AU2149401A

AU2149401A - Driving device with two driving motors of different capacity for a vessel

Info

Publication number: AU2149401A
Application number: AU21494/01A
Authority: AU
Inventors: Christian Meyer; Ingo Schuering; Peter Wengler
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1999-11-30
Filing date: 2000-10-20
Publication date: 2001-06-25
Also published as: CN1402679A; AR026635A1; ATE247580T1; JP2003517253A; KR100687964B1; KR20020063580A; EP1233904A1; BR0015973A; EP1233904B1; ZA200204286B; PT1233904E; ES2204731T3; WO2001044046A1; DE19958783A1; DE50003392D1

Description

1999 P 04206 WO Description Propulsion device, with two drive motors of different power, for a ship 5 The invention lies in the field of the drives of electrically driven vehicles and is used for the structural and design embodiment of a propulsion device for a ship which has, essentially, two operating ranges 10 for a propeller, which has direct electric motor drive via a drive shaft, namely a first drive range for propeller rotational speeds up to approximately 30% of the rated rotational speed and a second operating range for the propeller rotational speeds extending beyond 15 this speed up to the rated rotational speed. A known propulsion device of this type is used for the propulsion of naval ships such as submarines and can also be employed in the case of surface ships. The 20 propulsion device has a synchronous motor with a rotor, which is excited by permanent magnets, and with a distributed multiphase stator winding in which each phase winding is supplied by its own static converter. This multiphase alternating current motor with static 25 converter supply is directly coupled - if appropriate by means of a coupling - to the drive shaft carrying the propeller. The rotational speed of the motor can be steplessly adjusted over the complete power range, a submarine drive being essentially operated in a lower 30 rotational speed range up to 30% of the rated rotational speed for minimum noise-limiting vessel speed and cruising speed and in an upper rotational speed range of approximately 50 to 100% of the rated rotational speed for high vessel speed. The operation 1999 P 04206 WO - 2 in the lower rotational speed range is the main type of operation. (Journal "Jahrbuch der schiffsbautechnischen Gesellschaft 81" (1987, Pages 221 to 227 and 229 to 234) . In this arrangement, the drive energy for the 5 motor is taken from an electrical energy reservoir (battery) and/or from an electrical energy generator, for example a diesel-generator set or a fuel cell installation. - In order to optimize the efficiency of such a propulsion device, individual winding parts of 10 the multiphase stator winding configuration can be connected in series or parallel; this has, inter alia, the result that the overall efficiency of the propulsion device is higher down to the lowest permissible continuous rotational speed than it is in L5 the case of conventional drives. At low rotational speeds, the efficiency only lies slightly below the optimum value at high rotational speed to an insubstantial extent. O For surface ships, in the form of large container transport ships for example, a propulsion device is known, per se, in which an electric motor of low power is provided in addition to a diesel engine of high power. The motor and the engine are connected in series .5 to the drive shaft of the propeller. The electric motor, which is designated as a "booster drive" and has a rated power of between 2 and 15 MW, this rated power being at least 10% of the rated power of the diesel engine, is associated with the diesel engine for 0 support purposes in order to compensate for disadvantages in special travel situations, for example in the starting phase, in the acceleration phase in the medium-speed range and in the full-load phase. These disadvantages are characteristic of the diesel engine 1999 P 04206 WO - 3 in these operating phases (brochure "Electrical Booster Drives" of Siemens AG, Pages 1 to 9; US 4417878 A, DE 4432483 Al). 5 On the basis of a propulsion device with the features of the preamble to claim 1, the invention is based on the object of configuring the propulsion device in such a way that a better efficiency can be achieved, particularly in the lower rotational speed range. 