Multi-water-pump cooperative control system and method for photovoltaic energy supply

Abstract

The invention relates to a multi-water-pump cooperative control system and method for photovoltaic energy supply, and belongs to the technical field of multi-water-pump cooperative control for photovoltaic energy supply. Comprising a solar cell panel matrix, a photovoltaic MPPT controller, a storage battery pack, a water pump MPPT controller, a DC / AC inverter, a water pump set, a voltage and current acquisition module and a data processing controller, the solar cell panel matrix is composed of a plurality of solar cell single boards which are connected in series or in parallel, and the photovoltaic MPPT controller acquires output voltage and output current of the solar cell panel matrix in real time; the voltage value of the maximum power point is obtained based on an optimization control algorithm, so that the solar cell panel matrix maintains the maximum power point to charge the storage battery pack, the water pump group comprises a plurality of water pumps, and a water pump control strategy is preset in the data processing controller; under solar photovoltaic energy supply, intelligent maximum power point tracking adjustment of the multiple water pumps can be achieved under different conditions, and the working efficiency of the photovoltaic water pumps is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic-powered multi-water pump coordinated control, and in particular relates to a photovoltaic-powered multi-water pump coordinated control system and method. Background Art

[0002] With the widespread application of clean energy such as solar energy and wind energy, all walks of life use a large number of production equipment based on clean energy such as solar energy and wind energy as a form of energy supply in daily production and life. Solar energy is used in water pumping operations in industrial and agricultural production due to its low investment, easy installation and high economic benefits. However, traditional photovoltaic controllers can generally only achieve maximum power point tracking control of a single water pump equipment through MPPT technology. When multiple water pumps are used at the same time, it is impossible to make any water pump at the power output point with the best efficiency, which leads to the photovoltaic matrix under different meteorological conditions. The overall water lifting system efficiency is low when multiple water pumps are operating simultaneously, and the failure rate of each water pump is high. Problems such as this often occur.

[0003] Therefore, a photovoltaic-powered multi-pump collaborative control system and method is needed, which can realize intelligent maximum power point tracking and adjustment of multiple water pumps under different meteorological conditions under solar photovoltaic power supply, thereby improving the working efficiency of photovoltaic water pumps. Summary of the invention

[0004] In order to overcome the problems mentioned in the background technology, the present invention provides a photovoltaic-powered multi-pump coordinated control system and method. Under solar photovoltaic power supply, the present invention can realize intelligent maximum power point tracking and adjustment of multiple water pumps under different meteorological conditions, thereby improving the working efficiency of photovoltaic water pumps.

[0005] To achieve the above-mentioned purpose, the present invention is implemented through the following technical solutions: a photovoltaic-powered multi-pump coordinated control system and method includes a solar panel matrix 1, a photovoltaic MPPT controller 2, a battery pack 3, a water pump MPPT controller 4, a DC / AC inverter 5, a water pump group 6, a voltage and current acquisition module 7 and a data processing controller 8, wherein the solar panel matrix 1 is composed of a plurality of solar panels connected in series or in parallel, the photovoltaic MPPT controller 2 collects the output voltage and output current of the solar panel matrix 1 in real time, and obtains the voltage value of the maximum power point based on the optimization control algorithm, so that the solar panel matrix 1 maintains the maximum power point to charge the battery pack 3, the water pump group 6 includes a plurality of water pumps, each of the water pumps is respectively connected to one of the DC / AC inverters 5, each of the DC / AC inverters 5 is respectively connected to one of the water pump MPPT controllers 4, the water pump MPPT controller 4 is connected to the battery pack 3, the voltage and current acquisition module 7 collects the voltage and current information of each device to the data processing controller 8, and the data processing controller 8 is preset with a water pump control strategy.

[0006] Furthermore, the optimization control algorithm is specifically as follows: Select three voltage points of -10%Un, Un, and +10%Un of the rated voltage of the solar panel matrix as difference points u0, u1, and u2 respectively. The corresponding function values ​​p0, p1, and p2 represent the power values ​​of the three sampling points respectively. The quadratic difference function is constructed as follows: Where Y(u) is a quadratic interpolation polynomial, y0(u), y1(u), y2(u) are quadratic interpolation basis functions, and the difference points u0, u1, u2 are respectively substituted into the quadratic interpolation basis functions to obtain Therefore, the quadratic interpolation function is: Derivative of the quadratic interpolation function yields: Where: set up , the voltage value u of the maximum power point can be obtained as: .

