Power generation device for direct current propulsion ship and control method thereof

Abstract

The purpose of the present invention is to provide a power generation device for direct-current propulsion of a ship based on a direct-current power source and a control method therefor, the power generation device for direct-current propulsion of a ship according to one embodiment of the present invention comprising: a synchronous generator for generating an alternating-current voltage; the active front-end converter is connected to the output end of the synchronous generator and is used for converting the alternating-current voltage into direct-current voltage; and an automatic voltage regulator performing feedback control on an excitation current so that a magnetic flux of the synchronous generator or an output DC voltage of the active front-end converter is maintained constant, 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 generation device for a DC propulsion ship and a control method thereof. Background Art

[0002] Generally, to generate electrical energy consumed by various electrical devices of a ship or the like, a power propulsion system including a generator is used.

[0003] The generated electrical energy is used for propulsion of the ship and various components for ship operation and equipment required to supply power to the system. Also, in a passenger ship, passengers directly or indirectly consume a large amount of electrical energy by using the amenities on board through electrical devices.

[0004] As is well known, an AC power source is generated by a generator connected to a prime mover to supply electrical energy to a ship. The prime mover uses various energy sources such as diesel fuel and fuel oil to generate the rotational motion of the generator. For different purposes, the generated AC power source is converted to an appropriate voltage level.

[0005] Recently, for environmental protection issues and to improve fuel efficiency, a DC-based power propulsion system capable of variable-speed operation of a power generation engine is applied.

[0006] (Patent Document 1) Korean Patent Publication No. 10-194895 Summary of the Invention

[0007] Problems to be Solved

[0008] An object of the present invention is to provide a power generation device for a DC propulsion ship using an AFE converter and a control method thereof.

[0009] Another object of the present invention is to provide a device and a control method for fixing the magnetic flux of a synchronous generator by controlling the excitation current of an AVR using an AFE converter and an FCR mode without a filter and a magnetic flux estimation sensor.

[0010] The objects of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can also be clearly understood by those skilled in the art through the following description.

[0011] Means for Solving the Problems

[0012] To achieve the above object, the present invention provides the following power generation device for a DC propulsion ship.

[0013] A power generation device for a DC propulsion ship according to an embodiment of the present invention includes: a synchronous generator that generates an AC voltage; an active front end (AFE) converter connected to an output end of the synchronous generator to convert the AC voltage into a DC voltage.

[0014] A control method for a power generation device for a DC propulsion ship according to an embodiment of the present invention includes: a step of a synchronous generator generating an AC voltage; and a step of an Active Front End (AFE) converter converting the AC voltage into a DC voltage.

[0015] Advantages of the Invention

[0016] According to an embodiment of the present invention, even without a filter and an encoder, the excitation current can be controlled by using an AFE converter and an AVR in the FCR mode, thereby fixing the magnetic flux of the synchronous generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1a shows an example of an existing DC propulsion ship.

[0018] FIG. 1b shows an example of an existing DC propulsion ship.

[0019] Figure 2 Shows an example of a DC propulsion ship according to an embodiment of the present invention.

[0020] Figure 3 Shows an example of a DC propulsion ship according to an embodiment of the present invention.

[0021] Figure 4 Is a configuration diagram of a system for a DC propulsion ship according to an embodiment of the present invention.

[0022] Figures 5 to 8 Is a schematic configuration diagram of a power generation device for a DC propulsion ship according to an embodiment of the present invention.

[0023] Figure 9 Is a diagram showing the electrical characteristics of a power generation device for ship propulsion according to an embodiment of the present invention, and FIG. 10 is a diagram showing the excitation current of a power generation device for ship propulsion according to an embodiment of the present invention.

[0024] Figure 11 Is a diagram showing an exemplary computing environment of a converter capable of implementing a power generation device for ship propulsion according to an embodiment of the present invention.

[0025] Figure 12 Is a flowchart showing a control method for a power generation device for a DC propulsion ship according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art having ordinary knowledge in the relevant field can easily implement it. However, when the detailed description of related known functions or configurations is considered to unnecessarily obscure the gist of the present invention during the detailed description of the preferred embodiments of the present invention, the detailed description thereof will be omitted. In addition, in all the drawings, the same reference numerals are used for parts having similar functions and actions.

