Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 12:11am 16 Nov 2020
The rule of thumb way of arriving at an optimum gap is to monitor the ripple current at full load. If the gap is way too large, you lose too much inductance, and ripple current will be high. If the gap is too small, it will saturate, and again ripple current will be high.
Optimum gap will produce a definite minimum of ripple current, which you can find experimentally fairly easily. That will produce the highest dynamic inductance under the exact conditions under which it operates in the real world. Theory can only steer you in the right direction, the real proof is in the final testing.