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Du, Guiping,Liu, Zhifei,Du, Fada,Li, Jiajian The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
This paper proposes a model predictive control based on the discrete Lyapunov function to improve the performance of power electronic converters. The proposed control technique, based on the finite control set model predictive control (FCS-MPC), defines a cost function for the control law which is determined under the Lyapunov stability theorem with a control error compensation. The steady state and dynamic performance of the proposed control strategy has been tested under a single phase AC/DC voltage source rectifier (S-VSR). Experimental results demonstrate that the proposed control strategy not only offers global stability and good robustness but also leads to a high quality sinusoidal current with a reasonably low total harmonic distortion (THD) and a fast dynamic response under linear loads.
Guiping Du,Zhifei Liu,Fada Du,Jiajian Li 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
This paper proposes a model predictive control based on the discrete Lyapunov function to improve the performance of power electronic converters. The proposed control technique, based on the finite control set model predictive control (FCS-MPC), defines a cost function for the control law which is determined under the Lyapunov stability theorem with a control error compensation. The steady state and dynamic performance of the proposed control strategy has been tested under a single phase AC/DC voltage source rectifier (S-VSR). Experimental results demonstrate that the proposed control strategy not only offers global stability and good robustness but also leads to a high quality sinusoidal current with a reasonably low total harmonic distortion (THD) and a fast dynamic response under linear loads.
Du Baohong,Shi Fengling,Gao Guiping,Cai Liyan 한국초지조사료학회 2009 한국초지조사료학회 학술대회논문집 Vol.2009 No.08
The root crown of forage legume is an important organ which connects underground root system and aboveground branches. And its morphological characteristic is closely related to yield of grass, overwintering ability, regeneration in spring and sustainable productivity of Medicago sativa L. Therefore, in order to understand the morphological mechanism on cold resistance of the root of Melilotoides ruthenica (L.) Sojak t㏊t is a relative species of M sativa, the root morphology of different growth years' M ruthenica had been observed and analyzed. It aims to provide theoretical basis to M. sativa genetic improvement.
Tuhuan Li,Guiping Du,Yanxiong Lei,Siqiang Chen 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.2
An open-end winding permanent magnet synchronous motor (OEW-PMSM) fed by dual inverters has good application value in the drive system of electric vehicles due to the motor’s advantages, such as high output power, wide speed range and excellent fault-tolerant ability. However, the symmetry of dual-inverter topology causes difficulty in identifying the specific faulty switch when an open-circuit fault occurs. Thus, this study proposes a switch open-circuit fault diagnosis strategy for OEW-PMSM based on finite-control-set model predictive control (FCS-MPC). With the known and unchanged switching state in each control period of FCS-MPC, the proposed strategy uses the predicted switching state to predict the phase voltage. According to the error of predicted voltage and measured voltage under switch failure, the faulty phase and faulty switch pair are identified. Finally, the relationship between switching states and error voltage is analyzed, and a diagnosis function is constructed to identify the specific faulty switch. The validity of the proposed diagnosis strategy is confirmed by the simulation and experimental results.
Lei, Yanxiong,Du, Guiping,Zhang, Yuhan,Li, Tuhuan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.6
Considering the spread spectrum problem of finite-control-set model predictive control (FCS-MPC), a fixed switching frequency strategy based on cost function reconstruction is proposed in this paper. It achieves a fixed switching frequency by selecting the optimal voltage vector through the redefined cost function. A frequency coefficient is added to this to change the selecting area of the optimal voltage vector. The proposed strategy reshapes the spectrum of the inductor current and focuses the harmonics near the switching frequency so that the design of the output LC filter is easier. Without adding any modulators or greatly increasing the number of computations, the proposed strategy reserves the excellent dynamic performance of the FCS-MPC and is convenient in terms of implementation. Finally, a 1 kW single-phase inverter is built and experiments are conducted. Experimental results demonstrate that the proposed control strategy realizes a fixed switching frequency. In addition, it has a comparative dynamic response speed and number of calculations when compared to dead-beat-based FCS-MPC. These features are beneficial to its application.
Hao Zheng,Guiping Du,Yanxiong Lei,Ruijing Wang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.6
The steady and transient performance of a bidirectional DC–DC converter (BDC) is the key to regulating bus voltage and maintaining power balance in a hybrid energy storage system. In this study, the state of charge of the energy storage element (ESE) is used to calculate the converter current control coefficient (CCCC) via Hermite interpolation. Moreover, the charging and discharging currents of the BDC are controlled by the CCCC. Thus, the ESE runs in the best working region. The linear active disturbance rejection control is used in the current inner loop of BDC to solve the problems of slow dynamic response and parameter tuning in traditional PI control. The method can deal with the great transient response and a vast range of uncertainties, improve the BDC response speed by more than 20%, compensate for the unbalanced power timely, reduce the bus voltage fluctuation, and enhance the disturbance immunity of the system. The proposed method is verified by simulations and experiments.
Position-independent wireless power transfer system delivering constant power
Zeng, Wei,Du, Guiping,Zhou, Runtang,Yang, Zijiang The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.10
A single-stage wireless power transfer (WPT) system based on the switching control capacitor (SCC) is proposed in this paper. Using the SCC instead of an ordinary capacitor gives the WPT system, an additional control degree of freedom. The proposed robust WPT system has a constant power (CP) output characteristic under a wide range of load resistance and coupling coefficient variations by adjusting the conduction angle of the SCC. When compared with constant current (CC) charging, CP charging can shorten the charging time and promote battery cycle life. Moreover, a primary side control method is proposed. It only needs to sample the primary current to identify the reflected impedance, which avoids wireless communication. When combined with the control strategy, the condition of zero-voltage switching (ZVS) is derived. Finally, a 125-W experimental prototype is built to verify the performance of the proposed method. Experimental results demonstrate that stable CP charging can be maintained during coil movement and load changes. In addition, soft switching is implemented in all situations.
Predictive charge control for LLC resonant converters
Siqiang Chen,Guiping Du,Yanxiong Lei,Tuhuan Li 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.5
A predictive charge control method based on an LLC resonant converter is proposed in this paper. The input charge in each cycle is reflected in the change of the resonant capacitor voltage. The threshold is set to compare it with the resonant capacitor voltage to control the input charge. Based on an LLC discrete predictive model, the predictive charge control predicts the threshold of the resonant capacitor voltage to regulate the output voltage. When compared with existing control methods, the predictive charge control has the advantages of an intuitive concept, a strong robustness, a simple implementation, and a simple model. It has excellent dynamic performance under various working conditions. The resonant tank can enter the steady state within one cycle without affecting the steady-state performance of the system. Through a mode analysis, this paper analyzes the proposed predictive charge control in detail. A 500 W LLC resonant converter prototype is built to verify the proposed method. Results show that both the output voltage and the resonant tank return to the steady state without fluctuations in one cycle during the processes of input voltage change and load switching.