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Relative binding free energy calculations in drug design are becoming a useful tool in facilitating lead binding affinity optimization in a cost- and time-efficient manner. However, they have been limited by technical challenges such as the manual creation of large numbers of input files to set up, run, and analyze free energy simulations. In this Application Note, we describe FEPrepare, a novel web-based tool, which automates the setup procedure for relative binding FEP calculations for the dual-topology scheme of NAMD, one of the major MD engines, using OPLS-AA force field topology and parameter files. FEPrepare provides the user with all necessary files needed to run a FEP/MD simulation with NAMD. FEPrepare can be accessed and used at https://feprepare.vi-seem.eu/.

This paper presents a novel control scheme for a distribution static compensator (DSTATCOM) aimed at mitigating voltage sag at the Point of Common Coupling (PCC) or eliminating current harmonics of the load. The proposed control scheme uses the d – q reference frame for the decoupling of active and reactive current components. Furthermore a selective algorithm is integrated to the control scheme in order to choose between the voltage support mode or the current harmonics elimination mode. Finally, the DSTATCOM is based on a three phase three level flying capacitor topology. The proposed control scheme outperforms the conventional one due to the ability of the suggested control system to combine multiple functions, allowing DSTATCOM to respond in various power quality issues. The effectiveness of the proposed control scheme to enhance the multifunction ability of the DSTATCOM is verified via Matlab/Simulink© in both steady state and transient response.

In this paper, a photovoltaic (PV) system, with maximum power point tracking (MPPT), connected to a three phase grid is presented. The connection of photovoltaic system on the grid takes place in one stage using voltage source inverter (VSI). For a better utilization of the photovoltaic system, the control strategy applied is based on p–q theory. According to this strategy during sunlight the system sends active power to the grid and at the same time compensates the reactive power of the load. In case there is no sunlight (during the night for instance), the inverter only compensates the reactive power of the load. In this paper the use of p–q theory to supply the grid with active power and compensate the reactive power of the load is investigated. The advantage of this control strategy is that the photovoltaic system is operated the whole day. Furthermore, the p–q theory uses simple algebraic calculations without demanding the use of PLL to synchronize the inverter with the grid.

In this paper, a photovoltaic (P/V) system, with maximum power point tracking (MPPT), connected to a three phase grid is presented. The connection of photovoltaic system on the grid takes place in one stage using voltage source inverter (VSI). For a better utilization of the photovoltaic system, the control strategy applied is based on p-q theory. According to this strategy during sunlight the system sends active power to the grid and at the same time compensates the reactive power of the load. In case there is no sunlight (during the night for instance), the inverter only compensates the reactive power of the load. The advantage of this strategy is the operation of the photovoltaic system the whole day. In this paper the p-q theory is proposed, which does not demand the use of PLL and introduces simple algebraic calculations.

In this paper the impact of photovoltaic (PV) system connected to the medium voltage distribution grid using three-phase three-level inverter and step-up transformer will be investigated. The PV inverter is capable to control active and reactive power independently. The impact to the grid voltage profile of both active and reactive power regulation of the PV system will be examined. In order to simplify the control scheme and improve the performance of the converters the p-q theory has been chosen due to the ability to compensate the reactive power of the load. The proposed electric power system was investigated via simulation results during steady state and transient response. The analysis will be focused on the grid voltage profile improvement regarding of the of the inverter's active and reactive power injection.

This paper presents a shunt active filter which eliminates current harmonics and compensates the reactive power of the load. The majority of shunt active power filter control methods which have been presented require a complex and sophisticated mathematical model, especially for the tuning of the PI controllers. To simplify and improve the shunt active filter control system, fuzzy logic theory is applied. In this paper, by the way of controlling the capacitor voltage of the dc bus a fuzzy logic algorithm is implemented. One such algorithm is also implemented to control the output current of the inverter. The performance of the capacitor voltage fuzzy logic control system was investigated, and the improvement of the dynamic response of the fuzzy controller compared to the conventional PI controller became evident. For the reduction of the grid current THDi index, a fuzzy logic hysteresis current controller is investigated. In order to improve the performance of shunt active filter under non ideal grid voltages, a modified version of the p-q theory is proposed. The simulation results are presented and discussed showing the advantages of fuzzy logic theory in the dc bus voltage control and current control.

In this paper the connection in single stage single phase of a photovoltaic system (PV) to the electric power system is presented. A modified version of p-q theory is proposed in order to implement this strategy in a single phase inverter. To extract maximum power from the PV array an algorithm Maximum Power Point Tracking (MPPT) is used. For the switching pattern generation the hysteresis controller is used. The behavior of both the permanent and the transient state, which includes changing the radiation and the load is analyzed using a computer.

This paper investigates the operation of a Distributed Generation (DG) unit which is connected via a three-phase voltage-source inverter to the distribution grid. The current control method with Space Vector pulse width modulation (SVPWM) is examined and compared to other current control methods. The strategy, which has been developed to control the reactive power and have a better utilization of DG unit, uses the p-q theory to achieve uninterrupted compensation of the reactive power of the system. A PI controller is used to control the active power and regulate the voltage of the capacitor. Finally, the proposed electrical power system is simulated on the computer and the steady-state and dynamic response of the system is evaluated.

In this paper the problems created by non linear load as well as the solutions having been applied so far are briefly reviewed. A new simple and effective reference current generation method of a shunt active power filter (SAPF) is proposed. This method aims at eliminating harmonics from the mains currents. It also compensates the reactive power which is created from the linear and non linear loads. The new method is applied both in the case that mains voltages are ideal and in the case that mains voltages are non ideal. The new method is compared to the conventional p-q theory and the results are analyzed and commented on. From the analysis and the commentary the advantages of the new technique are concluded.

This paper initially refers to the devices used to compensate upper harmonics. Subsequently, it examines the principal methods for controlling an active filter which is connected to the electricity grid in order to compensate reactive power and to eliminate the electricity harmonics. The mathematic model following the p-q theory is analyzed for the creation of a reference current, aiming at the elimination of the upper harmonics and at reactive power compensation. An improved control method is presented regarding current control through the use of a Hysteresis Band with an altering tolerance band. In this way, current control is adjusted onto the load current.

One of the fundamental drawbacks of the conventional LCL resonant inductive power transfer (IPT) system is the inverter highly distorted ac-current. As a consequence, the on-state and switching losses are increased. In order to overcome these disadvantages, this paper introduces an improved IPT system. The proposed improvement comprises notch filters, along with LCL filter in the inverter side of the IPT system. The performance of the conventional and the proposed IPT system is verified by simulation results. Heavy load and light load operation conditions are taken into account. In the end, a detailed power loss analysis of the inverter is presented for both IPT systems. Simulation results as well as power loss analysis verify that the proposed IPT system reduces the switching losses, the on-state losses, the RMS value and the total harmonic distortion of the converter current.