scholarly journals An Input-Parallel-Output-Series Switched-Capacitor Three-level Boost Converter with a Three-Loop Control Strategy

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2631
Author(s):  
Jianfei Chen ◽  
Caisheng Wang ◽  
Jian Li
Keyword(s):  
Control Strategy ◽  
Current Loop ◽  
Loop Control ◽  
Dc Microgrids ◽  
Solar Power Generation ◽  
Capacitor Voltage ◽  
Industry Applications ◽  
Voltage Balance ◽  
Simulation And Experiment ◽  
Parallel Output

There has been increasing interest for industry applications, such as solar power generation, fuel cell systems, and dc microgrids, in step-up dc-dc converters with reduced number of components, low component stress, small input ripples and high step-up ratios. In this paper, an input-parallel-output-series three-level boost (IPOS-SC-TLB) converter is proposed. In addition to achieving the required performance, the input and output terminals can share the same ground and an automatic current balance function is also achieved in the IPOS-SC-TLB converter. Besides, a capacitor voltage imbalance mechanism was revealed and a three-loop control strategy composed of output voltage loop, input current loop and voltage-balance loop was proposed to address the voltage imbalance issue. Finally both simulation and experiment studies have been conducted to verify the effectiveness of the IPOS-SC-TLB converter and the three-loop control strategy.

scholarly journals The Fuzzy PI Controller for PMSM’s Speed to Track the Standard Model

2020 ◽  
Vol 2020 ◽  
pp. 1-20 ◽  
Author(s):  
Nguyen Vu Quynh
Keyword(s):  
Standard Model ◽  
Integrated Circuit ◽  
High Speed ◽  
Permanent Magnet Synchronous Motor ◽  
Viscous Friction ◽  
Pi Controller ◽  
Current Loop ◽  
Loop Control ◽  
Simulation And Experiment ◽  
Fuzzy Pi Controller

This paper proposes a fuzzy PI controller to control the speed of a permanent magnet synchronous motor (PMSM). The structure of the system includes the speed loop controller (SLC) and the current loop controller (CLC). The speed loop controller is the fuzzy PI and standard model (SM). The CLC includes vector control and the space vector pulse width modulation (SVPWM). It compiles two closed-loop control systems for the PMSM. This research uses a very high-speed integrated circuit hardware description language (VHDL) to implement the proposed algorithm and embed it into Matlab/Simulink for simulation. Based on the PMSM parameter, this article tests the controller’s correctness with some of the load cases by changing the combined inertia and viscous friction of rotor and load. After success in simulation, the system is tested again by experiment on the FPGA kit. The simulation and experiment results show that when the load changes, the PMSM speed is still stable. The novelty of this research is that it compares two kinds of controllers between simulation and experiment results.

scholarly journals Feedback Linearization and Sliding Mode Control for VIENNA Rectifier Based on Differential Geometry Theory

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Xiang Lu ◽  
Yunxiang Xie ◽  
Li Chen
Keyword(s):  
Differential Geometry ◽  
Sliding Mode Control ◽  
Control Strategy ◽  
Feedback Linearization ◽  
Sliding Mode ◽  
Current Loop ◽  
Loop Control ◽  
Mode Control ◽  
Vienna Rectifier ◽  
Feedback Linearization Control

Aiming at the nonlinear characteristics of VIENNA rectifier and using differential geometry theory, a dual closed-loop control strategy is proposed, that is, outer voltage loop using sliding mode control strategy and inner current loop using feedback linearization control strategy. On the basis of establishing the nonlinear mathematical model of VIENNA rectifier ind-qsynchronous rotating coordinate system, an affine nonlinear model of VIENNA rectifier is established. The theory of feedback linearization is utilized to linearize the inner current loop so as to realize thed-qaxis variable decoupling. The control law of outer voltage loop is deduced by utilizing sliding mode control and index reaching law. In order to verify the feasibility of the proposed control strategy, simulation model is built in simulation platform of Matlab/Simulink. Simulation results verify the validity of the proposed control strategy, and the controller has a strong robustness in the case of parameter variations or load disturbances.

The Control Strategy and Simulation of Three-Phase Grid-Connected Photovoltaic System

2012 ◽  
Vol 608-609 ◽  
pp. 164-168
Author(s):  
Jian Jun Su ◽  
Men Yue Hu ◽  
Hong Yan Gong ◽  
Hai Tao Sun ◽  
Zhi Jian Hu ◽  
...  
Keyword(s):  
Control Strategy ◽  
Photovoltaic System ◽  
Current Loop ◽  
Maximum Power Point ◽  
Loop Control ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Three Phase ◽  
Power Point ◽  
Research Situation

Firstly the research situation for grid-connected photovoltaic (PV) is introduced, then, the engineering mathematical model of PV cells is introduced. The perturbation and observation algorithm is chosen as the maximum power point tracking (MPPT) algorithm. The SPWM double-loop control strategy with outer voltage loop and inner current loop is described and a three-phase grid-connected photovoltaic model is established. The simulation results demonstrate the validity and correctness of the simulation model built in this paper.

scholarly journals Enhanced Boost Factor for Three-Level Quasi-Switched Boost T-Type Inverter

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3920
Author(s):  
Duc-Tri Do ◽  
Vinh-Thanh Tran ◽  
Minh-Khai Nguyen
Keyword(s):  
Power Devices ◽  
Voltage Unbalance ◽  
Conduction Loss ◽  
Capacitor Voltage ◽  
Voltage Balance ◽  
Boost Factor ◽  
Simulation And Experiment ◽  
Capacitor Voltage Balance ◽  
Laboratory Prototype ◽  
Component Rating

