My suggestion is to implemente a kind of inverse D´Alemberg, where lot increase after win and decrease back to initial lot after a loss

Example: 

Starting lot =0.01 ; TP=10 pips

-$1

-$1

-$1

-$1

+$1

+$2

-$3

-$1

+$1

+$2

+$3

>>> After this trade account has increased equity by $1, then next trade will have initial lot 0.01  because this sequence of trades is already in profit (assuming no swaps and no commissions). A parameter could be set to let the user define if lot increase or go back to initial lot after equity is higher than its previous high.

Lot 0.01 x 10pips = $1