ​​introduces an increase in measurement cost and a large measurement power consumption, a single sensor optimizer using voltage measurement values ​​is difficult to ensure the tracking point accuracy and stability of the MPPT, and there is no data transmission capability of a communication channel to reduce the measurement cost and measurement power consumption of the MPPT.

[0035] In order to make the purpose, technical solution and advantages of the utility model more clear, the specific implementation of the utility model will be described in detail below with reference to the accompanying drawings. It should be noted that the specific implementation and features in the specific implementation in this application can be combined with each other arbitrarily without conflict.

[0036] The method and device provided by the utility model are described below with reference to the accompanying drawings.

[0037] Specific implementation method 1: Example of a maximum power point tracking method for a photovoltaic string component

[0038] The utility model provides a method for tracking the maximum power point of a photovoltaic string component. Figure 1 As shown, the following steps are included:

[0039] Step S110, measuring a DC bus current at a first position of a DC bus of a photovoltaic string, and measuring a photovoltaic module voltage at a power output port position of a photovoltaic module included in the photovoltaic string, wherein the power output port position of the photovoltaic module is a different spatial position from the first position;

[0040] Step S120, using a wired or wireless channel to send the measured value of the DC bus current obtained at the first position of the DC bus to a maximum power point tracking unit facing the photovoltaic assembly and located at the power output port of the photovoltaic assembly;

[0041] Step S130 : The maximum power point tracking unit for the photovoltaic assembly performs maximum power point tracking on the corresponding photovoltaic assembly using the measured value of the photovoltaic assembly voltage at the power output port of the photovoltaic assembly and the measured value of the DC bus current obtained at the first position.

[0042] The method provided in the specific embodiment of the utility model is applicable to the output power optimization of a photovoltaic string composed of a plurality of photovoltaic modules (3) connected in series, wherein each photovoltaic module (3) in the photovoltaic string is configured with a maximum power point tracking module (MPPT: Maximum Power Point Tracking) for optimizing the output power of the photovoltaic module, and in the specific embodiment, the maximum power point tracking module is identified as an MPPT module (21).

[0043] The maximum power point tracking method provided in this specific embodiment belongs to a maximum power point tracking method that uses both voltage measurement and current measurement, and uses voltage measurement and current measurement to calculate the output power of a photovoltaic module (3), estimate the maximum power point position, and track the maximum power point position.

[0044] The core technical idea of ​​the maximum power point tracking method provided in this specific embodiment is: utilizing the rule that different photovoltaic modules (3) connected in series in a photovoltaic string with series output have the same output current, when obtaining the output current value of a single photovoltaic module (3), avoiding output current measurement at the output end of each photovoltaic module (3), but obtaining the current value on the DC bus at a specific position of the DC bus of the series-connected photovoltaic modules (3), and using the current value obtained at the specific position as the output current value of different photovoltaic modules (3) connected in series on the bus, thereby reducing the number of DC current measurement points in the photovoltaic string, thereby reducing the cost of the current measurement circuit and reducing the power loss introduced by the current measurement.

[0045] In this specific embodiment, a communication channel is used to obtain a current value on a DC bus at a specific position of each photovoltaic module (3) connected in series and send it to a power optimizer (2) arranged in the photovoltaic string and corresponding to the specific photovoltaic module. The MPPT module (21) uses the current value to perform a maximum power point tracking operation.

[0046] The power optimizer (2) provided in this specific embodiment does not have the ability to measure the DC bus current, nor does it have the ability to measure the current at the output end of the photovoltaic module; in other words, the power optimizer (2) provided in this specific embodiment does not include a circuit for measuring the DC bus current, nor does it include a circuit for measuring the current at the output end of the photovoltaic module.

[0047] In this specific embodiment, in order to ensure that the current value on the DC bus obtained at a specific position on the DC bus of each photovoltaic module (3) connected in series corresponds to the output voltage value of different photovoltaic modules (3) in time, a method for using a communication channel to achieve time synchronization between current measurement and voltage measurement is provided.

[0048] The photovoltaic string comprises two or more photovoltaic modules (3), and the output ends of the photovoltaic modules (3) are connected in a direct current series manner;

[0049] The DC bus (5) is a conductor that connects the output voltages of two or more photovoltaic modules in series. The DC bus transmits the series output voltage and current of the photovoltaic modules to the DC input terminal of the inverter (4).

[0050] The output end of the photovoltaic module (3) is electrically connected to the DC input end of the DC / DC conversion circuit (24), and the DC output end of the DC / DC conversion circuit (24) is electrically connected to the DC bus (5);

[0051] The output power of the photovoltaic assembly (3) is sent to the DC bus (5) via a DC / DC conversion circuit (24).

[0052] The DC / DC conversion circuit (24) is electrically connected to the MPPT module (21), and the electrical connection is used for the MPPT module (21) to adjust the output power of the DC / DC conversion circuit (24).

[0053] The DC / DC conversion circuit (24) is a step-down circuit or a step-up circuit; a specific implementation of a step-up circuit is a BOOST circuit; a specific implementation of a step-down circuit is a BUCK circuit.

