This paper presents a field programmable gate array (FPGA) implementation of a digital circuit that measures in real-time first harmonics of voltage and current medium-frequency (25 kHz - 70 kHz) induction-heating cooking appliances. The... more
This paper presents a field programmable gate array (FPGA) implementation of a digital circuit that measures in real-time first harmonics of voltage and current medium-frequency (25 kHz - 70 kHz) induction-heating cooking appliances. The inverter output voltage and load current are sensed using first-order delta-sigma () analog to digital converters. The coefficients of the Discrete-Time Fourier Series (DTFS) of voltage
Research Interests: Engineering, Electronic Engineering, Harmonic Analysis, Big Dams, Digital Circuits, and 15 moreModulation, FPGA implementation, Field Programmable Gate Array, Real Time, First Order Logic, Induction Heating, Digital Circuit, Harmonics, Digital Filters, Fourier Series, Low Pass Filters, Data Stream, Delta Sigma Modulator, Analog to Digital Converter, and Low pass filter
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ABSTRACT Nowadays, induction heating (IH) technology is dominating the domestic cooking market due to its advantages such as safety, cleanness, and high efficiency. Such high efficiency and high power density implementations are achieved... more
ABSTRACT Nowadays, induction heating (IH) technology is dominating the domestic cooking market due to its advantages such as safety, cleanness, and high efficiency. Such high efficiency and high power density implementations are achieved by means of resonant power converters and, consequently, these need to be accurately controlled. This paper proposes a field-programmable gate array-based online power measurement system which allows the control system to perform the proper power control. The proposed power measurement system measures the output power from the digitized output voltage and current through two low-cost 1-bit second-order ΣΔ analog-to-digital converters. The bitstreams have been analyzed and, taking into account the results, several measurement approaches have been proposed and analyzed. Then, a noise sensitivity analysis has been performed in order to verify the proposed measurements methods. The analytical and simulation results have been tested through a resonant power converter applied to domestic IH whose switching frequency varies from 30 to 80 kHz. A statistical analysis of the implemented measurement approaches has been carried out in order to evaluate the system accuracy. Finally, the selected measurement method has been verified for several vessels. As a conclusion, an accurate and cost-effective output power measurement system is obtained, which can be applied to any resonant converter in the frequency operation range.
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Domestic induction heating applications require an accurate control of the power delivered to the vessel to be heated, ensuring power topology operation under safety conditions. Particularly, this paper is focused on applying a power... more
Domestic induction heating applications require an accurate control of the power delivered to the vessel to be heated, ensuring power topology operation under safety conditions. Particularly, this paper is focused on applying a power control of two induction heating loads in a dual-half bridge sharing a common resonant capacitor. This topology leads to a control strategy harder than the classical arrangement which features a dedicated resonant capacitor. A Phase Shift Square Wave Modulation (PSSWM) is performed to control the output powers of the vessels to be heated. Thus, the considered plant is a two-input two-output (TITO) system. The two control inputs are (fsw, θ) and the two outputs are (P1, P2). Since the transfer function matrix is not diagonal, the Relative Gain Array (RGA) methodology is used to analyze if a multi-loop control is feasible. Due to the fact that the system is strongly coupled a centralized control must be applied. Therefore, the aim of the paper is to apply a decoupling control to handle the interactions. Simulation and experimental results in an induction heating prototype are performed in order to validate the proposed control technique.
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ABSTRACT Digital control has significantly advanced in the last decade enabling the implementation of higher performance controllers using digital devices such as microcontrollers, DSPs or FPGAs. The design and implementation of... more
ABSTRACT Digital control has significantly advanced in the last decade enabling the implementation of higher performance controllers using digital devices such as microcontrollers, DSPs or FPGAs. The design and implementation of controllers using FPGAs is often a challenging and time-consuming task. In order to improve this process, high level synthesis tools allow the use of high-level programming languages, easing the design and simulation process and enabling a straight-forward design space exploration. This paper details the overall design process using high level synthesis tools and presents as a representative example a full-state feedback controller for a buck converter using single-precision floating point representation. The main implementation and experimental results are summarized, highlighting the main benefits and drawbacks of this approach.
