Jan 14, 2021
The difference between converter and frequency converter
The purpose of converter and inverter control is different:
The main purpose of the converter is to adjust the current, and the main purpose of the inverter is to adjust the frequency. But both may change the frequency.
The converter that drives the doubly-fed generator in order to allow the doubly-fed generator to generate alternating current that is exactly the same as the grid frequency. The converter injects a variable frequency alternating current into the rotor of the doubly-fed generator to generate a rotating electromagnetic field; and requires the speed of this electromagnetic field plus the mechanical speed on the generator shaft to be equal to the synchronous speed (for example, a double space with 4 poles) The synchronous speed of the engine is 1500r/min), so that the electromagnetic field on the rotor cuts the stator coil to generate alternating current. The frequency, phase, and voltage of this alternating current are completely consistent with the grid, so that the engine can be connected to the grid to generate electricity. The frequency is actually adjusted here, but the purpose is to make the output frequency of the generator the same as that of the grid. In terms of the effect of power generation, the current is adjusted.
The frequency converter that drives the asynchronous motor changes the speed by adjusting the frequency. Its fundamental function is to provide AC power with varying frequency to the asynchronous motor, control the starting current of the motor, reduce the voltage fluctuation of the power line, adjust the torque limit, etc.; or let the motor rotate according to a certain control method and the speed can be smoothly adjusted to achieve energy saving or The process of improving the production process.
Broadly speaking, frequency converters, inverters, transformers, etc. can all be called converters.