It can be built according to three different principles depending on the rectifier and inverter The intermediate circuit also called DC-busвЂќ or вЂњDC-link can be seen as a storage facility from which the motor is able to draw its energy via the inverter. Rectifiers made up of diodes and thyristors, to convert AC supply voltage into the DC. The rectifier is a circuit that converts the alternating voltage into the direct voltage. The supply voltage applied to the rectifier is a three-phase alternating voltage or a single-phase AC voltage with a frequency of 50 Hz or 60 Hz.

Variable frequency drive(VFD) mainly has a Rectifier, Intermediate circuit, and Inverter to convert back dc voltage into ac as shown in the block diagram. The block diagram of the variable frequency drive is shown in the below diagramДЄ Variable Frequency Drive (VFD) is a type of motor speed controller that drives an Induction motor by varying the frequency and voltage supplied to the electric motor. Here we are going to discuss working principle and block diagram of VFD.

Other names of VFD are variable speed drive, adjustable speed drive, adjustable frequency drive, AC drive. However, the basic working principles of frequency converters remain the same. VFD is a short form of a variable frequency drive also called Frequency converters, which has undergone extremely rapid changes, largely as a result of the development of microprocessor and semiconductor devices and their reduction in prices.

Futaba vfd circuit diagram