Noise is heard when the car stops

Hello everyone, I'm very happy to become a member of the Prius family not long ago. My car is a 2009 touring with 97,000 miles. The car runs well, but I have been hearing this noise for about a week. It used to be able to stop for a while, but now it seems that I can hear it all the time. It is a sharp buzzing sound, which is very obvious every time I stop or park. I found that this sound comes from the electric motor and the engine. I put my ear close to the engine to listen, and the noise of the electric motor and the engine is different. The electric motor is very similar to the noise I heard, but the engine noise sounds sharper. As a tinnitus patient, I hate this noise. Does anyone know where the problem comes from?