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

Abstract

The application discloses a kind of photovoltaic junction box based on double power energy scheduling and working method thereof, it is related to the technical field of energy management of junction box and energy management technology.The kind of photovoltaic junction box includes two independent power systems, surge protection module, DAB converter, DC ammeter and main control module.Bidirectional power transmission and energy scheduling are realized by DAB converter, when one power system generates power surplus, the excess energy is transferred to another system, to realize the maximization of photovoltaic power utilization.Main control module dynamically adjusts system operating parameters, reduces power loss, supports single or double power supply operating mode, effectively reduces the volume and number of fault points of equipment, improves system stability and energy utilization rate.It is suitable for space limited scene such as communication base station.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power distribution box and energy management, in particular to a photovoltaic power distribution box based on dual power energy scheduling and a working method thereof. BACKGROUND

[0002] The photovoltaic power distribution box is a wiring device for ensuring the orderly connection and power distribution of photovoltaic modules in a photovoltaic power generation system. The photovoltaic power distribution box functions to collect the current 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 power distribution box, through the matching use with the controller, the DC power distribution cabinet, the photovoltaic inverter and the AC power distribution cabinet, constitutes a complete photovoltaic power generation system and realizes grid connection.

[0003] For a communication base station with the characteristics of wide distribution, small space, low load and many obstructions, multiple photovoltaic modules are usually connected in series and in parallel, and then connected to a switching power supply DC output busbar through a photovoltaic power distribution box for power supply to DC loads. For a communication base station, the application of DC light superposition can reduce the input of commercial power and reduce the carbon emissions of the base station, and also facilitate the power supply design of remote sites.

[0004] Many current communication base stations have two or more power systems. However, a conventional single power distribution box can only access one power system at the same time, so multiple independent power distribution boxes are needed, which occupies a large space. Since the power distribution box is usually installed inside the power distribution room, it will affect the limited space of the power distribution room. Further, the current power distribution box design is mostly in the form of single power input or output, and cannot realize energy scheduling between different power systems, so it cannot realize optimal matching of photovoltaic power generation and loads, resulting in energy waste.

[0005] To solve the above problems, the present application provides a photovoltaic power distribution box with bidirectional DCDC conversion function, which can not only realize energy scheduling of multiple inputs and double isolated outputs, but also reduce energy loss and improve energy utilization efficiency by using zero voltage switching (ZVS) and three-phase shift control (TPS) technology. SUMMARY

[0006] To solve the problems of single power distribution box intelligent access to single power and inability to realize energy scheduling between different power systems, the present application provides a photovoltaic power distribution box based on dual power energy scheduling and a working method thereof, which can access one or two power systems. The -48V busbar after power distribution is independent and has a bidirectional DCDC conversion function, which can schedule energy according to the power generation of each photovoltaic system and the power load, so as to maximize the utilization of photovoltaic power generation.

[0007] The present application realizes the above-mentioned purposes through the following technical solutions:

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

[0009] Two mutually isolated power systems for providing independent DC power respectively, any one of the power systems can work alone or simultaneously, each photovoltaic array corresponds to a miniature circuit breaker, ensuring automatic cut-off of current in case of overload or short circuit;

[0010] Two independent surge protection modules for protecting the surge current of the two power systems respectively, preventing current surge or voltage mutation from causing damage to the system, and automatically cutting off the faulty power system through a feedback mechanism and the main control module, ensuring system safety;

[0011] A DAB converter for connecting the main bridge and the auxiliary bridge through a high-frequency transformer, supporting forward and reverse DC power transmission, having electrical isolation function, optimizing current waveform and power flow by adjusting switching frequency and duty cycle, minimizing RMS current and reducing power loss;

[0012] A dual-loop DC power meter for measuring current and voltage in the two isolated loops and transmitting to the main control module;

[0013] A main control module for controlling the working mode of the main bridge and the auxiliary bridge in the DAB converter, dynamically adjusting switching frequency, duty cycle and phase shift angle through intelligent control algorithm, optimizing power transmission direction according to changes in input voltage and load current, realizing dynamic energy scheduling between dual power systems, maximizing system efficiency and dynamic load adaptability.

