Duty Ratio Predictive Control Scheme for Digital Control of DC-DC Switching Converters

Pengju Sun,Luowei Zhou 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.2

The control loop time delay caused by sampling, the zero-order-holder effect and calculations is inevitable in the digital control of dc-dc switching converters. The time delay will limit the bandwidth of the control loop and therefore degrade the transient performance of digital systems. In this paper, the quantization time delay effects with different time delay values based on a generic second-order system are analyzed. The conclusion that the bandwidth of digital control is reduced by about 20% with a one cycle delay and by 50% with two cycles of delay in comparison with no time delay is obtained. To compensate the time delay and to increase the control loop bandwidth, a duty ratio predictive control scheme based on linear extrapolation is proposed. The compensation effect and a comparison of the load variation transient response characteristics with analogy control, conventional digital control and duty ratio predictive control with different time delay values are performed on a point-of-load Buck converter by simulations and experiments. It is shown that, using the proposed technique, the control loop bandwidth can be increased by 50% for a one cycle delay and 48.2% for two cycles of delay when compared to conventional digital control. Simulations and experimental results prove the validity of the conclusion of the quantization effects of the time delay and the proposed control scheme.

BSDEs on finite and infinite time horizon with discontinuous coefficients

Pengju Duan,Yong Ren 대한수학회 2013 대한수학회보 Vol.50 No.4

This paper is devoted to solving one dimensional backward stochastic differential equations (BSDEs). We prove the existence of the solutions to BSDEs if the generator satisfies the general growth and discontinuous conditions.

Cohomology of torsion and completion of $N$-complexes

Pengju Ma,Xiaoyan Yang 대한수학회 2022 대한수학회지 Vol.59 No.2

We introduce the notions of Koszul $N$-complex, $\check{\mathrm{C}}$ech $N$-complex and telescope $N$-complex, explicit derived torsion and derived completion functors in the derived category $\mathbf{D}_N(R)$ of $N$-complexes using the $\check{\mathrm{C}}$ech $N$-complex and the telescope $N$-complex. Moreover, we give an equivalence between the categories of cohomologically $\mathfrak{a}$-torsion $N$-complexes and cohomologically $\mathfrak{a}$-adic complete $N$-complexes, and prove that over a commutative Noetherian ring, via Koszul cohomology, via RHom cohomology (resp. $\otimes$ cohomology) and via local cohomology (resp. derived completion), all yield the same invariant.

Duty Ratio Predictive Control Scheme for Digital Control of DC-DC Switching Converters

Sun, Pengju,Zhou, Luowei The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.2

The control loop time delay caused by sampling, the zero-order-holder effect and calculations is inevitable in the digital control of dc-dc switching converters. The time delay will limit the bandwidth of the control loop and therefore degrade the transient performance of digital systems. In this paper, the quantization time delay effects with different time delay values based on a generic second-order system are analyzed. The conclusion that the bandwidth of digital control is reduced by about 20% with a one cycle delay and by 50% with two cycles of delay in comparison with no time delay is obtained. To compensate the time delay and to increase the control loop bandwidth, a duty ratio predictive control scheme based on linear extrapolation is proposed. The compensation effect and a comparison of the load variation transient response characteristics with analogy control, conventional digital control and duty ratio predictive control with different time delay values are performed on a point-of-load Buck converter by simulations and experiments. It is shown that, using the proposed technique, the control loop bandwidth can be increased by 50% for a one cycle delay and 48.2% for two cycles of delay when compared to conventional digital control. Simulations and experimental results prove the validity of the conclusion of the quantization effects of the time delay and the proposed control scheme.

BSDES ON FINITE AND INFINITE TIME HORIZON WITH DISCONTINUOUS COEFFICIENTS

Duan, Pengju,Ren, Yong Korean Mathematical Society 2013 대한수학회보 Vol.50 No.4

This paper is devoted to solving one dimensional backward stochastic differential equations (BSDEs). We prove the existence of the solutions to BSDEs if the generator satisfies the general growth and discontinuous conditions.

ON RELATIVE COHEN-MACAULAY MODULES

Zhongkui Liu,Pengju Ma,Xiaoyan Yang Korean Mathematical Society 2023 대한수학회지 Vol.60 No.3

Let a be an ideal of 𝔞 commutative noetherian ring R. We give some descriptions of the 𝔞-depth of 𝔞-relative Cohen-Macaulay modules by cohomological dimensions, and study how relative Cohen-Macaulayness behaves under flat extensions. As applications, the perseverance of relative Cohen-Macaulayness in a polynomial ring, formal power series ring and completion are given.

Forward Matching Fusion Algorithm for PDR based on Geomagnetic Fingerprint Map

Yuke Li,Pengju Wang,Tong Li,Yinxuan Liu,Shigeyuki Tateno 제어로봇시스템학회 2022 제어로봇시스템학회 국제학술대회 논문집 Vol.2022 No.11

Aiming at the problem that indoor positioning using pedestrian dead reckoning (PDR) algorithm will lead to error accumulation and the precision of built-in sensors of smartphones is not high enough, indoor positioning research based on the fusion of geomagnetic positioning and PDR positioning algorithm is proposed. A Kriging interpolation based fusion matching algorithm was used to construct geomagnetic fingerprint map to reduce the time spent in data sampling. The fusion positioning is realized by combining the PDR positioning with the hybrid matching algorithm of lattice matching and sequence matching. The improved algorithm solves the problems of global search for geomagnetic sequence matching and PDR positioning error accumulation in traditional methods, improves the positioning accuracy and solves the problems that through the wall or even out of the map caused by the error accumulation. Experimental results show that the maximum positioning error of the proposed algorithm is less than 1m in the complex movement of 120 steps for 60m. The probability of positioning accuracy less than 0.5m is 85%. This can meet the needs of ordinary indoor positioning.

