A combined grid-friendly photovoltaic power collection system for 5G base stations

Abstract

A kind of combined grid-friendly photovoltaic confluence system for 5G base station, including confluence unit, sensing unit, photovoltaic power generation system is accessed to direct current bus through confluence unit;Sensing unit collects distribution network voltage information and is transmitted to confluence unit in real time;Confluence unit according to distribution network voltage and direct current bus voltage, dynamically adjusts output power.Confluence unit includes: main power circuit, auxiliary power supply circuit, sampling circuit, drive circuit, control module, protection circuit, first wireless communication module.Sensing unit includes: single-chip microcomputer, wireless communication module, ac power grid power quality monitoring unit, auxiliary power supply.The utility model discloses a kind of combined grid-friendly photovoltaic confluence system for 5G base station, to be able to cope with 5G base station inside direct current bus overvoltage problem, simultaneously can according to the distribution network voltage of surrounding node, dynamically adjust power output, improve the stability of power supply system.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic power generation technology, specifically to a combined grid-friendly photovoltaic combiner system for 5G base stations. Background Technology

[0002] With the integration of large-scale distributed photovoltaic (PV) power generation systems into the distribution network, the traditional unidirectional radial network has evolved into a multi-source network, affecting power flow and voltage distribution. The high R / X ratio of low-voltage lines and the radial topology mean that the decoupling relationship between active and reactive power no longer holds, and both significantly impact voltage. Due to the inherent randomness, intermittency, and volatility of PV power generation, the mismatch between residential load characteristics and PV power generation characteristics after PV integration into the distribution network leads to significant voltage variations at various nodes in the low-voltage grid. During the daytime, if the power output from PV cannot be fully absorbed by local loads, reverse power flow will occur, causing node voltage to rise. As reverse power increases, node voltage may even exceed its upper limit, affecting normal electricity consumption for residents.

[0003] Combining photovoltaic power generation with 5G base stations, and using clean energy to power these stations, can achieve energy transformation while ensuring the stability and reliability of digital infrastructure. The power to the DC bus within a 5G base station is provided by both an AC-DC converter and a photovoltaic DC-DC converter. However, the dynamic adjustment time of the upstream AC-DC converter has a certain delay. Sudden increases in photovoltaic output or sudden drops in DC load can cause a rapid rise in the DC bus voltage. Without intervention, this can lead to overvoltage, damaging communication equipment on the DC bus and preventing the 5G base station from operating normally.

[0004] Traditional photovoltaic (PV) power generation systems commonly employ Maximum Power Point Tracking (MPPT) control technology. Its core principle is to dynamically adjust the operating point of the PV array to match the equivalent impedance of the PV cells with the external circuit impedance, thereby achieving maximum power transmission. However, this technology has significant limitations in 5G base station applications: First, when the load on a 5G base station changes abruptly, such as a sudden drop in communication traffic, the traditional MPPT algorithm still maintains maximum power output, which can easily cause the DC bus voltage to exceed the safety threshold, reaching a measured maximum of 71V, seriously threatening the safety of communication equipment. Second, existing MPPT algorithms only optimize the maximum power output of the PV array, failing to respond to the power regulation needs of the power grid dispatch and effectively suppressing the voltage exceeding limits at the distribution network end caused by the inability to absorb PV energy. Summary of the Invention

[0005] This invention makes innovative improvements to the traditional photovoltaic power generation system by introducing a combiner unit and an AC grid sensing unit to construct a combined grid-friendly photovoltaic combiner system for 5G base stations. This system can address the DC bus overvoltage problem in 5G base stations and dynamically adjust the power output according to the distribution network voltage of surrounding nodes, thereby improving the stability of the power supply system.

[0006] The technical solution adopted by this utility model is as follows:

[0007] A combined grid-friendly photovoltaic combiner system for 5G base stations includes:

[0008] The photovoltaic power generation system is connected to the DC bus through the combiner unit and the sensing unit.

[0009] The sensing unit collects voltage information from the power distribution network and transmits it to the combiner unit in real time.

[0010] The combiner unit dynamically adjusts its output power based on the distribution network voltage and the DC bus voltage. This solves the problem of DC bus overvoltage caused by load switching in 5G base stations, and also provides support to the power grid when the voltage at the end of the distribution network exceeds the limit.

