MPPT solar charging and discharging control system and method applied to photovoltaic system

Abstract

The invention relates to the technical field of photovoltaic systems, in particular to an MPPT (Maximum Power Point Tracking) solar charge and discharge control system and method applied to a photovoltaic system, and the system realizes efficient charge and discharge control and MPPT functions of the photovoltaic system through cooperative work of a power supply module, a sampling module, a processing module and a load module. The method specifically comprises the steps that a perturbation and observation method execution module is arranged in a processing module, small perturbation signals are periodically output through an MPPT control end, the output voltage of a photovoltaic system is adjusted, the output power is calculated by combining the output voltage and current signals, fed back by a sampling module, of the photovoltaic system, and the power before and after perturbation is compared to determine the change direction; if the power is increased, the current disturbance direction is kept, and if the power is reduced, reverse disturbance is performed, and the photovoltaic system works near the maximum power point through cyclic adjustment. The technical problems that in the background technology, an existing MPPT solar charging and discharging manager is high in hardware cost, low in power generation efficiency, poor in flexibility and insufficient in module stability can be solved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic system technology, and in particular to an MPPT solar charge and discharge control system and method applied to photovoltaic systems. Background Technology

[0002] The output power of a solar panel is not constant and is affected by solar irradiance, ambient temperature, and its own voltage. Under any given solar irradiance and temperature conditions, the panel has a specific operating point (the combination of voltage and current) where it can output maximum power; this operating point is called the "maximum power point" (MPP). Maximum power point tracking (MPPT) technology is an electronic technique designed to extract the maximum possible power from a photovoltaic (PV) array. It is highly dependent on the environment; changes in solar irradiance and temperature directly affect the efficiency of the PV array. The MPPT algorithm continuously adjusts electrical parameters to ensure that the PV system always remains at its maximum power point (MPP), thereby maximizing power output.

[0003] The existing MPPT solar charge and discharge manager still has room for optimization in terms of hardware cost control, power generation efficiency improvement, system design flexibility, and the stability and adaptability of each functional module. It cannot fully meet the needs of photovoltaic tracking systems for precise charging, power supply guarantee, and multi-scenario adaptation. Summary of the Invention

[0004] One objective of this invention is to propose an MPPT solar charge and discharge control system for photovoltaic systems, in order to solve the technical problems of existing MPPT solar charge and discharge managers in the background art, such as high hardware cost, low power generation efficiency, poor flexibility, and insufficient module stability.

[0005] Another objective of this invention is to propose an MPPT solar charge and discharge control method for photovoltaic systems, which applies the MPPT solar charge and discharge control system for photovoltaic systems described above.

[0006] To achieve this objective, the present invention adopts the following technical solution: An MPPT solar charge and discharge control system for photovoltaic systems includes a power supply module, a sampling module, a load module, and a processing module. The processing module is a 32-bit high-performance processor. The ports of the 32-bit high-performance processor include a power input terminal, a sampling input terminal, a sampling output terminal, a load output terminal, a load sampling terminal, and an MPPT control terminal. The 32-bit high-performance processor has a built-in perturbation observation method execution module. The input terminal of the power supply module is electrically connected to the output terminal of the external photovoltaic system, and the output terminal of the power supply module is electrically connected to the power input terminal of the 32-bit high-performance processor. The power supply module is used to receive the power output from the photovoltaic system and perform voltage conversion and voltage regulation to supply power to the processing module and other power-requiring modules in the system. The input terminal of the sampling module is electrically connected to the sampling input terminal of the 32-bit high-performance processor, and the output terminal of the sampling module is electrically connected to the sampling output terminal of the 32-bit high-performance processor. The sampling module is used to receive the sampling control signal from the processing module, collect the voltage and current signals of the photovoltaic system, and feed them back to the processing module. The input terminal of the load module is electrically connected to the load output terminal of the 32-bit high-performance processor, and the output terminal of the load module is electrically connected to the load sampling terminal of the 32-bit high-performance processor. The load module is used to receive the electrical energy output by the processing module and to feed back the load operating current and voltage signals to the processing module. The MPPT control terminal of the 32-bit high-performance processor is electrically connected to the output terminal of the photovoltaic system. The perturbation-observation method execution module is used to output control signals through the MPPT control terminal to adjust the output parameters of the photovoltaic system to achieve MPPT control. The control process of the perturbation observation method execution module includes: periodically outputting small perturbation signals through the MPPT control terminal to adjust the output voltage of the photovoltaic system; calculating the output power by combining the output voltage and current signals of the photovoltaic system fed back by the sampling module; comparing the power before and after the perturbation to determine the direction of change; if the power increases, maintaining the current perturbation direction; if the power decreases, performing a reverse perturbation; and cyclically adjusting to make the photovoltaic system work near the maximum power point.

[0007] Preferably, it also includes a battery management module; The ports of the 32-bit high-performance processor also include a battery control port; The input terminal of the battery management module is electrically connected to the battery control terminal of the 32-bit high-performance processor. The battery management module includes a battery body, a charging unit, a discharging unit, and a heating unit. The charging unit, discharging unit, and heating unit are used to receive control signals from the processing module to realize battery body charging and discharging and low-temperature heating protection.

[0008] Preferably, it also includes an auxiliary module; The ports of the 32-bit high-performance processor also include auxiliary interface ports; The auxiliary module includes an MCU indicator light, a temperature monitoring unit, an RTC clock, and an SWD programming unit; The MCU indicator light is electrically connected to the auxiliary interface of the processing module and is used to display the system working status; The temperature monitoring unit includes a circuit board NTC and a battery NTC. The circuit board NTC is mounted on the circuit board of the photovoltaic system, and the battery NTC is attached to the battery. The output terminals of the circuit board NTC and the battery NTC are electrically connected to the auxiliary interface terminal of the processing module, which is used to monitor the circuit board temperature and the battery temperature and feed them back to the processing module. The communication terminal of the RTC clock is electrically connected to the auxiliary interface terminal of the processing module to provide clock synchronization; The interface of the SWD programming unit is electrically connected to the auxiliary interface of the processing module, and is used for programming and debugging of the processing module.

