GB2291274A

GB2291274A - Permanent magnet hybrid dc motor rotor

Info

Publication number: GB2291274A
Application number: GB9413393A
Authority: GB
Inventors: Ching Chuen Chan
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-07-04
Filing date: 1994-07-04
Publication date: 1996-01-17
Anticipated expiration: 2014-07-04
Also published as: GB2291274B; GB9413393D0

Abstract

The construction of the claw type rotor consists of male members, female members and permanent magnets. The permanent magnet is mounted between a male member and a female member. The stationary dc field winding is located under the permanent magnet and held by a holder which is mounted on the end brackets. The distinct features and major advantages of the new motors are: (i) the airgap flux can be easily adjusted by controlling the direction and magnitude of dc field current, thus the required volume of permanent magnet is significantly reduced, leading to higher power density; (ii) the efficiencies over the torque-speed range can be optimized through controlling the dc field current; (iii) the speed range can be extended by field weakening; (iv) the motor can operate at constant torque regime and constant power regime; and (v) the construction is simple leading to ease of fabrication. <IMAGE>

Description

COMPLETE SPECIFICATION Improvement in Permanent Magnet Hybird Brushless DC Motor I, CHINS CHUEN CHAN, a professor of Electrical Engineering, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by it is to be performed, to be particularly described in and by the following statement: This invention relates to improvement in permanent magnet hybird brushless dc motors or permanent magnet hybird ac motors. The principles of operation of this kind of motors are already known. The magnetic flux of the motor is produced by both permanent magnet and field current, while the communication is performed by electronic switches in accordance to the position ofthe rotor. Fig. 1 shows the basic construction of the motor. The stator of the motor is similar to that of conventional ac motor.The originality lies in the novel construction ofthe claw type rotor as shown in Fig. 2, 3 and 4. The rotor consists of male members, female members and permanent magnets. The permanent magnet is mounted between a male member and a female member as shown in Fig. 2. The construction of the male member is shown in Fig. 3.

Fig. 4 shows the construction of female member holder. The field winding is located under the permanent magnets and is hold by a holder which is mounted on the endbracket. Hence the field winding is stationary and the motor is brushless.

The special features and major advantages ofthis improved motors are as follows: 1. The airgap flux consists ofthe permanent magnet flux and dc field current flux.

Thus the airgap flux can be easily adjusted in wide range by controlling the direction and magnitude ofthe dc field current, and the required volume of the permanent magnet is significantly reduced.

2. By using unique claw type rotor structure as shown in Fig. 2, the leakage flux can be minimized and the construction is compact.

3. The motor can be designed to achieve higher air-gap flux density and hence higher power density.

4. The efficiencies over the torque-speed range can be optimized through controlling the direction and magnitude ofthe dc field current. Thus leading to significant energy saving. Therefore this new motor is very suitable for electric vehicle application.

5. The torque-speed characteristic ofthe motor can be regulated in accordance with the required application through the control of the dc field current.

6. The speed range of the motor can be extended through the airgap flux weakening.

7. The motor can operate at both constant torque regime and constant power regime.

8. The construction is simple leading to ease of fabrication and low cost.

9. The power-to-weight ratio, performance-to-weight ratio, performance-to-cost ratio and overall efficiency are enhanced.

Claims

What I claim is 1. An improved permanent magnet hybird burshless dc motor having a novel construction of claw type rotor as basically shown in Fig. 2 The claw type rotor consists of male members, female members and permanent magnets. The permanent magnet is mounted between a male member and a female member. The stationary field winding is located under the permanent magnet, and is held by a holder which is mounted on the end bracket. The unique construction ofthe claw type rotor enables reduction ofthe leakage flux.
2. An improved permanent magnet hybird brushless dc motor substantially as hereinbefore described with reference to accompanying drawings.