TW201841449A - Power distribution system in moving body - Google Patents

Abstract

A power distribution system in a moving body, provided with a first power system connected to a power generator and a first power load in which the amount of power fluctuation is less than a prescribed value, a second power system connected to a second power load in which the amount of fluctuation may reach or exceed the prescribed value, a first power converter, a second power converter, a third power converter, and a bus tie breaker. When the second power load is not operating, the bus tie breaker is in a connected state, and when the second power load is operating, the bus tie breaker is in a cut-off state. The first power converter is controlled on the basis of a first power command value given by a low-frequency component, below a prescribed frequency, of the actual power value of the second power converter. The second power converter is droop-controlled. The power of the third power converter is controlled so as to resolve the imbalance of power flowing into and out from a DC intermediate part.

Description

   Power distribution system for moving objects   

The invention relates to a power distribution system for a mobile body.

Conventionally, for example, a propulsion system for a mobile body such as a ship is known (see Patent Document 1). Recently, from the viewpoint of improving efficiency and reducing maintenance costs by using a generator at a high load, it is desirable to operate the power of a mobile body with only one generator (hereinafter also referred to as a single generator operation).

[Prior technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-55850

However, when it is assumed that the power required for the operation of the conventional moving body propulsion system is provided by a generator, the generator may be tripped due to a rapidly changing electric load (such as a crane, etc.). There is a risk of power outages. Therefore, in the case of using a power load with rapid changes, it is necessary to operate an additional generator.

Alternatively, instead of the additional generator, the power storage device may be connected to the power system through a power conversion device, and the power generator and the power storage device may share the amount of power fluctuation. However, in order for the power storage device to share most of the amount of variation, it is necessary to install electric power measurement means at each load to obtain the amount of variation, and to control the power of the power conversion device at high speed before the motor system of the generator responds.

The present invention has been completed in order to solve the problems as described above, and the purpose thereof is to use a simple method to operate a power system of a mobile body even when a power load with sharp changes is used. .

In order to achieve the above-mentioned object, a power distribution system for a mobile body of a certain form of the present invention includes a first power system connected to a generator driven by a prime mover, and a variation in power consumed by a load or regenerated from the load ( (Hereinafter referred to as power load variation) a first power load that does not reach a predetermined value; a second power system that is connected to a second power load whose power load variation can become above the predetermined value; a first power converter whose AC end is connected In the first power system, and its DC terminal is connected to the DC intermediate section; in the second power converter, the AC terminal is connected to the second power system, and its DC terminal is connected to the DC intermediate section; the third power converter And its two DC ends are respectively connected to the above-mentioned DC intermediate part and the power storage device; and a bus tie breaker, which constitutes a path connected in parallel with the power supply path, which is from the first power system through the first power converter And the second power converter reaches the second power system; and the bus tie breaker is connected when the second power load is not running. On the other hand, the second power load is set to a blocking state during the operation of the second power load. The first power converter is based on a low-frequency component that is lower than a predetermined frequency in the actual power value of the second power converter. The first electric power command value is controlled, the second electric power converter is controlled by droop control, and the third electric power converter is controlled to eliminate the imbalance of electric power flowing into or out of the DC intermediate section.

