Decoupled Alpha-Beta control for distortion reduction in three-phase low-voltage Inverters

Author(s):  
Padmavathi Lakshmanan
Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2754
Author(s):  
Mengmeng Xiao ◽  
Shaorong Wang ◽  
Zia Ullah

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.


Author(s):  
Qiang Chen ◽  
Jianping Xu ◽  
Fei Zeng ◽  
Rui Huang ◽  
Lei Wang

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2899 ◽  
Author(s):  
Alexis B. Rey-Boué ◽  
N. F. Guerrero-Rodríguez ◽  
Johannes Stöckl ◽  
Thomas I. Strasser

This article deals with the vector control in dq axes of a three-phase grid-connected photovoltaic system with single-stage topology and low-voltage-ride-through capability. The photovoltaic generator is built using an array of several series-parallel Suntech PV modules and is modeled as a Lookup Table (two-dimensional; 2-D). The requirements adopted when grid voltage sags occur are based in both the IEC 61400-21 European normative and the allowed amount of reactive power to be delivered according to the Spanish grid code, which avoids the disconnection of the inverter under grid faults by a limitation in the magnitude of the three-phase output inverter currents. For this, the calculation of the positive- and negative-sequences of the grid voltages is made and a conventional three-phase Phase-Locked Loop is used for the inverter-grid synchronization, allowing the control of the active and reactive powers solely with the dq components of the inverter currents. A detailed enhanced flowchart of the control algorithm with low-voltage-ride-through capability is presented and several simulations and experiments using Matlab/SIMULINK and the Controller Hardware-in-the-Loop simulation technique, respectively, are run for several types of one- and three-phase voltage sags in order to validate its behavior.


Author(s):  
Achmad Solih ◽  
Jamaaluddin Jamaaluddin

Panel system power distribution at Lippo Plaza Mall Sidoarjo consists of several parts, namely from Cubicle 20 KV, 20 KV step-down transformer for 380 V, then the supply to LVMDP (Low Voltage Main Distribution Panel) The new panel to the user. Before delivery to users to note that the power factor is corrected using a capacitor bank. Less good a power factor is turned into inductive load on the capacitor bank so that temperatures high  because of high load resulting capacitor bank erupt. To overcome in this study proposes a safety panel automation power distribution control system using a microcontroller. Control system microcontrollers for safety panel power distribution consists of: Microcontroller (Arduino Nano), Light sensor (LDR), temperature sensor (LM35DZ), LCD 16x2 I2C, Actuators (fan, buzzer, relay switch breaker network three phase), switch ( relay 5 VDC), ADC as Input data. The working principle of this microcontroller LM35DZ if the sensor detects a high temperature fan will flash, if the LDR sensor detects sparks then the buzzer will sound as a warning sign of the dangers and disconnected the electricity network. From the design of a safety tool for power distribution panels due to high temperatures or sparks as well as the expected rate of fire outbreaks can be prevented.


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