Applying for 3 utility model patents, the first feature is A, the second feature is B, and the third feature is A B. Does the third one conflict with the first and second ones?

No, first of all you can apply for all three together, but in fact you can only apply for A.B or A B, because you are patent protection for a process, but as the business person negotiating with you The clerk will also ask you to apply for all three, because the commission will increase and your protection will not be less.