[0011] The bus unit includes: a main power circuit, an auxiliary power supply circuit, a sampling circuit, a driving circuit, a control module, a protection circuit, and a first wireless communication module;

[0012] The main power circuit is connected to the sampling circuit, the drive circuit, and the control module, respectively.

[0013] The input side of the auxiliary power supply circuit is connected to the DC bus, and the output side of the auxiliary power supply circuit is connected to the main power circuit, sampling circuit, drive circuit and control module respectively, for supplying power to these circuits;

[0014] The drive circuit is connected to the control module and the main power circuit respectively.

[0015] The control module is connected to the sampling circuit, the protection circuit, and the first wireless communication module.

[0016] The sampling circuit includes: a voltage sampling circuit and a current sampling circuit;

[0017] like Figure 1 As shown, the voltage sampling circuit is connected to a differential operational amplifier via a DC bus, the differential operational amplifier is connected to a voltage follower, and the voltage follower is connected to a control module.

[0018] The current sampling circuit consists of a current sampling resistor connected to a differential operational amplifier, a differential operational amplifier connected to an active filter, and an active filter connected to a control module.

[0019] The main power circuit employs a synchronous Buck circuit topology.

[0020] The voltage sampling circuit includes a voltage divider resistor, and the current sampling circuit includes an alloy sampling resistor.

[0021] The voltage sampling circuit divides the input high voltage using voltage divider resistors; the current sampling circuit converts the current signal into a voltage signal using alloy sampling resistors. The attenuated voltage signals obtained from both are amplified by a differential operational amplifier, and finally, the filtered voltage signal is input to the control module through an active filter circuit.

[0022] The drive circuit uses a half-bridge driver chip with bootstrapping capability to achieve synchronous drive of the switching transistors of the main power circuit by the controller. The controller uses a microcontroller to control the entire system.

[0023] The protection circuit consists of over-temperature protection, over-voltage protection, over-current protection, overload protection, soft start, backflow prevention, and grid connection surge protection.

[0024] The combiner unit based on the above design connects the photovoltaic system to the DC bus side of the base station, reducing the number of photovoltaic grid-connected power conversion stages and costs, and improving the utilization efficiency of photovoltaics.

[0025] The sensing unit adopts a fully isolated scheme and includes: a microcontroller, a wireless communication module, an AC power grid power quality monitoring unit, and an auxiliary power supply;

[0026] like Figure 2 As shown, the microcontroller is connected to the second wireless communication module and the AC power grid power quality monitoring unit, respectively.

[0027] The auxiliary power supply is connected to the microcontroller, the wireless communication module, and the AC power grid power quality monitoring unit, respectively, to supply power to these modules.

[0028] like Figure 3 As shown, the AC power grid power quality monitoring unit includes a voltage transformer connected to the AC bus, a high-precision alloy resistor sampling circuit connected to the high-precision alloy resistor sampling circuit connected to the AC power grid power quality monitoring chip, a microcontroller connected to the microcontroller connected to the second wireless communication module, and the second wireless communication module communicating with the first wireless communication module in the combiner unit.

[0029] The high-voltage AC signal is reduced to a small signal by a high-precision alloy resistor sampling circuit and transmitted to the AC power grid power quality monitoring chip for signal processing. The main control chip then reads the corresponding registers to obtain the AC power grid voltage information via serial communication and finally transmits it to the combiner unit through the second wireless communication module.

[0030] The system works as follows:

[0031] When the combiner unit detects that the DC bus voltage of the 5G base station exceeds the set threshold, it adjusts the operating point of the photovoltaic array of the photovoltaic power generation system by changing the duty cycle of the combiner unit to reduce the power output, thereby effectively suppressing the DC bus overvoltage.

[0032] When the sensing unit detects that the voltage at the end of the surrounding distribution network exceeds the safety limit, it sends an adjustment command to the combiner unit through the second wireless communication module. After the combiner unit receives and interprets the command, it reduces the power output to suppress the rise of the voltage at the end of the distribution network and improve the voltage stability of the distribution network.

[0033] This utility model discloses a combined grid-friendly photovoltaic combiner system for 5G base stations, with the following technical advantages:

[0034] 1) The photovoltaic combiner system of this utility model can replace part of the power grid power consumption of the base station through direct photovoltaic DC power supply, which significantly reduces the energy consumption and electricity cost of the base station operation, while reducing carbon emissions caused by traditional energy consumption.

