A method and system for multi-source coordinated scheduling and control of photovoltaic water pumps.

Abstract

This application relates to the field of photovoltaic water pump control technology, and particularly to a multi-source coordinated scheduling and control method and system for photovoltaic water pumps. The method includes: comparing the output power of the photovoltaic array with the required power; when the output power of the photovoltaic array is greater than the required power, the frequency converter determines whether to supplement the energy storage module; when the output power of the photovoltaic array is less than the required power, the frequency converter outputs the energy from the energy storage module to the water pump via a DC / DC module, and when the energy storage module can no longer provide energy, the frequency converter controls grid connection; when the output power of the photovoltaic array is less than a preset lower limit power, and the energy storage module cannot output energy to the water pump via the DC / DC module, and cannot be connected to the grid, the frequency converter stores the energy of the photovoltaic array in reverse to the energy storage module via the DC / DC module. This application helps overcome the problems of energy loss, unusable low-power areas, and frequent grid switching in existing photovoltaic water pump systems.

Description

Technical Field

[0001] This application relates to the field of photovoltaic water pump control technology, and in particular to a method and system for multi-source coordinated scheduling and control of photovoltaic water pumps. Background Technology

[0002] Currently, photovoltaic water pump systems typically consist of photovoltaic arrays, frequency converters, water pumps, and grid power supplies, and are widely used in agricultural irrigation, water supply in remote areas, and ecological restoration.

[0003] However, the output power of photovoltaic arrays is greatly affected by weather conditions, exhibiting significant intermittency and fluctuation. When sunlight suddenly intensifies or weakens, the system is prone to energy waste or pump shutdown due to insufficient power. Especially when the output power of the photovoltaic array is low, existing systems often cannot effectively utilize this energy. There are two common solutions: one is to increase the installed capacity of the photovoltaic array to make up for the energy gap during low power periods, but this method significantly increases system costs; the other is to directly abandon the energy in the low-power area, resulting in low utilization efficiency of the photovoltaic array.

[0004] Furthermore, in systems employing a hybrid photovoltaic (PV) and grid power supply, when PV power is insufficient to meet load demands, the system frequently switches to grid power; conversely, when PV power recovers, it needs to switch back to PV power. This frequent switching not only affects the stability of water pump operation but also impacts the power grid, reduces power quality, and shortens the lifespan of electrical switching equipment.

[0005] Therefore, overcoming the problems of energy loss, inability to utilize low-power areas, and frequent grid switching in existing photovoltaic water pump systems is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] Therefore, it is necessary to provide a method and system for multi-source coordinated scheduling and control of photovoltaic water pumps that can overcome the problems of energy loss, unusable low-power areas, and frequent grid switching in existing photovoltaic water pump systems.

[0007] In a first aspect, this application provides a method for multi-source coordinated scheduling and control of photovoltaic water pumps, the method comprising: The output power of the photovoltaic array and the power demand of the water pump are obtained from the real-time monitoring of the frequency converter, and the output power of the photovoltaic array is compared with the power demand. When the output power of the photovoltaic array is greater than the required power, the frequency converter determines whether to replenish the energy storage component based on the voltage status of the energy storage component. When the output power of the photovoltaic array is less than the required power, the frequency converter outputs the energy of the energy storage component to the water pump via the DC / DC module according to the voltage status of the energy storage component. When the energy storage component can no longer provide energy, the frequency converter controls the grid connection to ensure the water pump output. When the output power of the photovoltaic array is less than the preset lower limit power, and the energy storage component cannot output energy to the water pump through the DC / DC module, and cannot be connected to the power grid, the frequency converter will reverse the energy of the photovoltaic array to the energy storage component through the DC / DC module.

[0008] In one embodiment, determining whether to replenish the energy storage component based on its voltage state includes: Determine whether the voltage of the energy storage component is lower than a first preset threshold. If so, determine that the energy storage component needs to be replenished, and prioritize replenishing the energy storage component with excess power from the photovoltaic array via a DC / DC module. If the voltage of the energy storage component is higher than a second preset threshold, the energy storage component is determined to be in an energy saturation state, and the pump speed is actively increased to convert excess electrical energy into mechanical energy.

[0009] In one embodiment, the energy from the energy storage component is output to the water pump via a DC / DC module based on the voltage state of the energy storage component. When the energy storage component can no longer provide energy, the frequency converter controls the grid connection to ensure that the water pump's output includes: If the voltage of the energy storage component is higher than a third preset threshold, the energy storage component is determined to be in a dischargeable state, and the energy of the energy storage component is output to the water pump via a DC / DC module to compensate for the insufficient output power of the photovoltaic array and ensure the water output of the water pump. When the voltage of the energy storage component is lower than the fourth preset threshold, it is determined that the energy storage component can no longer provide energy. The frequency converter actively controls the grid connection, and the grid supplies power to the water pump to reduce the frequent switching of the grid and further ensure the water output of the water pump.

