DC propulsion ship generator and control method thereof

Abstract

The present invention provides a generator for a DC propulsion marine vessel based on DC power and a control method thereof. The generator for a DC propulsion marine vessel according to one embodiment of the present invention includes a synchronous generator that generates an AC voltage, an active front end (AFE) converter connected to an output terminal of the synchronous generator and converting the AC voltage into a DC voltage, and an automatic voltage regulator (AVR) that controls a field current so that a magnetic flux of a stator of the synchronous generator is maintained at a constant magnetic flux, and a sensor for measuring a rotational speed of the synchronous generator may be omitted.

Description

[Technical Field]

[0001] The present invention relates to a power generating device for a DC propulsion ship and a control method thereof. [Background technology]

[0002] Electric propulsion systems, including generators, are commonly used to produce electrical energy for consumption by various electrical devices, such as on ships.

[0003] The electrical energy generated is used to power the equipment necessary to propel the ship and power the various components and systems involved in the operation of the ship. Passengers on passenger ships also consume significant amounts of electrical energy through their direct or indirect use of the electrical amenities on board.

[0004] It is known to provide electrical energy to a vessel by generating AC power using a generator coupled to a prime mover, which uses various energy sources, such as diesel fuel and fuel oil, to generate rotational motion for the generator, and the AC power is converted to a suitable voltage level for different purposes.

[0005] Recently, due to environmental concerns and increased fuel efficiency, electric propulsion systems based on direct current, which allow variable speed operation of the generator engine, have been applied. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Korean Patent No. 10-194895 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a power generating device for a DC propulsion ship that utilizes an AFE converter and a control method thereof.

[0008] An object of the present invention is to provide an apparatus and a control method for fixing the magnetic flux of a synchronous generator by controlling the field current without a filter or a magnetic flux estimation sensor using an AFE converter and an AVR in FCR mode.

[0009] The object of the present invention is not limited to the above-mentioned objects, and further objects not mentioned here will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides the following DC propulsion marine power generating apparatus.

[0011] A generator for a DC propulsion marine vessel according to an embodiment of the present invention includes a synchronous generator that generates an AC voltage, and an active front end (AFE) converter connected to an output terminal of the synchronous generator and converting the AC voltage into a DC voltage.

[0012] A method for controlling a power generating system for a DC propulsion marine vessel according to an embodiment of the present invention includes the steps of: generating an AC voltage using a synchronous generator; and converting the AC voltage into a DC voltage using an active front end (AFE) converter. [Effects of the Invention]

[0013] According to an embodiment of the present invention, the field current can be controlled using an AFE converter and an AVR in FCR mode to fix the magnetic flux of a synchronous generator without using a filter and an encoder. [Brief explanation of the drawings]

[0014] [Figure 1a] 1 shows an example of a conventional AC propulsion ship. [Figure 1b] 1 shows an example of a conventional DC propulsion vessel. [Figure 2]1 shows an example of a direct current propulsion vessel according to an embodiment of the present invention. [Figure 3] 1 shows an example of a direct current propulsion vessel according to an embodiment of the present invention. [Figure 4] 1 is a configuration diagram of a direct current propulsion marine vessel system according to an embodiment of the present invention. [Figure 5] 1 is a schematic configuration diagram of a DC propulsion marine power generating device according to an embodiment of the present invention; [Figure 6] 1 is a schematic configuration diagram of a DC propulsion marine power generating device according to an embodiment of the present invention; [Figure 7] 1 is a schematic configuration diagram of a DC propulsion marine power generating device according to an embodiment of the present invention; [Figure 8] 1 is a schematic configuration diagram of a DC propulsion marine power generating device according to an embodiment of the present invention; [Figure 9] 4 is a graph showing electrical characteristics of a marine propulsion power generating device according to an embodiment of the present invention. [Figure 10] FIG. 4 is a diagram showing a field current of the marine propulsion generator according to one embodiment of the present invention. [Figure 11] FIG. 1 illustrates an exemplary computing environment in which a converter for a marine propulsion power plant according to an embodiment of the present invention may be implemented. [Figure 12] 3 is a flowchart showing a method for controlling a DC propulsion marine power generating apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, in describing the preferred embodiments of the present invention in detail, if it is determined that a detailed description of related known functions or configurations may obscure the gist of the present invention, such detailed description will be omitted. Furthermore, the same reference numerals will be used throughout the drawings to refer to parts having similar functions and functions.