[0009] Preferably, it also includes a communication module; The ports of the 32-bit high-performance processor also include a communication interface. The communication module includes an SN65HVD11DR driver, an optocoupler isolator, and a TVS diode. The serial port of the SN65HVD11DR driver is electrically connected to the communication interface of the processing module through the optocoupler isolator. The bus terminal of the SN65HVD11DR driver is used to connect to an external RS485 bus. The TVS diode is connected in parallel between the bus terminal and the ground terminal of the SN65HVD11DR driver. The SN65HVD11DR driver is used for differential signal transmission via RS485 bus to enable data transmission and reception between the processing module and external devices; The optocoupler isolator and TVS diode are used to achieve electrical protection.

[0010] Preferably, the power supply module includes a 12V power supply unit, an MCU power supply unit, and a step-down unit; The 12V power supply unit uses an XL7005A step-down converter to output 12V voltage; The MCU power supply unit uses an AMS1117-3.3 voltage regulator to convert 12V voltage into a preset stable voltage to power the processing module. The step-down unit uses a UCC27211 driver IC to reduce the 12V voltage to a preset stable voltage to power other low-voltage modules in the system.

[0011] Preferably, the sampling module includes a voltage sampling unit and a current sampling unit; The voltage sampling unit includes a differential amplifier and a voltage operational amplifier. The input terminals of the differential amplifier are electrically connected to the paths of the photovoltaic system output voltage, the load operating voltage, and the battery charging and discharging voltage, respectively, and are electrically connected to the sampling input terminal of the 32-bit high-performance processor. The output terminal of the differential amplifier is electrically connected to the sampling output terminal of the 32-bit high-performance processor via the voltage operational amplifier. The voltage sampling unit is used to collect the output voltage of the photovoltaic system, differentially collect the voltage signal through the differential amplifier, and amplify it through the operational amplifier before feeding it back to the processing module. The current sampling unit includes a sampling resistor and a current operational amplifier. The sampling resistor is connected in series in the path of the photovoltaic system output current, the load operating current, and the battery charging and discharging current. The input terminal of the current operational amplifier is electrically connected to both ends of the sampling resistor, and the output terminal of the current operational amplifier is electrically connected to the sampling output terminal. The current sampling unit is used to convert the current signal into a voltage drop, amplify it, and feed it back to the processing module.

[0012] Preferably, the load module includes a load body and a load protection unit; The input terminal of the load body is electrically connected to the load output terminal of the processing module for receiving power. The load protection unit is connected in series in the current path of the load body. The output terminal of the load protection unit is electrically connected to the load sampling terminal of the processing module to monitor the load operating status and trigger protection and feedback to the processing module in case of overload or overvoltage.

[0013] An MPPT solar charge / discharge control method for photovoltaic systems, applied to the MPPT solar charge / discharge control system for photovoltaic systems as described above, includes the following steps: S1: Start the control system. The photovoltaic system outputs electrical energy. The power supply module performs voltage conversion and regulation to supply power to the processing module and other power-requiring modules in the control system. S2: The processing module sends a control signal to the sampling module through the sampling input terminal. The sampling module collects the output voltage and current of the photovoltaic system, the operating voltage and current of the load, and the voltage and current of the battery, and feeds them back to the processing module through the sampling output terminal. S3: The perturbation observation method of the processing module executes the module by outputting a small perturbation signal to the photovoltaic system through the MPPT control terminal, and calculates the output power of the photovoltaic system by combining the signal fed back by the sampling module, and compares the power before and after the perturbation to determine the direction of change; S4: If the power increases after the disturbance, the current disturbance direction is maintained in the next cycle; if the power decreases after the disturbance, the disturbance signal is output in the opposite direction in the next cycle. The cycle of S3-S4 is repeated to make the photovoltaic system work near the maximum power point. At the same time, the 32-bit high-performance processor supplies power to the load module through the load output terminal, receives the load working signal through the load sampling terminal, and adjusts the power supply parameters in real time.

[0014] One of the above technical solutions has the following beneficial effects: (1) Reduce hardware costs: The perturbation and observation method only needs to collect voltage and current parameters. The algorithm logic is simple, the processor computing power requirement is low, and the functions of each module are focused and the structure is simplified. No additional high-cost hardware is required, which effectively controls the overall hardware cost.

[0015] (2) Improve power generation efficiency: MPPT control can quickly respond to environmental changes and ensure that the photovoltaic system continues to work near the maximum power point. Compared with traditional controllers, it brings an additional 15% to 30% power generation benefits. The benefits are more significant in low temperature and low light environments.

[0016] (3) Enhanced adaptability: The power supply module supports a wide range of photovoltaic input and the output voltage is adjustable. The load module adapts to different loads through dynamic parameter adjustment, which can meet the multi-scenario application needs of different photovoltaic systems and loads.

