The Experts below are selected from a list of 624372 Experts worldwide ranked by ideXlab platform
Yanfei Liu - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Performance improvement of diode capacitor based high step up dc dc converter through right half plane zero elimination
2017Co-Authors: Yan Zhang, Jinjun Liu, Zhuo Dong, Hongliang Wang, Yanfei LiuAbstract:Diode–capacitor-based dc–dc converters provide a simple and low cost solution for high step-up voltage regulation in solar and fuel cell generation. Transient modeling analysis reveals their worse influence of nonlinear and nonminimum-phase system characteristic due to right-half-plane (RHP) zero, especially in high voltage gain application. However, the process of energy transfer for diode–capacitor-based dc–dc converter is different from basic dc–dc converter. Based on the unique feature, this paper proposes an improved main circuit structure with parallel connection of resistive–capacitive damping network across the intermediate capacitor to achieve good Dynamic Performance. By optimal parameter design according to Routh–Hurtwitz criterion, all the RHP zeros in the transfer function of control-to-output voltage are eliminated completely. Then, by the case of diode–capacitor-based boost converter, the adaptive PI controller is designed to deal with nonlinear characteristic of voltage gain. It gets good Dynamic Performance under wide range output voltage. All the theoretical findings and design approaches are verified by simulation and experiment results. The existing diode–capacitor-based high step-up dc–dc converters with slight main circuit modification are more promising in renewable energy application.
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a new digital control algorithm to achieve optimal Dynamic Performance in dc to dc converters
2007Co-Authors: Guang Feng, E Meyer, Yanfei LiuAbstract:In this paper, a new control algorithm is proposed to achieve optimal Dynamic Performance for dc-to-dc converters under a load current change and for a given set of circuit parameters, such as the output inductor, output capacitor, switching frequency, input voltage, and output voltage. Using the concept of capacitor charge balance, the proposed algorithm predicts the optimal transient response for a dc-to-dc converter during a large signal load current change. During steady state operation, conventional current mode proportional-integral-derivative (PID) is used. During large signal transient conditions, the new control algorithm takes over. The equations needed to calculate the transient time and the required duty cycle series are presented. By using the proposed algorithm, the optimal transient Performances, including the smallest output voltage overshoot/undershoot and the shortest recovery time, is achieved. In addition, since the large signal Dynamic response of the power converter is successfully predicted, the large signal stability is guaranteed. Experimental results show that the proposed method produces superior Dynamic Performance over a conventional current mode PID controller.
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a new robust algorithm to improve the Dynamic Performance on the speed control of induction motor drive
2004Co-Authors: Guang Feng, Yanfei Liu, Lipei HuangAbstract:A nonlinear auto-disturbance rejection controller (ADRC) has been developed to ensure high Dynamic Performance of induction motors in this paper. By using the extended state observer (ESO), ADRC can accurately estimate the derivative signals and precise decoupling of induction motors is achieved. In addition, the proposed strategy realizes the disturbance compensation without accurate knowledge of induction motor parameters. The simulation and experimental results show that the proposed controller ensures good robustness and adaptability under modeling uncertainty and external disturbance. It is concluded that the proposed topology produces better Dynamic Performance, such as small overshoot and fast transient time, than the conventional proportional/integral/derivative (PID) controller in its overall operating conditions.
Donglai Zhang - One of the best experts on this subject based on the ideXlab platform.
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high power high Dynamic Performance space solar array simulator using step wave tracking output voltage approach
2018Co-Authors: Donglai Zhang, Lu Qu, Xiaofeng Zhang, Yu GuAbstract:With the power of high-orbit satellites now reaching dozens of kilowatts, solar energy sources play an important role in nonterrestrial applications. However, most of the existing high-power solar array simulators (SASs) are designed for simulating energy sources in terrestrial applications, and may not have suitable Dynamic Performance for nonterrestrial applications. This paper proposes a design for a high-power high-Dynamic-Performance space solar array simulator (SSAS) system, which combines a linear power stage unit and a multilevel bus tracking converter unit, in order to achieve a fast step-switching capability and high-power-handling capacity. In this paper, we consider the SSAS power system as two separate parts: the I–V power curve simulator that uses a linear power stage with 20 linear voltage-controlled current paths in parallel; and the multilevel bus tracking converter unit that provides the variable voltage levels tracking the SSAS output voltage, in order to decrease the power dissipation in the linear power stage. This paper establishes a mathematical model for the multilevel converter under this particular system architecture, and presents the application qualification conditions and system design principles. The proposed 2.4-kW SSAS can react quickly to a load step between the short-circuit and open-circuit states, which are the most challenging working conditions, at a stepping frequency of 3 kHz; this is a superior Dynamic Performance compared to other similar devices. The experimental results of testing the spacecraft power supply with a shunt regulator architecture demonstrating better Performance, when compared to the results from four SAS modular products in parallel.
