RESEARCH OF PERMANENT MAGNET GENERATOR WITH COMPENSATED REACTANCE WINDINGS ABSTRACT In this article, a patented “bifilar” coil (BC) type permanent magnet generator (PMG) is constructed for scientific research and comparison with other technologies. The features, working principle and elements of the BCPMG are analyzed. The BCPMG is developed from the iron-cored “bifilar” coil topology (1) in an attempt to overcome the problems with current rotary type generators, which have so far been dominant on the market. One of the problems is armature reactance , which is usually bigger than resistance . The circumstance creates difficulties for designers and operators of the generator. That is why patented technology is offered to partially remove or absolutely neglect the reactance of the machine. Drawings of the PMG parts and assembly are added. A finite element magnetic model (FEMM) is presented and analyzed. An experimental analysis of the PMG characteristics, such as no-load losses and EMF vs. speed, loaded voltage drop, power output and efficiency vs. load current at different speeds. INTRODUCTION Relevance of the topic. Classic generators are based on electrical induction or electric currents and magnetic fields. Each electric machine that uses permanent magnets, can act as a generator or motor. One of existent problems of manufactured electric generators is that the coil reactance , the most common, is greater than the active coil resistance . This fact creates difficulties for designers and operators of generators. The proposed generator or motor should partially or completely compensate reactance. The object: Patented PMG prototype with reactance compensated winding. The aim: Research the type of patented PMG, which is claimed to have significant internal circuit reactance compensation by winding special coils and construction of before unseen machine. Methods. Design aspects are evaluated with the help of literature, scientific articles and patent analysis of existent PMG technologies. Prototype is designed and drawings are made with SolidWorks. Magnetic analysis is conducted with FEMM (2D) and EMS add-on for SolidWorks (3D). Electrical schematics are drawn with EAGLE CAD. Experiments are conducted in Klaipeda university LAB facilities. Achieved data is analyzed and characteristics plotted with MS Excel.
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RESEARCH OF PERMANENT MAGNET
GENERATOR WITH COMPENSATED
REACTANCE WINDINGS
ABSTRACT
In this article, a patented “bifilar” coil (BC) type permanent magnet generator (PMG) is
constructed for scientific research and comparison with other technologies. The features, working
principle and elements of the BCPMG are analyzed.
The BCPMG is developed from the iron-cored “bifilar” coil topology (1) in an attempt to
overcome the problems with current rotary type generators, which have so far been dominant on the
market. One of the problems is armature reactance , which is usually bigger than resistance .
The circumstance creates difficulties for designers and operators of the generator. That is why
patented technology is offered to partially remove or absolutely neglect the reactance of the
machine. Drawings of the PMG parts and assembly are added. A finite element magnetic model
(FEMM) is presented and analyzed. An experimental analysis of the PMG characteristics, such as
no-load losses and EMF vs. speed, loaded voltage drop, power output and efficiency vs. load
current at different speeds.
INTRODUCTION
Relevance of the topic. Classic generators are based on electrical induction or electric
currents and magnetic fields. Each electric machine that uses permanent magnets, can act as a
generator or motor. One of existent problems of manufactured electric generators is that the coil
reactance , the most common, is greater than the active coil resistance . This fact creates
difficulties for designers and operators of generators. The proposed generator or motor should
partially or completely compensate reactance.
The object: Patented PMG prototype with reactance compensated winding.
The aim: Research the type of patented PMG, which is claimed to have significant internal
circuit reactance compensation by winding special coils and construction of before unseen machine.
Methods. Design aspects are evaluated with the help of literature, scientific articles and patent
analysis of existent PMG technologies. Prototype is designed and drawings are made with
SolidWorks. Magnetic analysis is conducted with FEMM (2D) and EMS add-on for SolidWorks
(3D). Electrical schematics are drawn with EAGLE CAD. Experiments are conducted in Klaipeda
university LAB facilities. Achieved data is analyzed and characteristics plotted with MS Excel.