[0027] In addition, throughout the specification, when a component is described as being 'connected' to another component, it includes not only the case of 'direct connection' but also the case of 'indirect connection' through other elements therebetween. In addition, unless otherwise specifically stated to the contrary, 'including' a certain constituent element should be understood as also including other constituent elements, rather than excluding other constituent elements.

[0028] The present invention can be implemented in various different forms and is not limited to the embodiments described herein.

[0029] FIG. 1 shows an example of the power generation end of an existing DC propulsion ship.

[0030] FIG. 1a shows an example of an existing DC propulsion ship.

[0031] Referring to FIG. 1a, an existing AC propulsion ship 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.

[0032] Generally, since existing ships mainly use alternating current as the main power distribution, in order to convey the AC voltage output from the generator 11 to the switchboard, no separate converter is required. Therefore, the AC voltage generated from the generator 11 is directly connected to the AC switchboard to supply voltage to the load end or the propulsion motor end. At this time, in order to improve energy efficiency, a converter 17 (AFE or DFE) for converting the AC voltage into a DC voltage and an inverter 18 for converting the DC voltage into an AC voltage can be used together at the propulsion motor end. In addition, the AVR 13 can perform the function of stabilizing the voltage of the AC power generated by the generator 11.

[0033] FIG. 1b shows an example of an existing DC propulsion ship.

[0034] Referring to FIG. 1b, an existing DC propulsion ship 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.

[0035] The generator 11 can generate an alternating voltage, and the DFE converter 12 can convert the alternating voltage generated from the generator 11 into a direct current voltage. Also, the automatic voltage regulator 13 can perform constant automatic control on unstable voltage fluctuations to provide an equal output voltage, and is generally used for alternating voltages. The governor 15 can control the rotational speed of the engine, and the PEMS 16 can control the overall power system of the ship.

[0036] The PEMS 16 can be connected to the DC distribution board of the DC propulsion ship 2, and can convey commands to the governor 15 that controls the engine 14 to control the engine.

[0037] In the power generation end of the DC propulsion ship 1, a converter that converts the alternating current generated from the generator 11 into direct current is essential, and the DFE converter 12 is generally used in the power generation end of the existing DC propulsion ship 1.

[0038] However, although the DFE converter 12 has the advantages of simple circuit structure and low cost, since the PEMS 16 cannot independently control the DFE converter 12, precise control cannot be achieved, and since the engine variable speed control and the generator voltage control are coupled, the control method is complex, and due to the limitations of DC voltage control, there is a problem of reduced system stability.

[0039] Figure 2 An example of the power generation end of a DC propulsion ship according to an embodiment of the present invention is shown.

[0040] Reference Figure 2 Referring to FIG., in the DC propulsion ship 3, an Active Front End (AFE) converter 23 can be used to replace the DFE converter. Accordingly, the DC propulsion ship 3 can include a generator 21, an LCL filter 22b, an Active Front End (AFE) converter 23, an AVR 24, and a flux estimation sensor 22a. In addition, the DC propulsion ship 3 can further include an engine 25, a GVR 26, and a PEMS 27.

[0041] The AFE converter 23 controls the power factor at the power generation end to 1, and thus can convert an AC power supply into a DC power supply, and has the advantage of being able to independently control the magnetic flux and DC voltage of the generator 21. Accordingly, different from the DFE converter 12, the engine variable speed control and the generator voltage control are decoupled from each other, so the control method is simple, and the DC voltage control can be easily performed, thereby improving the system stability. In addition, compared with the DFE converter 12, the engine operation range is increased, so the fuel efficiency through variable speed can be improved.

[0042] The AFE converter 23 generates a pulse wave through a PWM switching operation. However, the existing control method applicable to the AVR, as the AVR mode (Automatic Voltage Regulator Mode), can be applicable to the case where the output voltage at the power generation end is a sine wave. Therefore, an LCL filter 22b for converting the pulse wave into a sine wave is required.

[0043] However, when using the LCL filter 22b, not only will the system volume increase, but also power loss and loss due to cooling may occur. Especially in a DC propulsion system where it is expected to improve the efficiency through the variable speed of the power generation engine, since the frequency and voltage change with the engine speed, it is impossible to achieve the optimal filter design and control. Therefore, it is necessary to omit the LCL filter 22b.

