Research On Bus Voltage Ripple Compensation And Control Strategies Of Dual-mode Inverter

With the advent of traditional fossil energy crisis, the community is constantly looking for its alternatives, and then completes the adjustment of energy structure. In the wind, solar, tidal energy, biofuels and other renewable energy sources, solar energy is popular in people of all ages because it’s abundant, clean and low-carbon. Its growth is very impressive in recent years, and the authorities predicted that it will maintain a good development trend in the next few years. This article conforming to the concept that the vacant roof provides for the aged launched a related study in terms of the dual-mode inverter.First, concerning the control strategy for steady-state operation of the dual-mode inverter, when the system switches to network operation mode from off-line operation mode, the controlled object has become LCL filter from the LC filter, so the article was designed to the voltage and current double loop PI controller corresponding to run off-line and the dual current loop PI controller corresponding to run network operation. It can be seen from the internal model principle, PI controller can not given unbiased tracking to sinusoidal signal, thus this paper presents an improved scheme that is embedded with repetitive control and resonance control on the basis of the double loop controller. Then the simulation results also verify the effectiveness of the improvement program.Secondly, because the dual-mode inverter needs to protect uninterrupted power supply for the important load, the system not only has to ensure steady operation, but also need to consider the seamless switching between the two modes. This paper analyzes causes of voltage mutation process in mode switching, and gives the control strategy to reduce voltage mutation through introduction of transition mutation, then comparing the simulation waveform then also verifies the effectiveness of the control strategy.Thirdly, for the inverter, the DC bus voltage ripple compensation can improve the inverter voltage THD and prolong the life of DC link capacitors. After this paper analyzes causes of the DC bus voltage ripple, a new ideas has been proposed that using battery charge and discharge achieves bus voltage ripple compensation, then the articles gives modeling analysis and controller design on the battery charge and discharge, and the simulation analysis verifies the conclusion that the system can complete the ripple compensation by the battery charge and discharge being in accordance with 100 hz low-frequency AC current.Fourth, in order to verify the practicality of control strategy for the dual-mode inverter running on steady-state, seamless switching and ripple compensation, this article builds a prototype from both hardware and software, the analysis and design of this paper are testified by collecting experimental waveforms.