[0014] As a preferred embodiment of the present application, the DAB transformer comprises:

[0015] The main bridge: a full-bridge circuit composed of Q1, Q2, Q3 and Q4, the switching tubes are connected between the positive and negative poles of one power system respectively, for realizing power conversion and converting DC power into high-frequency current;

[0016] The auxiliary bridge: a full-bridge circuit composed of Q5, Q6, Q7 and Q8, the switching tubes are connected between the positive and negative poles of the other power system respectively, for realizing power conversion and converting DC power into high-frequency current;

[0017] The high-frequency transformer: for connecting 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 with the main bridge circuit, and inductor L2 is connected with the auxiliary bridge circuit, for realizing electrical isolation and energy transmission;

[0018] Resonant circuit: including capacitor C1 in series with inductance L1 and capacitor C2 in series with inductance L2, for generating resonance, thereby optimizing power transmission and improving energy conversion efficiency of the system.

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

[0020] In the forward power transmission mode, the main bridge outputs high-frequency switching signals, which are transmitted to the auxiliary bridge through the high-frequency transformer, and the auxiliary bridge provides DC output after rectification by switching.

[0021] In the reverse power transmission mode, the auxiliary bridge outputs high-frequency switching signals, which are transmitted to the main bridge through the high-frequency transformer, and the main bridge provides DC output after rectification by switching.

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

[0023]

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

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

[0026] The zero-voltage switching technology is used to reduce switching loss, and the switching timing satisfies the following conditions:

[0027] The main bridge switching timing satisfies:

[0028]

[0029] The auxiliary bridge switching timing satisfies:

[0030]

[0031] wherein I1 is the current on the main bridge side; I2 is the current on the auxiliary 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 for realizing zero-voltage switching; δ is the phase shift 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;

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

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

[0034]

[0035] The optimized power transmission duty cycle formula is:

[0036]

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

[0038] As a preferred scheme of the application, the master module dynamically adjusts the phase offset angle δ and the duty cycles d1 and d2 between the main bridge and the auxiliary bridge by real-time collection of the changes in the input voltage, the output current and the load voltage, so as to minimize the system power loss and optimize the target to meet the following conditions:

[0039]

[0040] In the formula, P loss is the system power loss; R eq is the system equivalent resistance, I load represents the load current, and P switching represents the switching loss under the dynamically adjusted switching frequency.

[0041] The master module dynamically switches 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, the phase offset angle δ and the duty cycles d1 and d2 are reduced to reduce the switching loss.

[0043] In the heavy load mode, the phase offset angle δ is preferentially adjusted, and the power transmission direction is optimized to improve the transmission 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 ; and P threshold is a preset load power threshold.

[0046] The main control module detects the abnormal value of the phase shift angle delta, the current I1 on the main bridge side and the current I2 on the auxiliary bridge side in real time, and if the 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 delta is limited to prevent the power fluctuation from causing damage to the equipment.

[0047] As a preferred scheme of the application, the surge protection module comprises:

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

[0049] A protection triggering mechanism linked with the main control module, which feeds back the surge abnormality to the main control module when detecting that the surge voltage tolerance is out of limit.

[0050] As a preferred scheme of the application, the photovoltaic combiner box is suitable for the dual-path isolated power supply scene of a communication base station, and realizes the energy management of multiple photovoltaic inputs and dual-path load outputs.

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

[0052] Initialization: starting and detecting the state of two mutually isolated power systems, judging whether each power system is in an available state; if any power system is found to be faulty, triggering the corresponding miniature circuit breaker to cut off the faulty power supply, and isolating the faulty path through the miniature circuit breaker;

[0053] Energy input monitoring and management: real-time acquisition of the input voltage and input current of each power system, calculation of the current input power, selection of single-power supply or dual-power supply mode in combination with the input power and load demand;

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

[0055] 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 auxiliary bridge after isolation through a high-frequency transformer and provides DC output after switching rectification;

[0056] In the reverse transmission mode, the power is transmitted in the same path in the reverse direction to realize bidirectional energy flow;

[0057] Load adaptation and scheduling: according to the dynamic changes of the load current and load power, the main control module switches the light load mode and the heavy load mode in real time:

[0058] Light load mode: reducing the switching frequency and the phase shift angle to reduce the switching loss;

[0059] Heavy load mode: Optimize duty cycle and phase shift angle, maximize transmission efficiency;

[0060] Real-time safety monitoring: The main control module monitors the main bridge and auxiliary bridge current, input and output voltage, and phase shift angle in real time, and when surge current, voltage anomaly or power overrun is detected, 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 power meter continuously monitors the current, voltage and energy consumption of the two power paths and transmits real-time data to the main control module;

[0062] Run and stop: Continuously monitor and adjust during operation, and 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.

