Research On New Single-phase Inverter With Power Decoupling And Reactive Power Control

The double-frequency current ripple exists on the DC side of the single-phase converter,which negatively affects photovoltaics,batteries,fuel cells,and LED power supplies.DC-side electrolytic capacitors are often used in single-phase converters to eliminate DC-side current ripple,but electrolytic capacitors have problems of large size,short life,and large losses.Therefore,the active power decoupling technology using thin-film capacitors has aroused more and more attention from researchers.Based on the new power decoupling topology proposed previously in our team work,this paper proposes a new control strategy and other new power decoupling topologies,and performs algorithm optimization design to facilitate the active use of active power decoupling technology in the fields of photovoltaics,energy storage batteries,etc.The main work and innovations are as follows:1.This paper first summarizes four generally applicable power decoupling topology construction methods by combing existing literature.It can provide a reference for the subsequent design of new topologies.Secondly,the working principle of Boost type active power decoupling circuit proposed previously in our team work to eliminate double frequency ripple power is analyzed,and the passive device of the converter is parameterized.The simulation has successfully verified that the topology has the functions of boost and power decoupling.2.Based on the existing Boost-type power decoupling circuit proposed previously in our team work,this paper proposes a control algorithm to realize reactive power and power decoupling control at the same time,and the parameter optimization is designed at the scenario of reactive operation.Calculations show that when considering reactive power control,the decoupling capacitor capacitance should be increased by 8.3%,so that the topology can be applied in the field of energy storage batteries,making it a distributed energy source to respond to future smart grid scheduling commands.3.From the perspective of topology,a new type of Buck active power decoupling topology is constructed in this paper,in which large-capacity electrolytic capacitors can be replaced with thin-film capacitors with smaller value of capacitance and longer life to realize power decoupling.In the designed 3k W inverter,the 2m F capacitor required by the traditional single-phase full-bridge inverter is reduced to 330μF.This topology can be applied in situations where the DC voltage level is high,and the required voltage of the devices is low.By modifying the control algorithm,the Buck-type power decoupling circuit can also achieve reactive power control.4.A RT-LAB-based hardware-in-the-loop simulation platform is built,combined with hardware-in-the-loop and DSP technology,and the comparative analysis verifies the effectiveness of the proposed new power decoupling topology and the feasibility of the proposed reactive power control strategy.By constructing a small power singlephase inverter physical platform,the effectiveness of Boost-type power decoupling topology is verified.