This work presents an enhanced second-order generalized integrator (ESOGI) based control method for the grid integrated unified power quality conditioner (UPQC) with a solar photovoltaic (PV) system. ...The objective of this work is to improve the power quality (PQ) indices in the grid by eliminating voltage sensors (grid side) in the overall control. Moreover, presented control method effectively eliminates the DC offset from the input signals and estimates the fundamental element (FE), which is processed to compute the reference signals. The UPQC-PV system comprises two voltage source converters, one connected in a parallel at the point of common coupling for load compensation and the other connected in series via an injecting transformer for voltage compensation. The comparative performance is demonstrated in this work to validate the effectiveness of presented control over state-of-art control algorithms. Moreover, the cost analysis of the presented control is also discussed with the traditional controllers. The UPQC-PV system is simulated in Simulink tool of MATLAB and the performances are analyzed at various dynamic scenarios such as load unbalancing; distorted grid voltages; symmetrical and asymmetrical voltages swell and sag; and change in solar insolation, etc. Experimental results illustrate the superior performance under various operating conditions. The harmonics and magnitudes of load side voltages are restricted as per the IEEE standard 1159. The grid currents and load voltages are well sinusoidal with their total harmonic distortions in the permissible range state in the IEEE standard 519.
This article presents a battery integrated photovoltaic (PV) system, which maintains grid interconnection at adverse grid conditions. Additionally, sinusoidal and balanced grid currents are achieved ...under grid voltage distortions, unbalanced grid voltages, and unbalanced load currents, using the presented modified second order sequence filter (MSOSF). The MSOSF eliminates DC offset in the sensed control signals. The DC-DC boost converter ensures the optimum PV array power utilization. A bi-directional DC-DC converter (BDC) is suitably controlled for the BESS (battery energy storage system) charging and discharging. The developed control strategy draws several operational benefits from the BESS. The intermittencies in the grid power at the variations in PV array power and local loads are eliminated. The grid disconnection encountered in conventional systems at large voltage drops is mitigated and the system provides continued support to the utility. At overvoltage situations, the utility is assisted by ceasing power export while permitting power inflow from the utility. In contrast to conventional systems, no PV array de-rating is necessitated. The injected grid power is a function of the prevailing feed-in tariffs, thereby ensuring greater economic benefits and helps to flatten the demand side power curve. The BESS health is conserved by transition to a recovery operation, on detection of over-charge or over-discharge conditions. Performance of the system at various operating situations is evaluated in detail using test results derived from a prototype developed in the laboratory.
In this article, a solar photovoltaic (PV) array, a battery energy storage (BES), a diesel generator (DG) set, and a grid-based electric vehicle (EV) charging station (CS) is utilized to provide the ...incessant charging in islanded, grid-connected, and DG set connected modes. The CS is primarily designed to use the solar PV array and a BES to charge the EV battery. However, in case of exhausted storage battery and unavailable solar PV array generation, the CS intelligently takes power from the grid or DG set. However, the power from DG set is drawn in a manner that it always operates at 80%-85% loading to achieve maximum fuel efficiency under all loading conditions. Moreover, in coordination with the storage battery, the CS regulates the generator voltage and frequency without a mechanical speed governor. It also ensures that the power drawn from the grid or the DG set is at unity power factor even at nonlinear loading. Moreover, the point of common coupling voltage is synchronized to the grid/generator voltage to obtain the ceaseless charging. The CS also performs the vehicle to grid active/reactive power transfer, vehicle to home, and vehicle-to-vehicle power transfer for increasing the operational efficiency of the CS. The operation of the CS is experimentally validated using the prototype developed in the laboratory.
This paper deals with a Cuk dc-dc converter as a single-stage power-factor-correction converter for a permanent-magnet (PM) brushless dc motor (PMBLDCM) fed through a diode bridge rectifier from a ...single-phase ac mains. A three-phase voltage-source inverter is used as an electronic commutator to operate the PMBLDCM driving an air-conditioner compressor. The speed of the compressor is controlled to achieve optimum air-conditioning using a concept of the voltage control at dc link proportional to the desired speed of the PMBLDCM. The stator currents of the PMBLDCM during step change in the reference speed are controlled within the specified limits by an addition of a rate limiter in the reference dc link voltage. The proposed PMBLDCM drive (PMBLDCMD) is designed and modeled, and its performance is evaluated in Matlab-Simulink environment. Simulated results are presented to demonstrate an improved power quality at ac mains of the PMBLDCMD system in a wide range of speed and input ac voltage. Test results of a developed controller are also presented to validate the design and model of the drive.
This article presents a three-phase, single-stage photovoltaic (PV) system with a battery energy storage (BES) that functions in both grid-tied and islanded modes. In grid-tied mode, dual-mode ...PV-battery system (DPBS) provides functionalities such as reactive power compensation, enhanced power quality (PQ), and feeding PV power to utility. On grid loss, it acts as an uninterrupted supply and maintains load voltage. To provide above features, a dual-mode controller is designed with cascaded adaptive vectorial filter control along with maximum power point tracking (MPPT) in grid-tied mode and voltage control in islanded mode. Moreover, a robust dual-loop adaptive notch filter-based phase-locked loop (PLL) with a hybrid islanding detection mechanism monitors grid and coordinates grid re/connection and isolation, adhering to IEEE 1547-2018 revised standard. A laboratory prototype of DPBS has operated successfully in different test scenarios.
