China's per capita water shortage, frequent droughts, serious soil erosion, and the power grid can not fully cover the remote mountainous areas, seriously affecting people's lives, drinking water, agricultural production and other issues in these places. In recent years, China's photovoltaic industry has been rapidly Development, cost has been declining year by year, photovoltaic products have begun to enter people's lives, among them, photovoltaic water pumping system is the combination of photovoltaic products and water, innovative application to domestic water, agricultural irrigation, ecological restoration, grassland animal husbandry and other needs, photovoltaic water pumping system as The new application in the field of photovoltaics can not only avoid a large amount of capital investment in the construction of power grid infrastructure, but also solve the problem of lack of electricity and water shortage in agricultural production.
The typical photovoltaic water pumping system is mainly composed of four components: photovoltaic module, photovoltaic bracket, water pump inverter and water pump. The clean energy solar energy is used as the power to directly drive the pump to pump water, and the water storage instead of electricity storage, without energy storage device. Greatly reduce the construction cost and maintenance cost of the system. The system is widely used by people because of its environmental protection, energy saving, easy installation and maintenance, and good economy.
The design of the PV pumping system first needs to do a good job of the customer demand survey in the early stage, such as: system use, customer daily water consumption, lift and local lighting information. Only by fully understanding the specific needs of customers can we provide the best solution for customers. , to meet the needs of customers to the maximum extent. The design of photovoltaic pumping system mainly includes pump selection, pumping inverter selection and PV module design.
1. Pump selection
1.1 Traffic determination
The flow rate of the pump is also called the water delivery volume. The flow rate of the system is determined mainly according to the customer's water consumption and local lighting conditions. For details, please refer to the following formula:
1.2 lift determination
The lift refers to the height at which the pump can lift water. It is an important performance parameter of the pump. It can be measured according to the actual conditions of the customer's project. The following is the calculation method for the lift:
Pump head = static head + horizontal conveying distance + loss head
The static lift refers to the height difference between the suction point of the pump and the high control point, such as pumping water from a deep well and sending it to a high water tank. The static lift is the height difference between the suction inlet of the clear water tank and the water tank at the high point; As shown in the figure, the static head is H1+ H3;
The horizontal conveying distance is shown in Figure H2. When the head is generally calculated, the head is calculated as a head of 1m every 10m in the horizontal direction;
The loss head is usually 6~9% of the net head, such as water pipe elbow, water head, etc., generally 1~ 2m.
After the flow and head of the pump are determined, the pump model can be basically determined. If the customer is pumping in a deep well, it is also necessary to consider that the size of the pump is smaller than the diameter of the deep well.
2. Pump inverter selection
The photovoltaic pumping inverter is the most important equipment in the photovoltaic pumping system. As the control and regulator of the whole system, it always performs maximum power point tracking and adjusts the output frequency in real time according to the change of sunshine, thus controlling and regulating the pump work. The power of the transformer is mainly determined by the pump motor. For the reliable operation of the system, it is generally recommended to select not less than the power of the pump motor, and consider the input voltage and wiring mode of the pump (single-phase or three-phase), and finally determine the pumping inverter. Model number.
3. Photovoltaic module design
In remote mountainous areas, there is no power grid or diesel generator as a supplementary power source. The power of the photovoltaic water pumping system is all provided by the electricity generated by the photovoltaic modules. In order to ensure the water demand of the customers, considering the tilt angle of the photovoltaic panels, temperature, shadow blocking, The influence of factors such as dust on the system, and the over-distribution capability of the pumping inverter. It is generally recommended that the power of the PV module is between 1.1 and 1.5 times the rated power of the inverter, generally 1.2 times.
4. Typical design scheme of 5.5kW water pumping system
Background of the project:
There is no mains and generators at the project site, and a PV water pumping system is designed for a customer. The deep well pumping water is used for farmland irrigation. The specific information is as follows;
a) The depth of the well is about 60 meters, the lift is about 50 meters, and the diameter is about 250mm;
b) A total of 80 mu of dry land needs to be irrigated, with about 70 water per day;
c) The average local sunshine of the irrigation device is about 4 hours/day
4.1 Pump selection
According to the above information, the pump flow requirement is 70m3/(4h* 0.85) = 20.6m3/h, the lift is 50m, the pump can be selected from Ruirong's R150-DS- 05, the motor power is 4kW, and the applicable diameter is 150mm. Meet the requirements. The following are the specific parameters of the pump:
4.2 Yangshui inverter selection
According to the pump motor power is 4kW, the input voltage is three-phase 380Vac, the pump inverter selects the SPRING5500 of Jingfuyuan, and the output rated power is 5.5kW.
4.3 PV module design
The selected pumping inverter SPRING5500 has a rated output of 5500W. Considering the local lighting conditions, the optional 1.1 times component is 1.1×5500= 6050W.
Founded in 2003, Shenzhen Jingfuyuan Technology Co., Ltd. is a national high-tech enterprise integrating R&D, production, sales and service. The company has long been focusing on the power electronics industry and has a 0.55-75kW photovoltaic pumping inverter. Single, three-phase AC output, support a variety of pump motors, IP65 protection level (over 22kW power increase outdoor cabinet, protection class IP54), suitable for outdoor use, and optional diesel or commercial power as backup power, support 24 hours a day Power generation Yangshui. Jingfuyuan always adheres to the concept of 'Tiandao rewards diligence, keep improving', and strives to create more value for customers.