[0010] In one embodiment, the step of determining whether the voltage of the energy storage component is higher than a third preset threshold is performed. If so, the energy storage component is determined to be in a dischargeable state, and the energy of the energy storage component is output to the water pump via a DC / DC module to compensate for the insufficient output power of the photovoltaic array, ensuring that the water pump output includes: The voltage of the energy storage component is collected in real time, and it is determined whether the voltage of the energy storage component is higher than a third preset threshold. The third preset threshold is corrected online based on the health status of the energy storage component and the ambient temperature. When the voltage of the energy storage component is higher than the third preset threshold, it is determined that the energy storage component is in a dischargeable state, and the real-time power difference between the required power and the output power of the photovoltaic array is calculated. The real-time power difference is used as the power to be compensated. At the same time, a first-order low-pass filter is introduced to smooth the real-time power difference to obtain a smooth compensation power command, so as to filter out the high-frequency fluctuations of the output power of the photovoltaic array. According to the smooth compensation power command, the DC / DC module is controlled to output the energy of the energy storage component to the water pump at a preset power rate, so that the actual input power of the water pump is equal to or close to the required power, in order to compensate for the insufficient output power of the photovoltaic array and ensure the water output of the water pump.

[0011] In one embodiment, the photovoltaic water pump multi-source coordinated scheduling and control method further includes: During the compensation process, the change trend of the photovoltaic array output power is continuously monitored. If it is predicted that the output power of the photovoltaic array will rise rapidly within a preset time window and will soon exceed the required power, the energy output power of the energy storage component will be reduced in advance to achieve a seamless and smooth transition between photovoltaic output and energy storage discharge, and to prevent overcompensation and energy waste.

[0012] In one embodiment, when the voltage of the energy storage component is lower than a fourth preset threshold, it is determined that the energy storage component can no longer provide energy. The frequency converter actively controls the grid connection, and the grid supplies power to the water pump to reduce frequent grid switching and further ensure that the water pump's output includes: The voltage of the energy storage component is monitored in real time. When the voltage of the energy storage component is lower than the fourth preset threshold, it is determined that the energy storage component can no longer provide energy and a grid connection request is generated. In response to the grid connection request, the frequency converter synchronously detects the voltage, frequency and phase of the grid side, and controls the bidirectional AC / DC module to perform soft start, gradually increasing the grid output power from zero to the power required by the water pump at a preset power ramp rate; After the power grid is connected to supply power to the water pump, if the voltage of the energy storage component is detected to rise above the fifth preset threshold, or the output power of the photovoltaic array rises to a preset ratio that can independently meet the water pump's needs, the frequency converter actively controls the power grid to gradually disconnect at the same power ramp rate, achieving seamless disconnection from the power grid, reducing frequent grid switching, and further ensuring the water pump's output.

[0013] In one embodiment, the step of storing the energy of the photovoltaic array in reverse via a DC / DC module to the energy storage component includes: Based on the real-time collected photovoltaic array output power, energy storage component voltage, and ambient temperature, the maximum allowable charging power and charging current threshold of the energy storage component are calculated. The inverter combines the output power of the photovoltaic array, the maximum charging power, and the charging current threshold to generate a charging power command, which controls the DC / DC module to establish a charging circuit and store the energy of the photovoltaic array in reverse to the energy storage component.

[0014] In one embodiment, the photovoltaic water pump multi-source coordinated scheduling and control method further includes: During the reverse storage process, the voltage, charging current, and cell temperature of the energy storage component are continuously monitored. When the voltage, charging current, and cell temperature of the energy storage component exceed the preset safety range, the output power of the DC / DC module is dynamically reduced based on the maximum charging power threshold and the charging current threshold. When the voltage of the energy storage component reaches the second preset threshold, or when the energy of the photovoltaic array can meet the needs of the water pump, the charging circuit is gradually shut down.

[0015] Secondly, this application also provides a photovoltaic water pump multi-source coordinated scheduling and control system, the system including a photovoltaic array, energy storage components, a frequency converter, a DC / DC module and a power grid; The photovoltaic array is used to convert solar energy into direct current (DC) electricity. The energy storage component is used to store electrical energy and provide supplemental energy to the water pump; The DC / DC module is connected to the photovoltaic array, the energy storage component and the frequency converter respectively, and is used to realize energy transmission; The frequency converter is connected to the photovoltaic array, the energy storage component, the DC / DC module and the power grid respectively. The frequency converter has a built-in control unit for real-time monitoring of the output power of the photovoltaic array, the voltage status of the energy storage component and the status of the power grid, and for performing power comparison, energy storage charging and discharging control, water pump speed adjustment and power grid access control.

