Boost Matrix Converters in Clean Energy Systems

This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid.Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype

Input current shaped ac-to-dc converters

Input current shaping techniques for ac-to-dc converters were investigated. Input frequencies much higher than normal, up to 20 kHz were emphasized. Several methods of shaping the input current waveform in ac-to-dc converters were reviewed. The simplest method is the LC filter following the rectifier. The next simplest method is the resistor emulation approach in which the inductor size is determined by the converter switching frequency and not by the line input frequency. Other methods require complicated switch drive algorithms to construct the input current waveshape. For a high-frequency line input, on the order of 20 kHz, the simple LC cannot be discarded so peremptorily, since the inductor size can be compared with that for the resistor emulation method. In fact, since a dc regulator will normally be required after the filter anyway, the total component count is almost the same as for the resistor emulation method, in which the filter is effectively incorporated into the regulator

Three-phase ac-dc buck-boost converter with a reduced number of switches

A single-switch, single-stage, three-phase ac-dc buck-boost converter suitable for medium-voltage applications is proposed. Basic relations that govern steady-state converter operation are established, confirmed using PSCAD/EMTDC simulations, and substantiated experimentally. Simulation and experimental results establish that the proposed converter has good dynamic performance in buck and boost modes, with near unity input power factor

A Generalized Control Method for Constant Switching Frequency Three Phase PWM Boost Rectifier Under Extreme Unbalanced Operation Condition

This thesis presents a generalized control method for constant switching frequency PWM Boost Type Rectifier under extremely unbalanced operating conditions in the power system. The proposed analytical method is verified by using MATLAB/ Simulink model developed under severe unbalanced conditions of input source voltages and input impedances. The closed loop control method for controlling the output DC voltage is also presented and verified by using MATLAB/Simulink model. An experimental model is built to prove the feasibility of the proposed constant switching frequency operation of the PWM Boost Type Rectifier under extreme unbalanced operation conditions by using DSPACE RT1104 digital control syste

A Generalized Control Method for Constant Switching Frequency Three Phase PWM Boost Rectifier Under Extreme Unbalanced Operation Condition

This thesis presents a generalized control method for constant switching frequency PWM Boost Type Rectifier under extremely unbalanced operating conditions in the power system. The proposed analytical method is verified by using MATLAB/ Simulink model developed under severe unbalanced conditions of input source voltages and input impedances. The closed loop control method for controlling the output DC voltage is also presented and verified by using MATLAB/Simulink model. An experimental model is built to prove the feasibility of the proposed constant switching frequency operation of the PWM Boost Type Rectifier under extreme unbalanced operation conditions by using DSPACE RT1104 digital control syste

A Generalized Control Method for Constant Switching Frequency Three Phase PWM Boost Rectifier Under Extreme Unbalanced Operation Condition

This thesis presents a generalized control method for constant switching frequency PWM Boost Type Rectifier under extremely unbalanced operating conditions in the power system. The proposed analytical method is verified by using MATLAB/ Simulink model developed under severe unbalanced conditions of input source voltages and input impedances. The closed loop control method for controlling the output DC voltage is also presented and verified by using MATLAB/Simulink model. An experimental model is built to prove the feasibility of the proposed constant switching frequency operation of the PWM Boost Type Rectifier under extreme unbalanced operation conditions by using DSPACE RT1104 digital control syste

Power conversion for a novel AC/DC aircraft electrical distribution system

This paper proposes a novel and compact AC/DC electrical distribution system for new generation aircraft. In these new aircraft power systems, all loads are fed by two dc bus systems: at 28V and at +/-270V. The electrical distribution system, whose design and implementation are described in this paper, has only one primary AC source (360-900Hz at 230V) with all the required dc voltage levels being derived from this source. This solution enables elimination of the complex mechanical coupling apparatus currently used, for fixed frequency AC systems, to maintain the generator speed at constant level while the engines operate at variable speed. Under the proposed solution, all conversion stages needed to generate the various output voltage levels are implemented using power converters assembled in one unit. Each converter has a current control loop in order to regulate the output current even during output line short circuits and also to limit the inrush current to the circuit at turn-on. To prove the concept a 5 kW prototype was designed and tested, and demonstrated to meet all the specifications within relevant standards regarding input and output power quality

Comparative study of TEC for GISTM stations in the Peninsular Malaysia region for the period of January 2011 to December 2012

Total Electron Content (TEC) is a fundamental and the most prevalent parameter that affects Global Positioning System (GPS) signals, leading to delays, poor signals or total loss of signals. The gradients in TEC are frequently associated with disturbance in the ionosphere which explains the space weather behavior and indirectly causes inefficient operations of ground and space based Global Navigation Satellite System (GNSS) applications. The role of TEC variability is constructive in space weather prediction as it allows GNSS users to minimize rangerate errors in achieving highly reliable measurements. This paper therefore presents an analysis of the diurnal and seasonal activity dependence of TEC using data obtained from the GPS Ionospheric Scintillation and TEC Monitor (GISTM) at two stations in Peninsular Malaysia which are located at the Langkawi National Observatory, Langkawi, LGKW (06_19’N, 99_51’E) and Universiti Kebangsaan Malaysia, UKM (02_55’N, 101_46’E). Data for the two years (2011 and 2012), were recorded using the NovAtel GSV 4004B GISTM model equipment. Further investigations on a few more stations in the coast of Peninsular Malaysia will strengthen and consolidate the findings of this study

High-Voltage Stations for Electric Vehicle Fast-Charging: Trends, Standards, Charging Modes and Comparison of Unity Power-Factor Rectifiers

Emission of greenhouse gases and scarcity of fossil fuels have put the focus of the scientific community, industry and society on the electric vehicle (EV). In order to reduce CO2 emissions, cutting-edge policies and regulations are being imposed worldwide, where the use of EVs is being encouraged. In the best of scenarios reaching 245 million EVs by 2030 is expected. Extensive use of EV-s requires the installation of a wide grid of charging stations and it is very important to stablish the best charging power topology in terms of efficiency and impact in the grid. This paper presents a review of the most relevant issues in EV charging station power topologies. This review includes the impact of the battery technology, currently existing standards and proposals for power converters in the charging stations. In this review process, some disadvantages of current chargers have been identified, such as poor efficiency and power factor. To solve these limitations, five unidirectional three-phase rectifier topologies have been proposed for fast EV charging stations that enhance the current situation of chargers. Simulation results show that all the proposed topologies improve the power factor issue without penalizing efficiency. The topologies with the best overall performance are the Vienna 6-switch and the Vienna T-type rectifier. These two converters achieve high efficiency and power factor, and they allow a better distribution of losses among semiconductors, which significantly increase the life-cycle of the semiconductor devices and the reliability of the converter.This work was supported in part by the Government of the Basque Country through the Fund for Research Groups of the Basque University System under Grant IT978-16, in part by the Research Program ELKARTEK under Project ENSOL2-KK-2020/00077 and Project HARVESTGEN-KK-2020/00113, in part by the Ministerio de Ciencia e Innovacion of Spain under Project PID2020-115126RB-I00, and in part by the FEDER Funds. Documen