Performance analysis of DFIG with PI, PID and FOPID control schemes in Micro grid

Doubly Fed Induction Generator (DFIG) is the most popular variable speed wind energy conversion system. Control of the DFIG is more complicated than the control of a standard Induction motor. To control the DFIG, the rotor current is controlled by a power electronics converter. This paper aims to analyze the performance improvement of DFIG with its controllers such as proportional integral, proportional integral derivative and fractional order proportional integral derivative controllers in micro grid. Design and implementation of these controllers are done in the rotor circuit of DFIG byMATLAB simulation tool. The design, analysis, and MATLAB simulation of a constant grid power wind energy conversion system also discussed. In all abnormal conditions, the required reactive power into the grid is taken care by the horizontal axis wind turbine system. Mathematical modeling of DFIG is addressed. Independent control of active and reactive powers isachieved, and different simulation results under loaded conditions, with variation in prime mover speed and Excitation are presented. The simulation results of the proposed system are discussed with the cases such as transient, post transient conditions, variation of wind speed, fluctuation of electromagnetic torque, active and reactive powers, grid voltage and load contribution of DFIG with its controllers in grid. Based on the extensive simulation results, what type of control scheme givesthe effective performance of DFIG in grid is finally concluded. The performances of PID and FOPID controllers are compared with that of PI controller at the end. It is seen that, the closed loop performance of FOPID controller outperforms as compared to conventional controllers

Improved Performance of DPFC Using Sliding Mode Controller Method

Modern power systems demand the need of active power flow with the help of Power Electronics control devices is needed. In the family of Flexible AC Transmission devices (FACTS), Dynamic PFC (DPFC) offers the same controlling function as Unified PFC (UPFC), comprising the control of transmission angle, bus voltage and line impedance. A technical modification of UPFC is DPFC in which fluctuations of voltage at DC link is eliminated that enables the individual operation as series and parallel controllers. The concept of DFACTS is used in design of the series converter. The replacement of  the  high  rating  three  phase  series  converter with  the multiple low rating single phase converters results in cost reduction and increases reliability greatly. This DC Link is used to transfer the real power between two converters in UPFC such as in DPFC which eliminates the 3rd harmonic frequencies at transmission lines. D-FACTS converters are acting as insulation between high voltage phases acts as 1-ᴓ floating with respect to ground. These results in lower cost for the DPFC system compared to the UPFC. This paper describes the comparison of PI and Sliding Mode Controllers which conclude that SMC is a better control strategy compared to PI

DPFC Performance with the Comparison of PI and ANN Controller

Modern power systems demand the active control of power flow and for this purpose Power flow controlling devices (PFCDs) are required. Distributed FACTS Controller (DPFC) is a part of FACTS family. DPFC offers equal control ability same as UPFC, comprising the adjustment of the internal angle of the machine and bus voltage includes line impedance. In addition to UPFC a new device evolved known as DPFC in which common DC link is eliminated that enables the exclusive working between the two converters which are shunt and the series. The Distributed-FACTS (D- FACTS) idea is adopt in the series converter scheme. The replacement of the high rating three phase series converter  with the multiple low rating single phase converters results in cost reduction and increases reliability greatly. The useful power transfer between the two converters which are shunt and series through common dc link in UPFC where as in DPFC in this the required power is transferred in the transmission line with three times of natural fundamental frequency. Where as in the new device no need of large voltage separation between the line and PFC Device is no requirement of high voltage isolation between because D-FACTS converters which are 1-ᴓ floating device with respect to the ground. Accordingly, In this paper we bring out the DPFC performance differences with different control techniques which are PI and Artificial Neural Network Controllers and bring with conclusion that ANN is a better control strategy compared to PI

Grid-Connected Rectifier Based Dynamic Voltage Restorer To Improve Power Quality By Compensating Voltage Sag And Swell

Voltage sag and voltage swell are frequently occurred power quality problems in present power distribution system, which are cause more problems to avoid these problems and maintain constant voltage at sensitive load during sag and swell Dynamic voltage restorer gives solution .we propose self-supported DVR, to minimize the cost by preventing external dc source in DVR, it is controlled by SRF PI control along with an inner current loop to stabilize the system and outer voltage loop to increase the system robustness. The proposed model provides fast voltage restoration for a short and long duration of voltage sags and swells manage wide load current variation for short and long voltage disturbances. In this paper, we present the effectiveness of the proposed method by using MATLAB/simulation results. A laboratory prototype DVR is modelled and we are using CCS studio to interface DSPTMS320F28027