[0054] The power output port position of the photovoltaic module is the position of the voltage output terminal of the photovoltaic module or the voltage output terminal position of the DC / DC conversion circuit (24);

[0055] The first position is located on a DC bus (5) connecting the output end of the photovoltaic string and the DC input end of the inverter (4); or located on a DC bus (5) from the DC input end of the inverter (4) to the input end of the DC / AC conversion circuit of the inverter; or located on a power output loop from the output end of the DC / DC conversion circuit (24) to the DC bus (5);

[0056] Specifically, the first position is located between the output end of the photovoltaic string and the input end of the DC / AC inverter (4); or is located inside the DC / AC inverter (4); or is located inside a power optimizer (6) supporting current measurement facing the photovoltaic module.

[0057] Usually, only one first position is used to measure the DC bus current, and two or more power output port positions of the photovoltaic modules are used to measure the photovoltaic module voltages respectively.

[0058] The method provided in this specific embodiment, wherein:

[0059] The DC bus current is measured at a first position of the DC bus of the photovoltaic string, and the photovoltaic module voltage is measured at a power output port position of the photovoltaic module included in the photovoltaic string, specifically including:

[0060] Using a wired or wireless channel to send a measurement synchronization signal, under the synchronization of the measurement synchronization signal, the DC bus current is measured at a first position of the DC bus of the photovoltaic string; and / or, the photovoltaic module voltage is measured at a power output port position of the photovoltaic module included in the photovoltaic string;

[0061] The measurement synchronization signal includes measurement trigger information or measurement start time information.

[0062] The measurement synchronization signal is sent in a broadcasting manner to two or more second communication modules (23) configured at the power output port position of the photovoltaic component. The measurement synchronization signal is a communication synchronization signal in a communication link or a dedicated synchronization signal for synchronizing the first position to perform DC bus current measurement and the photovoltaic component voltage measurement at the power output port position of the photovoltaic component included in the photovoltaic string.

[0063] When the measurement synchronization signal is sent by the communication module configured on the main communication node to any one of the third communication module (61) and the first communication module (12) at the first position, and to the second communication module (23) configured at the power output port position of the photovoltaic component, the measurement synchronization signal is a communication synchronization signal sent by the communication module configured on the main communication node or a dedicated synchronization signal for synchronizing the first position to measure the DC bus current and the photovoltaic component voltage at the power output port position of the photovoltaic component included in the photovoltaic string.

[0064] When the measurement synchronization signal is sent by the first communication module (12) arranged at the first position to the second communication module (23) arranged at the power output port position of the photovoltaic component, the measurement number information includes at least one of the number of times the photovoltaic component voltage is measured at the power output port position of the photovoltaic component and the measurement interval time information;

[0065] When the measurement synchronization signal is sent by the third communication module (61) configured at the first position to the second communication module (23) configured at the power output port position of the photovoltaic component, the measurement number information includes at least one of the number of times the photovoltaic component voltage is measured at the power output port position of the photovoltaic component and the measurement interval time information;

[0066] In a manner in which the measurement synchronization signal is sent by a communication module configured on the main communication node to a first communication module (12) at a first position and a second communication module (23) configured at a power output port position of a photovoltaic component, measurement number information and measurement interval time information are also sent by the communication module on the main communication node; the measurement number information includes at least one of the number of times the DC bus current is measured at the first position and the number of times the photovoltaic component voltage is measured at the power output port position of the photovoltaic component included in the photovoltaic string; the measurement interval time information includes at least one of the interval time information of the DC bus current measurement at the first position and the measurement interval time information of the photovoltaic component voltage measurement at the power output port position of the photovoltaic component included in the photovoltaic string; the main communication node is an access point for the first communication module (12) and the second communication module (23);

[0067] In a manner in which the measurement synchronization signal is sent by a communication module configured on a main communication node to a third communication module (61) at a first position and a second communication module (23) configured at a power output port position of a photovoltaic component, measurement number information and measurement interval time information are also sent by the communication module on the main communication node; the measurement number information includes at least one of the number of times direct current bus current measurements are performed at the first position and the number of times photovoltaic component voltage measurements are performed at the power output port position of the photovoltaic component included in the photovoltaic string; the measurement interval time information includes at least one of the interval time information of direct current bus current measurements at the first position and the measurement interval time information of photovoltaic component voltage measurements at the power output port position of the photovoltaic component included in the photovoltaic string; the main communication node is an access point for the first communication module (12) and the third communication module (61).

[0068] The bus current measurement circuit (11) comprises a current measurement resistor or a current measurement Hall device;

[0069] The current measuring resistor is a resistor connected in series in the loop where the busbar is located, and the value range of the current measuring resistor is between 5 and 100 (milliohms).

[0070] The current measurement Hall device is a giant magnetic device, which is used for coupling measurement of the current in the loop where the busbar is located.

[0071] The method provided in this specific embodiment, wherein:

[0072] The using a wired or wireless channel to send the measurement synchronization signal specifically includes:

[0073] Using any one of the first communication module (12) and the third communication module (61) at the first position to send a measurement synchronization signal to a second communication module (23) arranged at the power output port position of the photovoltaic component through a wired or wireless channel; or

[0074] A communication module on the main communication node is used to send a measurement synchronization signal to a second communication module (23) connected to the main communication node, and any one of a first communication module (12) and a third communication module (61) through a wired or wireless channel.