A new modulation strategy has been introduced in this paper in order to enhance the boost factor for the three-level quasi-switched boost T-type inverter (3L-qSBT2I). Under this approach, the component rating of power devices is significantly decreased. Moreover, the use of a larger boost factor produces a smaller shoot-through current. This benefit leads to reducing the conduction loss significantly. Furthermore, the neutral voltage unbalance is also considered. The duty cycle of two active switches of a quasi-switched boost (qSB) network is redetermined based on actual capacitor voltages to recovery balance condition. Noted that the boost factor will not be affected by the proposed capacitor voltage balance strategy. The proposed method is taken into account to be compared with other previous studies. The operation principle and overall control strategy for this configuration are also detailed. The simulation and experiment are implemented with the help of PSIM software and laboratory prototype to demonstrate the accuracy of this strategy.

Research on Single-Phase Inverter Dual Loop Control Technology with Feed-Forward Compensation

2014 ◽  
Vol 960-961 ◽  
pp. 1285-1289
Author(s):  
Shu Jun Yao ◽  
Jun Luo ◽  
Min Xiao Han ◽  
Yang Cheng Xiang Song
Keyword(s):  
Control Strategy ◽  
Current Loop ◽  
Nonlinear Load ◽  
New Approach ◽  
Feed Forward ◽  
Loop Control ◽  
Assignment Method ◽  
Control Scheme ◽  
Waveform Distortion ◽  
Single Phase Inverter

A new approach of dual closed-loop control strategy is proposed, and the internal cause of the inverter output voltage waveform distortion is analyzed in this paper. The ability to resist load disturbance is improved by load current feed-forward compensation in the approached scheme. With inner current loop improving the speed of dynamic response, nonlinear load adaptability is enhanced. Pole assignment method is used to design controller parameters, the control scheme is simulated in PSCAD/EMTDC, the nice performance of the proposed control strategy is verified by the simulation results.

scholarly journals Virtual Synchronous Generator Control of VSC-HVDC System Based on MMC of Hybrid Topology

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jie Wu ◽  
Chuanjiang Li
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Structural Characteristics ◽  
Synchronous Generator ◽  
Current Control ◽  
Current Loop ◽  
Power Module ◽  
Loop Control ◽  
Hybrid Topology ◽  
Virtual Synchronous Generator

For a VSC-HVDC transmission system based on a hybrid topology converter of full-bridge and half-bridge, a kind of virtual synchronous generator (VSG) control strategy which can be applied to modular multilevel converter (MMC) grid-connected structure was researched and proposed. First, based on the conventional VSG control strategy, the energy stored in the equivalent capacitor of MMC power module was used to imitate the rotor inertia of synchronous generator. The characteristics of generator can be simulated during transient frequency fluctuations and it can help relieve the power fluctuations. Secondly, with respect to the structural characteristics of the direct grid connection through the reactor on the AC side of the MMC, which is unlike the microgrid inverter, there are no additional filter capacitors. So, the existing commonly used VSG control strategy of the microgrid inverter and double-closed-loop structure composed of filter capacitor voltage and AC current cannot be directly applied. For this, a method where the given values of inner current loop are calculated by grid impedance matrix was used. So, a double-closed-loop control structure composed of a power outer loop based on VSG control and a current inner loop is obtained. It can effectively improve the current control capability during the transient process. Finally, a hybrid MMC simulation model was built based on PSCAD to verify the correctness and effectiveness of the proposed methods.

scholarly journals A Novel Control Strategy for DC-Link Voltage Balance and Reactive Power Equilibrium of a Single-Phase Cascaded H-Bridge Rectifier

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 51 ◽  
Author(s):  
Chengwei Luo ◽  
Derong Luo ◽  
Shoudao Huang ◽  
Gongping Wu ◽  
Hongzhang Zhu ◽  
...  
Keyword(s):  
Working Conditions ◽  
Duty Cycle ◽  
Control Strategy ◽  
Reactive Power ◽  
Coupling Effect ◽  
Active Duty ◽  
Integral Control ◽  
Loop Control ◽  
Voltage Balance ◽  
Bridge Rectifier

The dc-link voltage balance and reactive power equilibrium of the cascaded H-bridge rectifier (CHBR) are the prerequisites for the safe and stable operation of the system. However, the conventional PI (Proportional-Integral) control strategy only puts emphasis on the CHBR dc-link voltage balance without taking into account its reactive power equilibrium under capacitive and inductive working conditions. For this reason, this paper has proposed a novel control strategy for the CHBR that can not only balance dc-link voltage, but also achieve reactive power equilibrium and eliminate the coupling effect between the voltage-balancing controller (VBC) and original system controller (OSC). The control strategy can achieve dc-link voltage balance and the reactive power equilibrium of the CHBR through modifying the active duty cycle by closed loop control, and adjusting the reactive duty cycle relatively according to the modifiable amount of the active duty cycle. Moreover, the strategy can eliminate the coupling effect between the VBC and OSC by the open loop control modification of the active and reactive duty cycle of any H-bridge module in CHBR. Simulations and experiments have shown that the proposed control strategy is feasible and effective in performing the CHBR dc-link voltage balance and reactive power equilibrium under all working conditions and load variations.

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