[0017] (4) Ensure operational stability: The power supply module stabilizes the voltage to avoid the impact of voltage fluctuations, the sampling module provides accurate data feedback to support reliable control, and the two-way interaction of each module forms a closed loop to reduce the risk of failure and improve the long-term operational reliability of the system. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the MPPT solar charge and discharge control system applied to photovoltaic systems. Figure 2 This is a schematic diagram of the power supply module in an MPPT solar charge and discharge control system applied to a photovoltaic system. Figure 3 This is a schematic diagram of the sampling module in an MPPT solar charge and discharge control system applied to a photovoltaic system. Figure 4 This is a schematic diagram of the load module in an MPPT solar charge and discharge control system applied to a photovoltaic system. Figure 5 This is a schematic diagram of the battery management module in an MPPT solar charge and discharge control system applied to a photovoltaic system. Figure 6 This is a schematic diagram of the structure of an auxiliary module in an MPPT solar charge and discharge control system applied to a photovoltaic system. In the attached diagram: Photovoltaic system 10, power supply module 20, sampling module 30, load module 40, processing module 50, battery management module 60, auxiliary module 70, communication module 80, 12V power supply unit 201, MCU power supply unit 202, step-down unit 203, voltage sampling unit 301, current sampling unit 302, battery body 601, charging unit 602, discharging unit 603, heating unit 604, MCU indicator light 701, temperature monitoring unit 702, RTC clock 703, SWD programming unit 704. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] like Figure 1-6 As shown, an MPPT solar charge and discharge control system applied to a photovoltaic system includes a power supply module 20, a sampling module 30, a load module 40, and a processing module 50. The processing module 50 is a 32-bit high-performance processor. The ports of the 32-bit high-performance processor include a power input terminal, a sampling input terminal, a sampling output terminal, a load output terminal, a load sampling terminal, and an MPPT control terminal. The 32-bit high-performance processor has a built-in perturbation observation method execution module. The input terminal of the power supply module 20 is electrically connected to the output terminal of the external photovoltaic system 10, and the output terminal of the power supply module 20 is electrically connected to the power input terminal of the 32-bit high-performance processor. The power supply module 20 is used to receive the power output from the photovoltaic system 10 and perform voltage conversion and voltage regulation to supply power to the processing module 50 and other power-requiring modules in the system. The input terminal of the sampling module 30 is electrically connected to the sampling input terminal of the 32-bit high-performance processor, and the output terminal of the sampling module 30 is electrically connected to the sampling output terminal of the 32-bit high-performance processor. The sampling module 30 is used to receive the sampling control signal of the processing module 50, collect the voltage and current signals of the photovoltaic system 10, and feed them back to the processing module 50. The input terminal of the load module 40 is electrically connected to the load output terminal of the 32-bit high-performance processor, and the output terminal of the load module 40 is electrically connected to the load sampling terminal of the 32-bit high-performance processor. The load module 40 is used to receive the electrical energy output by the processing module 50 and to feed back the load operating current and voltage signals to the processing module 50. The MPPT control terminal of the 32-bit high-performance processor is electrically connected to the output terminal of the photovoltaic system 10. The perturbation-observation method execution module is used to output a control signal through the MPPT control terminal to adjust the output parameters of the photovoltaic system 10 to achieve MPPT control. The control process of the perturbation observation method execution module includes: periodically outputting small perturbation signals through the MPPT control terminal to adjust the output voltage of the photovoltaic system 10; calculating the output power by combining the output voltage and current signals of the photovoltaic system 10 fed back by the sampling module 30; comparing the power before and after the perturbation to determine the direction of change; if the power increases, maintaining the current perturbation direction; if the power decreases, performing a reverse perturbation; and cyclically adjusting to make the photovoltaic system 10 work near the maximum power point.

[0021] This technical solution addresses the technical problems of existing MPPT solar charge / discharge managers, such as high hardware cost, low power generation efficiency, poor flexibility, and insufficient module stability. It achieves multi-dimensional optimization through module collaborative design, and the specific workflow is as follows: It is known that the output power of the photovoltaic system 10 is affected by sunlight and temperature, and its voltage is prone to fluctuations. Each module requires a stable voltage to function properly. Therefore, the input terminal of the power supply module 20 is directly connected to the output terminal of the external photovoltaic system 10. After receiving fluctuating photovoltaic power up to 60VDC, it converts the unstable voltage into a suitable voltage through internal voltage conversion circuits such as a step-down converter and voltage regulator, and filters out ripple through voltage regulation. Finally, the stable voltage is delivered to the processing module 50 through the power input terminal of the 32-bit high-performance processor. Simultaneously, it provides the required operating voltage to other power-demanding modules such as the sampling module 30 and the load module 40, preventing damage or malfunction caused by photovoltaic voltage fluctuations.

[0022] Meanwhile, the sampling module 30 operates through a process of "receiving control signals - acquiring signals - feeding back signals": the 32-bit high-performance processor sends sampling control signals through the sampling input terminal. After receiving the signals, the sampling module 30 acquires the voltage and current signals at the output terminal of the photovoltaic system 10 in real time. These two parameters are the core basis for calculating the photovoltaic output power and determining the maximum power point. After the acquisition is completed, the signal is fed back to the processing module 50 through the sampling output terminal, providing real-time and accurate data support for the MPPT control logic of the processing module 50.

[0023] Most importantly, the processing module 50, as the system core, uses a 32-bit high-performance processor STM32F334C8T6. Its power input is via VDD1, VDD2, and VDD3 pins connected to the 3.3V regulated power supply output from the power supply module 20, and VSS1-VSS3 pins connected to system ground. PA0-PA3 pins are connected to the photovoltaic current and voltage sampling signals ADC_I_OUT, ADC_V_OUT, ADC_I_IN, and ADC_V_IN as sampling inputs. PA4 is connected to the photovoltaic side switch SW_PV, PA5 to the battery output voltage Vo_BAT, PA6 to the battery relay control signal BAT_RL, and PA7 to the battery heating control signal BAT_heat. PA4-PA7 together constitute the MPPT control terminal and load output terminal. PA8 and PA9 serve as the high-resolution timer channels HrTIME_... CHA1 and HrTIME_CHA2 output PWM to drive buck unit 203 to adjust the output parameters of photovoltaic system 10. PB0 pin is connected to load current sampling signal ADC_I_RL, and PB1 pin is connected to PCB board temperature detection signal PCB_NTC as the sampling input terminal of sampling module 30. PB2 and PB3 pins are connected to LED2 and LED1 indicator lights respectively to form MCU indicator light 701 in auxiliary module 70. PB5, PB6, and PB7 pins are connected to the direction control terminal, serial port transmitter and receiver of RS485 transceiver respectively to form USART1_485_DIR, USART1_Tx, and USART1_Rx interfaces of communication module 80. PB13 pin is connected to battery pack temperature detection signal Batterys_NTC as the input terminal of temperature monitoring unit 702 in battery management module 60, used to detect the temperature of battery body 601.

