## Tuesday, August 17, 2021

Frequency converters explained - inverter basics

Since the advent of semiconductor technology, electronic speed variation of electric motors has taken over older systems such as Ward-Leonard groups.

This technology, which has become reliable, is still based on the same principle: from an alternative source, most of the time three-phase for elevators, the variable speed drive will recreate at the output:

A three-phase voltage variable in frequency and amplitude for AC motors.
A DC voltage variable in amplitude for DC motors.

The speed variator is essentially composed of:

a rectifier which, connected to a three-phase supply (the network), generates a DC voltage with residual ripple (the signal is not perfectly continuous). The rectifier can be of the controlled type or not, of an intermediate circuit acting mainly on the "smoothing" of the output voltage of the rectifier (improves the DC component).

The intermediate circuit can also serve as an energy dissipator when the motor becomes a generator,
an inverter which generates the power signal at variable voltage and / or frequency,
control electronics controlling (transmission and reception of signals) the rectifier, the intermediate circuit and the inverter.

In this video we take a look at variable frequency drives to understand how they work in electrical engineering and power electronics. We look at where and why to use a VFD or VSD, alternating current, direct current, single phase, three phase, frequency, rectifier, DC bus, inverter, capacitor, pwm, pulse width modulation.

Frequency converters explained - inverter basics

Since the advent of semiconductor technology, electronic speed variation of electric motors has taken over older systems such as Ward-Leonard groups.

This technology, which has become reliable, is still based on the same principle: from an alternative source, most of the time three-phase for elevators, the variable speed drive will recreate at the output:

A three-phase voltage variable in frequency and amplitude for AC motors.
A DC voltage variable in amplitude for DC motors.

The speed variator is essentially composed of:

a rectifier which, connected to a three-phase supply (the network), generates a DC voltage with residual ripple (the signal is not perfectly continuous). The rectifier can be of the controlled type or not, of an intermediate circuit acting mainly on the "smoothing" of the output voltage of the rectifier (improves the DC component).

The intermediate circuit can also serve as an energy dissipator when the motor becomes a generator,
an inverter which generates the power signal at variable voltage and / or frequency,
control electronics controlling (transmission and reception of signals) the rectifier, the intermediate circuit and the inverter.

In this video we take a look at variable frequency drives to understand how they work in electrical engineering and power electronics. We look at where and why to use a VFD or VSD, alternating current, direct current, single phase, three phase, frequency, rectifier, DC bus, inverter, capacitor, pwm, pulse width modulation.