An irrigation system and method of controlling the same

Abstract

This invention discloses an irrigation system and its control method, specifically relating to the field of photovoltaic power generation and energy storage control technology. The method includes: determining whether the photovoltaic module is generating electricity; if not, waking it from standby mode; if so, executing MPPT tracking and adjusting the DC / DC duty cycle, while simultaneously generating feedback signals based on battery voltage and temperature for MPPT and duty cycle adjustment; performing safety monitoring on the battery; charging if normal, and protecting and returning to standby mode if abnormal; disconnecting the main charging circuit after full charge; and receiving irrigation commands to control the battery to supply power to the water pump when not locked. The system includes: photovoltaic modules, an MPPT controller, an energy storage battery, a detection circuit, a control circuit, and irrigation equipment. These components are integrated according to power and signal connection relationships, providing a hardware architecture for executing the method. This invention significantly improves charging efficiency and environmental adaptability through coordinated closed-loop control between the photovoltaic and energy storage sides, and provides a hardware architecture for coordinated operation.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation and energy storage control technology, and more specifically, to an irrigation system and its control method. Background Technology

[0002] Currently, a common photovoltaic (PV) irrigation system in off-grid agricultural irrigation scenarios includes PV modules, an MPPT controller, an energy storage battery, and an irrigation pump; MPPT stands for Maximum Power Point Tracking. The control method of this PV irrigation system is as follows: PV modules generate direct current (DC) under sunlight; the MPPT controller tracks the maximum power point of the PV modules and charges the energy storage battery after voltage conversion via an internal DC / DC circuit; simultaneously, the system monitors the voltage and temperature of the energy storage battery in real time through an independent detection circuit. When the battery voltage reaches the full charge threshold or the temperature exceeds the safety limit, the protection circuit executes a charge / discharge protection action to cut off charging; when irrigation is needed, the energy storage battery discharges, and the output control circuit powers the water pump to achieve irrigation.

[0003] However, the aforementioned system suffers from a problem in its control method: the three stages—MPPT charging control, energy storage battery state detection, and charge / discharge protection—are independent of each other, lacking coordination and closed-loop feedback mechanisms. Specifically, the MPPT controller is only responsible for maximum power point tracking and voltage conversion, without receiving battery state information to dynamically adjust the charging strategy; the state detection circuit only monitors parameters but does not participate in charging decisions; and the protection circuit is only passively cut off when a threshold is triggered, failing to establish linkage with other stages. This discrete control approach prevents the system from timely and coordinatedly adjusting charging parameters to achieve optimal charging when illumination changes or the battery approaches a critical state. It also makes it difficult to implement preventative closed-loop protection when abnormal conditions occur, impacting the system's charging efficiency, safety, and range.

[0004] Therefore, this application proposes an irrigation system and its control method as a further improvement. This integrates MPPT (Maximum Power Point Tracking), energy storage battery state detection, and charge / discharge protection into a unified closed-loop control process. This significantly improves photovoltaic charging efficiency, enhances the safety and reliability of the energy storage battery, and effectively extends the system's continuous operating range. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide an irrigation system and a control method thereof to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a control method for an irrigation system, comprising the following steps: S1: Determine if the photovoltaic module is outputting electrical energy; if so, proceed to S2. S2: Based on the detected output voltage and output current of the photovoltaic module, the MPPT controller performs maximum power point tracking control, calculates the current power point, and performs buck / boost voltage regulation by adjusting the duty cycle of the DC / DC circuit inside the MPPT controller; at the same time, based on the detected battery voltage and battery temperature of the energy storage battery, a feedback signal is generated and applied to the maximum power point tracking control and the duty cycle adjustment of the DC / DC circuit; S3: Perform safety monitoring on the energy storage battery, including battery voltage, battery temperature, charging current and / or state of charge. If the monitoring results are normal, control the energy storage battery to charge, and then execute S4; If the monitoring results are abnormal, including overvoltage, overtemperature, overcurrent and / or state of charge exceeding the limit, the protection mode is entered: the charging circuit is cut off, the maximum power point tracking control is suspended, the system is locked to prevent the energy storage battery from discharging, and then it returns to S1.

[0007] S4: Determine if the energy storage battery is fully charged; If not fully filled, return to S1; If fully charged, the control circuit returns a full charge signal, disconnects the main charging circuit, and charging ends. S5: When an irrigation command is received and the system is not in a protected lockout state, the control circuit controls whether the energy storage battery supplies power to the irrigation equipment, thereby controlling the start and stop of the irrigation equipment.

