Research on Practical Control Circuit of SVG in Single-Phase Low Voltage Field

2013 ◽  
Vol 694-697 ◽  
pp. 1469-1472
Author(s):  
Cong Mei Zha ◽  
Yan Dong
Keyword(s):  
Circuit Design ◽  
Control Strategy ◽  
Single Phase ◽  
Reactive Power ◽  
Control Method ◽  
Low Voltage ◽  
Current Control ◽  
Control Circuit ◽  
Voltage Source ◽  
Static Var Generator

For the use of Static Var Generator (SVG) in dynamic reactive power compensation of low voltage field, this paper proposes a reactive current control strategy suitable for single-phase bridge voltage source SVG and gives the main control circuit of this control method. The experimental results verify the effectiveness and practicality of this control strategy and the circuit design.

scholarly journals Fault Ride through Capability Augmentation of a DFIG-Based Wind Integrated VSC-HVDC System with Non-Superconducting Fault Current Limiter

2019 ◽  
Vol 11 (5) ◽  
pp. 1232 ◽  
Author(s):  
Md Alam ◽  
Mohammad Abido ◽  
Alaa Hussein ◽  
Ibrahim El-Amin
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Current Control ◽  
Control Mode ◽  
Voltage Source ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Hvdc System ◽  
Fault Ride Through ◽  
Current Limiter

This paper proposes a non-superconducting bridge-type fault current limiter (BFCL) as a potential solution to the fault problems of doubly fed induction generator (DFIG) integrated voltage source converter high-voltage DC (VSC-HVDC) transmission systems. As the VSC-HVDC and DFIG systems are vulnerable to AC/DC faults, a BFCL controller is developed to insert sizeable impedance during the inception of system disturbances. In the proposed control scheme, constant capacitor voltage is maintained by the stator VSC (SVSC) controller, while current extraction or injection is achieved by rotor VSC (RVSC) controller. Current control mode-based active and reactive power controllers for an HVDC system are developed. Balanced and different unbalanced faults are applied in the system to show the effectiveness of the proposed BFCL solution. A DFIG wind-based VSC-HVDC system, BFCL, and their controllers are implemented in a real time digital simulator (RTDS). The performance of the proposed BFCL control strategy in DFIG-based VSC-HVDC system is compared with a series dynamic braking resistor (SDBR). Comparative RTDS implementation results show that the proposed BFCL control strategy is very efficient in improving system fault ride through (FRT) capability and outperforms SDBR in all cases considered.

scholarly journals Hybrid Control Strategy of MPC and DBC to Achieve a Fixed Frequency and Superior Robustness

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1176 ◽  
Author(s):  
Yuhan Zhang ◽  
Guiping Du ◽  
Jiajian Li ◽  
Yanxiong Lei
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Control Method ◽  
Hybrid Control ◽  
Voltage Source ◽  
Switching Frequency ◽  
Transient Time ◽  
Finite Control ◽  
Control Set ◽  
Comparative Results

In this paper, a hybrid control strategy for power converters, based on improved deadbeat control (DBC) and improved finite control set model predictive control (MPC), is proposed. The presented control strategy employs a switched method to achieve a fixed switching frequency while maintaining a fast transient time. Moreover, the proposal incorporates error correction to achieve superior robustness. A prototype of a single-phase voltage source rectifier is established to verify the performance of the proposal. The comparative results with conventional MPC are given and illustrate the merits of the proposed control method.

scholarly journals Scalable Single-Phase Multi-Functional Inverter for Integration of Rooftop Solar-PV to Low-Voltage Ideal and Weak Utility Grid

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 302 ◽  
Author(s):  
Venkata Subrahmanya Raghavendra Varaprasad Oruganti ◽  
Venkata Sesha Samba Siva Sarma Dhanikonda ◽  
Marcelo Godoy Simões
Keyword(s):  
Distribution System ◽  
Single Phase ◽  
Reactive Power ◽  
Low Voltage ◽  
Current Control ◽  
Solar Irradiation ◽  
Switching Frequency ◽  
Solar Pv ◽  
Distorted Grid ◽  
Rooftop Solar

