Single Stage Solar Photovoltaic Array Research Articles

Performance Assessment of Three-Phase NPC-Based Grid Integrated Single-Stage Solar PV System With Reduced DC Bus Capacitor

This work proposes an effective reduction in the capacitor size of the DC-bus of a conventional three-phase neutral point clamped (NPC) inverter-based grid integrated single-stage solar photovoltaic (PV) system. This has been done by implementing a metallized polypropylene film DC-bus capacitor instead of an electrolytic capacitor. As an outcome, this enhances the system's long-term reliability, reduces cost, and increases the system's life expectancy. The unbalance in capacitor voltage due to a small DC-bus capacitor is also identified. As a solution, a carrier-based modified modulation strategy is implemented to improve the dynamic response of neutral-point voltage. A single-stage solar PV array is utilized in this paper. An optimal power extraction (OPE) scheme is adopted to extract solar PV power. The DC-bus voltage overshoot issue that arises during the change in irradiation is resolved, and minimal oscillations are observed. The implemented scheme allows the feeding of the extracted power to the three-phase grid via the NPC converter, which in turn diminishes the total harmonic distortion (THD) of the grid. The PI controller minimizes the voltage and current error. The system performance is observed using a MATLAB version simulation model and authenticated through the experimental results obtained from the laboratory prototype.

Implementation of Solar Photovoltaic Grid Interfaced System Using Improved Second Order Generalised Integrator Quadrature (ISOGI-Q) Algorithm

This article deals with a single-stage solar photo voltaic (SPV) array tied toward a three-phase grid by means of an improved second-order generalised integrator quadrature (ISOGI-Q)-based control algorithm to develop the power quality of the grid. The maximum point power tracking (MPPT) is achieved by using a perturb and observe method (P&O). P&O MPPT technique is efficient to extract additional power commencing an SPV array and easy. The SOGI-Q based control serves multi functionalities for example load balancing, power factor correction as well as enhanced solar power penetration addicted to a distribution network. Investigation consequences of the SOGI-Q-based control algorithm are found to be adequate in favour of enhanced power quality in conditions of load balancing, harmonics elimination with very effective power factor correction under different dynamic conditions for instance load unbalancing, variable solar insolation, distorted grid along with imbalanced grid voltage conditions. Distributed static compensator capabilities of a SPV-based system are functional to supply the active power to the load as well as surplus power to the grid.

Grid Integration of Single-Stage SPV-STATCOM System Using Symmetric Cascaded Five-Level VSC

This work proposes a dual-function single-stage solar photovoltaic (SPV) grid-tied system with STATCOM (static compensator) capabilities using a three-phase five-level cascaded VSC (voltage source converter) operating at low switching frequency with low total harmonic distortion (THD) and low switching losses. The proposed SPV-STATCOM system works in three modes: i.e. Mode-1, in which only an active power is transferred to the grid, Mode-2, in which both active and reactive power are supplied to the grid and Mode-3, in which only reactive power is supplied to the grid, thereby utilizing the full capabilities of the SPV system. An incremental conductance algorithm is used to track power from SPV array which is fed to the grid. To synchronize the VSC to the grid, a decoupled current controller with feed-forward term and double decoupled synchronous reference frame phase-locked loop (DDSRF-PLL) is used. The use of a single-stage five-level cascaded VSC offers the advantages of low switching losses and the operation at high power and high voltage which results in an improvement in quality of power of the system. The simulated results demonstrate the system design and control scheme under varying conditions.

An Adaptive Control Scheme of SPV System Integrated to AC Distribution System

This paper presents a single-stage solar photovoltaic (SPV) system utilizing an adaptive control scheme. The SPV system includes SPV array, voltage source converter (VSC), ripple filter, nonlinear loads, and a distribution network. The proposed SPV system feeds the active power to the distribution system, provides an effective use of SPV array and mitigation of load harmonics currents. The SPV system with an incremental conductance based control scheme is used for obtaining the maximum power from the SPV array and an adaptive control scheme to control the switching pulses of the VSC. In addition, it utilizes a SPV feed-forward loop to improve the dynamic response and reduces the burden on the proportional-integral controller by regulating dc bus voltage. Test results are presented to validate the control, design, and response of SPV system with various states.

Real‐time implementation of three‐phase single‐stage SPV grid‐tied system using TL‐VSC

This work deals with real-time implementation of a three-phase single-stage solar photovoltaic (SPV) grid-tied system using a three-level voltage source converter (TL-VSC) working at lower switching frequency of 900 Hz under varying solar intensity levels for large power applications. The proposed system consists of SPV array, TL-VSC, interfacing inductors, and three-phase AC grid. The decoupled current controller with the capacitor voltage balancing control and an incremental conductance maximum power point tracking (IC-MPPT)-based algorithms are used to control the TL-VSC to track and transfer maximum active power to AC grid at unity power factor from SPV array. Owing to low switching frequency and single-stage topology, the efficacy of the system is increased. The performance of SPV grid integrated system using TL-VSC is validated under varying solar intensity levels in the laboratory at different switching frequencies and interfacing inductors in accordance to IEEE 519 standard.

Single‐phase solar grid‐interfaced system with active filtering using adaptive linear combiner filter‐based control scheme

This study deals with a control scheme for single-stage solar photovoltaic (SPV) grid-interfaced system. The voltage-source inverter (VSI) is a power electronic interface between SPV array and the grid. The VSI provides power quality features, i.e. harmonics mitigation, power factor correction and perturb and observe maximum power point tracking for single-stage SPV grid-interfaced system. The SPV array supplies active power to the non-linear load and grid through VSI, during daytime only or when SPV generation is more than the load power. To increase the utilisation of VSI, it is used as an active power filter at night, to mitigate harmonics and to provide active power to the load from the utility grid. The proposed adaptive linear combiner filter has the capability to extract harmonics and enhances the power quality in SPV grid-interfaced system. It has also satisfied an IEEE-519 standard of harmonics by improving the quality of power of SPV grid-integrated system. Simulation results of the SPV system are presented, which are simulated using MATLAB and response of system under non-linear load and varying environmental condition are also studied experimentally on a developed prototype in the laboratory.

Adaptive neuron detection‐based control of single‐phase SPV grid integrated system with active filtering

This study deals with an adaptive neuron detection-based control technique for single-phase, single-stage solar photovoltaic (SPV) array grid integrated system using a voltage-source converter (VSC). The VSC also provides power quality features such as harmonics mitigation, power factor correction and perturb and observation-based maximum power point tracking for an SPV grid-interfaced system. With this approach, the VSC has the active power flow from the SPV array to the grid and it also performs the non-linear load current harmonic compensation by keeping the grid current almost sinusoidal. On the other hand, in the night mode, if the SPV power is not available, the VSC works as an active power filter for the harmonics elimination and reactive power compensation. This increases the effective utilisation of the VSC. The adaptive neuron detection technique has lesser noise and oscillation in extraction of fundamental component in comparison of conventional adaptive control algorithm. It has also satisfied an IEEE-519 standard of harmonics by improving the quality of power of SPV grid integrated system. The proposed system is modelled and simulated using MATLAB/Simulink and the response of the system under non-linear loads and varying environmental conditions are evaluated experimentally on a prototype developed in the laboratory.