WavePacket: A Matlab package for numerical quantum dynamics. III: Quantum-classical simulations and surface hopping trajectories

WavePacket is an open-source program package for numerical simulations in quantum dynamics. Building on the previous Part I [Comp. Phys. Comm. 213, 223-234 (2017)] and Part II [Comp. Phys. Comm. 228, 229-244 (2018)] which dealt with quantum dynamics of closed and open systems, respectively, the present Part III adds fully classical and mixed quantum-classical propagations to WavePacket. In those simulations classical phase-space densities are sampled by trajectories which follow (diabatic or adiabatic) potential energy surfaces. In the vicinity of (genuine or avoided) intersections of those surfaces trajectories may switch between surfaces. To model these transitions, two classes of stochastic algorithms have been implemented: (1) J. C. Tully's fewest switches surface hopping and (2) Landau-Zener based single switch surface hopping. The latter one offers the advantage of being based on adiabatic energy gaps only, thus not requiring non-adiabatic coupling information any more. The present work describes the MATLAB version of WavePacket 6.0.2 which is essentially an object-oriented rewrite of previous versions, allowing to perform fully classical, quantum-classical and quantum-mechanical simulations on an equal footing, i.e., for the same physical system described by the same WavePacket input. The software package is hosted and further developed at the Sourceforge platform, where also extensive Wiki-documentation as well as numerous worked-out demonstration examples with animated graphics are available

Model Predictive Observer Based Control for Single-Phase Asymmetrical T-Type AC/DC Power Converter

© 1972-2012 IEEE. This paper presents a robust control strategy for the control of single-phase five-level asymmetrical T-type ac/dc power converter. A cascaded control scheme consisting of a finite control set model predictive control (FCS-MPC) with an extended state observer (ESO) is proposed to govern the converter. In this scheme, a proportional integral (PI) controller combined with an ESO-based disturbance observer is employed as an external control loop. This control loop dynamically modifies the active power reference to realize the desired operating point of the system state (converter output voltage). The proposed control system presents a high degree of disturbance rejection capability and robustness against the external disturbances to the converter, whereas the conventional PI control performance suffers in the presence of these disturbances. In this paper, the inner current tracking loop is accomplished by an FCS-MPC algorithm. This algorithm is derived to force the input currents to track the reference values while realizing a user-defined reactive power and maintaining balanced voltages in the series-connected capacitors. Theoretical analysis and the design procedure of the proposed control system are presented. Finally, experimental studies are conducted to verify the effectiveness of the proposed control scheme

Model predictive control applied to a single phase seven-level active rectifier

© 2017 IEEE. This paper presents an improved single phase seven-level active rectifier architecture controlled by finite control set model predictive control (FCS-MPC). The FCS-MPC is designed to enable power conversion with a unity power factor and generate seven level voltage waveform at the input. The proposed active rectifier architecture reduces harmonic contents of the rectifier input current by producing different voltage levels at the rectifier input. Owing to the architecture and multilevel operation, it reduces the EMI filter size, input current harmonic, the voltage rating on devices and switching losses that are lower than those of conventional three-level rectifier topologies. The proposed converter can also be operated as a multilevel inverter. Extensive simulation results are presented to verify the proposed converter when the load changes, the reference active and reactive power changes

A high efficiency transformerless PV grid- Connected inverter with leakage current suppression

© 2016 IEEE. This paper presents a new diode free freewheeling and common-mode voltage (CMV) clamping branches for single phase transformerless grid connected photovoltaic (PV) inverter for complete leakage current elimination and low conduction losses. In the past, various isolation techniques have been proposed for leakage current elimination in transformerless PV inverters. However, galvanic isolation only cannot completely eliminate leakage current due to that a resonant path is created by the switch junction capacitors, which also generate leakage current. The proposed freewheeling branch consists of four MOSFETs along with a clamping branch, which consists of two MOSFETs and a capacitor divider. The divider is connected to the DC side of the converter to keep constant CMV in the freewheeling path. As a result, the improved CMV clamping has been achieved for complete leakage current elimination. The unipolar sinusoidal pulse width modulation (SPWM) technique and modified HERIC topology with AC-decoupling for galvanic isolation is adopted for lower conduction losses. The proposed topology consists of only MOSFET in the freewheeling and clamping path which provides lower conduction losses compared with diode based topologies. The performances of the proposed topology in terms of common mode characteristics, leakage current, total harmonic distortion and conversion efficiency are analyzed and compared with H5, H6, HERIC and HBZBR topologies. The detail analyses are performed using MATLAB/Simulink and PSIM