[0075] The wired channel includes a power line communication (PLC) channel that performs signal modulation on the DC bus or a wired channel provided by a communication conductor independent of the DC bus.

[0076] The wired channel provided by the communication conductor independent of the DC bus includes a wired channel using a public communication protocol or a private communication protocol; a specific example of a wired channel using a shared communication protocol is a wired channel using an Ethernet protocol.

[0077] The wireless channel includes a wireless channel using a public communication protocol or a wireless channel using a private protocol.

[0078] Specific examples of the wireless channel using the public communication protocol include: a wireless channel using the WLAN communication protocol, a wireless channel using the Bluetooth communication protocol, and a wireless channel using the Rola communication protocol.

[0079] The method provided in this specific embodiment, wherein:

[0080] The method of using a wired or wireless channel to send the measured value of the DC bus current obtained at the first position of the DC bus to a maximum power point tracking unit facing the photovoltaic assembly and located at the power output port of the photovoltaic assembly specifically includes:

[0081] The first communication module (12) or the third communication module (61) at the first position uses a wired channel or a wireless channel to broadcast the measured value of the DC bus current to the MPPT module (21) in the power optimizer (2) via the second communication module (23) in the power optimizer (2) located at the power output port of the photovoltaic module; or

[0082] The first communication module (12) or the third communication module (61) at the first position uses a wired channel or a wireless channel to send the measured value of the DC bus current to the communication module on the main communication node, and the communication module on the main communication node sends the received measured value of the DC bus current to the MPPT module (21) in the power optimizer (2) via the second communication module (23) in the power optimizer (2) located at the power output port of the photovoltaic module.

[0083] The main communication node is located outside the photovoltaic string bus.

[0084] In this specific embodiment, the communication module on the main communication node, the third communication module (61) at the first position, and the second communication module (23) configured at the power output port position of the photovoltaic component simultaneously support the same wired communication protocol, or simultaneously support the same wireless communication protocol.

[0085] The measured value of the DC bus current is sent in a specified bus current frame format, and one bus current frame includes the measured value of the DC bus current and the measurement time of the measured value;

[0086] A bus current frame includes one or more DC bus current measurement values ​​and measurement time information of the measurement values.

[0087] The method provided in this specific embodiment, wherein:

[0088] The maximum power point tracking unit for the photovoltaic assembly uses the photovoltaic assembly voltage measurement value at the power output port position of the photovoltaic assembly and the DC bus current measurement value obtained at the first position to perform maximum power point tracking on the corresponding photovoltaic assembly, specifically including:

[0089] The MPPT module (21) in the power optimizer (2) uses the photovoltaic module voltage measurement value obtained by measuring the photovoltaic module voltage at the power output port position of the photovoltaic module by the voltage measurement module (22) in the power optimizer (2), and uses the DC bus current measurement value obtained at the first position received by the second communication module (23) to calculate the power output value of the photovoltaic module, and determines the position of the maximum power point of the photovoltaic module according to the power output values ​​at different times.

[0090] The calculating of the power output value of the photovoltaic module comprises using the measured value of the DC bus current at different times and the corresponding measured value of the photovoltaic module voltage at the time to calculate the power output value of the photovoltaic module at the time, and obtaining a group of power output values ​​of the photovoltaic module at different times;

[0091] Determining the position of the maximum power point of the photovoltaic assembly according to the power output values ​​at different times includes using a group of power output values ​​of the photovoltaic assembly at different times to determine the position of the maximum power point of the photovoltaic assembly.

[0092] The method of using a group of power output values ​​of photovoltaic modules at different times to determine the position of the maximum power point of the photovoltaic module specifically includes: using one or more of extreme seeking control, perturb and observe, modified perturb and observe, incremental conductance, two-mode MPPT control, ripple correction control and particle swarm optimization to determine the position of the maximum power point of the photovoltaic module.

[0093] The position of the maximum power point of the photovoltaic module is the output current and output voltage corresponding to when the photovoltaic module outputs the maximum power.

[0094] Specific implementation method 2: Example of a maximum power point tracking device for a photovoltaic string

[0095] The utility model provides a specific implementation of a maximum power point tracking device for a photovoltaic string component, comprising:

[0096] It comprises a bus current measurement circuit (11), a voltage measurement module (22), an MPPT module (21), a second communication module (23), and at least one of a third communication module (61), a first communication module (12) and a main communication module; wherein:

[0097] A bus current measurement circuit (11), used for measuring the DC bus current at a first position of the photovoltaic string DC bus, comprising a current sensor and a signal conditioning circuit;

[0098] A voltage measurement module (22) is used to measure the voltage of the photovoltaic module at the power output port position of the photovoltaic module included in the photovoltaic string, and comprises a voltage signal sampling circuit and a signal conditioning circuit; the power output port position of the photovoltaic module is a spatial position different from the first position;

[0099] A second communication module (23) is located at a power output port of the photovoltaic module, and is used to receive a bus current value obtained by measuring the DC bus current at a first position of the photovoltaic string DC bus from at least one of the third communication module (61), the first communication module (12), and the main communication module, and transmit the bus current value to a corresponding maximum power point tracking unit MPPT module (21) facing the photovoltaic module, and comprises a communication receiving module using a wired channel or a wireless channel;

[0100] The MPPT module (21) is a maximum power point tracking unit for a photovoltaic module, which uses a measured value of a photovoltaic module voltage at a power output port of the photovoltaic module and a measured value of a DC bus current obtained at a first position to perform maximum power point tracking on a corresponding photovoltaic module, and comprises a maximum power point determination circuit and a power point adjustment circuit.

