Over the last few years, the cost of power electricity has increased significantly. Researchers and manufacturers of electrical goods have been trying to find ways to minimize the use of power electricity while maintaining the efficiency of electrical equipment. To provide efficient energy management for today’s market, manufacturers are now turning to a technology known as variable frequency drive (VFD). VFDs are being used for various equipment ranging from small electrical appliances to the largest of mine mill drives and compressors. Choosing the right drive and the most effective configuration for specific applications requires careful analysis and preparation. Below we will list the advantages of the VFD so that you can easily make the selection process.
Advantages of VFD (Variable Frequency Drive)
VFDs can provide the below benefits:
Speed and torque control
A fundamental function of a VSD is to adjust the speed of an electric motor. If the speed of a motor can be controlled to match the process requirement, then system efficiency can be improved. In VFD, both the speed and the torque of the motor are technically adjustable.
Reduced energy consumption
Energy efficiency plays the most important role in CO2 emission reductions, accounting for up to 53% of total CO2 emission reductions. In electrical motor applications using variable frequency drive (VFD) can cut the energy consumption by as much as 85%.
Most VSDs are supplied with basic LCD or LED display keypads, with which the user can adjust parameters such as acceleration time, deceleration time, full load current, etc. This allows the user to customize the inverter for his application. Most VSDs have advanced units that could copy parameters from one unit to another. Apart from this basic function, most units available today are supplied with serial communication ports to interface with personal computers that allow users to analyze the behavior of their system.
VFDs come with communication protocols built-in or as options for a wide range of networks, such as BACnet, Metasys, Apogee, Modbus, and others to provide connection to your building automation system (BAS). Your BAS can give the VFD a signal to vary its speed according to the demand of the system. Additionally, monitors in the VFD sense conditions, status, and any problems, then send those back to the central BAS. VFD displays can be mounted on the drive or an enclosure door to give operators real-time information on system status. Problems are dealt with and logged for future reference.
Reduced maintenance cost
Maintenance costs can be lowered with the VFDs since lower operating speeds result in longer life for bearings and motors.
A soft starter for the motor is no longer required
A VFD acts like a reduced voltage starter to limit the inrush current when the motor starts. A VFD starts smoothly and eliminates high starting currents causing a disturbance in the network. Thus, an additional soft starter is not needed.
High power factor
Power factor penalties can be a part of commercial and industrial electric bills. VFDs have two types of power factors: Total power factor and displacement power factor. Utilities measure displacement power factor so a VFD can improve the power factor of a system without adding capacitors.
If there is a problem with the drive, it can be bypassed easily and the motor operated without the drive. The bypass circuit ensures the continuity of the system.
Some VFDs can control multiple motors from the same drive. This type of VFD reduces size requirements and the initial cost.
The installation of a VFD is easy. Because many pieces of equipment are factory shipped with unit-mounted VFDs that arrive pre-programmed and factory wired. Motor leads, control power for auxiliaries, and communication lines are all factory wired. The installing contractor needs only to connect the line power supply to the VFD.
The over-speed capability of VFDs can save considerable operating and investment costs. For example, the airflow through an existing fan may be increased by retrofitting a VFD to the fan motor, which will allow operation at a frequency higher than an existing rating.
Reduced GHG emissions
The electricity savings derived from the use of VFDs represent a direct reduction in CO2 emissions if the electricity is generated on-site, or an indirect reduction if the electricity is bought from the grid. Multiple types of research have reported the CO2 reductions achieved by the implementation of VFDs. The reduction in emission strongly depends on the emission factors of the specific location where the implementation of VFDs is taking place.
It has been demonstrated that VFDs lead to a reduction in the noise power from the motor and driven equipment by reducing the speed. The reduction of sound levels by varying the speed depends on the switching frequencies of the VFD. These switching frequencies are the rate at which the VFD switches on and off the DC-bus during the PWM process. Higher reductions of noise can be achieved at increased switching frequencies, especially below the base frequency. The elimination of throttles for the flow of control also reduces the level of noise generated by the system. Moreover, the soft-start capabilities of VFDs allow the speed of the pumps or fan to be ramped up to the required capacity and eliminate the start-up noise.