An AC-DC hybrid charging system based on power adaptive control

Abstract

The utility model discloses a kind of AC-DC hybrid charging system based on power self-adaptive control, including front-stage energy input module, unified power control module and battery load.Front-stage energy input module contains at least one AC / DC circuit and a photovoltaic DC / DC circuit, output end is connected to form common bus in parallel;The DC / DC-3 circuit of unified power control module connects common bus and battery, controls charging current based on the voltage droop characteristic of Vs, and current-limiting power reduction when battery reaches full power threshold value.Photovoltaic DC / DC circuit uses MPPT control when VsV1, Vs>V1 when high threshold current-limiting;AC / DC circuit control bus voltage automatically supplements power, output current is less than I1 or Vs>V2 when zero power output.The system does not need branch communication, realizes self-adaptive cooperation by voltage droop characteristic, simplifies structure, reduces cost, improves energy utilization efficiency and reliability, supports multiple energy expansion and protects battery.

Description

Technical Field

[0001] This utility model relates to the field of new energy charging, specifically to an AC / DC hybrid charging system based on power adaptive control. Background Technology

[0002] With the development of new energy technologies, hybrid charging systems combining mains power and photovoltaics are widely used in various battery charging scenarios because they can fully utilize renewable energy and reduce dependence on the power grid. In existing technologies, mains charging branches and photovoltaic charging branches are usually connected in parallel, and each branch is equipped with an independent front-end conversion circuit and a rear-end battery-side DC / DC circuit. The charging current of the corresponding branch is adjusted by the rear-end circuit.

[0003] Because of the maximum charging current limit of the battery, each branch needs to exchange information in real time through the communication module and rely on a complex scheduling strategy to allocate the charging current to avoid current overload or power conflict. For example, when the photovoltaic power fluctuates, the output power of the mains branch needs to be adjusted through the scheduling algorithm to supplement it; when the number of branches increases, the scheduling logic needs to be redesigned to adapt to the coordination of multiple branches, resulting in an exponential increase in system control complexity.

[0004] Furthermore, configuring each branch with an independent downstream DC / DC circuit not only increases the number of controlled circuits and raises hardware costs, but also reduces system reliability due to the need for additional synchronization and protection mechanisms for multi-module control. Meanwhile, maximizing photovoltaic power utilization in existing systems relies on real-time communication and dynamic scheduling between branches. When communication is delayed or fails, power distribution imbalances can easily occur, leading to reduced photovoltaic utilization or fluctuations in grid-supplied power.

[0005] Therefore, in order to solve the problems existing in the prior art, this utility model proposes an AC / DC hybrid charging system based on power adaptive control. Utility Model Content

[0006] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an AC / DC hybrid charging system based on power adaptive control.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A hybrid AC / DC charging system based on power adaptive control includes a front-end energy input module, a unified power control module, and a battery load; The front-end energy input module includes at least one AC / DC circuit and at least one photovoltaic DC / DC circuit. The output terminals of each circuit are connected in parallel to form a common bus, and the bus voltage of the common bus is Vs. The unified power control module includes a DC / DC-3 circuit, whose input is connected to the common bus and whose output is connected to the battery load. The DC / DC-3 circuit is configured to uniformly control the battery charging current based on the voltage droop characteristic of the bus voltage Vs. When the bus voltage Vs decreases, the charging current is reduced; when the bus voltage Vs increases, the charging current is maintained or increased; and when the battery load voltage reaches a preset full charge threshold, the current is limited and the charging power is reduced.

[0008] As a further improvement of this utility model, the photovoltaic DC / DC circuit is configured such that when the bus voltage Vs is less than a preset first threshold V1, the photovoltaic panel output power is controlled using the MPPT algorithm; when the bus voltage Vs is greater than the preset first threshold V1, the output voltage high threshold current limiting control is used.

[0009] As a further improvement of this utility model, the AC / DC circuit is configured such that when the output current is greater than the current threshold I1, output voltage droop control is used to supplement the power gap of the photovoltaic DC / DC circuit; when the circuit output current is less than the current threshold I1 or the bus voltage is greater than the second threshold V2, burst operation mode is used.

