High-Performance 3-Phase 5-Level E-Type Multilevel–Multicell Converters for Microgrids

Abstract

This paper focuses on the analysis and design of two multilevel–multicell converters (MMCs), named 3-phase 5-Level E-Type Multilevel–Multicell Rectifier (3Φ5L E-Type MMR) and 3-phase 5-Level E-Type Multilevel–Multicell Inverter (3Φ5L E-Type MMI) to be used in microgrid applications. The proposed 3-phase E-Type multilevel rectifier and inverter have each phase being accomplished by the combination of two I-Type topologies connected to the T-Type topology. The two cells of each phase of the rectifier and inverter are connected in interleaving using an intercell transformer (ICT) in order to reduce the volume of the output filter. Such an E-Type topology arrangement is expected to allow both the high efficiency and power density required for microgrid applications, as well as being capable of providing good performance in terms of quality of the voltage and current waveforms. The proposed hardware design and control interface are supported by the simulation results performed in Matlab/Simulink. The analysis has been then validated in terms of an experimental campaign performed on the converter prototype, which presented a power density of 8.4 kW/dm3 and a specific power of 3.24 kW/kg. The experimental results showed that the proposed converter can achieve a peak efficiency of 99% using only silicon power semiconductors.

Recovery of Trains’ Braking Energy in a Railway Micro-Grid Devoted to Train plus Electric Vehicle Integrated Mobility

“…In addition to Equation (7), the electrical power at the inverter input terminals is considered in order to determine the current in the DC link of the overall traction drive. To this goal, the overall power loss in the power electronic conversion system is determined by using the approach earlier proposed in [37] and already used in [38]. Hence, both the switching power loss and the conduction power loss in the inverter switches and diodes are evaluated by considering only the fundamental harmonic of the inverter output phase current that is being represented by the time function:…”

Analysis and Design of a High-Efficiency SiC MOSFET 6-Phase Boost Rectifier

“…In a two-level converter, the maximum blocking voltage is equal to the DC-bus voltage V BUS . The overvoltage ∆V, instead, depends on many factors, such as the leak inductance L S , the current transient di/dt, the coefficient k R to consider possible resonance in the DC-bus circuit, and the voltage drop across the free-wheeling diode V FR [22,23]. Therefore, the voltage rating can be estimated as in (1).…”

“…Considering a sinusoidal pulse width modulation (SPWM), the duty cycle waveform can be found as in (5), where the subscript "p" stands for the top switches, whereas the subscript "n" represents the bottom switches, and M is the modulation depth [23].…”

Switching Frequency Effects on the Efficiency and Harmonic Distortion in a Three-Phase Five-Level CHBMI Prototype with Multicarrier PWM Schemes: Experimental Analysis

“…In this context, Multilevel Power Inverters (MPIs) are a promising solution since they present, with respect to the traditional three-phase two-level inverters, reduced harmonic content in the output voltages, lower voltage stress in the power components, and reduced Electromagnetic Interference (EMI) [6,7]. Therefore, multilevel power inverters, because of these features, represent a valid solution in many fields of application where high performance is required [8][9][10].…”