[0016] Throughout this specification, when a part is referred to as being "connected" to another part, this includes not only "directly connected" but also "indirectly connected" via another element therebetween. Furthermore, unless otherwise specified, "comprising" a certain component does not mean excluding other components, but means that other components can be further included.

[0017] As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

[0018] FIG. 1 shows an example of a generator end of a conventional DC propulsion ship.

[0019] FIG. 1a shows an example of a conventional AC propulsion ship.

[0020] Referring to FIG. 1a, a conventional AC propulsion vessel 1 may include an engine 14, a governor (GVR) 15, a generator 11, an automatic voltage regulator (AVR) 13, a power and energy management system (PEMS) 16, a converter 17, an inverter 18, and a motor 19.

[0021] Generally, conventional ships use AC voltage for main power distribution, so there is no need to use a separate converter to transmit the AC voltage output from the generator 11 to the switchboard. Therefore, the AC voltage generated by the generator 11 is directly connected to the AC switchboard and supplied to the load end or the propulsion motor end. In this case, to improve energy efficiency, a converter 17 (AFE or DFE) that converts AC voltage to DC voltage and an inverter 18 that converts DC voltage to AC voltage can be used at the propulsion motor end. In addition, the AVR 13 can function to stabilize the voltage of the AC power generated by the generator 11.

[0022] FIG. 1b shows an example of a conventional DC propulsion vessel.

[0023] Referring to FIG. 1b, a conventional DC propulsion vessel 2 may include a generator 11, a diode front end (DFE) converter 12, an automatic voltage regulator (AVR) 13, an engine 14, a governor (GVR) 15, an inverter 18, and a power and energy management system (PEMS) 16.

[0024] The generator 11 can generate AC voltage, and the DFE converter 12 can convert the AC voltage generated by the generator 11 into DC voltage. The automatic voltage regulator 13 can automatically control unstable voltage fluctuations to a constant level and provide a uniform output voltage, and can generally be used for AC voltage. The governor 15 can control the engine rotation speed, and the PEMS 16 can control the overall power system of the ship.

[0025] The PEMS 16 is connected to a DC switchboard of the DC propulsion vessel 2 and can control the engine 14 by transmitting instructions to a governor 15 that controls the engine 14.

[0026] A converter that converts AC electricity generated by a generator 11 into DC electricity is essential at the generating end 1 of a DC propulsion ship, and a DFE converter 12 has generally been used at the generating end 1 of conventional DC propulsion ships.

[0027] However, although the DFE converter 12 has the advantages of a simple circuit configuration and low cost, it has the problems of being unable to achieve high-precision control because the PEMS 16 cannot control the DFE converter 12 independently, and the control method is complicated because the engine variable speed control and the generator voltage control are coupled, and there are limitations to DC voltage control, resulting in poor system stability.

[0028] FIG. 2 shows an example of a power generating end of a DC propulsion vessel according to an embodiment of the present invention.

[0029] 2, an active front end (AFE) converter 23 can be used instead of a DFE converter in the DC propulsion vessel 3. As a result, the DC propulsion vessel 3 can include a generator 21, an LCL filter 22b, the active front end (AFE) converter 23, an AVR 24, and a magnetic flux estimation sensor 22a. The DC propulsion vessel 3 can further include an engine 25, a GVR 26, and a PEMS 27.

[0030] The AFE converter 23 has the advantage of being able to control the power factor at the generating end to 1, convert AC power to DC power, and independently control the magnetic flux and DC voltage of the generator 21. As a result, unlike the DFE converter 12, the variable speed control of the engine and the voltage control of the generator are decoupled, simplifying the control method and facilitating DC voltage control, thereby improving system stability. In addition, the operating range of the engine is increased compared to the DFE converter 12, improving fuel efficiency through variable speed.