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ABSTRACT This paper proposes a field-programmable-gate-array-based emulator of the series-resonant half-bridge inverter for measuring the inverter efficiency and detecting hard-switching conditions. The proposed emulator is able to... more
ABSTRACT This paper proposes a field-programmable-gate-array-based emulator of the series-resonant half-bridge inverter for measuring the inverter efficiency and detecting hard-switching conditions. The proposed emulator is able to compute the converter operating conditions and efficiency each mains half-cycle, providing useful information for the control unit. In addition, it is designed taking advantage of recent advances in high-level synthesis tools, which provides an optimized and straightforward implementation. The proposed emulator has been applied to an induction heating (IH) appliance as an example of efficient and environmentally friendly appliances with a major economic and social impact. The obtained results are compared with classical offline simulation and experimental measurements, proving that the proposed emulator achieves the required accuracy for the IH application. As a consequence, the proposed system can be used for improving the system safety and optimizing the converter efficiency and reliability.
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ABSTRACT Current technology for domestic induction heating requires to deliver a wide range of power (50 W–3.5 kW) to the vessel to be heated. In addition to this, the considered power control strategy must ensure high reachability and... more
ABSTRACT Current technology for domestic induction heating requires to deliver a wide range of power (50 W–3.5 kW) to the vessel to be heated. In addition to this, the considered power control strategy must ensure high reachability and compliance with some constraints. This work is focused on applying the Phase Shift Control (PSC) modulation to control the power delivered to two induction loads. The considered topology is based on two half-bridge resonant inverters that control two domestic induction heating loads sharing a single resonant capacitor. The two outputs to be controlled are coupled, leading to a harder control problem. Therefore, a Particle Swarm Optimization (PSO) algorithm based on the gradient information is proposed to perform the power control by considering the PSC modulation. Finally, simulations are discussed and verified with some experimental results obtained in a prototype induction heating system.
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The development of ad-hoc control architectures is a time-consuming task which is often required to design and evaluate power converters. In this paper, an FPGA-based versatile control architecture test-bench which enables to evaluate and... more
The development of ad-hoc control architectures is a time-consuming task which is often required to design and evaluate power converters. In this paper, an FPGA-based versatile control architecture test-bench which enables to evaluate and implement different control strategies applied to different power converter topologies is proposed. It is based on a hardware/software codesign by means of MicroBlaze softcore processor and
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This paper presents a field programmable gate array (FPGA) implementation of a digital circuit that measures in real-time the first harmonic load impedance of medium-frequency (25 kHz – 75 kHz) induction-heating cooking appliances. The... more
This paper presents a field programmable gate array (FPGA) implementation of a digital circuit that measures in real-time the first harmonic load impedance of medium-frequency (25 kHz – 75 kHz) induction-heating cooking appliances. The load impedance of these systems, which consist of a planar inductor coupled to a pan, depends on the pan material, temperature, and frequency. For this reason,
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This paper presents a method to measure the control-to-output transfer function of dc-dc converters in open-loop. A sinusoidal perturbation is injected to the nominal value of the duty cycle, and a dual-phase lock-in algorithm is off-line... more
This paper presents a method to measure the control-to-output transfer function of dc-dc converters in open-loop. A sinusoidal perturbation is injected to the nominal value of the duty cycle, and a dual-phase lock-in algorithm is off-line applied to process the digitized input and response signals in order to compute the gain and phase of the transfer function. Lock-in algorithm is
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ABSTRACT Modern digital electronics courses usually include hardware description languages as a useful tool to implement relatively complex digital designs using programmable logic devices. These languages are close to the final hardware... more
ABSTRACT Modern digital electronics courses usually include hardware description languages as a useful tool to implement relatively complex digital designs using programmable logic devices. These languages are close to the final hardware architecture, but usually lead to long and complex design procedures. To overcome this limitation, high level synthesis tools provide an intuitive and straight-forward design flow using well-known programming languages such as C. This paper deals with the inclusion in a digital electronics course high-level synthesis tools to provide the student with a wider vision and additional design tools. An application example focused on digital control of power converters is provided, and the main benefits and drawbacks arisen are highlighted.
