Model predictive control (MPC) is a very attractive solution for controlling power electronic converters. The aim of this paper is to present and discuss the latest developments in MPC for power converters and drives, describing the current state of this control strategy and analyzing the new trends and challenges it presents when applied to power electronic systems. The paper revisits the operating principle of MPC and identifies three key elements in the MPC strategies, namely the prediction model, the cost function, and the optimization algorithm. This paper summarizes the most recent research concerning these elements, providing details about the different solutions proposed by the academic and industrial communities.

/pdf/model-predictive-control-for-power-converters-and-drives-1x9taym0xu.pdf

Model Predictive Control for Power Converters and Drives: Advances and Trends

This paper presents a review of the most popular control and modulation strategies studied for matrix converters (MCs) in the last decade. The purpose of most of these methods is to generate sinusoidal current on the input and output sides. These methods are compared considering theoretical complexity and performance. This paper concludes that the control strategy has a significant impact on the resonance of the MC input filter.

A Review of Control and Modulation Methods for Matrix Converters

This paper presents first an overview of the well-known voltage and current dc-link converter topologies used to implement a three-phase PWM ac-ac converter system. Starting from the voltage source inverter and the current source rectifier, the basics of space vector modulation are summarized. Based on that, the topology of the indirect matrix converter (IMC) and its modulation are gradually developed from a voltage dc-link back-to-back converter by omitting the dc-link capacitor. In the next step, the topology of the conventional (direct) matrix converter (CMC) is introduced, and the relationship between the IMC and the CMCs is discussed in a figurative manner by investigating the switching states. Subsequently, three-phase ac-ac buck-type chopper circuits are considered as a special case of matrix converters (MCs), and a summary of extended MC topologies is provided, including three-level and hybrid MCs. Therewith, a common knowledge basis of the individual converter topologies is established.

Review of Three-Phase PWM AC–AC Converter Topologies

Silicon carbide (SiC) switching power devices (MOSFETs, JFETs) of 1200 V rating are now commercially available, and in conjunction with SiC diodes, they offer substantially reduced switching losses relative to silicon (Si) insulated gate bipolar transistors (IGBTs) paired with fast-recovery diodes. Low-voltage industrial variable-speed drives are a key application for 1200 V devices, and there is great interest in the replacement of the Si IGBTs and diodes that presently dominate in this application with SiC-based devices. However, much of the performance benefit of SiC-based devices is due to their increased switching speeds ( di/dt, dv/ dt), which raises the issues of increased electromagnetic interference (EMI) generation and detrimental effects on the reliability of inverter-fed electrical machines. In this paper, the tradeoff between switching losses and the high-frequency spectral amplitude of the device switching waveforms is quantified experimentally for all-Si, Si-SiC, and all-SiC device combinations. While exploiting the full switching-speed capability of SiC-based devices results in significantly increased EMI generation, the all-SiC combination provides a 70% reduction in switching losses relative to all-Si when operated at comparable dv/dt. It is also shown that the loss-EMI tradeoff obtained with the Si-SiC device combination can be significantly improved by driving the IGBT with a modified gate voltage profile.

An Experimental Investigation of the Tradeoff between Switching Losses and EMI Generation With Hard-Switched All-Si, Si-SiC, and All-SiC Device Combinations

This paper introduces the methodology and the results of a comprehensive comparison of a direct matrix converter (MC), an indirect MC, and a voltage dc-link back-to-back converter for a 15-kW permanent magnet synchronous motor drive. The comparison involves the investigation of the passive components, including the EMI input filter, the required silicon chip area for a defined maximum admissible thermal loading of the power semiconductors, the total losses and/or achievable efficiency, a prediction of the resulting volume and weight of the passive components, and, finally, a tradeoff study between the efficiency, volume, and weight of the converters. Different performance indicators that ultimately allow a systematic determination of the application area of each converter topology are provided with this comparative evaluation.

Comparative Evaluation of Three-Phase AC–AC Matrix Converter and Voltage DC-Link Back-to-Back Converter Systems

This paper deals with the design, control, and implementation of a three-phase ground power-supply unit for aircraft servicing. Instead of a classical back-to-back converter configuration, a three-phase direct ac-ac (matrix) converter has been used as the power conditioning core of the power supply, working in conjunction with input and output LC filters. An optimized control system in the ABC frame employing a repetitive controller has been successfully implemented, taking into account both the transient and steady-state performance targets together with the system effectiveness under extreme unbalanced conditions. Extensive experimental tests on a 7.5-kVA prototype prove the efficiency of the designed system in meeting the high demanding civil and military international standards requirements.

Control and Implementation of a Matrix-Converter-Based AC Ground Power-Supply Unit for Aircraft Servicing

The interest in using the matrix converter (MC) for motor drive applications and energy conversion systems is steadily increasing due to its main advantage of performing a direct coupling between two three-phase alternating current sources without the need of an intermediate direct current bus. This characteristic, together with the presence of inductance-capacitance input filters and the feedforward compensation of the input voltage variations, might yield unstable operation in electrical drives. In this paper, a theoretical analysis of MCs based on a large-signal model is presented with the aim to show which parameters may affect the stability and to explain the reason of this phenomenon. The theoretical analysis is supported by several experimental tests carried out on an MC prototype

Large-Signal Model for the Stability Analysis of Matrix Converters

This paper presents a new speed finite control set model predictive control algorithm, which has been applied to a permanent-magnet synchronous motor driven by a matrix converter (MC) This method replaces the classical cascaded control scheme with a single control law that controls the motor currents and speed Additionally, unlike classical MC modulation methods, the method allows direct control of the MC input currents The performance of the proposed work has been verified by simulation studies and experimental results

/pdf/speed-finite-control-set-model-predictive-control-of-a-pmsm-3bt0jcrfxv.pdf

Speed Finite Control Set Model Predictive Control of a PMSM Fed by Matrix Converter

Matrix converters perform a direct coupling between two ac sources without the need for energy storage components. This characteristic, together with the presence of L-C input filters and the feedforward compensation of the input voltage variations, may determine unstable operation as the power delivered to the load exceeds a limit value. In this paper, a theoretical analysis of the stability of matrix converters is presented with the aim of predicting possible critical operating conditions. It is verified that all of the system parameters affect more or less the stability, including the delay introduced by the digital controller and the power losses. The theoretical analysis is supported by numerical simulations and experimental results carried out on a matrix converter prototype.

Theoretical and experimental investigation on the stability of matrix converters

This article introduces the more electric aircraft concept and investigate the potential benefits of the technology for manned aircraft. Typical aircraft electrical power systems and loads are described as well as the exciting, future challenges for the aerospace industry. The importance of power electronics as an enabling technology for this step change in aircraft design are considered and examples of typical system designs are discussed.

Andrew Trentin

Papers

Control and Implementation of a Matrix-Converter-Based AC Ground Power-Supply Unit for Aircraft Servicing

Large-Signal Model for the Stability Analysis of Matrix Converters

Speed Finite Control Set Model Predictive Control of a PMSM Fed by Matrix Converter

Theoretical and experimental investigation on the stability of matrix converters

An overview of the more electrical aircraft