[0031] The AFE converter 23 generates a pulse wave through PMW switching operation, but the control method applied to conventional AVRs is AVR mode (Automatic Voltage Regulator Mode), which is applicable when the output voltage at the generating end is a sine wave, so an LCL filter 22b is required to convert the pulse wave into a sine wave.

[0032] However, using the LCL filter 22b not only increases the volume of the system, but also can cause power loss and cooling loss. In particular, in a DC propulsion system that is expected to improve efficiency by variable speed of the generator engine, optimal filter design and control are impossible because the frequency and voltage change depending on the engine speed. Therefore, it is desirable to omit the LCL filter 22b.

[0033] Meanwhile, the AFE converter 23 requires information on the rotational position and rotational speed (RPM) of the generator (rotating machine) to estimate the magnetic flux of the stator of the generator 21, and for this purpose, a sensor such as an encoder is typically used. The information on the rotational position and speed of the generator obtained using the sensor is input to the AFE converter 23, but converters that switch in the high frequency range have the disadvantage of being susceptible to noise. Furthermore, the system cannot operate if the corresponding cable is lost. Therefore, it is desirable to omit the magnetic flux estimation sensor such as an encoder.

[0034] In addition, since small and medium-sized vessels have limited space, it is necessary to remove the encoder and filter to reduce the volume of the generating end.

[0035] FIG. 3 shows an example of a direct current propulsion vessel according to an embodiment of the present invention.

[0036] In one embodiment of the present invention, an AFE converter is used in place of a DFE converter, which has a complex control method because the engine variable speed control and the generator voltage control are coupled, has limitations in DC voltage control, and is inferior in system stability.In this embodiment, an AFE converter is used in place of a DFE converter, which has a simple control method because the engine variable speed control and the generator voltage control are decoupled, and is easy to control DC voltage.

[0037] Referring to FIG. 3, in a DC propulsion vessel 4 according to an embodiment of the present invention, the AVR operates in a Field Current Regulator Mode (FCR mode) instead of an AVR mode, so that the magnetic flux estimation sensor 22a and the LCL filter 22b of FIG. 2 can be omitted.

[0038] As explained with reference to Figure 2, when the AVR operates in AVR mode, the AVR generates a command voltage by PWM (pulse width modulation) switching of active elements, which generates harmonic components due to switching. Therefore, an LCL filter 22b is required to remove noise and convert it to a sine wave.

[0039] Meanwhile, when the AVR 24 operates in FCR mode (Field Current Regulator Mode), the LCL filter 22b can be omitted because the command is calculated using the field current and transmitted to the AVR. This improves the operating efficiency of the generator terminal 2 of the DC propulsion ship and reduces the volume of the generator terminal. In addition, the AFE converter 23 estimates the rotor angle and stator magnetic flux of the generator 21 to generate a magnetic flux control signal, allowing for the application of a sensorless system that does not use an encoder. This provides a generator and control method for a DC propulsion ship that is less susceptible to noise, eliminates the risk of cable loss, and can fix the generator's magnetic flux.

[0040] FIG. 4 is a configuration diagram of a direct current propulsion marine vessel system according to one embodiment of the present invention.

[0041] Referring to FIG. 4, a DC propulsion marine system 100 according to one embodiment of the present invention may include a DC propulsion marine power generation device 110, a load end 120, a battery system 130, a motor load end 140, a bus tie 150, and a DC switchboard 160.

[0042] The DC propulsion marine power plant 110 generates AC power and converts it to DC power, which can be supplied to the necessary components by a DC switchboard 160 .

[0043] The load terminal 120 receives DC power from the DC switch board 160 and can perform a preset operation.

[0044] The battery system 130 receives or provides DC power from a DC switchboard 160, and can charge and discharge power.

