APPENDIX 1.A : BOOST CHOKE FOR POWER FACTOR CORRECTION: DESIGN EXAMPLE

This example is for the choke L1 in Part 4, Sec. 1.14.3.

1.A.1 : BASIC DESIGN PARAMETERS FOR L1

1.A.2 : CHOICE OF CORE TYPE

For this design, we will consider an iron powder core material (rather than a ferrite or MPP) because the 50-kHz ripple current is quite small compared to the 120-Hz low-frequency current. This should allow the use of a low-permeability, higher-loss iron powder material, which would be much more cost-effective.

1.A.3 : SIZE OF CORE

This can be established by an iterative design process (choose a core size and try an outline design), by selection based on experience, or by using a software program supplied by the manufacturer.

Micrometals provides suitable software programs for its cores free of charge. As an example, we will consider a Micrometals E305 core size. The data for this core will also be found in Micrometals Power Conversion & Line Filter Applications data book. ⁹⁰ Other manufacturers make similar cores.

1.A.4 : CORE MATERIAL

To minimize the core loss and maintain a near-linear inductance over...