Predictive control in matrix converters. Part I, Principles, topologies and applications

This paper presents an overview of the predictive control principles applied to matrix converters and also the different topologies where this control technique is applied. It will be shown that the predictive strategy is a promising alternative to control matrix converters due to its simplicity and flexibility to include additional aspects in the control being suitable for different industrial applications

Modelling, simulation and real time implementation of a three phase AC to AC matrix converter

Matrix converters (MCs) are essentially forced commutated cycloconverters with inherent four quadrant operation consisting of a matrix of bidirectional switches such that there is a switch for each possible connection between the input and output lines. Matrix converter directly converts the AC input voltage at any given frequency to AC output voltage with arbitrary amplitude at any unrestricted frequency without the need for a dc link capacitor storage element at the input side.The introduction of bidirectional switches using power transistors and IGBTs made easy realization of the matrix converter. The real development of the matrix converter starts with the work of Venturini and Alesina who proposed a mathematical analysis and introduced the Low-Frequency Modulation Matrix concept to describe the low frequency behavior of the matrix converter [1-3]. In this, the output voltages are obtained by multiplication of the modulation matrix or transfer matrix with the input voltages. One of the essential requirements for switching three phase AC to three phase AC MC is that two or more bidirectional switches connected to any one output phase should NOT be closed simultaneously, as this will cause dangerously high short circuit current. Similarly any one bidirectional switch connected to each output phase should remain closed to provide a current path with inductive load.This thesis mainly provides an account of the three phase AC to three phase AC MC modelling concept with SIMULINK software using fundamental Venturini and Optimum Venturini modulation algorithm [1-8], advanced modulation algorithm such as that proposed by Sunter-Clare [11-12] and by Ned Mohan [13-14, 16-17], application of these algorithms for the Vector control of three phase Induction Motor (IM) drive [15], real time hardware in the loop simulation [51,54-55] for a three phase AC to single phase AC MC, three phase AC to three phase AC Multilevel MC (MMC) with three [18-19] and six flying capacitors per output phase using PSCAD software (as SIMULINK started shooting trouble), Indirect (ISVM) [25-30] and Direct (DASVM, DSSVM, CZASVM) [31-38] Space Vector Modulation, newly discovered dual programmable AC to DC rectifier concept using three phase AC to three phase AC MC [43-45], Delta-Sigma Modulated MC [46-49] and single phase AC to three phase AC MC [50].In addition a novel concept of a single phase / three phase AC to single phase / three phase AC converter using a DC link, complementary N and P MOSFETs and IGBTs is presented. A chapter on model verification is also presented where selected SIMULINK models from various chapters have been verified by using either PSCAD or PSIM software. An appendix on PIC microcontroller PIC16F84A application to saw-tooth carrier waveform generation and switching three phase AC to three phase AC converters using a DC link is added. Another appendix on speed control and brake by plugging of three phase induction motor fed by matrix converter is presented. List of publications from this thesis is presented on third appendix

An indirect space-vector modulated three-phase AC-DC matrix converter for hybrid electric vehicles

This paper presents a bi-directional AC-DC matrix converter for the power supply systems of hybrid electric vehicles. Compared to conventional PWM rectifier and associated DC-DC converter, large DC bus capacitor banks are eliminated. The converter converts three-phase AC power into the desired DC output with higher energy density via a single power stage. A closed-loop control strategy based on indirect space vector modulation is proposed and the validity has been verified. The strategy ensures that the output voltage can be regulated tightly against different loads and wide input variation and high-quality input current can be achieved

A new class of hybrid AC/AC direct power converters

Variable voltage and variable frequency conversion of electrical energy from an AC source to an AC load is done in traditional power converters via a DC-link where an energy storage element (electrolytic capacitors) is situated. Despite its well-known benefits, it has the disadvantage of being bulky and to limit the converter lifetime. On the other hand, Direct Power Conversion (DPC) is an attractive concept, which doesn’t need an energy storage buffer, but has two main disadvantages: reduced voltage transfer ratio (<0.86) and low immunity to voltage supply disturbances. This paper proposes a new approach to perform the power conversion by mixing various standard topologies of well-known power converters in order to improve their performance/behavior. Simulation and experimental results prove that the hybrid structures are able to boost the output voltage capability (some above unity) and/or to fully compensate unbalanced voltage supply

A new class of hybrid AC/AC direct power converters

Variable voltage and variable frequency conversion of electrical energy from an AC source to an AC load is done in traditional power converters via a DC-link where an energy storage element (electrolytic capacitors) is situated. Despite its well-known benefits, it has the disadvantage of being bulky and to limit the converter lifetime. On the other hand, Direct Power Conversion (DPC) is an attractive concept, which doesn’t need an energy storage buffer, but has two main disadvantages: reduced voltage transfer ratio (<0.86) and low immunity to voltage supply disturbances. This paper proposes a new approach to perform the power conversion by mixing various standard topologies of well-known power converters in order to improve their performance/behavior. Simulation and experimental results prove that the hybrid structures are able to boost the output voltage capability (some above unity) and/or to fully compensate unbalanced voltage supply

New configurations of power converters for grid interconnection systems

The increased penetration of renewable energy sources and other distributed energy sources has been seen nowadays. In this scenario power converters play a crucial role by providing the interconnection of these energy sources. This paper presents new configurations of power converters for grid interconnection systems. Several topologies are analyzed which are based on isolated ac-ac matrix converters

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