According to the above configuration, when the power load variation (for example, the time change rate of the power, the amplitude of a predetermined frequency component of the power, or the step-like power variation amount) can be changed to a second power load operation that exceeds the predetermined value, , Open the bus communication breaker, and set the blocking state between the first power system and the second power system. As a result, in the first power system, the power is directly supplied from the generator to the first power load. On the other hand, the first power system passes through the first power converter and the second power converter to reach the second power system. The power supply path supplies power to a second power load. The power of the second power converter is changed according to the operating condition of the load. On the other hand, the flow of power from the generator to the DC intermediate portion is controlled by the first power converter. The third power converter is controlled so as to absorb a difference in power flowing into or out of the DC intermediate portion. Thereby, the power difference between the first power converter and the second power converter is automatically absorbed by the power storage device. When a sudden load change occurs in the second power load, the second power converter is controlled to droop, so that it is possible to continue to supply power to the second power load. In addition, the first power converter is controlled based on the first power command value given by the low-frequency component of the second power converter's power efficiency value that does not reach a predetermined frequency. Therefore, only the power load variation has not been reached. The low frequency component of the predetermined frequency appears in the form of electric power fluctuation of the first power system, and the frequency component above the predetermined frequency is absorbed by the power storage device under the control of the third power converter. Thereby, the load variation of the generator engine is suppressed, and it is possible to prevent the generator from tripping due to the sudden load variation. In this way, the magnitude of the load variation of the generator engine can be set only by adjusting the predetermined frequency, so the control adjustment is easy, and there is no need to set electric power measurement means at each load.

On the other hand, when the second power load is not running, the bus communication breaker is closed, and the first power system and the second power system are connected. Thereby, a path connected in parallel to the power supply path is formed, and the power supply path reaches the second power system from the first power system through the first power converter and the second power converter. Since the second power converter is controlled to droop, it can be operated in conjunction with a generator (first power system). That is, when it is convenient for a generator to fail, the effect of droop control can also be used to supply power from the power storage device without causing a power outage. Therefore, no matter whether there is a sudden change in the operation of the electric load, the electric system of the moving body can be operated by a generator.

It is also possible that the power distribution system of the mobile body performs droop control on the second power converter so as to become a point on the droop characteristic line, and the droop characteristic line indicates the frequency of the second power system and the frequency of the second power converter. For the relationship of the actual power value, when the second power system is blocked from the first power system, the droop characteristic line is adjusted by setting the frequency of the second power system to a standard frequency. When the second electric power system is connected to the first electric power system, the electric power of the second electric power converter is adjusted to 0 kW, and the frequency of the second electric power system is adjusted to a standard frequency.

According to the above configuration, the second power converter is controlled to sag so as to be a point on the sag characteristic line. This sag characteristic line represents the relationship between the frequency of the second power system and the actual power value of the second power converter. When the second power system including the second power load is blocked from the first power system to which the generator is connected, the frequency of the second power system changes in accordance with the drastic change of the droop characteristic line with respect to the second power load. That is, the second power converter can function in the same manner as a generator when it is operated independently. Further, similar to the generator, the droop characteristic line can be adjusted such that the frequency after the fluctuation is set as the standard frequency.

On the other hand, when the second power system is connected to the first power system, the second power converter is operated in parallel with the generator, and the load sharing ratio of the stable load can be adjusted by adjusting the droop characteristic line. In particular, when the stable load sharing rate of the second power converter is set to 0% (electric power 0 kW), the generator assumes 100% of the power consumed by the load in a steady state. This makes it possible to suppress a loss caused by the second power converter. On the other hand, when the power load has been changed, both the second power converter and the generator are transiently changed in accordance with the droop characteristic line. Therefore, the second power converter and the generator can share only the fluctuation component of the electric load. At this time, since the second electric load is not already running, there is no problem even if about one and a half of the generator load fluctuation component. Furthermore, even if the generator fails and is disconnected from the first power system, the second power converter can be used to supply power without causing a power outage. The power at this time is supplied from the power storage device. This point indicates that the power storage device can be used as a backup power source through the second power converter and the third power converter during this operation.

The power distribution system of the moving body may further include a fourth power converter connected to the DC intermediate portion, a motor may be connected to the AC end of the fourth power converter, and a propeller may be mounted on a propulsion shaft of the motor.

According to the said structure, it can be applied to the electric propulsion system of a mobile body.

The power distribution system of the moving body may further include a fourth power converter connected to the DC intermediate portion, a motor generator is connected to the AC end of the fourth power converter, and a propulsion shaft of the motor generator is installed. Host and thruster.

