X2 on what Dayle1 stated.
This is and has been an issue,on certain modelsfor the last ten years.
Don't try to overboost the size of breakers, to do so is asking for serious trouble or fire hazard.
We've experienced the exact problem in our CF28CK. I've changed all of the 30a and 20a breakers at least twice, reworked the postions of the breakers and about everything else you can think of.
About the only thing that I've found that works is a small auto type AC fan that will produce about 500/800 cfm of air, directly in front of the electrical control panel.
My suggestion is use the AC very sparely in the day and try to leave the overhead vents open, weather permitting. High or very high humidity will cause the AC of work much harder.
When the AC 20abreaker pops, leave it alone until it cools down. It's doing exactly what it's supposed to do with excessive heat build up.
Depending on how your breakers are positioned in the elec control box, you may be able to move the AC 20a breaker away from the main 30a breaker. Some of the guys have done this sucessfully.
Another option is to check and see if you have an empty CB slot, if so you can seperate the 30a and 20a AC breaker. If your electrical control panel is only a three lug panel, then it's not likely that you'll have room to move the breakers around.