Modern Technique and Technologies 2003

REFERENCES

1. Bukreev V.G., Paraev Y.!. Adaptive regu­lators in discrete control systems of com­

plex electromechanical systems. - Tomsk: TSU pub., 2000.

2. Afanasev V.N., Komanovskiy V.B., Nosov V.R. Mathematical theory of control sys­tem design. -Moscow: V.Sh., 1998.

Alexander A. Bogdanov. Grad­uated from the Electrical Engi­neering department of Tomsk Polytechnic University in 2002. The Bachelor of Science in Electrical Engineering. A competitor for a Master's degree in science. Professional interests: motor control sys­tems, brushless DC motors.

128

Viktor G. Bukreev. Doctor of Science. A professor of Electri­cal Drive Sub-faculty in TPU. Professional interests: mathe­matical modeling of technolog­ical processes, research of the adaptive electromechanical sys­tems with incomplete informa­tion, optimal control of

Stanislav K. Sosnin. Gradu· ated from the Electrical Engi­neering department of Tomsk Polytechnic University in 1981. Equipment engineer in SOTIS Ltd. A competitor for a Candidate's degree in science. Professional interests: motor

MULTIPHASE INDUCTION MOTORS FOR A VARIABLE SPEED DRIVE

Glukhov D,M" Muravleva 0,0, Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050

Today there is a clear understanding that civilization progress is bound with new vol­ume, kinds and qualities of energy sources assimilation. Energy theory, many applied sciences are studying more economic solu­tions in power engineering. techniques and technologies. The abundance of cheap energy sources during many decades caused a new tendency to energy wasting. Energy compo· nent of cost price of agricultural and indus­trial production is greatly increasing that should stimulate the energy source saving.

Nowadays about half of all energy gener­ated in Russia falls on industrial production. At the same time about 30% of this energy is spent by turbo mechanisms: pumps, blowers and compressors. It is obvious that under modernization of process engineering pre­cisely these mechanisms are of great interest for the consumed energy saving problems.

In most cases power demand control in the above mechanisms is held by a very wasting way that is - by throttling at constant rota­tion frequency that means significant and unwarranted energy spending, unless a vari­able speed drive with adjustable shaft rota­tion frequency is used, This solution allows to decrease energy consumption up to 30% and benefit directly due to the drive type.

The purpose of the present paper is selec­

tion of the most suitable multiphase induc­tion motor for a variable speed drive.

One can use induction motor with phase number more than three in a variable speed drive. The modern level of electronics devel­

opment allows us to design the motor control system for the multiphase induction motor. Phase number increasing allows to influence the amplitude and frequency of the pulses in the inverter that has a good effect on electro­magnetic compatibility of the drive and the source under limited power of the latter. By phase number increasing we can get higher reliability of the power drive part because the induction motor is principally capable for

work in case of failure in one phase (or even in some phases) as under such conditions the rotating magnetic field persists to be pro­

duced in an induction motor. As a rule, phase number increasing leads to noise, vibration and level of interference decrease from the drive [1].

The merits of a multiphase variable speed drive make its application attractive in the fields allowing to save the consumed energy. However, the question arises as to how many phases are optimal. It is evident from the theory that their number should be odd and

Section IV: Electromechanics o� 7803-7669-2/03/ $17.00 ©2003 IEEE.

129

multiple of three. In this case even harmonics and harmonics multiple of three won't appear in harmonic spectrum. Furthermore, it is necessary to find out the' total number of phases to be placed in the standard stamp slots. Then it was decided to use two variants of phase numbers � six and nine and compare them with a three phase variant. Quality indices of induction motors have been used as criteria [2]. It should be pointed out that electromagnetic calculation has been made according to the standard methods [3]. Ther­mal calculation is based on the electrothermal

analogy with electrothermal schemes [4]. In order to get allowable thermal duty of llkW (heat resistance class of insulation F) stator core length was increased up to 12%. The obtained results are shown in TableI. Accord­ing to calculation results based on the data from Table 1 the following conclusions can be drawn.

Comparing quality indices values of mul­tiphase induction motors with reference to three phase motors one can see that such indices as power factor and efficiency are

4

3 til

.x: ..:2 III

'!l:i' -= 1

0 0 5 10 15

P, ... W

Fig. I. All advantages mentioned above make

attractive the multiphase induction motor using in a variable speed drive.

It goes without saying, the problems con­nected with multiphase induction drive are not limited by one investigation but taking

1,2 � as

�� 0,2

o ° 5 10

�i<W 15

Fig,3, (2p = 4)

Modern Technique and Technologies 2003

higher in the multiphase variants except I.lkW motor. Exceptions are starting torque values of nine phase motors and llkW motors. One can see higher thermal intensity of six-pole motors compared to four-pole motors as well. It is worth noting that marked deviations of the starting and maxi­mum torques from the necessary values are met only in some variants of multiphase induction motors. Besides, starting qualities of the induction motors can't be the key fac­tors for the drive therefore these deviations can't be considered to be the deciding factor in the problem of induction motor application in a variable speed drive.