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Two-dimensional discrete wavelet transforms (DWTs) have become a very powerful tool in computer vision. When implementing DWT in hardware, finite precision arithmetic introduces quantization errors. The hardware designer must look for the... more
Two-dimensional discrete wavelet transforms (DWTs) have become a very powerful tool in computer vision. When implementing DWT in hardware, finite precision arithmetic introduces quantization errors. The hardware designer must look for the optimum register length which, while ...
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ABSTRACT Resonant power converters are widely used in domestic induction heating (IH) cooktops due to their advantages in terms of size, efficiency, and power density. The wide range of different induction loads (with different electrical... more
ABSTRACT Resonant power converters are widely used in domestic induction heating (IH) cooktops due to their advantages in terms of size, efficiency, and power density. The wide range of different induction loads (with different electrical equivalent) and the wide range of required output powers, lead to the load identification as a mandatory and specially challenging aspect. This identification is needed to improve static operation, by identifying IH load that may lead to too high currents through the inverter, and dynamic operation, by correcting the gain of the digital controller according to the identified IH load. This work focuses on applying and evaluating the Particle Swarm Optimization (PSO) algorithm to identify the system load in domestic induction heating. Therefore, the obtained load parameters lead to a more efficient control strategy of the delivered power according to the user requirements. Simulation and experimental results in an induction heating prototype are performed in order to validate the proposed identification algorithm.
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Abstract - Wavelet Transforms have become a very powerful tool in Computer Vision. They are computationally very intensive and real-time processing cannot be achieved with software implementations on a conventional Von-Neumann... more
Abstract - Wavelet Transforms have become a very powerful tool in Computer Vision. They are computationally very intensive and real-time processing cannot be achieved with software implementations on a conventional Von-Neumann programmable computer. We have followed a top- ...
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Digital controllers implemented in an FPGA for switching power converters are becoming an important alternative to the traditional analog solutions. Assuming that the digital controller is described using a hardware description language,... more
Digital controllers implemented in an FPGA for switching power converters are becoming an important alternative to the traditional analog solutions. Assuming that the digital controller is described using a hardware description language, this work gives an overview of models, and mixed-signal simulation alternatives that support the simulation as a whole of the digital controller with the power electronic circuit, in
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ABSTRACT This paper presents a method to measure off-line the frequency-to-output-power transfer function of a resonant inverter in open-loop. This method is applied to a half-bridge series resonant inverter for domestic induction heating... more
ABSTRACT This paper presents a method to measure off-line the frequency-to-output-power transfer function of a resonant inverter in open-loop. This method is applied to a half-bridge series resonant inverter for domestic induction heating applications. A sinusoidal perturbation is injected to the nominal value of the switching frequency, leading to a perturbation in the power transferred to the load. The Discrete Fourier Transform (DFT) is used off-line to process the digitized input and outputs in order to compute the gain and phase of the transfer function at the injected perturbation frequency. The digitized input is the saw-tooth waveform used in the trailing-edge modulator. This waveform is generated with a commercial function generator that allows modulating the frequency with an internal sine waveform. Since the internal modulation signal is not accessible, the sinusoidal switching frequency perturbation is off-line obtained by processing the ramp slope of the saw-tooth waveform. The digitized outputs are the inductor current and load voltage, which are processed to obtain the moving average output power. The algorithm accuracy is firstly evaluated in simulation, leading to an appropriate method to extract the ramp slope of the saw-tooth waveform. Finally, the proposed method is experimentally verified, evaluating the validity range of the EDF model extended for several harmonics applied to resonant power converters.
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Page 1. Reusing IPs to implement a SPARC SoC Serafín Olcoz, Alfredo Gutiérrez Denis Navarro SIDSA Universidad de Zaragoza olcoz@sidsa.es; luis@sidsa.es denis@posta.unizar.es Abstract. We present the gained experience ...
