I know that Bentley in the United States is a professional company in the field of equipment vibration monitoring. It offers proven vibration monitoring solutions for the thermal power, wind power and petrochemical industries.
There is also the European company B&K.
There are also some in China, which can be searched online, such as Zhongneng Technology, Tangzhi Technology, etc.
The source of energy for the wind turbine is natural wind. The wind speed changes all the time, and the density also changes with temperature, so the speed of the wind wheel also changes all the time. If you want the motor to directly output 50Hz. For electricity, there must be a speed stabilizing device, and the generator can be a synchronous machine. However, there are currently very few synchronous generators in Switzerland and abroad. The engines cOn-grid wind power uses frequency converters to connect to the grid, while off-grid wind power typically uses a battery inverter method.
In short, if you want to get electricity with a stable frequency, you must have a device to stabilize the motor speed or use an electronic device to stabilize the frequency.