Integration of rooftop solar-PV (RTSPV) systems and extensive use of nonlinear loads in the low-voltage distribution system (LVDS) leads to poor power quality (PQ). Therefore, it is necessary to address the issues leading to poor PQ at the point of common coupling of the LVDS. In this article, a multi-band hysteresis current control (MB-HCC) for the multi-functional inverter (MFI) is proposed which improves the efficiency of the MFI and also enhances the PQ of the LVDS. The MB-HCC uses simple switching logic and outperforms in its multi-functional tasks such as active power injection and power conditioning. MB-HCC offers better efficiency over variable double-band HCC (VDB-HCC) as it operates at a lower switching frequency. The performance of the proposed system is simulated by using MATLAB/Simulink and validated by OPAL-RT based real-time simulation studies. During the variation of solar irradiation, the proposed MFI has an average efficiency of 98.5% under the ideal grid and 97.34% under the distorted grid. Moreover, the percentage of Total Harmonic Distortion under ideal and distorted grid conditions is brought down to below 5%, and also, reactive power compensation maintains unity power factor operation complying with the IEEE-519-2014 and 1547 standards. These results substantiate the hypothesis of scalability of the single-phase MB-HCC-based MFI for an LVDS contributing to economy and ecology.

scholarly journals Improved Operation Strategy with Alternative Control Targets for Voltage Source Converter under Harmonically Distorted Grid Considering Inter-Harmonics

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1236 ◽  
Author(s):  
Bo Pang ◽  
Heng Nian
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Control Object ◽  
Current Control ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Pass Filter ◽  
Control Gain ◽  
Distorted Grid ◽  
The Stability

This paper proposed an improved control method for grid-connected voltage source converter (VSC), when the grid voltage consisted of the integer harmonics and inter-harmonics. Control object of the proposed control can be alternated to achieve the sinusoidal current or smooth output power, which enhances the operation adaption of VSC under the harmonically distorted grid. On the basis of a PI regulator in the fundamental current control loop, the novel control strategy was proposed with a supplementary controller which consisted of a prepositive high-pass filter and a modified proportional-derivative controller. In the proposed control, the inter-harmonics could be suppressed without detecting frequency, while the traditional resonator was effective in the premise of knowing the harmonics frequency. Also, the influence of control gain on the steady performance and the stability of VSC was analyzed, and the influences on the fundamental control caused by the proposed controller were also analyzed to verify the practicability of the proposed control strategy. Finally, the effectiveness of the proposed strategy was verified by the experiments.

scholarly journals MMC-Based PV Single-Phase System with Distributed MPPT

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3964 ◽  
Author(s):  
Simone Barcellona ◽  
Marzio Barresi ◽  
Luigi Piegari
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Daily Basis ◽  
Maximum Power ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Phase System ◽  
Partial Shading

The presence and evolution of static power converters in electric grids are growing on a daily basis. Starting from the most used voltage source converter (VSC), passing through the use of multilevel converters, the most recent configuration is the so-called modular multilevel converter (MMC). Because of its intrinsic advantages, it is used not only in high-voltage systems but also in low- and medium-voltage ones to interface renewable energy sources such as photovoltaic (PV) panels. Several configurations and maximum power point tracker (MPPT) algorithms have been proposed and analyzed for MMC-PV-based systems. However, when using distributed MPPTs, partial shading conditions cause a problem. The PV panel can be directly connected to the MMC using its dc link or submodule. Based on this configuration, this paper proposes a novel control strategy that tracks both the ac grid current and ac circulating current for a single-phase low-voltage system to obtain the maximum power under any irradiance condition. The effectiveness of the proposed control strategy is demonstrated through time-domain simulation results.

