Singe-Phase Grid-Connected Inverter Based on Voltage-Oriented Control in Photovoltaic Generation Systems

2013 ◽  
Vol 765-767 ◽  
pp. 2498-2502
Author(s):  
Yong Yang ◽  
Chun Qing Qi ◽  
Ji Suo ◽  
Feng Wen Cao
Keyword(s):  
Feedback Control ◽  
Reference Frame ◽  
Single Phase ◽  
Control Structure ◽  
Current Control ◽  
Control Loop ◽  
Excellent Performance ◽  
Photovoltaic Generation ◽  
Control Scheme ◽  
Grid Connected Inverter

The paper proposes a new control of a transformerless singe-stage single-phase grid-connected inverter in photovoltaic generation systems. The control scheme is mainly based on voltage-oriented control (VOC) with help of second order Generalized Integrator (SOGI). 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. The simulated results have proven an excellent performance and verified the validity of proposed system.

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 Stationary Reference Frame Current Control Algorithm for Improvement of Transient Dynamics of a Single Phase Grid Connected Inverter

Electronics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 722 ◽  
Author(s):  
Horyeong Jeong ◽  
Jae Suk Lee
Keyword(s):  
Reference Frame ◽  
Disturbance Rejection ◽  
Control Algorithm ◽  
Single Phase ◽  
Current Control ◽  
Phase Lag ◽  
Phase Current ◽  
Disturbance Rejection Control ◽  
Stationary Reference Frame ◽  
Grid Connected Inverter

This paper proposes a stationary reference frame current control algorithm for a single-phase grid-connected inverter (GCI) for improvement of transient dynamic performance. Disturbance, i.e., grid voltage in a target system, is estimated using a stator current observer, and the estimated disturbance is applied to a current controller for implementation of disturbance rejection control (DRC). In the proposed current control algorithm, the disturbance rejection control algorithm is applied to reduce the overcurrent occurring in the single-phase grid-connected inverter when grid faults happen. In this paper, the AC phase current of a single-phase inverter is controlled, instead of the current vector, which is a DC signal. To compensate for the drawbacks of controlling the AC phase current, such as phase lag and steady-state error, command feedforward control is also applied in the proposed control system. The proposed control algorithm is mathematically derived and represented in transfer functions and implemented via simulation and experiment.

scholarly journals Current Control and Active Damping for Single Phase LCL-Filtered Grid Connected Inverter

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Mohammad Alshiekh ◽  
Alaa Marouf ◽  
Muhieddin Kubeitari
Keyword(s):  
Current Control ◽  
Active Damping ◽  
System Stability ◽  
Switching Frequency ◽  
Control Loop ◽  
Passive Element ◽  
Lcl Filter ◽  
Control Scheme ◽  
Grid Connected Inverter ◽  
Filter Capacitor

LCL filter has been widely used in the grid connected inverter, since it is effective in attenuation of the switching frequency harmonics in the inverter. However, the resonance in this filter causes stability problems and must be damped effectively to achieve stability. There are some methods to damp the resonance; one method is passive damping of resonance by adding a series resistor with the filter capacitor, but passive element reduces the inverter efficiency. Other method uses active damping (AD) by adding a proportional control loop of filter capacitor current, but this method needs additional sensor to measure filter capacitor current; moreover, when the control loops are digitally implemented, the computation delay in AD control loop will lead to some difficulties in choosing control parameters and maintaining system stability. This paper presents current control scheme for the grid connected inverter with the LCL filter. The proposed scheme ensures the control of injected current into grid with AD of the resonance in the LCL filter while keeping system stability and eliminating the effect of computation delay of the AD loop. An estimation of filter capacitor current with one step ahead is performed using the discrete time observer based on measuring the injected current. This reduces the cost and increases the robustness of the system. Proportional Resonant (PR) controller is used to control the injected current. Design of control system and choosing its parameters are studied and justified in details to ensure suitable performance with adequate stability margins. Simulation and experimental results show the effectiveness and the robustness of the proposed control scheme.

scholarly journals A DQ Synchronous Reference Frame Current Control for Grid Connected Photovoltaic Systems usingSingle Phase Cascaded H Bridge Multilevel Inverter

2019 ◽  
Vol 8 (4) ◽  
pp. 2814-2822
Keyword(s):  
Reference Frame ◽  
High Performance ◽  
Single Phase ◽  
Reactive Power ◽  
Current Control ◽  
Photovoltaic System ◽  
Real Component ◽  
Phase Inverter ◽  
Synchronous Reference Frame ◽  
Single Phase Inverter

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.

Implementation of Single-Phase Two-Switch Midpoint Unidirectional Multilevel Converter System

2018 ◽  
Vol 19 (4) ◽  
Author(s):  
Peethala Rajiv Roy ◽  
P. Parthiban ◽  
B. Chitti Babu
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Open Loop ◽  
Current Control ◽  
Control Technique ◽  
Control Scheme

Abstract This paper deals with implementation of a single-phase three level converter system under low voltage condition. The frequency of the switches is made constant and involves change in ${t_{on}}$ and ${t_{off}}$ duration. For this condition the pulse width modulation control scheme for a single phase three level rectifier is developed to improve the power quality. The hysteresis current control technique is adopted to bring forth three-level PWM on the dc side of the bridge rectifier and to achieve high power factor and low harmonic distortion. Based on the proposed control scheme, the line current is driven to follow the sinusoidal current command which is in phase with the supply voltage. By using three-level voltage pattern the blocking voltage of each power device is clamped to half of the dc link voltage. The simulation and experimental results of 20W converter under low input voltage condition are shown to verify the circuit performance. Open loop simulation and hardware tests are implemented by applying a low voltage of 15 V(rms) on the input side.

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