The power quality of new energy resources has received tremendous attention recently. The control approach for the inverter, an interface between the new energy resources, and the infinite bus system is of vital importance. For the virtual synchronous generator (VSG), one of the research hotspots in the inverter control field, there are some challenges remaining to be dealt with. First is the contradiction between the rapid response and overshoot of active power output if VSG is connected to the grid. Secondly, the active power is deeply influenced by the fluctuation of gird frequency and this may bring power oscillation to VSG in weak grids. In this article, an active power controller for power tracking of grid-connected VSG is designed based on linear active disturbance rejection control (LADRC) by compensating for the lumped disturbance in a feedforward fashion. The parameters of the controller are analyzed and tuned in the frequency domain to acquire a desirable control performance. Moreover, the robustness of the control system is also considered. Simulation results show that the designed control system can transmit active power to the grid in a timely manner with no overshoot, as demanded. Additionally, it can output active power steadily according to the power reference without using a phase-locked loop (PLL) when the grid frequency has different features of fluctuation. In addition, the simulation results demonstrate that the improved VSG has strong robustness to the model parameter perturbation and mismatch.

It is urgent to study a new control system for improving the efficiency of electrostatic precipitator. The System-on-a-Programmable-Chip (SOPC) development board, which belongs to the series of Cyclone of Altera Company, is used as the development platform. Analog Digital (AD) conversion module, voltage control module and overall control module of the electrostatic precipitator are designed and the simulation waveform of the system is analyzed, based on the programmable logic device EP1C12Q240C6 and Very-High-Speed Integrated Circuit Hardware Description Language (VHDL) programming language. The results show that: by using Field Programmable Gate Array (FPGA) as the control, transformation of AD is accurate and fast and high voltage power supply is stable, which leads to a certain value for generalization.