Direct Sliding Mode Control for Dynamic Instabilities in DC-Link Voltage of Standalone Photovoltaic Systems with a Small Capacitor

Large electrolytic capacitors used in grid-connected and stand-alone photovoltaic (PV) applications for power decoupling purposes are unreliable because of their short lifetime. Film capacitors can be used instead of electrolytic capacitors if the energy storage requirement of the power conditioning units (PCUs) is reduced, since they offer better reliability and have a longer lifetime. Film capacitors have a lower capacitance than electrolytic capacitors, causing enormous frequency ripples on the DC-link voltage and affecting the standalone photovoltaic system’s dynamic performance. This research provided novel direct sliding mode controllers (DSMCs) for minimizing DC-link capacitor, regulating various components of the PV/BES system that assists to manage the DC-link voltage with a small capacitor. DSMCs were combined with the perturb and observe (P&O) method for DC boost converters to increase the photovoltaic system’s dynamic performance, and regulate the battery’s bidirectional converter (BDC) to overcome the DC-link voltage instabilities caused via a lower DC-link capacitor. The system is intended to power both AC and DC loads in places without grid connection. The system’s functions are divided into four modes, dependent on energy supply and demand, and the battery’s state of charge. The findings illustrate the controllers’ durability and the system’s outstanding performance. The testing was carried out on the MT real-time control platform NI PXIE-1071 utilizing Hardware-In-The-Loop experiments and MATLAB/Simulink.

Simulation of Bidirectional Converter for Vechile to Grid and Grid to Vechile Application

This paper represents a bidirectional converter for the application of vehicle to grid and grid to vehicle application. This converter can be used in the application of electric vehicle. And the results have been verified through simulation in MATLAB. The topology can provide an energy bi-directional flow path for energy exchange between the Libattery/supercapacitor (SC) hybrid energy storage system (HESS) of the electric vehicle and the grid. Keywords: bi-directional converter, vehicle, HESS, Li-battery.

Design of a High Efficiency High Step-Up/Step-Down Bidirectional Isolated DC–DC Converter

This paper presents a novel bidirectional DC–DC converter, equipped with a three-winding coupled inductor, that can be applied to high-voltage, bidirectional DC–DC energy conversion and meet battery charging and discharging requirements. The architecture consists of a semi-Z-source converter and a forward–flyback converter featuring a three-winding coupled inductor with an iron core. This proposed topology retains the current continuity characteristics of the low-voltage side, all switches possess the zero-voltage switching feature, and the switches on the low-voltage side in the step-down mode have a synchronous rectification function. A 500-W bidirectional converter is implemented to examine the practicality and feasibility of the proposed topology. The relatively streamlined design of the converter can greatly reduce production costs. In the step-up and step-down modes, the maximum energy conversion efficiencies are 95.74% and 96.13%, respectively.

Energy Management of a Renewable Hybrid Isolated DC Microgrid

Hybrid microgrid is the key solution to energize remote rural areas. The microgrid system incorporates more than one Distributed Renewable Energy (DRE) source to complement one another. This paper proposes a hybrid DC microgrid system to be operated in isolated mode. The proposed microgrid consists of a PMSG based Wind Turbine, PV array, and Lead-acid battery as an energy storage device. The Wind Turbine generator is connected to the DC bus through a Three-phase Diode Bridge Rectifier. The PV array is tied to the DC bus by a Boost converter and incremental conductance algorithm is used to extract the maximum power from the PV array. The battery uses a bidirectional converter for charging and discharging. A simple PI-based closed-loop control system is incorporated for proper energy management. The bus voltage is maintained either by the boost converter or the bidirectional converter depending upon the operating condition. The proposed microgrid system is modeled in MATLAB/SIMULINK software. Simulation of this model is done for varying irradiance, temperature, wind condition, and different load condition. The simulation results show that the system is stable under various load and supply conditions. Keywords: Hybrid microgrid, Distributed Renewable Energy (DRE), PMSG, PV array, DC bus, Boost converter, incremental conductance, bidirectional converter

Design of Controller for Electrical Vehicle to Grid Power

This paper prescribed the design of controller for electrical vehicle to Grid power, by using this controller improve the power requirement of grid and reactive power compensation capability. Bidirectional converter is very helpful during on peak load demand. During off peak load demand grid will supply the power to the battery and charge the battery. During on peak load demand excess power of battery will supply to the grid. The concept aggregator is depicted in the figure 2. (Aggregator collects the power from all electrical vehicle first then it supply to the grid). This modern electrical vehicle technology proposed the distribution generation Methodology. All the control strategies of modern electrical vehicle to grid is proposed like smart charging or discharging of batteries during off peak load demand and On peak load demand respectively. V2G controller allow the active power it act as an ancillary services to grid. Electrical vehicle controller has ability to exchange the active or reactive power capability. Simulation of bidirectional AC/DC and DC/DC controller and their control circuit are analyzed by using matlab Simulink software.

Modelling and Analysis of Power Electronic Converters for EV Charging/Discharging for G2V, V2G and V2X Operations

The research work deals with the implementation of various chargers used for electric vehicles in the context of Qatar. These chargers are categorized as slow, fast, and super-fast chargers. The electric vehicles not only lead to a reduction in carbon footprint, but the V2X mode of operation of EVs implemented with the help of a bidirectional converter is used to provide ancillary services in the system such as shaving peak and valley in load demand, frequency, and voltage regulation, balance the supply and demand for active power and reactive power, compensate grid current harmonics, improve power quality, provide reactive power compensation and improve system stability. Due to the above-mentioned advantages, V2X mode of operation will be explored in this research work.