In this paper, a new topology to soft charge the dc bus capacitor is proposed. Other techniques that have beenevaluated are also introduced. The relative advantages and disadvantages are discussed. Experimental tests to show the feasibility of the proposed idea is also provided.
In this paper, a new 18-pulse topology is proposed that has two six-pulse rectifiers powered via a phase-shifting isolation transformer, while the third six-pulse rectifier is fed directly from the AC source via a matching-impedance. This idea relies on harmonic current cancellation strategy rather than the flux cancellation method and results in lower overall harmonics. It is also seen to be smaller in size and weight, and lower in cost compared to an isolation transformer. Experimental results are given to validate the concept.
This paper revisits a non regenerative active front end system that has been studied in the past but offers significant improvements to make it acceptable to the drives industry. A three-phase current injecting inductor, required in the topology, is constructed in a five limb fashion and is shown to be helpful in limiting non characteristic harmonics. Since the current injected into the split dc bus capacitor is a 360Hz ripple, it is proposed that the main dc bus capacitor be split into film capacitor for ripple current and optimally reduced electrolytic capacitor for the main energy storage requirements. Experimental results are given based on the suggested improvement and low distortion levels that were not achieved in the past have been shown to be attainable. Comparison between a standard three-limb inductor and a five-limb inductor is made to highlight the performance improvements achievable. Adoption of the topology for common dc bus applications is also proposed.
White Paper authored by Steve Petersen, concerning the use of VFDs to eliminate PLCs and other external hardware. VFDs have reached the maturity level that eliminates the need to install and program a PLC which was previously needed to make many applications function. This advancement results in overall cost and space savings. Additionally, wiring and programming complexity is reduced significantly.
White Paper authored by Mike Rucinski describing how VFDs improve Input Power Factor. Power factor is an indication of how effectively a load uses power. A high power factor indicates effective utilization of electrical power, while a low power factor indicates poor utilization. Utilities charge higher rates when power factor is low because of the extra burden imposed on the distribution system. Not only does the distribution system have to accommodate the real power being consumed, but it must also accommodate the reactive (non work producing) component flowing within the system.
White Paper authored by Christopher Jaszczolt regarding automatic energy savings features of VFDs in conveyor applications. With a drive's automatic energy savings control, industrial applications can now begin to benefit from energy savings. Not all industrial applications run their motors at rated load. Those applications that do run at rated load generally do not do so on a full time basis. One such application that can benefit from energy savings control is a conveyer.
White Paper authored by Steve Petersen, Technical Traning Services about selecting the appropriate VFD control method. Setting VFDs for the correct control method can make or break an application
Regenerative energy is present when a motor is braking or overhauling due to the load. This causes the motor to act as a generator with the energy flowing back into the VFD. The diode bridge will stop current from flowing back to the line; thus charging up the DC bus capacitors and potentially causing faults due to high DC bus voltage. In this article, we will address this challenge by comparing various solutions which use line regeneration and common DC bus arrangements.
No matter how matter-of-fact variable frequency drives have become to you, somewhere someone is using one or considering using one for the first time. Think back to when you first thought about applying one of today’s PWM based VFDs to an AC motor. Chances are you probably had a few misconceptions about their abilities and designs. In this article, we will attempt to address a few common myths of VFDs and correct some misconceptions as to their proper usage.
VFD Panels and SCCR: Short-circuit current rating (SCCR) is a number you need to heed when dealing with VFD Panels. Article written by Paul Avery. Originally published in Plant Engineering, March 2018 issue
Making use of the inputs and outputs on a VFD can prove very beneficial to an application. With all the possible wiring options and associated parameters, controls for a VFD can easily be troublesome. This article addresses in detail, the purpose and advantages of utilizing the inputs and outputs of a VFD.
There’s a lot to know behind the process of replacing a drive. On the other hand, the task can actually be quite simple when knowing what to look for and how to properly go about it. This article summarizes and provides guidance for two main scenarios most people are faced with when needing to replace a VFD.
Regenerative solutions are safe method of directing energy back onto the line. These systems can pay back the cost of the regenerative device and the variable frequency drive (VFD) operating the motor. This article compares a few of the most common regenerative solutions to present the advantages and disadvantages of each
Rev Number:
0
Language:
English
Product Group:
Inverter Drives
Product Line:
General Inverter Drives, U1000 Industrial Matrix Drive, U1000 Industrial Configured
Performing preventative maintenance on your electrical equipment before powering them back up is an important step to a smooth startup and in ensuring machine longevity. This article takes a look at 4 key maintenance tips to employ on variable frequency drives after a long period of equipment shutdown.
A user's guide to variable frequency guide terminology, this document details 50 of the most important VFD terms that VFD users should understand to more effectively specify and maintain their drive.
This article, written by Mike Grant, examines chiller applications, opportunities to increase their efficiency, how a Chiller Optimization Package (COP) retrofit solves the problem of wasted energy, and provides results from a 2015 case study of an actual 2013 COP installation at Duke Realty in Clayton, MO.
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