Photovoltaic combiner box based on dual power supply energy scheduling and working method thereof

Abstract

The invention discloses a photovoltaic combiner box based on dual power supply energy scheduling and a working method thereof, and relates to the technical field of combiner boxes and energy management. The photovoltaic combiner box comprises two independent power supply systems, a surge protection module, a DAB converter, a DC ammeter and a master control module. Bidirectional power transmission and energy scheduling are realized through the DAB converter, and when the generated power of one power supply system is excessive, excess energy is transferred to the other system, so that the maximum utilization of photovoltaic power is realized. The master control module dynamically adjusts system operation parameters, reduces power loss, supports a single-path or double-path power supply working mode, effectively reduces the equipment size and the number of fault points, and improves the system stability and the energy utilization rate. The method is suitable for space-limited scenes such as communication base stations.

Description

Technical Field

[0001] The present invention relates to the technical fields of busbar boxes and energy management, and particularly relates to a photovoltaic busbar box based on dual-power energy scheduling and a working method thereof. Background Art

[0002] A photovoltaic busbar box is a wiring device that ensures the orderly connection and busbar function of photovoltaic modules in a photovoltaic power generation system. The function of the photovoltaic busbar box is to collect the currents from different photovoltaic modules together, reduce the number of cables between the photovoltaic array and the inverter, thereby simplifying the wiring and reducing the installation cost. The output of the photovoltaic busbar box is used in combination with a controller, a DC power distribution cabinet, a photovoltaic inverter, and an AC power distribution cabinet to form a complete photovoltaic power generation system and achieve grid connection.

[0003] For communication base stations with the characteristics of wide distribution, small space, low load, and many obstacles, multiple photovoltaic module strings are usually connected in series and parallel and then converge through a photovoltaic busbar box to access the DC output busbar of the switching power supply to supply power to DC loads. For communication base stations, the application of DC superposition of light can reduce the mains input on the one hand and reduce the carbon emissions of the base station on the other hand, and is also convenient for the power supply design of remote sites.

[0004] Currently, many communication base stations have two or more power systems. However, a conventional single busbar box can only access 1 power system at the same time, so multiple independent busbar boxes are required, which takes up a large amount of space. Since the busbar box is usually installed inside the power distribution room, it will affect the limited space of the power distribution room; further, the current busbar box design is mostly in the form of single-channel power input or output, and it is impossible to achieve energy scheduling between different power systems, nor can the optimal matching between photovoltaic power generation and loads be achieved, resulting in energy waste.

[0005] In view of the above problems, the present invention proposes a photovoltaic busbar box with a bidirectional DCDC conversion function, which can not only achieve energy scheduling of multiple inputs and dual isolated outputs, but also reduce energy loss and improve energy utilization efficiency by adopting zero-voltage switching (ZVS) and three-phase shift control (TPS) technologies. Summary of the Invention

[0006] In view of problems such as a single busbar box only being able to intelligently access a single power source and being unable to achieve energy scheduling between different power systems, the present invention proposes a photovoltaic busbar box based on dual-power energy scheduling and a working method thereof, which can access one or two power systems. The -48V busbar after busbar connection is independent and has a bidirectional DCDC change function, and can perform energy scheduling according to the power generation situation of each photovoltaic system and the power load, so as to maximize the utilization of photovoltaic power generation.

[0007] The present invention achieves the above object through the following technical solutions:

[0008] A photovoltaic combiner box based on dual power supply energy scheduling, the photovoltaic combiner box comprising:

[0009] Two isolated power supply systems are used to provide independent DC power supplies. Any of the power supply systems can work alone or simultaneously. Each photovoltaic array corresponds to a miniature circuit breaker to ensure automatic current cutoff in case of overload or short circuit.

[0010] Two independent surge protection modules are used to protect the surge current of the two power systems respectively, preventing current surge or voltage mutation from damaging the system. They are linked with the main control module through the feedback mechanism to automatically cut off the faulty power system to ensure system safety.

[0011] DAB converter, used to connect the main bridge and the auxiliary bridge through a high-frequency transformer, supports forward and reverse DC power transmission, has electrical isolation function, optimizes current waveform and power flow by adjusting switching frequency and duty cycle, minimizes effective current and reduces power loss;

[0012] Dual-circuit DC energy meter, used to measure the current and voltage in two isolated circuits and transmit them to the main control module;

[0013] The main control module is used to control the working mode of the main bridge and the auxiliary bridge in the DAB converter. It dynamically adjusts the switching frequency, duty cycle and phase shift angle through intelligent control algorithms, optimizes the power transmission direction according to the changes in input voltage and load current, and realizes dynamic energy scheduling between dual power supply systems, maximization of system efficiency and dynamic load adaptability.

