Flat roof triangle (or A-frame/tripod) solar mount structures are essentially the industry standard for getting panels tilted on a flat surface without compromising the roof

"Triangular" racks, these are ground-mounted style structures adapted for flat roofs. They are engineered frameworks, typically made of aluminum for lightweight corrosion resistance, that elevate and tilt solar panels at an optimal angle (usually 15-30 degrees) on an otherwise flat surface.