The Research Of Sensorless BLDC Motor Control Used In Photovoltaic Pumps

This paper analyses the realization of "neutral simulator", then use circuit to measure the "across the zero point". This paper also thinks over how to use the circuit in high voltage sensorless Bldc motor, use the circuit to realize the precision changing of coil.The Photovoltaic pumps system select the sensorless Bldc motor to drive the pump. We also select the microchip PIC16F877 made by Microchip Co.Ltd as a control chip to realize micro-computer control. This system use three separate channel to find out the "across the zero point" of each back-EMF. The program use digital filter to wipe off the PWM interferences and the commutating interferences. In this paper we discuss how to realize the CVT or MPPT in Photovoltaic pumps system, and program the software.The results of the experiment show that this system ,which is made on the base of the theory above, can control the sensorless Bldc motor to complete the exact commutation. The system presents good static and dynamic performance. The drawback of the system is show in the end. We also give some advice for improvement.