Variable Frequency Drives Explained | VFD Basics - Part 2
HTML-код
- Опубликовано: 16 июн 2024
- ▶ C'mon over to realpars.com where you can learn PLC programming faster and easier than you ever thought possible!
▶ You can read the full post here
realpars.com/variable-frequen...
⌚Timestamps
00:00 - Intro
01:00 - VFD diagram
01:54 - How does an IGBT work?
03:58 - IGBT module in VFD
=============================
Welcome to Part 2 of Variable Frequency Drives Explained!
As we have learned in the previous lesson, there are many applications where in order to meet varying demands, motors need to throttle down output.
Additionally, constantly running a motor at its full speed can be costly.
A variable frequency drive is a type of controller that has the function of driving an electric motor by varying the frequency and voltage that is supplied to control its speed and power.
VFDs are widely used in both industrial and commercial applications, such as control of fans, pumps, compressors, HVACs, and even roller coasters!
It is impossible to talk about VFDs and Insulated Gate Bipolar Transistors, also known as IGBTs without understanding what Pulse Width Modulation (PWM) is.
An analog input signal can be modulated by generating variable width pulses to represent its amplitude. In a very brief summary, PWM is a way to control analog signals with a digital output.
To understand the IGBT’s function in a VFD, it is important to understand how an IGBT works singularly.
At the simplest level, an insulated gate bipolar transistor (IGBT) is a switch used to allow power to flow when it is turned on and to stop when it is turned off.
It is important to note, however, that they have the capability of switching on and off several thousand times every second!
An IGBT is a solid-state device, which means it has no moving parts.
Rather than opening and closing a physical connection, it is operated by applying a voltage to a semiconductor component, called a gate, that changes its properties to create or block an electrical path.
IGBT terminals (pins) represent the Gate, the Collector, and the Emitter.
Current flows along the conductance path composed by the Collector and the Emitter, while the Gate controls the device.
Now that we have an understanding of how our IGBTs work, let’s go back to the application of IGBTs in VFDs, and let’s represent our IGBTs as contact switches for a simpler understanding.
The top IGBTs are in the positive DC bus, and the lowers are in the negative DC bus, so when one of the top switches is closed, that motor phase and voltage then become positive.
On the other hand, when one of the lower switches is closed, that motor phase and voltage then become negative.
Therefore, by controlling the speed and sequence that those switches open and close, we can control the phases and frequency of our signal: zero, negative, or positive.
It is important to note that VFDs output signal is a PWM signal, which turns out to be a rectangular waveform.
This wave is crucial in the operation of a VFD, as it is this variable voltage and frequency that will enable the VFD to control the motor’s speed.
VFDs output signal is a PWM signal, which turns out to be a rectangular waveform. This wave is crucial in the operation of a VFD.
The control processor of a VFD contains a program that is not typically user-accessible, however, there are many parameters and settings that can be adjusted and tuned for optimal VFD operation for each application where it’s been used to meet specific motor and driven equipment specifications and needs.
The following are common adjustable parameters and settings in a VFD:
- Tunable: Proportional, Integral, Derivative (PID)
- Minimum and Maximum Speed
- Current Limit
The number of parameters varies based on the level of complexity of the VFD. They can range from 50 to over 200 parameters!
=============================
Get a RealPars pro membership: learn.realpars.com/bundles/pro
=============================
Missed our most recent videos? Watch them here:
realpars.com/omron-iiot/
realpars.com/6-axis-simulatio...
realpars.com/surveillance-system
=============================
To stay up to date with our last videos, make sure to subscribe to this RUclips channel:
bit.ly/realpars
=============================
TWEET THIS VIDEO: ctt.ac/gpIlU
=============================
Follow us on Facebook 👉 / therealpars
Follow us on Twitter 👉 / realpars
Follow us on LinkedIn 👉 / realpars
Follow us on Instagram 👉 / realparsdotcom
#RealPars #VFD #IGBT
The quality of these videos is beyond belief. So much helpful. Thanks @RealPars
Happy to hear that! Thanks a lot for your support!
Their videos are excellent lessons with a wealth of amazing information, a lot of detail and quality standard to admire.
I'm very grateful to the entire RealPars team for this excepcional content.
Congrats on mastery on the subject.
👏👏👏👏👏
Thank you so much! We truly appreciate your kind message and support
Part 1 was great! I have been waiting for this
Glad you enjoyed it!
very very very well indepth explaination,👏 with easy understanding 👍
Glad to hear that!
I TRULY LOVE REALPAARS!
Great to hear that, Brian!
I recently changed my job and this is very helpful for my adaptation in the company. Thank you a lot
Great to hear that! Best of luck at your new job!
This is really helpful thank you
Glad it was helpful!
Thank you very helpful for me.👍👍
Most welcome!
