Data Structures and Sparsity in a Digital Simulation of an HVDC Link

An earlier algorithm for the detailed simulation of the High Voltage Direct Current (HVDC) link using the tensor approach was modified to improve the runtime speed. The runtime, approximately eleven percent that of the original algorithm, was improved by employing sparsity techniques, restructuring the state matrix, and condensing subroutines. The readability of the code was accomplished by a modular programming approach. This research was done for a two-terminal simulation, but could be expanded and modified to include multiterminal simulations

Reduced order multirate schemes in industrial circuit simulation

AbstractIn this paper the industrial application of Reduced Order Multirate (ROMR) schemes is presented. This paper contains the mathematical foundations of the ROMR schemes and elaborates on the construction of these schemes using specific Model Order Reduction (MOR) techniques. Especially the Maximum Entropy Snapshot Sampling method for generating a reduced basis and reduction by Gauß–Newton with Approximated Tensors (GNAT). This basis generation method is also used for generating the basis for the gappy hyper-reduction method used for nonlinear function evaluation. For the multirate integration part, a Backward Differentation Formula approach to integration is used in conjunction with a coupled-slowest-first multirate approach. After introducing the numerical approach to industrial circuit simulation validation experiments are performed. First a simple academic model is used, and then an industrial test case is simulated as presented by STMicroelectronics. A significant speedup in simulation time is achieved whilst accuracy and convergence is kept

Synthesis of Interleaved, Unipolar, Switched Capacitor DC-DC Converters

Switched Capacitor (SC) DC-DC converters are showing great potential for new applications such as data-centres, electric vehicles and power transmission. Many SC topologies have been synthesised on an ad-hoc basis, although new computer methods are being introduced to formalise this process. This paper presents a general synthesis technique that can be incorporated into a computer algorithm to assist with the development of new SC circuits. The technique is based on interleaving SC converter circuits, where two unipolar converters are connected in parallel, and each leg is driven by separate, complementary gate signals. By applying this method to the traditional Ladder SC converter, a topology termed as a Simplified Interleaved Ladder (SIL) converter, is synthesised and tested using a hardware prototype. The resonant implementation of the SIL converter has desirable features for MV/LV applications when compared with other existing SC circuits

Speed control of induction machine based on direct torque control method

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de ComputadoresMulti-level converters have been receiving attention in the recent years and have been proposed as the best choice in a wide variety of medium voltage applications. They enable a commutation at substantially reduced voltages and an improved harmonic spectrum without a series connection of devices, which is the main advantage of a multi-level structure. The use of multi-level inverters contributes to the performances amelioration of the induction machine control. In fact, the use of three level inverter (or multilevel inverter) associated with DTC control can contribute to more reducing harmonics and the ripple torque and to have a high level of output voltage. A variation of DTC-SVM with a three level neutral point clamped inverter is proposed and discussed in the literature. The goal of this project is to study, evaluate and compare the DTC and the proposed DTC-SVM technique when applied to induction machines through simulations. The simulations were carried out using MATLAB/ SIMULINK simulation package. Evaluation was made based on the drive performance, which includes dynamic torque and flux responses, feasibility and the complexity of the systems

Measurements, Models, Systems and Design

531 s.