[0010] As a further improvement of this utility model, the AC / DC circuit is a totem pole power factor correction circuit, including an inductor, at least four switching transistors and a freewheeling diode; one end of the inductor is connected to the mains input, and the other end is connected to a bridge rectifier unit composed of switching transistors, which has a structure to realize mains rectification and voltage boost by controlling the switching transistors to turn on and off, and outputs a stable DC voltage to the common bus.

[0011] As a further improvement of this utility model, the photovoltaic DC / DC circuit is a Boost circuit, including an inductor, a switching transistor, a diode, and a capacitor, which has a structure that realizes the output voltage boost and power control of the photovoltaic panel by adjusting the duty cycle of the switching transistor; in single photovoltaic charging mode and when the battery charging power exceeds the maximum power of the photovoltaic panel, the bus voltage Vs decreases as the power demand increases, and the DC / DC-3 circuit automatically reduces the charging current based on the voltage droop characteristic.

[0012] As a further improvement of this utility model, the DC / DC-3 circuit is a Buck circuit, including an inductor, a switching transistor, a diode, and a capacitor. It has a structure that adjusts the output current by controlling the on-time of the switching transistor through a closed loop to achieve precise control of the charging current. Its preset voltage-current droop curve is configured as follows: when the bus voltage Vs is the reference voltage V0, the rated charging current is output; when Vs decreases by a preset voltage difference ΔV, the output current decreases by a fixed proportion; its response time is configured to not exceed 10ms to adapt to rapid matching of photovoltaic or mains power fluctuations.

[0013] As a further improvement of this utility model, the current limiting control structure of the DC / DC-3 circuit when the battery load voltage reaches the full charge threshold is configured such that the output voltage limiting ring automatically limits the charging current.

[0014] As a further improvement of this utility model, the MPPT algorithm of the photovoltaic DC / DC circuit adjusts the operating point by detecting the direction of change in output power before and after the disturbance; when the power increases with the voltage, the voltage continues to increase; when the power decreases with the voltage, the voltage is reduced until it stabilizes at the maximum power point.

[0015] As a further improvement of this utility model, the voltage droop control configuration is such that the output voltage is based on a second threshold V2 and decreases linearly with the increase of the output current, wherein the second threshold is lower than the first threshold; the burst operation mode is such that when the output current is less than the current threshold I1 or the bus voltage is greater than the second threshold V2, it operates in standby mode, and when the output voltage is lower than the third threshold V3, it resumes operation; wherein the third threshold V3 is lower than the second threshold V2.

[0016] The beneficial effects of this utility model are: (1) Simplify the system structure, reduce the number of controlled circuits and communication modules, and reduce hardware costs.

[0017] (2) No complex scheduling strategy and branch communication are required. Adaptive coordination is achieved through voltage droop characteristics, which improves control reliability.

[0018] (3) When photovoltaic power is insufficient, it can be efficiently tracked; when it is sufficient, it can automatically limit current; and the mains power can be smoothly supplemented as needed, thereby improving energy utilization efficiency.

[0019] (4) It supports flexible expansion of multiple energy branches and can provide refined protection for the battery, extending its service life. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an AC / DC hybrid charging system based on power adaptive control according to this utility model; Figure 2 This is a topology diagram of a totem pole power factor correction circuit for an AC / DC hybrid charging system based on power adaptive control, according to this utility model. Figure 3 This is a DC / DC circuit topology diagram of an AC / DC hybrid charging system based on power adaptive control according to this utility model; Figure 4 This is a non-isolated DC / DC circuit topology diagram of an embodiment of this utility model. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Identical components are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom surface," "top surface," "inner," and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0022] This utility model proposes an AC / DC hybrid charging system based on power adaptive control, such as... Figures 1 to 4 As shown, it includes: A hybrid AC / DC charging system based on power adaptive control includes a front-end energy input module, a unified power control module, and a battery load; The front-end energy input module includes at least one AC / DC circuit and at least one photovoltaic DC / DC circuit. The output terminals of each circuit are connected in parallel to form a common bus, and the bus voltage of the common bus is Vs. The front-end energy input module, serving as the energy access point, includes at least one AC / DC circuit for mains power input and at least one photovoltaic DC / DC circuit for photovoltaic panel input. The AC / DC circuit converts AC mains power into DC power, while the photovoltaic DC / DC circuit converts and regulates the DC power output from the photovoltaic panel. The outputs of the two circuits are connected in parallel to form a common bus. The voltage of this common bus is defined as the bus voltage Vs, which serves as the core feedback signal for the system's adaptive power control.