[0016] In summary, this application includes the following beneficial technical effects: By acquiring and comparing the output power of the photovoltaic array with the power demand of the water pump in real time, the system's energy supply and demand relationship can be accurately determined, providing a decision-making basis for subsequent multi-source coordinated scheduling and avoiding blind switching or energy waste. When the output power of the photovoltaic array is greater than the demand power, the frequency converter decides whether to supplement the energy based on the voltage status of the energy storage components, which can effectively avoid energy loss and improve the utilization rate of photovoltaic power generation. When the output power of the photovoltaic array is less than the demand power, the frequency converter prioritizes the use of the energy storage components to supplement the power of the water pump through the DC / DC module, ensuring a stable water output. When the energy storage can no longer supply power, the frequency converter actively controls the grid connection, and the grid supplies power to the water pump. This not only avoids water pump shutdown due to insufficient power, but also significantly reduces the impact of frequent grid on / off cycles through the active switching strategy, extending equipment life and improving power quality. When the photovoltaic power is insufficient, the energy storage cannot discharge, and the grid cannot be connected, the frequency converter reverses the energy output of the photovoltaic array to the energy storage components, allowing the energy in the previously unusable low-power photovoltaic area to be recovered, further improving the system's all-weather energy utilization efficiency. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the multi-source coordinated scheduling and control method of photovoltaic water pumps in one embodiment; Figure 2 This is a structural block diagram of a photovoltaic water pump multi-source collaborative scheduling and control device in one embodiment. Detailed Implementation

[0018] This invention provides a method and system for multi-source coordinated scheduling and control of photovoltaic water pumps.

[0019] The embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0020] In the description of the embodiments disclosed in this invention, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0021] For ease of understanding, the specific process of the embodiments of the present invention is described below. Please refer to [link / reference]. Figure 1 One embodiment of the photovoltaic water pump multi-source coordinated scheduling and control method in this invention includes: S100 acquires the photovoltaic array output power and water pump demand power monitored in real time by the frequency converter, and compares the photovoltaic array output power with the demand power.

[0022] Specifically, the inverter first collects the output power of the photovoltaic array and the power demand of the water pump in real time. The control unit inside the inverter obtains the DC-side power of the photovoltaic array through voltage and current sensors, and calculates the power demand of the water pump based on parameters such as the set speed, head, and flow rate of the water pump. Subsequently, the inverter compares the collected output power of the photovoltaic array with the power demand of the water pump to determine the relationship between the two. The comparison result provides a decision-making basis for subsequent multi-source energy dispatch: if the photovoltaic power is greater than the power demand, it indicates that there is surplus electrical energy available for use; if the photovoltaic power is less than the power demand, it indicates that the current photovoltaic power generation capacity is insufficient to independently drive the water pump, and it is necessary to supplement it from other energy sources.

[0023] S200: When the output power of the photovoltaic array is greater than the required power, the frequency converter determines whether to supplement the energy storage component based on the voltage status of the energy storage component.

[0024] Specifically, when the inverter determines that the output power of the photovoltaic array is greater than the power required by the water pump, it indicates that there is surplus photovoltaic energy. At this time, the inverter further detects the voltage status of the energy storage module and determines whether it needs to be recharged based on the voltage status. Specifically, the inverter obtains the voltage of the energy storage module (e.g., battery pack) through a voltage sampling circuit. If the voltage reflects that the energy storage module is currently low in charge and not yet saturated, the inverter determines that recharging is needed and transmits the excess electrical energy from the photovoltaic array to the energy storage module through the DC / DC module to achieve energy storage. Conversely, if the voltage reflects that the energy storage module is already at a high charge or saturated, the inverter determines that recharging is not needed and instead distributes the excess energy to the water pump or other loads to maintain the energy balance of the system. This avoids the waste of photovoltaic energy and prevents the risk of overcharging of the energy storage module.

[0025] S300: When the output power of the photovoltaic array is less than the required power, the frequency converter outputs the energy of the energy storage component to the water pump through the DC / DC module according to the voltage status of the energy storage component. When the energy storage component can no longer provide energy, the frequency converter controls the grid connection to ensure the water pump output.

[0026] Specifically, when the inverter determines that the output power of the photovoltaic array is less than the power required by the water pump, it indicates that the photovoltaic power generation is insufficient to support the operation of the water pump alone. In this case, the inverter first checks the voltage status of the energy storage module. If the voltage is within the discharge range (i.e., the energy storage module still has residual energy), the inverter controls the DC / DC module to release the electrical energy stored in the energy storage module. After conversion by the DC / DC module, the energy is delivered to the water pump, working together with the electrical energy output from the photovoltaic array to power the water pump, compensating for the insufficient photovoltaic power and ensuring a stable water output. During the discharge process of the energy storage module, the inverter continuously monitors its voltage changes. Once it detects that the voltage of the energy storage module has dropped to a level where it can no longer effectively output energy (i.e., the energy storage module is depleted or the voltage is too low), the inverter automatically controls the grid connection circuit, allowing the grid to provide the required electrical energy to the water pump. In this way, when the power demand of the water pump cannot be met by photovoltaics and energy storage, the grid can be put into operation in a timely manner, avoiding the water pump from shutting down or reducing the water output due to insufficient power, thus ensuring the continuity of water supply. At the same time, the frequent switching of the grid is reduced through active control.

[0027] S400: When the output power of the photovoltaic array is less than the preset lower limit power, and the energy storage component cannot output energy to the water pump through the DC / DC module, and cannot be connected to the grid, the frequency converter will reverse the energy of the photovoltaic array to the energy storage component through the DC / DC module.