10 In order to achieve this object, provision is made according to the invention for a second electric motor, which is likewise configured as a multiphase alternating current motor with static converter supply, L5 to be arranged on the drive shaft and for the two electric motors to differ from one another in their rated power in such a way that the power ratio is greater than/equal to 20:1. 0 In a propulsion device configured according to the invention, account is taken of the fact that a drive power of less than 1/20 of the maximum drive power is all that is necessary for the lower rotational speed range up to approximately 30% of the rated rotational '5 speed. A drive motor of lower power is correspondingly provided specifically for this rotational speed range; this drive motor must satisfy all the mechanical, electrical and acoustic boundary conditions which are characteristic of a naval ship, of the type being 0 discussed, when operating at low vessel speed. The higher power drive motor, on the other hand, is designed for high vessel speed, during which the extreme structure-carried noise requirements, which exist for slow vessel speed, no longer apply. The 1999 P 04206 WO -4 increased acoustic and electrical requirements are therefore only realized in the case of a small drive motor, whereas the large drive motor can satisfy lower requirements. The overall efficiency is improved in the 5 lower power range by optimizing the small drive motor. This advantage becomes more important as the power requirements with respect to high vessel speed become greater when, therefore, power ratios between the two drive motors of more than 50:1 have to be realized, 10 i.e. 8 MW/150 kW for example. A synchronous motor with permanent magnet excitation rotor can, in particular, be considered for the lower power drive motor. It is, however, also possible to L5 employ a brushless salient pole machine excited by direct current. - Because the higher power drive motor have to satisfy lower requirements than the lower power drive motor, it can also be configured as an asynchronous motor. A synchronous motor with non ?O salient pole rotor or salient-pole rotor excited by direct current could satisfy increased requirements whereas, in the case of the maximum requirements, a synchronous motor with permanent magnet excitation rotor can also be considered. !5 In a propulsion device configured according to the invention, the two drive motors can form a structural unit, which is compact and which can be manufactured and assembled at favorable cost, if the shafts of the 0 two drive motors are rigidly connected together by means of flange connections. In this arrangement, it is expedient for the two rotors of the drive motors to be jointly supported in two bearings arranged at both ends of the rotors. - Further cost advantages can be 1999 P 04206 WO - 5 achieved if a water cooling system is provided for the lower power drive motor only, whereas an air cooling system is associated with the higher power drive motor. Similar advantages arise if each of the two drive 5 motors has its own power electronics unit associated with it. Two exemplary embodiments of the new propulsion device are represented diagrammatically in figures 1 and 2. In 10 the drawing: fig. 1 shows a propulsion device, in which the rotor of the lower power drive motor is coupled in an overhung manner to the rotor shaft of the 15 higher power drive motor, and fig. 2 shows a propulsion device, in which the rotors of the two drive motors are jointly supported between two bearings. 20 Fig. 1 shows a propulsion device in which a first, higher power electrical drive motor 10 and a second, lower power electrical drive motor 20 are arranged immediately adjacent to one another. For this purpose, the two stator casings 11 and 21 of the drive motors 5 are connected together. In addition, the shaft 23 of the drive motor 20, on which the rotor 22 is seated, is flanged by means of coupling flanges 11 and 21 to the shaft 13 of the drive motor 10, on which the rotor 12 is seated. A casing 1, which is arranged concentrically 0 relative to the motor and which forms an annular space 2, is associated with the lower power drive motor 20. The power electronics, together with cooling pumps and further units necessary for operating the drive motor 20, can be arranged in this annular space.

