Control Strategy For Photovoltaic System Research Articles

Optimal control strategy of photovoltaic system based autonomous micro grid for power quality improvement

<span>Due to the increasing number of distributed generation units being used in remote regions, the need for reliable and flexible operation of these systems has led to the development of microgrid technology. When a microgrid operates in an autonomous mode, it can experience unpredictable loads and other factors that can affect its operation. An optimal control mechanism is required to maintain the system's stability. Hence, in this paper optimal control strategy of autonomous microgrid for power quality improvement is presented. A test case of single phase 3.5 kW photovoltaic (PV) system based autonomous micro grid is considered. Particle swarm optimization (PSO) and Harris hawks optimization (HHO) optimal control strategies are implemented under standard test case and variable test cases. In all the cases </span><span lang="EN-IN">PV mean voltage-</span><span>Vmpv (V), </span><span>PV mean current</span><span>-</span><span>Impv (A), </span><span>RMS voltage-</span><span>Vrms (V), </span><span>RMS current-</span><span>Irms (A), </span><span>mean PV power-Ppv </span><span>(W), </span><span>autonomous grid power-</span><span>Pg (W)</span><span>, efficiency (%), total harmonic distortion (THD) (%), inverter losses (%) are evaluated. In all the cases HHO optimal control strategy for autonomous microgrid exhibits the best performance in comparison with PSO optimal control strategy. The inverter efficiency is improved, inverter losses are reduced and the THD is improved.</span>

Research on coordinated control strategy of photovoltaic energy storage system

In this paper, the modular design is adopted to study the control strategy of photovoltaic system, energy storage system and flexible DC system, so as to achieve the design and control strategy research of the whole system of “photovoltaic + energy storage + DC + flexible DC”. This realizes the flexibility and diversity of networking. Due to space reasons, this article focuses on the detailed explanation of the photovoltaic energy storage system control strategy, including the maximum power tracking control strategy of photovoltaic power generation, photovoltaic power generation boost chopper circuit control strategy, photovoltaic power generation DC/AC converter control strategy, PCS device control strategy, PCS virtual impedance control algorithm, etc. Simulation experiments are carried out according to the specific case setting parameters. The simulation results prove that the proposed flexible DC system coordinated control strategy can ensure grid frequency stability and grid voltage stability, and improve the consumption capacity of distributed new energy.

INFLUENCE OF THE SAMPLING FREQUENCY ON VARIOUS MAXIMUM POWER POINT TRACKING COMMANDS

The present work continues the previous article published in the International Journal of Energy (Elsevier, 2019). Our previous study aimed to develop a new and innovative method based on neural network algorithms to predict an instantaneous command. A new control strategy for photovoltaic systems was presented in [1]. This command is based on the neuronal network (NN) technique. To the best of our knowledge, this technique has never been used in this field for that objective. The authors of this work used it to synthesize control laws for electronic power converters.It should be noted that the newly designed algorithm based on neural networks is expected to be more robust with a good performance concerning tracking speed and precision. Moreover, the present research work aims at providing a robust neural structure against noisy empirical data, thus allowing the prediction of a new command. Indeed, in the present work, we will examine the parameters affecting four MPPT controls in addition to the new neural network-based algorithm developed in [1].

A Double-Layer Voltage Control Model for Distributed Photovoltaic in Distribution Network

With the increasing penetration of distributed photovoltaic (PV) in distribution network (DN), and the randomness of PV power output, so the DN with PV is prone to voltage fluctuation or even overvoltage. In this paper, a double-layer distributed PV voltage control strategy is proposed. This strategy takes full advantage of reactive power of PV inverter connected to DN and aims at reducing the loss of uploading power of PV, so as to achieve collaborative control of buses voltage. It adopts the double-layer control strategy of PV system in DN, as well as the three modes switching of maximum power point tracking (MPPT), reactive power regulating and power factor regulating of PV. On the premise of realizing the effective control of buses voltage, it can reduce the loss of uploading power of PV to the greatest extent. Finally, the proposed distributed PV voltage control strategy is verified through a typical DN case based on the real time digital simulation (RTDS).

Flexible Active Power Control Strategy for Photovoltaic System Based on Current Limiting Control Method

India is country with abundant solar energy availability. The annual solar energy output exceeds the total energy output of India's non renewable energy sources. As increasing installation of renewable energy sources into the grid. The fluctuations of power based on operating climate conditions like solar insulation and temperature is highly depends as it is not possible to limit such installations with time the penetration level of renewable sources will increase to meet demand with green energy. This paper proposed a flexibly power point tracking (FPPT) control of active power in photovoltaic system to achieve reserve capacity with Power Limiting Control (PLC) which will provide high stability to existing system without overloading it thus a proper integration to the grid and to mitigate adverse negative effects of high level integrations are possible with modified grid codes in stand of replacement of existing grid . Matlab/Simulink software package is used to make the model and effectiveness of the propose system is tested with Simulink environment..