[0045] The motor load terminal 140 receives DC power from the DC switch board 160 and converts it into AC power, thereby driving a motor used for propelling a ship or the like.

[0046] The DC propulsion marine power generating apparatus 110, the load end 120, the battery system 130, and the motor load end 140 may be provided in plural numbers, and the DC switchboard 160 can supply DC power from the DC propulsion marine power generating apparatus 110 to the load end 120, the battery system 130, and the motor load end 140, respectively. In addition, a bus tie 150 is disposed between the DC switchboards 160, and can cut off the transmission of power when an abnormal state such as a fault occurs.

[0047] The present invention described below relates to a DC propulsion marine power generating system 110 and its control method, and provides a structure and control method for efficiently operating the engine at variable speeds while taking advantage of the advantages of DC propulsion.

[0048] 5 to 8 are schematic diagrams of a DC propulsion marine power generating system according to one embodiment of the present invention.

[0049] 5, the generator 110 for a DC propulsion marine vessel according to an embodiment of the present invention may include an AFE converter 111, a synchronous generator 112, and an automatic voltage regulator (AVR) 113. The generator 110 for a DC propulsion marine vessel according to an embodiment of the present invention may perform feedback control to maintain the voltage of the DC switchboard 160 or the output DC voltage of the AFE converter 111 constant. The AFE converter 111 may convert the AC voltage of the synchronous generator 112 into a DC voltage and supply it to the DC switchboard 160, and the output DC voltage of the AFE converter 111 may be the same as the supply voltage of the DC switchboard 160. In addition, the generator 110 for a DC propulsion marine vessel according to an embodiment of the present invention may perform feedback control to maintain the magnetic flux of the synchronous generator 112 constant.

[0050] The AFE converter 111 is connected to the output end of the synchronous generator 112 and controls the power factor to "1" to convert AC power output from the synchronous generator 112 into DC power. Unlike a general Diode Front End (DFE) type rectifier, the AFE converter 111 can independently control the magnetic flux and DC power of the generator.

[0051] The AFE converter 111 of the present invention can estimate the magnetic flux of a stator of the synchronous generator 112, generate a magnetic flux control signal for fixing and controlling the magnetic flux of the stator, and transmit the generated magnetic flux control signal to the AVR 113. The AVR 113 can control the field current of the synchronous generator 112 in response to the magnetic flux control signal. The magnetic flux control signal can include a field current reference value.

[0052] According to an embodiment of the present invention, a sensor for estimating the rotation speed (rpm) of the synchronous generator can be omitted because the AFE converter 111 can estimate the magnetic flux and output the magnetic flux control signal. The magnetic flux estimation sensor can include an encoder for measuring the rotation speed of the rotor of the synchronous generator.

[0053] The synchronous generator 112 is a synchronous AC generator that converts mechanical power into electrical output and may include a stator and a rotor. The stator may be made up of an armature winding and may be a part that generates induced electromotive force. The rotor may be made up of a field winding and may be capable of generating a magnetic field. In the synchronous generator 112, the mechanical rotation of the rotor and the rotating magnetic field of the stator have the same rotation speed, and the rotation speed may be proportional to the frequency of the current induced in the armature.

[0054] In one embodiment, the synchronous generator 112 may be a wound rotor synchronous generator (WRSG), which may have a configuration in which both the rotor and the stator are configured with three-phase windings.

[0055] The automatic voltage regulator (AVR) 113 can control the field current to control the magnetic flux of the synchronous generator 112. The AVR 113 can generate a field current control signal for controlling the field current based on a magnetic flux control signal including a field current reference value. The AVR 113 can generate a field current control signal to maintain the magnetic flux of the synchronous generator 112 constant based on the magnetic flux estimation result, and the field current control signal can include the field current reference value. As a result, the magnetic flux of the stator of the synchronous generator 112 is maintained at a constant magnetic flux, and based on this, the voltage can be controlled to a constant value. The constant magnetic flux may be a predetermined specific value or a value within a predetermined range. Furthermore, in this specification and claims, "maintaining a constant magnetic flux" may be interpreted as including "maintaining within a certain range." The AVR 113 can be configured with the same hardware as the AVR 113 used in a typical AC generator.