[0023] The unified power control module includes a DC / DC-3 circuit, whose input is connected to the common bus and whose output is connected to the battery load. The DC / DC-3 circuit is configured to uniformly control the battery charging current based on the voltage droop characteristic of the bus voltage Vs. When the bus voltage Vs decreases, the charging current is reduced; when the bus voltage Vs increases, the charging current is maintained or increased; and when the battery load voltage reaches a preset full charge threshold, the current is limited and the charging power is reduced.

[0024] The unified power control module is the core control unit of the system, containing only one DC / DC-3 circuit. Its input is connected to the common bus of the preceding energy input module, and its output is directly connected to the battery load, responsible for uniformly regulating the charging current flowing to the battery. The core control logic of the DC / DC-3 circuit is based on the voltage droop characteristic of the bus voltage Vs: when the common bus voltage Vs decreases, it indicates that the preceding input power may be insufficient. In this case, the DC / DC-3 circuit automatically reduces the output charging current to avoid overloading the preceding power. When Vs increases, it indicates that the preceding input power is sufficient. In this case, the DC / DC-3 circuit maintains the current charging current or moderately increases the current to fully utilize the preceding power. Furthermore, when the battery load voltage reaches the preset full-charge threshold, the DC / DC-3 circuit triggers a current limiting mechanism, with the output voltage limiting loop adaptively reducing the charging power to prevent battery overcharging.

[0025] The battery load serves as the energy storage end of the system and can include various types of rechargeable batteries. It receives a stable charging current through a unified power control module to complete energy storage.

[0026] Specifically, such as Figures 1 to 4 As shown, the photovoltaic DC / DC circuit is configured such that when the bus voltage Vs is less than a preset first threshold V1, the photovoltaic panel output power is controlled using the MPPT algorithm; when the bus voltage Vs is greater than the preset first threshold V1, the output voltage high threshold current limiting control is used.

[0027] Based on the above scheme, this utility model further optimizes the control logic of the photovoltaic DC / DC circuit, enabling it to adaptively switch the working mode according to the change of the common bus voltage Vs, thereby maximizing the utilization of photovoltaic power and achieving stable output.

[0028] As the core conversion unit of photovoltaic energy in the front-end energy input module, the photovoltaic DC / DC circuit's core configuration lies in its ability to autonomously adjust its output characteristics without communicating with other circuits by dividing the operating range according to a preset voltage threshold, the first threshold V1. When the voltage Vs of the common bus is less than the preset first threshold V1, it indicates that the photovoltaic output power may be insufficient and photovoltaic energy should be used first. The photovoltaic DC / DC circuit starts the maximum power point tracking algorithm, namely the MPPT algorithm, which adjusts the working voltage and current of the photovoltaic panel in real time to make the photovoltaic panel always work at the maximum power point and maximize the output power to meet the charging demand. When the voltage Vs of the common bus is greater than the preset first threshold V1, it indicates that the photovoltaic output power is sufficient or even excessive, which may lead to the bus voltage being too high. The photovoltaic DC / DC circuit switches to the high threshold current limiting control of the output voltage. By limiting its own output current or power, it avoids excessive photovoltaic power injection into the common bus and prevents abnormal Vs from affecting the system stability. Specifically, such as Figures 1 to 4 As shown, the AC / DC circuit is configured such that when the output current is greater than the current threshold I1, output voltage droop control is used to supplement the power gap of the photovoltaic DC / DC circuit; when the circuit output current is less than the current threshold I1 or the bus voltage is greater than the second threshold V2, burst operation mode is used.

[0029] Based on the above scheme, this utility model further optimizes the control strategy of the AC / DC circuit, enabling it to adaptively supplement the photovoltaic power gap or shut down according to the changes in the common bus voltage Vs or its own output current, thereby achieving seamless coordination of multiple energy sources.