[0101] The maximum power point determination circuit includes a digital processor for executing a maximum power point search and tracking algorithm;

[0102] The power point adjustment circuit comprises a circuit for controlling the duty cycle of the PWM waveform of the DC / DC conversion circuit (24), and is used for changing the duty cycle of the DC / DC conversion circuit (24).

[0103] The voltage measurement module (22), the MPPT module (21), the second communication module (23), and the DC / DC conversion circuit (24) constitute a power optimizer (2) for photovoltaic panel assemblies;

[0104] The voltage measurement module (22), the MPPT module (21), the bus current measurement circuit (11), the current sensor (62), the DC / DC conversion circuit (24), and the third communication module (61) constitute a power optimizer (6) supporting current measurement for photovoltaic modules.

[0105] The bus current measurement circuit (11) and the first communication module (12) constitute a line current measurement module (1).

[0106] The power optimizer (2) for photovoltaic panel components, the power optimizer (6) for photovoltaic components supporting current measurement, and the current measurement module (1) are installed at different positions in the photovoltaic string, and transmit the measured value or measurement control signal of the bus current to each other via a wired or wireless channel.

[0107] The method provided in the specific embodiment of the utility model is applicable to the output power optimization of a photovoltaic string composed of a plurality of photovoltaic modules (3) connected in series, wherein each photovoltaic module (3) in the photovoltaic string is configured with a maximum power point tracking module (MPPT: Maximum Power Point Tracking) for optimizing the output power of the photovoltaic module, and in the specific embodiment, the maximum power point tracking module is identified as an MPPT module (21).

[0108] The maximum power point tracking device provided in this specific embodiment uses both voltage measurement and current measurement to perform maximum power point tracking, and uses voltage measurement and current measurement to calculate the output power of the photovoltaic module (3), estimate the maximum power point position and track the maximum power point position.

[0109] The core technical idea of ​​the maximum power point tracking device provided in this specific embodiment is: utilizing the rule that different photovoltaic modules (3) connected in series in a photovoltaic string with series output have the same output current, when obtaining the output current value of a single photovoltaic module (3), avoiding output current measurement at the output end of each photovoltaic module (3), but obtaining the current value on the DC bus at a specific position of the DC bus of the series-connected photovoltaic modules (3), and using the current value obtained at the specific position as the output current value of different photovoltaic modules (3) connected in series on the bus, thereby reducing the number of DC current measurement points in the photovoltaic string, thereby reducing the cost of the current measurement circuit and reducing the power loss introduced by the current measurement.

[0110] In this specific embodiment, a communication channel is used to obtain a current value on a DC bus at a specific position of each photovoltaic module (3) connected in series and send it to a power optimizer (2) arranged in the photovoltaic string and corresponding to the specific photovoltaic module. The MPPT module (21) uses the current value to perform a maximum power point tracking operation.

[0111] The power optimizer (2) provided in this specific embodiment does not have the ability to measure the DC bus current, nor does it have the ability to measure the current at the output end of the photovoltaic module; in other words, the power optimizer (2) provided in this specific embodiment does not include a circuit for measuring the DC bus current, nor does it include a circuit for measuring the current at the output end of the photovoltaic module.

[0112] In this specific embodiment, in order to ensure that the current value on the DC bus obtained at a specific position on the DC bus of each photovoltaic module (3) connected in series corresponds to the output voltage value of different photovoltaic modules (3) in time, a method for using a communication channel to achieve time synchronization between current measurement and voltage measurement is provided.

[0113] The photovoltaic string comprises two or more photovoltaic modules (3), and the output ends of the photovoltaic modules (3) are connected in a direct current series manner;

[0114] The DC bus (5) is a conductor that connects the output voltages of two or more photovoltaic modules in series. The DC bus transmits the series output voltage and current of the photovoltaic modules to the DC input terminal of the inverter (4).

[0115] The output end of the photovoltaic module (3) is electrically connected to the DC input end of the DC / DC conversion circuit (24), and the DC output end of the DC / DC conversion circuit (24) is electrically connected to the DC bus (5);

[0116] The output power of the photovoltaic assembly (3) is sent to the DC bus (5) via a DC / DC conversion circuit (24).

[0117] The DC / DC conversion circuit (24) is electrically connected to the MPPT module (21), and the electrical connection is used for the MPPT module (21) to adjust the output power of the DC / DC conversion circuit (24).

[0118] The DC / DC conversion circuit (24) is a step-down circuit or a step-up circuit; a specific implementation of a step-up circuit is a BOOST circuit; a specific implementation of a step-down circuit is a BUCK circuit.

