KR20150139736A - 4 phase 8/6 Swiched Reluctance Motor for low voltage fan drive - Google Patents

Abstract

The present invention is a 4 phase 8/6 switched reluctance motor (SRM) for a low voltage fan drive which has a requirement of a cooling fan motor for a vehicle of the rated output 600 W, the torque 1.67 Nm, the velocity 2800 rpm, the total weight 1.7 kg, the current 50 A, the input voltage 12 V, and the efficiency 80%, and satisfies a condition of a stator diameter 105 mm, a rotator diameter 61 mm, a stack length 35 mm, an air gap 0.25 mm, the number of phases 4, a stator polarity arc 21°, a rotator polarity arc 23°, a shaft diameter 10 mm, and a slot area 284 mm.

Description

4 phase 8/6 SRM for low voltage fan drive {4 phase 8/6 Swiched Reluctance Motor for low voltage fan drive}

The present invention relates to a swept reluctance motor for an automotive fan drive and more particularly to a four-phase 8/6 SRM for low voltage fan drive.

Generally, small cooling fans are driven by a DC or single phase induction motor with limited variable speed range and low efficiency.

In order to improve performance and efficiency, a brushless DC motor (BDCM) is used. In this case, there is a problem that the cost is increased and heat is generated. In the case of an AC motor drive having a wide variable speed range, There is a problem that an expensive inverter must be inevitably used.

Compared to other commonly used motors, the Switched Reluctance Motor (SRM) has a simple and robust construction, low inertia, high fault tolerance, high generating torque and acceleration capability, high speed operation compatibility, simple drive circuitry and convenient switching control It has many similar advantages.

Particularly, in the case of an SRM rotor, since there is no conductor or permanent magnet, there is no cogging torque and it is easy to start.

In recent years, there has been an increasing tendency to use such a switched reluctance motor (SRM) for home appliances, air conditioners, and automobile fans [1] - [8].

[1] D. H. Lee, H. K. M. Khoi, J. W. Ahn, "Design and Analysis of High Speed 4/2 SRMs for an Air-blower ", IEEE International Symposium Industrial Electronics, pp.1242-1246, July 2010. [2] R. Krishnan: Switched Reluctance Motor Drives. CRC Press LLC, Boca Raton, Florida, 2001. [3] A. Labak, N.C. Kar, "A novel five-phase pancake shaped switched reluctance motor for hybrid electric vehicles," Vehicle Power and Propulsion Conference, 2009. VPPC '09. IEEE, vol., No., Pp. 494-499, pp. 7-10 Sept. 2009. [4] D. H. Lee, T. H. Pham and J. W. Ahn, "Design and operation characteristics of four-two pole high-speed SRM for torque ripple reduction," IEEE Trans. Ind. Electron., Vol. 60, no. 9, pp. 3637-3643, Sep. 2013. [5] K. Bie.kowski, J. Szczypior, B. Bucki, A. Biernat, A. Rogalski: Influence of Geometrical Parameters on Switched Reluctance Motor on Electromagnetic Torque. Proceedings of XVI International Conference on Electrical Machines, Krakow, 5-8 September 2004. [6] M. Tanujaya, Dong-Hee Lee, and Jin-Woo Ahn, "A Novel Switched Reluctance Motor for Neighborhoods Electric Vehicle", ECCE-Asia, June 2011. [7] Jin-Woo Ahn, Huynh Khac Minh Khoi, Dong-Hee Lee, "Design and Analysis of High Speed 4/2 SRMs for an Air-blower", 2010 IEEE International Symposium on Industrial Electronics (ISIE), vol. , no., pp.1242-1246, 4-7 July 2010. [8] Tanujaya, M, D. H. Lee, J. W. Ahn, "Characteristic analysis of a Novel 6/5 c-core type three-phase Switched Reluctance Motor" IEEE International Conference on Electrical Machines and Systems, pp. 1-6, Aug 2011. [9] T. Uematsu, R. S. Wallace "Design of a 100 Kw Switched Reluctance Motor for Electric Vehicle" IEEE Transactions on Industrial Electronics, vol. 49, no 1, pp 160-170, Feb 2002. [10] T.J.E. Miller, "Optimal Design of Switched Reluctance Motors" IEEE Transactions on Industrial Electronics, vol. 49, no 1, pp 160-170, Feb 2002. [11] K.N. Srinivas and R. Arumugam, "Finite element analysis combined circuit simulation of dynamic performance of switched reluctance motors," Electric Power Components and Systems, Vol. 30, 2002, pp1033-1045. O. Young, "Synthetic structure of industrial plastics," in Plastics, 2nd ed., Vol.3, J. Peters, Ed. New York: McGraw-Hill, 1965, pp. 15-64