[0030] As the core conversion unit for AC power input, the AC / DC circuit's control logic is configured as follows: When photovoltaic power is insufficient, the photovoltaic DC / DC circuit controls the input power, while the AC / DC circuit controls the output voltage, i.e., the bus voltage Vs. The power shortfall will be automatically filled by the AC / DC circuit, meaning current flows out of the AC / DC circuit. The AC / DC circuit implements voltage droop control based on its output current, meaning the bus voltage Vs decreases linearly with the output current. When multiple AC / DC circuits exist, this droop control enables automatic current sharing among the different AC / DC circuits.

[0031] When photovoltaic power is sufficient, the AC / DC circuit output current will be less than the current threshold I1, automatically entering burst mode. This reduces power loss while reducing power output, avoiding conflicts between mains power and photovoltaic energy, and prioritizing energy utilization. When photovoltaic power is insufficient due to fluctuations, the bus voltage Vs decreases. When it drops below the third threshold V3, the AC / DC circuit will resume operation, automatically replenishing the power and stabilizing the charging current.

[0032] The first threshold V1, the second threshold V2, the third threshold V3, the reference voltage V0, and the current threshold I1 are consistent with the above, such as V1=420V, V2=400V, V3=380V, V0=350V, and I1=1A, to ensure the unified coordination control logic among the circuits.

[0033] When the photovoltaic power is sufficient, the bus voltage Vs will be pushed up to above V2 by the additional power until it reaches V1. The photovoltaic DC / DC circuit enters high threshold current limiting control and adjusts the power to match the charging power. Because the bus voltage Vs is higher than V2, the AC / DC circuit enters burst mode and then runs in standby mode.

[0034] When photovoltaic power is insufficient, the bus voltage Vs will drop below V3 due to the lack of power. The AC / DC circuit will then resume operation, controlling the bus voltage Vs according to the voltage droop curve to maintain charging power. For example, if the AC / DC output current is 5A, the bus voltage will be controlled to 400V - 5A * 1Ω = 395V. If there is no mains power supply, the bus voltage will further drop below V0, and the DC-DC-3 circuit will reduce the charging power based on the difference between the bus voltage and the reference voltage. If the photovoltaic power is 1000W and the charging power is 2000W, the charging power decreases by 500V for every 1V decrease in bus voltage. Therefore, when the bus voltage drops to 348V, a balance between photovoltaic power and charging power is achieved.

[0035] When the photovoltaic power recovers and gradually increases, the output current of the AC / DC circuit gradually decreases until it is less than the circuit threshold I1. The AC / DC circuit then enters burst mode to reduce its own power consumption.

[0036] With the above control strategy, the AC / DC circuit does not need to communicate with the photovoltaic DC / DC circuit. It can automatically adjust and improve the system's adaptability and stability simply by monitoring the bus voltage Vs.

[0037] Specifically, such as Figures 1 to 4 As shown, the AC / DC circuit is a totem pole power factor correction circuit, including an inductor, at least four switching transistors and a freewheeling diode; one end of the inductor is connected to the mains input, and the other end is connected to a bridge rectifier unit composed of switching transistors, which has a structure to realize mains rectification and voltage boost by controlling the switching transistors to turn on and off, and outputs a stable DC voltage to the common bus.

[0038] Based on the above scheme, this utility model further specifies that the AC / DC circuit adopts a totem pole PFC topology and optimizes its control strategy in different charging modes to achieve efficient rectification and multi-energy synergy.

[0039] The totem-pole power factor correction circuit, also known as the totem-pole PFC circuit, serves as an AC / DC conversion unit. Its specific structure and control configuration are as follows: The circuit structure includes an energy storage inductor, four high-frequency switching transistors (typically MOSFETs or IGBTs), and a freewheeling diode, forming a bridge rectifier topology. The inductor input is connected to the AC mains power, and the output is connected to the midpoint of the switching transistor bridge arm. Its control logic is as follows: by controlling the conduction sequence of the switching transistors, it realizes the rectification and boosting functions of AC to DC, adjusts the PF value at the input terminal, and maintains the stability of the output voltage; furthermore, it changes the output voltage according to the magnitude of the output current to achieve voltage droop control; simultaneously, when the output current is small, it enters burst mode to reduce power consumption. In addition, when there are multiple AC / DC circuits in the system, the output voltage droop control method can realize automatic current sharing among different AC / DC circuits.

