| With the rapid development of distributed new energy,more and more distributed power sources are connected to the power grid on the platform of microgrid.Renewable energy not only contributes to the protection of the environment,but also increases the pressure of voltage regulation and frequency regulation of the power grid.As the interface between distributed generation and microgrid,the operation and control of microgrid grid-connected inverter is the key to maintain the stability of microgrid.Aiming at the disadvantages of poor dynamic performance of traditional grid-connected inverter control strategy,the operation and control of microgrid are studied in this paper.Taking the dispatchable virtual oscillator control as the core,a microgrid based on the dispatchable virtual oscillator is built.The coordinated control strategy of microgrid is analyzed,and the seamless switching control strategy of microgrid based on the dispatchable virtual oscillator control is proposed.Firstly,aiming at the disadvantages of droop control grid-connected inverter,combined with the idea of virtual oscillator,a virtual oscillator control grid-connected inverter is designed.Virtual oscillator control is a nonlinear time domain controller.Compared with droop control or virtual synchronous generator control,it has a faster primary control response in islanded microgrid.Although it has superior performance,the use of VOC is limited due to the lack of secondary regulation ability.Then,aiming at the problem that the virtual oscillator control lacks the ability of secondary regulation,the inverter control method of dispatchable virtual oscillator control is designed,and its inherent droop characteristics are analyzed.Dispatchable virtual oscillator control only needs local measurement to induce voltage support behavior with programmable droop characteristics.The dispatchable virtual oscillator control is dispatchable,that is,the inverter can change its power generation by user-defined power settings to ensure strong stability.Finally,from the perspective of inverter coordinated control,a master-slave microgrid based on dispatchable virtual oscillator control is built.In the grid-connected operation of microgrid,the master-slave inverter adopts constant power control,while the master inverter adopts dispatchable virtual oscillator control while the slave inverter adopts constant power control.MATLAB/Simulink is used to build the relevant model to verify the stability of the microgrid voltage and frequency controlled by the dispatchable virtual oscillator with master-slave structure.The seamless switching control strategy of microgrid based on dispatchable virtual oscillator control is designed.Through simulation verification,the voltage and current impulse suppression of microgrid based on dispatchable virtual oscillator control is realized. |