[0063] The beneficial effects of the present application are: through the mutual isolation design of the dual-path photovoltaic system, high safety is realized, two power systems work independently, even if one system fails, it will not affect the normal operation of the other system, improve the reliability and fault tolerance of the system as a whole; Through the DAB converter, energy scheduling between different power systems is realized, when the power of one photovoltaic power generation exceeds the load demand of the power system, the DAB converter will intervene and transfer the excess energy to another power system, through supporting forward power transmission and reverse power transmission two working modes, the DAB converter dynamically optimizes the energy distribution, makes the power of photovoltaic power generation maximized utilization, 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, in the case of limited application scene, especially suitable for communication base stations or other limited space scenes with high requirements for equipment volume; In addition, due to the reduction of the number of components, the number of potential failure points is also reduced, further reducing the risk of system failure, ensuring higher stability and reliability of the system during operation, adapting to complex operating environment and prolonging the service life of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0064] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0065] Among them:

[0066] Figure 1This is a general structural diagram of the photovoltaic combiner box in an embodiment of the present invention;

[0067] Figure 2 This is a circuit diagram of the DAB converter in an embodiment of the present invention. Detailed Implementation

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

[0069] like Figure 1 As shown, this is an embodiment of the present invention, which provides a photovoltaic combiner box based on dual-power supply energy dispatch, suitable for dual-isolated power supply scenarios of communication base stations, realizing energy management of multiple photovoltaic inputs and dual-load outputs, including:

[0070] Two isolated power supply systems Figure 1 The power system is referred to as power system 1 and power system 2, which are used to provide independent DC power. Each power system can work alone or simultaneously. It is compatible with most base station power supplies on the market. Each photovoltaic array corresponds to a miniature circuit breaker to ensure that the current is automatically cut off in case of overload or short circuit.

[0071] Two independent surge protection modules ( Figure 1 The surge protection module (referred to as surge protection module 1 and surge protection module 2) is used to protect the surge current of the two power systems respectively, preventing current surges or voltage surges from damaging the system. It also links with the main control module through a feedback mechanism to automatically disconnect the power system that has failed, ensuring system safety. The surge protection module includes: a surge absorption circuit that can absorb instantaneous surge current in the input circuit; and a protection triggering mechanism that links with the main control module to report a surge abnormality to the main control module when the surge voltage withstand limit is detected to be exceeded.

[0072] A DAB converter connects the main and secondary bridges via a high-frequency transformer, supporting forward and reverse DC power transfer. It features electrical isolation and optimizes current waveform and power flow by adjusting the switching frequency and duty cycle, minimizing RMS current and reducing power loss. The basic structure of a DAB converter includes two H-bridge circuits located on the primary and secondary sides of the high-frequency transformer, respectively. Each H-bridge consists of four switching transistors used to control the direction and amount of power transfer. Inductor windings are connected in series with the high-frequency transformer; these windings act as the primary energy storage element, helping to smooth current and improve efficiency.

[0073] The direct current meter, preferably a dual-loop direct current meter, is used to measure the current and voltage in two isolated loops and transmit to the master control module; a set of metering and control equipment is used to realize the access and exit of different power supply systems, which helps to reduce the product size and cost;

[0074] The master control module is used to control the working mode of the main bridge and the auxiliary bridge in the DAB converter, dynamically adjusts the switching frequency, duty cycle and phase shift angle through intelligent control algorithm, optimizes the power transmission direction according to the change of input voltage and load current, realizes the dynamic energy scheduling between dual power supply systems, maximizes the system efficiency and dynamic load adaptability.

[0075] The master control module has uplink and downlink communication functions (not limited to specific ways, such as 4G, Lora for uplink, Bluetooth, wifi, carrier wave, etc. for downlink).

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

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

[0078] The main bridge: a full-bridge circuit composed of Q1, Q2, Q3 and Q4, the switching tubes are connected between the positive and negative poles of one power supply system, respectively, for realizing power conversion and converting direct current into high-frequency current;

[0079] The auxiliary bridge: a full-bridge circuit composed of Q5, Q6, Q7 and Q8, the switching tubes are connected between the positive and negative poles of another power supply system, respectively, for realizing power conversion and converting direct current into high-frequency current;

[0080] The resonance circuit: including capacitor C1 in series with inductor L1 and capacitor C2 in series with inductor L2, for generating resonance to optimize power transmission and improve the energy conversion efficiency of the system;

[0081] The high-frequency transformer: used to connect the main bridge circuit and the auxiliary bridge circuit, the high-frequency transformer T has inductor L1 and inductor L2 connected in series on both sides, inductor L1 is connected with the main bridge circuit, and inductor L2 is connected with the auxiliary bridge circuit, for realizing electrical isolation and energy transmission.