[0119] The power output port position of the photovoltaic module is the position of the voltage output terminal of the photovoltaic module or the voltage output terminal position of the DC / DC conversion circuit (24);

[0120] The first position is located on a DC bus (5) connecting the output end of the photovoltaic string and the DC input end of the inverter (4); or located on a DC bus (5) from the DC input end of the inverter (4) to the input end of the DC / AC conversion circuit of the inverter; or located on a power output loop from the output end of the DC / DC conversion circuit (24) to the DC bus (5);

[0121] Specifically, the first position is located between the output end of the photovoltaic string and the input end of the DC / AC inverter (4); or is located inside the DC / AC inverter (4); or is located inside a power optimizer (6) supporting current measurement facing the photovoltaic module.

[0122] Usually, only one first position is used to measure the DC bus current, and two or more power output port positions of the photovoltaic modules are used to measure the photovoltaic module voltages respectively.

[0123] The device provided in this specific embodiment, wherein:

[0124] The bus current measurement circuit (11) performs a DC bus current measurement operation at a first position of the DC bus of the photovoltaic string, and the voltage measurement module (22) performs a photovoltaic module voltage measurement operation at a power output port position of the photovoltaic module included in the photovoltaic string, specifically comprising:

[0125] At least one of the third communication module (61), the first communication module (12) and the main communication module uses a wired or wireless channel to send a measurement synchronization signal to the second communication module (23), and in synchronization with the measurement synchronization signal, the bus current measurement circuit (11) performs DC bus current measurement at a first position of the photovoltaic string DC bus; and / or the voltage measurement module (22) performs photovoltaic module voltage measurement at a power output port position of a photovoltaic module included in the photovoltaic string;

[0126] The measurement synchronization signal includes measurement trigger information or measurement start time information.

[0127] The measurement synchronization signal is sent in a broadcasting manner to two or more second communication modules (23) configured at the power output port position of the photovoltaic component. The measurement synchronization signal is a communication synchronization signal in a communication link or a dedicated synchronization signal for synchronizing the first position to perform DC bus current measurement and the photovoltaic component voltage measurement at the power output port position of the photovoltaic component included in the photovoltaic string.

[0128] When the measurement synchronization signal is sent by the communication module configured on the main communication node to any one of the third communication module (61) and the first communication module (12) at the first position, and to the second communication module (23) configured at the power output port position of the photovoltaic component, the measurement synchronization signal is a communication synchronization signal sent by the communication module configured on the main communication node or a dedicated synchronization signal for synchronizing the first position to measure the DC bus current and the photovoltaic component voltage at the power output port position of the photovoltaic component included in the photovoltaic string.

[0129] When the measurement synchronization signal is sent by the first communication module (12) arranged at the first position to the second communication module (23) arranged at the power output port position of the photovoltaic component, the measurement number information includes at least one of the number of times the photovoltaic component voltage is measured at the power output port position of the photovoltaic component and the measurement interval time information;

[0130] When the measurement synchronization signal is sent by the third communication module (61) configured at the first position to the second communication module (23) configured at the power output port position of the photovoltaic component, the measurement number information includes at least one of the number of times the photovoltaic component voltage is measured at the power output port position of the photovoltaic component and the measurement interval time information;

[0131] In a manner in which the measurement synchronization signal is sent by a communication module configured on the main communication node to a first communication module (12) at a first position and a second communication module (23) configured at a power output port position of a photovoltaic component, measurement number information and measurement interval time information are also sent by the communication module on the main communication node; the measurement number information includes at least one of the number of times the DC bus current is measured at the first position and the number of times the photovoltaic component voltage is measured at the power output port position of the photovoltaic component included in the photovoltaic string; the measurement interval time information includes at least one of the interval time information of the DC bus current measurement at the first position and the measurement interval time information of the photovoltaic component voltage measurement at the power output port position of the photovoltaic component included in the photovoltaic string; the main communication node is an access point for the first communication module (12) and the second communication module (23);

[0132] In a manner in which the measurement synchronization signal is sent by a communication module configured on a main communication node to a third communication module (61) at a first position and a second communication module (23) configured at a power output port position of a photovoltaic component, measurement number information and measurement interval time information are also sent by the communication module on the main communication node; the measurement number information includes at least one of the number of times direct current bus current measurements are performed at the first position and the number of times photovoltaic component voltage measurements are performed at the power output port position of the photovoltaic component included in the photovoltaic string; the measurement interval time information includes at least one of the interval time information of direct current bus current measurements at the first position and the measurement interval time information of photovoltaic component voltage measurements at the power output port position of the photovoltaic component included in the photovoltaic string; the main communication node is an access point for the first communication module (12) and the third communication module (61).

[0133] The bus current measurement circuit (11) comprises a current measurement resistor or a current measurement Hall device;

[0134] The current measuring resistor is a resistor connected in series in the loop where the busbar is located, and the value range of the current measuring resistor is between 5 and 100 (milliohms).

[0135] The current measurement Hall device is a giant magnetic device, which is used for coupling measurement of the current in the loop where the busbar is located.

