scholarly journals Control-Loop-Based Impedance Enhancement of Grid-Tied Inverters for Harmonic Suppression: Principle and Implementation

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2874
Author(s):  
Fei Wang ◽  
Lijun Zhang ◽  
Hui Guo ◽  
Xiayun Feng
Keyword(s):  
Control Method ◽  
Impedance Control ◽  
Current Loop ◽  
Harmonic Suppression ◽  
Control Loop ◽  
Output Impedance ◽  
Loop Control ◽  
Control Loops ◽  
Capacitor Voltage

To understand different control loops that have been proposed to improve the quality of current into grid from the perspective of output impedance, control-loop-based output impedance enhancement of grid-tied inverters for harmonic suppression is proposed in this paper. The principle and generalized control loop deduction are presented for reshaping the output impedance. Taking a traditional LCL (Inductor-Capacitor-Inductor)-type inverter with dual-loop control as an example, different kinds of control loop topologies are derived step by step and further optimized for the implementation of the proposed principle. Consequently, the improved control consists of a filtering-capacitor voltage loop, and a grid current loop is found which can remove the existing inner capacitor current loop and therefore simplify the control. Finally, the effectiveness of the proposed control method is compared with the existing method and both are verified by simulations and experiments.

Research on Controlling Method of High-Power Electromagnetic Transmitter Power Supply

2013 ◽  
Vol 339 ◽  
pp. 614-620
Author(s):  
Fei Yu
Keyword(s):  
High Power ◽  
Power Supply ◽  
Control Method ◽  
Current Loop ◽  
Complex Environments ◽  
Loop Control ◽  
Transmitter Power ◽  
Current Sharing ◽  
Current Sharing Control ◽  
Electromagnetic Transmitter

High-power electromagnetic transmitter power supply is an important part of deep geophysical exploration equipment, especially in complex environments, where how to control the high accuracy and stable output of the power supply as well as the redundancy safety of the system become the key issue in its designing. A triple-loop control including inner current loop, outer voltage loop and load current forward feedback and a digitalized voltage/current sharing control method are proposed for the realization of the rapid, stable and highly accurate output of the system. System simulation and field geological exploration experiments demonstrate the effectiveness of the control method which could ensure both the systems excellent stability and the outputs accuracy.

Research on the Hydraulic Actuator Control of the Quadruped Robot Based Dual-Loop

2012 ◽  
Vol 569 ◽  
pp. 533-538
Author(s):  
En Chao Yang ◽  
Qing Wei ◽  
Run Bin Cai ◽  
Hong Xu Ma
Keyword(s):  
Position Control ◽  
Control Method ◽  
Quadruped Robot ◽  
Order System ◽  
Control Loop ◽  
Hydraulic Actuator ◽  
Loop Control ◽  
Actual Force ◽  
Target Force ◽  
Actuator Control

This paper presents modeling and dual-loop control of a non-linear hydraulic actuator applied on the quadruped robot. The pure position control of the actuator is hard to achieve because it’s a three-order system. So we propose the dual-loop control method to decompose it. The controller structure of the system is composed of two loops namely outer position control loop and inner force control loop. Outer loop controller is used to calculate the optimum target force to reject the errors of the position control, while, the inner loop controller is used to keep the actual force close to this desired force.

scholarly journals The new power sharing method for threephase parallel inverters with nonlinear loads

2015 ◽  
Vol 18 (1) ◽  
pp. 16-28
Author(s):  
Phuong Minh Le ◽  
Dai Tan Le ◽  
Hoa Thi Xuan Pham
Keyword(s):  
Reactive Power ◽  
Energy System ◽  
Active Power ◽  
Power Sharing ◽  
Control Loop ◽  
Output Impedance ◽  
Nonlinear Loads ◽  
Control Scheme ◽  
Virtual Impedance

This paper presents a new method for controling parallel inverters to share active power and reactive power in the energy system with non-linear loads. In these systems, the virtual output impedance is usually added to the control loop of each inverter to improve the active power and reactive power sharing as well as the quality of the voltage system. Paper also proposes a kind of virtual impedance as a second-order general-integrator (SOGI) scheme. The simulation results in Matlab Simulink show the ability of the proposed controller to good share power P-Q, when connected with unbalanced and nonlinear loads. By using the proposed algorithm allows to reduce the voltage THD to 1.9% and 1.2% for unbalanced and nonlinear loads according by comparision with traditional control scheme.

scholarly journals Decentralized Control Method of ISOP Converter for Input Voltage Sharing and Output Current Sharing in Current Control Loop

