How to improve the power factor of the inverter - News - Global IC Trade Starts Here Free Join

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When the asynchronous motor starts, the slip ratio S is close to 1, when the slip is large, the power is large, and the power factor is low. When the asynchronous motor is in rated operation, the slip rate S is close to 0, the slip is small, no power is small, and the power is small. When the factor is high and the inverter starts the motor, the output frequency is low, so that the asynchronous motor slip can be guaranteed within the rated slip range, so ensure that the motor always works in the high power factor state. So it can be said that the inverter changes the output frequency and controls The asynchronous motor slip is within the rated slip range, thus ensuring the motor's operating power factor is high. If the ratio of the inverter output frequency f to the output voltage U is constant, the motor flux Φ is a constant value, that is, the field current (NIo) remains unchanged. When the motor flux Φ decreases, the excitation current (NIo) decreases, so the main way to increase the power factor of the inverter is to control the slip of the asynchronous motor. When the asynchronous motor is in the big horse, the inverter can adjust the frequency. Compared with reducing the magnetic flux Φ of the motor, it has the effect of reducing the reactive current and improving the power factor. Therefore, simply speaking, "at low frequency, the output voltage is low and the reactive current is small"
When the big horse pulls the car, the motor flux Φ can be reduced, that is, the value of the frequency-to-pressure ratio is changed, that is, at the same frequency, the voltage is appropriately lowered, the excitation current is lowered, the frequency is lowered, the voltage is reduced, the magnetic flux Φ is not lowered, and the excitation is performed. The current does not change, the reactive power does not change the frequency-to-pressure ratio, reduces the magnetic flux Φ of the motor, reduces the excitation current, reduces the reactive power, and improves the power factor.