PEDOT-PSS-Coated FeFe(CN)6 Composite Cathode for Lithium-ion Batteries with the Improved Electrochemical Performances

Lihuan Xu,Jiaojiao Ma,Pengju Guo,Chang Su 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.9

Prussian-blue type FeFe(CN)6 nanocrystals with perfect nanocubic morphology were prepared by a facile hydrolytic precipitation method using Fe(CN)3- 6 as a single iron-source. The resulting FeFe(CN)6 nanocrystals have subsequently been encapsulated within a mixed electronically and ionically conducting polystyrene sulfonic acid (PSS)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) (PEDOT-PSS) with ethylene glycol (EG) as the polar solvent to obtain a high electrical conducting organic–inorganic nanohybrid. The FeFe(CN)6/PEDOT-PSS nanohybrid offers discharge capacity of 106.3 mAh · g -1, which is improved compared to that of the naked FeFe(CN)6(94.4 mAh · g -1). Also, it demonstrated the improved capacity retention and rate capability, which makes it a promising way for high performance Li-ion batteries for energy storage application.

p53 overexpression represses androgen-mediated induction ofNKX3.1 in a prostate cancer cell line

Anli Jiang,Chunxiao Yu,Pengju Zhang,Weiwen Chen,Wenwen Liu,Xiaoyan Hu,Jianye Zhang 생화학분자생물학회 2006 Experimental and molecular medicine Vol.38 No.6

Prostate cancer is a disease involving complicated multiple-gene alterations. Both NKX3.1 and p53 are related to prostate cancer and play crucial roles in prostate cancer progression. However, little is known about the relationships and interactions between p53 and NKX3.1 in prostate cancer. We found that NKX3.1 expression is down-regulated by over-expression of wild type (wt) p53 in prostate cancer LNCaP cells. NKX3.1 is down-regulated at both the mRNA and protein levels by p53 overexpression due to either transient transfection of exogenous p53 or induction of endogenous p53. p53 over-expression represses androgen-induced transactivation of NKX3.1 by inhibiting the promoter of the androgen acceptor (AR) gene and by blocking AR-DNA binding activity. In addition, transfection with the p21 expression vector (pPSA-p21) showed that p21 does not reduce NKX3.1 expression, indicating that NKX3.1 expression is not the result of nonspecific effects of cell growth arrest. Our results provide biochemical and cellular biologic evidence that NKX3.1 is down-regulated by p53 over-ex - pression in prostate cancer cells.

Effects of Astragalus membranaceus roots supplementation on growth performance, serum antioxidant and immune response in finishing lambs

Hao, Xiaoyan,Wang, Pengju,Ren, Youshe,Liu, Gentang,Zhang, Jianxin,Leury, Brian,Zhang, Chunxiang Asian Australasian Association of Animal Productio 2020 Animal Bioscience Vol.33 No.6

Objective: Astragalus membranaceus root is a well-known traditional Chinese herbal medicine with many biological active constituents. This study was conducted to examine the effects of Astragalus membranaceus root powder (AMP) on growth performance, serum antioxidant and immune response in finishing lambs. Methods: A total of thirty-six Guangling fat-tailed ram lambs (body weight = 19±2 kg, mean±standard deviation) were randomly assigned to one of six treatments for a 40 d feeding period, with the first 10 d for adaptation. Treatments consisted of the lambs' basal diets with addition of 0, 5, 10, 15, 20, and 30 g/kg of diet of AMP. Results: Response to supplementation level of AMP was quadratic (p≤0.032) for final weight and ADG with the greatest at 10 g/kg of diet, but dry matter intake was not affected (p≥0.227) by treatments. The increase of AMP supplementation resulted in a quadratic response in contents of triglyceride and creatinine (p<0.05), with the lowest values for 10 and 20 g/kg of diet, respectively. A linear and quadratic decrease was observed in activity of alkaline phosphatase in serum of lambs. As the AMP supplementation increased, the activities of total superoxide dismutase and total antioxidant capacity increased linearly (p≤0.018) and hydroxyl radical (OH^-) decreased linearly (p = 0.002). For catalase (CAT) and malondialdehyde (MDA), quadratic (p≤0.001) effects were observed among treatments, with the greatest CAT and lowest MDA values at 10 g/kg AMP. Additionally, supplementing AMP up to a level of 10 or 15 g/kg of diet quadratically increased immunoglobulin and interleukin contents in the serum. Conclusion: The results indicated that AMP can be used as natural feed additive in the ration of lambs to improve ADG, antioxidant status, and immune functions, and the optimal dose was 10 g/kg of diet under the condition of this experiment.