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Hamill D.C. Lee C.Q. Liu R. 《IEEE transactions on aerospace and electronic systems》1991,27(3):564-566
In a recent paper by C.Q. Lee et al. (ibid., vol.25, no.6, p. 844-7, Nov. 1989), the authors analyzed a DC-DC converter that they termed the LLC-type PRC (parallel resonant converter). Its resonant network contains three active components-two inductances and a parallel capacitance-and as a consequence the converter might be expected to have third-order dynamics. But Lee et al. employed a matrix transformation to show that the behavior of the circuit may be represented as a state-plane trajectory, as for a second-order circuit. The purpose of this contribution is to show that the converter has a zero-frequency eigenvalue, associated with undesirable circulating DC. The second-order dynamics exhibited by the third-order converter are explained by an application of Thevenin's theorem. Some aerospace applications of the LLC-type parallel resonant converter (PRC) are discussed. In their reply, the authors show that the circulating direct current does not exist in the practical converter circuit 相似文献
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When low ripple is required from a switched mode dc-dc converter, dissipative active filters offer an alternative to passive LC and coupled inductor filters. Analytical and experimental results are presented for a simple active ripple filter. The filter employs a pair of current transformers as sensors for feedforward and feedback control and two metal-oxide-semiconductor field-effect transistors (MOSFETs) as cancellation current drivers. Measurements demonstrate good ripple attenuation up to 5 MHz, more than 70 dB being obtained at 100 kHz, the switching frequency of a test converter. The overall efficiency was measured as 95%, with room for further improvement. The filter is suitable for input and output smoothing in dc-dc converters for aerospace and other critical applications 相似文献
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