In fan application, should we run the vfd in vector control mode or v/f mode? what are the pros and cons of both the modes. what are the methods to find out the correct tunning of the motor?
What's the VFD parameters setting criteria.

It depends on the application. If it is a small fan or easy application go with V/F. As a rule V/F is going to be less accurate, lower current and less money. You can buy a vector and run it in V/F mode.

If you get into kilns with fans that are reversing and being back driven you may want vector with external braking resistors. On large fans you may not have a choice, only vector, but you may need to increase the slip to reduce current.

Most VFDs have a tuning procedure you can do or you can get motor constants from motor mfg. I think the best is to get a VFD that constantly tunes to the conditions while running, like Hitachi.

Vectors really do well below 15 hz with speed and torque control. Vectors are used in hoists where you need torque at 0 hz. The Vector senses the motor speed and adjusts the output to match the command speed. It can sense with an external device/encoder or it can sense the slip by the current waveform compared to output voltage wave form, sensorless vector.

A V/F basically just puts out the commanded frequency and does not care about changing load or slip.

If it is a centrifugal fan then it would be cube law loaded. The HP required will increase or decrease to the cube of the speed. The motor would start with no load and the load increases to 100% at 100% speed. High starting/break away torques are usually not required. As a result the motor and vfd usually do not require an added service factor.
Most of these applications do not require high accuracy speed/flow regulation so v/f is all that is needed.
If the fan is in a test facility (like a wind tunnel) and it is necessary to control the flow or pressure accurately for extended periods while measurements are taken then the vector control mode may be required.

If the speed response is not a key concern, vhz only drive is cheaper.

Thank you all for your valuable comments. can any one share the literature for detailed study? it will be helpful to me as well my organization.

When choosing drives for an application it's critical to know exactly the purpose intended. There are so many variables. A fan application although simple enough can have many factors that can complicate a motor if not correctly sized or programmed. Can you supply us with key information such as ; HP, desired speed, direct drive? Is the application air over ? How many starts and stops? Constant speed or increase and decrease?
Most vector and vfds can handle a fan application but the key is selecting and sizing a drive for long term and that will pose no unwanted spikes or heat production on both electric motor and drive.

When I was in the US Navy it was said that ships were designed with a micrometer, marked with chalk and cut with an axe. Over-design was the name of that game as it is with most fan applications. All the better to use a VFD to supply only what you need and save energy.

You will find that if you operate a centrifugal fan in vector mode (or constant torque mode for that matter) you will operate at a higher current than in variable torque V/Hz. I tried it about 20 years ago and the current was 10-20% higher in vector mode with no significant improvement in operation. Good luck.

Open-loop vector is, as much as anything, a marketing tool. Probably 90% of applications don't require it. But with the increase in microprocessor power and decrease in memory costs over the last couple of decades, it's become merely a matter of writing firmware for the drive manufacturers to include it in their standard products. The option, as others have noted, to run in V/Hz mode is almost always there. Even ABB's flagship product, the ACS800 drive, has "scalar mode" which is V/Hz.

Rule of thumb for me as to whether implementing vector control is a good idea is whether I need very high starting torque. If not, then vector probably isn't necessary and V/Hz will work fine. If precise speed control really is necessary, you can get it with V/Hz and a speed feedback device (tach, resolver or encoder) but vector gives you very good speed control (about an order of magnitude better than open-loop V/Hz) without feedback. How precise do you need to be?

Again, as others have noted, pumps and fans really don't require vector control (unless you're running a peristaltic metering pump and want to precisely control flow, for example.) And, again as others have noted, vector mode tends to be less efficient in these applications, costing you money.

If You have correct motor datas, not too long cables, one drive- one motor situation etc, the open loop vector control could be better, You can save current, the operation is more precise.
If any mistake in motor datas,(for example repaired motor) , in autotuning or changed cabling, the vector control is not the best. That case my advice V/F control.

I'm surprised by the fact that, according to many comments, vector control usually results in higher losses than V/f...
Unfortunately I don't have much exerience in applications, so it would be really interesting for me to understand this. Thanks.

@Sandro

As far as I know all variable frequency drives with vector control can also be run with just V/F control.

A drive in vector control mode has several tuning parameters to increase or decrease motor performance. With factory default parameters a drive in vector mode will have higher performance than a drive in V/F mode. Sort of like a "sport or racing" computer option in a modern automobile.

Depending on the application using vector control can use a lot more power. If you have a rapidly surging load the vector may be really struggling to keep the speed constant while a drive in V/F mode never notices the speed change. If the application has a steady mid-range speed and load or has a slow rate of change a vector and V/F may be very close in amp draw.

If you have an application where you need the vector for starting or stopping quickly but you are using a lot of current at speed you can change vector parameters to reduce the current. In some applications it is cheaper to oversize a V/F drive to get starting or stopping torque if you don't need precise speed control.

Reading all this comments about vector and V/f control of fan application makes me surprised too about the fact that most think V/f is in general better choice.

I even start thinking about simulating fan application in simulink. I think I could build a model of induction motor controlled by V/f and FOC. But I have no idea how to simulate or build a fan model connected to that. Does anyone have any idea?

I accept the fact that, in the practice, V/f is considered by many the better choice for fan loads, but I see few reasons why V/f approach could result in better efficiency.

One reason could be that, since it doesn't try to regulate anything, practically it can't oscillate due to weak stability, although oscillations may still occur (I've seen a heavily vibrating torque measurement on a fan driven by a V/f inverter).
Another could be that, while non-linear V/f curves (suitable to non-linear loads as fans) are quite common, the same is not done for the flux reference (magnitude) in vector control.
And, of course, the few parameters of a V/f control are far easier to tune than a vector scheme (which companies don't really share).

Am I wrong?

However, one interesting thing that can be done with vector control is, for slow dynamics applications, to automatically tune the flux reference to achieve a minimum loss control during the control operation. I don't think this would be possible with V/f.

I have seen every time , there is no need to operate fan in vector mode
It has to be run in v/f mode for energy saving because it will be a good result in v/f.. good luck

I have never heard of vector control mode consuming more power or being less efficient than V/Hz mode. I've also been unable to find any documentation supporting these statements. Does anyone know of any studies or published data that show vector control mode actually consumes more power than V/Hz mode and if so do they show how much more energy is consumed?

For fan applications especially I don't see how running in either mode would significantly change the power usage.