Hybrid-switching asymmetrical half-bridge flyback DC-DC converter
This paper proposes a hybrid-switching technique for asymmetrical half-bridge flyback converter. In this topology, the duty loss can be minimized because the active switches can achieve zero-voltage-switching (ZVS) and the output diode can be turned off at zero current, which result in higher efficiency, higher power density and universal input voltage range (90-264V). Moreover, this technique doesn't require any addition of components into the original topology and still employ the fixed frequency PWM, therefore the control method is simple and straightforward, while still being highly reliable.
Analysis, design and implementation of an asymmetrical half-bridge converter
This paper presents the system analysis and circuit design of a half-bridge zero voltage switching (ZVS) flyback converter with synchronous rectifier. The leakage inductance and output capacitance of active switches are used to realize ZVS operation during the transition state between two switches. The switching power loss of active switches can be reduced to minimum due to the ZVS operation such that the high efficiency circuit can be achieved. The circuit operation principle, mathematical analysis, and design example of a half-bridge ZVS flyback converter with synchronous rectifier are explained and analyzed. The synchronous rectifier is used at the transformer secondary side to further reduce the conduction loss and to increase the circuit efficiency. Finally the experimental results from a 24 V/7 A output load with 100 kHz switching frequency prototype circuit are provided to verify the theoretical analysis
Treatment of sentence production deficits in aphasia: A linguistic-specific approach to wh-interrogative training and generalization
Abstract The present research examines the effects of a linguistic-specific treatment on acquisition and generalization of wh-interrogative structures in two aphasic subjects presenting with deficit patterns consistent with agrammatism. The underlying linguistic representation of sentence structures selected for treatment and generalization was considered based on aspects of Chomsky's (1981) Government Binding (GB) theory, and a linguistic-based, wh-movement treatment strategy was implemented. Using a single-subject multiple-baseline design across behaviours and subjects, the effects of treatment were explored by examining generalization patterns across wh question forms requiring wh-movement (movement of a direct object NP to COMP). Within question form generalization also was evaluated by examining formulation of untrained sentences of varied complexity—with complexity defined in terms of the number of phrasal nodes in the d-structure representation of sentences. Results indicated that for both subjects...