About the control of solar panels and solar pumping systems

- Jan 15, 2019-

Since the output of the solar panel photovoltaic array is the input of the motor water pump device, the volt-ampere characteristics of the two parts need to be well matched, and the building makes the photoelectric pump system run smoothly and efficiently. The photovoltaic array and the motor water pump are connected through the control part, and there are three basic connection methods. The simplest is the direct coupling mode. The main function of the control part is to turn on the circuit to start the pump and disconnect the circuit to stop pumping water. The second way is a system with a battery. The basic function of the control part is to control the charge and discharge of the electric ground. The third way is to automatically adjust the output of the input and input according to the intelligent electronic device, such as the maximum power controller, so that the PV array and the motor pump unit can be optimally matched. In addition, there is a two-stage square matrix connection control method that automatically connects the PV arrays in parallel or in series to improve the matching state.

 

(1) Direct coupling control

 

Photoelectric pump systems that use centrifugal pumps often use direct coupling because the performance of the centrifugal pump is well matched to the photovoltaic output characteristics. In designing such a system, the performance of the pump, the characteristics of the motor, and the parameters of the PV array must be carefully selected. Special development is also required when necessary. In this type of system control, the simplest controller is a knife switch that controls the start and stop of the pump manually. If the electronic system capable of automatically turning on and newly opening the circuit is used to control the start and stop of the water system, the working condition of the system can be improved, and the water volume can be increased by about 10% to achieve unattended operation. For example, a floating system with a buoyancy switch can automatically start and stop according to the depth of the water. An automatic controller with a light intensity probe can control the pumping and stopping according to the intensity of the solar radiation.

 

(2) Maximum power controller

 

The maximum power controller is commonly used in photovoltaic systems for volumetric pumps. This is an electronic adapter device with a single-chip microcomputer as the core device and the function of tracking the maximum output power point. It can adjust according to the irradiance, the current and voltage of the PV array, the head of the pump, the flow rate and other parameters, so that the square matrix The output operating point is close to the maximum power point; at the same time, the electrical parameters of the input motor pump unit can also make the unit work in an optimal state. Applying the maximum power controller also reduces the system's sunshine threshold.

 

Although the maximum power controller consumes about 5% of the output power of the PV array, the overall efficiency of the entire photoelectric pump system can be increased by more than 10%.