Frequency to dc converters

United States: N. Copy to clipboard. United States. Other availability. Please see Document Availability for additional information on obtaining the full-text document. There are 2 basic types of Frequency Converters: Rotary Frequency Converters , manufactured with the use of a Motor Generator and Solid State Static Frequency Converter , manufactured with the use of semi-conductors and power stages.

The Rotary machine is brute force as opposed to the Static machine. The static unit is for non industrial applications. There are other factors to considered when deciding on a Frequency Converter. One factor is if you need the converter to also maintain power output when the utility is no longer available.

If the Frequency Converter also needs to clean up a non stable input frequency like accepting a poor frequency range on the input and produce a stable output frequency and voltage, a Dynamic Frequency Regulator should be used.

This unit allows for a very unstable utility, while producing the required output. There are several factors which will help identify which frequency conversion solution is right for your project.

Skip to content. Examples of Frequency Converters:. The frequency regulator is available from 25 — kVA. Why Choose Us? Reviews 0. Write a review. Your Name. Rating Bad Good. All it took was the maturing of the solid state device we know as the transistor. Frequency converter Components The Rectifier Because it is difficult to change the frequency of an AC sine wave while in the AC mode, the first job of a frequency converter is to convert the wave to DC.

As you will see a little later, it is relatively easy to manipulate DC in order to make it look like AC. The first component of all frequency converters is a device known as a rectifier or converter and it is shown to the left of the figure below. The rectifier circuit converts AC to DC and does so in much the same manner as those of a battery charger or arc welder.

It uses a diode bridge to limit the travel of the AC sine wave to one direction only. Three phase frequency converters accept three separate AC input phases and convert them to a single DC output.

Most three phase frequency converters can also accept single phase V or V power but, since there are only two incoming legs, the frequency converters output HP must be derated because the DC current produced is reduced proportionally. On the other hand, true single phase frequency converters those that control single phase motors utilize a single phase input and produce a DC output that is proportional to the input. There are two reasons why three phase motors are more popular than their single phase counter parts when it comes to variable speed operation.

First they offer a much wider power range. But, equally as important is their ability to begin rotation on their own. A single phase motor, on the other hand, often requires some outside intervention to begin rotation. In this case, we will limit our discussion to three phase motors used on three phase frequency converters.

The DC Bus The second component, known as the DC Bus shown in the center of the illustration is not seen and in all frequency converters because it does not contribute directly to variable frequency operation.

But, it will always be there in high quality, general purpose frequency converters those manufactured by dedicated frequency converter manufacturers. Without getting into a lot of detail, the DC Bus uses capacitors and an inductor to filter the AC "ripple" voltage from the converted DC before it enters the inverter section. It can also include filters which impede harmonic distortion that can feed back into the power source supplying the frequency converter.

Older frequency converters and some pump specific frequency converters require separate line filters to accomplish this task. The Inverter To the right of the illustration is the "guts" of the frequency converter. The inverter uses three sets of high speed switching transistors to create DC "pulses" that emulate all three phases of the AC sine wave. These pulses not only dictate the voltage of the wave but also its frequency.

The term inverter or inversion means "reversal" and simply refers to the up and down motion of the generated wave form. The modern frequency converter inverter uses a technique known as "Pulse Width Modulation" PWM to regulate voltage and frequency. We will cover this in more detail when we look at the output of the inverter. Another term you have probably run across when reading frequency converter literature or advertisements is "IGBT". The transistor which replaced the vacuum tube serves two functions in our electronic world.

It can act as an amplifier and increase a signal as it does in a radio or stereo or, it can act as a switch and simply turn a signal on and off. The IGBT is simply a modern version that provides higher switching speeds — Hz and reduced heat generation.