How does a frequency converter change the motor speed?

The frequency converter achieves the goal of changing the motor speed by changing the frequency and voltage of the power supply to the motor. The relationship between the torque and speed output by the motor can be expressed by the following formula:
T = (k×U×f)/n
Among them, T is the output torque of the motor, U is the input voltage of the motor, f is the power frequency of the motor input, and n is the motor speed.
According to the above formula, it can be seen that the speed of the motor can be adjusted by changing the power frequency. And the frequency converter utilizes this principle to change the motor speed by changing the power frequency and voltage. Specifically, the frequency converter converts the DC voltage of the power supply into AC voltage, and controls the motor speed by changing the frequency and voltage of the power supply.
The frequency converter internally rectifies, filters, and inverts the DC voltage of the input power supply, and then controls the output voltage and frequency through PWM technology (pulse width modulation technology) to control the motor speed. The controller of the frequency converter can perform open-loop and closed-loop control on the motor according to requirements, achieving functions such as constant torque control, constant power control, V/F curve control, and motor operation status monitoring.
In short, the frequency converter controls the motor speed by changing the power frequency and voltage to meet the requirements of different application scenarios. In industrial production, frequency converters are widely used and have important applications in fields such as elevators, cooling water pumps, ventilation fans, and wind power.