According to the above configuration, it can be applied to a hybrid propulsion system for a mobile body.

The first electric power command value may be a low-frequency component that does not reach a predetermined frequency in the actual value of the second power converter and a lower-frequency component that does not reach the predetermined frequency in the actual value of power in the fourth power converter. It is given by the sum of low frequency components.

According to the above configuration, since the first power command value is given by the sum of the low frequency component of the actual value of the second power converter and the low frequency component of the actual value of the power of the fourth power converter, it is possible to suppress the power due to, for example, the electric power of the motor. The impact on the first power system due to changes in load and sudden load changes in the second power load. In particular, when the bus tie breaker is closed without operating the second load that includes a sudden change, the first power command value may be given to only the low-frequency component of the actual power value of the fourth power converter.

The fourth power converter may be controlled based on a fourth power command value, and the fourth power command value may be based on the rotation speed command value of the motor-generator provided from the operation console and the electric power generator. The power command value of the motor-generator obtained by controlling the deviation of the actual number of revolutions of the motor, or the power command value of the motor-generator given from the operation console.

According to the above-mentioned configuration, the rotation speed control or power control value of the motor generator can be performed by the fourth power converter by giving the rotation speed command value or the power instruction value from the operation console.

The charging rate of the power storage device may be calculated based on the current effective value or the electric power effective value of the third power converter, and the first charge may be calculated in order to charge and discharge such that the charging rate falls within a predetermined range. The discharge correction power command value and the fourth charge-discharge correction power command value are obtained by adding the first charge-discharge correction power command value and the first power command value, and adding the fourth charge-discharge correction power command value and the fourth Power command values are added.

The power difference between the first power converter, the second power converter, and the fourth power converter is automatically absorbed by charging and discharging of the power storage device. According to the above configuration, the first charge / discharge correction power command value and the fourth charge / discharge correction power command value are added based on the actual value of the third power converter, thereby realizing the SOC (State of Charge) of the power storage device. control.

According to the present invention, a power system of a mobile body can be operated by a generator.

1‧‧‧Power Conversion Device

2‧‧‧ power storage device

3‧‧‧control device

4‧‧‧Bus contact circuit breaker

5‧‧‧ generator

6‧‧‧ prime mover

7‧‧‧ Electric Load

7a‧‧‧1st electric load (with sudden changes)

7b‧‧‧Second electric load (no sudden changes)

8‧‧‧bus line

8a‧‧‧The first bus line (the first power system)

8b‧‧‧Second bus line (second power system)

9‧‧‧ DC middle

11‧‧‧The first power converter

12‧‧‧ 2nd power converter

13‧‧‧3rd power converter

40‧‧‧Operator

60‧‧‧ Reducer

70‧‧‧host

80‧‧‧ Thruster

90‧‧‧ Motor generator

100‧‧‧ Mobile Power Distribution System

FIG. 1 is a diagram schematically showing a configuration of a mobile body including a power distribution system of the mobile body according to the first embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of the control device of FIG. 1. FIG.

FIG. 3 is a block diagram showing the configuration of the power control section of FIG. 2.

Fig. 4 is a block diagram showing a configuration of a power distribution system of a mobile body when the contact breaker of Fig. 1 is opened.

FIG. 5 is a sag characteristic curve of the sag control of the second power converter used in a single operation.

Fig. 6 is a block diagram showing a configuration of a power distribution system of a mobile body when the contact breaker of Fig. 1 is closed.

FIG. 7 is a sag characteristic curve of the sag control of the second power converter during the interconnection operation.

FIG. 8 is a diagram schematically showing a configuration of a mobile body including a power distribution system of the mobile body according to the second embodiment of the present invention.

FIG. 9 is a block diagram showing the configuration of the control device of FIG. 8. FIG.

Fig. 10 is a block diagram schematically showing an example of the inside of the control device of Fig. 9.

