AU2011231682B2

AU2011231682B2 - Method for operating a ship drive motor fed by at least one pulse width modulated inverter, and ship drive system

Info

Publication number: AU2011231682B2
Application number: AU2011231682A
Authority: AU
Inventors: Jurgen Eckert; Dieter Scholz
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2010-03-25
Filing date: 2011-03-23
Publication date: 2013-11-14
Anticipated expiration: 2031-03-23
Also published as: EP2550196B1; KR20120128697A; BR112012024313A2; BR112012024313B1; RU2514383C1; KR101485647B1; ES2473568T3; AU2011231682A1; RU2012145350A; WO2011117278A1; EP2550196A1

Abstract

The invention relates to a method for operating a ship drive motor (2) fed by at least one pulse width modulated inverter (3), wherein circuit elements (5) of the pulse inverter (3) are switched at a changeable switching frequency, wherein according to the invention the switching frequency is controlled manually by the operating personnel of the ship independently of the operating state of the ship drive motor (2) and the pulse inverter (3), in order to change an acoustic noise spectrum of the ship. The operating personnel of the ship can thereby selectively set a noise spectrum of the ship adapted to the requirements and conditions present at a particular time for operating the ship.

Description

PCT/EP2011/054412 / 201OP03561WO 1 Description METHOD FOR OPERATING A SHIP DRIVE MOTOR FED BY AT LEAST ONE PULSE WIDTH MODULATED INVERTER, AND SHIP DRIVE SYSTEM The invention relates to a method for operating a ship drive motor fed by at least one pulse width modulated inverter in accordance with the preamble of claim 1 and to a ship drive system with such a ship drive motor in accordance with the preamble of claim 6. During operation of a ship drive motor fed by a pulse inverter it is known that the switching elements of the pulse inverter (frequently also referred to as "valves") are switched with a switching frequency which either does not change or only changes as a function of changes of the operating state of the ship drive motor and/or of the pulse inverter. In such cases, particularly in stationary operation, this can result in perceivable harmonics in the noise spectrum of the machine and thus also of the ship. In the acoustic noise spectrum of the ship, frequently also referred to as the "acoustic signature" of the ship, there are then one or more spectral lines with a markedly increased peak value, while other areas of the spectrum are only characterized by very low values. When the ship is used as a research vessel the noises generated by this can disturb measurements in the water. Furthermore these noises can disturb marine life, which exhibit a particular sensibility particularly in the areas of the spectral lines with the peak values. This can mean for conservation reasons for example, that radius of movement of cruise ships or ferries is restricted. In the case of submarines the noises can lead to an increase in the detectability of the submarine.