[0014] As a preferred solution of the present invention, the DAB transformer comprises:

[0015] Main bridge: A full-bridge circuit consisting of four switch tubes Q1, Q2, Q3, and Q4, which are respectively connected between the positive and negative poles of a power system to achieve power conversion and convert DC power into high-frequency current;

[0016] Auxiliary bridge: A full-bridge circuit consisting of four switch tubes Q5, Q6, Q7, and Q8, which are respectively connected between the positive and negative poles of another power supply system to achieve power conversion and convert DC power into high-frequency current;

[0017] High-frequency transformer: used to connect the main bridge circuit and the auxiliary bridge circuit. The two sides of the high-frequency transformer T are respectively connected in series with inductor L1 and inductor L2. Inductor L1 is connected to the main bridge circuit, and inductor L2 is connected to the auxiliary bridge circuit to achieve electrical isolation and energy transfer.

[0018] Resonant circuit: It includes a capacitor C1 connected in series with an inductor L1 and a capacitor C2 connected in series with an inductor L2, which is used to generate resonance, thereby optimizing power transmission and improving the energy conversion efficiency of the system.

[0019] As a preferred embodiment of the present invention, the forward and reverse power transmission functions of the DAB converter include:

[0020] In the forward power transmission mode, the main bridge outputs a high-frequency switching signal, which is transmitted to the secondary bridge through the high-frequency transformer. The secondary bridge provides a DC output after switching rectification;

[0021] In the reverse power transmission mode, the secondary bridge outputs a high-frequency switching signal, which is transmitted to the main bridge through the high-frequency transformer. The main bridge provides a DC output after switching rectification.

[0022] As a preferred embodiment of the present invention, the high-frequency transformer satisfies the following stability conditions:

[0023]

[0024] Wherein, L1 is the self-inductance of the inductor L1, and L m is the magnetizing inductance of the high-frequency transformer.

[0025] As a preferred embodiment of the present invention, the intelligent control algorithm of the main control module specifically adopts a three-phase shift control algorithm, including:

[0026] Using zero-voltage switching technology to reduce switching losses, and the switching timing satisfies the following conditions:

[0027] The switching timing of the main bridge satisfies:

[0028]

[0029] The switching timing of the secondary bridge satisfies:

[0030]

[0031] In the formula, I1 is the current on the main bridge side; I2 is the current on the secondary bridge side; ω is the angular frequency of the high-frequency DC signal; t is the time variable; I min is the minimum current value to achieve zero-voltage switching; δ is the phase shift angle between the main bridge and the secondary bridge; α1 and α2 are the duty cycle offset amounts of the main bridge and the secondary bridge respectively;

[0032] By adjusting the duty cycles (d1, d2) and the phase shift angle δ of the main bridge and the secondary bridge, DC energy transmission is achieved;

[0033] The calculation formula for the phase shift angle δ is:

[0034]

[0035] The optimized power transfer duty cycle formula is as follows:

[0036]

[0037] Where d1 is the duty cycle of the main bridge; d2 is the duty cycle of the auxiliary bridge; d3 is the initial phase offset, preset by the main control module; k is the dynamic adjustment coefficient; △V = V in - V load represents the input voltage V in and the difference between the load voltage V load ; S q1 is the fundamental amplitude of the DC signal output by the main bridge; S q2 is the fundamental amplitude of the DC signal output by the auxiliary bridge.

[0038] As a preferred solution of the present invention, the main control module dynamically adjusts the phase offset angle δ and the duty cycles d1, d2 between the main bridge and the auxiliary bridge by real-time collecting the changes of the input voltage, output current and load voltage, so as to minimize the system power loss, and the optimization target satisfies the following conditions:

[0039]

[0040] Where P loss is the system power loss; R eq is the system equivalent resistance, I load represents the load current, P switching represents the switching loss at the dynamically adjusted switching frequency;

[0041] The main control module dynamically switches between the light load mode and the heavy load mode according to the real-time load conditions of the system:

[0042] In the light load mode, reduce the phase offset angle δ and the duty cycles d1, d2 to reduce the switching loss;

[0043] In the heavy load mode, preferentially adjust the phase offset angle δ to optimize the power transfer direction to improve the transfer efficiency;

[0044] The mode switching condition is based on the dynamic range of the load power P load :

[0045] Light load mode: P load < P threshold ; Heavy load mode: P load ≥ P threshold ; P threshold is the preset load power threshold;

[0046] The main control module continuously detects the abnormal values of the phase shift angle δ, the current I1 on the main bridge side, and the current I2 on the secondary bridge side. If system overload or short - circuit risks are detected, it automatically reduces the duty cycles d1 and d2 and limits the maximum value of the phase shift angle δ to prevent damage to the equipment caused by power fluctuations.