[0028] Specifically, when the output power of the photovoltaic array is less than the preset lower limit, if the inverter determines that the energy storage module can no longer output energy to the water pump through the DC / DC module (e.g., the energy storage module voltage is too low, the power is exhausted, or a fault protection has occurred), and at the same time the grid cannot be connected (e.g., grid outage, line fault), the inverter will adjust its control strategy. It will no longer attempt to obtain energy from the energy storage or the grid, but instead will transmit the limited energy currently output by the photovoltaic array in reverse through the DC / DC module to the energy storage module. In other words, although the photovoltaic power is insufficient to drive the water pump, this energy is not wasted but stored in the energy storage module. This avoids the waste of photovoltaic energy in the low-power area and gradually replenishes the energy storage module. Once the energy storage module recovers some energy, it can support the water pump when needed again. This process achieves effective recovery and utilization of photovoltaic energy in the low-power area under extreme conditions, improving the system's overall energy utilization efficiency throughout the day.

[0029] In one embodiment, determining whether to replenish the energy storage module based on its voltage state includes: If the voltage of the energy storage component is lower than the first preset threshold, it is determined that the energy storage component needs to be replenished, and the excess power of the photovoltaic array is used to replenish the energy storage component via the DC / DC module. If the voltage of the energy storage component is higher than the second preset threshold, it is determined that the energy storage component is in an energy saturation state, and the pump speed is actively increased to convert the excess power into mechanical power.

[0030] Specifically, when the output power of the photovoltaic array exceeds the power demand of the water pump, the frequency converter further judges the voltage status of the energy storage module. Specifically, the frequency converter has a preset first threshold, which corresponds to the minimum voltage boundary at which the energy storage module needs to be replenished. The frequency converter obtains the voltage of the energy storage module in real time through a voltage sampling circuit and compares this voltage with the first preset threshold. When the voltage of the energy storage module is detected to be lower than the first preset threshold, the frequency converter determines that the current energy storage module is in a state of insufficient power and needs to be replenished. Under this determination, the frequency converter executes a priority replenishment strategy: it prioritizes the allocation of excess power output from the photovoltaic array to the energy storage module, establishes a charging circuit by controlling the DC / DC module, and delivers the excess power to the energy storage module after conversion by the DC / DC module to charge the energy storage module. In this way, the system can prioritize replenishing the energy storage module's power when photovoltaic energy is abundant, thereby avoiding the energy storage module being in a state of undervoltage for a long time and laying the foundation for discharge backup when photovoltaic power is insufficient.

[0031] While the inverter determines that the output power of the photovoltaic array exceeds the power demand of the water pump and that there is excess electrical energy, it also checks whether the voltage of the energy storage module is higher than a second preset threshold. This second preset threshold is the upper limit voltage value representing the energy saturation of the energy storage module, and its value is higher than the aforementioned first preset threshold. When the inverter detects that the voltage of the energy storage module is higher than the second preset threshold, it determines that the energy storage module is in an energy saturation state, meaning its charge is full and it is no longer suitable to continue charging. In this case, the inverter no longer uses the excess electrical energy for recharging. Instead, it actively increases the speed of the water pump. By increasing the pump's speed, it consumes more mechanical energy, thereby converting the excess electrical energy output by the photovoltaic array into the mechanical energy of the water pump, storing or utilizing it in the form of water's potential or kinetic energy. This avoids both the curtailment of photovoltaic energy and the risk of overcharging due to continuous charging of the already saturated energy storage module, achieving effective utilization of excess energy.

[0032] In one embodiment, based on the voltage state of the energy storage component, the energy from the energy storage component is output to the water pump via a DC / DC module. When the energy storage component can no longer provide energy, the frequency converter controls the grid connection to ensure that the water pump's output includes: If the voltage of the energy storage component is higher than the third preset threshold, the energy storage component is determined to be in a dischargeable state, and the energy of the energy storage component is output to the water pump through the DC / DC module to compensate for the insufficient output power of the photovoltaic array and ensure the water output of the water pump. If the voltage of the energy storage component is lower than the fourth preset threshold, the energy storage component is determined to be unable to continue to provide energy, and the frequency converter actively controls the grid connection to supply power to the water pump, thereby reducing the frequent switching of the grid and further ensuring the water output of the water pump.

[0033] Specifically, when the output power of the photovoltaic array is less than the power required by the water pump, the frequency converter controls the energy storage to discharge or connect to the grid based on the voltage status of the energy storage component. Specifically, the frequency converter has a third preset threshold and a fourth preset threshold. The third preset threshold determines whether the energy storage component has the ability to discharge, and the fourth preset threshold determines whether the energy storage component can no longer provide energy. The frequency converter monitors the voltage of the energy storage component in real time and compares it with the third preset threshold. When the voltage of the energy storage component is higher than the third preset threshold, the frequency converter determines that the energy storage component is in a dischargeable state and then controls the DC / DC module to output the energy stored in the energy storage component to the water pump to compensate for the insufficient output power of the photovoltaic array, thereby ensuring a stable water output. Simultaneously, the frequency converter continuously monitors the voltage changes of the energy storage component. When it detects that the voltage of the energy storage component is lower than the fourth preset threshold, the frequency converter determines that the energy storage component can no longer provide effective energy to the water pump. At this time, the frequency converter actively controls the grid connection, and the grid supplies power to the water pump. In this way, the system prioritizes using energy storage to make up for the photovoltaic power gap, and seamlessly switches to grid power after the energy storage is depleted. This not only ensures the continuity of water pump output, but also reduces unnecessary frequent switching through proactive grid connection strategies, thereby improving the stability of system operation.