2 A method for operating a machine fed by a pulse inverter is known from DE 39 12 706 Al, in which the switching frequency of the switching elements of the pulse inverter is constantly automatically changed independently of the operating state of the ship drive motor and of the pulse inverter. The switching frequencies and the times at which they are changed are predetermined in this method by a random generator for example. Then, instead of a single or a few high spectral lines, a more or less continuous spectrum with a far lower peak value occurs in the noise spectrum of the motor. Changing the switching frequency of the switching elements of the pulse inverter for noise reduction depending on a defined function is known from EP 0 685 923 BI whereby, through explicit setting of parameters in the function, an even distribution of harmonics across the frequency spectrum is achieved and thus the noses are reduced. US 2003/0052642 Al discloses a drive system in which a desired required switching frequency can be selected manually by a user. However this required switching frequency is partly changed again by an inverter control as a function of a required value for the frequency of the output voltage of the inverter in order to avoid distortions of the inverter output voltage as a result of parasitic effects. WO 02/957133 A2 discloses a method for operating a ship drive motor fed by at least one inverter unit, in which the current inverter control of the inverter unit is able to be freely configured such that the acoustic signature is controlled by the operating personnel of the ship, in order to change an acoustic noise spectrum of the ship. Although these solutions allow the overall nose level to be lowered noises are still generated in inherently undesired frequency ranges. The background discussion (including any potential prior art) is not to be taken as an admission of the common general knowledge in the art in any country. Any references discussed state the assertions of the author of those references and not the assertions of the applicant of this application. As such, the applicant reserves the right to challenge the accuracy and relevance of the references discussed. It is acknowledged that the terms "comprise", "comprises" and "comprising" may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, these terms are 3 intended to have an inclusive meaning - i.e. they will be taken to mean an inclusion of the listed components that the use directly references, but optionally also the inclusion of other non-specified components or elements. It will be understood that this intended meaning also similarly applies to the terms mentioned when used to define steps in a method or process. Thus, a need exists for, to avoid such problems, a method for operating a ship drive motor fed by at least one pulse inverter in accordance with the preamble of claim 1 and for a ship drive system in accordance with the preamble of claim 6 or to at least provide the public with a useful choice. The object directed to the method is successfully achieved by a method according to claim 1. Advantageous embodiments are the subject matter of claims 2 to 5. The object directed to the ship drive system is successfully achieved by ship drive system according to claim 6. Advantageous embodiments are the subject matter of claims 7 to 10. A ship with such a ship drive system is the subject matter of claim 11. A method for operating such ship is the subject matter of claim 12. In the inventive method the switching frequency is controlled manually by operating personnel independently of the operating state of the ship drive motor and of the pulse inverter, i.e. for example independently of the output voltage of the pulse inverter or of the input voltage of the ship drive motor and/or of the speed of the ship drive motor. Thus the switching frequency and the time as from which the pulse inverter is operated with the switching frequency determined by the operating personnel is not determined automatically but manually by the operating personnel. It is thus possible for the operating personnel of the ship to change the noise spectrum (i.e. the acoustic signature) of the ship and thus to explicitly set a specific desired nose spectrum of the ship. The noise spectrum can then be adjusted explicitly in accordance with the requirements and general conditions for operation obtaining at a specific time. For example with a research ship it can be set so that it does not disturb underwater measurements. With a cruise ship or ferry it can be adjusted so that it does not disturb certain marine life. In the case of the submarine it can be adjusted for example so that it makes the vessel more difficult to detect. The operating 4 personnel can be located on board the ship or outside the ship in such cases for determining the switching frequency, wherein in the latter case they control the switching frequency by remote control. The switching frequency can be controlled by the crew here directly by specifying the switching frequency or also indirectly by specifying a parameter assigned to the switching frequency. In this case the ship's motor is fed by a number of pulse inverters, wherein the switching elements of all pulse inverters are operated with the same switching frequency in each case, so that cumulatively they also generate a desired noise spectrum. To increase the user-friendliness the crew can be provided with a selection of a restricted number of possible switching frequencies and the crew can control the switching frequency by choosing one of these switching frequencies. In a particularly user-friendly embodiment of the method for the crew the switching frequencies are each assigned a signature type. The crew can then be offered a choice of the signature types and the crew controls the switching frequency by selecting one of the signature types. The signature types can represent defined different noise spectrums or reflect usage conditions of the ship. The crew can thus, in an especially simple manner and without precise knowledge of the exact switching frequencies, control the switching frequency solely on the basis of the signature type. Ultimately however a signature type represents a defined acoustic noise spectrum of the ship (i.e. the "acoustic signature" of the ship), which for its part is characterized by one or more spectral lines 4a with a greatly increased peak value compared to other areas of the spectrum with comparatively far lower values. In accordance with an especially advantageous embodiment the control pulses for the switching elements of the pulse inverter are generated by modulation of a required value with a modulation frequency and for control of the switching 5 frequency the switching elements are controlled with the modulation frequency independent of the required value. If the ship drive motor is supplied by a number of pulse inverters, the switching elements of all pulse inverters are preferably operated with the same switching frequency in each case, so that cumulatively they also generate a desired noise spectrum. With the inventive ship drive system the device for generating the switching pulses for a manual control of the switching frequency by operating personnel of the ship is coupled to an input device. The stated advantages relating to the inventive method apply correspondingly to the inventive ship drive system. The input device can for example be disposed for easy access for the crew on