Yes, the permanent magnet synchronous motors can be used as generators, but the power of such motors is limited, generally, tens of watts, the output voltage is unstable and the efficiency is low.

Due to limitations in power and efficiency, it does not make sense to change permanent magnet synchronous motors into generators.

The electric motor is an electrical device that converts electrical energy into mechanical energy and can reuse mechanical energy to generate kinetic energy to drive other devices. There are many types of motors, but they can be roughly divided into AC motors and DC motors for different occasions.

The motor refers to an electromagnetic device that realizes the conversion or transmission of electric energy according to the law of electromagnetic induction. Its main function is to generate driving torque as a power source for electrical appliances or various machinery.

The generator is a device that converts kinetic energy and other forms of energy into electrical energy. Through the prime mover, the energy stored in various primary energy sources is converted into mechanical energy and then converted into electrical energy by a generator, which is sent to various power-consuming occasions through the power transmission and distribution network. The principle of the generator and the motor are basically the same, and the directions of energy conversion are different. Its main function is to convert mechanical energy into electrical energy. At present, the most commonly used is to use thermal energy, water energy, etc. to push the generator rotor to generate electricity.