RF Power Transfer: Halbach vs. Dipole

[Esquilo]

Good morning, I followed this thread https://www.physicsforums.com/threads/halbach-array-arrangement-for-a-transformer.979745/, about wireless power transmission using a Halbach array and @Baluncore answers are were very satisfying. Here are two configurations, the first is a resonant dipole coil system, but in my case non-resonant, and the second configuration involves a non-resonant array of Halbach electromagnets, in which of the two cases there is a greater transmission efficiency at frequencies of the order of khz at a distance double the length of the system, and in any case forming a more directional cone of magnetic lines.

 

[berkeman]

Can you please post some sketches for what you are considering? To be honest I still don't understand your previous thread, and this one is not any clearer for me. Thanks.

 

[Esquilo]

Can you please post some sketches for what you are considering? To be honest I still don't understand your previous thread, and this one is not any clearer for me. Thanks.

good morning berkerman, yes then, the dipole coil resonant system is an excellent technology for transmitting energy wirelessly with high powers, but it is not very directive because the concentric field lines propagate in all directions, but I can use a backiron as a reflector. the halbach array is very directive but its implementation with electromagnets is complicated due to the variability of voltages. therefore I would only like to investigate which of the two solutions, with the necessary improvements, can transmit energy with greater efficiency for the same size. Attached is the dipole coil resonant system

 

[Esquilo]

as @Baluncore said, the halbach array needs many precautions, for example we cannot use AC for the arrangement, but pulsed DC with low levels of phase shifts and with the addition of high-speed diodes at the ends. so both solutions have strengths and weaknesses but I would like to understand which of the two is the best for the non-resonant WPT

 

[Esquilo]

@berkeman
What you think about this?

 

[berkeman]

To be honest, I'm still not understanding what you are trying to do.

 

[Esquilo]

To be honest, I'm still not understanding what you are trying to do.

Ok then berkerman, I would like to study wpt technology. The biggest problem is the decrease in efficiency as distance increases. Now I have two technologies, the DCRS and the halbach.

The DCRS uses the presence of the ferrite core to increase the intensity of the magnetic field but it is not very directive and therefore radiates its power in all directions to the detriment of the direction.

The halbach on the other hand is very directive but has various problems such as the use of AC and frequency. There is a patent on Google in which the magnetic cores of the halbach are joined together to make it a single solenoid.

Now I ask you, which of the two technologies (DCRS or Halbach) with the same length, current intensity and frequency, is able to transmit more efficiently at a distance double the length?

 

[Esquilo]

unfortunately I don't have access to IEEE explore, there is the only study on DCRS, the performance of DCRS is 36% at a distance equal to the length of the solenoid, while for Halbach with the same frequency and length it should double.

 

[berkeman]

What is your goal in Wireless Power Transfer? What power levels? What distances? What frequency do you want to use?

The most efficient way to focus RF power is with parabolic reflectors. Can you use that technology?

 

[renormalize]

unfortunately I don't have access to IEEE explore, there is the only study on DCRS, the performance of DCRS is 36% at a distance equal to the length of the solenoid, while for Halbach with the same frequency and length it should double.

Using Halbach Arrays for Improving Range and Efficiency of Contactless Wireless Chargers
Abstract:
This paper aims to improve the traditional wireless systems using Halbach array. Drawbacks of traditional wireless systems have been studied and it is found that one of the central problems with current wireless charging systems is its limited range and power transfer inefficiency. These greatly hamper the mobility of the system and causes inconvenience to the user. To improve this, use of Halbach arrays has been proposed which improves the directionality of the charger. A tower-like structure is proposed which can transfer power over longer distances than current wireless chargers which will remove the restriction of the charging device to stay in contact with the charger for efficient charging.

You may not have access to IEEE Explore, but this 2020 article from there seems likely to be highly relevant to your project. And it's available as a PDF for just $33 US. Why reinvent something from scratch if you can build upon previous work? What monetary value do you put on saving your own time and effort?

 

[Esquilo]

What is your goal in Wireless Power Transfer? What power levels? What distances? What frequency do you want to use?

The most efficient way to focus RF power is with parabolic reflectors. Can you use that technology?

good morning berkemann yes, the powers are very low, I only want to transfer a few mW, my aim is to study which of the two systems is the best, so my aim is educational. the dimensions I take into consideration are: solenoid length 40 cm, current intensity 10 mA, frequency from 20 to 200 khz according to studies on other systems, I would like to study how much the efficiency is equivalent to 80 cm, therefore double the length. therefore the values are the same for both but the system changes (DCRS and Halbach) unfortunately there are no formulas, such as calculating the magnetization (volume) of the magnetic core. that's all

 

[Esquilo]

@berkeman I can't use the dish because I'm not using microwaves, but inductive coupling, and therefore energy transfer through magnetic fields, perhaps the dish can serve as a backiron to convey the rear magnetic field of the DCRS

 

[Esquilo]

Using Halbach Arrays for Improving Range and Efficiency of Contactless Wireless Chargers
Abstract:
This paper aims to improve the traditional wireless systems using Halbach array. Drawbacks of traditional wireless systems have been studied and it is found that one of the central problems with current wireless charging systems is its limited range and power transfer inefficiency. These greatly hamper the mobility of the system and causes inconvenience to the user. To improve this, use of Halbach arrays has been proposed which improves the directionality of the charger. A tower-like structure is proposed which can transfer power over longer distances than current wireless chargers which will remove the restriction of the charging device to stay in contact with the charger for efficient charging.

You may not have access to IEEE Explore, but this 2020 article from there seems likely to be highly relevant to your project. And it's available as a PDF for just $33 US. Why reinvent something from scratch if you can build upon previous work? What monetary value do you put on saving your own time and effort?

hi, I tried to buy the item but I had problems paying in dollars. However, I have seen many academic articles about dipoles and coils with sparse windings, and only the various tests are listed, with the various data, but I want to know the formulas and understand, also because in the end they are just dipoles, the main problem of the DCRS is to calculate the external magnetic field