An isolated boost converter includes first and second switches that are switched simultaneously, a transformer and an energy storage capacitor on the primary side of the transformer for storing energy received from input power source. In one embodiment, when the first and second switches are closed, the energy in the capacitor is transferred to the output load while a boost inductor is charged, and when the first and second switches are open, the boost inductor provides energy from the input voltage source to supply the load and to charge the capacitor, In one embodiment, a third switch is provided to relieve the voltage stress on the secondary side.
A soft-switched boost converter includes an active snubber to provide soft switching of all semiconductor components. Specifically, the current ("turn-off current") in the rectifier is switched off at a controlled rate, the main switch is closed under zero-voltage switching (ZVS) condition, and the auxiliary switch in the active snubber is opened under zero-current switching (ZCS) condition. As a result, switching losses are reduced with beneficial effects on conversion efficiency and EMC performance.
A boost control module operates semiconductor switches of a boost converter circuit in an avalanche mode to precharge a boost output capacitor. The boost control module comprises a switching module that complementarily transitions a first semiconductor switch and a second semiconductor switch between ON and OFF states when a current does not exceed a maximum current threshold. The switching module transitions the first semiconductor switch and the second semiconductor switch to the OFF state when the current exceeds the maximum current threshold. The switching module maintains the first semiconductor switch and the second semiconductor switch in the OFF state until at least one of the inductor current is less than or equal to a minimum current threshold.
The invention relates to novel variants of cytochrome P450 oxygenases. These variants have at least one mutation improving their ability to use peroxide as an oxygen donor as compared to the corresponding wild-type enzyme. The variants also have at least one mutation improving thermostability as compared to the parent enzyme or corresponding wild-type enzyme. Preferred variants include cytochrome P450 BM-3 heme domain variants having L52I, I58V, F87A, H100R, S106R, F107L, A135S, M145A/V, A184V, N239H, S274T, L324I, V340M, I366V, K434E, E442K, and/or V446I amino acid substitutions.
The invention relates to novel variants of cytochrome P450 oxygenases. These variants have an improved ability to use peroxide as an oxygen donor as compared to the corresponding wild-type enzyme. These variants also have an improved thermostability as compared to the cytochrome P450 BM-3 F87A mutant. Preferred variants include cytochrome P450 BM-3 heme domain mutants having I58V, F87A, H100R, F107L, A135S, M145A/V, N239H, S274T, L324I, I366V, K434E, E442K, and/or V446I amino acid substitutions.
A power factor correcting power supply includes an input stage power converter and an output stage power converter. The input stage power converter includes a plurality of series connected boost switches and a power factor correction controller. The power factor correction controller may direct the operation of the boost switches with series interleave phasing to perform power factor correction and voltage regulation. The boost switches are supplied input voltage and input current from a power source. The input voltage is converted to a DC boost voltage by high frequency series interleaved switching of the boost switches. The DC boost voltage is converted to a DC output voltage by the output stage power converter. The DC output voltage is provided on a DC rail for a load of the power factor correcting power supply.