FIG. 11 is a block diagram schematically showing another example inside the control device of FIG. 9.

FIG. 12 is a diagram schematically showing the configuration of a mobile body including a mobile power distribution system according to a third embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the same or equivalent elements are denoted by the same symbols in all drawings, and repeated descriptions are omitted.

(First Embodiment)

FIG. 1 is a diagram schematically showing a configuration of a mobile body including a power distribution system 100 of the mobile body according to the first embodiment of the present invention. As shown in FIG. 1, the mobile power distribution system 100 includes a generator 5, a power load 7, a power conversion device 1, a power storage device 2, an AC bus bar 8, a bus tie breaker 4, a control device 3, And propulsion system 200.

The generator 5 is a main power source that supplies power to the power load 7. The generator 5 uses the prime mover 6 as a driving force to provide electric power for use in a mobile body. If the fluctuation of the electric power is very large, the power supply from the generator 5 may be blocked due to the engine trip.

The power load 7 includes a first power load 7 a and a second power load 7 b connected to the AC bus bar 8. The first electric load 7 a is a device that consumes electric power supplied from the generator 5. The first electric load 7a is provided with a plurality of machines, all of which do not include a load change of a sudden electric power. The first electric load 7a includes devices that operate continuously, such as hotel loads such as ship lighting and air conditioning, and devices that operate for a short time, such as winches and engine start motors of the host 70. The second electric load 7b is a machine that consumes electric power, such as a crane, and has a load fluctuation that includes rapid electric power. These devices are connected to the AC bus 8 respectively. In addition, "including sudden changes" means that various physical quantities related to changes in consumed power, such as the time change rate of electric power, the amplitude of a predetermined frequency component of electric power, or the amount of stepped electric power fluctuation, are above a predetermined value. The so-called "excluding rapid changes" means that these various physical quantities have not reached a predetermined value. The predetermined value can be determined based on the information related to the following performance of the load change as prompted by the engine manufacturer.

The AC busbar 8 is a first busbar 8a connected to the generator 5, the first electric load 7a, and the power conversion device 1, and a second busbar connected to the second electric load 7b and the power conversion device 1. The power supply path constituted by the line 8b. The first bus line 8a and the second bus line 8b are connected or blocked by the bus linking the circuit breaker 4. The bus tie breaker 4 is set to the connected state when the second electric load 7b is not running, and is set to the blocked state when the second electric load 7b is running. In this embodiment, the opening and closing of the bus tie breaker 4 is controlled by the control device 3. Hereinafter, in the power distribution system 100 of a mobile body, the power system connected to the first bus line 8a is referred to as a "first power system", and the power system connected to the second bus line 8b is referred to as a "second power system". In other words, the bus communication breaker 4 connects the first power system (8a) and the second power system (8b) in an openable and closable manner, and can form a path connected in parallel to the power supply path, which is from the first power The system (8a) reaches the second power system (8b) via the first power converter 11 and the second power converter 12.

One terminal of the power conversion device 1 is connected to the first power system (8a), and the other terminal thereof is connected to the second power system (8b). Specifically, the power conversion device 1 includes a first power converter 11, a second power converter 12, a third power converter 13, and a DC intermediate section 9.

The first power converter 11 adjusts the power consumed from the first power system (8a). The first power converter 11 is an AC-DC converter. The AC terminal of the first power converter 11 is connected to the first power system (8a), and the DC terminal of the first power converter 11 is connected to the DC intermediate section 9.

The second power converter 12 supplies power to a second power system (8b). The second power converter 12 is an AC-DC converter. The DC terminal of the second power converter 12 is connected to the DC intermediate section 9, and the AC terminal of the second power converter 12 is connected to the second power system (8b).

The third power converter 13 is a DC / DC converter that controls power in order to eliminate the imbalance of the power flowing into or out of the DC intermediate section 9. One DC terminal of the third power converter 13 is connected to the DC intermediate section 9, and the other DC terminal of the third power converter 13 is connected to the power storage device 2.

