What kind of surface are you using your laptop on? Might need to invest in a laptop cooler. Laptops are designed to turn off when they run too hot. If the fan exhausts are being blocked/not dissipating enough heat, then that would result in the temps getting hot enough to turn it off.
this is simply a overheating of the processor issue. Just check out where you keep your laptop, keep it on flat surface or it might be your fans aren't working or something is blocking the vents. I hope this helps