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1. DESIGN ASPECTS OF PMG
1.1. Fig. 3D isometric view of PMG construction
1.1. Finite element magnetic model
A half of this PMG construction is unfolded into linear type and modeled in 2D
environment. Down below cores are shown as poles with wound coils around them and the magnets
from both sides surface mounted on iron plate. Another half of the generator is eliminated, because
it is impossible to have a full model in 2D environment.
1.2. Fig. Magnetic circuit flux lines of PMG topology with double magnets.
This topology has 4 magnets for 3 stator rods or 2 pole pairs for 3 phases. The original plan
was to put 10 permanents magnets on each of the four parts of the rotor. The reason is due to little
magnetic field interacting, if every second magnet from top and bottom is eliminated, there is only
half area left for the other magnet pole, while the first one covers a full area, which causes high
cogging torques while spinning and only half of the flux from magnets is used. This problem has
been fixed by mounting 20 permanent magnets on each of the four parts of the rotor. With the
configuration, while the one coil faces one pole (north for example), the following two coils face 3
quarters of a south pole and a quarter of a north pole so the magnetic force of the coil A is equal to
the magnetic force of the coils BC.
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1.3. Fig. Magnetic circuit flux lines of PMG topology with fewer magnets.
A magnetic transition between rotor and stator is shown below in steps.
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Step n
1.4. Fig. Magnetic circuit flux lines of PMG while moving through steps.
A 3D finite element analysis is made to show relationship between magnets and stator rods.
For that task a 1/5 segment of the generator is cut out and shown below.
1 5
1 1 1
3
3
3
2
2
2
5
1.5. Fig. 1/5 segment of patented PMG active material, magnetic flux density vector plot (front
view)
1) Magnets;
2) Windings;
3) Ferromagnetic cores;
4) Magnetic flux lines with direction arrow;
5) Iron or steel non-laminated core;
6) Rotor supporting part (non-magnetic);
7) Shaft.
1.6. Fig. 1/5 segment of patented PMG active material, magnetic flux density vector plot (top view)
1.7. Fig. Magnetic flux density continuous fringe plot on several sections: A – cross section of
magnet array, B – cross section of coils
1.8. Fig. Magnetic flux density continuous fringe plot on several sections: C – axial section of core
phase C, D – axial section of core phase A
Further a 3 phase current is applied to show the relationship between wound stator and magnets.
A
B
D C
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1.9. Fig. 1/5 segment of patented PMG active material magnetic flux density with applied 3 phase
current 10A RMS
1.10. Fig. Magnetic flux density with applied 3 phase current 10A RMS axial section of first wound
rod (right side view)
1.11. Fig. Magnetic flux density with applied 3 phase current 10A RMS cross section of first array
of magnets (front view)
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2. EXPERIMENTAL RESEARCH OF PMG
2.1. Measurement equipment and specifications
2.1. Table. Measurement device
Measurement
device Model AC/DC Max scale
Tolerance
class Use
Ampermeter M1500T3
1984 DC 1,5
DC motor
armature
Voltmeter M1600
1979 DC 1,5
DC motor
armature
Multimeter Agilent
U1241A AC/DC 1000V
PMG voltage and
frequency
Multimeter Mastech
MS8222H AC/DC 10A PMG current
2.2. Table. Parameters of driving machines
Driving machine Model Power Gearbox Speed Year
DC motor П-42 7,2
kW No 2800 rpm 1976
Induction motor
– Lathe
Красный
Пролетарий
1K62
10 kW Yes
(Multiple)
1450 rpm
(50, 63, 80, 100, 125, 160, 200,
250, 315, 400) 500, 630
1971
2.2. Analysis of the results
2.2.1. No-load data analysis
The No Load results of the experiment provide the information of power losses in
mechanical and magnetic (eddy currents) parts, the size of EMF induced.