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

[0083]

[0084] Wherein, L1 is the self-inductance of the inductor L1, used to store the primary side energy and transfer the energy to the secondary side through high-frequency magnetic field. Its value is determined by the number of turns and the core material; L m is the magnetizing inductance of the high-frequency transformer, representing the inductance characteristics of the transformer core itself, used to establish the magnetic field and maintain the balance of magnetic flux; the stability condition shows that the transformer design needs to ensure the advantage of the primary winding self-inductance over the magnetizing inductance, which helps to reduce the distortion of the current waveform, and ensures 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 transmission; if Close to May cause distortion of the primary side current waveform, reduce transmission efficiency, and even cause system oscillation.

[0086] Further, the forward and reverse power transmission functions of the DAB converter include:

[0087] In the forward power transmission mode (power 1 transmits energy to power 2), the main bridge outputs high-frequency switching signals, which are transmitted to the auxiliary bridge through the high-frequency transformer, and the auxiliary bridge provides DC output after rectification by switching;

[0088] In the reverse power transmission mode (power 2 transmits energy to power 1), the auxiliary bridge outputs high-frequency switching signals, which are transmitted to the main bridge through the high-frequency transformer, and the main bridge provides DC output after rectification by switching.

[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 loss, the switching timing meets the following conditions:

[0091] The main bridge switching timing meets:

[0092]

[0093] The auxiliary bridge switching timing meets:

[0094]

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

[0096] The current I1 on the primary side of the bridge is determined by the power supply voltage, the load current, and the design of the resonant circuit. The primary bridge switching sequence condition is used to ensure that the primary bridge switch tube has sufficient current when switching, so that the parasitic capacitance on the device can be quickly charged and discharged, achieving ZVS function. The current I1 on the secondary side of the bridge is directly related to the size of the load. When the load is light, the current on the secondary side of the bridge may be too small to meet the I min requirement, and needs to be optimized by adjusting α2 or designing reasonable parameters of the secondary inductor (L2) and the capacitor (C2).

[0097] By adjusting the duty cycles (d1, d2) and the phase shift angle δ of the primary bridge and the secondary bridge, direct-current energy transmission is achieved.

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

[0099]

[0100] The optimized power transmission duty cycle formula is:

[0101]

[0102] In the formula, d1 is the duty cycle of the primary bridge; d2 is the duty cycle of the secondary bridge; d3 is the initial phase shift, preset by the master module; k is a dynamic adjustment coefficient, used to adjust the phase shift angle according to the voltage difference to optimize the power transmission efficiency; ΔV = V in -V load represents the difference between the input voltage V in and the load voltage V load ; S q1The fundamental amplitude of the DC signal output by the main bridge is the main component of the actual output signal of the main bridge for energy transmission. q2 The fundamental amplitude of the DC signal output by the auxiliary bridge reflects the effective signal part of the auxiliary bridge in power transmission.

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

[0104]

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

[0108] In the heavy load mode, the phase shift angle δ is adjusted first to optimize the power transmission direction and 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 a preset load power threshold.

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

[0112] Another embodiment of the present application also provides a working method of a photovoltaic combiner box based on dual power energy scheduling, applied to the photovoltaic combiner box based on dual power energy scheduling as described above, and comprising the following steps:

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

[0114] Energy input monitoring and management: real-time collection of input voltage and input current of each power system, calculation of current input power, selection of single power supply or dual power supply mode in combination with input power and load demand;

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

[0116] 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 auxiliary bridge after isolation through a high-frequency transformer and provides DC output after switching rectification;

[0117] In the reverse transmission mode, power is transmitted in the same path in the reverse direction to realize bidirectional energy flow;

[0118] 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:

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

[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 auxiliary bridge current, input and output voltage, and phase shift angle in real time, and when detecting surge current, voltage anomaly or power overrun, actively triggers the surge protection module to cut off the fault path and records the fault information;

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

[0123] Operation and stop: continuously monitor and adjust during operation, and 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.

[0124] In summary, the photovoltaic junction box of the present application adopts a dual-path independent power supply system structure design, realizing the mutual isolation of the two photovoltaic systems and 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 the independent surge protection module, each power supply system can be individually protected from overvoltage, effectively absorbing and suppressing transient surge current and voltage fluctuations, further ensuring the safety of system operation.

