What is V/f control

1. What is V/f control

V/f control is the most basic control that almost every type of inverter has built-in this control method. In this mode the inverter will output an output voltage proportional to the frequency. It means that the inverter will control the frequency from 0-Fmax corresponding to 0-Vmax.

2. Application of V/F control mode

V/f control is almost the default control mode on all major inverters so it can be used for a wide variety of industrial applications. A basic application can set the inverter to run in v/f mode.

• Pump and fan control
• Lifting equipment
• Elevator
• HVAC system
• Compressed air
• …

3. Important note when installing V/f control inverter

For v/f control, we only care about parameters such as max frequency, base frequency, and max voltage of the motor. For some special applications, we can reset the v/f characteristic not in a straight line, but according to the load characteristic.

For example, for some applications that need a large starting torque, we set the inflection point so that at low frequency the voltage is higher to help the inverter start the motor better. When setting the v/f control mode, you should pay attention to install additional protection parameters such as protection time, protection current and other protection modes to help the inverter protect the motor better. .

Because v/f control is the simplest control mode, which means that the accuracy is not high, so for some applications requiring high accuracy, it is recommended to refer to closed and open vector control mode.