[0047] As a preferred embodiment of the present invention, the surge protection module includes:

[0048] A surge absorption circuit capable of absorbing instantaneous surge current in the input loop;

[0049] A protection trigger mechanism linked to the main control module, which feeds back surge abnormalities to the main control module when the detected surge voltage tolerance limit is exceeded.

[0050] As a preferred embodiment of the present invention, the photovoltaic busbar box is applicable to the dual - path isolated power supply scenario of communication base stations, realizing energy management for multiple photovoltaic inputs and dual - path load outputs.

[0051] A working method of a photovoltaic busbar box based on dual - power energy scheduling, applied to a photovoltaic busbar box based on dual - power energy scheduling as described above, includes:

[0052] Initialization: Start and detect the states of two mutually isolated power supply systems, and determine whether each power supply system is in an available state; if a fault is found in any power supply system, trigger the corresponding miniature circuit breaker to cut off the faulty power supply and isolate the faulty path through the miniature circuit breaker;

[0053] Energy input monitoring and management: Continuously collect the input voltage and input current of each power supply system, calculate the current input power, and select a single - path power supply or dual - path power supply mode in combination with the input power and load demand;

[0054] Energy transmission control: Adjust the switching frequency, duty cycle, and phase shift angle between the main bridge and the secondary bridge of the DAB converter through a three - phase shift control algorithm to control the power transmission direction;

[0055] In the forward transmission mode, convert the DC input on the main bridge side into a high - frequency switching signal, transmit it through the high - frequency transformer isolation to the secondary bridge, and provide a DC output after switching rectification;

[0056] In the reverse transmission mode, transmit power in the reverse direction through the same path to achieve bidirectional energy flow;

[0057] Load adaptation and scheduling: According to the dynamic changes of the load current and load power, the main control module continuously switches between the light - load mode and the heavy - load mode:

[0058] Light - load mode: Reduce the switching frequency and phase shift angle to reduce switching losses;

[0059] Overload Mode: Optimize the duty cycle and phase shift angle to maximize the transmission efficiency;

[0060] Real-time Safety Monitoring: The main control module monitors the currents of the main bridge and the auxiliary bridge, the input and output voltages, and the phase shift angle in real time. When surge current, abnormal voltage, or power overload is detected, it actively triggers the surge protection module to cut off the fault path and records the fault information;

[0061] Energy Metering and Feedback: The dual-loop DC energy meter continuously monitors the currents, voltages, and energy consumption of the two paths of power, and transmits the real-time data to the main control module;

[0062] Operation and Stop: Continuously monitor and adjust during operation. When the load is disconnected or the input power is insufficient, the main control module enters the standby mode; when the system detects the recovery of the input power or the reconnection of the load, it automatically resumes normal operation.

[0063] The beneficial effects of the present invention are as follows: Through the mutual isolation design of the dual-channel photovoltaic system, high safety is achieved. The two power supply systems work independently. Even if one system fails, it will not affect the normal operation of the other system, improving the overall reliability and fault resistance of the system; Through the DAB converter, energy scheduling between different power supply systems is realized. When the power of one path of photovoltaic power generation exceeds the load demand of the power supply system of this path, the DAB converter will intervene and transfer the excess energy to the power supply system of the other path. By supporting two working modes of forward power transmission and reverse power transmission, the DAB converter dynamically optimizes the energy distribution, maximizes the utilization of the power of photovoltaic power generation, and greatly improves the energy utilization rate; Through a main control module, the control of the two independent systems inside is realized, effectively reducing the number of components, optimizing the system layout, reducing the overall volume of the busbar box, saving space, and especially suitable for communication base stations or other limited space scenarios with high requirements for equipment volume in the case of limited application scenarios; In addition, due to the reduction of the number of components, the number of potential fault points is also reduced, further reducing the fault risk of the system, ensuring higher stability and reliability of the system during operation, adapting to complex operating environments and extending the service life of the equipment. Description of the Drawings

[0064] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0065] Among them:

[0066] Figure 1This is the overall structure diagram of the photovoltaic busbar box in the embodiment of the present invention;

[0067] Figure 2 This is the circuit schematic diagram of the DAB converter in the embodiment of the present invention. Specific embodiments

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0069] As Figure 1 shown, this is an embodiment of the present invention. This embodiment provides a photovoltaic busbar box based on dual - power energy scheduling, which is applicable to the dual - path isolated power supply scenario of communication base stations and realizes the energy management of multiple photovoltaic inputs and dual - path load outputs. It includes:

