Variable frequency drives are also known as adjustable speed drives or adjustable frequency drives and these pieces of equipment are a specific type of motor controllers that are used to drive electric motors by varying the frequency and voltage supplied to the electric motors.

Components

The main components which all variable frequency drives consist of are an inverter and a rectifier as well as some additional parts such as battery and transformer.

The rectifier is the part that is used for converting the AC power that comes from the power source, to DC power. After this conversion, the inverter converts the received DC power to the desired frequency AC power. The transformer is a significant component of variable frequency drives which adjusts the voltage and isolates the electric output and input circuits. Throughout all these conversions, a battery is used to compensate for the lost energy inside the drive circuit located in the variable frequency drive.

Usage

From small appliances to massive-in-size mine mill drives, variable frequency drives can be used in various applications. Moreover, these motor controllers can also be used in a wide range of compressors. As a result of their design and performance improvements as well as their lower prices, in the past few years the use of these motor controllers has been on the rise. Their improvements were made through:

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

If it is still unclear to you why variable frequency drives are so useful, take a look at their benefits:

• Energy Saving – The use of variable frequency drives in applications where motors with mixed speed are used has been proven as an energy saving practice. Therefore, by adjusting the speed of the motor with the help of this controller, the applications can be performed with lower amount of energy. The energy saving benefit is especially high when used for pump applications. However, there are other applications with a big potential for energy saving. After you buy them, these AC motor controllers can save you energy for many years and can be a very good cost-effective solution in the long run.

• Control performance – The improved performance and energy saving feature are not the only benefits of these motor controllers. Thanks to their ability to control the speed, flow, pressure and temperature during the applications, they can also improve the overall quality of the commercial and industrial applications.