[0024] Moreover, the built-in perturbation observation method execution module of the processing module 50 is designed directly to address the requirement in the background technology that "the MPPT algorithm needs to adjust electrical parameters to maintain the maximum power point": Specifically, the perturbation observation method execution module of the processing module 50 applies a small perturbation signal to the output terminal of the photovoltaic system 10 according to a set period, such as a millisecond period, through the MPPT control terminal. This signal will slightly adjust the output voltage of the photovoltaic system 10 to increase or decrease slightly.

[0025] After the disturbance signal is applied, the sampling module 30 collects the output voltage and output current signals of the photovoltaic system 10 in real time and feeds the collected signals back to the processing module 50. The processing module 50 calculates the output power of the photovoltaic system 10 after the disturbance based on the formula "power = voltage × current" and the feedback voltage and current signals, and compares it with the output power before the disturbance to determine whether the power change is upward or downward.

[0026] The specific calculation process is as follows: Processing module 50 first calculates the output power before the disturbance. ,in, and These are the voltage and current before the disturbance, respectively, as shown in the following formula: ; After the disturbance signal is applied, the sampling module 30 acquires the new voltage. and current Signal, calculate the power after disturbance ,in, and These are the voltage and current after the disturbance, respectively. The formulas are as follows: ; Processing module 50 will and Compare: If > This indicates that the perturbation direction is correct; continue perturbing in that direction. If < This indicates that the perturbation direction deviates from the maximum power point, requiring a reverse perturbation. Through this cyclic adjustment process, the operating point of the photovoltaic system 10 is kept oscillating near the maximum power point, continuously obtaining maximum output power. This solves the problem in the background technology of "maximum power point shift caused by changes in illumination and temperature".

[0027] Finally, the load module 40 addresses the problem that existing systems cannot meet the "multi-scenario adaptation" requirement through a two-way interactive design: on the one hand, the input end of the load module 40 receives the electrical energy delivered by the load output end of the processing module 50 to power external loads such as the drive components of a photovoltaic tracking system; on the other hand, the load module 40 collects its own operating current and voltage signals in real time and feeds them back to the processing module 50 through the load sampling end, so that the processor can grasp the load status in real time and flexibly adjust the power supply parameters such as current limit and voltage adaptation to adapt to the working requirements of different loads.

[0028] To elaborate further, it also includes a battery management module 60; The ports of the 32-bit high-performance processor also include a battery control port; The input terminal of the battery management module 60 is electrically connected to the battery control terminal of the 32-bit high-performance processor. The battery management module 60 includes a battery body 601, a charging unit 602, a discharging unit 603, and a heating unit 604. The charging unit 602, the discharging unit 603, and the heating unit 604 are used to receive control signals from the processing module 50 to realize the charging and discharging of the battery body 601 and low-temperature heating protection.

[0029] Specifically, the 32-bit high-performance processor sends a control signal to the charging unit 602 through the battery control terminal. When the battery body 601 needs to be charged, the control signal triggers the MOSFET in the charging unit 602 to turn on. The battery body 601 is connected to the power source, such as the photovoltaic system 10, through a diode and the power supply module 20 to process the electrical energy. At the same time, the resistor and current protection circuit in the charging unit 602 limits the charging current, and the voltage protection structure limits the charging voltage to prevent the charging current and voltage from exceeding the limits. When the battery body 601 is fully charged, the processing module 50 sends a signal to control the MOSFET to turn off to prevent the battery body 601 from reverse discharging.

[0030] When the load requires power from the battery body 601, the processing module 50 sends a conduction signal to the discharge unit 603 through the battery control terminal, causing the MOSFET in the discharge unit 603 to conduct. The electrical energy of the battery body 601 flows to the load through the diode. The diode can prevent the current from flowing in reverse. The current protection circuit and voltage protection structure monitor the supply current and voltage in real time to ensure that the current and voltage are within a safe range and avoid overcurrent and overvoltage damage to the battery body 601 and the load.

[0031] When the auxiliary module 70, such as the temperature monitoring unit 702, reports that the temperature of the battery body 601 is lower than the set threshold, the processing module 50 sends a start signal to the heating unit 604 through the battery control terminal, causing the MOSFET and P3HeatSwitch current control switch in the heating unit 604 to turn on, and the heating resistor to generate heat to heat the battery body 601. When the temperature of the battery body 601 reaches the set threshold, the processing module 50 sends a turn-off signal to turn off the MOSFET and current control switch, stopping the heating. The voltage protection diode in the circuit can ensure that the current flows in one direction and avoid damage to the heating unit 604 due to abnormal voltage.

[0032] Therefore, the linkage between the battery management module 60 and the processing module 50 enables automated control of battery charging, discharging, and heating without manual intervention, thus improving the system's intelligence level.

[0033] To elaborate further, it also includes an auxiliary module 70; The ports of the 32-bit high-performance processor also include auxiliary interface ports; The auxiliary module 70 includes an MCU indicator light 701, a temperature monitoring unit 702, an RTC clock 703, and an SWD programming unit 704; The MCU indicator light 701 is electrically connected to the auxiliary interface terminal of the processing module 50 and is used to display the system working status; The temperature monitoring unit 702 includes a circuit board NTC and a battery NTC. The circuit board NTC is mounted on the circuit board of the photovoltaic system 10, and the battery NTC is attached to the battery. The output terminals of the circuit board NTC and the battery NTC are electrically connected to the auxiliary interface terminal of the processing module 50, and are used to monitor the circuit board temperature and battery temperature and feed them back to the processing module 50. The communication terminal of the RTC clock 703 is electrically connected to the auxiliary interface terminal of the processing module 50 to provide clock synchronization; The interface of the SWD programming unit 704 is electrically connected to the auxiliary interface of the processing module 50, and is used for programming and debugging of the processing module 50.