[0035] 2) The photovoltaic combiner system of this utility model can sense the grid voltage and DC bus voltage status in real time and dynamically adjust the photovoltaic output power system. It can dynamically adjust the output power according to the distribution network voltage and the base station DC bus voltage, thereby effectively suppressing DC bus overvoltage and providing support to the grid when the voltage at the end of the distribution network exceeds the limit. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0037] Figure 1 This is a diagram showing the current and voltage sampling structure of the bus unit of this utility model.

[0038] Figure 2 This is a structural diagram of the sensing unit of this utility model.

[0039] Figure 3 This is a schematic diagram of the communication between the sensing unit and the merging unit of this utility model.

[0040] Figure 4 This is a system structure diagram of this utility model.

[0041] Figure 5 This is a structural diagram of the busbar unit of this utility model;

[0042] Figure 6 This is a diagram showing the main power topology of the combiner unit of this utility model;

[0043] Figure 7(a) shows the auxiliary power supply principle of the combiner unit of this utility model. Figure 1 ;

[0044] Figure 7(b) shows the auxiliary power supply principle of the combiner unit of this utility model. Figure 2 .

[0045] Figure 8 This is a schematic diagram of the input voltage sampling principle of the bus unit of this utility model;

[0046] Figure 9 This is a schematic diagram of the output voltage sampling principle of the bus unit of this utility model;

[0047] Figure 10 This is a schematic diagram of the current sampling principle of the bus unit of this utility model;

[0048] Figure 11 This is a schematic diagram of the driving circuit of the bus unit of this utility model;

[0049] Figure 12 This is a schematic diagram of the main control chip of the bus unit of this utility model;

[0050] Figure 13 This is a schematic diagram of the over-temperature protection principle of the bus unit of this utility model;

[0051] Figure 14 This is a schematic diagram of the backflow protection principle of the combiner unit of this utility model;

[0052] Figure 15 This is a schematic diagram illustrating the operating principle of the sensing unit and the merging unit of this utility model.

[0053] Figure 16 This is a schematic diagram of the LoRa communication module of this utility model;

[0054] Figure 17 A flowchart illustrating the control strategy for a combined grid-friendly photovoltaic combiner system for 5G base stations.

[0055] Figure 18(a) shows the output voltage after the traditional algorithm has large output power fluctuations and the load changes.

[0056] Figure 18(b) shows the output voltage of the improved algorithm after a load change.

[0057] Figure 18(c) shows the experimental waveform of the photovoltaic cell after partial shading and subsequent removal of shading in the combiner unit using the traditional perturbation-observation MPPT algorithm;

[0058] Figure 18(d) shows the experimental waveforms of the photovoltaic cells in the bus unit after partial shading and subsequent removal of shading using the improved L-MPPT algorithm.

[0059] Figure 19 This is a diagram showing the experimental results of the AC-side distribution network in this utility model example. Detailed Implementation

[0060] The present invention will be further described below with reference to the accompanying drawings.

[0061] This utility model proposes a combined grid-friendly photovoltaic combiner system for 5G base stations, such as... Figure 4 As shown, this system consists of a combiner unit and a sensing unit. The combiner unit connects the distributed photovoltaic power generation system to the DC bus of the 5G base station. The sensing unit collects the voltage information of the surrounding distribution network and transmits it to the combiner unit in real time. The combiner unit dynamically adjusts its output power according to the voltage of the AC grid and the DC bus voltage, which solves the problem of DC bus overvoltage caused by load switching in the 5G base station. At the same time, it provides support to the grid when the voltage at the end of the distribution network exceeds the limit.

[0062] The hardware architecture of the DC combiner unit of this utility model is as follows: Figure 5 As shown, it mainly consists of the following functional circuits: main power circuit, auxiliary power supply circuit, sampling circuit, drive circuit, control module, multiple protection circuit, and first wireless communication module. The specific implementation methods of each circuit module are as follows:

[0063] like Figure 6 As shown, the main power circuit of the combiner unit can adopt a synchronous Buck topology to achieve efficient energy conversion from the DC input of the photovoltaic power generation system to the DC bus of the 5G base station.