Control Strategy of Photovoltaic System to Regulate Active and Reactive Power during Unbalanced Grid Voltages by Using Fuzzy Logic Control

The advanced reactive power regulation is planned to direct the highest and the voltages at least point of regular pairing inside the cutoff points set up in grid codes for consistent operation. These work displays a regulating technique to which the grid associated PV system meaning to direct the power of both active and reactive infused to the electrical system amid the voltage faults that are uneven in nature. Fuzzy controller is propel controller which is for the most part appropriate for the personal fundamental guidance tool. which additionally gave the electronic system operation by the master choice. The reference of active power is acquired from a Maximum Power Point Tracking (MPPT) calculation. The advanced force methodology creates the necessary reference currents that forced by the grid-tied inverter from the coveted P and Q powers and the deliberate voltage supply. In unequal voltage sags, positive and negative sequence KVAr are consolidated to adaptable boost and even out the phase voltages; maximum phase voltage is controlled below as far as possible and the base phase voltage simply over as far as possible. The plan is approved to a solitary step PV system where the currents that are regulated by means of prescient control. By using the fuzzy controller for a nonlinear system which permit the decrease for the questionable impact in the system which control and impeccably enhance the effectiveness. Results demonstrating the execution of the procedure are introduced amid uneven sags and swells.

PV System Control to Provide Active Power Reserves Under Partial Shading Conditions

The challenges of modern power systems will inevitably impose increased ancillary service requirements to photovoltaic (PV) plants in the future, including operating reserves. Recent studies have investigated methods to maintain active power reserves without energy storage in the standard case of uniform illumination. In this paper, this functionality is extended to partial shading conditions, often encountered in PV systems. A new control scheme is proposed that permits operation at a reduced power level, estimating at the same time the shading conditions and maximum available power. This is achieved by applying a least-squares curve fitting algorithm on voltage and current measurements, without relying on any irradiance or temperature sensors. To the best of our knowledge, this is the first power reserves control scheme for PV systems under partial shading presented in the literature. The robustness and effectiveness of the proposed method are validated under rapidly changing shading conditions through simulations and experimental tests on a 2-kW PV system prototype.

A coordinated frequency control strategy for photovoltaic system in microgrid

This paper proposes a coordinated DC-link voltage control and deloading control for two-stage PV system to offer frequency support in an islanded microgrid without energy storage system(ESS). The e...

An advanced control strategy of PV system for low-voltage ride-through capability enhancement

This paper presents a novel control strategy of the two-stage three-phase photovoltaic (PV) system to improve the low-voltage ride-through (LVRT) capability according to the grid connection requirement. With the help of the new strategy, the PV array can generate active power as much as possible according to the depth of the grid voltage dip and the power rating of the grid inverter to keep power balance between the two sides of the inverter by operating in different modes. It is worthy of special mention that the proposed strategy can ensure the reactive power support when a low voltage fault occurs at the point of common coupling (PCC) without additional device. Besides, the new control method introduces a feed forward compensation reflecting the instantaneous current injecting into the DC-link from the PV array to smooth the DC-link voltage fluctuations during the grid fault. The effectiveness of the proposed control strategy has been demonstrated through various simulation scenarios. Compared with the conventional protection, the proposed control strategy can not only enhance the LVRT capability of the PV system, but also provide grid support through the active and reactive power control.

Power control strategy for photovoltaic system based on the Newton quadratic interpolation

To maximise the economic benefit, photovoltaic (PV) systems in general operate in the so-called maximum power point tracking (MPPT) mode. However, in certain occasions (e.g. in a microgrid or in a weak system), it is beneficial for a PV system not to always operate in the MPPT mode, but occasionally in the power dispatch mode, because of the top priority of maintaining system stability. To this end, a Newton quadratic interpolation-based power control strategy for PV system is proposed to iteratively obtain the required terminal voltage of PV system by approximating the power–voltage characteristic curve with a quadratic curve. With this control strategy, PV systems can operate in the power dispatch mode to flexibly adjust the active power output in a wide range, or adaptively switch to the MPPT mode if necessary. Details on the convergence rate and the way to achieve the fault ride-through capability are also discussed. Simulation is performed based on a detailed PV dynamical model, illustrating that the proposed method has fast convergence rate and robust performance compared with a revised perturb and observe method which can attain the same function.