[0007] Furthermore, the DC / AC inverter 5 is an inverter based on PWM technology, and the water pump MPPT controller controls the input or output of the DC / AC inverter to adjust the power and speed of the water pump.

[0008] Furthermore, the voltage and current acquisition module 7 is used to collect voltage and current information of the solar panel matrix 1, the battery group 3, the DC / AC inverter 5 and each water pump in the water pump group 6, and send the voltage and current information to the data processing controller 8.

[0009] Further, the data processing controller 8 is provided with a control strategy for the water pump group based on the actual operation data of the water pump and the voltage and current of the solar panel matrix 1 and the voltage and current of the battery group 3 collected by the voltage and current collection module 7. The control strategy of the water pump group includes a main control strategy and a control strategy of the water pump MPPT controller; Among them, the control steps of the master control strategy are specifically as follows: S101: The voltage and current acquisition unit 7 detects that the voltage of the solar panel matrix 1 is U1 and the current is I1 at time t0; the voltage of the battery group 3 is U2 and the current is I2, and the rated voltage of the battery group 3 is set to U0; S102: When U1≥U2>U0, I1≥I2, the data processing controller starts the water pumps one by one through the water pump MPPT controller. Each water pump is equipped with a separate water pump MPPT controller, so that each water pump is at the maximum power point for pumping operation after starting; S103: When 0.2U2≤U1<0.8U2, 0.3I2≤I1<0.7I2, the first 30% of the water pumps with larger power output in the water pump group are shut down through the data processing controller, and the other water pumps operate normally; S104: When 0<U1<0.2U2, 0<I1<0.3I2, the data processing controller stops the water pumps with the top 50% power output among the remaining water pumps in the water pump group, and the other water pumps operate normally; S105: When U1=0, I1=0, U2≤0.5U0, the water pump group is shut down through the data processing controller.

[0010] The specific steps of the control strategy of the water pump MPPT controller during water pump operation are: S201: For each water pump in the water pump group, the required head and flow rate are configured according to the actual usage scenario, and the minimum power Pi and the minimum speed ni of the variable frequency water pump that need to be met by the variable frequency water pump are calculated through the data processing controller, and the volume Vi of the water tank that the water pump lifts to the high place is determined; S202: When Pi≤U2*I2, the water pump MPPT controller controls the voltage of the input DC / AC inverter to be U2, and controls the output voltage and frequency of the DC / AC inverter to make the water pump speed greater than ni, and adjusts the water pump speed in real time according to the change of the water tank volume Vi; S203: When Pi>U2*I2, the water pump MPPT controller increases the input voltage of the DC / AC inverter, and controls the output voltage and frequency of the DC / AC inverter to keep the water pump speed greater than ni, and adjusts the water pump speed in real time according to the change of the water tank volume Vi; S204: When the water pump receives a stop signal, the water pump stops running.

[0011] Beneficial effects of the present invention: The present invention achieves a significant improvement in the power utilization rate of solar panels through the algorithm of the voltage value of the maximum power point of the photovoltaic MPPT controller after optimization; the control strategy of the water pump MPPT controller proposed in the present invention can achieve the optimization of the power of a single water pump under solar energy supply, and can flexibly adjust the speed of the variable-speed water pump according to actual operation needs, which can effectively improve the operation efficiency of a single water pump in the system and reduce the failure rate of the water pump; the present invention can achieve that when multiple water pumps are used at the same time, especially when the heads of the multiple water pumps are different, any water pump is at the power output point of optimal efficiency, thereby greatly improving the energy utilization rate of multiple water pumps powered by solar energy, and making the operation mode of multiple water pumps under the solar energy function more flexible, more efficient, and more economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the system of the present invention.

[0013] Figure 2 It is a schematic diagram of the master control strategy flow of the present invention.

[0014] Figure 3 It is a control strategy flow chart of the water pump MPPT controller of the present invention.

