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designing of a permanent magnet and directly driven synchronous generator for low speed turbines/sistemos su nuolatiniu magnetu ir tiesiogiai sujungto generatoriaus su letaeige turbina projektavimas.

by:Newland     2020-02-28
Introduction: Micro-hydraulic power plants are being used in foreign residential areas [1].
In such factories, turbines and generators are coupled with each other through inventions such as belt pulses and gear mechanisms;
Power generation can be generated after the event [2].
The increase in the speed difference between the turbine and the generator increases the cost and complexity of the system and reduces the feasibility and efficiency.
Therefore, the producer suggested that the turbine must be fixed directly [2, 3, 5]. Michell-
The Banki turbine is the first choice for small rivers, driving the generator through the pulley until 100 KW power, more than 100 KW power, the generator is driven by the turbinevia gearbox [1]3].
In this study, a generator constructed by a permanent magnet and driven directly by a Banki turbine was designed, not by an external excitation.
Since the designed permanent magnet generator can eliminate the coupling design of the contemporary system, it can reduce the setup and operating costs.
Based on the geographical features of the site, the drop and flow, and the specific speed values of the water, determine the best choice for turbine types in any operating place.
At the small waterfall (between 2-60 meters long)
Large water flow, from 2 kWs to 2000 00kws, is using a Kaplan-type turbine with a specific speed of more than 450 rpm [1, 6].
The rotational speed range of the hybrid turbine is 45550 rpm at 2-
600 long mid waterfall and 2-
600000 species of plants [1, 6].
The speed range of the Pelton turbine is 2-30 rpm;
They\'re in 60-
Large cloth and 2-1000 long-
100000 kWs power plant [6].
The Banki turbine is made up of gears and water outlets.
The water comes from the hanger mouth, penetrates into the gear that is shaped into wings, it passes through the inner space, enters the wings from the hoop of the gear, and so on, a secondary force that occurs to release the turbine.
It is used for up to 200 waterfalls and 9 [m. sup. 3]
Water flow and water flow of small hydropower stations [6].
Banki turbines can be used in the case of small water flow, which can achieve higher efficiency.
For low speed/high torque, permanent magnet motors are used in many industrial applications.
This means that the permanent magnet synchronous motor can be used instead of the asynchronous motor system connected to the gearbox at a low speed drive.
Since there is no gearbox cost for the direct drive system, the maintenance cost is not high, the efficiency is high, the noise emission is low, and the opening system is light [9, 13].
Although connecting the motor to a drive machining system without a gearbox reduces the cost and the volume of the combined unit contains the motor, the gearbox and other equipment, it also improves the reliability of the system.
In recent studies, an electric motor with high torque at low speed has been designed [3, 4, 7].
The loss in the materials and methods used in the design the loss in the motor is the ferrite and core loss that occurs in the active magnetic components and the Cu loss in the machine [Circuit]10, 11].
Neodmiyum-Iron-Boron(Nd-Fe-B)
Magnet quietly brings added value to the improvement of the permanent Magnet structure synchronous motor [8].
SmCo magnets focus on the development of NdFeB magnets [10].
High-energy magnets like NdFeB have a relatively large impact on machine performance [5].
Therefore, in this design, NdFeBand SmCo with good magnetic properties and low cost is selected.
As a design parameter, the magnetic flux density is calculated according to the formula.
1 and electric power (emf)
The air gap is from (2): B = [nabla]x A, (1)[
Mathematical expressions that cannot be reproduced in ASCII](2)
Where A is the magnetic vector potential; [nabla]
Is the flux density curl of the magnetic vector potential of the air gap? 15]; [N. sub. ph]
Number of series windings per phase; [k. sub. w]
Distribution coefficient of winding; [K. sub. n]
Is the total harmonic number; [[PHI]. sub. n]
Average traffic per pole.
The induced voltage in the machine with P pole number and continuous winding is (3)E = 4. 44f[[PHI]. sub. n][N. sub. ph]X [k. sub. w]. (3)
The output power of the machine is proportional to the magnet volume (4)[P. sub. max]= [[pi]. sup. 2]/ 2 * [xi]/[k. sub. f]*[k. sub. ad]*(1+[epsilon])* f * [B. sub. r]* [H. sub. C]*[V. sub. M], (4)where [k. sub. f]
Is the density of magnetic flux; [k. sub. ad]
Is eternal; [epsilon]
Is the relationship of no-
Load; magnetic force and voltage; f is frequency; [B. sub. r]
Is the density of permanent magnetic flux; [H. sub. c]
It is force; [V. sub. pm]
Magnet volume; [xi]
Is the magnet constant?
See the output power of the motor (5)[P. sub. R]= [eta]m / t [[integral]. sup. T. sub. 0][I. sub. pk]
Phase Current and its peak value; [eta]
M is the number of phases and T is the period.