[0034] First, the MCU indicator light 701 is electrically connected to the 32-bit high-performance processor through the auxiliary interface of the processing module 50. The processing module 50 outputs different level signals according to the working status of the control system, such as normal operation, fault, and charging, to control the on / off state and flashing frequency of the indicator light, so as to intuitively reflect the current working status of the system.

[0035] Secondly, the NTC circuit board is mounted on the circuit board of the photovoltaic system 10, and the battery NTC is attached to the battery; the resistance of the NTC negative temperature coefficient thermistor changes with temperature, decreasing when the temperature rises and increasing when the temperature falls; the temperature monitoring unit 702 converts the resistance change of the NTC into a voltage signal, which is fed back to the processing module 50 through the auxiliary interface terminal, and the processing module 50 calculates the real-time temperature of the circuit board and the battery based on the voltage signal.

[0036] Next, the RTC clock 703 is connected to the auxiliary interface of the processing module 50 through the communication terminal, providing the processing module 50 with a precise time reference, enabling the processing module 50 to implement time-related control logic such as timed sampling and timed data recording, and ensuring system time synchronization.

[0037] Finally, the interface of the SWD programming unit 704 is connected to the auxiliary interface of the processing module 50. Through the SWD serial line debugging protocol, programs such as the control program of the perturbation observation method execution module can be programmed into the 32-bit high-performance processor. Program debugging can also be performed during system operation, which facilitates system development, maintenance and function upgrades.

[0038] Therefore, the multi-functional design of the auxiliary module 70, from status indication, environmental monitoring, time synchronization to program debugging, comprehensively enhances the system's functionality and improves its ease of use, reliability and maintainability.

[0039] To elaborate further, it also includes a communication module 80; The ports of the 32-bit high-performance processor also include a communication interface. The communication module 80 includes an SN65HVD11DR driver, an optocoupler isolator, and a TVS diode. The serial port of the SN65HVD11DR driver is electrically connected to the communication interface of the processing module 50 through the optocoupler isolator. The bus terminal of the SN65HVD11DR driver is used to connect to an external RS485 bus. The TVS diode is connected in parallel between the bus terminal and the ground terminal of the SN65HVD11DR driver. The SN65HVD11DR driver is used for differential signal transmission via RS485 bus to realize data transmission and reception between the processing module 50 and external devices; The optocoupler isolator and TVS diode are used to achieve electrical protection.

[0040] First, the SN65HVD11DR driver in the communication module 80 is connected to the optocoupler via a serial port. The optocoupler is then connected to the communication interface of the processing module 50. When the processing module 50 sends data, the data is transmitted to the SN65HVD11DR driver via the communication interface and the optocoupler. The driver converts the data into RS485 differential signals and sends them to the external RS485 bus via the bus. Data sent by external devices is transmitted to the SN65HVD11DR driver via the RS485 bus. The driver converts the differential signals into serial data and transmits them to the communication interface of the processing module 50 via the optocoupler, thus realizing data interaction between the processing module 50 and external devices and building an RS485 communication network.

[0041] Next, the optocoupler transmits signals via optocoupler to achieve electrical isolation between the processing module 50 and the communication module 80, preventing external high voltage from being conducted to the processing module 50 through the communication line and damaging the core components; the TVS diode is connected in parallel between the bus terminal and the ground terminal of the SN65HVD11DR driver. When a transient high voltage occurs on the RS485 bus, such as a lightning strike or electrical interference, the TVS diode quickly conducts, clamping the high voltage within a safe range and protecting the SN65HVD11DR driver from damage.

[0042] Therefore, the design of the communication module 80 enables the system to interact with external devices such as monitoring terminals and host computers, allowing staff to remotely obtain system operating parameters such as power generation, battery status, and load status, facilitating remote monitoring and management of the system and reducing operation and maintenance costs.

[0043] To further explain, the power supply module 20 includes a 12V power supply unit 201, an MCU power supply unit 202, and a step-down unit 203; The 12V power supply unit 201 uses an XL7005A step-down converter to output 12V voltage; The MCU power supply unit 202 uses an AMS1117-3.3 voltage regulator to convert 12V voltage into a preset stable voltage to power the processing module 50. The step-down unit 203 adopts a UCC27211 driver IC to reduce the 12V voltage to a preset stable voltage to power other low-voltage power-requiring modules in the system.

[0044] First, the 12V power supply unit 201 receives the electrical energy output from the photovoltaic system 10 or the electrical energy after preliminary processing. Through an internal step-down converter such as the XL7005A step-down converter, the maximum 60VDC output voltage of the photovoltaic system 10 is converted into 12V DC voltage. Then, through a filter circuit such as diodes and inductors, the voltage ripple is filtered out, and a stable 12V voltage is output to provide power to modules in the control system that require 12V power supply, such as auxiliary module 70 and communication module 80.

[0045] Secondly, the MCU power supply unit 202 receives the 12V voltage output from the 12V power supply unit 201, and converts the 12V voltage into a stable 3.3V voltage through a voltage regulator such as an AMS1117-3.3 voltage regulator. At the same time, a filter circuit composed of multiple capacitors and inductors is used to filter out voltage ripple, ensuring that the output 3.3V voltage is fluctuation-free. Then, the 3.3V voltage is delivered to the power input terminal of the 32-bit high-performance processor to provide a suitable operating voltage for the processing module 50.

[0046] Finally, the step-down unit 203 receives the 12V voltage output from the 12V power supply unit 201 and uses a switching regulation method such as MOSFET control, combined with a driver IC such as UCC27211, to reduce the 12V voltage to the stable voltage required by other low-voltage power-demanding modules in the system, such as the voltage operational amplifier in the sampling module 30, such as 5V or 3.3V. By adjusting the duty cycle of the PWM signal, the output voltage is controlled to ensure stable power supply to the low-voltage modules.

