Is it better to use a DC water pump or an AC water pump in a solar pump system？

Many people will simply believe that solar energy produces DC, so DC motor is more suitable. This view is inaccurate.

Generally speaking, high-power (not less than 4kw) pumps are more suitable for AC motors, and low-power pumps are more suitable for BLDC motors.

In fact, DC can only directly drive brushed motor, and BLDC motor still needs a controller to operate.

However, the service life of the brush motor is very short, the life of the brush may not exceed three months. Frequent replacement of brushes or motors is not a wise choice. In most cases, BLDC motor needs to be selected, which means that like AC motor, converter is indispensable.

Because the torque of BLDC motor is small, it is difficult to use in high-power water pump.

On the other hand, although it also has low power AC motors, it is difficult to match solar panels. If the power requirements of the motor are met, the voltage of the solar panel is still not enough. If the voltage of the solar panel meets the requirements, the power will exceed a lot. Although the pump can work normally, it is a great waste for the solar panel.
https://www.solar660.com/d/8-how-to-configure-a-solar-ac-pump-system

In summary, we recommend BLDC motor for low-power solar pump system, and AC asynchronous motor for high-power systems.

6 months later

  • ZZZZ

    • Post #4

    Is it better to use synchronous motor or asynchronous motor for AC water pump?

      9 days later

      ZZZ
      In the solar pump system, asynchronous motor is better.

      The main reason is, the asynchronous motors are more adaptable. Synchronous motors are prone to reversible or irreversible demagnetization of permanent magnets, when encountering high temperature, voltage mutation, loss of step (such as motor jamming, stalling), etc., thereby reducing torque or damaging the motor.
      However, it is difficult for PV array to provide a stable voltage, so synchronous motors are not suitable for photovoltaic water pump systems.

      The following is a comparison of the advantages and disadvantages of synchronous motors and asynchronous motors.