José Eduardo Baggio

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.

Isolated interleaved-phase-shift-PWM DC-DC ZVS converters

This paper describes the operation principles of an isolated ZVS DC-DC converter, which is composed by two half-bridge converters. Soft-switching is achieved for a wide load range. This ZVS DC-DC converter operates at constant frequency and it is phase-shift modulated. The main advantage of the phase-shift interleaving is the equalization of the input capacitor voltage, where each capacitor shares one-quarter of the total input voltage. The converter can be an alternative for ZVS phase-shift full-bridge DC-DC converter for high voltage applications, as result of the series arrangement in one of the two half-bridge converters. Analysis, operating principle and design procedures are presented in the paper. Experimental results from a 1.5 kW prototype converter operating at 100 kHz with isolated 60 V/25 A output are presented to validate the theoretical analysis.

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 comparative design of an optmized boost inductor taking into account three magnetic materials technologies: Volume, cost and efficiency analysis

Reducing the volume with maximum efficiency, on equipment and systems, result in a high cost, making the optimized design a great challenge for engineers. On power factor correctors (PFCs) converters, magnetic elements as inductors and transformers have a strong influence on cost, volume, power density and performance, they become the more important elements in these systems. Thus, the need for an optimized design of these components is extremely important. With this purpose, this paper presents the inductor design for a 1kW, VIN 220VAC e VOUT 400VDC, PFC boost converter. The design is developed using different operating points (Δi @ fs) and different magnetic materials technologies (Molipermalloy, High Flux and KoolMμ) to perform a comparative analysis. These powder materials have extremely attractive characteristics for PFCs and this paper indicates which material offers the best cost / benefit relationship between the three technologies of magnetic materials aforementioned.

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.

A simple active auxiliary commutation circuit for three-level PWM single-phase inverters

This paper presents the analysis and design of a new low-loss auxiliary circuit for three-level pulsewidth-modulation single-phase full-bridge inverters which achieve soft switching at all semiconductor devices. The active auxiliary commutation circuit (AACC) is composed of an LC circuit and two bidirectional switches, where one auxiliary switch commutates under zero-voltage switching condition and the other under zero-current switching condition. The AACC dispenses with the use of auxiliary voltage sources. Low reactive energy is added to the converter, resulting in low RMS current stresses at the main switches and, consequently, higher efficiency is achieved. Auxiliary circuit design procedures and experimental results are presented to prove the operation principle.

Integrated methodology design to improve the efficiency and reduce volume of the CCM PFC boost converters with pre-sizing settings

This paper presents an optimization design methodology for CCM PFC Boost converters with volume and efficiency objectives. The optimization methodology, achieved by mathematical interactions, is based on the concept of the converter integrated design, in other words, all the main physical converter components are designed simultaneously in the function of a pair of overall variables. The integrated design provides for the reduction of cost and time of the project design of the system and also gives complete and matched solutions with the objective of the proposed optimization. The proposed methodology is evaluated with a PFC Boost converter including an input EMI filter (1000-W output power, 400-VDC output voltage and 220-VAC input voltage). In this case study, three different magnetic materials are used in both inductors designs (Boost and EMI filter) in order to demonstrate how technology affects the volume and efficiency results. To confirm the theoretical analysis that was carried out, the experimental mechanical, electrical and thermal measurements are presented.

CubeSat electrical power supplies optimization — Comparison between conventional and optimal design methodology

Satellites and space application devices demands high efficiency with size, volume, mass and losses reduced simultaneously due to low power generation in space orbit and the relation between mass and the overall space mission cost. To minimize costs and promote high acess to universities, small companies and institutes a nanosatellite was developed in early 2000, the CubeSat class. Therefore the need to save energy is mandatory in all systems due to low power generation and reduced size. This work focuses in the electrical power supply (EPS), system responsible to generate, store, conditioning and supply electrical power for the whole satellite. Thus is presented a comparison between a conventional power converter design and an optimization design methodology for boost power converters in order to improve efficiency, to reduce volume and mass for 1U CubeSat EPS. Results have shown the method effectiveness and efficiency maximization was achieved respecting the 1U CubeSat constraints.