[0034] In one embodiment, it is determined whether the voltage of the energy storage component is higher than a third preset threshold. If so, the energy storage component is determined to be in a dischargeable state, and the energy of the energy storage component is output to the water pump via a DC / DC module to compensate for the insufficient output power of the photovoltaic array, ensuring that the water pump output includes: The voltage of the energy storage module is collected in real time to determine whether it exceeds a third preset threshold. This third preset threshold is adjusted online based on the health status of the energy storage module and the ambient temperature. When the voltage of the energy storage module exceeds the third preset threshold, it is determined that the energy storage module is in a dischargeable state. The real-time power difference between the required power and the output power of the photovoltaic array is calculated and used as the power to be compensated. Simultaneously, a first-order low-pass filter is introduced to smooth the real-time power difference, resulting in a smooth compensation power command to filter out high-frequency fluctuations in the output power of the photovoltaic array. Based on the smooth compensation power command, the DC / DC module is controlled to output the energy of the energy storage module to the water pump at a preset power rate, so that the actual input power of the water pump is equal to or close to the required power, thereby compensating for the insufficient output power of the photovoltaic array and ensuring the water output of the pump.

[0035] Specifically, firstly, the inverter collects the voltage of the energy storage module in real time at a high sampling rate and compares this voltage with a third preset threshold. It's important to note that this third preset threshold is not a fixed value, but rather dynamically corrects itself online based on the health status of the energy storage module (i.e., the degree of aging such as capacity decay and increased internal resistance as the energy storage module increases with usage) and the current ambient temperature (temperature significantly affects the battery's discharge capacity; the discharge voltage threshold needs to be adjusted accordingly at low temperatures). This ensures accurate determination of the energy storage module's true discharge capacity under different usage stages and environmental conditions. When the inverter determines that the energy storage module's voltage is higher than the third preset threshold, it confirms that the energy storage module has the ability to output energy to the water pump. Subsequently, the inverter calculates the real-time power difference between the water pump's required power and the current output power of the photovoltaic array. This difference represents the power missing to maintain a stable water output from the pump and is used as the power value to be compensated. Considering that the output power of photovoltaic arrays is affected by factors such as sunlight intensity and cloud cover, often containing high-frequency random fluctuations, directly using this instantaneous power difference as a compensation command to control energy storage discharge could easily cause drastic jumps in the water pump's input power, leading to pump instability or even mechanical shock. Therefore, the inverter introduces a first-order low-pass filter to smooth this real-time power difference. This filter effectively filters out high-frequency fluctuations in the photovoltaic power, retaining only a relatively gentle power change trend, thus generating a stable and continuous smooth compensation power command. After obtaining the smooth compensation power command, the inverter controls the DC / DC module according to this command. Specifically, the inverter internally presets a power change rate (e.g., the allowed increase or decrease in power per second). The DC / DC module gradually outputs energy from the energy storage components to the water pump according to this preset power rate, allowing the energy storage discharge power to slowly and smoothly follow the changes in the smooth compensation power command. In this way, the actual input power of the water pump (i.e., the sum of the photovoltaic output power and the energy storage discharge power) is controlled at a level equal to or very close to the required power. Ultimately, even if the output power of the photovoltaic array fluctuates or is insufficient, the water pump can still obtain a stable power supply, and its water output is reliably guaranteed. Throughout the process, because the compensation command is smoothed and the discharge power rises or falls at a preset rate, the impact of sudden changes in energy storage discharge on power electronic devices and water pump mechanical systems is avoided, achieving flexible and precise compensation of photovoltaic power gaps by energy storage.

[0036] In one embodiment, the photovoltaic water pump multi-source coordinated scheduling and control method further includes: During the compensation process, the changing trend of the photovoltaic array output power is continuously monitored. If it is predicted that the output power of the photovoltaic array will rise rapidly within the preset time window and will soon exceed the required power, the energy output power of the energy storage component will be reduced in advance to achieve a seamless and smooth transition between photovoltaic output and energy storage discharge, and to prevent overcompensation and energy waste.

[0037] Specifically, the frequency converter collects time-series data on the output power of the photovoltaic array. By analyzing its rate of change and fluctuation characteristics, it predicts whether the output power of the photovoltaic array will rise rapidly within a preset time window and determines whether this rise will cause the photovoltaic power to exceed the power demand of the water pump. If it is predicted that the photovoltaic power will shift from insufficient to excessive within the upcoming time window, and the excess will be significant, the frequency converter proactively reduces the energy output power of the energy storage components before the photovoltaic power actually exceeds the demand power. This proactive reduction does not wait until the photovoltaic power has already exceeded the demand power before adjusting; instead, it reduces the energy storage discharge power in advance during the rapid rise of photovoltaic power, ensuring that the gradual increase in photovoltaic power and the gradual decrease in energy storage discharge power are time-coordinated. Through this predictive feedforward control, when the photovoltaic power rises to exactly equal to or slightly higher than the demand power, the energy storage discharge power has synchronously decreased to zero or a very small value, thus achieving a seamless and smooth transition between photovoltaic output and energy storage discharge.