Thanks from your nice teaching we hope to share more videos with us
You're more than welcome! Thank you for your support.
I pity myself that such knowledge and development wasn't available on days when I was still productive and immersed in working
Thank you sir... Doing Great job
Most welcome!
As always a great video.
Thank you!
I watch all the videos of RealPars I'm a fan, from Brazil hugs.
Great to hear that, Alexandre!
Really helpful thank you realpars
Our pleasure!
Sir your explanation is so Amazing thank you for your service 😊
Thank you so much! It's our pleasure.
Amazing teaching
Thank you, Micheal!
Another great video
Thanks again!
Thank You!
You're welcome!
Learning from the best
Happy learning!
Very good presentation
Thank you very much!
It would be great for beginners like me by showing the parameters you used when designing the circuit
Great suggestion!
very good teaching style
Thank you very much!
Exelente explicacion
Thank you!
All video very super VFD topic amazing i am also Realpars big closely fan,from indian country state in Tamilnadu chennai.
Great to hear that, Pavunu! Thanks for your support
Welcome
All realpars teams again welcome 👌👌👌👌👌👌👌💐💐💐💐
Awesome!
Thank you!
Thanks!
You're very welcome!
Thank you very much for Teaching this video, I work Electrician
Glad it helped!
@@realpars yes friend, I will stay this channel
Very useful
Glad to hear that, Harish!
It would be really helpful if you can show how to install control wires!
Thanks for the feedback and suggestion, Silvestre! I will go ahead and pass it on to our course developers.
Thanks a lot
You're very welcome!
thank you
You're welcome!
Thankអរគុណ
Thanks 🙏🙏🙏🙏
Happy learning!
You’re the best
Thanks a lot!
It was pretty good!! Just some VFD's don't have TC in Input
Thanks for adding that, Joao!
Engineering is fascinating .
Awwwww…… I liked it better when I thought it worked on the principles of magic…. Now it makes sense….. Good explanation!
Glad it helped! Thanks for your support
Transistor has the same fonction than a contactor it just allowd the tension in 1 direction , the gate is the coil "a1 a2" , the emettor and collector is "13 and 14" in the normaly open contact :)) that all
Thank you Realpars team!!! I wonder if you have plans in adding Schneider PLC to your Schneider Online Courses? I would love to enroll in online course if this is available.
Hi Marlon,
Thanks for your comment!
We currently do not have any courses on Schneider PLC, but I will go ahead and pass this on to our course developers as a suggestion. Hopefully, this is something we can work on for future courses.
Thanks for sharing and happy learning!
I too working with Schneider plc.
In Indian market 70% occupancy is Schneider.
Hi There,
For applications where bypass VFDs required, i come across with requirements of soft motor starters in the bypass line if the vfd fails. This is understandle as in the mode of failed vfs, the inrush current in the bypass line has to be softeneded before entering motor and since there is no soft starters by default, that would be the requirement.
What are the key differences between Manual bypass and E-bypass VFDs? For both VFD types, do soft starters need to be installed within the vfd housing?
Hi Nimbo,
Thanks for your comment! Those are great questions, I will be happy to pass them along to our course developers as a topic suggestion for future video courses.
Thanks again for sharing!
it should be great if you make a video with harmonics regarding the VFD. Thanks
Great suggestion, Dan! Thank you for sharing and happy learning.
@@realpars - Btw...last week, my team spent 4 days and nights looking the reason why trip a plant room with 12-15 VFD. We got crazy . Thanks
I would also like to suggest a topic: What is the purpose of pre-charge circuit and how does it work? Thank you!
Great suggestion! I will happily pass it on to our course developers for possible future video courses. Thanks again for sharing.
@@realpars Thank you. I would expect that it is a piece of circuitry to protect the smoothing capacitor for blowing out from initial rampup voltage spike? That is my assumption but i would like to know how it works from physics standpoint.
@@Flankymanga Yes, you are correct. The resistor(s) in the pre-charge circuit slow the rate of capacitor charging so that the capacitors are not overcharged when the motor first turns on.
Great video again, I just didn't understand how T3 current transformer reads when all 3 phases passes through. It should read zero all the time I guess.
That is a great question! Although T3 is not drawn as such, T3 would typically be a three-phase current transfer, which is comprised of three interconnected single-phase transformers in a single housing, either using a single “3 phase core” or three individual toroidal cores.
Please, make it a full course. Where can I find the rest parts?
Thank you for your comment! We have the following two courses on VFD, feel free to check those out over here: www.realpars.com/courses?*=vfd
Happy learning!
Pls explain about VFD control terminal and functions
Thanks for sharing your topic suggestion, I will happily add this to the list. Happy learning!
Hello. I have a Romanian SP81sw bench lathe, it's small with an 80mm universal and it has a 0.37 kw / 380v motor. I only have a 220v network. What power should the VDF have for this motor, should I switch it to a VFD to run on 220v .Thank you!