[0044] In addition, in order for the AFE converter 23 to estimate the magnetic flux of the stator of the generator 21, it is necessary to obtain the rotation position (Position) and rotation speed (RPM) information of the generator (rotating machine). For this purpose, sensors such as an encoder are usually adopted. And the rotation position and speed information of the generator obtained by the sensor are input through the input of the AFE converter 23, but it has the disadvantage of being vulnerable to noise in a converter that switches in the high-frequency region. And when the connection cable is damaged, the system will not be able to operate. Therefore, it is necessary to omit the magnetic flux estimation sensors such as the encoder.

[0045] In addition, in medium and small-sized ships, due to the limited space, it is necessary to reduce the volume of the power generation end by removing the encoder and the filter.

[0046] Figure 3 An example of a DC propulsion ship according to an embodiment of the present invention is shown.

[0047] In an embodiment of the present invention, an AFE converter is used instead of a DEF converter. Since the DFE converter has the engine variable speed control and the generator voltage control coupled, the control method is complex, and there are limitations in DC voltage control, resulting in reduced system stability. In contrast, since the AFE converter has the engine variable speed control and the generator voltage control decoupled, the control method is simple and DC voltage control is easy.

[0048] Referring Figure 3 , in the DC propulsion ship 4 according to an embodiment of the present invention, the AVR operates not in the AVR mode but in the FCR mode (Field Current Regulator Mode), so the flux estimation sensor 22a and the LCL filter 22b can be omitted. Figure 2 .

[0049] Referring Figure 2 , as described above, when the AVR operates in the AVR mode, the AVR generates a command voltage through the PWM (pulse width modulation) switching of active devices, so harmonic components generated by the switching will occur. Therefore, an LCL filter 22b is required to filter out the noise and convert it into a sine wave.

[0050] On the contrary, when the AVR 24 operates in the FCR mode (Field Current Regulator Mode), the command is calculated from the excitation current and transmitted to the AVR, so the LCL filter 22b can be omitted. Accordingly, the operating efficiency of the power generation end of the DC propulsion ship 2 is improved, and the volume of the power generation end can be reduced. In addition, the AFE converter 23 can generate a flux control signal by estimating the angle of the rotor and the stator flux of the generator 21, so a sensorless system without using an encoder can be applied. Therefore, a power generation device for a DC propulsion ship and its control method are proposed, which are not only less affected by noise, but also have no risk caused by cable loss, and can also fix the flux of the generator.

[0051] Figure 4 is a configuration diagram of a system for a DC propulsion ship according to an embodiment of the present invention.

[0052] Referring Figure 4 , the system 100 for a DC propulsion ship according to an embodiment of the present invention may include: a power generation device 110 for a DC propulsion ship, a load end 120, a battery system 130, a motor load end 140, a bus coupler 150, and a DC distribution board 160.

[0053] The power generation device 110 for DC propulsion ships generates an AC power supply and converts it into a DC power supply, and can supply power to the required components through the DC distribution board 160.

[0054] The load terminal 120 can receive the DC power supply through the DC distribution board 160 to perform preset operations.

[0055] The battery system 130 can receive or supply the DC power supply through the DC distribution board 160 for charging and discharging.

[0056] The motor load terminal 140 can receive the DC power supply through the DC distribution board 160, convert it into an AC power supply, and then drive the motor for propelling the ship, etc.

[0057] There can be multiple of the above-mentioned power generation device 110, load terminal 120, battery system 130, and motor load terminal 140 for DC propulsion ships. The DC distribution board 160 can supply the DC power supply of the power generation device 110 for DC propulsion ships to the load terminal 120, battery system 130, and motor load terminal 140 respectively. And, the bus coupler 150 is provided between the DC distribution boards 160, so when an abnormal situation such as a failure occurs, the power transmission can be cut off.

[0058] The present invention described below relates to the power generation device 110 for DC propulsion ships and its control method, and proposes a configuration and control method that gives play to the advantages of DC propulsion and efficiently performs the variable speed operation of the engine.

[0059] Figures 5 to 8 It is a schematic configuration diagram of the power generation device for DC propulsion ships according to an embodiment of the present invention.

[0060] Reference Figure 5 According to

[0061] The AFE converter 111 is connected to the output terminal of the synchronous generator 112 to control the power factor to "1", and thus can convert the AC power output from the synchronous generator 112 into DC power. Different from a general Diode FrontEnd (DFE) type rectifier, the AFE converter 111 can independently control the flux of the generator and the DC power supply.

[0062] The AFE converter 111 of the present invention can estimate the flux of the stator of the synchronous generator 112, generate a flux control signal for controlling the stator flux to be fixed, and transmit it to the AVR 113. The AVR 113 can control the excitation current of the synchronous generator 112 according to the flux control signal. The flux control signal may include an excitation current reference value.