[0038] In one embodiment, when the voltage of the energy storage component falls below a fourth preset threshold, it is determined that the energy storage component can no longer provide energy. The frequency converter actively controls the grid connection, and the grid supplies power to the water pump to reduce frequent grid switching and further ensure that the water pump's output includes: The voltage of the energy storage module is monitored in real time. When the voltage of the energy storage module is lower than the fourth preset threshold, it is determined that the energy storage module can no longer provide energy and a grid connection request is generated. In response to the grid connection request, the frequency converter synchronously detects the voltage, frequency and phase of the grid side and controls the bidirectional AC / DC module to perform soft start, gradually increasing the grid output power from zero to the power required by the water pump at a preset power ramp rate. After the grid connects to supply power to the water pump, if the voltage of the energy storage module is detected to rise above the fifth preset threshold, or the output power of the photovoltaic array rises to a preset proportion that can independently meet the water pump's needs, the frequency converter actively controls the grid to gradually disconnect at the same power ramp rate, achieving seamless grid disconnection, reducing frequent grid switching, and further ensuring the water pump's output.

[0039] Specifically, after the frequency converter determines that the voltage of the energy storage component is lower than the fourth preset threshold, thus confirming that the energy storage component can no longer provide energy to the water pump, the system executes the grid connection control process. First, the frequency converter generates a grid connection request and, in response to the request, synchronously detects the voltage amplitude, frequency, and phase on the grid side to ensure that the electrical parameters of the frequency converter and the grid match, avoiding the large current surge caused by direct closing. Subsequently, the frequency converter controls the bidirectional AC / DC module to perform a soft-start operation, that is, instead of directly connecting the grid to full power, it gradually increases the active power output of the grid from zero according to a preset power ramp rate until it reaches the power required by the water pump. Through this soft-start and power ramp-up method, grid energy is smoothly injected into the DC bus to power the water pump, avoiding the impact of power surges on the grid and the power electronic devices inside the frequency converter. During operation with the grid connected and supplying power to the water pump, the frequency converter continues to monitor the voltage status of the energy storage components and the output power of the photovoltaic array. When the voltage of the energy storage components rises above the fifth preset threshold (this threshold is higher than the fourth preset threshold, indicating that the energy storage components have recovered a certain amount of power), or when the output power of the photovoltaic array rises to a preset percentage sufficient to independently meet the water pump's needs (e.g., 80% or 100%, indicating that the photovoltaic power is sufficient to support the water pump's operation), the frequency converter actively controls grid disconnection. The grid disconnection process also uses the same power ramp-up rate as during connection, i.e., controlling the bidirectional AC / DC module to gradually reduce the grid output power to zero at this rate, thereby achieving seamless grid disconnection. Through this power control strategy of gradual ramp-up and ramp-down during both connection and disconnection, the system effectively reduces the impact of frequent grid switching, avoids voltage flicker and frequency fluctuations caused by power surges, and further ensures the continuity of water pump output and the operational reliability of the system's electrical equipment.

[0040] In one embodiment, storing the energy of the photovoltaic array in reverse via a DC / DC module to an energy storage component includes: Based on the real-time collected photovoltaic array output power, energy storage component voltage, and ambient temperature, the maximum allowable charging power and charging current threshold of the energy storage component are calculated. The frequency converter combines the photovoltaic array output power, maximum charging power, and charging current threshold to generate a charging power command, control the DC / DC module to establish a charging circuit, and store the energy of the photovoltaic array in reverse to the energy storage component.

[0041] Specifically, when the output power of the photovoltaic array is less than the preset lower limit, the energy storage module cannot output energy to the water pump via the DC / DC module, and the power grid cannot be connected, the frequency converter executes reverse storage control, storing the energy of the photovoltaic array into the energy storage module via the DC / DC module. During this reverse storage process, the frequency converter first calculates based on several parameters collected in real time: including the current output power of the photovoltaic array, the voltage of the energy storage module, and the ambient temperature. Based on these parameters, the frequency converter calculates the maximum allowable charging power and charging current threshold of the energy storage module under the current state using a built-in algorithm or lookup table model. This maximum charging power and charging current threshold consider the influence of the energy storage module's chemical characteristics, internal resistance, and temperature on its charging acceptance capability, aiming to prevent excessive charging power or current from damaging the energy storage module. Subsequently, the frequency converter comprehensively considers the actual output power that the photovoltaic array can provide, the calculated maximum charging power, and the charging current threshold to generate a charging power command. This charging power command does not change abruptly but undergoes appropriate smoothing processing, ensuring that the rate of change of charging power is within the range that the energy storage module can withstand. According to the charging power command, the inverter controls the DC / DC module to establish a charging circuit, converting the electrical energy output from the photovoltaic array into electricity and then smoothly storing it in the energy storage module. Through this method, the system can effectively recover energy from low-power photovoltaic areas under extreme conditions, while ensuring the charging process of the energy storage module is safe and controllable, avoiding overcharging, overheating, or lifespan degradation caused by charging power or current exceeding allowable limits.