[0015] Reference numerals: solar panel matrix 1, photovoltaic MPPT controller 2, battery pack 3, water pump MPPT controller 4, DC / AC inverter 5, water pump group 6, voltage and current acquisition module 7, data processing controller 8. DETAILED DESCRIPTION

[0016] In order to make the objectives, technical solutions and beneficial effects of the present invention more clear, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings to facilitate understanding by technicians.

[0017] like Figure 1-3The present invention discloses a photovoltaic-powered multi-pump coordinated control system and method, the photovoltaic-powered multi-pump coordinated control system and method comprising a solar panel matrix 1, a photovoltaic MPPT controller 2, a battery pack 3, a water pump MPPT controller 4, a DC / AC inverter 5, a water pump group 6, a voltage and current acquisition module 7 and a data processing controller 8, the solar panel matrix 1 is composed of a plurality of solar panels connected in series or in parallel, the photovoltaic MPPT controller 2 collects the output voltage and output current of the solar panel matrix 1 in real time, and obtains the voltage value of the maximum power point based on an optimization control algorithm, so that the solar panel matrix 1 maintains the maximum power point to charge the battery pack 3, the photovoltaic MPPT controller generates a reference voltage signal by a single-chip microcomputer, and compares it with the currently collected voltage signal, obtains the DC-DC duty cycle by a PI controller, and finally compares it with a triangle wave, generates PWM to control the DC-DC, and realizes maximum power point tracking. The water pump group 6 includes multiple water pumps, each of which is connected to one of the DC / AC inverters 5, each of which is connected to one of the water pump MPPT controllers 4, the water pump MPPT controller 4 is connected to the battery pack 3, the voltage and current acquisition module 7 collects voltage and current information of each device to the data processing controller 8, the data processing controller 8 is preset with a water pump control strategy, and the data processing controller 8 controls each water pump through the water pump MPPT controller 4.

[0018] The solar panel matrix converts solar energy into electrical energy, and stores the electrical energy in the battery pack based on the optimization control algorithm through the photovoltaic MPPT controller to improve the utilization rate and supply power to the water pump group. The battery pack has the characteristics of stable voltage, low self-discharge rate, long service life, strong deep discharge capacity, high charging efficiency, low maintenance or maintenance-free, and wide operating temperature range. The water pump group includes multiple water pumps, which can be composed of multiple variable frequency water pumps with the same power or multiple variable frequency water pumps with different powers. The variable frequency water pump is mainly used to pump water from the water source to a high place or a distant place. The variable frequency water pump should adopt a centrifugal pump with a cast iron shell and has the characteristics of rust and corrosion resistance. And the power parameters and head of the variable frequency water pump can be configured according to actual needs. The data processing controller can calculate the minimum power Pi and the minimum speed ni of the variable frequency water pump according to the head and flow rate required for the actual use scenario of each variable frequency water pump.

[0019] The optimization control algorithm is specifically: Select three voltage points of -10%Un, Un, and +10%Un of the rated voltage of the solar panel matrix as difference points u0, u1, and u2 respectively. The corresponding function values ​​p0, p1, and p2 represent the power values ​​of the three sampling points respectively. The quadratic difference function is constructed as follows: Where Y(u) is a quadratic interpolation polynomial, y0(u), y1(u), y2(u) are quadratic interpolation basis functions, and the difference points u0, u1, u2 are respectively substituted into the quadratic interpolation basis functions to obtain Therefore, the quadratic interpolation function is: Derivative of the quadratic interpolation function yields: Where: set up , the voltage value u of the maximum power point can be obtained as: By using the optimization control algorithm, the voltage value of the maximum power point of the solar panel matrix can be obtained, so that the battery pack can be continuously charged at the maximum power point of the solar panel matrix. The algorithm of the voltage value of the maximum power point of the optimized photovoltaic MPPT controller has achieved a significant increase in the power utilization rate of the solar panel, which is at least 20% higher than the MPPT strategy of the existing technology.