[0040] Specifically, such as Figures 1 to 4 As shown, the photovoltaic DC / DC circuit is a Boost circuit, including an inductor, a switching transistor, a diode, and a capacitor. It has a structure that can boost the output voltage of the photovoltaic panel and control the power by adjusting the duty cycle of the switching transistor. In single photovoltaic charging mode and when the battery charging power exceeds the maximum power of the photovoltaic panel, the bus voltage Vs decreases as the power demand increases. The DC / DC-3 circuit automatically reduces the charging current based on the voltage droop characteristic.

[0041] Based on the above solution, this utility model further specifies that the photovoltaic DC / DC circuit adopts a Boost topology and optimizes its power adaptive control logic in single photovoltaic charging mode to ensure that the system can still work stably when the photovoltaic power is insufficient.

[0042] The photovoltaic DC / DC circuit adopts a Boost structure, and the specific configuration is as follows: The circuit structure consists of an energy storage inductor, a high-frequency switching transistor (such as a MOSFET), a rectifier diode, and an output filter capacitor. The inductor input is connected to the positive terminal of the photovoltaic panel, and the output is connected to the common point of the drain of the switching transistor and the anode of the diode. The source of the switching transistor is grounded, and the cathode of the diode is connected in parallel with the capacitor and output to the common bus.

[0043] Its control logic is as follows: the duty cycle (D) of the switching transistor is adjusted by the PWM controller to achieve the boost conversion of the photovoltaic panel output voltage. When the bus voltage Vs is lower than the preset threshold, the circuit operates in MPPT mode, and D is dynamically adjusted by the perturbation observation method to make the photovoltaic panel operate at the maximum power point.

[0044] The adaptive control in single photovoltaic mode includes the following: when the battery charging power demand exceeds the current maximum power of the photovoltaic panel, the Boost circuit cannot provide enough energy, causing the bus voltage Vs to drop; at this time, the DC / DC-3 circuit automatically reduces the charging current based on the voltage droop characteristic, so that the system power demand is forced to match the actual output power of the photovoltaic, avoiding system collapse due to overload.

[0045] Specifically, such as Figures 1 to 4As shown, the DC / DC-3 circuit is a Buck circuit, including an inductor, a switching transistor, a diode, and a capacitor. It has a structure that adjusts the output current by controlling the on-time of the switching transistor through a closed loop to achieve precise control of the charging current. Its preset voltage-current droop curve is configured as follows: when the bus voltage Vs is the reference voltage V0, the rated charging current is output; when Vs decreases by a preset voltage difference ΔV, the output current decreases by a fixed proportion; its response time is configured to not exceed 10ms to adapt to rapid matching of photovoltaic or mains power fluctuations.

[0046] Based on the above solution, this utility model further specifies that the DC / DC-3 circuit of the unified power control module adopts a Buck step-down topology, and achieves precise adjustment of the charging current through closed-loop control and preset droop curve, so as to ensure the system's rapid response to photovoltaic or mains power fluctuations.

[0047] The DC / DC-3 circuit adopts a Buck structure, and the specific configuration is as follows: The circuit structure consists of an energy storage inductor, a high-frequency switching transistor, a freewheeling diode, and an output filter capacitor. The drain of the switching transistor is connected to the common bus (input terminal), and the source is connected to the common point between one end of the inductor and the cathode of the diode; the other end of the inductor is connected to the positive terminal of the battery and the positive terminal of the capacitor, and the anode of the diode and the negative terminal of the capacitor are grounded together.

[0048] The closed-loop control logic collects the output current in real time through a current sensor, compares it with the reference current, and outputs a PWM signal through a PI regulator to control the on-time Ton of the switching transistor, thereby achieving precise closed-loop control of the charging current with a control accuracy of ≤±0.5A.

[0049] The voltage-current droop curve has a preset reference voltage V0, such as 350V, corresponding to the rated charging current I0. When the bus voltage Vs decreases by a preset difference ΔV, the reference current decreases by a fixed proportion.