[0063] According to an embodiment of the present invention, the AFE converter 111 estimates the flux and can output a flux control signal, so a sensor for estimating the rotational speed (rpm) of the synchronous generator can be omitted. The flux estimation sensor may include an encoder for measuring the rotational speed of the rotor of the synchronous generator.

[0064] The synchronous generator 112, as a synchronous AC generator that converts mechanical power into power output, may include a stator and a rotor. An armature winding is wound around the stator, and it can be the part for obtaining the organic electromotive force. In addition, an excitation winding is wound around the rotor, which can generate a magnetic field. Moreover, the mechanical rotation of the rotor of the synchronous generator 112 has the same rotation number as the rotating magnetic field of the stator, and the rotational speed can be proportional to the frequency of the current induced to flow in the armature.

[0065] As an embodiment, the synchronous generator 112 may be composed of a Wound Rotor Synchronous Generator (WRSG), and the wound rotor synchronous generator may have a form in which both the rotor and the stator are composed of three-phase windings.

[0066] An automatic voltage regulator (AVR) 113 can control the excitation current to control the magnetic flux of the synchronous generator 112. The AVR 113 can generate an excitation current control signal for controlling the excitation current based on a magnetic flux control signal including an excitation current reference value. To maintain the magnetic flux of the synchronous generator 112 constant, the AVR 113 can generate an excitation current control signal based on the estimated magnetic flux result, and the excitation current control signal can include an excitation 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 the voltage can be controlled to be constant based on this. The constant magnetic flux can be a preset specific value or a value within a preset range. In addition, maintaining constant as described in this specification or claims should be interpreted to include maintaining within a certain range. The AVR 113 can be composed of the same hardware as the AVR 113 used in a normal AC power generation device.

[0067] According to the control mode, the AVR 113 can be divided into a FCR mode (Field Current Regulator Mode) and an AVR mode (Automatic Voltage Regulator Mode). The AVR mode can be a mode of automatically controlling the voltage of the generator, and the FCR mode can refer to a control method of manually controlling the generator current. The AVR mode is a mode of controlling the terminal voltage of the generator, and the FCR mode can refer to a mode of controlling the excitation current of the generator. Generally, the AVR mode of controlling the terminal voltage of the generator can be applied. However, in an embodiment of the present invention, a field current regulator (FCR) control mode capable of controlling the excitation current of the generator can be applied. The AVR 113 adopts the FCR control mode that can control the excitation current to constantly control the magnetic flux of the synchronous generator 112 and can control the voltage to be constant. Since the AVR 113 uses the excitation current to control the magnetic flux when operating in the FCR control mode, the output terminal voltage and the excitation current can be independently controlled.

[0068] Reference Figure 6 , the AFE converter 111 can 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.

[0069] The voltage controller 111a can calculate a current reference value for maintaining the DC voltage at the output terminal of the AFE converter 111 as a constant voltage The output terminal of the AFE converter 111 can refer to the DC distribution board ( Figure 4 160 in). The current reference value It can be calculated by referring to the voltage and the voltage (V Figure 4 in the DC distribution board ( dc ) of 160). The reference voltage can be the target voltage of the DC distribution board ( Figure 4 ) of 160 that needs to be maintained constant. The current reference value can be the Q-axis current reference value in the Stationary Reference Frame.

[0070] The current controller 111b can utilize the current reference value and the actual current value at the output of the synchronous generator 112 to calculate the voltage reference value The voltage reference value can be the value required to control the power supply of the DC distribution board ( Figure 4 ) of 160. The actual current value at the output of the synchronous generator 112 used in the current controller 111b can be the value transformed by reflecting the angle of the rotor estimated from the phase-locked loop 111c.

[0071] The phase-locked loop 111c can estimate the angle of the rotor of the synchronous generator 112. The phase-locked loop 111c can estimate the rotor angle based on the magnetic flux estimated by the magnetic flux estimator 111f. For example, the phase-locked loop 111c can rotate and transform the estimated magnetic flux to estimate the rotor angle. The phase-locked loop 111c can input the estimated rotor angle to the magnetic flux estimator 111f.