A circuit that receives and process analog signals from the telephone line is presented; it generates dialing signals, and controls a number of electrical functions (power supply, ...) and mechanical functions (hanging, money-box, ...).... more
A circuit that receives and process analog signals from the telephone line is presented; it generates dialing signals, and controls a number of electrical functions (power supply, ...) and mechanical functions (hanging, money-box, ...). This circuit replaces digital and analog electronic components in an existing printed circuit board. One of its main functions is to reduce phone operating power consumption
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ABSTRACT Recent advances in power electronic converters highly rely on the development of new control algorithms. These implementations often require complex control architectures featuring microprocessors, digital signal processors, and... more
ABSTRACT Recent advances in power electronic converters highly rely on the development of new control algorithms. These implementations often require complex control architectures featuring microprocessors, digital signal processors, and field-programmable gate arrays (FPGAs). Whereas software implementations are feasible for most power electronics practitioners, FPGA implementations with ad-hoc digital hardware are often a challenging design task. This paper deals with the design and development of control systems for power converters using high-level synthesis tools. In particular, the Xilinx Vivado HLS tool is evaluated for the design of a computationally demanding application, the real-time load estimation for resonant power converters using parametric identification methods. The proposed methodology allows the designer to use a high-level description language, e.g., C, to describe the identification algorithm functionality, and the tool automatically generates the hardware floating-point data-path and the control unit. Besides, it allows a fast design-space exploration through synthesis directives, and pipelining and parallelization are automatically performed to meet timing constraints. The evaluation performed in the study-case control architecture shows a significant design complexity reduction. As a consequence, high-level synthesis tools should be considered as a new paradigm in accelerating digital design for power conversion systems.
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ABSTRACT A simple and successful design for a sigma-delta (SigmaDelta) modulator with only digital active components is presented. Low frequency compensation of the input threshold variations of the digital gate used as a comparator... more
ABSTRACT A simple and successful design for a sigma-delta (SigmaDelta) modulator with only digital active components is presented. Low frequency compensation of the input threshold variations of the digital gate used as a comparator achieves good spurious-free dynamic range. The only drawback is the addition of a low cutoff frequency, which results in an AC-coupled analogue-to-digital converter.
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Janus is a modular, massively parallel, and reconfigurable FPGA-based computing system. Each Janus module has one computational core and one host. Janus is tailored to, but not limited to, the needs of a class of hard scientific... more
Janus is a modular, massively parallel, and reconfigurable FPGA-based computing system. Each Janus module has one computational core and one host. Janus is tailored to, but not limited to, the needs of a class of hard scientific applications characterized by regular code structure, unconventional data-manipulation requirements, and a few Megabits database. The authors discuss this configurable system's architecture and focus on its use for Monte Carlo simulations of statistical mechanics, as Janus performs impressively on ...
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ABSTRACT We describe Janus, an application-driven architecture for Monte Carlo simulations of spin glasses. Janus is a massively parallel architecture, based on reconfigurable FPGA nodes; it offers two orders of magnitude better... more
ABSTRACT We describe Janus, an application-driven architecture for Monte Carlo simulations of spin glasses. Janus is a massively parallel architecture, based on reconfigurable FPGA nodes; it offers two orders of magnitude better performance than commodity systems for spin glass applications. The first generation Janus machine has been operational since early 2008; we are currently developing a new generation, that will be on line in early 2013. In this paper we present the Janus architecture, describe both implementations and compare their performances with those of commodity systems.
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Digital controllers implemented in an FPGA for switching power converters are becoming an important alternative to the traditional analog solutions. Assuming that the digital controller is described using a hardware description language... more
Digital controllers implemented in an FPGA for switching power converters are becoming an important alternative to the traditional analog solutions. Assuming that the digital controller is described using a hardware description language (VHDL), the ADVance MS mixed-signal simulation tool is used to simulate in closed loop the digital controller in order to analyze the finite word-length effects. The use of