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Consumer and household applications require cheap AC/DC power supplies complying with EMC standards. Passive solutions are bulky and do not provide output voltage stabilization. Active solutions based on power factor correctors (PFCs) with high-frequency switching provide compactness and regulation capability, but are generally expensive due to the need for(More)
The development of more efficient hermetic compressors for refrigeration involves a sound analysis of the heat exchanges inside the machine to evaluate the interaction among compressor structure, flow characteristics, refrigerant properties and operative conditions. This work presents a computational procedure for the steady-state thermal analysis of a(More)
In this work a previous steady-state model [1] of a hermetic reciprocating compressor has been improved using an unsteady-state analysis of the compression cycle which allows a direct computation of the heat, work and mass flow rates. The new model requires the geometry of the machine, refrigerant inlet temperature and pressure, vapour discharge pressure,(More)
— This paper presents the practical implementation of a fully digital control for boost power factor preregulators (PFP's). The control algorithm, which is simple and fast, provides a significant improvement in the system's dynamic performance compared to usual analog control techniques. The paper discusses the design criteria and the actions taken for the(More)
Switch-mode power supplies represent a particular class of variable structure systems (VSS). Thus, they can take advantage of non-linear control techniques developed for this class of systems. In this paper the so called sliding mode control is reviewed and its application to switch-mode power supplies is discussed. Sliding mode control extends the(More)
The paper presents the implementation of a fully digital controller for a boost type integrated AC/DC PWM converter. The considered converter has the following basic features: high power factor, full control of the output DC voltage, high-frequency line filter inductor and insulation transformer. Its main advantage is the complete integration of a rectifier(More)
The use of an active voltage clamp in insulated DC/DC converters allows a limitation of the voltage stress due to transformer leakage inductance, a reduction of the commutation losses, and an increase of the switching frequency. It is therefore important to ensure soft switching in the whole operating range, penalty a considerable worsening of converter(More)
A modification of the series resonant converter topology is presented which extends converter operation from no-load to full-load. This result is accomplished by adding two switches at the secondary-side bridge rectifier, thus improving output voltage control. The resonant inverter can be operated either at constant switching frequency, even for the(More)
Control techniques that optimize the behaviour of pulse-width modulation (PWM) rectifiers for magnet supplies are examined. Different control strategies, both with preprogrammed and variable switching patterns, are examined and compared in terms of optimization of the system performance. Optimum digital PWM, multilevel delta modulation, and hybrid PWM/delta(More)