The DC intermediate section 9 is connected to a DC terminal of the first power converter 11, a DC terminal of the second power converter 12, and a DC terminal of the third power converter 13.

The power storage device 2 is connected to the other DC terminal of the third power converter 13. The power storage device 2 is composed of, for example, a secondary battery and a capacitor. As the secondary battery, for example, a lithium ion battery, a nickel-hydrogen battery, and a lead storage battery can also be used. As the capacitor, for example, a lithium ion capacitor, an electric double-layer capacitor, a nano hybrid capacitor, or a carbon nano tube capacitor can be used.

The power distribution system 100 of this embodiment is applied to a ship equipped with a mechanical propulsion system (hereinafter also referred to as a mechanical propulsion ship). In a mechanically propelled ship, the propulsion system 200 includes a host 70 as a main drive source of the propeller 80. The propeller 80 is a marine propeller. The main engine 70 is configured to be independent from the generator 5 and is configured to drive the thruster 80 only by the thrust of the main engine 70. The configuration of the propulsion system 200A differs depending on the type of the ship equipped with the power distribution system 100A, and examples include hybrid ships, electric propulsion ships, and mechanical propulsion ships equipped with shaft generators.

The control device 3 includes a memory and a computing device (both are not shown), and controls the opening and closing of the power conversion device 1, the bus communication breaker 4, the generator 5, and the propulsion system 200. The control device 3 of this embodiment controls each element of the mobile body in accordance with the operation information from the operation table 40. As shown in the block diagram of FIG. 2, the control device 3 includes a main control unit 30, a power control unit 31, a droop control unit 32, a charge / discharge control unit 33, and a droop control unit 35. Each of these parts has a function realized by executing a program stored in a memory in a computing device. The functions of the power control unit 31, the droop control unit 32, the charge / discharge control unit 33, and the droop control unit 35 may be included in the computing device of the first power converter 11, the computing device of the second power converter 12, Programs for the computing device of the third power converter 13 and the engine control device of the generator 5.

The main control unit 30 selects the operation mode of the propulsion system 200 based on the operation information indicating the position of the lever inputted from the lever provided on the operation table 40, and starts and stops the components of the propulsion system 200, for example. Although the main control unit 30 generates the opening / closing command of the bus communication breaker 4 according to the operation mode of the moving body, for example, the operator may directly open and close the bus communication breaker 4. In addition, a part of the functions of the main control unit 30 may be included in a program of a power management system that manages power supply and demand of a ship. The main control unit 30 can start and stop the generator 5 and can also start and stop the generator 5 from the power management system. The power management system performs adjustment of the droop characteristic line in the droop control described later or management of the actual power value of the power conversion device.

The power control unit 31 is based on the first power command value given by the low-frequency component of the power actual value of the second power converter 12 that does not reach a predetermined frequency, and the power converted by the first power converter 11 becomes the first The power command value controls the first power converter 11. The power control unit 31 includes a filter 311 (see the block diagram of FIG. 3). The filter 311 is a low-pass filter or a moving average filter having a fixed time constant. The autonomous control unit 30 inputs the actual power value of the second power converter 12, and the filter 311 passes only the low-frequency component of the second power converter 12 that does not reach a predetermined frequency, and uses it as the first power The command value is output to the first power converter 11.

The droop control unit 32 performs droop control on the second power converter 12. The “sag control” refers to control in which the second power converter 12 has characteristics equivalent to a generator by constructing a model of a governor that controls the generator within the control device 3. When the second power converter 12 has a characteristic equivalent to a generator, the independent operation and the system interconnection operation can be seamlessly switched. In addition, since "sag control" is a well-known technique, detailed description is omitted. Please refer to "G.Marina & E.Gatti," Large Power PWM IGBT Converter for Shaft Alternator Systems ", 35th Annual IEEE Power Electronics Specialists Conference, 2004" for detailed description of "Sag Control". In the "sag control", each sensor (not shown) detects the frequency of the power system and the power (effective power) that the second power converter 12 transmits to the power system, and inputs it to the droop control unit. 32. Use it for the control of droop control.

