Simulation of three-phase grid tied inverter (original) (raw)
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Inverter grid synchronization-A review and Simulation
This paper represents the review, simulation and results of inverter grid synchronization. The converter i.e. three phase voltage source inverter is the most important part to use the renewable energy sources. The method use for inverter grid synchronization is the phase locked loop (PLL). In order to synchronize the inverter with grid in terms of voltage, frequency and phase the MATLAB SIMULINK is used. This paper also summarizes and compares different methods of synchronization in literature review section. Sinusoidal Pulse Width Modulation (SPWM) technology is also described in this paper. This method overcomes the low performance of conventional pulse width modulation technique which is use for active filter. Various simulation result are also presented to show the effectiveness of phase locked loop.
IJERT-Synchronization of Three Phase Inverter with Electrical Grid
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/synchronization-of-three-phase-inverter-with-electrical-grid https://www.ijert.org/research/synchronization-of-three-phase-inverter-with-electrical-grid-IJERTV4IS050938.pdf Phase, frequency, and amplitude of phase voltages are the most important and basic parameters need to be controlled or grid-connected applications. The aim of this paper is to present a review of various synchronization techniques for pulse width modulated voltage source inverter. This paper describes the estimation method and verifies its usefulness by extensive numerical experiments. Various synchronization algorithms are described here. The primary application of the proposed synchronization methods is for the distributed generation units with renewable energy sources, which utilize power electronic converters as an integral part of their systems. The synchronization is usually carried out with respect to the voltage, frequency and phase angle of voltage (or current) signal(s) of the utility system. The paper also describes the issues, challenges & solutions for. Index Terms-Microgrid, Inverter, Synchronization, Amplitude, frequency and phase control. I.INTRODUCTION A Microgrid is an aggregation of multiple distributed generators (DGs), such as renewable energy sources, conventional generators, and energy storage systems etc. Typically, a Microgrid operates in parallel with the main grid. However, in some situation a Microgrid need to operate in an islanded mode, or in a standalone state. Islanded distributed generators (DGs) in a Microgrid can change its operational mode to grid connected operation by reconnection to the grid, which is referred to as synchronization. A Microgrid or a portion of the power grid which consists of load and distributed generator (DG) system; it can be isolated from Grid. In this situation, it is important for the Microgrid to continue to provide adequate power to the load under standard supply conditions. In various circumstances, if fault conditions occur in the grid, then the Microgrid is expected to isolate from the main grid, each distributed generators (DGs) of inverter system must detect this islanding situation and must switch to a voltage control mode. However, the synchronization of Microgrids that operate with multiple distributed generators (DGs) and loads cannot be controlled by a traditional synchronizer. It is needed to control multiple generators and energy storage systems in a coordinated way for the Microgrid synchronization. In ideal condition, the output voltage parameters like amplitude, frequency and phase cannot be controlled for a grid together where multiple DGs are working in parallel; whereas the same parameters for sand alone inverter to be connected to grid, can be controlled by means of the various control strategies[1]-[8]. In order to provide the required load voltage, inverter system works in standalone mode or grid connected mode. In load scheduling condition or grid off condition, the inverters works in standalone mode and provide the required power to the load. Being major of the power available through renewable systems is in DC form, inverters are preferred instead of alternators. Parameters of the inverter such as voltage, frequency and phase can be controlled for the purpose of synchronization with the relevant parameters of the grid system. Synchronization of inverter parameters like voltage, frequency and phase with grid systems can be possible by specific control system with embedded controller. To meet the load sharing requirement, the output from the inverter system can be varied with synchronization of grid system. The system presented here is a DC to AC inverter controlled using a compact controller based on an embedded system and that can be synchronized with the grid system [9]-[12]. Various techniques of synchronization of the inverter are described in the second section named as literature review. Proposed system for synchronization of inverter with electrical grid is described in Methodology section. Experimentation and Results are discussed in next section. II.LITERATURE REVIEW In sinusoidal pulse width modulation, there are multiple pulses per half-cycle and the width of the each pulse is varied with respect to the sine wave magnitude. Pure sine wave DC/AC conversion will introduce the least amount of harmonics into an electrical system, but these methods are also expensive. Since the AC sine wave to come from a DC source, the static devices will be switched in a logical way such that the energy delivered to a load approaches that of a pure sine wave. This means that extra components and design considerations are involved in the control circuitry of a pure sine wave inverter, driving up cost. A more precise method of DC/AC conversion is the modified sine wave, which introduces a dead time in a normal square wave output so that higher peak voltages can be used to produce the same average voltage as a sinusoidal output. This method produces fewer harmonics than square wave generation, but it still is not quite the same as the AC power that comes from an AC
A New Synchronization Technique of a Three-Phase Grid Tied Inverter for Photovoltaic Applications
Mathematical Problems in Engineering, 2018
Three-phase grid synchronization is one of the main techniques of the three-phase grid connected power inverters used in photovoltaic systems. This technique was used to reach the fast and accurate three-phase grid tied inverter synchronization. In this paper a new synchronization method is presented on the basis of integrating the grid voltage two times (line-to-line or phase voltage). This method can be called “double integral synchronization method” (DISM) as it integrates the grid voltage signals two times to generate the reference signals of three-phase photovoltaic inverter currents. DISM is designed and simulated in this paper to operate in both analog and digital circuits of three-phase photovoltaic inverter system with the same topology. The digital circuit design and dsPIC33FJ256GP710A as a microcontroller (the dsPIC33FJ256GP710A with the Explorer 16 Development Board from microchip) was used practically in this paper to generate and control the sine pulse width modulation...