the bridge of the ship, while the ship drive motor, the pulse inverter and the device for generating the switching pulses are located in the machine room of the ship. In this case the ship drive system has a number of pulse inverters for supplying the ship drive motor and in each case has a separate device for generating switching pulses of variable switching frequency for each of the pulse inverters, wherein all devices for generating switching pulses are coupled to the input device. This enables it to be ensured that all pulse inverters are operated with the same switching frequency and also cumulatively generate a desired noise spectrum. To make it more user-friendly, the input device can in this case be embodied such that it provides the operating personnel 5a with a restricted number of possible switching frequencies and that one of the switching frequencies is able to be selected by the operating personnel for controlling the switching frequency. In an especially user-friendly embodiment for the crew the switching frequencies are assigned a signature type in each case and the input device is embodied so as to offer the operating personnel a selection of the signature types assigned to the switching frequencies and that one-of the signature types is able to be selected by the operating 6 personnel for controlling the switching frequency. Preferably the device for generating the switching pulses is embodied such that it generates the switching pulses for the switching elements of the pulse inverter by modulating a required value with a modulation frequency and that the switching frequency of the switching elements is controlled by controlling the modulation frequency independently of the required value. The invention and also further advantageous embodiments of the invention in accordance with features of the subclaims are explained in greater detail below, with reference to the exemplary embodiments in the figures, in which: FIG. 1 shows a first exemplary embodiment for an inventive ship drive system, FIG. 2 shows a method used advantageously for generating switching pulses and FIG. 3 shows a second exemplary embodiment for an inventive ship drive system. FIG. 1 shows a ship drive system 1 with an electrical ship drive motor 2, which is connected to a three-phase pulse PCT/EP2011/054412 / 201OP03561WO 7 inverter 3 and is supplied by said inverter with electrical energy. The pulse inverter 3 here has three half bridges 4 each with two switching elements 5 (e.g. semiconductor switches) and is fed on the input side by a predetermined DC voltage U, e.g. a battery voltage or an impressed DC link circuit voltage of a DC link circuit inverter. The ship drive motor 2 is embodied as an alternating current machine with a three-phase winding system 11 and is coupled to a ship's propeller in a way not shown in any greater detail in the diagrams. For the feed voltage of the motor 2 a required value a and a desired frequency fa are prespecified to a device 6 for generating switching pulses for the switching elements 5 of the pulse inverter 4 by a drive control 9. The required values determine the curve of the required value for the feed voltage of the motor 2 shown in FIG. 2 by R, which is compared in a pulse width modulator 8 with a sawtooth-shaped modulation voltage D. Their intersection points define a pulse width modulated control voltage S, from the flanks of which the control pulses for the switching elements 5 of the pulse inverter 3 are derived. This pulse width modulator 8, operating in accordance with the known "pulse width modulation method", is fed by a control signal fT which specifies the frequency of the sawtooth-shaped modulation voltage. The control signal fT for the modulation frequency can be formed in the prior art as a function of the required values a and fa in the modulator 8 of the device 6 itself, so that a separate control input is not present. In particular a microprocessor can be used as the pulse width modulator 8 which, without forming the sawtooth voltage directly, computes the control flanks of the control signal S. The modulation PCT/EP2011/054412 / 201OP03561WO 8 frequency then does not change in the prior art or only changes as a function of the operating state of the motor 2 or of the pulse inverter 3. In the stationary operating state the modulation frequency fT is constant. In accordance with another solution known from the prior art the control signal can be delivered for the modulation frequency fT by a noise generator, which generates the modulation frequency fT in accordance with a statistical calculation, for which an average value and a bandwidth is prespecified. This enables a Gaussian distribution of the modulation frequency fT to be obtained for example. In a further solution known from the prior art the desired modulation frequency fT, although it can be predetermined manually by a user, is partly changed again by an inverter control as a function of a required value for the frequency of the output voltage of the pulse inverter or the feed voltage of the motor 2. By contrast, in FIG. 1 the pulse width modulator 8 is controlled by a control signal fT for the modulation frequency, which is generated by an input/output unit 10 as a function of a manual input of the crew and is passed on independently of the required values a and fa (i.e. for example independently of the frequency and level of the output voltage of the pulse inverter 4 of the input voltage of the motor 2 and thus of the speed of the motor 2) via the drive regulator 9 to the device 6 for generating the control pulses. The device 6 for generating the switching pulses is thus coupled for manual control of the switching frequency by operating personnel of the ship via the drive regulator 9 to the input/output unit 10. As an alternative the device 6 for generating the PCT/EP2011/054412 / 2010P03561WO 9 switching pulses can also be coupled directly to the input/output unit 10 or indirectly via other components of the ship drive system 1 to the input/output unit 10. To this end the input/output unit 10 is located on the bridge of the ship, while the pulse inverter 3 and the drive motor 2 are located in the machine room of the ship. By means of the input/output unit 10 the crew is able to control the switching frequency manually from the bridge independently of the operating state of the ship drive motor 2 and the pulse inverter 3. Thus the switching frequency, the time from which the pulse inverter 3 is operated with this switching frequency and the duration of operation at this switching frequency can be determined manually by the crew. One or more spectral lines with a markedly higher peak value then occur explicitly as a function of the switching frequency in the frequency spectrum of the output voltage of the pulse inverter 3. Accordingly the noise spectrum of the motor 2 also changes and thereby the signature of the ship. The switching frequency is perceivable therein as a single distinctive peak or a number of distinctive individual peaks in the spectrum, while other areas of the spectrum are characterized by very small values. This makes it possible for the crew of the ship to change the noise spectrum (i.e. the acoustic signature) of the ship and thus to explicitly set a specific desired noise spectrum of the ship. The crew and the input/output unit can also be located outside the ship for controlling the switching frequency and can control the switching frequency by remote control.