Hi there,
Thank you for your question. To start, it's essential to ensure that your motor aligns with the specific power requirements in your local area. It's crucial to follow safe electrical connections in your region to prevent potential fire hazards and electrical problems. Adapting your motor to match the local voltage and power standards and acquiring a Variable Frequency Drive (VFD) for precise speed and current control is the safest approach. Your sales representative should assist you in sizing the appropriate VFD for your needs. Additionally, I recommend consulting a licensed electrician familiar with your area's regulations for the proper hookup. Wishing you a productive learning experience with RealPars.
Are braking resistors essential for all drives??? Especially larger rated motors???
No, but dynamic braking and other similar features can be found on most full-featured VFD packages.
@@realpars thanks for the info...
Would be great to take a course how to use VFD for PID control.
Realpars.com has two courses on PID control: learn.realpars.com/courses/how-to-configure-a-pid-controller-in-tia-portal and learn.realpars.com/courses/PID-Controller. PID control using a VFD as the final control element is essentially the same as using a control valve as the final control element. There are differences in the way VFDs behave as compared to control valves, so the tuning of the PID loop will be different. Some advanced VFDs have the capability to perform the PID control inside of the VFD electronics, which is a whole different topic. I prefer to not use that feature of a VFD unless you have a very steady application, such as an AHU fan in an HVAC system. I have noted your course suggestion and I will pass it along to our course development team. Thank you!
@@realpars thank you! Yes, using proportional valve for PID control looks quite simple and understandable in terms of connections, since this valve utilizes analog signal from AO module. To change rotation speed of the pump we need to change current frequency on VFD, that is different from valve. For professional PLC programmer it is easy task, I suppose, but for beginners like me it is not so obvious. I think, contolling pump flowrate by changing motor rotation speed is very useful task for many applications.
Thank you again for the information. Your courses are the best!
Need a video on regenerative drives
Thanks for your topic suggestion!
🙏
Does VFD change input voltage amplitude to low amplitude output voltage?
A VFD will typically maintain a constant V/f ratio in order to minimize eddy currents and hysteresis losses. Therefore, voltage changes as frequency changes. If you have a 525VAC motor operating at 50Hz, the V/f ratio is 10.5. So if a VFD is used to adjust the frequency to 20 Hz, to keep the same V/f ration, the voltage to the motor will be reduced to 210 VAC.
Wich software use to make this vedio
Please tell me
Hi Kashif,
Thanks for your comment! To answer your question, I am actually not sure about that as this is done by our graphic and animation department.
👍
what about the varying frequency component, if a ac device operating frequency is 50hz, it will perform worse at other frequencies other than its tolerance.
Motors perform best when the Volts/Frequency ratio remains constant. A motor designed for 400 VAC and50 Hz has a V/Hz ratio of 400/50 = 8. As long as that ratio is maintained at other frequencies, the motor will run efficiently/. A good VFD will require the input of the motor characteristics as parameters and use those parameters to adjust the output to the motor based on the frequency chosen to run. Using a good inverter-duty-rated motor with a VFD will help insure the longest life possible from your motor.
❤👌
🎉
Why do you only need to measure the current on 2 phases of the output to test for a ground fault
Hi Michael,
Thank you for your question. To detect a potential ground fault without causing a circuit trip, it's crucial to check for an imbalance in the electrical connection with a Ground Fault Detection (GFD) device. Testing on a single-phase Variable Frequency Drive (VFD) is essential. For a three-phase VFD, it's advisable to select any two of the three phases, as most three-phase GFD systems will monitor all three phases.
Happy learning!
Can you explain why use only 2 CT on 2 phase
Thank you for your inquiry; it's an excellent one! The suitability of this approach depends on your specific engineering and safety requirements, as well as compliance with local codes in your region. Typically, to optimize cost savings and considering your engineering needs, you aim for a current imbalance of no more than 2 out of 3 leads. In the event one current wire feed experiences a break or fault, the remaining 2 out of 3 will carry a higher current load. Consequently, the electronic circuitry will detect this imbalance and trigger a fault condition in the drive before significant damage can occur.
However, it's worth noting that many modern drives now incorporate three Current Transformers (CTs) to monitor current loads more effectively. For further information and to expand your knowledge on this topic, you can refer to the following link: en.wikipedia.org/wiki/Current_transformer
Happy learning from RealPars!
Thanks a lot@@realpars
🎉🎉🎉🎉
"How does it work with DC inverter compressor" make a video on that
Thank you for the topic suggestion, I will happily go ahead and share this with our course developers.
VFD peramiter setting all video
Where is video part 1 on description?
Hi Mehmet, you can find part 1 of this course series over here ruclips.net/video/HayryySX_po/видео.html
Happy learning!