[0136] The device provided in this specific embodiment, wherein:

[0137] The operation of at least one of the third communication module (61), the first communication module (12) and the main communication module sending a measurement synchronization signal to the second communication module (23) using a wired or wireless channel specifically comprises:

[0138] Using any one of the first communication module (12) and the third communication module (61) at the first position to send a measurement synchronization signal to a second communication module (23) arranged at the power output port position of the photovoltaic component through a wired or wireless channel; or

[0139] A communication module on the main communication node is used to send a measurement synchronization signal to a second communication module (23) connected to the main communication node, and any one of a first communication module (12) and a third communication module (61) through a wired or wireless channel.

[0140] The wired channel includes a power line communication (PLC) channel that performs signal modulation on the DC bus or a wired channel provided by a communication conductor independent of the DC bus.

[0141] The wired channel provided by the communication conductor independent of the DC bus includes a wired channel using a public communication protocol or a private communication protocol; a specific example of a wired channel using a shared communication protocol is a wired channel using an Ethernet protocol.

[0142] The wireless channel includes a wireless channel using a public communication protocol or a wireless channel using a private protocol.

[0143] Specific examples of the wireless channel using the public communication protocol include: a wireless channel using the WLAN communication protocol, a wireless channel using the Bluetooth communication protocol, and a wireless channel using the Rola communication protocol.

[0144] The device provided in this specific embodiment, wherein:

[0145] The second communication module (23) receives a bus current value obtained by measuring a DC bus current at a first position of a photovoltaic string DC bus from at least one of the third communication module (61), the first communication module (12) and the main communication module, and transmits the bus current value to a corresponding maximum power point tracking unit MPPT module (21) for a photovoltaic assembly, specifically comprising:

[0146] The first communication module (12) or the third communication module (61) at the first position uses a wired channel or a wireless channel to broadcast the measured value of the DC bus current to the MPPT module (21) in the power optimizer (2) via the second communication module (23) in the power optimizer (2) located at the power output port of the photovoltaic module; or

[0147] The first communication module (12) or the third communication module (61) at the first position uses a wired channel or a wireless channel to send the measured value of the DC bus current to the communication module on the main communication node, and the communication module on the main communication node sends the received measured value of the DC bus current to the MPPT module (21) in the power optimizer (2) via the second communication module (23) in the power optimizer (2) located at the power output port of the photovoltaic module.

[0148] The main communication node is located outside the photovoltaic string bus.

[0149] In this specific embodiment, the communication module on the main communication node, the third communication module (61) at the first position, and the second communication module (23) configured at the power output port position of the photovoltaic component simultaneously support the same wired communication protocol, or simultaneously support the same wireless communication protocol.

[0150] The measured value of the DC bus current is sent in a specified bus current frame format, and one bus current frame includes the measured value of the DC bus current and the measurement time of the measured value;

[0151] A bus current frame includes one or more DC bus current measurement values ​​and measurement time information of the measurement values.

[0152] The device provided in this specific embodiment, wherein:

[0153] The maximum power point tracking unit MPPT module (21) for photovoltaic components uses the photovoltaic component voltage measurement value at the power output port position of the photovoltaic component and the DC bus current measurement value obtained at the first position to perform a maximum power point tracking operation on the corresponding photovoltaic component, specifically comprising:

[0154] The MPPT module (21) in the power optimizer (2) uses the photovoltaic module voltage measurement value obtained by measuring the photovoltaic module voltage at the power output port position of the photovoltaic module by the voltage measurement module (22) in the power optimizer (2), and uses the DC bus current measurement value obtained at the first position received by the second communication module (23) to calculate the power output value of the photovoltaic module, and determines the position of the maximum power point of the photovoltaic module according to the power output values ​​at different times.

[0155] The calculating of the power output value of the photovoltaic module comprises using the measured value of the DC bus current at different times and the corresponding measured value of the photovoltaic module voltage at the time to calculate the power output value of the photovoltaic module at the time, and obtaining a group of power output values ​​of the photovoltaic module at different times;

[0156] Determining the position of the maximum power point of the photovoltaic assembly according to the power output values ​​at different times includes using a group of power output values ​​of the photovoltaic assembly at different times to determine the position of the maximum power point of the photovoltaic assembly.

[0157] The method of using a group of power output values ​​of photovoltaic modules at different times to determine the position of the maximum power point of the photovoltaic module specifically includes: using one or more of extreme seeking control, perturb and observe, modified perturb and observe, incremental conductance, two-mode MPPT control, ripple correction control and particle swarm optimization to determine the position of the maximum power point of the photovoltaic module.

[0158] The position of the maximum power point of the photovoltaic module is the output current and output voltage corresponding to when the photovoltaic module outputs the maximum power.

[0159] The photovoltaic module maximum power point tracking device provided in this specific implementation manner is shown in FIG. Figure 2 and Figure 3 As shown, it includes a power optimizer (2), a bus current measurement module (1) or a power optimizer (6) supporting current measurement.

[0160] Furthermore, the photovoltaic module maximum power point tracking device provided in this specific embodiment also includes a main communication node ( Figure 2 and Figure 3 (not shown), the main communication node is an access point of the first communication module (12) and the second communication module (23); or an access point of the second communication module (23) and the third communication module (61).

