Research On Closed-Loop Power Decoupling Control And Active Power/Reactive Power Control Of Single-Phase VSI-BPD

In small distributed power generation systems,single-phase inverters are commonly used to exchange energy between DC power sources and AC,such as solar power generation,energy storage units and fuel cells.However,the double-line-frequency pulsating power problem inherent in single-phase inverter systems,not only depends on the electrolytic capacitors with low reliability,but also affects the working efficiency and life of DC distributed power supply and energy storage unit.Therefore,power decoupling technology is required,to solving the problem.And with the large number of renewable energy sources connected to the grid,power system requires flexible active and reactive power control for stable operation of utility,which has become one of technical codes for the systems.Based on a new single-phase power decoupling inverter topology(Single-phase voltage source bridge inverter topology with boost and power decoupling capability,Single-phase VSI-BPD)proposed by the research group,this paper focuses on power decoupling control and reactive/reactive power control,and the main research content and innovation lies in:1.Taking a Single-phase VSI-BPD topology as the research object,the power decoupling control strategy is introduced,the parameters of the inductor and power decoupling capacitor in the power decoupling circuit,the filter capacitor and the filter inductor in the filter are designed,laying the foundation for closed-loop power decoupling control strategy and inverter control strategy in later chapters.Based on the RTLAB hardware-in-the-loop semi-physical simulation platform,the simulation model of open-loop load of the topology is built,and the topology boost and power decoupling functions are verified by hardware-in-the-loop simulation.2.To analyzing the influence of power decoupling effect,while the series resistance of the inductor and the parameter drift of the power decoupling capacitance in the power decoupling circuit,and the problems of power decoupling control of single-phase VSI-BPD topology,a closed-loop power decoupling control strategy is proposed in this paper.Finally,build a simulation model to verify.The simulation results show that in the case of without closed-loop power decoupling control strategy,the DC current contains double-line-frequency component and the ripple ratio is 30%,in the case of with the closed-loop power decoupling control strategy,the DC current contains double-line-frequency component,and the ripple ratio is reduced to 5%,which significantly improves the power decoupling effect.3.The single-phase VSI-BPD topology inverter control is based on the stationary coordinate system,which is inconvenient for the independent control of the active and reactive power,and PR is not easy to implement in actual scenarios.To solving the problems of inverter control of the single-phase VSI-BPD topology,the inverter control strategy,based on the PI controller with single-phase d-q transformation,is applied to the single-phase VSI-BPD topology in this paper,which can not only realize the independent control of active power and reactive power,but also replace the proportional resonance controller with the traditional PI controller which is easy to implement..The mathematical modeling of single-phase inverter in stationary coordinate system and rotating coordinate system are carried out respectively.4.At the same time,the relationship between the power decoupling control strategy and the inverter reactive power control,and the relationship between the power decoupling capacitance and the power factor are analyzed.The value range of power decoupling capacitors that meet the requirements of power decoupling control and reactive power control is obtained,which provides a theoretical basis for the optimal design of system parameters.5.The simulation model is built in the simulation environment of PSIM11.0,and the proposed control method is simulated and verified.The simulation results show that the single-phase VSI-BPD topology can complete the active/reactive power output to the grid at the same time under the premise of power decoupling.