The charge / discharge control unit 33 monitors the voltage of the DC intermediate portion 9 based on the sensor data from the voltage sensor and the current sensor (not shown) in the third power converter 13 and uses the DC intermediate portion 9 The charging and discharging control of the power storage device 2 is performed such that the voltage becomes a fixed value. The charge / discharge control unit 33 uses the third power converter 13 to control the charge and discharge of the power storage device 2 in accordance with a change in the voltage of the DC intermediate portion 9. Thereby, the difference between the electric power flowing into the DC intermediate section 9 and the electric power flowing out from the DC intermediate section 9 is absorbed by the power storage device 2.

The droop control unit 35 detects effective power, obtains a frequency target value based on droop characteristics, and performs revolution control of the prime mover (engine, turbine, etc.) of the generator 5. The follow-up speed of the frequency variation with respect to the load variation is determined by mechanical characteristics such as the inertia of the generator.

Next, the operation of the mobile power distribution system 100 will be described. The opening and closing of the bus tie breaker 4 is controlled in accordance with the operation mode of the moving body selected by lever operation of the operation table 40 (see FIG. 2). When the main control unit 30 selects a predetermined operation mode for operating the second electric load 7 b (for example, a crane), it generates an open command of the bus tie breaker 4 and sends it to the bus tie breaker 4. FIG. 4 is a block diagram showing a configuration of a power distribution system 100 of a mobile body when the bus tie breaker 4 is opened. As shown in FIG. 4, by connecting the circuit breaker 4 with the bus bar, the first power system (8 a) and the second power system (8 b) are blocked. Although in the first power system (8a), power is directly supplied from the generator 5 to the first power load 7a, but since the second power system (8b) is separated from the first power system (8a), The power system (8a) supplies power to the second power load 7b through the first power converter 11 and the second power converter 12.

At this time, the power supplied to the second power system (8b) through the second power converter 12 changes according to the operating condition of the second power load 7b, and according to this change, the frequency of the second power system (8b) also changes. . Specifically, the second power converter 12 is controlled by the droop control unit 32 (see FIG. 2). Hereinafter, a case where the bus tie breaker 4 is opened as shown in FIG. 4 and the second power converter 12 and the generator 5 are operated independently is referred to as a separate operation. In stand-alone operation, the power generation is determined based on the operating conditions of the load. FIG. 5 is a sag characteristic curve of the sag control of the second power converter used in a single operation. As shown in FIG. 5, the droop characteristic is a relationship between the effective power (positive at the time of power generation) and the system frequency, and is set so that the larger the effective power, the lower the system frequency. Sag rate is defined as the difference between the frequency at rated load and the frequency at no load divided by the rated frequency. Generally, although the droop rate is set to the same value in each power source, it may be set to a different value as required. The sag control unit 32 performs sag control on the second power converter 12 so as to be a point on the sag characteristic line, and the sag characteristic line represents the frequency of the second power system (8b) and the actual power value of the second power converter 12 relationship.

FIG. 5 (a) is a sagging characteristic line set in the steady state of the second power converter 12. As shown in FIG. 5 (a), in the steady state, when the second power converter 12 supplies power P1 to the second power system (8b), the droop characteristic line becomes a standard frequency at a frequency corresponding to P1 ( The frequency target value) is set in the manner of Fs (changes into a line crossing the X mark in the figure).

FIG. 5 (b) shows a droop characteristic curve when a sudden load change occurs in the second electric load 7b (for example, a crane). Here, it is assumed that the power supplied from the second power converter 12 to the second power system (8b) increases from P1 to P2 due to a sudden load change. As shown in FIG. 5 (b), the second power converter 12 reduces the frequency of the second power system (8b) in accordance with the drooping characteristic line (marked by (1) on the straight line). Thereafter, the droop characteristic curve of the frequency of the second power system (8b), which has been reduced, should be returned to the standard frequency Fs as a target value by the power management system (direction of arrow of (2)).

