Power Inverter And Its Parallel Distributed Independent Photovoltaic Power Generation System

Shortage of energy sources and pollution of environment in the world are becoming more and more serious. Worldwide attention has been paid on this issue. Given pervasive renewable energy, the solar energy exploitation, especially photovoltaic (PV) generation is developed rapidly and gradually becomes an important research field. Recently, with the development of PV technology ,the role of PV generation systems is gradually changed from supplemental energy to substitute energy. And stand-alone and grid-connected PV generation systems will be the trend among PV applications. This paper deals with such key problems as the topology of high-frequency line inverter, digital control technologies for the output voltage waveform of the inverter power supply, the multi-module redundant inverter system and so on by establishing related simulation models, applying novel control strategies and experiments validation.First, on the basis of circuit model of voltage mode high-frequency line inverter power supply, the continuous and discrete space-state mathematic models are established, which provide theoretical basis for the design of control system. the inverter simulation model is established by the simulation software of PSIM, which is used to validate the feasibility of every control strategy.Next, the repetitive control technology is studied for the PV inverter based on voltage feedback control scheme. According to the research on trace error and stability, mechanism that the repetitive control eliminates the periodical distortion of the output voltage is clean. The defect of repetitive control is its one based-period delay on control, which affects the dynamic response characteristic of the system, multiple control strategy based on repetitive control is applied to improve inverter transient response characteristic. The experiment result shows that the harmonic distortion of output voltage wave is reduced by the multiple control strategy , which can provide advantages to the parallel inverter system. Then, a distributed control scheme with instantaneous current sharing is developed for redundant parallel inverter power supply system. Current sharing based upon the average current method is realized by using a shared bus to connect all the parallel modules without extra control modules. The shared bus consists of only there noise insensitive lines regardless of how many modules are in parallel. The voltage regulator also serves as the current deviation controller. As a result, the system has fast dynamic response and equal current load sharing under every condition.Finally, the experiment results are achieved and the important waveforms are discussed. Some questions are provided and some advice for future work are given out.