[0008] Furthermore, in S2, the output voltage and output current of the photovoltaic module are collected by the MPPT controller, and maximum power point tracking control is performed, as well as the current power point is calculated; in S2 and S3, the detection data of the energy storage battery are collected by the detection circuit and provided to the control circuit.

[0009] Furthermore, the maximum power point tracking control employs a perturbation-observation method, which tracks the maximum power point by periodically perturbing the duty cycle of the DC / DC circuit and observing the changes in the output power of the photovoltaic module.

[0010] Furthermore, in S3, the overvoltage threshold for the safety monitoring energy storage battery voltage is set to 1.05 times the rated voltage of the energy storage battery, and the overtemperature threshold for the energy storage battery temperature is set to 60°C.

[0011] Furthermore, the feedback signal is used to correct the tracking direction of the MPPT control and / or correct the duty cycle adjustment step size of the DC / DC circuit.

[0012] An irrigation system for performing the control method described above includes: Photovoltaic modules; MPPT controller, wherein the power input terminal of the MPPT controller is electrically connected to the power output terminal of the photovoltaic module; An energy storage battery, wherein the power input terminal of the energy storage battery is electrically connected to the power output terminal of the MPPT controller; A detection circuit, wherein the power input terminal of the detection circuit is electrically connected to the power output terminal of the energy storage battery; and the signal input terminal of the detection circuit is signal-connected to the signal output terminal of the energy storage battery. A control circuit, wherein the power input terminal of the control circuit is electrically connected to the power output terminal of the energy storage battery; the signal input terminal of the control circuit is signal-connected to the signal output terminal of the detection circuit; the control circuit is bidirectionally signal-connected to the MPPT controller; and the signal output terminal of the control circuit is signal-connected to the signal input terminal of the energy storage battery. An irrigation device, wherein the power input terminal of the irrigation device is electrically connected to the power output terminal of the energy storage battery.

[0013] Furthermore, the MPPT controller integrates a DC / DC circuit, which adopts a Buck topology, a Boost topology, or a Buck-Boost topology.

[0014] Furthermore, the power input terminal of the MPPT controller is electrically connected to the power output terminal of the photovoltaic module to collect the output voltage and output current of the photovoltaic module; the signal output terminal of the energy storage battery is set as the detection point of the energy storage battery; the signal input terminal of the detection circuit is connected to the detection point to collect the voltage, current and temperature of the energy storage battery.

[0015] Furthermore, the control circuit uses an STM32 series or GD32 series main control chip.

[0016] Furthermore, the MPPT controller, the energy storage battery, the detection circuit, and the control circuit are integrated into a portable component, and the connection interface between the photovoltaic module and the irrigation equipment is located on the outer shell of the portable component.

[0017] The technical effects and advantages of this invention are as follows: 1. Compared with existing technologies, by determining whether the photovoltaic module is generating electricity, coupling MPPT (Maximum Power Point Tracking) with battery status feedback, and switching between charging, protection, or standby modes in real time based on safety monitoring results, collaborative closed-loop control between the photovoltaic side and the energy storage side during charging is achieved, significantly improving the system's charging efficiency and environmental adaptability. By integrating the photovoltaic module, MPPT controller, energy storage battery, detection circuit, control circuit, and irrigation equipment into a single unit according to specific power and signal connection relationships, and clarifying the signal flow between the detection circuit and the control circuit, a coordinated hardware architecture is provided for executing the control method.

[0018] 2. Compared with existing technologies, by clearly defining the division of labor between the detection circuit and the control circuit, the signal acquisition and control logic are separated, improving the modularity of the system and the reliability of signal processing; limiting MPPT to use the perturbation observation method combined with the control circuit to provide overvoltage and overtemperature thresholds provides an feasible and optimal solution for maximum power point tracking and battery safety protection; using feedback signals to correct the MPPT tracking direction and duty cycle adjustment step size optimizes dynamic response performance; setting a standby wake-up time interval achieves a balance between low power consumption and fast response; and by limiting the DC / DC topology type, control chip model, and energy storage battery specifications, the system's versatility and deployment convenience are enhanced. Attached Figure Description

[0019] Figure 1 This is a flowchart of the control method of the present invention.