[0047] In summary, the power supply module 20 adopts a hierarchical power supply design of "12V power supply unit 201 - MCU power supply unit 202 - step-down unit 203", which realizes the precise conversion from the high voltage of the photovoltaic system 10 to the voltage adapted to each module, meets the power supply requirements of different modules, and ensures that each module can work stably under the rated voltage.

[0048] To further explain, the sampling module 30 includes a voltage sampling unit 301 and a current sampling unit 302; The voltage sampling unit 301 includes a differential amplifier and a voltage operational amplifier. The input terminals of the differential amplifier are electrically connected to the paths of the output voltage of the photovoltaic system 10, the load operating voltage, and the battery charging and discharging voltage, respectively, and are electrically connected to the sampling input terminal of the 32-bit high-performance processor. The output terminal of the differential amplifier is electrically connected to the sampling output terminal of the 32-bit high-performance processor via the voltage operational amplifier. The voltage sampling unit 301 is used to collect the output voltage of the photovoltaic system 10. The voltage signal is differentially collected by the differential amplifier and amplified by the operational amplifier before being fed back to the processing module 50. The current sampling unit 302 includes a sampling resistor and a current operational amplifier. The sampling resistor is connected in series in the path of the output current of the photovoltaic system 10, the load operating current, and the battery charging and discharging current. The input terminal of the current operational amplifier is electrically connected to both ends of the sampling resistor, and the output terminal of the current operational amplifier is electrically connected to the sampling output terminal. The current sampling unit 302 is used to convert the current signal into a voltage drop, amplify it, and feed it back to the processing module 50.

[0049] First, after receiving the sampling control signal from the processing module 50, the differential amplifier input of the voltage sampling unit 301 performs differential sampling of the voltages at the output of the photovoltaic system 10, the load, and the charging and discharging of the battery. The differential sampling method can effectively suppress common-mode interference and improve voltage sampling accuracy. The sampled voltage signal is transmitted to the voltage operational amplifier, which amplifies the signal to match the sampling range of the ADC channel of the processing module 50. The amplified voltage signal is then fed back to the sampling input of the processing module 50 through the sampling output, so that the processing module 50 can calculate the power and implement MPPT control.

[0050] Since the sampling resistors of the current sampling unit 302 are connected in series in the paths of the output current, load operating current, and battery charging and discharging current of the photovoltaic system 10, a voltage drop proportional to the current will be generated when the current flows through the sampling resistor. Ohm's law: U=IR; the input terminal of the current amplifier is connected to both ends of the sampling resistor to amplify the voltage drop signal. The amplified current signal is converted into voltage form and fed back to the sampling input terminal of the processing module 50 through the sampling output terminal. The processing module 50 deduces the actual current value based on the relationship between the voltage drop and the resistance value of the sampling resistor.

[0051] Since the voltage sampling unit 301 adopts a design combining a differential amplifier and a voltage operational amplifier, it not only suppresses common-mode interference but also expands the sampling signal range, ensuring the accuracy of the output voltage sampling of the photovoltaic system 10. The current sampling unit 302 realizes current-to-voltage conversion through a series sampling resistor and is amplified by a current operational amplifier. The sampling principle is simple, the cost is low, and the sampling accuracy can meet the needs of MPPT control, load monitoring, and battery management.

[0052] Because the sampling module 30 simultaneously collects voltage and current signals from the photovoltaic system 10, the load, and the battery, it provides comprehensive data support for the processing module 50. This enables the processing module 50 to simultaneously perform MPPT control, load protection, and battery charge / discharge management, improving the system's integration and control accuracy. Accurate sampling data is the foundation of MPPT control. The design of the sampling module 30 ensures that the processing module 50 can accurately calculate the output power of the photovoltaic system 10, thereby precisely adjusting the disturbance direction to maximize the power generation efficiency of the photovoltaic system 10, while also providing a reliable basis for the safety protection of the load and battery.

[0053] To further explain, the load module 40 includes a load body 401 and a load protection unit 402; The input terminal of the load body 401 is electrically connected to the load output terminal of the processing module 50 for receiving power. The load protection unit 402 is connected in series in the current path of the load body 401. The output terminal of the load protection unit 402 is electrically connected to the load sampling terminal of the processing module 50. It is used to monitor the working status of the load and trigger protection and feedback to the processing module 50 when there is overload or overvoltage.

[0054] Specifically, the processing module 50 supplies stable operating power to the load module 40 through the load output terminal. After receiving this operating power, the load body 401, such as the drive motor of a photovoltaic tracking system or the input terminal of a monitoring device, operates normally. At the same time, the load protection unit 402 is connected in series in the current path of the load body 401 to monitor the current and voltage signals during the load's operation in real time. When the load experiences an overload current exceeding the rated value or an overvoltage exceeding the rated value, the load protection unit 402 triggers a protection mechanism, such as cutting off part of the circuit or limiting the current / voltage. Simultaneously, the overload and overvoltage signals are fed back to the processing module 50 through the load sampling terminal. After receiving the feedback signal, the processing module 50 can further adjust the power parameters at the load output terminal or issue a fault warning signal to prevent the load from being damaged due to overload or overvoltage.

[0055] An MPPT solar charge / discharge control method for photovoltaic systems, applied to the MPPT solar charge / discharge control system for photovoltaic systems as described above, includes the following steps: S1: Start the control system. The photovoltaic system 10 outputs electrical energy. The power supply module 20 performs voltage conversion and regulation to supply power to the processing module 50 and other power-requiring modules in the control system. S2: Processing module 50 sends a control signal to sampling module 30 through sampling input terminal. Sampling module 30 collects output voltage and current, load operating voltage and current, and battery voltage and current signals of photovoltaic system 10, and feeds them back to processing module 50 through sampling output terminal. S3: The disturbance observation method execution module of the processing module 50 outputs a small disturbance signal to the photovoltaic system 10 through the MPPT control terminal, calculates the output power of the photovoltaic system 10 by combining the signal fed back by the sampling module 30, and determines the direction of change by comparing the power before and after the disturbance. S4: If the power increases after the disturbance, the current disturbance direction is maintained next time; if the power decreases after the disturbance, the disturbance signal is output in the opposite direction next time. S3-S4 cycle to make the photovoltaic system 10 work near the maximum power point; at the same time, the 32-bit high-performance processor supplies power to the load module 40 through the load output terminal, receives the load working signal through the load sampling terminal, and adjusts the power supply parameters in real time.