In the present invention, the structure and design of three kinds of SRMs, i.e., 6/4, 12/8 and 8/6 SRM, which are suited to the requirements of the cooling fan device, are proposed, and an optimal motor design is proposed.

For this purpose, in order to evaluate the performance of these motors according to the present invention, the inductance, torque, and efficiency were compared.

In the present invention, the dimensions of the SRM are predicted by a predetermined constraint equation, and parameters are determined by selecting a predetermined value according to performance through a repetitive process of steady state. [9] - [11]

In addition, the present invention analyzes the influence of motor design parameters on motor performance, and uses finite element analysis (FEA) and transient analysis to characterize design requirements.

In addition, certain experiments have been performed to measure the inductance, torque and efficiency of the motors proposed in the present invention.

The present invention relates to a low-voltage fan drive for use with a vehicle cooling fan motor having a rated output of 600 W, a torque of 1.67 Nm, a speed of 2800 rpm, a total weight of 1.7 kg, a current of 50 A, an input voltage of 12 V, The SRM is an 8/6 SRM with a stator of 105mm, a rotor diameter of 61mm, a stack length of 35mm, a pore of 0.25mm, a number of phases of 4, a stator pole of 21 °, a rotor pole of 23 °, 284 mm. ≪ / RTI >

In the present invention, 6/4, 12/8, and 8/6 SRMs suitable for automotive cooling fan devices were designed and simulated, and simulation and experimental results show that these three types of motors can correspond to equipment requirements, It can be seen that the 8/6 SRM with four poles with eight stator poles and six rotor poles has better performance efficiency under the same conditions.

1A to 1F show the flux linkage and the magnetic flux density of the three motors proposed in the present invention.
Figures 2a, 2b, 3a, 3b and 4a, 4b are simulation and experimental profiles of three types of motor inductance.
5A is a torque profile of 6/4 SRM, FIG. 5B is a torque profile of 12/8 SRM, and FIG. 5C is a torque profile of 8/6 SRM.
Figs. 6A to 6C are dynamic model charts of 6/4 SRM, Fig. 5B is 12/8 SRM, and Fig. 5C is 8/6 SRM.
Figures 7a to 7c are experimental waveform diagrams of 6/4, 12/8 and 8/6 SRM under rated speed conditions.
8A to 8C are graphs of speed-torque curves of the three motors (6/4 SRM, 12/8 SRM, 8/6 SRM) proposed in the present invention.

Hereinafter, an SRM for driving a low-voltage fan proposed by the present invention will be described with reference to the drawings.

As is known, the SRM has some advantages in cooling fan units.

The SRM of the present invention is also designed for such a cooling fan, and examples of the requirements and dimensions of a cooling fan device for a car are the same as those in Table 1 (requirements of a car cooling fan motor).

parameter value unit Rated output 600 W talk 1.67 Nm speed 2800 RPM Total weight 1.7 Kg electric current 50 A Input voltage 12 V efficiency 80 %

The SRM can be designed in a variety of phases, such as 2-phase, 3-phase, and 4-phase, depending on the combination of stator and rotor poles.

The pole selection of the motor is one of the most important processes at the beginning of the design because the number of phases and poles is closely related to the performance of the motor such as loss, efficiency, torque ripple and noise.

In the present invention, three types of SRMs (6/4, 8/6, 12/8) are designed and evaluated for their performance.

The output equations relate to magnetic and electrical loads on bore diameter, length, velocity and mechanical power.

In general, the design of an existing motor starts with the following output equation:

[Formula 1]

는 효율이며,

는 식 2에서 정의되는 듀티 사이클(duty cycle)이고 ,

과

는 식 3과 식 4에서 계산되는 각각의 계수이다. here,

Is efficient,

Is the duty cycle defined in Equation 2,

and

Are the respective coefficients calculated in Equation 3 and Equation 4.

