| Given pervasive renewable energy, the solar energy exploitation, especially photovoltaic generation is developed rapidly and gradually becomes an important research field. This paper presented analysis and study on topology and control of DC-AC link of PV inverter, which can operate independently and grid-connected. Finally, the experimental prototype was implemented.Firstly, topology of DC-AC link of inverter was discussed, as well the structure and parameters of output filter for operation independently and grid-connected were proposed in detail, which were testified by simulation.Subsequently, control strategy for operation independent and grid-connected was presented. Waveform feedback was introduced into the controller, which could not only suppress harmonic and improve power factor, but also enhance dynamic performance to meet real-time demand. The feedbacks signal regulation, sinusoidal wave generator, and phase-lock loop were realized by digital control, while self-tuning of PID parameter was implemented to attenuate influence in the presence of load variation.Considering the actual operation condition of PV inverter, the fault of over current, the DC biasing, and island effect were analyzed, and the protective measures against corresponding faults were designed, which improved function of PV inverter.Finally, the above algorithm and the protective measures in digital control were realized by virtue of the TMS320LF2407A of TI Incorporated. Software and hardware design for DC-AC link of PV inverter were included; besides, the issues which were confronted and overcome during designing in practice were also prescribed. The prototype of PV inverter has been implemented by combination of DC-DC link and DC-AC link. The experimental waveforms were illustrated as well, which achieved the specification. |
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