The used material masses (copper, alumin­ium, steel) versus power in the motor are given in the graphs (Fig.1-4) as well. One can see that aluminium mass grows at power increase that is quite reasonable (Fig.l). Steel mass changes depending on machine number of poles and its power (Fig.2). Copper mass grows at power regardless of the number of poles. It is quite reasonable as wire diameter increases at power increase.

1,2 1

�0,8 iO,6 S 0,4

0,2 °

o 5 10 15

r>,nW

Fig.2.

into consideration the potential needs of its application, as well as its rare incidence and urgency of energy saving problem it is save to assume the importance of investigations in this field.

1,5 :1 .:£1 8 =§,5

o o 5 10

"'If , w

15

Fig.4. (2p = 6)

Section IV: Electromechanics 0-7803-7669-2/03/$17.00 ©2003 IEEE.

Modern Technique and Technologies 2003

Table 1

P,W 2p m SH 3 cos<l> kp

1100 4 3 0,083 0,740 0,760 2,34

6 0,080 0,751 0,761 2,52

9 0,081 0,742 0,772 2,45

6 3 0,116 0,654 0,632 1,98

6 0,111 0,656 0,634 2,06

9 0,112 0,651 0,647 1,85

3000 4 3 0,070 0,812 0,792 2,21

6 0,072 0,821 0,810 2,54

9 0,071 0,733 0,820 2,15

6 3 0,109 0,745 0,675 1,96

6 0,110 0,7�2 0,687 1,52

9 0,109 0,768 0,737 1,95

5500 4 3 0,059 0,843 0,847 2,63

6 0,058 0,845 0,855 2,83

9 0,059 0,843 0,843 2,83

6 3 0,079 0,799 0,736 2,04

6 0,076 0,840 0,757 2,64

9 0,075 0,806 0,765 1,98

11000 4 3 0,051 0,873 0,861 1,65

6 0,053 0,845 0,868 1,58

9 0,048 0,878 0,875 1,84

6 3 0,071 0,837 0,779 2,29

6 0,073 0,846 0,810 2,02

9 0,073 0,846 0,816 1,76

REFERENCES

1. An a.c. variable speed drive - the highly effective energy saving basis IV.I. Rogo­voy, L.H. Datskovsky, B.I. Abramov, B.I. Motsoheinll Electrotechnics. 1995. :NH . p.52-60.

2. D.M. Glukhov, T.V. Zharicova, 0.0. Muraleva The Design Of Induction Motor Different Dimensions At Uniform Stator

Core Cross Section. The 8th International Scientific and Practical Conference "Mod­ern Techniques and technology" Tomsk,

130

km ki mal' mst, mm' T,oC kg kg kg

2,47 4,63 0,51 11,3 0,47 75,1

2,63 4,95 0,24 75,9

2,57 4,84 0,15 79,6

2,09 3,51 0,74 19,01 0,58 83,3

2,17 3,69 0,28 87,9

2,02 3,52 0,18 94,2

2,45 ·4,92 0,78 22,7 0,94 66,1

2,63 5,31 0,57 60,6

2,46 4,93 0,38 62,5

2,07 3,57 0,95 37,7 1,04 82,1

1,87 3,15 0,48 84,5

2,16 3,82 0,37 81,1

2,86 5,96 1,22 36,1 0,71 74,1

2,97 6,21 0,72 75,9

2,96 6,21 0,45 78,8

2,33 4,51 1,66 57,6 0,74 88,2

2,73 5,29 0,68 70,7

2,35 4,52 0,26 91,6

2,49 5,14 2,36 60,6 1,12 87,5

2,34 4,93 0,69 97,1

2.75 5,69 0,76 89,4

2,51 4,99 2,91 94,1 1,18 100,1

2,45 4,78 0,66 99,3

2,34 4,47 0,43 95,8

TPU Press 2002. - p. 90-91. 3. Electrical machines design: Textbook for

univ. I I.P. Kopilov, B.K. Klokov, V.P. Morozkin. B.F. Tokarev; Ed. I.P. Kopilov.

- ard ed., rework. - M.: Higher School, 2002. - 757 p.

4. Sipailov G.A. et al. Thermal, hydraulic and aerodynamic calculations in electrical machines: Textbook for univ. on "Ele ctro­

mechanics" special. IG.A. Sipaylov, D.1. Sannikov, V.A. Zhadan. - M.: Higher School, 1989. - 239 p.

Section IV: Electromechanics 0·7803·7669·2/03/$17.00 ©2003 iEEE.