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

Power electronics

The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters and generalized to any number of switches.<<ETX>>

Multi-level conversion : high voltage choppers and voltage-source inverters

The main objective of this two-part state-of-the-art paper called “Recent Advances in the Design, Modeling, and Control of Multiphase Machines” is to present latest contributions in the multiphase machines' field. The first part of this paper focuses on the recent progress in the design, modeling, and control, whereas the drive is in healthy operation. This second part presents relevant contributions in two not analyzed fields. The first is in relation with the use of the additional degrees of freedom of multiphase machines and the exploitation of their fault-tolerant capabilities without adding extra hardware. The second one analyzes multiphase generation, particularly in grid-connected wind energy conversion systems and stand-alone applications. Recent progresses are shown and open challenges and future research directions are discussed.

Recent Advances in the Design, Modeling, and Control of Multiphase Machines—Part II

Doubly fed induction generators (DFIGs), often organized in wind parks, are the most important generators used for variable-speed wind energy generation. This paper reviews the control systems for the operation of DFIGs and brushless DFIGs in wind energy applications. Control systems for stand-alone operation, connection to balanced or unbalanced grids, sensorless control, and frequency support from DFIGs and low-voltage ride-through issues are discussed.

Overview of Control Systems for the Operation of DFIGs in Wind Energy Applications

A sparse auto-encoder-based deep neural network approach for induction motor faults classification

Multilevel inverters allow to generate AC voltages with low total harmonic distortion (THD) but requires an increased number of power switches. One of the disadvantages of that is the increased probability of a fault in one of the power switches. Thus in order to improve the reliability of the converter a fast and robust fault detection scheme must be used. In this context this paper presents a new fault detection scheme based on the AC voltages of the inverter. The proposed scheme uses fault factors that are based on the statistic moment method. This method was used for the identification of image patterns. Due to this the proposed scheme allows for a robust detection to load or voltage variations. To test the method was used a cascaded H-bridge inverter with five levels. Several tests were performed through numerical results. The use of a laboratory prototype was also used to confirm the proposed scheme.

Cascaded H-bridge multilevel inverter with a fault detection scheme based on the statistic moments indexes

DC-DC Buck-Boost power converters are extensively used in several applications, from renewable energy sources to most industrial equipment. Nevertheless, to achieve proper integration of certain devices it is often necessary to provide converters with extended output voltage. This paper presents a new DC-DC power converter topology with Buck- Boost operation and extended output voltage using a single power semiconductor. Additionally, this converter operates with reduced voltage stress in the power semiconductor. The performance of this power converter will be proven trough simulations and experimental tests.

A Single-Switch DC/DC Buck-Boost Converter with Extended Output Voltage

A new hybrid multilevel inverter using a single DC source for open-end winding induction motor is proposed. This power converter uses one three phase bridge inverter and three single-phase inverters, while using only one DC source. Due to the topology and voltage values, this power converter works as three single-phase multilevel inverters. In order to maximize the inverter output voltage levels there is an asymmetry between the amplitude of the three phase bridge inverter DC source and the single-phase inverter capacitor voltages. To control the three-phase inverter a SPWM modulator is used. Since the three single-phase inverters do not have DC sources an algorithm is required to maintain the capacitor voltage balanced. In this work a sliding mode control based approach is used to control the capacitor voltage of the single-phase inverters. In order to verify the proposed topology and proposed system converter several simulation results are presented.

Hybrid cascade multilevel inverter using a single DC source for open-end winding induction motors

In this paper a detection and fault diagnosis for a Voltage Source Inverter is presented The need to insure a continuous and safety operation for voltage source inverter involves the need for reliable fault diagnosis techniques The proposed approach uses an automatic three step algorithm Firstly, the inverter output currents are measured which will give typical patterns that can be used to identify the fault Secondly, the Eigenvectors/Eigenvalues of the 3D current referential are computed Finally the proposed algorithm will discern if there is any fault and report the faulty switch The proposed approach was experimentally implemented and its performance verified on various types of working conditions

An Eigenvalue/Eigenvector 3D current reference method for detection and fault diagnosis in a voltage source inverter

The ongoing increase of PhotoVoltaic (PV) microgeneration, pointing to high levels of penetration, can lead to the occurrence of overvoltages. Moreover, the inherent unbalanced nature of the LV distribution grid is a difficulty that must be considered when designing countermeasures. On the other hand, storage systems are suitable devices that can help the process of voltage control. This paper proposes a control system for a real-time energy management system, using Multi-Objective Particle Swarm Optimization (MOPSO) on a highly unbalanced LV distribution network, with batteries and a high share of PV. The purpose of the control system is the optimization of four objectives: Voltage Unbalance Factor (VUF), voltage deviation, active power losses and PV curtailment, wherein four scenarios were considered for assessment. This study is conducted using an unbalanced three-phase power flow algorithm. A comparison of residential and community storage is performed. The results show that the inclusion of storage devices near the prosumers’ PV systems is the recommended solution to enhance voltage stability and balance. Moreover, a significant reduction of active power losses in the LV network is observed.

V. Fernao Pires

Papers

Cascaded H-bridge multilevel inverter with a fault detection scheme based on the statistic moments indexes

A Single-Switch DC/DC Buck-Boost Converter with Extended Output Voltage

Hybrid cascade multilevel inverter using a single DC source for open-end winding induction motors

An Eigenvalue/Eigenvector 3D current reference method for detection and fault diagnosis in a voltage source inverter

Energy management in unbalanced low voltage distribution networks with microgeneration and storage by using a multi-objective optimization algorithm