[0072] The magnetic flux estimator 111f can receive the voltage reference value from the current controller 111b The magnetic flux estimator 111f can apply the rotor angle estimated by the phase-locked loop 111c to the voltage reference value to calculate the phase angle applied voltage The magnetic flux estimator 111f can convert the phase angle applied voltage to the abc phases, and can input the converted phase angle applied voltage to the PWM controller 111e.

[0073] The magnetic flux estimator 111f can also estimate the magnetic flux of the stator of the synchronous generator 112. The magnetic flux estimator 111f can estimate the magnetic flux by using the rotor angle estimated by the phase-locked loop 111c. More specifically, the magnetic flux estimator 111f can pass through the phase angle voltage applied by the rotor angle estimated by the phase-locked loop 111c Integrate to calculate the magnetic flux. The magnetic flux can be the D-axis magnetic flux in the 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 loop 111c and the magnetic flux controller 111d.

[0074] The magnetic flux estimator 111f applies the angle of the rotor estimated by the phase-locked loop 111c to the output current (I abc ) of the synchronous generator for transformation, and can be input to the current controller 111b. Therefore, the current controller 111b can use the output current of the synchronous generator to which the estimated rotor angle is applied to calculate the voltage reference value reflecting the estimated angle of the rotor of the synchronous generator

[0075] The magnetic flux controller 111d can apply a voltage based on the phase angle to generate a magnetic flux control signal (I f ). The magnetic flux control signal (I f ) can include the reference value of the excitation current required to keep the magnetic flux of the synchronous generator 112 constant. The magnetic flux control signal (I f ) can be a current signal. The magnetic flux controller 111d can output the magnetic flux control signal (I f ) including the excitation current reference value to the AVR113.

[0076] The PWM controller 111e can synthesize a DC voltage by using the voltage reference value output from the current controller 111b and the angle of the rotor estimated from the phase-locked loop 111c. The PWM controller 111e can also apply the converted phase angle voltage to convert it into a DC voltage and output it to the DC distribution board ( Figure 4 of 160).

[0077] Reference Figure 7 , the AVR113 can include a field current regulator 113a and a pilot exciter 113b.

[0078] The field current regulator 113a can receive the magnetic flux control signal from the magnetic flux controller 111d of the AFE converter 111. The magnetic flux control signal can include the reference value of the excitation current that keeps the magnetic flux of the generator constant. The field current regulator 113a can convey the magnetic flux control signal to the pilot exciter 113b.

[0079] The pilot exciter 113b may generate an excitation current control signal based on the magnetic flux control signal received from the excitation current regulator 113a. The excitation current control signal may include an excitation current command value. The excitation current control signal may also include an increase / decrease value for controlling the excitation current of the synchronous generator 112. The increase / decrease value is a value that can represent the amount of change in the excitation current. The pilot exciter 113b may output an excitation current control signal to the synchronous generator 112 so that the magnetic flux of the synchronous generator 112 is constant.

[0080] refer to Figure 8 According to an embodiment of the present invention, a system 100 for DC propulsion of a ship may include: Figures 4 to 6 The described AFE converter 111 , synchronous generator 112 and AVR 113 may also include a load end 120 and a DC switchboard 160 .

[0081] Figure 9 is a graph showing electrical characteristics of a power generation device for ship propulsion according to an embodiment of the present invention, Figure 10 1 is a diagram showing an exciting current of a power generation device for ship propulsion according to an embodiment of the present invention.

[0082] and Figure 6 Reference together Figure 9 and Figure 10 , the control signal of the current controller 111b (V sf dqs ) can be shown as the following formula 1:

[0083] (Formula 1)

[0084]

[0085] Among them, ds and qs are D-axis currents in a stationary reference frame, which are controlled to be “0”, and Q-axis currents are used to control the DC link voltage.

[0086] dsf^-qsf^ and de-qe can use the estimated stator flux reference frame to estimate and control the stator flux (λ^ sdqs ).

[0087] A phase locked loop (PLL) 111c estimates the angle (angle) of the rotor of the generator and can control the magnetic flux based on the estimated angle value.

[0088] Ls is the stator leakage inductance, and Lm is the mutual inductance. They are generator parameter constants and the magnetic flux can be controlled to be constant by adjusting the magnitude of the excitation current.

[0089] Figure 11 FIG. is a diagram showing an exemplary computing environment of a converter of a power generation device for ship propulsion according to an embodiment of the present invention.

