Energy-aware MPC co-design for DC-DC converters

In this paper, we propose an integrated controller design methodology for the implementation of an energy-aware explicit model predictive control (MPC) algorithms, illustrat- ing the method on a DC-DC converter model. The power consumption of control algorithms is becoming increasingly important for low-power embedded systems, especially where complex digital control techniques, like MPC, are used. For DC-DC converters, digital control provides better regulation, but also higher energy consumption compared to standard analog methods. To overcome the limitation in energy efficiency, instead of addressing the problem by implementing sub-optimal MPC schemes, the closed-loop performance and the control algorithm power consumption are minimized in a joint cost function, allowing us to keep the controller power efficiency closer to an analog approach while maintaining closed-loop op- timality. A case study for an implementation in reconfigurable hardware shows how a designer can optimally trade closed-loop performance with hardware implementation performance

Local control of multiple module converters with ratings-based load sharing

Multiple module dc-dc converters show promise in meeting the increasing demands on ef- ficiency and performance of energy conversion systems. In order to increase reliability, maintainability, and expandability, a modular approach in converter design is often desired. This thesis proposes local control of multiple module converters as an alternative to using a central controller or master controller. A power ratings-based load sharing scheme that allows for uniform and non-uniform sharing is introduced. Focus is given to an input series, output parallel (ISOP) configuration and modules with a push-pull topology. Sensorless current mode (SCM) control is digitally implemented on separate controllers for each of the modules. The benefits of interleaving the switching signals of the distributed modules is presented. Simulation and experimental results demonstrate stable, ratings-based sharing in an ISOP converter with a high conversion ratio for both uniform and non-uniform load sharing cases

Digital servo control of random sound test excitation

A digital servocontrol system for random noise excitation of a test object in a reverberant acoustic chamber employs a plurality of sensors spaced in the sound field to produce signals in separate channels which are decorrelated and averaged. The average signal is divided into a plurality of adjacent frequency bands cyclically sampled by a time division multiplex system, converted into digital form, and compared to a predetermined spectrum value stored in digital form. The results of the comparisons are used to control a time-shared up-down counter to develop gain control signals for the respective frequency bands in the spectrum of random sound energy picked up by the microphones

Real time analysis of voiced sounds

A power spectrum analysis of the harmonic content of a voiced sound signal is conducted in real time by phase-lock-loop tracking of the fundamental frequency, (f sub 0) of the signal and successive harmonics (h sub 1 through h sub n) of the fundamental frequency. The analysis also includes measuring the quadrature power and phase of each frequency tracked, differentiating the power measurements of the harmonics in adjacent pairs, and analyzing successive differentials to determine peak power points in the power spectrum for display or use in analysis of voiced sound, such as for voice recognition

A VHDL-AMS Simulation Environment for an UWB Impulse Radio Transceiver

Ultra-Wide-Band (UWB) communication based on the impulse radio paradigm is becoming increasingly popular. According to the IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a, UWB will play a major role in localization applications, due to the high time resolution of UWB signals which allow accurate indirect measurements of distance between transceivers. Key for the successful implementation of UWB transceivers is the level of integration that will be reached, for which a simulation environment that helps take appropriate design decisions is crucial. Owing to this motivation, in this paper we propose a multiresolution UWB simulation environment based on the VHDL-AMS hardware description language, along with a proper methodology which helps tackle the complexity of designing a mixed-signal UWB System-on-Chip. We applied the methodology and used the simulation environment for the specification and design of an UWB transceiver based on the energy detection principle. As a by-product, simulation results show the effectiveness of UWB in the so-called ranging application, that is the accurate evaluation of the distance between a couple of transceivers using the two-way-ranging metho

A broadband FFT spectrometer for radio and millimeter astronomy

The core architecture, tests in the lab and first results of a Fast Fourier Transform (FFT) spectrometer are described. It is based on a commercially available fast digital sampler (AC240) with an on-board Field Programmable Gate Array (FPGA). The spectrometer works continuously and has a remarkable total bandwidth of 1 GHz, resolved into 16384 channels. The data is sampled with 8 bits, yielding a dynamic range of 48 dB. An Allan time of more than 2000 s and an SFDR of 37 dB were measured. First light observations with the KOSMA telescope show a perfect spectrum without internal or external spurious signals.Comment: Astronomy and Astrophysics, in pres

Active Current Surge Limiters With Inrush Current Anticipation

Active current surge limiters and methods of use are disclosed. One exemplary system, among others, comprises a current limiter, including an interface configured to be connected between a power supply and a load; a disturbance sensor, configured to monitor the power supply for a disturbance during operation of the load; and an activator, configured to receive a control signal from the disturbance sensor and to activate the current limiter based on the control signal.Georgia Tech Research Corporatio