[0020] The DC / AC inverter 5 is an inverter based on PWM technology. The water pump MPPT controller realizes fine control of the water pump by controlling the input or output of the DC / AC inverter; the DC / AC inverter is mainly used to convert the DC power output by the battery pack into frequency-adjustable sinusoidal AC power through PWM chopping conversion, and serve as the input power supply of the water pump group. The power requirement of the DC / AC inverter is not less than 1.3 times the rated power of the water pump, the inverter efficiency is not less than 85%, the output AC voltage ripple factor is not less than 1%, and it has overcurrent protection, low voltage protection, overvoltage protection, short circuit protection, high temperature protection and other protection functions. The water pump MPPT controller is mainly used to control the input voltage, output voltage and output frequency of the DC / AC inverter. The power of the variable frequency water pump is controlled by controlling the input voltage and output voltage of the DC / AC inverter, and the speed of the variable frequency water pump is controllably adjusted by controlling the output frequency of the DC / AC inverter.

[0021] The voltage and current acquisition module 7 is used to collect voltage and current information of the solar panel matrix 1, the battery group 3, the DC / AC inverter 5 and each water pump in the water pump group 6, and convert the voltage and current information into digital signals through digital-to-analog conversion and send them to the data processing controller 8, so that the data processing controller can implement the control strategy.

[0022] The data processing controller 8 is provided with a control strategy for the water pump group based on the actual operation data of the water pump and the voltage and current of the solar panel matrix 1 and the voltage and current of the battery group 3 collected by the voltage and current collection module 7. The control strategy of the water pump group includes a main control strategy and a control strategy of the water pump MPPT controller during the operation of the water pump; Among them, the control steps of the master control strategy are specifically as follows: S101: The voltage and current acquisition unit 7 detects that the voltage of the solar panel matrix 1 is U1 and the current is I1 at time t0; the voltage of the battery group 3 is U2 and the current is I2, and the rated voltage of the battery group 3 is set to U0; S102: When U1≥U2>U0, I1≥I2, the data processing controller starts the water pumps one by one through the water pump MPPT controller. Each water pump is equipped with a separate water pump MPPT controller, so that each water pump is at the maximum power point for pumping operation after starting; S103: When 0.2U2≤U1<0.8U2, 0.3I2≤I1<0.7I2, the first 30% of the water pumps with larger power output in the water pump group are shut down through the data processing controller, and the other water pumps operate normally; S104: When 0<U1<0.2U2, 0<I1<0.3I2, the data processing controller stops the water pumps with the top 50% power output among the remaining water pumps in the water pump group, and the other water pumps operate normally; S105: When U1=0, I1=0, U2≤0.5U0, the water pump group is shut down through the data processing controller.

[0023] The specific steps of the control strategy of the water pump MPPT controller during water pump operation are: S201: For each water pump in the water pump group, the required head and flow rate are configured according to the actual usage scenario, and the minimum power Pi and the minimum speed ni of the variable frequency water pump that need to be met by the variable frequency water pump are calculated through the data processing controller, and the volume Vi of the water tank that the water pump lifts to the high place is determined; S202: When Pi≤U2*I2, the water pump MPPT controller controls the voltage of the input DC / AC inverter to be U2, and controls the output voltage and frequency of the DC / AC inverter to make the water pump speed greater than ni, and adjusts the water pump speed in real time according to the change of the water tank volume Vi; S203: When Pi>U2*I2, the water pump MPPT controller increases the input voltage of the DC / AC inverter, and controls the output voltage and frequency of the DC / AC inverter to keep the water pump speed greater than ni, and adjusts the water pump speed in real time according to the change of the water tank volume Vi; S204: When the water pump receives a stop signal, the water pump stops running.

[0024] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A photovoltaic powered multi-pump coordinated control system and method, characterized in that: The photovoltaic-powered multi-pump coordinated control system and method comprises a solar panel matrix (1), a photovoltaic MPPT controller (2), a battery pack (3), a water pump MPPT controller (4), a DC / AC inverter (5), a water pump group (6), a voltage and current acquisition module (7) and a data processing controller (8). The solar panel matrix (1) is composed of a plurality of solar panels connected in series or in parallel. The photovoltaic MPPT controller (2) acquires the output voltage and output current of the solar panel matrix (1) in real time, and obtains the maximum power based on an optimization control algorithm. The voltage value at the power point is set so that the solar panel matrix (1) maintains the maximum power point to charge the battery pack (3). The water pump group (6) includes a plurality of water pumps, each of which is connected to one of the DC / AC inverters (5). Each of the DC / AC inverters (5) is connected to one of the water pump MPPT controllers (4). The water pump MPPT controller (4) is connected to the battery pack (3). The voltage and current acquisition module (7) acquires voltage and current information of each device and transmits it to a data processing controller (8). The data processing controller (8) is preset with a control strategy for the water pump group.

