Frequency Scanning-Based Contributions Identification of Current Control Loop and PLL on DQ Impedance Characteristics of Three-Phase Grid-Connected Inverter

2020 ◽  
Author(s):  
Weihua Zhou ◽  
Yanbo Wang ◽  
Raymundo E. Torres-Olguin ◽  
Zhe Chen
Keyword(s):  
Current Control ◽  
Control Loop ◽  
Frequency Scanning ◽  
Impedance Characteristics ◽  
Three Phase ◽  
Grid Connected Inverter

Three-Level Grid-Connected Inverter Based on Voltage-Oriented Control in Photovoltaic Generation Systems

2013 ◽  
Vol 765-767 ◽  
pp. 2494-2497
Author(s):  
Fang Ping Zhao ◽  
Yong Yang
Keyword(s):  
Current Control ◽  
Control Loop ◽  
Unity Power Factor ◽  
Photovoltaic Generation ◽  
Pwm Inverter ◽  
Pulse Width Modulated ◽  
Three Phase ◽  
Control Scheme ◽  
Grid Connected Inverter ◽  
Power Point

The paper propose a new control of a three-phase three-level neutral-point-clamped (NPC) pulse width modulated (PWM) inverter in photovoltaic generation systems. The control scheme is mainly based on voltage-oriented control (VOC) with an improved maximum power point (MPP) tracking (MPPT). A cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous dq reference frame using a decoupled feedback control. Furthermore, in order to achieve a unity power factor, the q-axis current reference is set to zero. The experimental results have proven an excellent performance and verified the validity of proposed system.

scholarly journals A Decoupled Hybrid Current Control for Improving the Performance of 60° DPWM-Based Three-Phase Grid-Connected Inverter

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 876-888
Author(s):  
Yuanbin He ◽  
Bangchao Wang ◽  
Xiaogao Xie ◽  
Lei Shen ◽  
Pingliang Zeng
Keyword(s):  
Current Control ◽  
Three Phase ◽  
Grid Connected Inverter

scholarly journals Coupling Influence on the dq Impedance Stability Analysis for the Three-Phase Grid-Connected Inverter

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3676
Author(s):  
Chuanyue Li ◽  
Taoufik Qoria ◽  
Frederic Colas ◽  
Jun Liang ◽  
Wenlong Ming ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Nyquist Plot ◽  
Current Control ◽  
Impedance Ratio ◽  
Three Phase ◽  
Grid Impedance ◽  
Nyquist Criterion ◽  
Grid Connected Inverter ◽  
The Stability ◽  
The Right

The dq impedance stability analysis for a grid-connected current-control inverter is based on the impedance ratio matrix. However, the coupled matrix brings difficulties in deriving its eigenvalues for the analysis based on the general Nyquist criterion. If the couplings are ignored for simplification, unacceptable errors will be present in the analysis. In this paper, the influence of the couplings on the dq impedance stability analysis is studied. To take the couplings into account simply, the determinant-based impedance stability analysis is used. The mechanism between the determinant of the impedance-ratio matrix and the inverter stability is unveiled. Compared to the eigenvalues-based analysis, only one determinant rather than two eigenvalue s-function is required for the stability analysis. One Nyquist plot or pole map can be applied to the determinant to check the right-half-plane poles. The accuracy of the determinant-based stability analysis is also checked by comparing with the state-space stability analysis method. For the stability analysis, the coupling influence on the current control, the phase-locked loop, and the grid impedance are studied. The errors can be 10% in the stability analysis if the couplings are ignored.

Design and Implementation of 30kW Three-Phase PV Grid-Connected Inverter

2012 ◽  
Vol 241-244 ◽  
pp. 636-640
Author(s):  
Wu Wu Tang ◽  
Liang Liang Chen ◽  
Hong Xu Yin ◽  
Hao Dong
Keyword(s):  
Control Method ◽  
Dynamic Performance ◽  
Current Control ◽  
Unity Power Factor ◽  
Harmonic Content ◽  
Three Phase ◽  
Rotating Reference Frame ◽  
Grid Connected Inverter ◽  
Pv Grid ◽  
Factor State

This paper developed a mathematical model of three-phase PV grid-connected inverter, and studied the grid-connected current control method based on PI control in synchronous rotating reference frame. Simulation and experimental results from the prototype of 30kW three-phase PV grid-connected inverter proved the correctness and the feasibility of the control strategy, and this grid-connected inverter can operate at the unity power factor state with a nice dynamic performance, and the output current has high sinusoidal and low harmonic content as well as good symmetry.

scholarly journals Discrete-Time DC-Link Voltage and Current Control of a Grid-Connected Inverter with LCL-Filter and Very Small DC-Link Capacitance

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5613 ◽  
Author(s):  
Oliver Kalmbach ◽  
Christian Dirscherl ◽  
Christoph M. Hackl
Keyword(s):  
Discrete Time ◽  
Controller Design ◽  
Linear Quadratic Regulator ◽  
Current Control ◽  
Control Loop ◽  
Linear Quadratic ◽  
Lcl Filter ◽  
Current Controller ◽  
Voltage Controller ◽  
Grid Connected Inverter

The paper presents a controller design for grid-connected inverters (GCI) with very small dc-link capacitance that are coupled to the grid via an LCL filter. The usual controller designs would fail and result in instability. The proposed controller has a cascaded structure with a current controller as inner control loop and an outer dc-link voltage controller. The controller design is performed in discrete time and it is based on a detailed stability analysis of the dc-link voltage controller to determine the controller parameters which guarantee stability for all operating points. The inner loop is a state-feedback current controller that is designed based on the discrete linear-quadratic regulator (DLQR) theory. An additional integral error feedback assures steady-state accuracy of the current control loop. The simulation and experimental results validate performance and stability of proposed controller design.

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