[0056] The control method follows a "start-sampling-control-adjustment" logic, with a clear and controllable closed-loop process. This ensures the orderly progress of the system from startup to stable operation, reducing the risk of system startup failure or operational malfunction. The specific process is as follows: System startup and power supply phase S1: After the control system starts up, the external photovoltaic system 10 begins to output electrical energy; the power supply module 20 receives this electrical energy and converts the voltage output by the photovoltaic system 10 into a stable voltage through internal step-down and voltage regulation circuits such as the XL7005A step-down converter and the AMS1117-3.3 voltage regulator, and respectively sends it to the processing module 5032-bit high-performance processor, sampling module 30, load module 40, battery management module 60, etc., to ensure that each module obtains the appropriate operating voltage and completes the system initialization power supply.

[0057] In the data sampling phase S2: the 32-bit high-performance processor sends a sampling control signal to the sampling module 30 through the sampling input terminal; after receiving the signal, the sampling module 30 collects the voltage and current signals of the output terminal of the photovoltaic system 10, the operating voltage and current signals of the load module 40, and the battery voltage and current signals of the battery management module 60 respectively; after the acquisition is completed, the sampling module 30 feeds back all signals to the processing module 50 through the sampling output terminal, and the processing module 50 performs AD conversion and data preprocessing on the signals.

[0058] MPPT Disturbance and Power Calculation Stage S3: The disturbance observation method execution module built into the processing module 50 periodically sends small disturbance signals to the output terminal of the photovoltaic system 10 through the MPPT control terminal to adjust the output voltage of the photovoltaic system 10; combined with the output voltage and current signals of the photovoltaic system 10 fed back by the sampling module 30, the processing module 50 calculates the output power of the photovoltaic system 10 after the disturbance according to the formula "power = voltage × current", and retrieves the power data stored before the disturbance to compare and determine whether the power change direction is increasing or decreasing.

[0059] Cyclic adjustment and load control stage S4: If the power increases after the disturbance, the next disturbance will maintain the current direction; if the power decreases after the disturbance, the next disturbance will be applied in the opposite direction. By cyclically executing S3-S4, the operating point of the photovoltaic system 10 is always near the maximum power point, continuously obtaining the maximum output power. At the same time, the processing module 50 supplies electrical energy to the load module 40 through the load output terminal, and receives load operating status signals such as current and voltage through the load sampling terminal. Based on the signals, it adjusts the power supply parameters of the load output terminal in real time, such as voltage magnitude and current limit, to ensure stable power supply to the load.

[0060] Furthermore, in the various embodiments of the present invention, each functional unit can be integrated into a processing module (50), or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A MPPT solar charge-discharge control system applied to a photovoltaic system, characterized in that, It comprises a power supply module (20), a sampling module (30), a load module (40) and a processing module (50); The processing module (50) is a 32-bit high-performance processor, the port of the 32-bit high-performance processor comprises a power input end, a sampling input end, a sampling output end, a load output end, a load sampling end and an MPPT control end, and the 32-bit high-performance processor is built-in with a perturb and observe method execution module; The input end of the power supply module (20) is electrically connected with the output end of an external photovoltaic system (10), the output end of the power supply module (20) is electrically connected with the power input end of the 32-bit high-performance processor, and the power supply module (20) is used for receiving the output electric energy of the photovoltaic system (10) and performing voltage conversion and voltage stabilization processing to supply power to the processing module (50) and other power modules in the system. The input end of the sampling module (30) is electrically connected with the sampling input end of the 32-bit high-performance processor, the output end of the sampling module (30) is electrically connected with the sampling output end of the 32-bit high-performance processor, the sampling module (30) is used for receiving the sampling control signal of the processing module (50), collecting the voltage and current signals of the photovoltaic system (10) and feeding back to the processing module (50). The input end of the load module (40) is electrically connected with the load output end of the 32-bit high-performance processor, the output end of the load module (40) is electrically connected with the load sampling end of the 32-bit high-performance processor, and the load module (40) is used for receiving the output electric energy of the processing module (50) and feeding back the load working current and voltage signals to the processing module (50). The MPPT control end of the 32-bit high-performance processor is electrically connected with the output end of the photovoltaic system (10), and the perturb and observe method execution module is used for outputting a control signal through the MPPT control end to adjust the output parameters of the photovoltaic system (10) to realize MPPT control. The control process of the perturb and observe method execution module comprises: periodically outputting a small perturbation signal through the MPPT control end, adjusting the output voltage of the photovoltaic system (10), combining the output voltage and current signals of the photovoltaic system (10) fed back by the sampling module (30) to calculate the output power, comparing the power before and after the perturbation to determine the change direction, if the power increases, the current perturbation direction is maintained, if the power decreases, the perturbation direction is reversed, and the photovoltaic system (10) is adjusted in a cycle to work near the maximum power point.

2. The MPPT solar charge-discharge control system applied to a photovoltaic system according to claim 1, characterized in that, It further comprises a battery management module (60); The port of the 32-bit high-performance processor further comprises a battery control end; The input end of the battery management module (60) is electrically connected with the battery control end of the 32-bit high-performance processor, the battery management module (60) comprises a battery body (601), a charging unit (602), a discharging unit (603) and a heating unit (604), and the charging unit (602), the discharging unit (603) and the heating unit (604) are used for receiving the control signal of the processing module (50) to realize charging and discharging of the battery body (601) and low-temperature heating protection.