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1114
Author(s):  
Sung-Hun Kim ◽  
Bum-Jun Kim ◽  
Jung-Min Park ◽  
Chung-Yuen Won
Keyword(s):  
Decentralized Control ◽  
Control Method ◽  
Input Voltage ◽  
Current Control ◽  
Control Loop ◽  
Output Current ◽  
Signal Model ◽  
Control Loops ◽  
Current Sharing ◽  
Small Signal Model

Input-Series-Output-Parallel (ISOP) converters, a kind of modular converter, are used in high-input voltage and high-output current applications. In ISOP converters, Input Voltage Sharing (IVS) and Output Current Sharing (OCS) should be implemented for stable operation. In order to solve this problem, this paper proposes a decentralized control method. In the proposed control, output current reference is changed according to the decentralized control characteristic in individual current control loops. In this way, the proposed control method is able to implement IVS and OCS without communication. Also, this method can be easily used in current control loops and has high reliability compared to conventional control methods that require communication. In this paper, the operation principle is described to elucidate the proposed control and a small signal model of an ISOP converter is also implemented. Based on the small signal model, IVS stability analysis is performed using pole-zero maps with varying coefficients and control gains. In addition, the current control loop is designed in a stable region. In order to demonstrate the proposed control method, a prototype ISOP converter is configured using full-bridge converters. The performance of IVS and OCS in an ISOP converter is verified by experimental result.

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.

Research on TZSI Control Method

2013 ◽  
Vol 773 ◽  
pp. 51-57
Author(s):  
Lei Pan ◽  
He Xu Sun ◽  
Lan Fang Fu ◽  
Bin Liu ◽  
Ran Gao ◽  
...  
Keyword(s):  
Control Method ◽  
Current Loop ◽  
Small Signal ◽  
Signal Model ◽  
Loop Control ◽  
Modeling And Analysis ◽  
Voltage Stress ◽  
Network Output ◽  
Small Signal Modeling ◽  
Conduction Mode

In transformer-Z-source inverters (TZSI), the impedance networks consist of a transformer and one capacitor. While maintaining the main features of traditional Z-source network, the new networks exhibit some unique advantages, such as the increased voltage gain and reduced voltage stress in the voltage-fed TZSI, when the turns ratio of the transformer windings is over 1. This paper contributes to the ac small signal modeling and analysis of TZSI in continuous conduction mode. The ac small signal model considers the dynamics introduced by network uniquely contained in TZSI. And a double loop control method which is impedance source network output dc voltage and current loop has been proposed to realize the control of TZSI. Results of simulations and experiments are used to validate the control method and show that this method is correct and feasible.

Control of CSR PWM Outer Current Loop Based on Fuzzy Algorithm

2014 ◽  
Vol 672-674 ◽  
pp. 972-976 ◽  
Author(s):  
Zhuo Wang ◽  
Zhang Qing
Keyword(s):  
Fuzzy Controller ◽  
Fuzzy Variable ◽  
Current Control ◽  
Rate Of Change ◽  
Current Loop ◽  
Control Performance ◽  
Control Loop ◽  
Fuzzy Algorithm ◽  
Loop Control ◽  
Control Configuration

This paper expounds the double closed-loop control configuration which is composed by the AC inner current control loop and the DC outer current loop of the CSR PWM rectifier ,and the functions of the inner current loop and the outer current control loop are pointed out. To improve the control performance ,a current controller whose DC outer current loop is designed by the fuzzy algorithm is used. The DC outer current loop error fuzzy variable E’s membership functions is researched ,and also the Rate of change of the current error fuzzy variable EC and the fuzzy variable Δi which is exported by fuzzy controller. Their influences to the control performance are considered. After the simulation experiments, it shows that the DC outer current loop fuzzy control is feasible and effective. The performance of the outer current control loop can be improved.

scholarly journals The MRAC based-adaptive control system for controlling the speed of direct current motor

2020 ◽  
Vol 19 (2) ◽  
pp. 723
Author(s):  
Manh-Cuong Nguyen ◽  
Duc-Phuc Vuong ◽  
Trong-Thang Nguyen
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Direct Current ◽  
Reference Model ◽  
Control Object ◽  
Adaptive Controller ◽  
Adaptive Control System ◽  
Control Loop ◽  
Control Loops

<p><span>This research aims to propose an adaptive control system for controlling the speed of the Direct Current (DC) motor. The system consists of two control loops: the first control loop is a traditional PID controller and the second control loop is an adaptive controller. The role of the adaptive controller is adjusting the output of the control object follows with the output of the reference model. The adjustment mechanism is very simple, but the quality of the whole system is very high: the conversion time is short and there isn't overshoot. The quality of the proposed adaptive control system is also compared to the traditional PID control system to show the advantages of the new system.</span></p>

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