[0064] As shown in Figures 7(a) and 7(b), the auxiliary power supply circuit can use the DC-DC step-down chip EG1192 to draw power from the DC bus of the 5G base station, convert the 53.5V voltage to 12V output, and then the 12V is output to 5V through the linear voltage regulator chip AMS1117 to provide stable voltage and power support for the sampling circuit, drive circuit and control module.

[0065] like Figure 8 As shown, the input voltage sampling can utilize a voltage divider network constructed using 150K metal film resistors with 0.1% accuracy to proportionally attenuate the photovoltaic power supply output voltage to a safe measurement range, ensuring that the sampling voltage does not exceed 3.3V and preventing overvoltage damage to the microcontroller. Simultaneously, an LM358 operational amplifier is used to construct a two-stage signal processing circuit. The first stage is a differential amplifier circuit to eliminate common-mode interference and improve measurement accuracy. The second stage is a voltage follower to achieve impedance matching and ensure stable transmission of the sampling signal.

[0066] like Figure 9As shown, the bus unit output voltage sampling uses a voltage divider network constructed with 0.1% precision metal film resistors to proportionally attenuate the 0-60V DC bus voltage to a safe measurement range. This ensures that when the bus voltage reaches its maximum value of 60V, the sampling voltage does not exceed 3.3V, preventing overvoltage damage to the microcontroller. Simultaneously, an LM358 operational amplifier is used to construct a two-stage signal processing circuit. The first stage is a differential amplifier circuit to eliminate common-mode interference and improve measurement accuracy. The second stage is a voltage follower to achieve impedance matching and ensure stable transmission of the sampling signal.

[0067] like Figure 10 As shown, the current sampling circuit of the bus unit can use an alloy sampling resistor to convert the current signal into a voltage signal. The resulting attenuated voltage signal is amplified by a differential operational amplifier, and finally the filtered voltage signal is input to the control module through an active filter circuit.

[0068] like Figure 11 As shown, the driving circuit can use the IR2110S half-bridge driver chip with bootstrap capability to realize the synchronous driving of the switching transistors of the main power circuit by the control module. The driving resistor is 10 ohms and the bootstrap capacitor is 100nF.

[0069] like Figure 12 As shown, the control module can use the domestic GigaDevice GD32 microcontroller to control the entire system. It integrates PWM generation, AD sampling, communication interface and other functional modules, and operates at a frequency of 72MHz. It can complete the calculation of all control algorithms in real time.

[0070] The protection circuit consists of over-temperature protection, over-voltage protection, over-current protection, overload protection, soft start, backflow prevention, and grid connection surge protection to ensure the safe operation of the system under various abnormal conditions.

[0071] like Figure 13 As shown, over-temperature protection can be achieved using a resistor divider circuit composed of thermistors. By monitoring the change in the thermistor's resistance, the main control chip can monitor the temperature changes of the switching devices in real time. When the temperature of the switching devices is too high, the power processed by the optimizer is controlled, thereby protecting the converter's power circuit.

[0072] like Figure 14 As shown, the backflow protection can adopt an output series MOS structure. When the output current flows in reverse, the backflow protection MOS is turned off and cannot form a loop, so the main power circuit cannot be turned on; only when the output current flows in the forward direction, the backflow protection MOS is turned on and the main power circuit is turned on.

[0073] like Figure 15As shown, the AC power quality monitoring chip for the sensing unit can use the HLW8110 chip. The auxiliary power supply powers all modules of the system. The input is connected to the AC bus via a voltage transformer, and passes through a high-precision alloy resistor sampling circuit to reduce the high-voltage AC signal to a smaller signal, which is then transmitted to the HLW8110 chip for signal processing. The main control chip then reads the corresponding registers to obtain the AC power grid voltage information via serial communication, and finally transmits it to the combiner unit via a LoRa wireless communication chip.

[0074] like Figure 16 As shown, the first and second wireless communication modules of the merging unit and sensing unit can use LoRa wireless communication chips. LoRa features long communication distance, strong anti-interference capability, low power consumption, and low latency. The communication baud rate of the distributed sensing unit and merging unit is configured as 115200, parity check 8N1, channel 12, and air rate 12.5K.

