A SINGLE-CHIP-MICROPROCESSOR CONTROLLED PHOTOVOLTAIC AC SUBMERSIBLE SCREW WATER PUMP SYSTEM

An 1 KWp photovoltaic AC water pump system controlled by a single chip microproces­sor is presented. A submersible screw electric pump is drived by a PWM MOSFET inverter. The PWM control pulse for the inverter is generated by an IC HEF4752. Since the screw pump has constant torque property, a simpler maximum power tracking method without the need of a DC-DC converter, which is called Maximum Frequency Point Tracking(MFPT), is presented, which simplifies the control complexity.