[0042] In one embodiment, the photovoltaic water pump multi-source coordinated scheduling and control method further includes: During the reverse storage process, the voltage, charging current, and cell temperature of the energy storage component are continuously monitored. When the voltage, charging current, and cell temperature of the energy storage component exceed the preset safe range, the output power of the DC / DC module is dynamically reduced based on the maximum charging power threshold and the charging current threshold. When the voltage of the energy storage component reaches the second preset threshold, or when the energy of the photovoltaic array can meet the needs of the water pump, the charging circuit is gradually shut down.

[0043] Specifically, during reverse storage, the inverter continuously monitors the voltage, charging current, and cell temperature of the energy storage components to ensure that the charging process remains safe and controllable. Specifically, the inverter has preset safety ranges corresponding to these voltage, charging current, and cell temperature. When the inverter detects that any one of these parameters exceeds the corresponding preset safety range, the system immediately initiates a safety protection response. This response does not simply shut down the charging circuit; instead, it dynamically adjusts the output power of the DC / DC module downwards based on the maximum allowable charging power and current thresholds of the current energy storage components. This gradually reduces the charging power and current, bringing them back within the safe range. This dynamic adjustment, rather than a sudden cutoff, protects the energy storage components from overcharging, overcurrent, or high-temperature damage, while also avoiding voltage spikes or energy waste that could result from a sudden interruption of the charging circuit. Meanwhile, the inverter continuously determines the termination conditions of the reverse storage process. When the voltage of the energy storage module rises to the second preset threshold (indicating that the energy storage module is in an energy saturation state), or when the output power of the photovoltaic array recovers to the point where it can independently meet the water pump's needs (i.e., there is no longer a need to store photovoltaic energy, but rather to prioritize supplying the water pump), the inverter stops reverse storage and actively executes a gradual shutdown of the charging circuit, causing the charging power to decrease to zero at a smooth rate, and finally completely shutting down the charging circuit. Through the above-mentioned control strategy of continuous monitoring, dynamic adjustment, and gradual shutdown, the system ensures the charging safety and lifespan of the energy storage module while recovering energy in the low-power area of ​​the photovoltaic system, and achieves a smooth transition from the charging state to other operating modes.

[0044] In one embodiment, such as Figure 2 As shown, a photovoltaic water pump multi-source coordinated scheduling and control system is provided, including a photovoltaic array, energy storage components, frequency converter, DC / DC module and power grid; Photovoltaic arrays are used to convert solar energy into direct current (DC) electricity. Energy storage components are used to store electrical energy and provide supplemental energy for water pumps; The DC / DC module is connected to the photovoltaic array, energy storage components and frequency converter respectively to realize energy transmission; The frequency converter is connected to the photovoltaic array, energy storage components, DC / DC module and power grid respectively. The frequency converter has a built-in control unit for real-time monitoring of the output power of the photovoltaic array, the voltage status of the energy storage components and the status of the power grid, and performs power comparison, energy storage charging and discharging control, water pump speed regulation and power grid connection control.

[0045] Specifically, the system includes a photovoltaic array, energy storage components, a frequency converter, a DC / DC module, and a power grid. The photovoltaic array receives solar energy and converts it into DC power, serving as the system's primary energy source. The energy storage components store excess energy when photovoltaic energy is abundant and release it when photovoltaic energy is insufficient, providing supplementary energy for the water pump and acting as a buffer and regulator. The DC / DC module is connected to the photovoltaic array, energy storage components, and frequency converter, respectively, to achieve energy transfer and conversion between different DC sources, including transmitting electrical energy from the photovoltaic array to the energy storage components for charging. The system transmits electrical energy from the energy storage components to the inverter side for use by the water pump. The inverter, connected to the photovoltaic array, energy storage components, DC / DC module, and power grid, is the core control device of the system. The inverter integrates a control unit with various real-time monitoring and control functions. It can monitor the output power of the photovoltaic array, the voltage status of the energy storage components, and the grid connection status and electrical parameters in real time. Simultaneously, the control unit can compare the photovoltaic power with the water pump's power demand, control the charging and discharging of the energy storage components, adjust the water pump speed, and control grid connection and disconnection. Through the coordinated operation of these components, the inverter automatically schedules energy flow based on photovoltaic power, energy storage voltage, and grid status, ensuring stable operation of the water pump under different operating conditions and maximizing the utilization of photovoltaic energy, protecting the energy storage during charging and discharging, and enabling flexible grid switching.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for multi-source coordinated scheduling and control of photovoltaic water pumps, characterized in that, include: The output power of the photovoltaic array and the power demand of the water pump are obtained from the real-time monitoring of the frequency converter, and the output power of the photovoltaic array is compared with the power demand. When the output power of the photovoltaic array is greater than the required power, the frequency converter determines whether to replenish the energy storage component based on the voltage status of the energy storage component. When the output power of the photovoltaic array is less than the required power, the frequency converter outputs the energy of the energy storage component to the water pump via the DC / DC module according to the voltage status of the energy storage component. When the energy storage component can no longer provide energy, the frequency converter controls the grid connection to ensure the water output of the water pump. Specifically, the voltage of the energy storage component is collected in real time to determine whether the voltage of the energy storage component is higher than a third preset threshold. When the voltage of the energy storage component is higher than the third preset threshold, it is determined that the energy storage component is in a dischargeable state, and the real-time power difference between the required power and the output power of the photovoltaic array is calculated. The real-time power difference is used as the power to be compensated. At the same time, a first-order low-pass filter is introduced to smooth the real-time power difference to obtain a smooth compensation power command, so as to filter out the high-frequency fluctuations of the output power of the photovoltaic array. According to the smooth compensation power command, the DC / DC module is controlled to output the energy of the energy storage component to the water pump at a preset power rate, so that the actual input power of the water pump is equal to or close to the required power, in order to compensate for the insufficient output power of the photovoltaic array and ensure the water output of the water pump. The voltage of the energy storage component is monitored in real time. When the voltage of the energy storage component is lower than the fourth preset threshold, it is determined that the energy storage component can no longer provide energy and a grid connection request is generated. In response to the grid connection request, the frequency converter synchronously detects the voltage, frequency and phase on the grid side, and controls the bidirectional AC / DC module to perform soft start, gradually increasing the grid output power from zero to the power required by the water pump at a preset power ramp rate; After the power grid is connected to supply power to the water pump, if the voltage of the energy storage component is detected to rise above the fifth preset threshold, or the output power of the photovoltaic array rises to a preset ratio that can independently meet the water pump's demand, the frequency converter actively controls the power grid to gradually disconnect at the same power ramp rate, achieving seamless disconnection from the power grid, reducing frequent grid switching, and further ensuring the water pump's output. When the output power of the photovoltaic array is less than the preset lower limit power, and the energy storage component cannot output energy to the water pump through the DC / DC module, and cannot be connected to the power grid, the frequency converter will reverse the energy of the photovoltaic array to the energy storage component through the DC / DC module.

