| This paper introduced photovoltaic pump system which adopts3-phase inductionmachine and established the mathematical model of each module of photovoltaic pumpsystem. In addition, the paper also studied the maximum power point tracking method,three-phase AC inverter voltage modulation strategy, photovoltaic pump system structure andcontrol strategy, hardware and software design.Based on steady-state mathematical model ofthe induction motor,it established a simplified photovoltaic pump system mathematical model.This model provided an effective theoretical support to improve the photovoltaic pumpsystem’s performance, which included reducing costs and improving efficiency.After studiedthe control strategy of photovoltaic pump, a segment synchronization DDS SVPWMalgorithm was proposed.In order to get the maximal efficiency of the induction machinewhich drived centrifugal pump, a equetion on power frequency and slip had been deduced. Inaddition, this paper also presented a engineering optimization fitting method of segmentationconstant ratio of voltage and frequency.Using CVT to achieve the maximum power pointtracking, and proposing commen design method of PI controller voltage in closed-loopcontrol. It also designed a1.5kW photovoltaic pump system which adopts3-phase inductionmachine with the corresponding control method. In order to improve the reliability of thesystem, it used Mitsubishi IPM (Intelligent Power Module) module as the main circuit of theinverter, and designed an economical and reliable drive and protection circuit. Using Sunpluscompany production SPMC75F2413A as control and protection microcontroller withefficient software algorithm. At last it tested photovoltaic pump systems to prove algorithmand system’s reliability, and given the experimental data and waveform. |
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