[0161] A specific working mode of the master communication node is that when the measurement synchronization signal is sent by the communication module configured on the master communication node to the first communication module (12) at the first position and the second communication module (23) configured at the power output port position of the photovoltaic component, the measurement number information and the measurement interval time information are also sent by the communication module on the master communication node; the measurement number information includes at least one of the number of times the DC bus current is measured at the first position and the number of times the photovoltaic component voltage is measured at the power output port position of the photovoltaic component included in the photovoltaic string; and the measurement interval time information includes at least one of the interval time information of the DC bus current measurement at the first position and the measurement interval time information of the photovoltaic component voltage measurement at the power output port position of the photovoltaic component included in the photovoltaic string.

[0162] As a specific implementation method of maximum power point tracking of photovoltaic components, see Figure 2 As shown, the system structure includes: two or more photovoltaic modules (3) are connected in series using their corresponding power optimizers (2) to form a photovoltaic sub-string without bus current measurement function, and the photovoltaic sub-string without bus current measurement function is connected in series with a photovoltaic module (3) through a power optimizer (6) supporting current measurement to form a photovoltaic string provided by the utility model that uses a communication channel to realize current measurement optimization in maximum power point tracking of photovoltaic modules.

[0163] In this specific implementation, the power optimizer (2) comprises a DC / DC conversion circuit (24), a voltage measurement module (22), an MPPT module (21) and a second communication module (23);

[0164] A power optimizer (6) supporting current measurement comprises a DC / DC conversion circuit (24), a voltage measurement module (22), an MPPT module (21), a bus current measurement circuit (11), a current sensor (62) and a third communication module (61); wherein the current sensor is a 40 milliohm resistor.

[0165] exist Figure 2 In the implementation method provided, the photovoltaic string DC bus (5) is electrically connected to the DC input end of the inverter (4), and the inverter (4) converts the DC power sent by the DC bus (5) into AC power and then sends it to the AC power grid through output terminals T1 and T2.

[0166] The third communication module (61) sends a measurement synchronization signal and a measurement control signal to a plurality of second communication modules (23) in the string through a wireless channel, wherein the measurement control signal includes at least one of measurement start time information, measurement number information and measurement interval information;

[0167] Furthermore, the third communication module (61) sends the bus current value measured by the bus current measurement circuit (11) included in the power optimizer (6) supporting current measurement to the plurality of second communication modules (23) in the string through a wireless channel.

[0168] Furthermore, the MPPT module (21) included in the power optimizer (2) uses the bus current value received by the second communication module (23) to perform maximum power point tracking on the photovoltaic component.

[0169] As another specific implementation method of maximum power point tracking of photovoltaic components, see Figure 3 As shown, the system structure includes: two or more photovoltaic modules (3) are connected in series using their corresponding power optimizers (2) to form a photovoltaic string without bus current measurement function, and a bus current measurement module (1) is connected in series to the output bus of the photovoltaic string without bus current measurement function, and the bus current measurement module (1) includes a bus current measurement circuit (11) and a first communication module (12). The photovoltaic string without bus current measurement function and the bus current measurement module (1) form a photovoltaic string for realizing current measurement optimization in maximum power point tracking of photovoltaic modules using a communication channel provided by the utility model.

[0170] In this specific implementation, the power optimizer (2) comprises a DC / DC conversion circuit (24), a voltage measurement module (22), an MPPT module (21) and a second communication module (23);

[0171] exist Figure 3 In the implementation method provided, the photovoltaic string DC bus (5) is electrically connected to the DC input end of the inverter (4), and the inverter (4) converts the DC power sent by the DC bus (5) into AC power and then sends it to the AC power grid through output terminals T1 and T2.

[0172] The first communication module (12) sends a measurement synchronization signal and a measurement control signal to a plurality of second communication modules (23) in the string through a wireless channel, wherein the measurement control signal includes at least one of measurement start time information, measurement number information and measurement interval information;

[0173] Furthermore, the first communication module (12) sends the bus current value measured by the bus current measurement circuit (11) included in the bus current measurement module (1) to the plurality of second communication modules (23) in the string through a wireless channel.

[0174] Furthermore, the MPPT module (21) included in the power optimizer (2) uses the bus current value received by the second communication module (23) to perform maximum power point tracking on the photovoltaic component.

[0175] The method provided in the specific implementation manner of the utility model can be implemented in whole or in part through software instructions and / or hardware circuits; the modules or units included in the device provided in the specific implementation manner of the utility model can be implemented using electronic components.

[0176] The above is only a preferred embodiment of the utility model and is not intended to limit the scope of protection of the utility model. Any technician in the field of the utility model can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed by the utility model, but the scope of protection of the utility model shall be based on the scope defined by the attached claims.

[0177] The device provided in the specific implementation of the utility model overcomes at least one of the following shortcomings of the existing photovoltaic module maximum power point tracking technology: the dual sensor optimizer using current and voltage measurement values ​​introduces an increase in measurement cost and a large measurement power consumption, the single sensor optimizer using voltage measurement values ​​is difficult to ensure the tracking point accuracy and stability of the MPPT, and the lack of data transmission capabilities of the communication channel to reduce the measurement cost and measurement power consumption of the MPPT. The MPPT current measurement power consumption and cost are reduced.

