Function of VFD in industrial automation

The function of VFD in industrial automation

VFD means variable frequency drive. These are used for controlling the speed of an AC motor and ramping a motor for a smooth startup. VFD is the tool is for greater productivity. Simply It will control the speed of an electric motor.

Controlling the speed and torque by using Pulse width modulation(PWM) of an electric motor. And it provides a continuous range of process speed control. VFDs are also known as AFD(Adjustable frequency drive), VSD(Variable speed drive), VVVF(Variable voltage variable frequency) drive.  This device will control the frequency and voltage of the input power of a motor.

By the drives, we can eliminate the wasted time and increase the overall efficiency of a process. You have an AC drive motor, then automate the process with the VFD. They can run industrial equipment, control pumps. The VFD takes direct control of the electric motor in an efficient way.

VFD control panels are a very flexible technology by this they will improve industrial operations in different ways.

VFD takes the AC power and converts it to a DC voltage Current. Then by using a capacitor, it cleans up and adjusts the voltage. VFD  uses transistors to convert the AC and send it to the monitor.

The stages that are allowed VFD to speed of the monitor controlling are,

  • Confidence in your quality assurance
  • Time management made easier

The role of the VFDs panel in IIoT

In industrial VFDs are used to convert the AC to DC power and also store the converted current if we need. In many industries, VFDs take the main role in reducing the time and resources needed to perform operations, reducing the electric costs, and increase the life of motors. VFDs allow the modulation of outgoing and incoming current.  IIoT is a main growing influence on industrial operations. These are combined with VFD capabilities, manufacturers made daily operations in a variety of ways. the benefits of VFDs in this way are,

  • Remote access
  • Multiple aces
  • Predictive maintenance
  • Real-time monitoring

What is the role of VFD in HVAC systems?

VFD for HVAC controls the heating and cooling machinery. By this VFD, systems waste less energy over time.

VFD industrial application fundamentals

In housing protection technology, the factors include high heat, moisture, or corrosive elements. The VFD panel is designed for your business and space. The capabilities of VFDs in industrial manufacturing are,

  • Visual control
  • Power switching and protection
  • Adjustable speed

Components of VFD

VFD consists of 3 main components. They are,

  • Rectifier circuit: it will convert the AC input power to DC power.
  • DC circuit unit: the DC power is filtered and stored in high power capacitors.
  • PWM inverter circuit: it will convert the intermediate DC power into Sinusoidal 3 phase AC power using the PWM technique.

Working of the VFD system

The frequency-controlled method of changing the speed of an AC motor is the best technique. In all variable speed, drive applications VFDs are used. You can control the speed of an AC motor with torque. The speed of the magnetic field and the rotor is known as the slip of the motor and torque. here motor is proportional to the slip.  The synchronous speed of the motor, that is the speed at with the stators’ magnetic field rotates is dependent on the number of poles in the stator as the frequency of the supply current.

PWM variable frequency drive

The PWM variable frequency drive system controls the speed of an AC induction motor by changing the frequency of the power supply.

The DC voltage is converted back to AC with variable voltage and frequency. this is by using integrated gate bipolar transistors or IGBT power transistors using PWM(pulse width modulation). This process is controlled by MCU(microcontroller or microprocessor). The MCU will do are, Monitor the incoming supply voltage, monitor DC link voltage, set the speed of the motor, check that the output current and voltage are within the reasonable limit.

Benefits of VFD in HVAC systems are,

  • Low motor starting current
  • Energy savings
  • Simple installation and maintenance
  • High power factor and low KVA
  • Reduced mechanical and thermal stress on motors and belts during the start

Individual benefits of VFDs are,

  • Demands lower power on start
  • Power line disturbances are shrink
  • Retain starting current in control
  • Helps in managing operating speed and acceleration
  • Limits and adjusts torque
  • Saves energy and cost


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