What Is A Variable Frequency Drive

How Is VFD Defined?

Variable Frequency Drive, also known as adjustable frequency drive or adjustable speed drive is a motor controller that has the ability to vary the frequency and the voltage which come to the motor and with that to enable driving the motor.

How The Variable Frequency Drive Works?

The variable frequency drive is consisted of to main components: rectifier and inverter, and additional parts such as transformer and battery.

In the VFD the rectifier is the part that is used for converting the AC power that comes from the power source, to DC power. After the conversion of AC power to DC power, the inverter converts the received DC power to the desired frequency AC power.

The third part, the transformer adjusts the voltage and isolates the electric output and input circuits. During the conversions, a battery is used for compensating the lost energy inside the drive circuit which is located inside the variable frequency drive.

Where is Variable Frequency Drive Used?

VFD is used in a variety of applications. It can be used from small appliances up to massive-in-size mine mill drives. This motor controller is also used in wide range of compressors.

The use of VFD in the recent years has noted significant growth as a result of the improvements that were made in it's design and performance and the reduction of the price. The improvement that were made in the design and the performance capacity of the VFD, were made through:

• advancements in the semiconductor switching devices;
• improvements in the techniques for control and simulation;
• changes in the software and hardware vital for the control.

Benefits Of The Use Of Variable Frequency Drive

• Energy Saving – The use of VFD in applications where motors with mixed speed are used, is proven as energy saving practice. This means that, by adjusting the speed of the motor with the use of this controller, the applications can be performed with lower amount of energy.
• Control performance – Besides the improvements and benefits in the usage of energy, the variable frequency drive can improve the overall quality of the industrial and commercial applications. This is achieved thanks to the ability of this controller to control the flow, the speed, the pressure and the temperature during the applications.