2. A photovoltaic powered multi-pump coordinated control system and method according to claim 1, characterized in that: The optimization control algorithm is specifically: Select three voltage points of -10%Un, Un, and +10%Un of the rated voltage of the solar panel matrix as difference points u0, u1, and u2 respectively. The corresponding function values ​​p0, p1, and p2 represent the power values ​​of the three sampling points respectively. The quadratic difference function is constructed as follows: Where Y(u) is a quadratic interpolation polynomial, y0(u), y1(u), y2(u) are quadratic interpolation basis functions, and the difference points u0, u1, u2 are respectively substituted into the quadratic interpolation basis functions to obtain Therefore, the quadratic interpolation function is: Derivative of the quadratic interpolation function yields: Where: set up , the voltage value u of the maximum power point can be obtained as: 。 3. A photovoltaic powered multi-pump coordinated control system and method according to claim 1, characterized in that: The DC / AC inverter (5) is an inverter based on PWM technology, and the water pump MPPT controller controls the input or output of the DC / AC inverter to adjust the power and speed of the water pump.

4. A photovoltaic powered multi-pump coordinated control system and method according to claim 1, characterized in that: The voltage and current acquisition module (7) is used to collect voltage and current information of the solar panel matrix (1), the battery group (3), the DC / AC inverter (5) and each water pump in the water pump group (6), and send the voltage and current information to the data processing controller (8).

5. A photovoltaic powered multi-pump coordinated control system and method according to claim 3, characterized in that: The data processing controller (8) is provided with a control strategy for the water pump group based on the actual operation data of the water pump and the voltage and current of the solar panel matrix (1) and the voltage and current of the battery group (3) collected by the voltage and current collection module (7), wherein the control strategy for the water pump group includes a main control strategy and a control strategy of the water pump MPPT controller during the operation of the water pump; Among them, the control steps of the master control strategy are specifically as follows: S101: The voltage and current acquisition unit 7 detects the voltage U1 and current I1 of the solar panel matrix 1 and the voltage U2 and current I2 of the battery group 3 at time t0, and sets the rated voltage of the battery group 3 to U0; S102: When U1≥U2>U0, I1≥I2, the data processing controller starts the water pumps one by one through the water pump MPPT controller. Each water pump is equipped with a separate water pump MPPT controller, so that each water pump is at the maximum power point for pumping operation after starting; S103: When 0.2U2≤U1<0.8U2, 0.3I2≤I1<0.7I2, the first 30% of the water pumps with larger power output in the water pump group are shut down through the data processing controller, and the other water pumps operate normally; S104: When 0<U1<0.2U2, 0<I1<0.3I2, the data processing controller stops the top 50% of the pumps in the remaining pump group in terms of power output, and the other pumps operate normally; S105: When U1=0, I1=0, U2≤0.5U0, the water pump group is stopped through the data processing controller; The specific steps of the control strategy of the water pump MPPT controller during water pump operation are: S201: For each water pump in the water pump group, the required head and flow rate are configured according to the actual usage scenario, and the minimum power Pi and the minimum speed ni of the variable frequency water pump that need to be met by the variable frequency water pump are calculated through the data processing controller, and the volume Vi of the water tank at the high place that the water pump lifts water to is determined; S202: When Pi≤U2*I2, the water pump MPPT controller controls the voltage of the input DC / AC inverter to be U2, and controls the output voltage and frequency of the DC / AC inverter to make the water pump speed greater than ni, and adjusts the water pump speed in real time according to the change of the water reservoir volume Vi; S203: When Pi>U2*I2, the water pump MPPT controller increases the input voltage of the DC / AC inverter, and controls the output voltage and frequency of the DC / AC inverter to keep the water pump speed greater than ni, and adjusts the water pump speed in real time according to the change of the water reservoir volume Vi; S204: When the water pump receives a stop signal, the water pump stops running.

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