[0075] The system's workflow is as follows Figure 17 As shown,

[0076] When the surrounding AC distribution network voltage is detected U AC The bit is greater than region E and less than the upper limit of buffer IV. μ 1max DC bus voltage of base station U Bus Located in region A and less than the upper limit of buffer I η 1max At that time, the photovoltaic cells output full power. This is achieved by sampling the photovoltaic cells. U pv and I pv Calculate the output power at the current moment. P pv Calculate the change in output power Δ before and after a disturbance. P 1. Calculate the change in output power Δ after perturbing again in the same direction. P 2, Δ U This represents the change in DC bus voltage. M indicates the direction of the system disturbance: M=1 for a positive disturbance, M=0 for no change, and M=-1 for a negative disturbance. If both power changes increase, the system tracks the maximum power point of the photovoltaic cell in the forward direction; if both power changes decrease, the system tracks the maximum power point of the photovoltaic cell in the reverse direction; if the trends of the two power changes are inconsistent, the system maintains the original output power of the photovoltaic cell. As the voltage on both sides increases, the photovoltaic output power decreases step by step. λ is the output lockout state bit: λ=1 for normal output, and λ=0 for locked output.

[0077] When the surrounding AC distribution network voltage is detected UAC Bit and region F and greater than the upper limit of buffer IV μ 1max Less than the upper limit of buffer V μ 2max Collect DC bus voltage U Bus Located in region B and greater than the upper limit of buffer I η 1max Less than the upper limit of buffer II η 2max At that time, limit power output to U bus-B As U ref Using the reference voltage, a dual closed-loop power-limiting operation is implemented for both voltage and current. In this mode, the base station is powered simultaneously by photovoltaic cells and the AC grid. When the voltage of the surrounding AC distribution network... U AC Location and region H (distribution network voltage too high), DC bus voltage U Bus If the DC voltage is too high in position and region D, the light will be abandoned and the output of the λ=0 combiner unit will be blocked. At this time, the base station is fully powered by the AC distribution network, which increases the load of the distribution network and suppresses the rise of the distribution network voltage.

[0078] The experimental results of this utility model are shown in Figures 18(a) to 18(d) and Figure 19 As shown,

[0079] As shown in Figures 18(a) and 18(b), the traditional algorithm exhibits significant output power fluctuations. When the load changes, the output voltage rises from 53.5V to 71V, and this high overvoltage could damage communication equipment on the DC bus. The improved algorithm, however, controls the bus voltage from 53.5V to 55.8V after a load change, keeping it within a safe range. Furthermore, the output power decreases from 500W to 258W, effectively protecting the communication equipment on the DC bus. When the load returns to normal, the bus voltage recovers to 53.5V, and the bus unit resumes its maximum power output.

[0080] Figures 18(c) and 18(d) show the experimental waveforms of the photovoltaic cells partially shaded and then the shading was removed in the bus unit using the traditional perturbation-observation MPPT algorithm and the improved L-MPPT algorithm, respectively. U pv The output voltage of the photovoltaic cell. I pv To provide current output for photovoltaic cells, P pvThe output power is shown. It can be seen that the traditional perturbation-observation MPPT algorithm exhibits a significant transient power drop after partial shading of the photovoltaic cells. In contrast, the L-MPPT algorithm effectively suppresses the transient power drop.

[0081] Depend on Figure 19 As shown, to verify the system operating conditions under distribution network overvoltage, a sensing unit generates a distribution network overvoltage trigger signal to simulate a distribution network overvoltage. The combiner unit initially operates at full power (500W). After 6 seconds, the sensing unit generates a distribution network overvoltage signal and sends it to the combiner unit to simulate a distribution network overvoltage. Simultaneously, upon receiving the signal, the combiner unit rapidly reduces its output power. Figure 19 As can be seen, the output power of the combiner unit rapidly decreased from 500W to 350W, with a system response time of approximately 200ms. The combiner unit operated at a low power of 350W, and after 6 seconds, the sensing unit generated a trigger signal again to simulate the voltage at the end of the distribution network returning to normal. At this point, the combiner unit resumed its maximum power output of 500W, and the experimental results were consistent with expectations.

[0082] In load transition and photovoltaic cell shading experiments, the control strategy proposed in this invention can achieve maximum power point tracking. When the combiner unit detects that the DC bus voltage of the base station exceeds the set threshold, it reduces the power output by adjusting the operating point of the photovoltaic array, effectively suppressing DC bus overvoltage.