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high Dynamic Performance solar array simulator based on a sic mosfet linear power stage
2018Co-Authors: Donglai ZhangAbstract:The power conditioning unit system is a critical part in a spacecraft and is responsible for converting the solar panel energy into a stable bus voltage. This system requires a high Dynamic characteristic solar array simulator (SAS) for testing purposes. Space solar array simulators (SSASs) used for testing space power systems generally use a linear power topology because of its fast Dynamic Performance and good simulation accuracy. However, commercially available SASs are not sufficiently fast for simulating the actual solar array panel output and, therefore are unreliable for terrestrial testing. In this paper, a highly Dynamic SSAS is developed with multipath SiC MOSFET linear voltage-controlled current source paralleling for power regulation. The proposed 510 W SSAS, consisting of 20 linear current paths paralleling the power stage and a high-speed FPGA digital controller, can quickly react to a load step between the nominal and short circuit at 50-kHz stepping frequency. It can also react to a step change from a short circuit to an open circuit perfectly at a 1-kHz stepping frequency offering a superior Dynamic Performance compared to other similar devices.
Herbert Haunstein - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Performance Evaluation of Optical Polarization Mode Dispersion Compensators and Electronic Equalizers Including Forward Error Correction
2008Co-Authors: Dieter Werner, Herbert Haunstein, Sethumadhavan ChandrasekharAbstract:A method to test the Dynamic Performance of polarization mode dispersion (PMD) compensators (PMDCs) is presented. The Dynamic Performance of an optical PMDC combined with electronic equalizers is measured before and after forward error correction.
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Dynamic Performance and speed requirement of polarization mode dispersion compensators
2006Co-Authors: Chongjin Xie, Dieter Werner, Herbert HaunsteinAbstract:To study the Dynamic Performance of a polarizationmode-dispersion compensator (PMDC), a continuous PMD model and a Dynamic PMDC model are presented. The continuous PMD model generates continuous PMD and state of polarization (SOP) variations. The statistics of the SOP variation generated by the continuous PMD model follows the Rayleigh distribution, and the SOP variation amplitude scales with the square root of sampling-time interval. The results are compared with those of a numerical and a commercial polarization scrambler, and the difference of the SOP variation characteristics between the PMD model and the polarization scramblers is explained. The continuous PMD model and the Dynamic PMDC model are used to study the Dynamic Performance and speed requirement of a two-stage PMDC. The speed requirement of the PMDC is quantified in the SOP variation in one PMDC loop cycle. The authors found that when the SOP variation is within 3deg in one PMDC loop cycle, the Dynamic PMD and SOP changes virtually does not cause any degradation in the PMDC Performance
Guang Feng - One of the best experts on this subject based on the ideXlab platform.
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a new digital control algorithm to achieve optimal Dynamic Performance in dc to dc converters
2007Co-Authors: Guang Feng, E Meyer, Yanfei LiuAbstract:In this paper, a new control algorithm is proposed to achieve optimal Dynamic Performance for dc-to-dc converters under a load current change and for a given set of circuit parameters, such as the output inductor, output capacitor, switching frequency, input voltage, and output voltage. Using the concept of capacitor charge balance, the proposed algorithm predicts the optimal transient response for a dc-to-dc converter during a large signal load current change. During steady state operation, conventional current mode proportional-integral-derivative (PID) is used. During large signal transient conditions, the new control algorithm takes over. The equations needed to calculate the transient time and the required duty cycle series are presented. By using the proposed algorithm, the optimal transient Performances, including the smallest output voltage overshoot/undershoot and the shortest recovery time, is achieved. In addition, since the large signal Dynamic response of the power converter is successfully predicted, the large signal stability is guaranteed. Experimental results show that the proposed method produces superior Dynamic Performance over a conventional current mode PID controller.
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a new robust algorithm to improve the Dynamic Performance on the speed control of induction motor drive
2004Co-Authors: Guang Feng, Yanfei Liu, Lipei HuangAbstract:A nonlinear auto-disturbance rejection controller (ADRC) has been developed to ensure high Dynamic Performance of induction motors in this paper. By using the extended state observer (ESO), ADRC can accurately estimate the derivative signals and precise decoupling of induction motors is achieved. In addition, the proposed strategy realizes the disturbance compensation without accurate knowledge of induction motor parameters. The simulation and experimental results show that the proposed controller ensures good robustness and adaptability under modeling uncertainty and external disturbance. It is concluded that the proposed topology produces better Dynamic Performance, such as small overshoot and fast transient time, than the conventional proportional/integral/derivative (PID) controller in its overall operating conditions.
Wei Hua - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Performance evaluation of a nine phase flux switching permanent magnet motor drive with model predictive control
2016Co-Authors: Ming Cheng, K T Chau, Wei HuaAbstract:Multiphase flux-switching permanent-magnet (FSPM) motor drives are nowadays considered for various applications due to numerous advantages when compared with their three-phase counterparts. In principle, stator-flux-oriented control of a nine-phase flux-switching permanent-magnet (FSPM) (9P-FSPM) motor can be realized theoretically by using four pairs of synchronous current controllers in conjunction with eight conventional proportional-integrals (PIs), for alleviation of the coupling effects and unwanted low-order stator current harmonics. In practice, however, drive Performance will deteriorate if the PI-based current controller is not well tuned for optimum response to every Dynamic scenario due to nonlinearity. In order to enhance Dynamic Performance of the drive system, a fully-decoupled model predictive control algorithm with fixed switching frequency is developed for the 9P-FSPM motor. The main contribution is comprehensive and detailed description of precise modeling of the 9P-FSPM motor and the controller design process. Also, some practical hints are given for implementation, such as the elimination of low-order harmonic currents and the selection of active voltage vector in the nine-phase drive system. Both simulation and experimental results are presented to validate the effectiveness of the developed current controller and the high Dynamic Performance of the 9P-FSPM motor drive.
