Carlos Roncero-Clemente

Single phase three-level quasi-z-source inverter with a new boost modulation technique

This paper describes a new modulation technique for a single phase three-level neutral-point-clamped qZS inverter. The proposed converter is intended for applications that require input voltage gain and high quality of the output voltage. The simulation and experimental results are presented and discussed.

CCM operation analysis of the single-phase three-level quasi-Z-source inverter

This paper presents a CCM analysis of a new modification of a three-level single phase neutral-point-clamped inverter. The proposed topology combines advantages of the three-level neutral-point-clamped full-bridge inverter with those of the quasi-Z-source inverter. The three-level neutral-point-clamped quasi-Z-source inverter is especially suitable for renewable energy sources. The steady-state analysis of a three-level neutral-point-clamped quasi-Z-source inverter in the case of the continuous conduction mode is presented. The conditions of the continuous conduction mode are obtained and analyzed.

Comparison of Impedance-Source Networks for Two and Multilevel Buck–Boost Inverter Applications

Impedance-source networks are an increasingly popular solution in power converter applications, especially in single-stage buck-boost power conversion to avoid additional front-end dc-dc power converters. In the survey papers published, no analytical comparisons of different topologies have been described, which makes it difficult to choose the best option. Thus, the aim of this paper is to present a comprehensive analytical comparison of the impedance-source-based buck-boost inverters in terms of passive component count and semiconductor stress. Based on the waveform of the input current, i.e., with or without a transformer, and with or without inductor coupling, the impedance-source converters are classified. The main criterion in our comprehensive comparison is the energy stored in the passive elements, which is considered both under constant and predefined high frequency current ripple in the inductors and the voltage ripple across the capacitors. Two-level and multilevel solutions are described. The conclusions provide a “one-stop” information source and a selection guide of impedance-source-based buck-boost inverters for different applications.

Experimental Investigation of high frequency 3L-NPC qZS inverter for photovoltaic application

This paper presents an experimental investigation of a single phase three-level neutral-point-clamped quasi-Z-source inverter for photovoltaic application. The prototype and the case study system are described. Experimental results along with theoretical losses analysis are discussed. The implemented maximum power point tracking algorithm was verified in a real photovoltaic system.

Comparison of two power flow control strategies for photovoltaic inverters

High penetration levels of distributed photovoltaic inverters on electrical distribution grids and due to the main points demanded in the latest issues of grid codes such as the reactive power injection during transient grid faults (voltage sags) and their disconnection in order to avoid the islanding phenomena, a suitable control algorithm combination is needed to provide an optimum operation at the electrical grids where they are connected, improving the power quality and the power supply continuity. This paper is devoted to the comparison through simulation of two power flow control strategies for 100 kW photovoltaic inverters in order to analyze the advantages and disadvantages of each one. The first one is based on the modulation index and the disphase controls of the reference signal face to the point of common coupling voltage. The second one is based on a synchronous reference frame with the voltage at the point of common coupling using id and iq current component controllers.

Voltage Distortion Approach for Output Filter Design for Off-Grid and Grid-Connected PWM Inverters

This paper proposes a novel voltage distortion approach for output filter design based on the voltage transfer function for both off-grid and grid-connected Pulse Width Modulation (PWM) Inverters. The method explained in detail is compared to conventional methods. A comparative analysis is performed on an example of L and LCL-filter design. Simulation and experimental results for the off-grid and the grid-connected single phase inverter prove our theoretical predictions. It was found that conventional methods define redundant values of the output filter elements. Assumptions and limitations of the proposed approach are also discussed.

Simulation Study of Different Modulation Techniques for Three-Level Quasi-Z-Source Inverter

Abstract In this paper several modulation techniques for a three-level neutral-point-clamped quasi impedance source inverter are proposed and discussed. Mathematical descriptions with simulation results are presented for each modulation technique. Their advantages and disadvantages are shown and guidelines for further improvement are provided.

Hysteresis current control with distributed shoot‐through states for impedance source inverters

Summary This paper presents a hysteresis current control technique with shoot-through states distribution. This control algorithm could be applied to three-level and multi-level inverters with any impedance source network where reference current control signal along with shoot-through states are required. Possible modifications of the presented algorithm are discussed. The steady-state analysis was made to explain the operation principle of the algorithm. As a result, the link between the band ratio of the hysteresis current controller, the input voltage, and the desired DC-link voltage was obtained. All theoretical predictions were proved by simulation and experimental results. Future applications are discussed.Copyright

Simulation study of the grid-connected single-phase impedance-sourced NPC inverter with different control methods

Focus is on three operation strategies for a grid-connected three-level neutral-poi n t-clamped quasi impedance source inverter in a single-ph as e application. Each control scheme wa s implemented in the PS CAD/EMTDC simulation tool a n d underwent different tests, which involved some steps in the reference values and in the perturbations applied to the system. A comparison according to their responses was based on different criteria, such as rise time, settle time, overshoot a n d steady state error, in order to determine which would be more suitable for such application.

Three-Level Neutral-Point-Clamped Quasi-Z-Source Inverter with Maximum Power Point Tracking for Photovoltaic Systems

This article is focused on a photovoltaic system based on the three-level neutral-point-clamped quasi-z-source inverter. The maximum power point tracking (MPPT) algorithm based on dP/dV feedback was used in the photovoltaic system to adjust the duration of the shoot-through states of power switches and achieve a maximum power. Proper system operation in the case of irradiance step is demonstrated by simulation in Matlab/Simulink software.