[0090] Referring to Figure 11 , an example of a system 1000 including a computing device 1100 configured to implement one or more of the above embodiments is shown. For example, the computing device 1100 may include a personal computer, a server computer, a handheld or notebook device, a mobile device (such as a mobile phone, a PDA, a media player, etc.), a multi-processor system, a consumer electronic device, a minicomputer, a mainframe computer, a distributed computing environment including any of the above systems or devices, etc., but is not limited thereto.

[0091] The computing device 1100 may include at least one processing unit 1110 and a memory 1120. Among them, 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 a volatile memory (such as RAM, etc.), a non-volatile memory (such as ROM, flash memory, etc.) or a combination thereof.

[0092] In addition, the computing device 1100 may further include an additional storage device 1130. The storage device 1130 includes a magnetic storage device, an optical storage device, etc., but is not limited thereto. The storage device 1130 may store computer-readable instructions for implementing one or more of the embodiments described in this specification, and may also store other computer-readable instructions for implementing an operating system, an application program, etc. The computer-readable instructions stored in the storage device 1130 may be loaded into the memory 1120 for execution by the processing unit 1110.

[0093] Moreover, the computing device 1100 may include an input device 1140 and an output device 1150. Among them, the input device 1140 may include, for example, a keyboard, a mouse, a stylus, a voice input device, a touch input device, an infrared camera, a video input device, or any other input device, etc. In addition, the output device 1150 may include, for example, more than one display, a speaker, a printer, or other output devices, etc. Moreover, the computing device 1100 may also use the input devices or output devices available on other computing devices as the input device 1140 or the output device 1150.

[0094] In addition, the computing device 1100 may include a communication interface 1160 that is communicable with other devices (such as the computing device 1300) via a network 1200. Among them, the communication interface 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 interfaces for connecting the computing device 1100 to other computing devices. In addition, the communication interface 1160 may include a wired connection or a wireless connection.

[0095] The components of the above computing device 1100 can be connected through various interconnection methods such as a bus (for example, Peripheral Component Interconnect (PCI), USB, FireWire (IEEE 1394), optical bus architecture, etc.), and can also be interconnected through a network.

[0096] The terms "converter", "active front-end converter", "voltage controller", "current controller", "phase-locked loop (PLL)", "flux controller", "PWM controller", and "peripheral circuit" used in this specification generally refer to hardware, a combination of hardware and software, software, or software that is running, that is, a computer-related entity. For example, "converter", "active front-end converter", "voltage controller", "current controller", "phase-locked loop (PLL)", "flux controller", "PWM controller", and "peripheral circuit" can be a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer, but not limited to this. For example, an application program driven on a controller and the controller can both be regarded as components. More than one component can exist in a process and / or an execution thread, and the components can be localized on a single computer or distributed among two or more computers.

[0097] As described above, according to the present invention, the variable speed range can be extended, and stable voltage control of transient response (for example, ±5%) is feasible, and the system space can be easily ensured by eliminating filters and encoders.

[0098] Figure 12 It is a flowchart showing a control method of a power generation device for a DC propulsion ship according to an embodiment of the present invention.

[0099] Refer to Figure 12 , in step S1010, the synchronous generator 112 can generate an alternating voltage.

[0100] Moreover, in step S1020, an Active Front End (AFE) converter can convert the alternating voltage into a direct current voltage.

[0101] Moreover, in step S1030, the AFE converter 111 can estimate the magnetic flux of the stator of the synchronous generator and the angle of the rotor.

[0102] Moreover, in step S1040, an Automatic Voltage Regulator (AVR) 113 can control the excitation current based on the magnetic flux of the stator of the synchronous generator 112 and the angle of the rotor to maintain the magnetic flux of the stator as a constant magnetic flux.

[0103] In addition, the control method of the power generation device for a DC propulsion ship according to an embodiment of the present invention may include: the step of a voltage controller 111a calculating a current reference value in order to maintain the direct current voltage at the output end of the AFE converter 111 as a constant voltage; and the step of a current controller 111b calculating a voltage reference value by using the current reference value and the current value at the output end of the synchronous generator 112; the step of a magnetic flux estimator 111f estimating the magnetic flux of the stator of the synchronous generator 112.

[0104] In addition, the step of controlling the excitation current may further include: the step of a Phase Locked Loop (PLL) 111c estimating the angle of the rotor of the synchronous generator 112; the step of a magnetic flux controller 111d generating a magnetic flux control signal including an excitation current reference value and transmitting it to an Automatic Voltage Regulator (AVR) 113 in order to maintain the magnetic flux of the synchronous generator 112 as a constant magnetic flux; and the step of the AVR 113 controlling the excitation current by using the excitation current reference value in order to maintain the magnetic flux of the stator of the synchronous generator 112 as a constant magnetic flux.