Dual current control strategy to fulfill LVRT requirements in WECS

2014 ◽  
Vol 33 (5) ◽  
pp. 1665-1677 ◽  
Author(s):  
Matías Díaz ◽  
Roberto Cárdenas-Dobson
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Current Control ◽  
Power Delivery ◽  
Positive Sequence ◽  
Content Type ◽  
Grid Voltage ◽  
Signal Cancellation ◽  
Laboratory Prototype

Purpose – The purpose of this paper is to investigate a control strategy to fulfill low-voltage ride through (LVRT) requirements in wind energy conversion system (WECS). Design/methodology/approach – This paper considers an active front-end converter of a grid connected WECS working under grid fault conditions. Two strategies based on symmetrical components are studied and proposed: the first one considers control only for positive sequence control (PSC); the second one considered a dual controller for positive and negative sequence controller (PNSC). The performance of each strategy is studied on LVRT requirements fulfillment. Findings – This paper shows presents a control strategy based on symmetrical component to keep the operation of grid-connected WECS under unsymmetrical grid fault conditions. Research limitations/implications – This work is being applied to a 2 kVA laboratory prototype. The lab prototype emulates a grid connected WECS. Originality/value – This paper validate the PNSC strategy to LVRT requirements fulfillment by experimental results obtained for a 2 kVA laboratory prototype. PNSC strategy allows constant active power delivery through grid-voltage dips. In addition, the proposed strategy is able to grid-voltage support by injection of reactive power. Additional features are incorporated to PNSC: sequence separation method using delay signal cancellation and grid frequency identification using phase locked loop.

scholarly journals Topology and Control Strategy of PV MVDC Grid-Connected Converter with LVRT Capability

2021 ◽  
Vol 11 (6) ◽  
pp. 2739
Author(s):  
Huan Wang ◽  
Yu Zhou ◽  
Xinke Huang ◽  
Yibo Wang ◽  
Honghua Xu
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Low Voltage ◽  
Current Control ◽  
Medium Voltage ◽  
Low Voltage Ride Through ◽  
Feedback Capacitor ◽  
Lc Filter ◽  
And Control ◽  
Medium Voltage Dc

This paper proposes an isolated buck-boost topology and control strategy for the photovoltaic (PV) medium-voltage DC (MVDC) converter with low-voltage ride through (LVRT) capability. The proposed isolated buck-boost topology operates on either boost or buck mode by only controlling the active semiconductors on the low-voltage side. Based on this topology, medium-voltage (MV) dc–dc module is able to be developed to reduce the number of modules and increase the power density in the converter, which corresponds to the first contribution. As another contribution, a LVRT method based on an LC filter for MVDC converter is proposed without additional circuit and a feedback capacitor current control method for the isolated buck-boost converter is proposed to solve the instability problem caused by the resonance spike of the LC filter. Five kV/50 kW SiC-based dc–dc modules and ±10 kV/200 kW PV MVDC converters were developed. Experiments of the converter for MVDC system in the normal and LVRT conditions are presented. The experimental results verify the effectiveness of the proposed topology and control strategy.

Single-Phase Independent Droop Control Strategy in Low-Voltage Microgrid

2015 ◽  
Vol 733 ◽  
pp. 684-690 ◽  
Author(s):  
Zhong Lin Zhang ◽  
Tao Wang
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Control Method ◽  
Low Voltage ◽  
Frequency Stability ◽  
Droop Control ◽  
Level Control ◽  
Independent Control ◽  
Three Phase ◽  
Micro Grid

In the three-phase four-wire low-voltage micro grid, three-phase imbalance usually happens because of a large number of single-phase loads. In this situation, the traditional control method cannot effectively control the voltage and frequency stability when the low-voltage micro grid operates in the island mode. According to the characteristics of the three-phase four-wire low-voltage micro grid, this paper designs a single-phase independent control based on the droop control. This paper firstly uses the improved droop control considering that the impedance characteristic of the low voltage micro gird is mainly resistance, and also designs single-phase independent control to ensure the control system have the ability to run under the unbalanced loads. Then this paper designs a two-level control strategy to control the voltage and frequency in the micro grid during the island operation. Finally, a simulation analysis based on the proposed method is used to prove the effectiveness. A micro grid is set up on PSCAD, and verifies the effectiveness of the single-phase control strategy based on the improved droop control. The proposed method can also realize the requirement of the voltage and frequency stability during the island operation. At the same time, the control method proposed in this paper can achieve the control objective under the condition of unbalanced three-phase.

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