FIG. 5 (c) is a droop characteristic line of the second power converter 12 newly set by adjustment from the power management system. As shown in FIG. 5 (c), in the new droop characteristic line, it is set so that the frequency corresponding to P2 becomes the standard frequency (frequency target value) Fs. In this way, even when a sudden load change occurs in the second power load 7b (for example, a crane), the second power converter 12 is controlled to sag, so that the second power converter 12 can be the same as a generator when it is operated independently. To function. Thereby, power can be continuously supplied to the second power load 7b. In the single operation, since the power storage device 2 is an electric power source, unlike the engine generator, load variation cannot be a problem.

On the other hand, the first power converter 11 adjusts the power consumed from the first power system (8a). Specifically, the first power converter 11 is controlled based on the first power command value given by the low-frequency component of the actual power value of the second power converter 12 that does not reach the predetermined frequency, so the predetermined frequency is not reached. The power fluctuation of the low frequency component appears as a load fluctuation in the first power system, and the power fluctuation of the frequency component above a predetermined frequency is absorbed by the power storage device 2. Thereby, the load variation observed from the generator 5 side is suppressed, and tripping of the generator 5 due to a sudden load variation can be prevented.

Next, the operation of the power distribution system 100 when a predetermined operation mode in which the second electric load 7b (for example, a crane) is not operated will be selected. FIG. 6 is a block diagram showing a configuration of a power distribution system 100 of a mobile body in a case where the bus-bar contact breaker 4 is closed. As shown in FIG. 6, the power distribution system 100 connects the circuit breaker 4 to the first power system (8 a) and the second power system (8 b) in a connected state. Thereby, a path connected in parallel with the power supply path is formed, and the power supply path reaches the second power system (8b) from the first power system (8a) through the first power converter 11 and the second power converter 12. Hereinafter, a case where the bus tie breaker 4 is closed and the second power converter 12 and the generator 5 are interconnected and operated is referred to as an interconnected operation. During interconnection operation, the power load sharing rate of the interconnected generators or power converters can be controlled. In addition, the "first power system" and the "second power system" are not distinguished from each other during the interconnection operation, but are simply referred to as "power system". Since the "second electric load 7b" does not operate during the interconnected operation, the "first electric load 7a" and the "second electric load 7b" are not distinguished from each other, but are simply referred to as "electric load".

FIG. 7 is a sag characteristic curve of the sag control of the second power converter during the interconnection operation. The second power converter 12 is controlled to droop so as to be a point on the droop characteristic line indicating the relationship between the frequency of the power system and the actual power value of the second power converter 12. The generator 5 is similarly subjected to droop control so as to become a point on the droop characteristic line.

FIG. 7 (a) is a sagging characteristic line set in a stable state of the second power converter 12 and the generator 5. As shown in FIG. 7 (a), the drooping characteristic line of the second power converter 12 is such that the second power converter 12 does not supply power to the power system in a stable state, with respect to the standard frequency (frequency target value of the power system). ) Fs and set the power command value to 0 kW (× mark on the straight line). On the other hand, the droop characteristic line of the generator 5 is such that the generator 5 supplies power to the power system in a stable state, and is set to the power command value Pc1 (on a straight line) relative to the standard frequency (frequency target value) Fs of the power system (X mark). At present, since the power command value of the second power converter 12 is 0 kW, the above-mentioned Pc1 is consistent with the power of the load consumed by the power system. FIG. 7 (b) shows a droop characteristic curve when a load variation occurs in the electric load 7. Here, it is assumed that the power load is reduced from Pc1 to Pc2. At this time, the operating points of each other change such that the sum of the power generated by the generator 5 and the power generated by the power converter 12 becomes Pc2 in accordance with the drooping characteristic line. As shown in FIG. 7 (b), as the frequency increases, the operating point of the second power converter 12 moves to the mark (1) on the straight line. In this case, the power converter 12 consumes power from the power system. The follow-up speed of the frequency change with respect to the load change is determined by the mechanical characteristics such as the inertia of the generator and the operating characteristics of the power converter. Thereafter, with the power management system, adjustments are made to each of the droop characteristic lines that the frequency of the power system after the rise should return to the standard frequency Fs, and the power of the power converter 12 should return to 0 kW (arrow direction of (2)) .