[0056] The AVR 113 can be divided into a field current regulator (FCR) mode and an automatic voltage regulator (AVR) mode depending on the control method. The AVR mode automatically controls the voltage of the generator, while the FCR mode manually controls the current of the generator. The AVR mode controls the terminal voltage of the generator, while the FCR mode controls the field current of the generator. Typically, the AVR mode controls the terminal voltage of the generator. However, in one embodiment of the present invention, a field current regulator (FCR) control mode capable of controlling the field current of the generator can be applied. The AVR 113 can control the magnetic flux of the synchronous generator 112 to a constant value and the voltage to a constant value using the FCR control mode capable of controlling the field current. When the AVR 113 operates in the FCR control mode, the magnetic flux is controlled using the field current, allowing the output terminal voltage and the field current to be controlled independently.

[0057] Referring to FIG. 6, the AFE converter 111 may include a voltage controller 111a, a current controller 111b, a phase locked loop (PLL) 111c, a magnetic flux controller 111d, a PWM controller 111e, and a magnetic flux estimator 111f.

[0058] The voltage controller 111a controls a current reference value ( TIFF2025535987000002.tif97) can be calculated. The output terminal of the AFE converter 111 may represent a DC switch board (160 in FIG. 4). The current reference value ( TIFF2025535987000003.tif97) is the reference voltage ( TIFF2025535987000004.tif57) and the voltage of the DC switchboard (160 in Figure 4) ( TIFF2025535987000005.tif57). TIFF2025535987000006.tif57) can be the target voltage that the DC switchboard (160 in FIG. 4) should maintain constant. TIFF2025535987000007.tif97) can be the Q-axis current reference value in a stationary reference frame.

[0059] The current controller 111b controls the current reference value ( TIFF2025535987000008.tif97) and the actual current value at the output end of the synchronous generator 112 ( TIFF2025535987000009.tif77) to obtain the voltage reference value ( TIFF2025535987000010.tif67) can be calculated. TIFF2025535987000011.tif67) can be a value required to control the power of the DC switchboard (160 in FIG. 4). The actual current value ( TIFF2025535987000012.tif77) can be a value converted to reflect the rotor angle estimated by the phase locking circuit 111c.

[0060] The phase-locked circuit 111c can estimate the rotor angle of the synchronous generator 112. The phase-locked circuit 111c can estimate the rotor angle using the magnetic flux estimated by the magnetic flux estimator 111f. For example, the phase-locked circuit 111c can estimate the rotor angle by performing a rotational transformation on the estimated magnetic flux. The phase-locked circuit 111c can input the estimated rotor angle to the magnetic flux estimator 111f.

[0061] The magnetic flux estimator 111f receives a voltage reference value ( TIFF2025535987000013.tif67). The magnetic flux estimator 111f can receive the voltage reference value ( TIFF2025535987000014.tif67) and the phase angle applied voltage ( TIFF2025535987000015.tif57). The magnetic flux estimator 111f can calculate the phase angle applied voltage ( TIFF2025535987000016.tif57) can be converted to abc phase, and the converted phase angle applied voltage ( TIFF2025535987000017.tif57) can be input to the PWM controller 111e.

[0062] The magnetic flux estimator 111f can estimate the magnetic flux of the stator of the synchronous generator 112. The magnetic flux estimator 111f can estimate the magnetic flux using the rotor angle estimated by the phase locking circuit 111c. More specifically, the magnetic flux estimator 111f can estimate the magnetic flux by using the phase angle application voltage ( TIFF2025535987000018.tif57) can be integrated to calculate the magnetic flux. The magnetic flux can be a D-axis magnetic flux with respect to a stationary reference frame of the stator of the synchronous generator 112. The magnetic flux estimator 111f can input the estimated magnetic flux to the phase-locked circuit 111c and the magnetic flux controller 111d.