[0050] By optimizing the PI regulator parameters, the circuit's response time from voltage change to current stability is ≤10ms, ensuring rapid matching of upstream power fluctuations.

[0051] Specifically, such as Figures 1 to 4 As shown, the current limiting control structure of the DC / DC-3 circuit when the battery load voltage reaches the full charge threshold is configured such that the output voltage limiting ring automatically limits the charging current.

[0052] This invention further optimizes the full-charge current limiting control strategy of the DC / DC-3 circuit. Through precise threshold judgment and loop rate control, it achieves refined charging management of the battery, avoids overcharging, and extends battery life.

[0053] The full-charge current limiting control structure of the DC / DC-3 circuit is configured as follows: When the battery voltage approaches the full charge threshold, the output voltage loop will automatically limit the charging current to 0 to prevent overcharging. Specifically, such as Figures 1 to 4 As shown, the MPPT algorithm of the photovoltaic DC / DC circuit adjusts the operating point by detecting the direction of change in output power before and after the disturbance; when the power increases with the voltage, the voltage continues to increase; when the power decreases with the voltage, the voltage decreases until it stabilizes at the maximum power point.

[0054] Based on the above scheme, this utility model further clarifies that the MPPT algorithm used in the photovoltaic DC / DC circuit is the perturbation observation method. By periodically applying voltage perturbations and detecting the direction of power change, the operating point of the photovoltaic panel is dynamically adjusted to achieve accurate tracking of the maximum power point and ensure the efficient utilization of photovoltaic energy.

[0055] The core mechanism of the MPPT algorithm is as follows: Perturbation application: Apply a small perturbation, such as ±2V, to the output voltage of the photovoltaic panel at a fixed period, such as 0.1s-1s. The voltage is adjusted by regulating the duty cycle of the switching transistor in the photovoltaic DC / DC circuit, such as the Boost circuit. Power detection: Collect the output voltage V and current I of the photovoltaic panel before and after the disturbance, calculate the power P, and compare the difference ΔP between the two power values; If the power increases after the disturbance, i.e., ΔP > 0, meaning the power increases with the increase of voltage, then continue to apply the disturbance in the current direction; if the power decreases after the disturbance, i.e., ΔP < 0, meaning the power decreases with the increase of voltage, then apply the disturbance in the opposite direction; repeat the above process until the power change ΔP is less than a preset threshold such as 1W, at which point the photovoltaic panel stabilizes at the maximum power point.

[0056] Specifically, such as Figures 1 to 4 As shown, the voltage droop control is configured such that the output voltage decreases linearly as the output current increases, based on a second threshold V2.

[0057] Based on the above solution, this utility model further refines the voltage droop control logic of the AC / DC circuit. By setting the current threshold I1, the circuit working mode in different power ranges is clarified, so as to achieve smooth supplementation of photovoltaic power gap and improvement of system efficiency, and ensure stable operation of the system in a wide power range.

[0058] The core configuration of this voltage droop control is as follows: Interval division: Set a current threshold I1 such as 1A, a second threshold V2 such as 400V, and a third threshold such as 380V to form two working mode intervals; When the output current is higher than the current threshold I1, the output voltage of the AC / DC circuit decreases linearly with the increase of the output current, such as decreasing by 1V for every 1A. When the output current is less than the current threshold I1 or the bus voltage is greater than the second threshold V2, the AC / DC circuit enters burst mode. It first runs in standby mode, and resumes operation when the bus voltage Vs is lower than the third threshold of 380V.

[0059] The foregoing has illustrated and described the basic features, principles, and advantages of this utility model. It should be noted that this utility model is not limited to the above embodiments, but only to some embodiments. Any improvements and additions made without departing from the spirit and scope of this utility model are considered to be within the protection scope of this utility model.