PCT/EP2011/054412 / 2010203561WO 10 The input/output unit 10 can be embodied in such cases so that it outputs a restricted number of possible switching frequencies provided to the crew for their selection. The crew can then select one of these switching frequencies to determine the switching frequency. In an especially user-friendly embodiment for the crew the switching frequencies are each assigned a signature type and the input/output unit 10 is embodied such that it outputs to the crew the signature types assigned to the switching frequencies and provides them for their selection. For the crew one of the signature types is then able to be selected for controlling the switching frequency. The signature types can be distinguished for example by the arrangement of the spectral lines with markedly increased peak values in the spectrum. The input/output unit 10 then converts the desired signature type into an assigned modulation frequency fT. As an alternative this conversion can naturally also take place in the drive regulator 9 or in the devices 6. The input/output unit 10 can for example involve a touchscreen. The crew can for example select a desired signature type, i.e. a desired arrangement of the spectral lines with markedly increased peak values in the spectrum at the start of the voyage and thus set the assigned switching frequency. The crew can then also explicitly switch during the voyage between different signature types or switching frequencies. Instead of only a single three-phase winding system 11, the motor 2 can naturally also have a number of winding systems each of which is fed by its own pulse inverter, wherein all PCT/EP2011/054412 / 2010P03561WO 11 pulse inverters are operated with the same switching frequency. An inventive ship drive system 20 shown in FIG. 3 differs from the ship drive system 1 shown in FIG. 1 in that the electrical ship drive motor 2 has a number (for example 12) of winding lines 12 each fed by a single-phase pulse inverter 3 of which only three are shown in order to simplify the diagram. Each of the pulse inverters 3 in this case has two half bridges 4 each with two switching elements 5 (e.g. IGBT semiconductor switches). The ship drive system 20 for example involves a ship drive system for a submarine in which, for noise reduction and for reasons of redundancy, this type of single strand feed is advantageous. The ship drive system 20 has a separate device 6 in each case for generating switching pulses of variable switching frequency for each of the pulse inverters 3. In this case all devices 6 for generating switching pulses are connected to a common drive regulator 9 which prespecifies to the devices 6 for generating the switching pulses - as explained in connection with FIG. 1 - a required value a, a required frequency fa and a modulation frequency fT. The modulation frequency fT is received by the drive regulator 9 for its part from the input/output unit 10, by which the crew controls the switching frequency of the switching elements 5 of the pulse inverter 3 and thus the noise spectrum of the ship independently of the required frequency fa. Since all devices 6 for generating switching pulses are coupled via the drive regulator 9 to the same input/output unit 10 it is ensured that they will also be operated with the same switching frequency.