[0063] The magnetic flux estimator 111f calculates the output current ( TIFF2025535987000019.tif47) can be converted by applying the rotor angle estimated by the phase locking circuit 111c and input to the current controller 111b. As a result, the current controller 111b can convert the output current ( TIFF2025535987000020.tif77) is used to calculate the voltage reference value ( TIFF2025535987000021.tif67) can be calculated.

[0064] The flux controller 111d determines the phase angle applied voltage ( TIFF2025535987000022.tif57) based on the magnetic flux control signal ( TIFF2025535987000023.tif96) can be generated. TIFF2025535987000024.tif96) contains a reference value of the field current required to maintain the magnetic flux of the synchronous generator 112 constant. TIFF2025535987000025.tif96) can be a current signal. The flux controller 111d generates a flux control signal ( TIFF2025535987000026.tif96) can be output to AVR113.

[0065] The PWM controller 111e can synthesize a DC voltage using the voltage reference value output from the current controller 111b and the rotor angle estimated by the phase locking circuit 111c. The PWM controller 111e synthesizes a DC voltage using the converted phase angle application voltage ( TIFF2025535987000027.tif47) can be converted into DC voltage and output to the DC switch board (160 in Figure 4).

[0066] Referring to FIG. 7, the AVR 113 may include a field current regulator 113a and a pilot exciter 113b.

[0067] The field current controller 113a may receive a flux control signal from the flux controller 111d of the AFE converter 111. The flux control signal may include a field current reference value that maintains the magnetic flux of the generator at a constant magnetic flux. The field current controller 113a may transmit the flux control signal to the pilot exciter 113b.

[0068] The pilot exciter 113b may generate a field current control signal based on the magnetic flux control signal received from the field current controller 113a. The field current control signal may include a field current command value. The field current control signal may include an up / down value for controlling the field current of the synchronous generator 112. The up / down value may be a value representing the amount of change in the field current. The pilot exciter 113b may output a field current control signal to the synchronous generator 112 so that the magnetic flux of the synchronous generator 112 is constant.

[0069] Referring to FIG. 8, a DC propulsion marine system 100 according to one embodiment of the present invention may include the AFE converter 111, synchronous generator 112, and AVR 113 described with reference to FIGS. 4 to 6, and may further include a load end 120 and a DC switchboard 160.

[0070] FIG. 9 is a graph showing the electrical characteristics of the generator for marine propulsion according to one embodiment of the present invention, and FIG. 10 is a graph showing the field current of the generator for marine propulsion according to one embodiment of the present invention.

[0071] 9 and 10 together with FIG. 6, the control signal (V sf dqs ) can be as follows:

[0072] (Formula 1) TIFF2025535987000028.tif77103

[0073] Here, ds and qs control the D-axis current to "0" in a stationary reference frame, and the Q-axis current is used to control the DC link voltage.

[0074] dsf^-qsf^ and de-qe are the stator flux (λ^) using the estimated stator flux reference frame. s dqs ) can be estimated and controlled.

[0075] A phase-locked loop (PLL) 111c estimates the angle of the rotor of the generator, and can control the magnetic flux with the estimated angle value.

[0076] Ls is the stator leakage inductance, and Lm is the mutual inductance, which are generator parameter constants, and the magnetic flux can be fixed and controlled by adjusting the magnitude of the field current.

[0077] FIG. 11 illustrates an exemplary computing environment in which a converter for a marine propulsion power plant according to an embodiment of the present invention may be implemented.

[0078] 11, an example system 1000 is shown that includes a computing device 1100 configured to implement one or more of the above-described embodiments. For example, the computing device 1100 may include, but is not limited to, a personal computer, a server computer, a handheld or laptop device, a mobile device (such as a mobile phone, PDA, or media player), a multiprocessor system, a consumer electronics device, a minicomputer, a mainframe computer, a distributed computing environment that includes any of the foregoing systems or devices, and the like.

