A single-stage grid-connected inverter with wide range reactive power compensation using energy storage system (ESS)

Author(s):  
Liming Liu ◽  
Zhichao Wu ◽  
Hui Li
Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1365
Author(s):  
Mukul Chankaya ◽  
Ikhlaq Hussain ◽  
Aijaz Ahmad ◽  
Irfan Khan ◽  
S.M. Muyeen

This paper presents Nyström minimum kernel risk-sensitive loss (NysMKRSL) based control of a three-phase four-wire grid-tied dual-stage PV-hybrid energy storage system, under varying conditions such as irradiation variation, unbalanced load, and abnormal grid voltage. The Voltage Source Converter (VSC) control enables the system to perform multifunctional operations such as reactive power compensation, load balancing, power balancing, and harmonics elimination while maintaining Unity Power Factor (UPF). The proposed VSC control delivers more accurate weights with fewer oscillations, hence reducing overall losses and providing better stability to the system. The seamless control with the Hybrid Energy Storage System (HESS) facilitates the system’s grid-tied and isolated operation. The HESS includes the battery, fuel cell, and ultra-capacitor to accomplish the peak shaving, managing the disturbances of sudden and prolonged nature occurring due to load unbalancing and abnormal grid voltage. The DC link voltage is regulated by tuning the PI controller gains utilizing the Salp Swarm Optimization (SSO) algorithm to stabilize the system with minimum deviation from the reference voltage, during various simulated dynamic conditions. The optimized DC bus control generates the accurate loss component of current, which further enhances the performance of the proposed VSC control. The presented system was simulated in the MATLAB 2016a environment and performed satisfactorily as per IEEE 519 standards.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1121
Author(s):  
Rozmysław Mieński ◽  
Przemysław Urbanek ◽  
Irena Wasiak

The paper includes the analysis of the operation of low-voltage prosumer installation consisting of receivers and electricity sources and equipped with a 3-phase energy storage system. The aim of the storage application is the management of active power within the installation to decrease the total power exchanged with the supplying network and thus reduce energy costs borne by the prosumer. A solution for the effective implementation of the storage system is presented. Apart from the active power management performed according to the prosumer’s needs, the storage inverter provides the ancillary service of voltage regulation in the network according to the requirements of the network operator. A control strategy involving algorithms for voltage regulation without prejudice to the prosumer’s interest is described in the paper. Reactive power is used first as a control signal and if the required voltage effect cannot be reached, then the active power in the controlled phase is additionally changed and the Energy Storage System (ESS) loading is redistributed in phases in such a way that the total active power set by the prosumer program remains unchanged. The efficiency of the control strategy was tested by means of a simulation model in the PSCAD/EMTDC program. The results of the simulations are presented.


2021 ◽  
Vol 69 (2) ◽  
pp. 5-12
Author(s):  
Zheng Li ◽  
Yan Qin ◽  
Xin Cao ◽  
Shaodong Hou ◽  
Hexu Sun

In order to meet the load demand of power system, BP based on genetic algorithm is applied to the typical daily load forecasting in summer. The demand change of summer load is analysed. Simulation results show the accuracy of the algorithm. In terms of power supply, the reserves of fossil energy are drying up. According to the prediction of authoritative organizations, the world's coal can be mined for 216 years. As a renewable energy, wind power has no carbon emissions compared with traditional fossil energy. At present, it is generally believed that wind energy and solar energy are green power in the full sense, and they are inexhaustible clean power. The model of wind power solar hydrogen hybrid energy system is established. The control strategy of battery power compensation for delayed power of hydrogen production is adopted, and different operation modes are divided. The simulation results show that the system considering the control strategy can well meet the load demand. Battery energy storage system is difficult to respond to short-term peak power fluctuations. Super capacitor is used to suppress it. This paper studies the battery supercapacitor complementary energy storage system and its control strategy. When the line impedance of each generation unit in power grid is not equal, its output reactive power will be affected by the line impedance and distributed unevenly. A droop coefficient selection method of reactive power sharing is proposed. Energy storage device is needed to balance power and maintain DC voltage stability in the DC side of microgrid. Therefore, a new droop control strategy is proposed. By detecting the DC voltage, dynamically translating the droop characteristic curve, adjusting the output power, maintaining the DC voltage in a reasonable range, reducing the capacity of the DC side energy storage device. Photovoltaic grid connected inverter chooses the new droop control strategy.


Author(s):  
Maheswar Prasad Behera ◽  
Pravat Kumar Ray

Abstract The feasibility of integration of Battery Energy Storage System (BESS) with a three-phase AC grid is being investigated in this paper. A converter is an inevitable part of a modern DC generating system. The link between the grid and the BESS is established through a Voltage Source Converter (VSC). Therefore, the converter can be utilized to dispatch the DC generated power to the connected AC grid and at the same time provides reactive power compensation and load harmonic compensation throughout the day. The DC bus voltage control of the converter system is carried out to keep the power factor always at unity, irrespective of the charging state of the battery source. The charging and discharging of the connected battery energy storage system are carried out through a bidirectional DC-DC converter. Adaptive hysteresis band current control (AHCC) scheme is employed to produce the switching signals. Finally, its performance is compared with the traditional hysteresis band control technique.


Author(s):  
D.V.N. Ananth ◽  
G.V. Nagesh Kumar

In this paper, enhanced field oriented control technique (EFOC) was adopted in Rotor Side Control (RSC) of DFIG converter for improved response during severe faults. The work is intended to damp pulsations in electromagnetic torque, improve voltage mitigation and limit surge currents and to enhance the operation of DFIG during voltage sags. The converter topology uses a battery energy storage system with capacitor storage system to further enhance operation of DFIG during faults. The battery and capacitor system in coordination provide additional real and reactive power support during faults and nearly constant voltage profile at stator and rotor terminals and limit overcurrents. For EFOC technique, rotor flux reference changes its value from synchronous speed to zero during fault for injecting current at the rotor slip frequency. In this process DC-Offset component of flux is controlled, decomposition during overvoltage faults. The offset decomposition of flux will be oscillatory in a conventional FOC, whereas in EFOC it will damp quickly. A comparison is made with proposed methodology with battery energy storage system and a conventional system. Later the system performance with under voltage of 50% the rated voltage with fault at PCC during 0.8 to 1.2 seconds is analysed using simulation studies.


Author(s):  
Shobhana Singh ◽  
Kim Sørensen

Abstract In the present paper, a high-temperature packed bed energy storage system of volume 175,000m3 is numerically investigated. The system is a underground packed bed of truncated conical shape, which comprises of rocks as a storage medium and air as a heat transfer fluid. A one-dimensional, two-phase model is developed to simulate the transient behavior of the storage. The developed model is used to conduct a parametric study with a wide range of design parameters to investigate the change in performance during both charging and discharging operation. Results show that the model satisfactorily predicts the dynamic behavior, and the truncated conical shaped storage with a rock diameter of 3cm, insulation thickness up to 0.6m and charging-discharging rate of 553kg/s leads to lower thermal losses and higher energy efficiencies. The paper provides useful insight into the transient performance and efficiency of a large-scale packed bed energy storage system within the range of parameters investigated.


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