는 정렬 위치에서의 고정자 극의 자속 밀도이고,

는 식 5에서 정의되는 특정 전기적 부하이다.

는 구경이고,

은 고정자 극의 축 방향 길이이고,

는 회전자 속도(단위, 분당 회전수 (rpm))이다.

Is the magnetic flux density of the stator pole at the alignment position,

Is the specific electrical load defined in Equation 5.

Lt; / RTI >

Is the axial length of the stator pole,

Is the rotor speed (unit, revolutions per minute (rpm)).

[Formula 2]

는 각 상승 인덕턴스 프로파일에 대한 전류 도전 각(current conduction angle)이고,

는 고정자 위상들의 개수이고,

는 회전자의 극수이다.

Is the current conduction angle for each rising inductance profile,

Is the number of stator phases,

Is the number of poles of the rotor.

[Formula 3]

[Formula 4]

는 위상 당 정렬된 포화 인덕턴스를 나타내고

는 위상 당 정렬되었으나 비포화된 인덕턴스를 의미한다.

는 위상 당 비정렬된 인덕턴스이다.here,

Represents the saturation inductance aligned per phase

Is an inductance that is aligned per phase but is non-saturating.

Is the unaligned inductance per phase.

[Formula 5]

는 위상 당 회전 권수이고,

는 고정자 전류,

은 동시에 도전되는 위상의 갯수이다.
here,

Is the number of turns per phase,

The stator current,

Lt; / RTI > is the number of phases that are simultaneously conducting.

및 회전자 자극 호

는 다음 식 6 및 식 7의 조건을 충족하여야 한다.In order to allow the motor to start automatically,

And rotor excitation arc

Must satisfy the conditions of the following equations (6) and (7).

[Formula 6]

[Equation 7]

In the torque, the smaller the gap, the better the torque is. However, pores can usually vary depending on processing levels. Typical pore size ranges from 0.25 to 0.3 mm.

는 고정자내의 최대 자속 밀도에 따라 결정되며, 음향 노이즈를 감소시키기 위해 진동을 최소화 시키는 것도 다른 추가적인 요인으로 결정될 수 있다.Stator back iron) Thickness

Is determined by the maximum magnetic flux density in the stator and minimizing vibration to reduce acoustic noise can be determined by other additional factors.

The magnetic flux density in the stator back irons is about half of the magnetic flux density at the stator poles, but may be slightly larger.

The rotor poles are chosen to accommodate the magnetic flux density of the poles.

와 극 호의 관계가 다음 식 8과 같다면,

는 최소 0.5

의 값을 가진다. If the width of the pole

If the relationship between the polarity and the pole is given by Eq. (8)

0.5

Lt; / RTI >

[Equation 8]

Considering the mechanical robustness and the minimization of the vibration, it may be preferable to satisfy the following condition (9).

[Equation 9]

는 구조적 완결성과 작동 자속 밀도에 연관될 수 있다.Rotor back iron thickness

Can be related to structural integrity and working flux density.

The range of values to be selected should be chosen such that the inter-pole gap is larger to make the ratio between the aligned and unaligned inductances higher, while at the same time it may be desirable to make the rotor pole shorter to minimize oscillation of the rotor have.

는 다음 식 10을 만족하는 것이 바람직할 수 있다.Considering these points, consider the thickness of the rotor back iron

May preferably satisfy the following expression (10).

[Equation 10]

Depending on the requirements or constraints of the particular equipment, the main design parameters of SRMs of 6/4, 8/6 and 12/8 may be as shown in Table 2.

type 6/4 12/8 8/6 unit Stator diameter 105 105 105 mm Rotor diameter 62 62 61 mm Stack length 35 35 35 mm air gap 0.25 0.25 0.25 mm Number of phases 3 3 4 Stator pole pole 30 14 21 ° Rotor pole arc 32 16 23 ° Shaft diameter 10 10 10 mm Slot area 293 210 284 mm

As shown in Table 2, the stator diameter, stack length, pore and shaft diameter of the above three motors are the same, which is very advantageous for comparing the performance of these motors.