[0070] Two mutually isolated power systems ( Figure 1 denoted as power system 1 and power system 2 in ), which are used to provide independent DC power sources respectively. Any one of the power systems can work alone or simultaneously, and can be compatible with most base - station power sources on the market. Each photovoltaic array corresponds to a miniature circuit breaker to ensure automatic current cut - off in case of overload or short - circuit;

[0071] Two independent surge protection modules ( Figure 1 denoted as surge protection module 1 and surge protection module 2 in ), which are used to protect the surge current of the two power systems respectively, prevent current surges or voltage mutations from damaging the system, and are linked with the main control module through a feedback mechanism to automatically cut off the faulty power system to ensure system safety; The surge protection module includes: a surge absorption circuit, which can absorb the instantaneous surge current in the input loop; and a protection trigger mechanism linked with the main control module, which feeds back surge abnormalities to the main control module when the detected surge voltage tolerance limit is exceeded;

[0072] A DAB converter, which is used to connect the main bridge and the secondary bridge through a high - frequency transformer, supports forward and reverse DC power transmission, has an electrical isolation function, optimizes the current waveform and power flow by adjusting the switching frequency and duty cycle, minimizes the effective - value current, and reduces power loss; The basic structure of the DAB converter includes two H - bridge circuits located on the primary side and the secondary side of the high - frequency transformer respectively. Each H - bridge consists of four switching tubes, which are used to control the transmission direction and quantity of electric energy. The high - frequency transformer measures series inductance windings respectively, and the inductance windings, as the main energy - storage elements, help to smooth the current and improve the efficiency;

[0073] A DC ammeter, preferably a dual-loop DC energy meter, is used to measure the current and voltage in two isolated loops and transmit them to the main control module. Using a set of metering and control equipment to achieve the access and disconnection of different power systems helps to reduce the product size and cost.

[0074] The main control module is used to control the working modes of the main bridge and the secondary bridge in the DAB converter, dynamically adjust the switching frequency, duty cycle and phase shift angle through intelligent control algorithms, optimize the power transmission direction according to the changes of the input voltage and load current, and achieve dynamic energy scheduling between the dual-power systems, maximization of system efficiency and dynamic load adaptability.

[0075] The main control module has up and down communication functions (the specific method is not limited, for example, 4G, Lora for the uplink and Bluetooth, wifi, carrier for the downlink).

[0076] In this embodiment, the components of the photovoltaic busbar box work together to ensure the safety and efficiency of the system, and can dynamically adjust the energy distribution of the dual-power system and optimize the power flow.

[0077] As Figure 2 shown, in a specific embodiment, the DAB transformer includes:

[0078] The main bridge: a full-bridge circuit composed of four switching tubes Q1, Q2, Q3, and Q4. The switching tubes are respectively connected between the positive and negative poles of a power system and are used to achieve power conversion and convert DC electrical energy into high-frequency current.

[0079] The secondary bridge: a full-bridge circuit composed of four switching tubes Q5, Q6, Q7, and Q8. The switching tubes are respectively connected between the positive and negative poles of another power system and are used to achieve power conversion and convert DC electrical energy into high-frequency current.

[0080] The resonant circuit: includes a capacitor C1 in series with an inductor L1 and a capacitor C2 in series with an inductor L2, and is used to generate resonance, thereby optimizing power transmission and improving the energy conversion efficiency of the system.

[0081] The high-frequency transformer: is used to connect the main bridge circuit and the secondary bridge circuit. Inductors L1 and L2 are respectively connected in series on both sides of the high-frequency transformer T. Inductor L1 is connected to the main bridge circuit, and inductor L2 is connected to the secondary bridge circuit, and is used to achieve electrical isolation and energy transfer.

[0082] The high-frequency transformer meets the following stability conditions:

[0083]

[0084] Among them, L1 is the self-inductance of inductor L1, which is used to store the primary-side energy and transfer the energy to the secondary side through the high-frequency magnetic field. Its value is determined by the number of winding turns and the magnetic core material; L m is the magnetizing inductance of the high-frequency transformer, representing the inductance characteristic of the transformer magnetic core itself, which is used to establish the magnetic field and maintain the balance of magnetic flux; this stability condition indicates that the transformer design needs to ensure the superiority of the primary winding self-inductance relative to the magnetizing inductance, which helps to reduce the distortion of the current waveform and ensure the stability and effectiveness of energy transmission;

[0085] Formula indicates that the self-inductance of the primary winding must be significantly greater than the magnetizing inductance to ensure the stability of energy transfer; if is close to it may cause distortion of the primary-side current waveform, reduce the transmission efficiency, and even cause system oscillation.