3. The MPPT solar charge-discharge control system applied to a photovoltaic system according to claim 2, characterized in that, It further comprises an auxiliary module (70); The port of the 32-bit high-performance processor further comprises an auxiliary interface end; The auxiliary module (70) comprises an MCU indicator light (701), a temperature monitoring unit (702), an RTC clock (703), and an SWD burning unit (704); The MCU indicator light (701) is electrically connected with the auxiliary interface end of the processing module (50), and is used for displaying the working state of the system. The temperature monitoring unit (702) comprises a circuit board NTC and a battery NTC, the circuit board NTC is attached to the circuit board of the photovoltaic system (10), and the battery NTC is attached to the battery; the output end of the circuit board NTC and the output end of the battery NTC are electrically connected with the auxiliary interface end of the processing module (50), and are used for monitoring the circuit board temperature and the battery temperature and feeding back to the processing module (50); The communication end of the RTC clock (703) is electrically connected with the auxiliary interface end of the processing module (50), and is used for providing clock synchronization; The interface of the SWD burning unit (704) is electrically connected with the auxiliary interface end of the processing module (50), and is used for program burning and debugging of the processing module (50).

4. The MPPT solar charge-discharge control system for photovoltaic system according to claim 1, characterized in that, Further comprising a communication module (80); The port of the 32-bit high-performance processor further comprises a communication interface end; The communication module (80) comprises an SN65HVD11DR driver, an optical coupler isolator, and a TVS diode; The serial port of the SN65HVD11DR driver is electrically connected with the communication interface end of the processing module (50) through the optical coupler isolator, the bus end of the SN65HVD11DR driver is used for connecting an external RS485 bus, and the TVS diode is connected in parallel between the bus end and the ground end of the SN65HVD11DR driver; The SN65HVD11DR driver is used for differential signal transmission through the RS485 bus, so as to realize data transmission and reception between the processing module (50) and external equipment; The optical coupler isolator and the TVS diode are used for electrical protection.

5. The MPPT solar charge-discharge control system for photovoltaic system according to claim 1, characterized in that, The power supply module (20) comprises a 12V power supply unit (201), an MCU power supply unit (202), and a step-down unit (203); The 12V power supply unit (201) adopts an XL7005A step-down converter, and is used for outputting a 12V voltage; The MCU power supply unit (202) adopts an AMS1117-3.3 voltage stabilizer, and is used for converting the 12V voltage into a preset stable voltage, so as to supply power to the processing module (50); The step-down unit (203) adopts a UCC27211 driving IC mode, and is used for reducing the 12V voltage into a preset stable voltage, so as to supply power to other low-voltage power modules in the system.

6. The MPPT solar charge-discharge control system for photovoltaic system according to claim 3, characterized in that, The sampling module (30) comprises a voltage sampling unit (301) and a current sampling unit (302); The voltage sampling unit (301) comprises a differential amplifier and a voltage operational amplifier, input ends of the differential amplifier are electrically connected in paths of the output voltage of the photovoltaic system (10), the working voltage of the load, and the charging and discharging voltage of the battery, and are electrically connected with a sampling input end of the 32-bit high-performance processor, an output end of the differential amplifier is electrically connected with a sampling output end of the 32-bit high-performance processor through the voltage operational amplifier, and the voltage sampling unit (301) is used for collecting the output voltage of the photovoltaic system (10), differentially collecting the voltage signal through the differential amplifier, and feeding back to the processing module (50) after amplification by the operational amplifier; The current sampling unit (302) comprises a sampling resistor and a current operational amplifier, the sampling resistor is connected in series in paths of the output current of the photovoltaic system (10), the working current of the load, and the charging and discharging current of the battery, input ends of the current operational amplifier are electrically connected with both ends of the sampling resistor, and an output end of the current operational amplifier is electrically connected with the sampling output end, and the current sampling unit (302) is used for converting the current signal into a voltage drop and feeding back to the processing module (50) after amplification.

7. The MPPT solar charge-discharge control system for photovoltaic system according to claim 1, characterized in that, The load module (40) comprises a load body (401) and a load protection unit (402); An input end of the load body (401) is electrically connected with a load output end of the processing module (50) and is used for receiving power supply; The load protection unit (402) is connected in series in a current path of the load body (401), an output end of the load protection unit (402) is electrically connected with a load sampling end of the processing module (50) and is used for monitoring the working state of the load, triggering protection and feeding back to the processing module (50) when overload or overvoltage occurs.

8. A MPPT solar charge-discharge control method applied to a photovoltaic system, characterized in that, The application is applied to the MPPT solar charging and discharging control system for the photovoltaic system in any one of claims 1-7, and comprises the following steps: S1: starting the control system, the photovoltaic system (10) outputs electric energy, the power supply module (20) performs voltage conversion and voltage stabilization processing, and supplies power to the processing module (50) and other power-consuming modules in the control system; S2: the processing module (50) sends a control signal to the sampling module (30) through a sampling input end, the sampling module (30) collects the output voltage and current of the photovoltaic system (10), the working voltage and current of the load, and the battery voltage and current signal, and feeds back to the processing module (50) through a sampling output end; S3: a perturbation and observation method execution module of the processing module (50) outputs a small perturbation signal to the photovoltaic system (10) through an MPPT control end, calculates the output power of the photovoltaic system (10) in combination with the signal fed back by the sampling module (30), compares the power before and after the perturbation to determine the change direction; S4: if the power increases after the perturbation, the current perturbation direction is maintained in the next time, if the power decreases after the perturbation, the perturbation signal is reversely output in the next time, and the steps S3-S4 are circularly performed to make the photovoltaic system (10) work near the maximum power point; meanwhile, the 32-bit high-performance processor supplies power to the load module (40) through a load output end, receives the load working signal through a load sampling end, and adjusts the power supply parameters in real time.

Images