http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

The aim of this paper is to present a review of current control techniques for three-phase voltage-source pulsewidth modulated converters. Various techniques, different in concept, have been described in two main groups: linear and nonlinear. The first includes proportional integral (stationary and synchronous) and state feedback controllers, and predictive techniques with constant switching frequency. The second comprises bang-bang (hysteresis, delta modulation) controllers and predictive controllers with on-line optimization. New trends in current control-neural networks and fuzzy-logic-based controllers-are discussed, as well. Selected oscillograms accompany the presentation in order to illustrate properties of the described controller groups.

Current control techniques for three-phase voltage-source PWM converters: a survey

This paper addresses to some of the latest contributions on the application of Finite Control Set Model Predictive Control (FCS-MPC) in Power Electronics. In FCS-MPC , the switching states are directly applied to the power converter, without the need of an additional modulation stage. The paper shows how the use of FCS-MPC provides a simple and efficient computational realization for different control objectives in Power Electronics. Some applications of this technology in drives, active filters, power conditioning, distributed generation and renewable energy are covered. Finally, attention is paid to the discussion of new trends in this technology and to the identification of open questions and future research topics.

State of the Art of Finite Control Set Model Predictive Control in Power Electronics

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 gives an overview of medium-voltage (MV) multilevel converters with a focus on achieving minimum harmonic distortion and high efficiency at low switching frequency operation. Increasing the power rating by minimizing switching frequency while still maintaining reasonable power quality is an important requirement and a persistent challenge for the industry. Existing solutions are discussed and analyzed based on their topologies, limitations, and control techniques. As a preferred option for future research and application, an inverter configuration based on three-level building blocks to generate five-level voltage waveforms is suggested. This paper shows that such an inverter may be operated at a very low switching frequency to achieve minimum on-state and dynamic device losses for highly efficient MV drive applications while maintaining low harmonic distortion.

Medium-Voltage Multilevel Converters—State of the Art, Challenges, and Requirements in Industrial Applications

This paper compares the Cascaded H-Bridge (CHB) converter topology with the Modular Multilevel Converter topology (M2LC) for the use in battery energy storage systems (BESS). Standard modules are examined as well as extended modules allowing an increase in output voltage. Semiconductor and capacitor requirements are evaluated by simulation, and practical considerations are discussed. Experimental results from a laboratory setup of a CHB based BESS are presented.

Comparison of Cascaded H-Bridge and Modular Multilevel Converters for BESS application

This paper deals with a method to derive the junction temperature of an IGBT while the device is in operation. In order to achieve this the gate-emitter voltage, the collector current and the collector-emitter voltage are digitized on the driver board. Due to the fact that material parameters vary with temperature, the waveforms of the switching transients vary with temperature, too. Thus, there is a correlation between the temperature and the switching waveforms. Evaluating temperature sensitive electrical parameters (TSEP), the working temperature of the device can be estimated.

On-line junction temperature measurement of IGBTs based on temperature sensitive electrical parameters

Silicon carbide (SiC) based power semiconductors are expected to contribute to an increase in inverter efficiency, switching frequencies, maximum permissible junction temperature, and system power density. This paper presents a comparison of silicon (Si) and SiC device technologies for the use in hybrid electric vehicle traction inverters. SiC-JFETs and SiC-MOSFETs are characterized and a scalable loss and scalable thermal modeling approach is used to find the optimum chip area for each Si or SiC traction inverter. This procedure also provides a proper technical comparison of the semiconductor technologies. The progressed simulations using standardized drive cycles and thermal-electrical coupled semiconductor models permit an inverter performance evaluation close to real load situations, leading to an improved estimation of the benefit which can be expected from systems utilizing SiC technology. This paper concludes that the SiC devices can lead to a reduction in chip area and semiconductor losses by more than 50% at the same time in hard switching applications with partial load dominated mission profiles.

Characterization and Scalable Modeling of Power Semiconductors for Optimized Design of Traction Inverters with Si- and SiC-Devices

A new ac/ac modular multilevel topology for connecting two three-phase systems is introduced. The operating principle is explained, and characteristic waveforms are given. It is shown that the converter system offers superior performance for applications like low-frequency wind turbines. The analytic results are verified by a laboratory setup.

A New Three-Phase AC/AC Modular Multilevel Converter With Six Branches in Hexagonal Configuration

This paper presents a generalized control concept that can be applied to a class of modular multilevel converter topologies. Examples for such topologies are the Modular Multilevel Converter, the Modular Multilevel Matrix Converter, and the Hexverter. The presented control approach consists of a current control based on the state-space representation and a branch energy balancing control. For the branch energy balancing, an optimization process leading to minimal additional current stress is presented. After describing the control approach in general form, it is applied exemplarily to the Modular Multilevel Matrix Converter. A comparison with the branch energy balancing for the Modular Multilevel Matrix Converter from previous publications is conducted, which shows the improvement achieved by the presented control. In fact, the previously published controllers are boundary cases of the presented optimized solution. The generalized control concept is verified by simulation and experimental results for the Modular Multilevel Matrix Converter. It can be easily applied to new configurations.

Axel Mertens

Papers

Comparison of Cascaded H-Bridge and Modular Multilevel Converters for BESS application

On-line junction temperature measurement of IGBTs based on temperature sensitive electrical parameters

Characterization and Scalable Modeling of Power Semiconductors for Optimized Design of Traction Inverters with Si- and SiC-Devices

A New Three-Phase AC/AC Modular Multilevel Converter With Six Branches in Hexagonal Configuration

Generalized Control Approach for a Class of Modular Multilevel Converter Topologies