Leandro Roggia

Integrated Full-Bridge-Forward DC–DC Converter for a Residential Microgrid Application

This paper proposes a novel integrated converter topology for interfacing between the energy storage system and the dc bus for a residential microgrid application. The proposed integrated full-bridge-forward dc–dc converter presents the following features: low number of active devices compared to the converters usually applied to similar applications, low input and output current ripple, high voltage ratio, bidirectional power flow, and galvanic isolation. A double-ended forward converter with particularities such as no extra transformer demagnetizing circuit is originated from the integration process. This converter is approached in detail in this paper, including three different clamping circuits which are analyzed and compared. The structure, principle of operation, analysis, transformer design methodology, comparison with the dual active bridge converter, and experimental results of the proposed topology are presented.

Digital control system applied to a PFC boost converter operating in mixed conduction mode

This paper proposes a digital control system applied to a power factor correction boost converter rated to a wide range of output power, operating in mixed conduction mode with fixed switching frequency. The control system is composed of an input current controller and an output voltage controller. The current controller comprises two predictive model-based control laws (one for the continuous conduction mode and another for the discontinuous conduction mode) and an operation mode selection algorithm, which is responsible for detecting the operation mode and selecting the appropriate control law. The output voltage is regulated using a proportional-integral voltage controller. Simulation and experimental results applying a low cost microcontroller are shown to ensure the operation of the proposed control system.

A comparison of high power single-phase power factor correction pre-regulators

In this paper, a comparison of three high power single-phase power factor correction (PFC) pre-regulators is proposed. The topologies discussed are the boost converter, the interleaved boost converter and the dual boost converter. The control system used to perform the PFC is based in predictive current control laws and an algorithm to detect the conduction modes is also used, once the converters operate in mixed conduction mode. All topologies have the same input current, input voltage, output voltage, load and controller. Furthermore, all topologies have the same rms current and total harmonic distortion (THD) values of the input current, and, therefore, equal input filters. The comparison parameters are: input power factor, conducted electromagnetic interference (EMI), core losses, power losses, heat-sink volume, total volume, efficiency and number of components and devices. Theoretical and experimental results are presented to analyze the comparisons between the converters.

Comparison among digital current controllers applied to power factor correction boost converters

This paper proposes two digital predictive current controllers applied to power factor correction boost converters. A comparison among these two controllers and another one already presented in the literature is also made. These controllers have in common the possibility of operation in the discontinuous, mixed and continuous conduction modes. The control systems goal is to provide a high power factor and a low total harmonic distortion to the input current of the converter. The control laws and the structure of the proposed controllers are shown in details. Simulation and experimental results, together with waveforms quality indexes, are also shown, in order to analyze and compare the performance of the controllers.

Implementation issues of a digital control system applied to a PFC boost converter

This paper presents implementation issues of a digital control system applied to a power factor correction (PFC) boost converter rated to a wide range of output power, operating in mixed conduction mode (MCM). The digital control system comprises an input current controller and an output voltage controller. The current controller is formed by two predictive model-based control laws, while the output voltage is regulated through a proportional-integral controller. The implementation requirements of this control system and the executed programming routines, highlighting the inductor current sampling process in different conduction modes are discussed. Experimental results applying a low cost microcontroller are shown to validate the operation of the current and voltage controllers.

EMI investigation yield by single-phase PFC pre-regulators

This paper investigates the problem of electromagnetic interference (EMI) generated into power converters used to correct the power factor (PFC). The topologies discussed in this paper are the boost converter, interleaved boost and dual boost. The paths traveled by differential mode (DM) noise and common mode (CM) noise are illustrated. An analysis of the inductor parasitic capacitance impact over the conducted noise is realized. All converters were designed in a way that the total harmonic distortion (THD) of the input current be the same, in order to use the same input filter. The EMI filter designed to comply with the EMI standards and experimental results with filter are also shown.

Comparison between full-bridge-forward converter and DAB converter

This paper analyzes and compares the dual active bridge (DAB) converter and the full-bridge-forward integrated DC-DC converter when applied to a microgrid energy storage bidirectional system that demands high power flow at the discharging operation mode and low power flow at the charging operation mode. The phase-shift modulation (PSM) is generally applied on the DAB converter, but it presents practical limitations, such as maximum and minimum phase-shift angle restrictions. In order to obtain a wide power variation range on the discharging operation mode, a hybrid modulation scheme can be applied. On the other hand, the full-bridge-forward DC-DC converter is also an alternative, which is specifically designed for different power level bidirectional processes and therefore presents low number of active devices. Theoretical analysis and experimental results of both converters are presented.

DAB Converter Modeling and Control Applied to Charging Batteries

Photovoltaic systems are assuming an important role in the integration of renewable sources in the energy generation. The number of connections of this type of generation has grown considerably in recent years, bringing with it problems such as varying voltage, current, power and frequency levels at points with a large number of connections. Therefore, in order to maintain these levels within acceptable ranges and since it is a source that has an intermittent characteristic, it is necessary to integrate a system of energy storage (batteries, for example) for the best use of the generated energy. For the connection of the generation system to the battery bank it becomes necessary to use a DC-DC converter with high voltage gain, bidirectionality in the power flow and galvanic isolation. In this work, the Dual Active Bridge (DAB) converter with topological modification in the output is used, and the mathematical modeling of the converter is performed through two methods: the generalized average model and the linearization of the output current. In addition, a comparative analysis between the methods is performed and the Artigo submetido em 27/11/2017. Primeira revisão em 13/02/2018. Aceito para publicação em 17/04/2018 por recomendação do Editor Marcello Mezaroba. design of a current controller for the DAB is developed. Finally, the experimental results are presented. 

Circulating current mitigation in Dual Active Bridge converter

This work brings forward a new methodology to maximize the efficiency of Dual Active Bridge (DAB) converter for its several patterns of operation. This goal is reached by the mitigation of its processed circulating energy. It is proposed a figure of merit which relates the average input current and the RMS current of the power transfer inductor, and an algorithm to select the trio of control variables (D1, D2, φ) ensuring that this objective is achieved. It has been performed a detailed steady-state analysis of every pattern for all the possible modulations, as well as the identification of all commutations under zero voltage of the Full-Bridges that compose the DAB. Due to the twelve different modulation patterns presented by the DAB that affect directly the operation mode, the design, the volume, the weight, and different performances can be achieved. In this way, it is verified the impact of the control variables on converter efficiency, as well its relationships with the average input current and the RMS inductor current. Results show that the converter efficiency obtained for different operation points making the use of the developed algorithm are very close to those obtained making the computation by the optimal converter efficiency.

EMI conduzida gerada por conversores estáticos aplicados à correção do fator de potência

This paper investigates the conducted electromagnetic interference (EMI) yielded by power converters used power factor correction.The topologies discussed in this paper are the boost, interleaved boost and dual boost converters. An analysis of the conducted noise behavior of differential mode and common mode in the converters are presented. All converters are designed in a way that the total harmonic distortion of the input current are same, in order to use the same input filter. It is presented the EMI filter design in order to adapt the converters as the standard of electromagnetic interference, CISPR. Experimental results of converters operating in power factor correction for a load of 300W is presented, as well as, experimental results of EMI analyzing the impact of the use of EMI filter, the alteration of the gate resistance of the semiconductor switches and changed in the configuration of the inductor boost for dual boost topology.