Search results for "converters"
showing 10 items of 140 documents
ODEF: An interactive tool for optimized design of EMI filters
2016
The impact of EMI filters on volume and weight of power converters is significant. For this reason, filter's size optimization is a strategic step towards the improvement of the power converter's power density. An EMI filter design that follows a conventional procedure does not guarantee the selection of components/configuration leading to the best power density. Therefore, in order to help EMI engineers and scientists in pursuing a fast and effective choice of optimal discrete EMI filter components and configuration, a novel tool is proposed in this paper, namely ODEF (Optimized Design of EMI Filters). ODEF is an interactive software application running in Matlab® environment. It suitably …
On the design of observers robust to load variations for synchronous converters
2015
Due to the ever growing concern on energy efficiency issues, synchronous rectification gained increasing attention in recent years. In the semiconductor industry fast controllers developed for DC-DC converters are typically based on inductor current measures. In this context system costs and performances strictly depend on the current sensor and its proper design. In this paper we present a sensorless synchronous approach based on a current observer. The same observer formulation is valid for the three standard DC-DC converters, simplifying its design for different configurations. Furthermore the designed observers are proven to be robust against load variations, the most uncertain paramete…
Non-linear digital control improving transient response: Design and test on a multiphase VRM
2010
Multiphase interleaved buck converters are widely used for point of load applications, especially for VRMs. Performance optimization issue often clashes with size and cost requirements thus leading the industrial and academic research to focus on advanced solutions. This paper presents a control technique for multiphase VRMs including two interacting sections: the linear loop implements a PWM peak current mode control and the nonlinear subsystem modifies few linear loop parameters under load transients only. Steady-state performances are affected by the linear control only while dynamic performance optimization is a non-linear algorithm issue. The proposed control system improves the dynami…
Optimized design of high power density EMI filters for power electronic converters
2016
Nowadays, power density of power converters and related EMI filters is gaining more and more attention. This severely impacts on the design constraints in several application domains. A conventional design of the EMI filter does not guarantee the selection of components/configuration leading to the best power density. For this reason, an optimized design procedure of discrete EMI filters in terms of power density is proposed in this paper. It is based on a previously developed rule-based design procedure, introducing here additional features to obtain a more effective optimization of EMI filter's power density. The proposed approach has been validated in terms of EMI filter's performance an…
Dynamic performance enhancement of AC/DC PFC boost converters by means of MRAS observers
2015
Controlling a Power Factor Corrected (PFC) boost converter is not a trivial task, because the higher the dynamic performance, the higher is the input current distortion. On the other hand, recent applications of these converters require fast transients in response to disturbances, such as sudden variations of load power, reference voltage and input voltage. Better performance can be obtained adding a feedforward action to the traditional control scheme, using observers to estimate the input voltage and the output current. However, the actual improvement depends on the dynamic performance of the chosen observers. This paper aims at evaluating the applicability and the performance of differen…
Soft switched interleaved boost converters used as high-power battery discharge regulator for space power systems
2004
In the following years the telecommunication satellites will have a much greater power demand than nowadays. One reason for this is that the geostationary orbit required by this kind of satellites is becoming too crowded. Probably power levels of l0 kW to l00 kW will be the standard and with life duration of 25 years. It is not possible to keep 0.5 kW modules with more than 100 in parallel and therefore higher power modules (5 kW) must be used. A higher bus voltage seems also necessary and keeping a safety limit of 150 V, any voltage below it and above 100 V could meet the needs. In this paper we will propose a topology that fits the application: two soft switched interleaved boost converte…
Controlled Fault-Tolerant Power Converters for Power Quality Enhancement
2013
Power quality depends generally on the interaction of electrical power with electrical equipments. If electrical equipments operate correctly and reliably without being damaged or stressed, a suitable level of power quality is assured. On the other hand, if the electrical equipment malfunctions, is unreliable, or is damaged during normal usage, power quality is poor and probably the economical loss could be important like the technical one. In the scenario of the Distributed Generation, power quality issues will be moreover important because an higher dissemination of power conditioning equipment will be requested and this obviously increases the sources of vulnerability of the electrical s…
Guidelines for the design and implementation of the ARPCC control applied to grid-connected converters
2013
Abstract This paper presents implementation details of the adaptive robust predictive current control (ARPCC) applied to a grid-connected converter, such as feed-forward cancellation protocol, the selection of the observer gain and adaptive parameters or the sampling options, needed to get the best performance of this control. The feed-forward term cancellation permits to achieve a very low harmonic distortion in current waveforms when the voltage sensing circuits are well calibrated. A detailed gain adjustment protocol of the voltage sensing circuits is presented in this paper. Moreover, a control design procedure based on the observer gain L o boundaries and the adaptive parameters has be…
A PC-based wattmeter for accurate measurements in sinusoidal and distorted conditions: Setup and experimental characterization
2012
This paper presents the development of a high-accuracy sampling wattmeter, which can be employed with both sinusoidal and distorted input signals. The proposed personal computer (PC)-based system is a simple, portable, and low-cost solution because it is based on two commercial data acquisition boards connected to a common PC. Owing to this solution, the voltage is sensed directly, avoiding expensive voltage dividers, while the current is sensed by means of a noninductive current shunt. Commercial software is also used for data processing and implementation of the virtual instrument. The setup of the PC-based wattmeter is described, with a detailed description of the correction strategy of …
PEM Fuel Cell System Model Predictive Control and real-time operation on a power emulator
2010
Fuel Cell Systems (FCS) seem to be among the most reliable devices to produce clean energy, although they still suffer for many problems, mostly related to the fragility of the Polymer Electrolyte Membrane (PEM). Particularly, this paper focuses on the oxygen starvation, that leads both a decrease of the FCS performance and a shortening in the FCS lifetime. The purpose is to use the Model Predictive Control (MPC) and its capacity of accounting for linear constraints for managing the air system without risking to damage the fuel cell. Two control inputs and no static feed-forward actions have been used. Results show that the MPC is able to avoid the oxygen starvation, even with a sudden incr…