[0125] Through the bidirectional power transmission function of the DAB converter, the present application realizes energy scheduling between the two power supply systems. When the power generation of one power supply system exceeds its load demand, the DAB converter will automatically transfer the excess power to the other power supply system, supporting forward and reverse power transmission modes, so that the photovoltaic power generation power is maximized. This design improves the energy utilization rate of the photovoltaic power generation system and avoids energy waste due to excess power generation.

[0126] The present application integrates the control of the dual-path power supply system into a master control module, dynamically adjusts the switching frequency, duty cycle and phase shift angle of the DAB converter through intelligent control algorithm, optimizes the power transmission direction, and adapts to the dynamic changes of load demand. This design not only reduces the number of internal components, but also realizes efficient management and dynamic energy scheduling of the dual-path power supply system, thereby significantly reducing the overall volume and weight of the junction box and saving space. This compact design is particularly suitable for communication base stations and other space-limited application scenarios.

[0127] In addition, by reducing the number of system components, the present application reduces the complexity and number of potential failure points of the system, thereby significantly reducing the risk of equipment failure and improving the stability and service life of the system. Combined with dynamic energy scheduling and fault isolation protection functions, the photovoltaic junction box exhibits excellent reliability and adaptability in high-load and complex operating environments.

[0128] In summary, the photovoltaic junction box of the present application exhibits significant technical effects in improving operation safety, energy utilization rate, system compactness and reducing failure risk, providing a reliable solution for efficient operation of photovoltaic power generation systems and being suitable for wide application in various scenarios.

[0129] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A photovoltaic combiner box based on dual power energy scheduling, characterized in that, The photovoltaic combiner box comprises: Two mutually isolated power supply systems for providing independent direct current power respectively, any one of the power supply systems can work independently or simultaneously, each photovoltaic array corresponds to a miniature circuit breaker, which ensures automatic cut-off of current in case of overload or short circuit; Two independent surge protection modules for protecting surge current of the two power supply systems respectively, preventing current surge or voltage mutation from damaging the system, and automatically cutting off the faulty power supply system through a feedback mechanism and the main control module to ensure system safety; The DAB converter is used to connect the main bridge and the auxiliary 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 the power loss; the high-frequency transformer meets the following stability conditions: ; wherein L1 is the self-induction of the inductance L1, L m is the magnetizing inductance of the high-frequency transformer; A double-circuit direct current energy meter for measuring current and voltage in the two isolated circuits and transmitting to the main control module; The main control module is used for controlling the working mode of the main bridge and the auxiliary bridge in the DAB converter, dynamically adjusting the switching frequency, duty cycle and phase shift angle through intelligent control algorithm, optimizing the power transmission direction according to the changes of input voltage and load current, realizing dynamic energy scheduling between the two power supply systems, maximizing system efficiency and dynamic load adaptability; The intelligent control algorithm of the main control module specifically adopts a three-phase shift control algorithm, which comprises: The zero-voltage switching technology is used to reduce switching loss, and the switching timing meets the following conditions: The main bridge switch timing satisfies: ; The sub-bridge switch timing satisfies: ; wherein, is the current on the primary side; is the current on the secondary side; is the angular frequency of the high frequency DC signal; t is the time variable; is the minimum current value to achieve zero voltage switching; is the phase shift angle between the primary and secondary sides; a1 and a2 are the duty cycle shift of the primary and secondary sides, respectively; By adjusting the duty cycle (d1, d2) and phase shift angle δ of the main bridge and the auxiliary bridge, direct current energy transmission is realized; The calculation formula of the phase shift angle δ is: ; The optimized power transfer duty cycle formula is: ; ; In the formula, d1 is the duty ratio of the main bridge; d2 is the duty ratio of the auxiliary bridge; d3 is an initial phase offset, which is preset by the main control module; is a dynamic adjustment coefficient; represents the difference between the input voltage and the load voltage ; is the fundamental amplitude of the output DC signal of the main bridge; is the fundamental amplitude of the output DC signal of the auxiliary bridge; The main control module dynamically adjusts the phase shift angle δ and the duty cycle d1, d2 between the main bridge and the auxiliary bridge by real-time acquisition of the changes of input voltage, output current and load voltage, so as to realize the minimization of system power loss and optimize the target to meet the following conditions: ； wherein is the system power loss; is the system equivalent resistance, denotes the load current, denotes the switching loss at a dynamically adjusted switching frequency; The main control module dynamically switches between light load mode and heavy load mode according to the real-time load condition of the system: In the light load mode, the phase shift angle δ and the duty cycle d1, d2 are reduced to reduce switching loss; In the heavy load mode, the phase shift angle δ is adjusted first to optimize the power transmission direction and improve transmission efficiency; The mode switching condition is based on the load power Dynamic range of the load power Light load mode: ; heavy load mode: ; is a preset load power threshold value; The main control module monitors the phase offset angle φ and the current on the main bridge side in real time. and the current on the secondary bridge side If abnormal values ​​are detected, such as system overload or short circuit risk, the duty cycle d1 and d2 will be automatically reduced, and the maximum value of the phase offset angle φ will be limited to prevent power fluctuations from damaging the equipment.