[0079] The computing device 1100 may include at least one processing unit 1110 and memory 1120. Here, the processing unit 1110 may include, for example, a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., and may have multiple cores. The memory 1120 may be volatile memory (e.g., RAM, etc.), non-volatile memory (e.g., ROM, flash memory, etc.), or a combination thereof.

[0080] Computing device 1100 may also include additional storage 1130. Storage 1130 may include, but is not limited to, magnetic storage, optical storage, etc. Storage 1130 may store computer-readable instructions for implementing one or more embodiments described herein, as well as other computer-readable instructions for implementing an operating system, application programs, etc. The computer-readable instructions stored in storage 1130 may be loaded into memory 1120 for execution by processing unit 1110.

[0081] The computing device 1100 may also include input devices 1140 and output devices 1150. The input devices 1140 may include, for example, a keyboard, a mouse, a pen, a voice input device, a touch input device, an infrared camera, a video input device, or any other input device. The output devices 1150 may include, for example, one or more displays, speakers, a printer, or any other output device. The computing device 1100 may also use input devices or output devices provided in other computing devices as the input devices 1140 or the output devices 1150.

[0082] Computing device 1100 may also include communication connection(s) 1160 that enable it to communicate with other devices (e.g., computing device 1300) over network 1200. Here, communication connection(s) 1160 may include a modem, a network interface card (NIC), an integrated network interface, a radio frequency transmitter / receiver, an infrared port, a USB connection, or other interface for connecting computing device 1100 to other computing devices. Also, communication connection(s) 1160 may include a wired connection or a wireless connection.

[0083] The components of the computing device 1100 described above may be connected by various interconnections such as buses (e.g., Peripheral Component Interconnect (PCI), USB, firmware (IEEE 1394), optical bus structures, etc.), or may be interconnected by a network.

[0084] As used herein, terms such as "converter," "active front-end converter," "voltage controller," "current controller," "phase-locked loop (PLL)," "flux controller," "PWM controller," and "peripheral circuitry" generally refer to hardware, a combination of hardware and software, software, or a computer-related entity that is running software. For example, a "converter," "active front-end converter," "voltage controller," "current controller," "phase-locked loop (PLL)," "flux controller," "PWM controller," and "peripheral circuitry" may represent, but are not limited to, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and / or a computer. For example, both an application running on a controller and the controller may be a component. One or more components may reside within a process and / or thread of execution, and a component may be localized on one computer or distributed among two or more computers.

[0085] As described above, according to the present invention, the variable speed range can be expanded, the transient response is, for example, ±5%, enabling stable voltage control, and the system space can be easily secured by removing the filter and encoder.

[0086] FIG. 12 is a flowchart showing a control method for a DC propulsion marine power generating apparatus according to one embodiment of the present invention.

[0087] Referring to FIG. 12, in step S1010, the synchronous generator 112 can generate an AC voltage.

[0088] Then, in step S1020, an active front end (AFE) converter can convert the AC voltage into a DC voltage.

[0089] Also, in step S1030, the AFE converter 111 can estimate the stator flux and rotor angle of the synchronous generator.

[0090] Then, in step S1040, the Automatic Voltage Regulator (AVR) 113 can control the field current based on the stator magnetic flux and rotor angle of the synchronous generator 112 so that the stator magnetic flux is maintained at a constant magnetic flux.

[0091] In addition, a method for controlling a generator for a DC propulsion marine vessel according to an embodiment of the present invention may include the steps of: a voltage controller 111a calculating a current reference value for maintaining a DC voltage at an output end of the AFE converter 111 at a constant voltage; a current controller 111b calculating a voltage reference value using the current reference value and a current value at an output end of the synchronous generator 112; and a magnetic flux estimator 111f estimating a magnetic flux of a stator of the synchronous generator 112.

[0092] The step of controlling the field current may further include a step of a phase locked circuit 111c estimating a rotor angle of the synchronous generator 112, a step of a flux controller 111d generating a flux control signal including a reference field current value and transmitting the generated flux control signal to an Automatic Voltage Regulator (AVR) 113 so that the magnetic flux of the synchronous generator 112 is maintained at a constant magnetic flux, and a step of the AVR 113 controlling the field current using the reference field current value so that the magnetic flux of the stator of the synchronous generator 112 is maintained at a constant magnetic flux.

