Research Of The Control Techniques On The Practicable And High Efficiency Photovoltaic Water Pump System

Photovoltaic pump system, which is an important kind of solar energy applications, have tremendous social and economical advantages.In this dissertation, deep research of the control techniques has been done based on the characteristics of photovoltaic pump driven by permanent magnet brushless DC motor, including detect of rotor position, starting methods, the control of commutation. In addition, a practicable and high efficiency controller of photovoltaic pump is designed. The main contents in this paper are:1. Different rotor position detecting methods of sensorless permanent magnet brushless DC motor are analysed, and accurate detect of motor rotor position by the virtual neutral point back-EMF detect method is realized.2. Different starting methods of permanent magnet brushless DC motor are compared, a starting method of self-search best commutation point of permanent magnet brushless DC motor is put forward.3. A controller for photovoltaic pump, adopts chip MR16 for control chip, which is a kind of micro-controllers of 68HC08 series, is designed. The system also accomplishes several important objects, such as MPPT of photovoltaic arrays, unmanned supervision of the system, fault detection, etc.4. The results of the experiment show that the prototype, which is made on the base of the principle above, can control the motor to complete the accurate commutation. The system operates stably and presents good static and dynamic performances.