Equation 6 of the standard permanent magnet motor [gives the peak value of the air gap phase EMFE. sub. PK]= [K. sub. e]*[N. sub. t]*[B. sub. g]*f / p[[lambda]. sub. 0][D. sub. 0][l. sub. e], (6)where [K. sub. e]
Is it the EMF factor [? N. sub. t]
Number of turns per stage ,[B. sub. g]
The air gap flux density, f is the frequency, p is the pole pair ,[D. sub. o]
The outer diameter of the machine is the effective length of the machine.
The peak of phase current is (7)[I. sub. pk]= 1 / 1+[K. sub. [PHI]][K. sub. i]A[pi][[lambda]. sub. o][D. sub. o]/ 2[m. sub. 1][N. sub. t](7)where;
A is the total electric load ,[K. sub. f]
It is the ratio of the rotor electric load to the stator load.
The output power of the standard permanent magnet motor is [D. sup. 2]
L equations such (8)[P. sub. R]= m / [m. sub. 1][pi]/ 2[K. sub. e][K. sub. i][K. sub. p][eta][B. sub. g]A f / p[[lambda]. sup. 2. sub. 0][D. sup. 2. sub. O][l. sub. e](8)
In this study, a permanent magnet synchronous generator was designed, which is considered to be a generator for a turbine with low water level descent.
I. Basic parameters such as power and size.
Achieved;
Then the magnetic static analysis was carried out. [16].
The 3D model of the designed generator can be seen in the picture1.
For the convenience of analysis, even symmetric boundary conditions are used;
Subsequently, the analysis was obtained in a reasonable form in a short period of time.
Stator slots as shown in the figure
2 is designed to reduce rotor positioning torque when reclining.
The inclination angle of the stator slot is calculated to minimize the positioning torque.
Table 1 shows the parameters and values obtained from the analysis results. [
Figure 1 slightly][
Figure 2:
The 6nm positioning torque will affect the rotor at the rotational speed.
It is inferred that the positioning moment is within an acceptable boundary in the designed motor. Fig.
Figure 3 shows the positioning moment curve of the machine.
As can be seen from the figure
4. The peak positioning moment is limited to about 7 Nm. [
Figure 3 slightly]
The speed and output power of the designed generator are shown in Fig. 4.
In the simulation, the rotation speed of the generator is used as a variable;
Enter the parameters to be calculated as the output power.
When the speed interval changes between 0 and 550 rpm, it has been observed that the output power changes between 0 and 11 KW.
G raphics shown in Figure 1 verified 4 KW output power at 300 rpm5. [
Figure 4 slightly]
In this paper, the finite element method is used to analyze the designed permanent magnet generator.
The air gap magnetic density, its waveform, total magnetic flux and induced potential values are calculated by finite element method.
Since the slot structure and magnetic saturation make it complicated to calculate the air gap, 3D finite element analysis has been performed.
The results drawn through the contour line in the air gap can be seen in Figure 15-6.
The peak magnetic flux density at the gap is about 1.
According to Figure 0 t. 5. From Fig.
6. It can be seen that the calculated air gap flux density is about 1. 25 T.
This peak can be used to calculate the voltage when the generator is in analytical design [14]. [
Figure 5 Slightly][
Figure 6 slightly]
In order to calculate the induction generator voltage, the flux density value at the air gap must be known.
Therefore, several simulations were carried out through Maxwell 3D and Rmxprt, comparing the values found in the air gap.
It is inferred that the flux density given
5 and 6 are very closed values for each other.
The designed generator has been transferred to the 3D model for magnetic static analysis.
Figure 1 shows the generator structure and grid network for finite element solution. 7. [
Figure 7 Slightly]
The established model is analyzed by finite element method.
In the analysis, grid tightness was added in sensitive solution.
The entire model of the generator and the distribution of the magnetic flux density can be shown in Figure 18. [
Figure 8:
It can be seen that in this model, the magnetic flux density is left in the tight part of the stator slot (Fig. 9).
The flux density is within an acceptable range.
The maximum saturation obtained is 1.
7t of the designed machine, this value can be seen in the closest part of the stator slot. [
Figure 9 omittedFrom Fig.
10, for the radial flux permanent magnet generator, the induced potential curve of each phase can be seen.
As shown in the figure.
10, the induced voltage wave provides a stable signal for the generator running at 300 rpm. Fig.
11 shows the change of phase current when the generator is running at the rated speed.
If the generator takes over the load, the peak of phase current is out of order. [
Figure 10 slightly][
Figure 11 omitted]
Conclusion in this study, a radial flux permanent magnet generator was designed for low-speed turbines by analysis and computer-aided finite element method.
The designed generator has been described in detail through 3D static and magnetic analysis, and it has been seen that it will be used as a direct drive machine for low speed turbines.
In this design, a certainvalue should be a constant speed, and the magnetic parameters have been calculated for the obtained generator model, and these values have been visualized.
In the analysis, the load given in Table 1 should be connected to the terminal of the generator.
The results obtained under this load are the basis of the evaluation.
It is observed that the ratio of the magnetic step distance to the polar step distance of the designed magnetic flux generator is affected when it drops to the positioning torque.
In the case of transcendence, geometric structure
Design the length of the machine)
The efficiency is obtained by a normal generator, not redundant. References [1. ]Adhau S. P.
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