A Synchronization Method for Single-Phase Grid-Tied Inverters
IEEE Transactions on Power Electronics, 2015
The controllers of single-phase grid-tied inverters require improvements to enable distribution generation systems to meet the grid codes/standards with respect to power quality and the fault ride through capability. In that case, the response of the selected synchronization technique is crucial for the performance of the entire grid-tied inverter. In this paper, a new synchronization method with good dynamics and high accuracy under a highly distorted voltage is proposed. This method uses a Multi-Harmonic Decoupling Cell (MHDC), which thus can cancel out the oscillations on the synchronization signals due to the harmonic voltage distortion while maintaining the dynamic response of the synchronization. Therefore, the accurate and dynamic response of the proposed MHDC-PLL can be beneficial for the performance of the whole single-phase grid-tied inverter.
Renewable Energy Focus, 2017
In this paper, an overview of grid-connected renewable systems is presented, then two current-control strategies for 3-phase grid-connected inverters are analyzed: firstly, the well-known d-q control in the rotating synchronous reference frame (d-q axes) using Proportional Integral regulators is described, and secondly, the Proportional Resonant controller in the Stationary Reference Frame (ab axes). In order to obtain a high efficiency of the system when the 3-phase utility grid voltages are affected by harmonic pollution, a Harmonic Compensator (HC) structure is used with the Proportional Resonant controller, this due to the ease way to compensate harmonics when a Proportional Resonant control is utilized instead of a d-q control. Then both control strategies (d-q control and PR + HC) are analyzed under harmonic pollution condition. For both strategies, a Positive Sequence Detector plus a Synchronous Reference Frame Phase-Look Loop (PSD + dqPLL) is used as the synchronization algorithm. After the study, it was observed that the PR controller provides a greater facility for carrying out the harmonic compensation process helping to fulfill with the international standards. A model of a grid-connected photovoltaic system with a nominal power of 10 kW is used to evaluate and compare the performance of the current-control strategies. For this, a Real-Time Digital Simulator (RTDS) platform is used.
Investigation on Grid Synchronization for Grid-Tied DC-AC Single Phase Inverters
2014 International Conference on Computer and Communication Engineering, 2014
This paper presents a single-phase Grid-tied inverter for renewable energy systems, which can be used for obtaining small-voltage AC supply for powering small electronic devices or can be used in a distributed grid system for utility supply. The issue of synchronization of these DC-AC inverters with the grid/utility systems is explained and investigated thoroughly in this research. The waveforms generated by each stage of inverter is shown and the issue of power loss caused by variation in phase and frequency due to inaccurate zero crossings is also shown and discussed.
Simulation and implementation of grid-connected inverters
Solar, wind and hydro are renewable energy sources that are seen as reliable alternatives to conventional energy sources such as oil or natural gas. However, the efficiency and the performance of renewable energy systems are still under development. Consequently, the control structures of the gridconnected inverter as an important section for energy conversion and transmission should be improved to meet the requirements for grid interconnection. In this paper, a comprehensive simulation and implementation of a threephase grid-connected inverter is presented. The control structure of the grid-side inverter is firstly discussed. Secondly, the space vector modulation SVM is presented. Thirdly, the synchronization for grid-connected inverters is discussed. Finally, the simulation of the grid-connected inverter system using PSIM simulation package and the system implementation are presented to illustrate concepts and compare their results.
Aalborg Universitet Improved control strategy for the three-phase grid-connected inverter
An improved control strategy for the three-phase grid-connected inverter with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axis grid currents will be interacted, and then the waveform quality of the grid current will be poorer. As the reference output voltage cannot directly reflect the change of the reference grid current, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axis grid currents in the decoupled components of the grid current controller can be substituted by the d-and q-axis reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated.
IEEE 36th Conference on Power Electronics Specialists, 2005., 2005
This paper proposes a new open-loop synchronization method for three-phase three-wire PWM converters connected to the utility grid. It presents a better performance in terms of distortions in the synchronism signals if compared with other open-loop methods. Moreover, it has a good transient performance due to both angle and frequency disturbances, as well as input currents with low total harmonic distortion (THD) when used to synchronize PWM rectifiers, even under unbalanced and highly distorted grid voltages. In addition, a frequency adaptation algorithm is proposed for applications where large frequency variations are expected, such as in weak grids. Experimental results using a DSP TMS320F2812 are given to demonstrate the good performance of the proposed synchronism method.
Performance Analysis and Simulation of a Three Phase Grid Tie Inverter
IJIREEICE
This paper analyses the performance of a three phase grid tie inverter through simulation. The converter current controller is based on synchronous reference frame and d-q transformation which provides the reference voltage signal for the desired converter output voltage. The Sinusoidal Pulse Width Modulation generates firing pulses for six MOSFETs of the three phase full wave bridge converter and inturn regulates the active and reactive power flow of the converter. The dynamic variation in the voltage of DC source is neglected and hence DC voltage is held constant. The DC bus current is controlled by varying active current reference Iq ref. Accordingly the DC source can absorb or supply active power by varying Iq ref of the controller. The performance evaluation of three phase grid tie inverter for active power interaction while providing reactive power support is carried out in the present work.