[0086] Furthermore, the forward and reverse power transfer functions of the DAB converter include:

[0087] In the forward power transfer mode (power supply 1 transfers energy to power supply 2), the main bridge outputs a high-frequency switching signal, which is transmitted to the secondary bridge through the high-frequency transformer, and the secondary bridge provides a DC output after switching rectification;

[0088] In the reverse power transfer mode (power supply 2 transfers energy to power supply 1), the secondary bridge outputs a high-frequency switching signal, which is transmitted to the main bridge through the high-frequency transformer, and the main bridge provides a DC output after switching rectification.

[0089] In one embodiment, the intelligent control algorithm of the main control module specifically adopts a three-phase shift control algorithm, including:

[0090] Using zero-voltage switching technology to reduce switching losses, and the switching timing satisfies the following conditions:

[0091] The main bridge switching timing satisfies:

[0092]

[0093] The secondary bridge switching timing satisfies:

[0094]

[0095] Wherein, I1 is the current on the main - bridge side, which is used to drive the current in the primary winding (inductor L1) of the high - frequency transformer of the main bridge. Its magnitude determines whether zero - voltage switching can be achieved through the parasitic capacitance of the charge - discharge switching tube; I2 is the current on the secondary - bridge side, which is used to drive the current in the secondary winding (inductor L2) of the high - frequency transformer of the secondary bridge. Its magnitude also determines whether zero - voltage switching can be achieved on the secondary bridge; ω is the angular frequency of the high - frequency DC signal, with the unit of radians per second (rad / s), which is determined by the operating frequency of the DAB converter; t is the time variable; I min is the minimum current value for achieving zero - voltage switching (ZVS), which is used to quickly charge and discharge the parasitic capacitance of the switching tube to ensure the conditions for zero - voltage switching; δ is the phase - shift angle between the main bridge and the secondary bridge, which controls the direction and magnitude of the energy transfer between the main bridge and the secondary bridge. A positive shift indicates that the main bridge transfers energy to the secondary bridge, and a negative shift indicates that the secondary bridge transfers energy to the main bridge; α1 and α2 are the duty - cycle offsets of the main bridge and the secondary bridge respectively, which control the on - off time of the switching tubes and indirectly affect the magnitude and waveform of the current;

[0096] The current I1 on the main - bridge side is determined by the power - supply voltage, load current, and the design of the resonant circuit. The main - bridge switching - timing conditions are used to ensure that the main - bridge switching tubes have sufficient current during switching, so as to quickly charge and discharge the parasitic capacitance on the devices and achieve the ZVS function. The current I1 on the secondary - bridge side is directly related to the load size. When the load is light, the current on the secondary - bridge side may be too small to meet the I min requirement, and it needs to be optimized by adjusting α2 or designing reasonable parameters of the secondary inductor (L2) and capacitor (C2).

[0097] DC energy transfer is achieved by adjusting the duty cycles (d1, d2) and phase - shift angle δ of the main bridge and the secondary bridge;

[0098] The calculation formula for the phase - shift angle δ is:

[0099]

[0100] The optimized power - transfer duty - cycle formula is:

[0101]

[0102] Wherein, d1 is the duty cycle of the main bridge; d2 is the duty cycle of the secondary bridge; d3 is the initial phase - shift amount, which is preset by the main control module; k is the dynamic adjustment coefficient, which is used to adjust the phase - shift angle according to the voltage difference to optimize the power - transfer efficiency; △V = V in -V load represents the difference between the input voltage V in and the load voltage V load ; S q1is the fundamental amplitude of the DC signal output by the main bridge, which is the main component for energy transmission in the actual output signal of the main bridge; S q2 is the fundamental amplitude of the DC signal output by the auxiliary bridge, reflecting the effective signal part of the auxiliary bridge in power transmission.

[0103] Specifically, the main control module dynamically adjusts the phase offset angle δ and duty cycles d1, d2 between the main bridge and the auxiliary bridge by real-time collecting the changes of the input voltage, output current and load voltage, so as to minimize the system power loss, and the optimization target satisfies the following conditions:

[0104]

[0105] In the formula, P loss is the system power loss. In order to improve the efficiency of the photovoltaic busbar box, the main control module needs to dynamically adjust the control parameters (such as the phase offset angle δ, duty cycles d1, d2, etc.) to minimize P loss P loss ; R eq is the system equivalent resistance, representing the sum of the resistance components (such as winding resistance) in the main bridge, auxiliary bridge and high-frequency transformer and the resistance in other paths; I load represents the load current, referring to the magnitude of the current output by the system to the load; P switching represents the switching loss at the dynamically adjusted switching frequency;