[0093] The present invention is not limited to the above-described embodiments and the accompanying drawings. The scope of the rights is limited by the appended claims, and it is obvious to those skilled in the art that various substitutions, modifications, and changes can be made within the scope of the technical idea of ​​the present invention described in the claims.

Claims

1. a synchronous generator for generating an AC voltage; an active front end (AFE) converter connected to an output end of the synchronous generator and converting the AC voltage into a DC voltage.

2. 2. The DC propulsion marine power generating apparatus according to claim 1, further comprising an automatic voltage regulator (AVR) that feedback controls a field current so as to maintain the magnetic flux of the synchronous generator or the output DC voltage of the AFE converter constant.

3. The AFE converter is a magnetic flux estimator for estimating a magnetic flux of a stator of the synchronous generator; 2. The DC propulsion marine power generating apparatus according to claim 1, further comprising: a phase locked loop (PLL) that estimates a rotor angle of the synchronous generator based on the estimated stator magnetic flux.

4. The AFE converter is a voltage controller for calculating a current reference value required to maintain a DC voltage at an output terminal of the AFE converter at a constant voltage; 4. The DC propulsion marine power generating system according to claim 3, further comprising: a current controller for calculating a voltage reference value using the current reference value and a current value at an output end of the synchronous generator.

5. 5. The DC propulsion marine power generating apparatus according to claim 4, wherein the magnetic flux estimator calculates a phase angle application voltage by applying the estimated rotor angle to the voltage reference value, and estimates the magnetic flux by integrating the calculated phase angle application voltage.

6. The AFE converter further includes a PWM controller that converts AC voltage into DC voltage and outputs the DC voltage; 6. The DC propulsion marine power generating apparatus according to claim 5, wherein the magnetic flux estimator converts the phase angle applied voltage into an abc axis and outputs the converted voltage to the PWM controller.

7. the AFE converter further includes a flux controller; 4. The DC propulsion marine power generating apparatus according to claim 3, wherein the magnetic flux controller generates a magnetic flux control signal including a reference field current value based on the estimated stator magnetic flux and transmits the magnetic flux control signal to the AVR.

8. The AVR is 8. The DC propulsion marine power generating apparatus according to claim 7, wherein a field current control signal for controlling a field current is generated based on the magnetic flux control signal, and the field current control signal is output to the synchronous generator.

9. 9. The DC propulsion marine generator set according to claim 8, wherein the field current control signal includes an up / down signal for controlling the field current.

10. The synchronous generator is 2. The DC propulsion marine power generating system according to claim 1, which comprises a wound-type AC synchronous generator.

11. a synchronous generator generating an AC voltage; an active front end (AFE) converter converting the AC voltage into a DC voltage; and feedback controlling a field current by an automatic voltage regulator (AVR) so as to maintain the magnetic flux of the synchronous generator or the output DC voltage of the AFE converter constant.

12. the AFE converter estimating a magnetic flux of a stator of the synchronous generator; 12. The method of claim 11, further comprising the step of: the AFE converter estimating the rotor angle of the synchronous generator based on the estimated stator magnetic flux.

13. calculating a current reference value required for maintaining a DC voltage at an output terminal of the AFE converter at a constant voltage; 13. The method of claim 12, further comprising: the AFE converter calculating a voltage reference value using the current reference value and a current value at an output end of the synchronous generator.

14. The step of estimating the magnetic flux comprises: calculating a phase angle applied voltage by applying the estimated rotor angle to the voltage reference value; 14. The method of claim 13, further comprising the step of: integrating the calculated phase angle applied voltage to estimate magnetic flux.

15. generating a magnetic flux control signal including a reference field current value based on the estimated stator magnetic flux by the AFE converter; 13. The method of claim 12, further comprising the step of: the AFE converter transmitting the flux control signal to the AVR.

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