[0083] When the sensing unit detects that the voltage at the end of the surrounding distribution network exceeds the safety limit, it sends a voltage regulation command to the combiner unit through the LoRa wireless communication module. After the combiner unit receives and interprets the command, it reduces the power output to suppress the rise of the voltage at the end of the distribution network and improve the voltage stability of the distribution network.

Claims

1. A combined grid-friendly photovoltaic combiner system for 5G base stations, characterized in that... include: The photovoltaic power generation system is connected to the DC bus through the combiner unit and the sensing unit. The sensing unit collects voltage information from the power distribution network and transmits it to the combiner unit in real time. The combiner unit dynamically adjusts its output power based on the distribution network voltage and the DC bus voltage.

2. The combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 1, characterized in that: The bus unit includes: a main power circuit, an auxiliary power supply circuit, a sampling circuit, a driving circuit, a control module, a protection circuit, and a first wireless communication module; The main power circuit is connected to the sampling circuit, the drive circuit, and the control module, respectively. The input side of the auxiliary power supply circuit is connected to the DC bus, and the output side of the auxiliary power supply circuit is connected to the main power circuit, sampling circuit, drive circuit and control module respectively, for supplying power to these circuits; The drive circuit is connected to the control module and the main power circuit respectively; The control module is connected to the sampling circuit, the protection circuit, and the first wireless communication module.

3. The combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 2, characterized in that: The sampling circuit includes: a voltage sampling circuit and a current sampling circuit; The voltage sampling circuit is connected to a differential operational amplifier via a DC bus, which is then connected to a voltage follower, which in turn is connected to the control module. The current sampling circuit consists of a current sampling resistor connected to a differential operational amplifier, which in turn is connected to an active filter, which is then connected to a control module.

4. The combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 2, characterized in that: The main power circuit employs a synchronous Buck circuit topology.

5. A combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 3, characterized in that... The voltage sampling circuit includes a voltage divider resistor, and the current sampling circuit includes an alloy sampling resistor. The voltage sampling circuit divides the input high voltage using voltage divider resistors; the current sampling circuit converts the current signal into a voltage signal using alloy sampling resistors. The attenuated voltage signals obtained from both are amplified by a differential operational amplifier, and finally, the filtered voltage signal is input to the control module through an active filter circuit.

6. The combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 2, characterized in that: The driving circuit uses a half-bridge driver chip to realize the synchronous driving of the switching transistors of the main power circuit by the controller.

7. A combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 2, characterized in that: The sensing unit includes: a microcontroller, a wireless communication module, an AC power grid power quality monitoring unit, and an auxiliary power supply; The microcontroller is connected to the second wireless communication module and the AC power grid power quality monitoring unit, respectively. The auxiliary power supply is connected to the microcontroller, the wireless communication module, and the AC power grid power quality monitoring unit respectively, and supplies power to these modules. The AC power grid power quality monitoring unit includes a voltage transformer connected to the AC bus and a high-precision alloy resistor sampling circuit. The high-precision alloy resistor sampling circuit is connected to an AC power grid power quality monitoring chip, which is connected to a microcontroller. The microcontroller is connected to a second wireless communication module, which is communicatively connected to a first wireless communication module in the combiner unit.

8. A combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 7, characterized in that: The high-voltage AC signal is reduced to a small signal by a high-precision alloy resistor sampling circuit and transmitted to the AC power grid power quality monitoring chip for signal processing. The main control chip then reads the corresponding registers to obtain the AC power grid voltage information via serial communication and finally transmits it to the combiner unit through the second wireless communication module.

9. A combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 2, characterized in that: The protection circuit includes over-temperature protection, which uses a resistor voltage divider circuit composed of thermistors. By changing the resistance of the thermistors, the main control chip can monitor the temperature changes of the switching devices in real time.

10. A combined grid-friendly photovoltaic combiner system for 5G base stations according to claim 2, characterized in that: The protection circuit includes backflow protection, which adopts an output series MOS structure. When the output current flows in reverse, the backflow protection MOS is turned off and cannot form a loop, so the main power circuit cannot be turned on. Only when the output current flows in the forward direction will the backflow protection MOS be turned on and the main power circuit be turned on.

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