[0106] The main control module dynamically switches between the light load mode and the heavy load mode according to the real-time load conditions of the system:

[0107] In the light load mode, reduce the phase offset angle δ and duty cycles d1, d2 to reduce the switching loss;

[0108] In the heavy load mode, preferentially adjust the phase offset angle δ to optimize the power transmission direction to improve the transmission efficiency;

[0109] The mode switching condition is based on the dynamic range of the load power P load :

[0110] Light load mode: P load < P threshold ; Heavy load mode: P load ≥ P threshold ; P threshold is the preset load power threshold;

[0111] The main control module real-time detects the abnormal values of the phase offset angle δ, the current I1 on the main bridge side and the current I2 on the auxiliary bridge side. If the system overload or short-circuit risk is detected, it automatically reduces the duty cycles d1 and d2 and limits the maximum value of the phase offset angle δ to prevent power fluctuations from damaging the equipment.

[0112] Another embodiment of the present invention further provides a working method for a photovoltaic busbar box based on dual - power energy scheduling, which is applied to a photovoltaic busbar box based on dual - power energy scheduling as described above, and includes the following steps:

[0113] Initialization: Start and detect the states of two isolated power systems, and determine whether each power system is in an available state; if any power system failure is found, trigger the corresponding miniature circuit breaker to cut off the faulty power supply, and isolate the faulty path through the miniature circuit breaker;

[0114] Energy input monitoring and management: Real - time collect the input voltage and input current of each power system, calculate the current input power, and select a single - path power supply or a dual - path power supply mode in combination with the input power and load demand;

[0115] Energy transfer control: Adjust the switching frequency, duty cycle, and phase - shift angle between the main bridge and the secondary bridge of the DAB converter through a three - phase shift control algorithm to control the power transfer direction;

[0116] In the forward transfer mode, convert the DC input on the main - bridge side into a high - frequency switching signal, isolate it through a high - frequency transformer, transfer it to the secondary bridge, and provide a DC output after switching rectification;

[0117] In the reverse transfer mode, transfer power in the reverse direction through the same path to achieve bidirectional energy flow;

[0118] Load adaptation and scheduling: According to the dynamic changes of the load current and load power, the main control module switches between the light - load mode and the heavy - load mode in real time:

[0119] Light - load mode: Reduce the switching frequency and phase - shift angle to reduce switching losses;

[0120] Heavy - load mode: Optimize the duty cycle and phase - shift angle to maximize the transmission efficiency;

[0121] Real - time safety monitoring: The main control module monitors the main - bridge and secondary - bridge currents, input and output voltages, and phase - shift angle in real time. When a surge current, abnormal voltage, or power limit is detected, actively trigger the surge protection module to cut off the faulty path and record the fault information;

[0122] Energy metering and feedback: The dual - loop DC energy meter continuously monitors the current, voltage, and energy consumption of the two - path power, and transmits the real - time data to the main control module;

[0123] Operation and stop: Continuously monitor and adjust during operation. When the load is disconnected or the input power is insufficient, the main control module enters the standby mode; when the system detects the recovery of the input power or the re - connection of the load, it automatically resumes normal operation.

[0124] In summary, the photovoltaic busbar box of the present invention adopts a dual - path independent power supply system structure design, achieving the mutual isolation of two photovoltaic systems, effectively avoiding mutual interference between different power supply systems during operation. Even if one power supply system fails, it will not affect the normal operation of the other power supply system, greatly improving the operation safety and reliability of the system. In addition, through an independent surge protection module, over - voltage protection can be carried out separately for each power supply system, effectively absorbing and suppressing instantaneous surge current and voltage fluctuations, further ensuring the operation safety of the system.

[0125] Through the bidirectional power transfer function of the DAB converter, the present invention realizes the energy scheduling between two power supply systems. When the power generation power of one power supply system exceeds its load demand, the DAB converter will automatically transfer the excess electric energy to another power supply system, supporting forward and reverse power transfer working modes, maximizing the utilization of photovoltaic power generation. This design improves the energy utilization rate of the photovoltaic power generation system and avoids energy waste caused by over - generation.

[0126] The present invention integrates the control of the dual - path power supply system into a main control module, dynamically adjusts the switching frequency, duty cycle and phase - shift angle of the DAB converter through intelligent control algorithms, optimizes the power transfer direction, and adapts to the dynamic changes of load demand. This design not only reduces the number of components inside the system, but also realizes the efficient management and dynamic energy scheduling of the dual - path power supply system, thus significantly reducing the overall volume and weight of the busbar box and saving space. This compact design is especially suitable for application scenarios with limited space such as communication base stations.

