Xiaofeng Zhang

Dr. Xiaofeng Zhang


Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 January 2016 in Chemistry of Materials
Verified
Journal Article
Closed access
PYPengfei Yan
Pengfei Yan
JZJianming Zheng
Jianming Zheng
XZXiaofeng Zhang
Xiaofeng Zhang
RXRui Xu
Rui Xu
KAKhalil Amine
Khalil Amine
CWChong-Min Wang
Chong-Min Wang

8 July 2014 in ChemSusChem
Verified
Journal Article
Closed access
PDF file
RXRui Xu
Rui Xu
XZXiaofeng Zhang
Xiaofeng Zhang
CYCun Yu
Cun Yu
YRYang Ren
Yang Ren
JLJames C. M. Li
James C. M. Li
IBIlias Belharouak
Ilias Belharouak

18 March 2019 in IEEE Transactions on Power Electronics
Verified
Journal Article
Closed access
XZXiaofeng Zhang
Xiaofeng Zhang
RMRun Min
Run Min
DLDian Lyu
Dian Lyu
DZDonglai Zhang
Donglai Zhang
YWYi Wang
Yi Wang
YGYu Gu
Yu Gu
Digital Peak Current Mode (DPCM) control is widely used for DC-DC converters operating in Continuous Current Mode (CCM). However, Current Tracking Delay (CTD) in the system is normally neglected in the modelling stage, which leads to poor compensator design and degraded performance. This paper investigates CTD effect in boost converter with different DPCM controls. Based on dynamic relationship between the reference current and actual inductor current, the CTD transfer functions are derived, which improves the accuracy of Small Signal Model (SSM). Since CTD degrades the phase margin of the system, equivalent migration of Right Half Plane (RHP) zero is proposed to model CTD effect. This method is very simple and straightforward, which facilitates the compensator design. Furthermore, two novel DPCM control strategies with minimized CTD are proposed, and they are based on duty cycle restriction and duty cycle extension, respectively. Both controls greatly reduce the CTD effect and improve the response speed. Besides, the duty cycle extension benefits from an Extended Pulse Width Modulation (ExPWM). This optimizes the calculation algorithm and speed, while improves the time margin for digital calculations. Combined with the proposed models and controls, the CTD effect is greatly reduced. The effectiveness is verified through detailed simulations and experiments.

1 May 2022 in Advanced Intelligent Systems
Verified
Journal Article
Open access
FCFuxi Cai
Fuxi Cai
SYShe-Hwa Yen
She-Hwa Yen
AUApurva Uppala
Apurva Uppala
LTLuke Thomas
Luke Thomas
TLTianchi Liu
Tianchi Liu
BABuvna Ayyagari-Sangamalli
Buvna Ayyagari-Sangamalli
As the demands of big data applications and deep learning continue to rise, the industry is increasingly looking to artificial intelligence (AI) accelerators. Analog in‐memory computing (AiMC) with emerging nonvolatile devices enable good hardware solutions, due to its high energy efficiency in accelerating the multiply‐and‐accumulation (MAC) operation. Herein, an Applied Materials custom‐designed system‐on‐chip (SoC) targeting AI applications with analog in‐memory computing using resistive random‐access memory (ReRAM) as the compute element is demonstrated. The first silicon achieves high energy efficiency in MAC operations. This chip is implemented with LeNet‐1 neural network on ReRAM tiles and demonstrated by Modified National Institute of Standards and Technology (MNIST) classification with accuracy matching that predicted in the simulations. A simulation framework, AI Sim, is also developed to evaluate the system performance for large‐scale application and guide the bitcell development and design choices.

1 April 2008
Verified
Conference Paper
Closed access
FYFei Yu
Fei Yu
XZXiaofeng Zhang
Xiaofeng Zhang
MQMinzhong Qiao
Minzhong Qiao
CDChengdong Du
Chengdong Du
The mathematical models of five-phase permanent magnet synchronous motor (PMSM) in abc frame and alphabeta frame are established, and the relationships between the torque and fundamental components, loss and harmonic components are revealed. To suppress the high third harmonic current appeared in five-phase machine especially, a novel space vector pulse width modulation (SVPWM) method which has a feature of low harmonic is proposed. The proposed method is adopted to implement the direct torque control (DTC) of a five-phase PMSM, and a good torque and current performance are got and validated by simulation and experiment.

13 December 2018 in Energies
Verified
Journal Article
Open access
PDF file
XZXiaofeng Zhang
Xiaofeng Zhang
RMRun Min
Run Min
DZDonglai Zhang
Donglai Zhang
YWYi Wang
Yi Wang
This paper presents an Optimized Sensorless Charge Balance (OSCB) controller based on a damped current model for flyback converter operating in Discontinuous Conduction Mode (DCM). By solving total differential equations of non-ideal transformer currents, the damped current model is derived with consideration of parasitics, leakage inductance of transformer, and the Resistor-Capacitor-Diode (RCD) snubber circuit. Based on the proposed model, current observation and control algorithms of the Sensorless Charge Balance (SCB) controller are optimized, which forms the OSCB control strategy. The average current damping is considered in the equivalent discrete-time small signal model. Furthermore, frequency analyses show that OSCB controller achieves higher closed-loop bandwidth and lower overshoot than a SCB controller, which indicates an improved transient performance. Finally, both OSCB and conventional SCB controllers are experimentally evaluated on a flyback converter prototype.