2. The photovoltaic combiner box based on dual power energy scheduling according to claim 1, characterized in that, The DAB converter comprises: The main bridge: a full-bridge circuit composed of Q1, Q2, Q3 and Q4, the switching tubes are connected between the positive and negative poles of one power supply system respectively, for realizing power conversion and converting direct current energy into high-frequency current; The auxiliary bridge: a full-bridge circuit composed of Q5, Q6, Q7 and Q8, the switching tubes are connected between the positive and negative poles of the other power supply system respectively, for realizing power conversion and converting direct current energy into high-frequency current; The high-frequency transformer: for connecting the main bridge circuit and the auxiliary bridge circuit, the two sides of the high-frequency transformer T are respectively connected with inductance L1 and inductance L2 in series, inductance L1 is connected with the main bridge circuit, and inductance L2 is connected with the auxiliary bridge circuit, for realizing electrical isolation and energy transmission; The resonance circuit: including capacitor C1 connected with inductance L1 in series and capacitor C2 connected with inductance L2 in series, for generating resonance to optimize power transmission and improve energy conversion efficiency of the system.

3. The photovoltaic combiner box based on dual power energy scheduling according to claim 2, characterized in that, The forward and reverse power transmission functions of the DAB converter comprise: In the forward power transmission mode, the main bridge outputs high-frequency switching signal, which is transmitted to the auxiliary bridge through the high-frequency transformer, and the auxiliary bridge provides direct current output after switching rectification; In the reverse power transmission mode, the auxiliary bridge outputs high-frequency switching signals, which are transmitted to the main bridge through the high-frequency transformer, and the main bridge provides DC output after rectification by switching.

4. The photovoltaic combiner box based on dual power energy scheduling according to claim 1, characterized in that, The surge protection module comprises: A surge absorption circuit capable of absorbing transient surge current in the input circuit; A protection triggering mechanism linked to the main control module, which feeds back surge abnormalities to the main control module when detecting surge voltage tolerance over-limit.

5. The photovoltaic combiner box based on dual power energy scheduling according to claim 1, characterized in that, The photovoltaic combiner box is suitable for the double-path isolated power supply scene of a communication base station, and realizes energy management of multiple photovoltaic inputs and double-path load outputs.

6. A working method of a photovoltaic combiner based on dual power energy scheduling, applied to a photovoltaic combiner based on dual power energy scheduling according to any one of claims 1-5, characterized in that, It comprises: Initialization: Start and detect the status of two mutually isolated power supply systems, and determine whether each power supply system is in an available state; If any power supply system is found to be faulty, trigger the corresponding miniature circuit breaker to cut off the faulty power supply, and isolate the fault path through the miniature circuit breaker; Energy input monitoring and management: Real-time collection of input voltage and input current of each power supply system, calculation of current input power, selection of single power supply or double power supply mode in combination with input power and load demand; Energy transmission control: Adjust the switching frequency, duty cycle and phase shift angle between the main bridge and the auxiliary bridge of the DAB converter through 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 high-frequency switching signals, which are transmitted to the auxiliary bridge after isolation by the high-frequency transformer and rectified by switching to provide DC output; In the reverse transmission mode, power is transmitted in the same path in the reverse direction to realize 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 loss; Heavy load mode: Optimize 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 current, input and output voltage, and phase shift angle in real time, actively triggers the surge protection module to cut off the fault path when detecting surge current, voltage abnormalities or power over-limit, and records fault information; Energy metering and feedback: The dual-loop DC power meter continuously monitors the current, voltage and energy consumption of the two power paths, and transmits real-time data to the main control module; Operation and stop: Continuously monitor and adjust during operation, and enter standby mode when the load is disconnected or the input power is insufficient; When the system detects that the input power is restored or the load is reconnected, it automatically resumes normal operation.

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