High-Frequency Grid Current Control of Parallel Inverters

2018 ◽  
Author(s):  
Sebastian Bruske ◽  
Sante Pugliese ◽  
Steffen Flacke ◽  
Marco Liserre
Keyword(s):  
High Frequency ◽  
Current Control ◽  
Grid Current ◽  
Frequency Grid

Performance of Pulsating High-Frequency Current Injection Based Sensorless Control of PMSM

2013 ◽  
Vol 347-350 ◽  
pp. 610-616
Author(s):  
Jian Min Wang
Keyword(s):  
High Frequency ◽  
Sensorless Control ◽  
Tracking Error ◽  
Position Estimation ◽  
Current Control ◽  
Current Injection ◽  
High Frequency Current ◽  
Position Errors ◽  
Pulsating Current ◽  
Frequency Current

In the paper the principle and performances of the pulsating current injection based sensorless control of permanent magnet synchronous motor (PMSM) are analyzed theoretically and investigated by simulations. In the analyses, the effects of the speed EMF terms and the deviation between the actual d-axis high-frequency current and the command, which results from the limited gain and bandwidth of the current control loop, are all taken into account. It is shown that the pulsating current injection method can achieve stable position estimation in a wide speed range. But appreciable position errors will result at high speeds due to the cross-coupling effects of the speed EMFs and the tracking error between the actual and command carrier current. In order to improve the performance, a modified scheme is proposed. Its validity is confirmed by simulations.

scholarly journals A single-phase DC-AC dual-active-bridge based resonant converter for grid-connected photovoltaic applications

2021 ◽  
Author(s):  
Marcos Felix Aguirre
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
Current Control ◽  
Energy Resources ◽  
Voltage Source ◽  
Resonant Circuit ◽  
Renewable Energy Resources ◽  
Grid Voltage ◽  
Dual Active Bridge ◽  
Averaged Models

In the wake of the global energy crisis, the integration of renewable energy resources, energy storage devices, and electric vehicles into the electric grid has been of great interest towards replacing conventional, fossil-fuel-dependent energy resources. This thesis presents the circuit topology and a control strategy for a 250-W single-phase gridconnected dc-ac converter for photovoltaic (PV) solar applications. The converter is based on the dual active bridge (DAB) kernel employing a series-resonant link and a high-frequency isolation stage. For interfacing the 60-Hz ac grid with the 78-kHz resonant circuit, the converter utilizes a four-quadrant switch array that functions as an ac-ac stage. Therefore, a bipolar low-frequency voltage source, that is the grid voltage, is used to synthesize a symmetrical high-frequency voltage pulse-train for the resonant circuit. Thus, soft switching and the use of a compact ferrite-core transformer have been possible. Then, a fast current-control loop ensures that the converter injects a sinusoidal current in phase with the grid voltage, while a relatively slower feedback loop regulates the converter dc-side voltage, that is, the PV array voltage, at a desired value. To simulate the converter and to design the controllers, the thesis also presents nonlinear large-signal and linearized small-signal state-space averaged models. The performance of the converter is assessed through simulation studies conducted using the aforementioned averaged models, a detailed topological model in the PLECS software environment, and a prototype. Keywords: Photovoltaic, PV, Microinverter, Dual Active Bridge, Phase-shift Modulation, High Frequency Transformer

Analysis of Fast-Scale Bifurcation in Peak Current Controlled Buck-Boost Inverter Based on Unified Averaged Model

2016 ◽  
Vol 26 (05) ◽  
pp. 1650074 ◽  
Author(s):  
Hao Zhang ◽  
Shuai Dong ◽  
Weimin Guan ◽  
Ye Liu
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Period Doubling ◽  
Current Control ◽  
High Frequency Oscillation ◽  
Switching Frequency ◽  
Unified Framework ◽  
Frequency Oscillation ◽  
Peak Current ◽  
Averaged Model

In this paper, a unified averaged modeling method is proposed to investigate the fast-scale period-doubling bifurcation of a full-bridge integrated buck-boost inverter with peak current control. In order to increase the resolution of the conventional classic averaged model to half the switching frequency, sample-and-hold effect of inductor current is absorbed into the averaged model, i.e. the proposed unified averaged model can capture the high-frequency dynamical characteristics of the buck-boost inverter, which is both an extension and a modification of conventional averaged model. Based on the unified mode, fast-scale bifurcation is identified, and the corresponding bifurcation point is predicted with the help of the locus movement of all the poles, and their underlying mechanisms are revealed. Detailed analysis shows that the occurrence of high-frequency oscillation means fast-scale bifurcation, while the occurrence of low-frequency oscillation leads to slow-scale bifurcation. Finally, it is demonstrated that the unified averaged model can provide not only a general method to investigate both the slow- and fast-scale bifurcations in a unified framework but also a quite straightforward design-oriented method which can be directly applicable.

Design and Analysis of a Photovoltaic Power System with Bi-Directional Inverter

2013 ◽  
Vol 291-294 ◽  
pp. 9-13
Author(s):  
De Han Luo ◽  
Yu En Wu ◽  
Qiang Li
Keyword(s):  
Power System ◽  
High Frequency ◽  
Current Control ◽  
High Current ◽  
Single Chip ◽  
Current Harmonic ◽  
Grid Connection ◽  
Photovoltaic Power ◽  
Buffer Power ◽  
Analysis Design

This paper presents the analysis, design, and simulation of a photovoltaic power system with bi-directional inverter, which can be controlled with a single-chip microcontroller, such as dsPIC30F4011. The bi-directional inverter can fulfill grid connection and rectification with power factor correction to regulate the dc bus to a certain range of voltages. So, it will no need energy storage elements to buffer power. But the two stage series can cause high current harmonic, so a predictive current control and modulation principle for the bi-directional inverter is designed and operated in high frequency to reduce the current harmonic. Simulation and experimental results have illustrated the discussed features and significantly demonstrated its feasibility, reliability, and stability.

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