top of page

How Many Types of Variable Frequency Drives Are There?

How Many Types of Variable Frequency Drives Are There?

Variable frequency drives (VFDs) are control systems that can vary the speed and torque output of an electric motor. They are integral components of systems that require varying motor speeds and power to efficiently support the ever-changing demands of the operation.

The importance of VFDs stems from their ability to provide significant energy savings. They allow for precise control of speed and torque, eliminating unnecessary energy consumption and reducing operating costs. Learning about how many types of variable frequency drives there are will help you determine the best option for your business needs.

Current Source Inverter Drives

Current source inverter (CSI) drives provide a constant current input. This characteristic makes them particularly robust against power quality issues such as voltage dips, making them well-suited for applications in areas with an unstable power supply. CSI drives exhibit excellent motor torque performance at low speeds and are often employed in applications requiring high start-up torque or precise torque control.

Pulse Width Modulation Drives

Pulse width modulation (PWM) drives are popular for their sophisticated control and high levels of efficiency. They operate by varying the width of the pulses in a pulse train, which effectively controls the average voltage supplied to a motor. This method of control allows the drive to adjust the motor speed and torque, making these drives highly responsive and accurate.

Voltage Source Inverter Drives

Voltage source inverter (VSI) drives are some of the most common types of variable frequency drives that businesses use for daily operations. They operate by converting the input voltage into DC and then transforming it into a variable voltage and frequency AC output. These drives are very popular in applications that require high-speed control and quick torque response.

Vector Drives

Vector drives, also known as sensorless vector drives, offer excellent motor control even at low speeds. They’re capable of adjusting the motor input’s frequency and voltage to control speed and torque, respectively. They work best with machinery that operates at varying speeds and requires high torque, like conveyors and elevators.

Direct Torque Control Drives

Direct torque control (DTC) drives offer the highest degree of control over motor speed and torque. They bypass the traditional PWM method, instead directly controlling motor variables for a faster, more accurate response. This makes DTC drives optimal for applications that demand the utmost precision and responsiveness.

As your trusted VFD distributor, Illinois Electric Works is more than capable of guiding you in selecting the appropriate VFD type to meet your specific application needs. The right VFD can significantly enhance your system’s efficiency and lifespan, making it a crucial investment for your operations.


bottom of page