This paper presents the design of a robust proportional integral derivative (PID) controller for the control of a single phase microgrid voltage. A microgrid consists of loads, distributed generation units and several power‐electronics interfaced LC filter and voltage source inverter. These loads are unknown and parameters are uncertain which produce unmodeled load dynamics. This unmodeled load dynamics reduces the voltage tracking performance of the microgrid. The proposed controller gives the robustness of the system with unmodeled load dynamics. Under different kinds of uncertainties, PID controller guarantees the stability and provides zero steady‐state error and fast transient response. The robustness and optimal performance of the controller is obtained by using linear matrix inequality approach. The performance of the controller under different uncertainties is studied. Results indicate the robustness and high voltage tracking performance of the microgrid system.
This paper proposes a high-performance and robust linear quadratic regulator-proportional integral derivative (LQR-PID) controller for frequency regulation in a two-area interconnected smart grid with a population of plug-in hybrid electric vehicles. Controller robustness is achieved using a linear matrix inequality approach. The proposed control framework is tested in a simulated two-area interconnected smart grid integrated with plug-in hybrid electric vehicles under load disturbances and wind power fluctuations. The performance of the proposed controller is simulated using Matlab and compared with that of a conventional linear quadratic regulator controller. Simulation results show that the proposed controller provides reliable smart grid frequency control.INDEX TERMS Smart grid, frequency control, linear matrix inequality.
Recently, InGaN grown on semipolar and non-polar orientation has caused special attraction due to reduction in the built-in polarization field and increased confinement of high energy states compared to traditional polar c-plane orientation. However, any widespread-accepted report on output power and frequency response of the InGaN blue laser in non-c-plane orientation is readily unavailable. This work strives to address an exhaustive numerical investigation into the optoelectronic performance and frequency response of In0.17Ga0.83N/GaN quantum well laser in polar (0001), non-polar (101¯0) and semipolar (101¯2), (112¯2) and (101¯1) orientations by working out a 6 × 6 k.p Hamiltonian at the Γ-point using the tensor rotation technique. It is noticed that there is a considerable dependency of the piezoelectric field, energy band gap, peak optical gain, differential gain and output power on the modification in crystal orientation. Topmost optical gain of 4367 cm−1 is evaluated in the semipolar (112¯2)-oriented laser system at an emission wavelength of 448 nm when the injection carrier density is 3.7 × 1018 cm−3. Highest lasing power and lowest threshold current are reported to be 4.08 mW and 1.45 mA in semipolar (112¯2) crystal orientation. A state-space model is formed in order to achieve the frequency response which indicates the highest magnitude (dB) response in semipolar (112¯2) crystal orientation.
Crystalline La doped Cu-Zn ferrite with compositions Cu0.15Zn0.85LaxFe2-xO4 [ x = 0.00, 0.02, 0.04, 0.06 and 0.08] were synthesized by using conventional solid state reaction method technique. X-ray diffraction pattern (XRD),
Crystalline La doped Cu-Zn ferrite with compositions Cu0.15Zn0.85LaxFe2-xO4 [x = 0.00, 0.02, 0.04, 0.06 and 0.08] were synthesized by using conventional solid state reaction method technique. X-ray diffraction pattern (XRD), scanning electron micrographs (SEM), hysteresis loop (M-H) curves and frequency dependent resistivity were employed to inspect the effect of La3+ doping on the structure, microstructure, magnetic and transport properties of the specimens. All the specimens exhibited fcc type cubic spinel structure where the particle size were within 500-1600 nm range. Magnetically ferromagnetic phenomenon was found for all the samples where the effect of La3+ doping consequence on the variation of various parameters like saturation magnetization (Ms), coercivity (Hc) and remanent magnetization (Mr). The resistivity tuned by frequency for all the samples presented the decreasing phenomenon with the increase of applied frequency.
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