1999 P 04206 WO -6 Both the drive motor 10 and the drive motor 20 are configured as multiphase alternating current motors with static converter supply, the lower power drive motor 20 being a synchronous motor with permanently 5 excited rotor whereas the larger drive motor 10 is configured as an asynchronous motor. The drive motor 10 can, for example, have a rated power of 4 MW in a rotational speed range from approximately 45 to 150 rpm. On the other hand, the drive motor 20 has, for 10 example, a rated power of approximately 150 kW in a rotational speed range from 0 to 46 rpm. The power electronics for the drive motor 10, which takes up substantially more space than the power 15 electronics for the drive motor 20, is expediently installed in a separate switch-gear installation, which can be erected next to the motor 10. In principle, the propulsion device according to fig. 2 20 is similarly constructed to the propulsion device according to fig. 1. An essential difference consists in the arrangement of the two bearings 16 and 26. As a departure from the exemplary embodiment according to fig. 1, in which an overhung support of the rotor 22 of 25 the drive motor 20 is provided by means of the coupling flanges 14 and 24, the shafts 17 and 27 of the rotors of the two drive motors are, in this case, matched to one another in such a way that they form a joint piece of shafting, which is jointly supported in the two 30 bearings 16 and 26 at both ends of the two rotors. In the exemplary embodiment according to fig. 2, the power electronics, together with the cooling pumps and electronic units, such as rotational speed and 1999 P 04206 WO - 7 monitoring computer, are accommodated in a casing 28 placed on the drive motor, whereas the cooling device 18 is placed on the higher power drive motor, the cooling device 18 consisting essentially of a fan and 5 an air/water recooling unit. A water cooling system is provided for cooling the stator of the lower power drive motor, the corresponding cooling connections 29 being indicated 10 diagrammatically. The rotor of the lower power drive motor is additionally provided with fan vanes 30, which support the cooling of the winding heads of the stator.

Claims

1. A propulsion device for a ship which has, essentially, two operating ranges for a propeller, 5 which has direct electric motor drive via a drive shaft, namely a first operating range for propeller rotational speeds up to approximately 30% of the rated rotational speed and a second operating range for the propeller rotational speeds extending beyond this speed 10 up to the rated rotational speed, in which a multiphase alternating current motor with static converter supply is provided as drive motor (10), characterized in that a second electric motor (20), which is likewise configured as a multiphase alternating current motor 15 with static converter supply, is arranged on the drive shaft (13, 23) and in that the two electric motors (10, 20) differ in their rated power in such a way that the power ratio is greater than/equal to 20:1. 20

2. The propulsion device as claimed in claim 1, characterized in that the smaller power drive motor (20) is configured as a salient pole machine excited by direct current. 25

3. The propulsion device as claimed in claim 1, characterized in that the smaller power drive motor (20) has a rotor with permanent magnet excitation.

4. The propulsion device as claimed in one of 30 claims 1 to 3, characterized in that the higher power drive motor (10) is configured as an asynchronous motor. 1999 P 04206 WO - 9

5. The propulsion device as claimed in one of claims 1 to 3, characterized in that the higher power drive motor (10) is configured as a synchronous motor with permanently excited rotor. 5

6. The propulsion device as claimed in one of claims 1 to 3, characterized in that the higher power drive motor (10) is configured as a synchronous motor with non-salient pole rotor or salient pole rotor 10 excited by direct current.

7. The propulsion device as claimed in one of claims 1 to 6, characterized in that the power ratio between the two drive motors is greater than 50:1. L5

8. The propulsion device as claimed in one of claims 1 to 7, characterized in that the shafts (13, 23) of the two drive motors (10, 20) are rigidly connected together by means of a flange connection (14, ?0 24).

9. The propulsion device as claimed in one of claims 1 to 8, characterized in that the two rotors (12, 22) of the drive motors are jointly supported in !5 two bearings (16, 26) arranged at both ends of the rotors.

10. The propulsion device as claimed in one of claims 1 to 9, characterized in that the lower power 0 drive motor (20) includes a water cooling system (29), which is supplied from the fresh-water cooling circuit of the ship, and in that an air cooling system (18) is associated with the higher power drive motor (10). 1999 P 04206 WO - 10

11. The propulsion device as claimed in one of claims 1 to 10, characterized in that each of the two drive motors (10, 20) has its own power electronics unit associated with it. 5

12. The propulsion device as claimed in claim 11, characterized in that the power electronics unit of the lower power drive motor (20) is accommodated in the casing (1, 28) of this drive motor.