A multiport power electronic transformer based on cascaded H-bridge (CHB) converter with split battery energy storage (BES) units is a viable solution for fast electric vehicle (EV) charging station, ...eliminating the need for line-frequency transformers and reducing the influence of charging station on distribution grid. In the absence of bulky CHB module capacitors or LC secondary resonant filters in CHB converter, second-order frequency power ripple impacts the controllability of the overall system, and the lifetime of BES units as well as EV batteries. In state-of-the-art, electronic capacitor (EC) is employed in single-phase PFC converters to deal with 2<inline-formula><tex-math notation="LaTeX">{\text{nd}}</tex-math></inline-formula> ripple issue, however, its implementation in CHB converters leads to increased switch requirements and losses. Therefore, this work introduces an integrated EC (IEC)-based isolated dc-dc converter for each conversion-chain, to reduce the CHB module capacitance requirement without using extra switches. Derived from a buck-based EC and isolated dc-dc converter, IEC diverts second-order frequency power ripple into decoupling storage capacitance, while maintaining the desired output power. In addition, in off-grid mode, where split BES's supply power to EV batteries, the IEC functions as a bidirectional isolated dc-dc converter. Moreover, the principle of operation of all modes, zero-voltage switching conditions in grid-connected mode, and associated functions are also discussed in this article. Proof-of-concept of IEC-based fast EV charging station is verified with simulation results. Finally, hardware results are provided using a developed downscaled single-conversion chain prototype of IEC.
In this paper, a Volterra-filter-based control algorithm is developed to generate reference currents for a solar photovoltaic-distribution static compensator (PV-DSTATCOM) system in the distribution ...network. The developed control is analyzed for being stable under Lyapunov stability criterion; consequently, the error function of the system converges to zero asymptotically. The PV-DSTATCOM system is integrated to the grid to compensate the nonlinear load, while supplying solar PV array active power to the grid. The system is modeled in MATLAB and is executed on a developed prototype in the laboratory, under balanced, unbalanced loading conditions, and variable insolation conditions. Moreover, the harmonic distortion of the grid currents is observed under the IEEE-519 standard.
Hand tremors (HT) are common involuntary shaking movements of the hand. The development of a method for its suppression is a serious concern for researchers and medical practitioners. Currently, ...managing tremors involves lifestyle adjustments, medication, or surgery. However, these treatments have drawbacks. Long-term use of medication often leads to negative side effects, and its effectiveness diminishes over time. Surgical interventions like deep brain stimulation (invasive) or thalamotomy (non-invasive) are expensive, risky, and can result in irreversible brain lesions. As a result, alternative therapies have been developed. The mathematical models of HT systems that play a significant role in the development of tremor suppression devices, controllers, and other interventions are complex and of high dimension. Designing controllers for such models becomes tedious and costly. It is, therefore, obvious to develop a procedure that tackles these issues and reduces cost and complexity. For this purpose, a model simplification-based method has been proposed herein. In the proposed method, a lower-dimensional biodynamic model (LDBM) of order l is derived from a higher-dimensional biodynamical system (HDBS) of order h. A PID controller is obtained for this LDBM, which is subsequently applied to the HDBS. The improved Routh-Padé simplification method is used for finding LDBM in which first l time moments (TM)/Markov parameter (MP) of HDBS are retained in LDBM and errors between the set of next TM/MP of the HDBS and LDBM are minimized using Luss-Jaakola (LJ) optimization algorithm. The effectiveness of the present method has been confirmed by an illustrative example.
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•The concept of model reduction is introduced for suppression of hand tremors (HT).•To the best of authors’s knowledge, Routh-Padé approximants (RPA) are used for the first time for HT suppression.•The controller derived via RPA shows satisfactory performance.
Environmental pollution and fossil fuel usage have attracted attention and opportunities in marine industry. The rapid advancement of solar technology and corresponding cost reduction have resulted ...in the use of solar photovoltaic (SPV) systems in vessels. The intermittent nature of SPV arrays necessitates a battery as an energy storage. The presence of a diesel generator (DG), propulsion motor drive, auxiliary nonlinear loads, and sources with power converter interfaces deteriorate power quality of shipboard microgrid. Therefore, an enhanced fractional least mean square (EFLMS) filtering scheme is utilized in proposed microgrid to enhance power quality. A modified double second-order generalized integrator (MDSOGI) based quasi-type-1 phase-locked loop (QT1-PLL) synchronizes DG set and shipboard microgrid. This article eliminates mechanical sensors for propulsion motor drive and thus adopts an enhanced cascaded second-order generalized integrator (ECSOGI) for its sensorless position estimation. Gazelle-optimized tuned proportional-integral ensures a better regulation of DC bus voltages. Power management system (PMS) is established to schedule generations and loads while ensuring minimal DG set utilization. The analysis of shipboard microgrid is performed in MATLAB/Simulink platform and validated in a real-time simulator.
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