[0020] Figure 2 This is a system block diagram of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1: As shown in the attached document Figure 1 The diagram illustrates a control method for an irrigation system. This method is implemented by a control circuit executing a control program embedded within it; the control circuit can employ an STM32 series microcontroller. Specifically, it includes the following steps: S1: Determine if the photovoltaic module is outputting power; the MPPT controller collects the output voltage and current of the photovoltaic module and sends the detected values ​​to the control circuit. The control circuit determines whether the voltage is greater than a valid threshold; for example, this threshold is set to 5V; If there is no effective power output, such as at night or on a cloudy day when the photovoltaic modules have no power output, the irrigation system enters a low-power standby mode and periodically wakes up to detect the light conditions at a preset time interval. That is, at this time, the control circuit sets a preset time interval to wake up the detection circuit to re-detect the light conditions until effective power output is detected after the light is restored, and then exits the standby mode to execute S2. The preset time interval in the standby mode can be set to 30 seconds.

[0023] If there is effective electrical energy output, then execute S2 directly; S2: MPPT charging control and status feedback.

[0024] When the photovoltaic (PV) module is detected to be outputting power, the MPPT controller performs maximum power point tracking (MPPT) control based on the detected output voltage and current of the PV module. It calculates the current power point, employing a perturbation-observation method. This involves periodically perturbing the duty cycle of the internal DC / DC circuit of the MPPT controller and observing changes in the PV module's output power to track the maximum power point. Essentially, it performs Buck / Boost voltage regulation by adjusting the duty cycle of the internal DC / DC circuit. For example, if the power increases, the perturbation continues in the same direction; if the power decreases, the perturbation is reversed, thus ensuring the PV module operates stably at its maximum power point. Simultaneously, the control circuit generates feedback signals based on the battery voltage and temperature detected by the detection circuit. For example, when the battery voltage is low, the duty cycle adjustment step size is reduced to avoid overcurrent; when the battery temperature rises, the charging current is appropriately reduced. This feedback signal is used for MPPT algorithm and DC / DC circuit duty cycle adjustment, forming a closed-loop control. In other words, the feedback signal is used to correct the tracking direction of the MPPT control and / or correct the duty cycle adjustment step size of the DC / DC circuit.

[0025] S3: Safety Monitoring and Charging Control. The control circuit performs safety monitoring of the energy storage battery based on the detection circuit. Monitoring parameters include battery voltage, battery temperature, charging current, and / or state of charge (SOC). The SOC is set as follows: Overvoltage threshold is 1.05 times the rated voltage of the energy storage battery; for example, for a 48V lithium battery pack with a rated voltage of 48V, the overvoltage threshold is 50.4V. Alternatively, the absolute cutoff voltage of 54.6V can be used, and 1.05 times this, 57.33V, can be used as the hardware protection threshold. In this embodiment, 54.6V is used as the full charge cutoff voltage. The overtemperature threshold is 60℃. If all parameters are within the safe range; for example, if the battery voltage is below the full charge threshold of 54.6V, the temperature is below 60℃, the charging current is below the rated current, and the SOC is below 100%, then the monitoring results are normal. If the monitoring results are normal, the control circuit controls the charging of the energy storage battery through the MPPT controller and DC / DC circuit, and then executes S4; If the monitoring results are abnormal, i.e., any parameter such as overvoltage, overtemperature, overcurrent, or SOC exceeds the safety limit, the system will immediately enter the protection mode: cut off the charging circuit by sending a stop command to the DC / DC circuit, suspend the maximum power point tracking control by sending a pause tracking command to the MPPT controller, lock the system to prevent the energy storage battery from discharging, and then return to the standby mode of S1, waiting for the abnormality to be eliminated before resuming.

[0026] S4: Determine if the energy storage battery is fully charged. During charging, the control circuit continuously monitors the battery voltage. When the battery voltage reaches a preset full-charge threshold; for example, 54.6V for a 48V lithium battery pack, which is 1.05 times the rated voltage, it is considered fully charged. The control circuit can then send a full-charge return signal via an indicator light or communication interface, disconnecting the main charging circuit and stopping the DC / DC circuit, thus ending the charging process normally. If not fully charged, it returns to S1 to continue the cycle of detection and charging.