An Efficacious Modulation Gambit Using Fewer Switches in a Multilevel Inverter

Since multicarrier based modulation techniques are simple to implement and can be used to control inverters at any level, they are frequently employed in modern multilevel inverters in high or medium power applications. When considering the many multi-carrier modulation techniques available, level-shifted pulse-width modulation (LSPWM) is often chosen for its superior harmonic performance. However, this traditional LSPWM method is not suitable for controlling newly proposed reduced switch count (RSC) MLI topologies. The research work in this paper seeks to elucidate the reasons why conventional LSPWM is ineffective in controlling RSC MLI topologies, and proposes a generalized LSPWM system based on logical expressions. The proposed method can be utilized with symmetrical and asymmetrical RSC MLIs, and can be extended to an arbitrary number of levels. The merit of the proposed method for controlling any RSC configuration with satisfactory line-voltage THD (≈1.8%) performance (identical to conventional LSPWM) was evaluated using multiple 13-level asymmetrical RSC-MLI topologies. A MATLAB model was developed and then subjected to simulation and real-world testing to prove the effectiveness of the proposed modulation strategy

Reducing acetylated tau is neuroprotective in brain injury

Traumatic brain injury (TBI) is the largest non-genetic, non-aging related risk factor for Alzheimer’s disease (AD). We report here that TBI induces tau acetylation (ac-tau) at sites acetylated also in human AD brain. This is mediated by S-nitrosylated-GAPDH, which simultaneously inactivates Sirtuin1 deacetylase and activates p300/CBP acetyltransferase, increasing neuronal ac-tau. Subsequent tau mislocalization causes neurodegeneration and neurobehavioral impairment, and ac-tau accumulates in the blood. Blocking GAPDH S-nitrosylation, inhibiting p300/CBP, or stimulating Sirtuin1 all protect mice from neurodegeneration, neurobehavioral impairment, and blood and brain accumulation of ac-tau after TBI. Ac-tau is thus a therapeutic target and potential blood biomarker of TBI that may represent pathologic convergence between TBI and AD. Increased ac-tau in human AD brain is further augmented in AD patients with history of TBI, and patients receiving the p300/CBP inhibitors salsalate or diflunisal exhibit decreased incidence of AD and clinically diagnosed TBI.[Display omitted]•Brain injury induces Alzheimer’s disease-like neuronal ac-tau•Neurodegenerative brain injury is reflected by ac-tau blood levels in mice and people•Decreasing ac-tau after brain injury at multiple signaling nodes is neuroprotective•Ac-tau-inhibiting medicines are associated with reduced neurodegenerative diseaseReducing brain injury-induced neuronal tau acetylation is neuroprotective in traumatic brain injury and has a role in Alzheimer’s disease pathogenesis

Comparison of bivalent and monovalent SARS-CoV-2 variant vaccines: the phase 2 randomized open-label COVAIL trial.

Vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection wanes over time, requiring updated boosters. In a phase 2, open-label, randomized clinical trial with sequentially enrolled stages at 22 US sites, we assessed safety and immunogenicity of a second boost with monovalent or bivalent variant vaccines from mRNA and protein-based platforms targeting wild-type, Beta, Delta and Omicron BA.1 spike antigens. The primary outcome was pseudovirus neutralization titers at 50% inhibitory dilution (ID50 titers) with 95% confidence intervals against different SARS-CoV-2 strains. The secondary outcome assessed safety by solicited local and systemic adverse events (AEs), unsolicited AEs, serious AEs and AEs of special interest. Boosting with prototype/wild-type vaccines produced numerically lower ID50 titers than any variant-containing vaccine against all variants. Conversely, boosting with a variant vaccine excluding prototype was not associated with decreased neutralization against D614G. Omicron BA.1 or Beta monovalent vaccines were nearly equivalent to Omicron BA.1 + prototype or Beta + prototype bivalent vaccines for neutralization of Beta, Omicron BA.1 and Omicron BA.4/5, although they were lower for contemporaneous Omicron subvariants. Safety was similar across arms and stages and comparable to previous reports. Our study shows that updated vaccines targeting Beta or Omicron BA.1 provide broadly crossprotective neutralizing antibody responses against diverse SARS-CoV-2 variants without sacrificing immunity to the ancestral strain. ClinicalTrials.gov registration: NCT05289037