Real Time Implementation of Multilevel Converter based Shunt Active Power Filter for Harmonic Compensation in Distribution System
2016 7TH INDIA INTERNATIONAL CONFERENCE ON POWER ELECTRONICS (IICPE)
Authors: Tandekar, Jitendra; Ojha, Amit; Jain, Shailendra
Abstract
In past few years, with an increasing usage of power electronic devices in industries as well as distribution systems, the power quality is constantly depreciating. This paper investigation on mitigation of current harmonics, thereby improves power quality by using seven level cascaded multilevel converters based Shunt Active Power Filter (SAPF), which consists of transformer-less Multilevel Converter (MLC). The aim of this paper is development and analysis of SAPF for harmonics compensation in distribution system for power quality improvement. It also reduces weight and cost of the system. Instantaneous active and reactive power method (p-q theory) is adapted for generation of compensation active filter current where DC link voltage is regulated by PI controller. In order to generate gating signals, multi-carrier Alternate Phase Opposition Disposition (APOD) PWM scheme is used. The proposed CHB-MLC APF reduces the source current THD below 5%. The results are simulated using MATLAB/Simulink and demonstrates the effective mitigation of current harmonics with charge balancing APOD-PWM. The performance of proposed scheme has also been validated in Real-Time, using Opal-RT OP4500 simulator for non linear load and for high voltage distribution system.
Testosterone inhibits estrogen-induced mammary epithelial proliferation and suppresses estrogen receptor expression
FASEB JOURNAL
Authors: Zhou, J; Ng, S; Adesanya-Famuiya, O; Anderson, K; Bondy, CA
Abstract
This study investigated the effect of sex steroids and tamoxifen on primate mammary epithelial proliferation and steroid receptor gene expression. Ovariectomized rhesus monkeys were treated with placebo, 17 beta estradiol (E2) alone or in combination with progesterone (E2/P) or testosterone (E2/T), or tamoxifen for 3 days. E2 alone increased mammary epithelial proliferation by similar to six-fold (P<0.0001) and increased mammary epithelial estrogen receptor (ER alpha) mRNA expression by similar to 50% (P<0.0001; ER beta mRNA was not detected in the primate mammary gland). Progesterone did not alter E2's proliferative effects, but testosterone reduced E2-induced proliferation by similar to 40% (P<0.002) and entirely abolished E2-induced augmentation of ER alpha expression. Tamoxifen had a significant agonist effect in the ovariectomized monkey, producing a similar to threefold increase in mammary epithelial proliferation (P<0.01), but tamoxifen also reduced ER alpha expression below placebo level.. Androgen receptor (AR) mRNA was detected in mammary epithelium by in situ hybridization. AR mRNA levels were not altered by E2 alone but were significantly reduced by E2/T and tamoxifen treatment. Because combined E2/T and tamoxifen had similar effects on mammary epithelium, we investigated the regulation of known sex steroid-responsive mRNAs in the primate mammary epithelium. E2 alone had no effect on apolipoprotein D (ApoD) or IGF binding protein 5 (IGFBP5) expression, but E2/T and tamoxifen treatment groups both demonstrated identical alterations in these mRNAs (ApoD was decreased and IGFBP5 was increased). These observations showing androgen-induced down-regulation of mammary epithelial proliferation and ER expression suggest that combined estrogen/androgen hormone replacement therapy might reduce the risk of breast cancer associated with estrogen replacement. In addition, these novel findings on tamoxifen's androgen-like effects on primate mammary epithelial sex steroid receptor expression suggest that tamoxifen's protective action on mammary gland may involve androgenic effects.