Claims

1. A maximum power point tracking device for a photovoltaic string assembly, comprising a bus current measurement circuit (11), a voltage measurement module (22), an MPPT module (21), a second communication module (23), and at least one of a third communication module (61), a first communication module (12) and a main communication module; characterized in that: A bus current measurement circuit (11), used for measuring the DC bus current at a first position of the photovoltaic string DC bus, comprising a current sensor and a signal conditioning circuit; A voltage measurement module (22) is used to measure the voltage of the photovoltaic module at the power output port position of the photovoltaic module included in the photovoltaic string, and comprises a voltage signal sampling circuit and a signal conditioning circuit; the power output port position of the photovoltaic module is a spatial position different from the first position; A second communication module (23) is located at a power output port of the photovoltaic module, and is used to receive a bus current value obtained by measuring the DC bus current at a first position of the photovoltaic string DC bus from at least one of the third communication module (61), the first communication module (12), and the main communication module, and transmit the bus current value to a corresponding maximum power point tracking unit MPPT module (21) facing the photovoltaic module, and comprises a communication receiving module using a wired channel or a wireless channel; The MPPT module (21) is a maximum power point tracking unit for a photovoltaic module, which uses a measured value of a photovoltaic module voltage at a power output port of the photovoltaic module and a measured value of a DC bus current obtained at a first position to perform maximum power point tracking on a corresponding photovoltaic module, and comprises a maximum power point determination circuit and a power point adjustment circuit.

2. The component maximum power point tracking device according to claim 1, characterized in that: The bus current measurement circuit (11) performs a DC bus current measurement operation at a first position of a DC bus of a photovoltaic string, and the voltage measurement module (22) performs a photovoltaic module voltage measurement operation at a power output port position of a photovoltaic module included in the photovoltaic string, specifically comprising: At least one of the third communication module (61), the first communication module (12) and the main communication module uses a wired or wireless channel to send a measurement synchronization signal to the second communication module (23), and in synchronization with the measurement synchronization signal, the bus current measurement circuit (11) performs DC bus current measurement at a first position of the photovoltaic string DC bus; and / or the voltage measurement module (22) performs photovoltaic module voltage measurement at a power output port position of a photovoltaic module included in the photovoltaic string; The measurement synchronization signal includes measurement trigger information or measurement start time information.

3. The component maximum power point tracking device according to claim 2, characterized in that: The operation of at least one of the third communication module (61), the first communication module (12) and the main communication module sending a measurement synchronization signal to the second communication module (23) using a wired or wireless channel specifically comprises: Using any one of the first communication module (12) and the third communication module (61) at the first position to send a measurement synchronization signal to a second communication module (23) arranged at the power output port position of the photovoltaic component through a wired or wireless channel; or A communication module on the main communication node is used to send a measurement synchronization signal to a second communication module (23) connected to the main communication node, and any one of a first communication module (12) and a third communication module (61) through a wired or wireless channel.

4. The component maximum power point tracking device according to claim 1, characterized in that: The second communication module (23) is in communication connection with at least one of the third communication module (61), the first communication module (12) and the main communication module. The second communication module (23) uses the communication connection to receive a bus current value obtained by measuring a DC bus current at a first position of a photovoltaic string DC bus, and transmits the bus current value to a corresponding maximum power point tracking unit MPPT module (21) for a photovoltaic assembly. Specifically: There is a wired channel or a wireless channel connection between the first communication module (12) or the third communication module (61) at the first position and the second communication module (23) in the power optimizer (2) located at the power output port of the photovoltaic module, and the first communication module (12) or the third communication module (61) uses the channel connection to send the measured value of the DC bus current to the MPPT module (21) in the power optimizer (2) through the second communication module (23) in a broadcast manner; or A wired channel or wireless channel connection exists between the first communication module (12) or the third communication module (61) at the first position and the communication module on the main communication node. The first communication module (12) or the third communication module (61) uses the channel connection to send the measured value of the DC bus current to the communication module on the main communication node. The communication module on the main communication node sends the received measured value of the DC bus current to the MPPT module (21) in the power optimizer (2) via the second communication module (23) in the power optimizer (2) located at the power output port of the photovoltaic module.

5. The component maximum power point tracking device according to claim 1, characterized in that: The MPPT module (21) is electrically connected to the DC / DC conversion circuit (24), and the electrical connection is used for the MPPT module (21) to adjust the output power of the DC / DC conversion circuit (24); specifically, The MPPT module (21) in the power optimizer (2) uses the photovoltaic module voltage measurement value obtained by measuring the photovoltaic module voltage at the power output port position of the photovoltaic module by the voltage measurement module (22) in the power optimizer (2), and uses the DC bus current measurement value obtained at the first position and received by the second communication module (23) to calculate the power output value of the photovoltaic module, and determines the position of the maximum power point of the photovoltaic module according to the power output values ​​at different times; The MPPT module (21) adjusts the output power of the DC / DC conversion circuit (24) through the electrical connection according to the determined position of the maximum power point of the photovoltaic assembly.

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