[0027] S5: When an irrigation command is received and the system is not in a protection lockout state, the control circuit controls whether the energy storage battery supplies power to the irrigation equipment, thereby controlling the start and stop of the irrigation equipment. Specifically, when the control circuit receives an external irrigation command, such as one from a button, remote control, or timer, it first determines whether the system is in a protection lockout state. If not locked, the control circuit sends a power supply command to the irrigation equipment through the DC output interface, discharging the energy storage battery and starting the irrigation equipment. During irrigation, the control circuit continuously monitors the battery status; if any abnormality occurs, irrigation is immediately stopped and the system returns to protection mode.

[0028] In a preferred embodiment, as shown in the appendix Figure 1 As shown, in S2, the output voltage and output current of the photovoltaic module are collected by the MPPT controller, and maximum power point tracking control is performed, as well as the current power point is calculated; in S2 and S3, the detection data of the energy storage battery are collected by the detection circuit and provided to the control circuit.

[0029] Example 2: As shown in the attached document Figure 2 As shown, an irrigation system that performs the above control method includes: a photovoltaic module, an MPPT controller, an energy storage battery, a detection circuit, a control circuit, and irrigation equipment; Photovoltaic modules convert solar energy into direct current (DC) electricity.

[0030] The MPPT controller's power input terminal is electrically connected to the photovoltaic module's power output terminal to collect the photovoltaic module's output voltage and output current. The MPPT controller integrates a DC / DC circuit; this embodiment uses a Buck-Boost topology, but Buck or Boost topologies are also optional to accommodate a wide input voltage range. The MPPT controller is responsible for tracking the maximum power point under the instructions of the control circuit and converting electrical energy into voltage and current suitable for charging the energy storage battery.

[0031] The energy storage battery uses a 48V lithium battery pack. The power input terminal of the energy storage battery is electrically connected to the power output terminal of the MPPT controller. The energy storage battery supplies power to the irrigation equipment, control circuit, and detection circuit; that is, the power output terminal of the energy storage battery is connected to the power input terminals of the irrigation equipment, control circuit, and detection circuit, respectively. The power input terminal of the detection circuit is connected to the power output terminal of the energy storage battery to ensure that the detection circuit can still work when there is no light. The signal output terminal of the energy storage battery is set as the detection point of the energy storage battery. The signal input terminal of the detection circuit is connected to the detection point to collect the voltage, current and temperature of the energy storage battery. The control circuit uses an STM32F103 series or GD32 series main control chip. The power input terminal of the control circuit is electrically connected to the power output terminal of the energy storage battery; the signal input terminal of the control circuit is connected to the signal output terminal of the detection circuit, used to send the acquired digital signals from the detection circuit to the control circuit; the control circuit is bidirectionally connected to the MPPT controller, used to send tracking start / stop commands to the MPPT controller and to receive the operating status of the MPPT controller; the signal output terminal of the control circuit is connected to the signal input terminal of the energy storage battery, used to obtain information such as the battery charge and health status.

[0032] The irrigation equipment uses a DC irrigation water pump, and the power input terminal of the irrigation equipment is electrically connected to the power output terminal of the energy storage battery; the control circuit starts and stops the irrigation equipment by cutting off the power supply from the energy storage battery to the irrigation equipment, thus the irrigation equipment is controlled by the control circuit.

[0033] In a preferred embodiment, as shown in the appendix Figure 1 Appendix Figure 2 As shown, the MPPT controller, energy storage battery, detection circuit, and control circuit are integrated into a portable component, and the connection interface between the photovoltaic module and the irrigation equipment is located on the outer shell of the portable component.

[0034] The working principle of this invention is as follows: During periods of ample sunlight, the photovoltaic modules generate direct current (DC). After confirming the power input, the MPPT controller performs maximum power point tracking and charges the energy storage battery via a DC / DC circuit. The detection circuit reports the electrical parameters of the photovoltaic system and the battery to the control circuit in real time. When the battery voltage reaches the full charge threshold of 54.6V or the temperature exceeds 60°C, the control circuit immediately enters protection mode, cutting off the charging circuit and locking the system to prevent overcharging or overheating. Once the battery voltage drops or the temperature decreases, the circuit automatically unlocks and resumes charging.

[0035] When irrigation is needed, the user presses the start button. The control circuit first checks if the system is in a protection lockout state. If not locked, it sends a start signal to the irrigation equipment, and the energy storage battery directly drives the irrigation pump through the DC output interface. During irrigation, the control circuit continuously monitors the battery status, and immediately stops irrigation and enters protection mode if any abnormality occurs.