Claims

1. A method for operating a ship drive motor fed by at least one pulse inverter, in which switching elements of the 5 pulse inverter are switched with a variable switching frequency, wherein the switching frequency is controlled manually independently of the operating state of the ship drive motor and of the pulse inverter by crew of the ship in order to change an acoustic noise spectrum of the ship, 10 wherein the ship drive motor is fed by a number of pulse inverters, wherein the switching elements of all pulse inverters are operated with the same switching frequency in each case. is

2. The method as claimed in claim 1, wherein the crew is provided with a choice of a restricted number of possible switching frequencies and that the crew controls the switching frequency by selecting one of these frequencies. 20

3. The method as claimed in claim 2, wherein the switching frequencies are each assigned a signature type and the crew is provided with a choice of the signature types, wherein the crew controls the switching frequency by selecting one of the signature types. 25

4. The method as claimed in any one of the preceding claims, wherein the control pulses for the switching elements of the pulse inverter are generated by modulation of a required value with a modulation frequency, for control 30 of the switching frequency of the switching elements the modulation frequency is controlled independently of the required value. 6683283_I:wxb 13

5. A ship drive system with a ship drive motor, at least one pulse inverter with switching elements for feeding the ship drive motor and with a device for generating switching pulses of variable switching frequency for the switching 5 elements of the pulse inverter, wherein the device for generating the switching pulses is embodied such that the switching frequency is able to be controlled independently of the operating state of the ship drive motor and of the pulse inverter, wherein the device for generating the to switching pulses is coupled to an input device for manual control of the switching frequency by crew of the ship, in order to change an acoustic noise spectrum of the ship, wherein a number of pulse inverters for feeding the ship drive motor and respectively a separate device for is generating switching pulses of variable switching frequency for each of the pulse inverters, with all devices for generation of switching pulses being coupled to the input device. 20

6. The ship drive system as claimed in claim 5, wherein the input device is embodied such that the input device provides the crew with a selection of a restricted number of possible switching frequencies and that one of these frequencies is able to be selected by the crew for control 25 of the switching frequency.

7. The ship drive system as claimed in claim 6, wherein the switching frequencies are each assigned a signature type and that the input device is embodied such that the input 30 device provides the crew with a selection of the signature types and that one these signature types is able to be selected by the crew for control of the switching frequency. 6683283_l:wxb 14

8. The ship drive system as claimed in any one of claims 5 to 7, wherein the device for generating the switching pulses is embodied such that the generating device generates the switching pulses for the switching elements of 5 the pulse inverter by modulation of a required value with a modulation frequency and the switching frequency of the switching elements is controlled by controlling the modulation frequency independently of the required value. 10

9. A ship with a ship drive system as claimed in any one of claims 5 to 8.

10. A ship as claimed in claim 9, wherein the ship is a submarine. 15

11. A method for operating a ship as claimed in claim 9 or 10, in which the switching frequency is changed by the crew of the ship manually while the ship is at sea. 20 DATED this Seventh Day of September, 2012 Siemens Aktiengesellschaft Patent Attorneys for the Applicant SPRUSON & FERGUSON 25 6683283 1:wxb