Claims

1. A power adaptive control based AC-DC hybrid charging system, characterized in that, Includes a front-end energy input module, a unified power control module, and a battery load; The front-end energy input module includes at least one AC / DC circuit and at least one photovoltaic DC / DC circuit. The output terminals of each circuit are connected in parallel to form a common bus, and the bus voltage of the common bus is Vs. The unified power control module includes a DC / DC-3 circuit, whose input is connected to the common bus and whose output is connected to the battery load. The DC / DC-3 circuit is configured to uniformly control the battery charging current based on the voltage droop characteristic of the bus voltage Vs. When the bus voltage Vs decreases, the charging current is reduced; when the bus voltage Vs increases, the charging current is maintained or increased; and when the battery load voltage reaches a preset full charge threshold, the current is limited and the charging power is reduced.

2. The AC / DC hybrid charging system based on power adaptive control according to claim 1, characterized in that, The photovoltaic DC / DC circuit is configured such that when the bus voltage Vs is less than a preset first threshold V1, the photovoltaic panel output power is controlled using the MPPT algorithm; when the bus voltage Vs is greater than the preset first threshold V1, the output voltage high threshold current limiting control is used.

3. The AC / DC hybrid charging system based on power adaptive control according to claim 1, characterized in that, The AC / DC circuit is configured such that when the output current is greater than the current threshold I1, output voltage droop control is used to supplement the power gap of the photovoltaic DC / DC circuit; when the circuit output current is less than the current threshold I1 or the bus voltage is greater than the second threshold V2, burst operation mode is used.

4. The AC / DC hybrid charging system based on power adaptive control according to claim 1, characterized in that, The AC / DC circuit is a totem pole power factor correction circuit, including an inductor, at least four switching transistors and a freewheeling diode; one end of the inductor is connected to the mains input and the other end is connected to a bridge rectifier unit composed of switching transistors, which has a structure that realizes mains rectification and voltage boost by controlling the switching transistors to turn on and off, and outputs a stable DC voltage to the common bus.

5. The AC / DC hybrid charging system based on power adaptive control according to claim 1, characterized in that, The photovoltaic DC / DC circuit is a Boost circuit, including an inductor, a switching transistor, a diode, and a capacitor. It has a structure that can boost the output voltage of the photovoltaic panel and control the power by adjusting the duty cycle of the switching transistor. In single photovoltaic charging mode and when the battery charging power exceeds the maximum power of the photovoltaic panel, the bus voltage Vs decreases as the power demand increases. The DC / DC-3 circuit automatically reduces the charging current based on the voltage droop characteristic.

6. The AC / DC hybrid charging system based on power adaptive control according to claim 1, characterized in that, The DC / DC-3 circuit is a Buck circuit, including an inductor, a switching transistor, a diode, and a capacitor. It has a structure that adjusts the output current by controlling the on-time of the switching transistor through a closed loop to achieve precise control of the charging current. Its preset voltage-current droop curve is configured as follows: when the bus voltage Vs is higher than the reference voltage V0, the rated charging current is output according to the battery demand, wherein the reference voltage V0 is less than the second threshold V2; when Vs decreases by a preset voltage difference ΔV, the output current decreases by a fixed proportion. Its response time is configured to be no more than 10ms to accommodate rapid matching of photovoltaic or mains power fluctuations.

7. The AC / DC hybrid charging system based on power adaptive control according to claim 1, characterized in that, The DC / DC-3 circuit is configured with a current limiting control structure when the battery load voltage reaches the full charge threshold, wherein the output voltage limiting ring automatically limits the charging current.

8. The AC / DC hybrid charging system based on power adaptive control according to claim 2, characterized in that, The MPPT algorithm of the photovoltaic DC / DC circuit adjusts the operating point by detecting the direction of change in output power before and after the disturbance; when the power increases with the voltage, the voltage continues to increase; when the power decreases with the voltage, the voltage decreases until it stabilizes at the maximum power point.

9. The AC / DC hybrid charging system based on power adaptive control according to claim 3, characterized in that, The voltage droop control configuration is such that the output voltage is based on a second threshold V2 and decreases linearly with the increase of the output current, wherein the second threshold is lower than the first threshold; the burst operation mode is such that when the output current is less than the current threshold I1 or the bus voltage is greater than the second threshold V2, it operates in standby mode, and when the output voltage is lower than the third threshold V3, it resumes operation, wherein the third threshold V3 is lower than the second threshold V2 and higher than the reference voltage V0.

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