Half-bridge

This is going to be a eurrent-mode eontrolled half-bridge topology. It will have soft-start to minimize the start-up surge of the system. The power supply must meet UL, CSA, and VDE safety regulations. 

I have decided to use a current transformer to sense the primary current waveform, since resistive methods are impractical in the half-bridge topology. Several transformer manufacturers make current transformers for such a purpose wound on a toroidal core. Coilcraft makes current transformers with 50, 100, and 200 turns on their secondaries. The secondary voltage must be determined in order to have representative current waveforms of the level to work with the control IC. The voltage needed on the output of the current transformer is... 

Figure 3-77 Schematic of a 100 kHz, 280W, half-bridge converter.

A Zero Voltage Switched Quasi-resonant Off-line Half-bridge Converter... 

This converter is intended to function as a bulk power supply for a distributed system. It has only one +28VDC output at 10 A. This is going to be a classic ZVS quasi-resonant half-bridge converter that is, variable frequency, voltagemode controlled with averaging overcurrent protection. It is representative of the designs using the available control ICs on the market today. 

The apparent second order rate constants10 of f-BuX with Me3 A1 at —40 °C are given in Table 1. The proposed mechanism to explain the above results was as follows. A half-bridged intermediate is assumed to be formed in the presence of MeCl. 

Any Buck-derived topology (e.g., the Forward converter, the Half-Bridge, the Push-Pull, the Full-Bridge, etc.) needs an output choke. Otherwise it is akin to running a Buck without its inductor—you can thereby create a dead short cross the input supply rails. 

Figure 3.20 Half-bridge inverter switching waveforms.

Tipton, C. W., et al., Half-Bridge Inverter Using 4H-SiC Gate Turn-Off Thyristors, IEEE Electron Device Letters, Vol. 23, 2002, pp. 194-196. 

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