Satellites are not perpetual motion devices, they just look like it.

When a body orbits the earth it is essentially falling due to the force of gravity. Think if it like this. When you throw a ball it falls to the ground in an arc. Now, what if you could throw the ball so hard that the arc matched the curve of the earth? It would be falling but it would never hit the ground. Of course the horizontal component of velocity would be lost due to friction in the air but if you did the same thing in space there would be (almost) nothing to counteract it and you would have a satellite. 

In reality there is "dust" in space in the form of micrometeorites so even though they are tiny when a satellite strikes them a tiny amount of that horizontal vector of energy is lost.  Eventually all satellites will fall out of orbit, unless they have engines to help maintain thier orbit.

Now here is something that will really blow your noodle. A wire passing through a magnetic field will generate a weak current. The earth is surrounded by a magnetic field. So if you put a wire coil inside a satellite and aligned it correctly with the earth’s magnetic field it would generate electricity as it orbits. Wow! A perpetual motion device! Sorry not quite. It takes mechanical energy to force the wire through a magnetic field and convert it to electricity. The mechanical energy to push the wire through the magnetic field would come from the horizontal component of force in the satellites orbit, slowing it down and eventually causing it to crash back into the earth.

I can desing a perpetual motion device on paper and provide sound math but the problem is that all systems have points where energy is lost.  Once you factor in these points of loss; friction, sound, heat, collisions, air resistance, etc. The desings all come to a halt.

well I have thought of this topic before and have something quite similar to yours.

1. A moving platform that is powered by friction panels, as the platform moves it runs over Numerous panels that absorb friction as power then the power is used to run the moving platform.

2.Two magnets moving in cricular motion. As they move circularly the poles of the magnets repel Each other accurately enableing the magnet to continue spinning.

3. A satelite above earth attached with solar panels. Since the satelite  never goes on the night side of the earth it can forever generate power.

4. 2 solar panels on one object. One solar panel powers the object while another one stores Energy into some kind of batery in the object. So when night comes the stored energy is used and When day comes the solar energy is used.

5.Waves. I might be wrong but I think waves in the ocean are constantly in motion. If so a device Could be made to use this motion as energy or power

I'm not sure if any of these are possible. I'm only 14 years old afterall and they are just my logical thoughts. I don't know if the energy produced is sufficient for perpetual motion.