III. Character analysis

A. Static analysis

Generally, FEA is used for steady-state performance measurement. In the present invention, static analysis is performed for 3-phase 6/4, 12/8 SRM and 4-phase 8/6 SRM.

The SRM is typically designed to operate in the saturation region.

1A to 1F show the flux linkage and the magnetic flux density of the three motors proposed in the present invention. Figures 1a and 1b are 6/4 SRAM in three phases, Figures 1c and 1d are 12/8 SRM in three phases, and Figures 1e and 1f are SRM in 8/6 in four phases.

As can be seen from the results of Figs. 1a-1f, the flux flow passes through the excited pole when the phase current is excited and does not pass through to the other pole which is not excited.

Inductance and torque are two important characteristics of the motor.

SRM is characterized by the inductance that varies with rotor position and current.

The inductance value also affects current, torque and efficiency.

Figures 2a, 2b, 3a, 3b and 4a, 4b are simulation and experimental profiles of three types of motor inductance, the results of which are summarized in Table 3 (inductance of three types of motors).

6/4 12/8 8/6 Min. Max. Min. Max. Min. Max. simulation
[mH] 0.0278 0.200 0.0246 0.1149 0.0527 0.2514 Experiment
[mH] 0.0321 0.205 0.0303 0.1034 0.0577 0.2322

As shown in Table 3, the simulation results for specific motors were larger than the experimental results.

In SRM, the torque is created by the natural tendency of the stator poles to attract close rotor poles to the nearby rotor poles.

If the phase is excited before the rotor pole aligns with the stator poles, the rotor senses torque in the direction of rotation consistent with the motions of the motor.

Torque is the position function of the current and the rotor.

The torque profiles of the motors proposed in the present invention are shown in Figs. 5a to 5c.

5A is a torque profile of 6/4 SRM, FIG. 5B is a torque profile of 12/8 SRM, and FIG. 5C is a torque profile of 8/6 SRM.

Figs. 6A to 6C are dynamic model charts of 6/4 SRM, Fig. 5B is 12/8 SRM, and Fig. 5C is 8/6 SRM.

Table 4 compares the performance of the three motors proposed in the present invention, and each SRM of the 6/4, 12/8 and 8/6 types is designed to have an average torque of 1.74 Nm, 1.72 Nm and 1.74 Nm.

type 6/4 12/8 8/6 unit External Power 512.52 505.49 507.94 W Average torque 1.74 1.72 1.74 Nm speed 2800 2800 2800 rpm electric current 50 50 50 A Input voltage 12 12 12 V efficiency 88.5 85.3 85.3 %

IV. Experiment result

A driving performance

The experimental waveforms of 6/4, 12/8 and 8/6 SRM at the rated speed condition (2800 rpm) are shown in Figs. 7a to 7c.

The load torque was maintained at a rated speed of 1.7 Nmh.

8A to 8C are graphs of speed-torque curves of the three motors (6/4 SRM, 12/8 SRM, 8/6 SRM) proposed in the present invention. 8A to 8C, the relationship between the efficiency and the speed of the motor can be known.

The results of Figures 8a-8c are summarized in Table 5 below. As can be seen in Table 5, it can be seen that the 8/6 SRM has the maximum efficiency under the same conditions.

type

parameter 6/4 12/8 8/6 unit simulation 88.5 85.3 85.3 % Experiment 81.0 81.4 85.2 %

As described above, according to the present invention, 6/4, 12/8, and 8/6 SRMs suitable for a car cooling fan device were designed and simulated, and simulation and experimental results show that these three types of motors It can be seen that the 8/6 SRM of four phases with 8 poles of the stator and 6 poles of the rotor has a better performance efficiency under the same conditions.

Claims (1)

The requirements of the automotive cooling fan motor are 4-phase 8/8-phase motor for low-voltage fan drive with rated output 600W, 1.67Nm torque, 2800rpm speed, total weight 1.7kg, current 50A, input voltage 12V, efficiency 80% 6 As an SRM,
The rotor having a stator diameter of 105 mm, a rotor diameter of 61 mm, a stack length of 35 mm, a pore of 0.25 mm, a number of phases of 4, a stator pole of 21 °, a rotor pole of 23 °, a shaft diameter of 10 mm, and a slot area of 284 mm 4-phase 8/6 SRM for low-voltage fan drive.

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