A hybrid control method for three-phase grid-connected inverters with high quality power

2009 ◽  
Author(s):  
Zitao Wang ◽  
Liuchen Chang
Keyword(s):  
Control Method ◽  
Hybrid Control ◽  
High Quality ◽  
Three Phase

A hybrid controller for PWM active rectifiers based LCL filters

2015 ◽  
Vol 34 (4) ◽  
pp. 1229-1251 ◽  
Author(s):  
Amira Marzouki ◽  
Mahmoud Hamouda ◽  
Farhat Fnaiech
Keyword(s):  
Control Method ◽  
Hybrid Control ◽  
High Quality ◽  
Lcl Filter ◽  
Content Type ◽  
Linear Controller ◽  
Dc Bus ◽  
Bus Voltage ◽  
Active Rectifiers

Purpose – The purpose of this paper is to propose a new hybrid control method of pulse width modulation (PWM) active rectifiers tied to the grid through an LCL filter. The control method is designed with the aim to achieve a perfect regulation of the dc-bus voltage; a near unity input power factor (UIPF) operation as well as a high quality of the line currents. Design/methodology/approach – The proposed hybrid control method consists of a PI-based linear controller cascaded with a nonlinear one. The nonlinear controller (inner loop) is designed using the input-output feedback linearization (IOFL) theory. It should control both the dc-bus voltage and the input currents at the converter’s poles. The linear controller (outer loop) is devoted to control the reactive line current so as to achieve a near UIPF. Findings – A perfect regulation of the dc-bus voltage and a near UIPF operation are achieved. Moreover, a high quality of the line currents is obtained. The robustness and effectiveness of the proposed control method have been successfully tested under variation of the dc voltage reference as well as grid and load disturbances. Practical implications – The proposed method is useful for single-stage and two-stage grid connected photovoltaic systems, wind energy conversion, and distributed power generation systems. Originality/value – The main novelty of this paper is the combination of linear and nonlinear controllers with the aim to control a PWM active rectifier tied to the grid through a third-order LCL filter. In the opinion, such control method has not been applied to this converter in earlier research papers. The numerical simulations carried out under normal and abnormal conditions confirm the effectiveness of the proposed approach.

scholarly journals Hybrid Control for Bidirectional Z-Source Inverter for Locomotives

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Vasanthi Vijayan ◽  
S. Ashok
Keyword(s):  
Control Method ◽  
Hybrid Control ◽  
Modulation Index ◽  
Voltage Source ◽  
Small Scale ◽  
Voltage Source Inverters ◽  
Variable Voltage ◽  
Three Phase ◽  
Voltage Stress ◽  
Electric Traction

Electric traction uses three phase locomotives in main line services. Three phase locomotives consist of voltage source inverters for driving the traction motors. This paper proposes a hybrid algorithm for bidirectional Z-source inverters in accelerating region of operation of locomotives. The speed control method adopted is same as that in the existing three phase locomotives which is variable voltage variable frequency. Bidirectional Z-source inverter is designed for getting the same output power as in voltage source inverter fed locomotives. Simulation is done in all regions of traction speed curve, namely, acceleration, free running, and braking by regeneration. The voltage stress across the devices and modulation index are considered while analyzing the proposed control algorithm. It is found that the modulation index remains at a high value over the entire range of frequencies. Due to the higher value of modulation index the harmonics in the inverter output voltage is reduced. Also the voltage stress across devices is limited to a value below the device rating used in the present three phase locomotives. A small scale prototype of the bi-directional Z-source inverter fed drive is developed in the laboratory and the hybrid control was verified in the control topology.

scholarly journals D-PMU and 5G-Network-Based Coordination Control Method for Three-Phase Imbalance Mitigation Units in the LVDN

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2754
Author(s):  
Mengmeng Xiao ◽  
Shaorong Wang ◽  
Zia Ullah
Keyword(s):  
Mobile Networks ◽  
Control Method ◽  
Low Voltage ◽  
Control Unit ◽  
Distribution Networks ◽  
Optimal Operation ◽  
Positive Sequence ◽  
Measurement Unit ◽  
Control Units ◽  
Three Phase

Three-phase imbalance is a long-term issue existing in low-voltage distribution networks (LVDNs), which consequently has an inverse impact on the safe and optimal operation of LVDNs. Recently, the increasing integration of single-phase distributed generations (DGs) and flexible loads has increased the probability of imbalance occurrence in LVDNs. To overcome the above challenges, this paper proposes a novel methodology based on the concept of "Active Asymmetry Energy-Absorbing (AAEA)" utilizing loads with a back-to-back converter, denoted as “AAEA Unit” in this paper. AAEA Units are deployed and coordinated to actively absorb asymmetry power among three phases for imbalance mitigation in LVDNs based on the high-precision, high-accuracy, and real-time distribution-level phasor measurement unit (D-PMU) data acquisition system and the 5th generation mobile networks (5G) communication channels. Furthermore, the control scheme of the proposed method includes three control units. Specifically, the positive-sequence control unit is designed to maintain the voltage of the DC-capacitor of the back-to-back converter. Likewise, the negative-sequence and zero-sequence control units are expected to mitigate the imbalanced current components. A simple imbalanced LVDN is modeled and tested in Simulink/Matlab (MathWorks, US). The obtained results demonstrate the effectiveness of the proposed methodology.

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