2. The photovoltaic water pump multi-source coordinated scheduling and control method according to claim 1, characterized in that, The step of determining whether to replenish the energy storage component based on its voltage state includes: Determine whether the voltage of the energy storage component is lower than a first preset threshold. If so, determine that the energy storage component needs to be replenished, and prioritize replenishing the energy storage component with excess power from the photovoltaic array via a DC / DC module. If the voltage of the energy storage component is higher than a second preset threshold, the energy storage component is determined to be in an energy saturation state, and the pump speed is actively increased to convert excess electrical energy into mechanical energy.

3. The photovoltaic water pump multi-source coordinated scheduling and control method according to claim 1, characterized in that, The method further includes: The third preset threshold is corrected online based on the health status of the energy storage component and the ambient temperature.

4. The method for multi-source coordinated scheduling and control of photovoltaic water pumps according to claim 1, characterized in that, Also includes: During the compensation process, the change trend of the photovoltaic array output power is continuously monitored. If it is predicted that the output power of the photovoltaic array will rise rapidly within a preset time window and will soon exceed the required power, the energy output power of the energy storage component will be reduced in advance to achieve a seamless and smooth transition between photovoltaic output and energy storage discharge, and to prevent overcompensation and energy waste.

5. The photovoltaic water pump multi-source coordinated scheduling and control method according to claim 1, characterized in that, The step of storing the energy of the photovoltaic array in reverse via a DC / DC module to the energy storage component includes: Based on the real-time collected photovoltaic array output power, energy storage component voltage, and ambient temperature, the maximum allowable charging power and charging current threshold of the energy storage component are calculated. The inverter combines the output power of the photovoltaic array, the maximum charging power, and the charging current threshold to generate a charging power command, which controls the DC / DC module to establish a charging circuit and store the energy of the photovoltaic array in reverse to the energy storage component.

6. The photovoltaic water pump multi-source coordinated scheduling and control method according to claim 5, characterized in that, Also includes: During the reverse storage process, the voltage, charging current, and cell temperature of the energy storage component are continuously monitored. When the voltage, charging current, and cell temperature of the energy storage component exceed the preset safety range, the output power of the DC / DC module is dynamically reduced based on the maximum charging power threshold and the charging current threshold. When the voltage of the energy storage component reaches the second preset threshold, or when the energy of the photovoltaic array can meet the needs of the water pump, the charging circuit is gradually shut down.

7. A photovoltaic water pump multi-source coordinated scheduling and control system, characterized in that, This includes photovoltaic arrays, energy storage components, frequency converters, DC / DC modules, and power grids; The photovoltaic array is used to convert solar energy into direct current (DC) electricity. The energy storage component is used to store electrical energy and provide supplemental energy to the water pump; The DC / DC module is connected to the photovoltaic array, the energy storage component and the frequency converter respectively, and is used to realize energy transmission; The frequency converter is connected to the photovoltaic array, the energy storage component, the DC / DC module and the power grid respectively. The frequency converter has a built-in control unit for real-time monitoring of the output power of the photovoltaic array, the voltage status of the energy storage component and the status of the power grid, and for performing power comparison, energy storage charging and discharging control, water pump speed adjustment and power grid access control.

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