[0127] In addition, by reducing the number of system components, the present invention reduces the system complexity and the number of potential failure points, thus significantly reducing the failure risk of the equipment and improving the system stability and service life. Combining the dynamic energy scheduling and fault isolation protection functions, the photovoltaic busbar box shows excellent reliability and adaptability under high - load and complex operating environments.

[0128] In summary, the photovoltaic busbar box of the present invention shows significant technical effects in improving operation safety, energy utilization rate, system compactness and reducing failure risk, provides a reliable solution for the efficient operation of the photovoltaic power generation system, and is suitable for a wide range of applications in various scenarios.

[0129] The above - mentioned is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of various changes or substitutions, and these should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A photovoltaic combiner box based on dual power supply energy scheduling, characterized in that: The photovoltaic combiner box comprises: Two isolated power supply systems are used to provide independent DC power supplies. Any of the power supply systems can work alone or simultaneously. Each photovoltaic array corresponds to a miniature circuit breaker to ensure automatic current cutoff in case of overload or short circuit. Two independent surge protection modules are used to protect the surge current of the two power systems respectively, preventing current surge or voltage mutation from damaging the system. They are linked with the main control module through the feedback mechanism to automatically cut off the faulty power system to ensure system safety. DAB converter, used to connect the main bridge and the auxiliary bridge through a high-frequency transformer, supports forward and reverse DC power transmission, has electrical isolation function, optimizes current waveform and power flow by adjusting switching frequency and duty cycle, minimizes effective current and reduces power loss; Dual-circuit DC energy meter, used to measure the current and voltage in two isolated circuits and transmit them to the main control module; The main control module is used to control the working mode of the main bridge and the auxiliary bridge in the DAB converter. It dynamically adjusts the switching frequency, duty cycle and phase shift angle through intelligent control algorithms, optimizes the power transmission direction according to the changes in input voltage and load current, and realizes dynamic energy scheduling between dual power supply systems, maximization of system efficiency and dynamic load adaptability.

2. A photovoltaic combiner box based on dual power supply energy scheduling according to claim 1, characterized in that: The DAB transformer comprises: Main bridge: A full-bridge circuit consisting of four switch tubes Q1, Q2, Q3, and Q4, which are respectively connected between the positive and negative poles of a power system to achieve power conversion and convert DC power into high-frequency current; Auxiliary bridge: A full-bridge circuit consisting of four switch tubes Q5, Q6, Q7, and Q8, which are respectively connected between the positive and negative poles of another power supply system to achieve power conversion and convert DC power into high-frequency current; High-frequency transformer: used to connect the main bridge circuit and the auxiliary bridge circuit. Inductor L1 and inductor L2 are connected in series on both sides of the high-frequency transformer T respectively. Inductor L1 is connected to the main bridge circuit, and inductor L2 is connected to the auxiliary bridge circuit, which is used to achieve electrical isolation and energy transfer; resonant circuit: includes capacitor C1 connected in series with inductor L1 and capacitor C2 connected in series with inductor L2, which is used to generate resonance, thereby optimizing power transmission and improving the energy conversion efficiency of the system.

3. A photovoltaic combiner box based on dual power supply energy scheduling according to claim 2, characterized in that: The forward and reverse power transfer functions of the DAB converter include: In the forward power transmission mode, the main bridge outputs a high-frequency switching signal, which is transmitted to the auxiliary bridge through a high-frequency transformer. The auxiliary bridge provides a DC output after switch rectification. In the reverse power transmission mode, the secondary bridge outputs a high-frequency switching signal, which is transmitted to the main bridge through a high-frequency transformer. The main bridge provides a DC output after switch rectification.

4. A photovoltaic combiner box based on dual power supply energy scheduling according to claim 3, characterized in that: The high frequency transformer meets the following stability conditions: Where, L1 is the self-inductance of inductor L1, L m is the magnetizing inductance of the high-frequency transformer.