[0036] When there is no light and the system is idle, the control circuit automatically enters a low-power standby mode, waking up every 30 seconds to detect the light conditions so that it can automatically resume charging the next morning.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control method for an irrigation system, characterized in that, Includes the following steps: S1: Determine if the photovoltaic module is outputting electrical energy; If so, execute S2; S2: Based on the detected output voltage and output current of the photovoltaic module, the MPPT controller performs maximum power point tracking control, calculates the current power point, and performs buck / boost voltage regulation by adjusting the duty cycle of the DC / DC circuit inside the MPPT controller; at the same time, based on the detected battery voltage and battery temperature of the energy storage battery, a feedback signal is generated and applied to the maximum power point tracking control and the duty cycle adjustment of the DC / DC circuit; S3: Perform safety monitoring on the energy storage battery, including battery voltage, battery temperature, charging current and / or state of charge. If the monitoring results are normal, control the energy storage battery to charge, and then execute S4; If the monitoring results are abnormal, including overvoltage, overtemperature, overcurrent and / or state of charge exceeding the limit, the protection mode is entered: the charging circuit is cut off, the maximum power point tracking control is suspended, the system is locked to prevent the energy storage battery from discharging, and then it returns to S1. S4: Determine if the energy storage battery is fully charged; If not fully filled, return to S1; If fully charged, the control circuit returns a full charge signal, disconnects the main charging circuit, and charging ends. S5: When an irrigation command is received and the system is not in a protected lockout state, the control circuit controls whether the energy storage battery supplies power to the irrigation equipment, thereby controlling the start and stop of the irrigation equipment.

2. The control method for an irrigation system according to claim 1, characterized in that: In S2, the output voltage and output current of the photovoltaic module are collected by the MPPT controller, and maximum power point tracking control is performed, as well as the current power point is calculated; in S2 and S3, the detection data of the energy storage battery are collected by the detection circuit and provided to the control circuit.

3. The control method for an irrigation system according to claim 1, characterized in that: The maximum power point tracking control employs a perturbation-observation method, which tracks the maximum power point by periodically perturbing the duty cycle of the DC / DC circuit and observing the changes in the output power of the photovoltaic module.

4. The control method for an irrigation system according to claim 1, characterized in that, In S3, the overvoltage threshold for the safety monitoring energy storage battery voltage is set to 1.05 times the rated voltage of the energy storage battery, and the overtemperature threshold for the energy storage battery temperature is set to 60°C.

5. The control method for an irrigation system according to claim 1, characterized in that: The feedback signal is used to correct the tracking direction of the MPPT control and / or correct the duty cycle adjustment step size of the DC / DC circuit.

6. An irrigation system implementing the control method according to any one of claims 1-5, characterized in that: include: Photovoltaic modules; MPPT controller, wherein the power input terminal of the MPPT controller is electrically connected to the power output terminal of the photovoltaic module; An energy storage battery, wherein the power input terminal of the energy storage battery is electrically connected to the power output terminal of the MPPT controller; The detection circuit has its power input terminal electrically connected to the power output terminal of the energy storage battery, and its signal input terminal connected to the signal output terminal of the energy storage battery. The control circuit has its power input terminal electrically connected to the power output terminal of the energy storage battery; its signal input terminal is signal-connected to the signal output terminal of the detection circuit; the control circuit is bidirectionally signal-connected to the MPPT controller; and its signal output terminal is signal-connected to the signal input terminal of the energy storage battery. An irrigation device, wherein the power input terminal of the irrigation device is electrically connected to the power output terminal of the energy storage battery.

7. An irrigation system according to claim 6, characterized in that: The MPPT controller integrates a DC / DC circuit, which adopts a Buck topology, a Boost topology, or a Buck-Boost topology.

8. An irrigation system according to claim 6, characterized in that: The power input terminal of the MPPT controller is electrically connected to the power output terminal of the photovoltaic module to collect the output voltage and output current of the photovoltaic module; the signal output terminal of the energy storage battery is set as the detection point of the energy storage battery; the signal input terminal of the detection circuit is connected to the detection point to collect the voltage, current and temperature of the energy storage battery.

9. An irrigation system according to claim 6, characterized in that: The control circuit uses an STM32 series or GD32 series main control chip.

10. An irrigation system according to claim 6, characterized in that: The MPPT controller, the energy storage battery, the detection circuit, and the control circuit are integrated into a portable component, and the connection interface between the photovoltaic module and the irrigation equipment is located on the outer shell of the portable component.

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