[0105] The present invention is not limited to the above-described embodiments and drawings. The scope of the claims is intended to be limited by the appended claims, and those of ordinary skill in the technical field to which the present invention pertains can make replacements, deformations, and modifications without departing from the technical idea described in the claims of the present invention as a matter of course.

Claims

1. A power generation device for a DC propulsion ship, comprising: A synchronous generator that generates an alternating current voltage; and An active front-end converter connected to the output of the synchronous generator that converts the alternating current voltage into a direct current voltage.

2. The power generation device for a DC propulsion ship according to claim 1, further comprising: An automatic voltage regulator that performs feedback control on the excitation current to keep the magnetic flux of the synchronous generator or the output direct current voltage of the active front-end converter constant.

3. The power generation device for a DC propulsion ship according to claim 1, wherein, The active front-end converter includes: A flux estimator that estimates the magnetic flux of the stator of the synchronous generator; and A phase-locked loop that estimates the angle of the rotor of the synchronous generator based on the estimated magnetic flux of the stator.

4. The power generation device for a DC propulsion ship according to claim 3, wherein, The active front-end converter includes: A voltage controller that calculates a required current reference value to keep the direct current voltage at the output of the active front-end converter at a constant voltage; and A current controller that calculates a voltage reference value using the current reference value and the current value at the output of the synchronous generator.

5. The power generation device for a DC propulsion ship according to claim 4, wherein, The flux estimator applies the estimated angle of the rotor to the voltage reference value to calculate a phase angle applied voltage, and integrates the calculated phase angle applied voltage to estimate the magnetic flux.

6. The power generation device for a DC propulsion ship according to claim 5, wherein, The active front-end converter further includes: A pulse width modulation controller that converts the alternating current voltage into a direct current voltage and outputs it, The flux estimator converts the phase angle applied voltage into the abc axis and outputs it to the pulse width modulation controller.

7. The power generation device for a DC propulsion ship according to claim 3, wherein, The active front-end converter further includes a flux controller, The flux controller generates a flux control signal including an excitation current reference value based on the estimated magnetic flux of the stator, and transmits the flux control signal to the automatic voltage regulator.

8. The power generation device for a DC propulsion ship according to claim 7, wherein, The automatic voltage regulator generates an excitation current control signal for controlling the excitation current based on the flux control signal, and outputs the excitation current control signal to the synchronous generator.

9. The power generation device for a DC propulsion ship according to claim 8, wherein, The excitation current control signal includes: A raise / lower signal that controls the excitation current.

10. The power generation device for a DC propulsion ship according to claim 1, wherein, The synchronous generator is composed of a wound-rotor alternating current synchronous generator.

11. A control method for a power generation device for a DC propulsion ship, comprising: Steps for the synchronous generator to generate an alternating current voltage; Steps for the active front-end converter to convert the alternating current voltage into a direct current voltage; and Steps for performing feedback control on the excitation current through the automatic voltage regulator to keep the magnetic flux of the synchronous generator or the output direct current voltage of the active front-end converter constant.

12. The control method of the power generation device for a DC propulsion ship according to claim 11 further includes: Steps for the active front-end converter to estimate the magnetic flux of the stator of the synchronous generator; and Steps for the active front-end converter to estimate the angle of the rotor of the synchronous generator based on the estimated magnetic flux of the stator.

13. The power generation device for a DC propulsion ship according to claim 12 further includes: Steps for the active front-end converter to calculate a required current reference value to keep the direct current voltage at the output of the active front-end converter at a constant voltage; and Steps for the active front-end converter to calculate a voltage reference value using the current reference value and the current value at the output of the synchronous generator.

14. The power generation device for a DC propulsion ship according to claim 13, wherein, The steps for estimating the magnetic flux include: Steps for applying the estimated angle of the rotor to the voltage reference value to calculate a phase angle applied voltage; and Steps for integrating the calculated phase angle applied voltage and estimating the magnetic flux.

15. The power generation device for a DC propulsion ship according to claim 12 further includes: Steps for the active front-end converter to generate a flux control signal including an excitation current reference value based on the estimated magnetic flux of the stator; and The step in which the active front-end converter transmits the flux control signal to the automatic voltage regulator.

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