5. A photovoltaic combiner box based on dual power supply energy scheduling according to claim 1, characterized in that: The intelligent control algorithm of the main control module specifically adopts a three-phase shift control algorithm, including: Use zero voltage switching technology to reduce switching losses, and the switching timing meets the following conditions: The main bridge switch timing meets: The secondary bridge switch timing meets: Where, I1 is the current on the main bridge side; I2 is the current on the secondary bridge side; ω is the angular frequency of the high-frequency DC signal; t is the time variable; I min is the minimum current value to achieve zero voltage switching; δ is the phase offset angle between the main bridge and the auxiliary bridge; α1 and α2 are the duty cycle offsets of the main bridge and the auxiliary bridge respectively; By adjusting the duty ratio (d1, d2) and phase shift angle δ of the main bridge and the auxiliary bridge, DC energy transmission is achieved; The calculation formula of the phase shift angle δ is: The optimized power transfer duty cycle formula is: Where d1 is the duty cycle of the main bridge; d2 is the duty cycle of the secondary bridge; d3 is the initial phase offset, which is preset by the main control module; k is the dynamic adjustment coefficient; △V = V in -V load Indicates the input voltage V in With load voltage V load The difference between q1 S is the fundamental amplitude of the DC signal output by the main bridge; q2 It is the fundamental amplitude of the DC signal output by the secondary bridge.

6. A photovoltaic combiner box based on dual power supply energy scheduling according to claim 5, characterized in that: The main control module collects the changes of input voltage, output current and load voltage in real time, and dynamically adjusts the phase offset angle δ and duty ratios d1 and d2 between the main bridge and the auxiliary bridge to minimize the system power loss. The optimization target meets the following conditions: Where P loss is the system power loss; R eq is the system equivalent resistance, I load Indicates the load current, P switching Indicates the switching loss under dynamic adjustment of switching frequency; The main control module dynamically switches between light load mode and heavy load mode according to the real-time load conditions of the system: In light load mode, the phase shift angle δ and duty cycle d1, d2 are reduced to reduce switching losses. In heavy load mode, the phase shift angle δ is adjusted first to optimize the power transmission direction to improve the transmission efficiency; Mode switching conditions are based on load power P load Dynamic range: Light load mode: P load <P threshold ; Heavy load mode: P load ≥P threshold ;P threshold is a preset load power threshold; The main control module detects abnormal values ​​of the phase shift angle δ, the current I1 on the main bridge side, and the current I2 on the secondary bridge side in real time. If a system overload or short circuit risk is detected, the duty cycles d1 and d2 are automatically reduced and the maximum value of the phase shift angle δ is limited to prevent power fluctuations from damaging the equipment.

7. A photovoltaic combiner box based on dual power supply energy scheduling according to claim 1, characterized in that: The surge protection module comprises: Surge absorption circuit, which can absorb instantaneous surge current in the input circuit; The protection trigger mechanism linked with the main control module feeds back surge abnormality to the main control module when it detects that the surge voltage tolerance exceeds the limit.

8. A photovoltaic combiner box based on dual power supply energy scheduling according to claim 1, characterized in that: The photovoltaic combiner box is suitable for a dual-path isolated power supply scenario of a communication base station, and realizes energy management of multi-path photovoltaic input and dual-path load output.

9. A working method of a photovoltaic combiner box based on dual power supply energy scheduling, applied to a photovoltaic combiner box based on dual power supply energy scheduling as claimed in any one of claims 1 to 8, characterized in that: include: Initialization: Start and detect the status of two isolated power systems to determine whether each power system is in an available state; If any power supply system fails, the corresponding miniature circuit breaker will be triggered to cut off the faulty power supply, and the faulty path will be isolated through the miniature circuit breaker; Energy input monitoring and management: collect the input voltage and input current of each power system in real time, calculate the current input power, and select single-channel or dual-channel power supply mode based on the input power and load requirements; Energy transmission control: The switching frequency, duty cycle and phase shift angle between the main bridge and the auxiliary bridge of the DAB converter are adjusted through the three-phase shift control algorithm to control the power transmission direction; In the forward transmission mode, the DC input on the main bridge side is converted into a high-frequency switching signal, which is transmitted to the secondary bridge after isolation by a high-frequency transformer and provided as a DC output after switch rectification; In reverse transmission mode, power is transferred in the opposite direction through the same path, achieving bidirectional energy flow; Load adaptation and scheduling: According to the dynamic changes of load current and load power, the main control module switches between light load mode and heavy load mode in real time: Light load mode: reduce switching frequency and phase shift angle to reduce switching losses; Heavy load mode: optimizes duty cycle and phase shift angle to maximize transmission efficiency; Real-time safety monitoring: The main control module monitors the main bridge and auxiliary bridge currents, input and output voltages, and phase deviation angles in real time. When surge current, voltage abnormalities, or power over-limit are detected, the surge protection module is actively triggered to cut off the fault path and record the fault information. Energy measurement and feedback: The dual-circuit DC energy meter continuously monitors the current, voltage and energy consumption of the two power lines and transmits real-time data to the main control module; Run and stop: Continuously monitor and adjust during operation. When the load is disconnected or the input power is insufficient, the main control module enters standby mode; when the system detects that the input power is restored or the load is reconnected, it automatically resumes normal operation.

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