The carrier frequency of a frequency converter refers to the frequency at which a lower signal frequency is modulated to a relatively higher frequency during signal transmission. This higher frequency modulated by the lower frequency is called the carrier frequency, also known as the base frequency.
The effect of carrier frequency on frequency converter (1) The higher the operating frequency, the larger the duty cycle of the voltage wave and the smaller the higher harmonic components of the current. That is, the higher the carrier frequency, the better the smoothness of the current waveform.
(2) The higher the carrier frequency, the smaller the current that the inverter can output;
(3) The higher the carrier frequency, the smaller the capacitive reactance of the wiring capacitor (because Xc=1/2πfC), and the greater the leakage current caused by the high-frequency pulse.
(4) The higher the carrier frequency, the greater the loss of the inverter and the lower the output power. If the ambient temperature is high, the dead zone of the two inverter tubes in the upper and lower parts of the inverter bridge during the alternating conduction process will be smaller, which may lead to a short circuit in the bridge arm and damage the inverter in severe cases.
The effect of carrier frequency on motor (1) The higher the carrier frequency, the lower the noise of the motor.
(2) The higher the carrier frequency, the less heat the motor generates.
The carrier frequency of the OKE inverter is pre-set at the factory. Under normal circumstances, users do not need to change this parameter.
When users use more than the default carrier frequency, they need to reduce the usage rate. For every additional 1K carrier frequency, the rate will be reduced by 20%.
P01.14 | Carrier frequency setting | 1.0～15.0kHz | Model settings |
Advantages of high carrier frequency: more ideal current waveform, fewer current harmonics, and less motor noise;
Disadvantages of high carrier frequency: Increased switching losses, increased inverter temperature rise, and impact on inverter output capability. Under high carrier frequency, the inverter needs to be derated. At the same time, the inverter leakage current increases, leading to increased electromagnetic interference to the outside world.
Using a low carrier frequency will have the opposite effect. An excessively low carrier frequency will cause instability in low-frequency operation, reduced torque, or even oscillation.
