Single phase gird connected inverter based on one-cycle current control

Author(s):  
Xiaoyong Ji ◽  
Ting Zhang ◽  
Hongyang Su ◽  
Zezhong Xia ◽  
Zhi Tang ◽  
...  
Keyword(s):  
Author(s):  
Yong Yang ◽  
Jianyu Pan ◽  
Huiqing Wen ◽  
Mingdi Fan ◽  
Rong Chen ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3230
Author(s):  
Milovan Majstorovic ◽  
Marco Rivera ◽  
Leposava Ristic ◽  
Patrick Wheeler

The operation of single-phase Modular Multilevel Converter (MMC) is analyzed in the paper. A mathematical model of the converter is developed and described, based on which the structure and selection of parameters for Classical Control and Optimal Switching State Model Predictive Control (OSS-MPC) are defined. Additionally, the procedure for the determination of circuit parameters, such as submodule capacitance and arm inductance, is described and carried out. The listed control methods are designed and evaluated in Virtual Hardware-in-the-Loop together with single-phase MMC power circuit, regarding three control objectives: AC current control, voltage balancing control and circulating current control. Control methods are evaluated for both steady-state and transient performance and compared based on nine criteria: AC current reference tracking, THD of AC current and voltage, submodule capacitor voltage balancing, total submodule voltage control, circulating current magnitude and THD, number of control parameters and computational complexity. This is the first time that a fair comparison between Classical Control and MPC is considered in literature, resulting in superior performance of both control methods regarding four different criteria and the same performance regarding AC current reference tracking.


2019 ◽  
Vol 8 (4) ◽  
pp. 2814-2822

This paper projects a high performance decoupled current control using a dq synchronous reference frame for single-phase inverter. For the three-phase inverter the conversion from AC to DC with Proportional Integral controller grants to obtain steady state error for AC Voltages and currents but has a few challenges with the single-phase systems. Hence, an orthogonal pair (β) is created by shifting the phase by one quarter cycle with respect to the real component (α) which is needed for the transformation from stationary to rotating frame. The synchronous reference frame control theory helps in controlling the AC voltage by using DC signal as the reference with the proportional integrator controllers. The implementation of the control is done with two-stage converter with LCL filter for a single-phase photovoltaic system. A modified MPPT Incremental conductance algorithm along with decoupled current control helps in regulating the active and reactive power infused into the grid where the power factor is improved, the efficiency of the system is increased above 95% and total harmonic distortion for current is also reduced to3%. The results have been validated using MATLAB.


2021 ◽  
Author(s):  
Marcos Felix Aguirre

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


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