Fig. 7 (c) is a newly set drooping characteristic curve of the second power converter 12 and the generator 5. Although the droop characteristic line of the second power converter 12 changes transiently, as shown in FIG. 7 (c), the droop characteristic line of the second power converter 12 returns to the original operating point (power command value (0kW)). , The system frequency is the standard frequency Fs). In the new stable state, the generator 5 bears 100% of the power consumed by the load (Pc2). In this way, by adjusting the droop characteristic line so that the power of the second power converter 12 is 0 kW, the second power converter 12 and the generator 5 can share only the fluctuation component of the power load.

In this way, since the second power converter is operated in conjunction with the generator 5 by droop control, even when the generator 5 fails, power can be supplied to the power load 7 without causing a power outage. In this case, the power converter 12 is operated independently, and necessary power can be supplied from the power storage device 2.

Therefore, according to the present embodiment, in the power system of a mobile body, the power supply path to the electric load 7 is switched by using the bus contact breaker 4 to thereby use one unit regardless of whether the electric load 7 has a sudden change in operation. The generator runs the power system of the moving body.

(Second Embodiment)

Next, a second embodiment will be described. The configuration of the mobile power distribution system in this embodiment is the same as that in the first embodiment. Hereinafter, the description of the configuration common to the first embodiment will be omitted, and only the different configuration will be described.

FIG. 8 is a diagram schematically showing a configuration of a mobile body including a power distribution system of the mobile body according to the second embodiment of the present invention. As shown in FIG. 8, the power distribution system 100A is different from the first embodiment (FIG. 1) in that it is applied to a ship equipped with an electric propulsion system. Specifically, the power conversion device 1A further includes a fourth power converter 14 connected to the DC intermediate section 9, and the propulsion system 200A includes a motor generator 90 connected to the AC end of the fourth power converter 14, and a transmission reduction device 60. The propeller 80 is mounted on the propulsion shaft of the motor generator 90.

In an electric propulsion boat, the motor generator 90 functions as a main driving source of the thruster 80. The motor generator 90 receives power from the generator 5 connected to the bus bar 8 through the first power converter 11 and the fourth power converter 14 to generate driving force, and supplies the driving force to the propeller 80 to drive the motor. Thruster 80. Although the motor-generator 90 operates exclusively as an electric motor in an electric propulsion ship, it can also operate as a generator.

The first power converter 11 receives power control based on the first power command value, and the fourth power converter 14 receives power control based on the fourth power command value. The control device 3A includes a power control unit 31 that controls the first power converter 11 and a power control unit 34 that controls the fourth power converter 14 (see a block diagram of Fig. 9).

FIG. 10 is a block diagram schematically showing an example of the inside of the control device 3A. As shown in FIG. 10, the power control unit 31 of the first power converter 11 includes a first filter 311, a second filter 312, and an adder 313.

The first filter 311 is a low-pass filter or a moving average filter having a fixed time constant. The autonomous control unit (30) inputs the actual power value of the second power converter 12 to the first filter 311. The first filter 311 passes only low-frequency components that do not reach a predetermined frequency in the electric power actual value of the second power converter 12 and outputs them to the adder 313.

The second filter 312 is a low-pass filter or a moving average filter having a fixed time constant. The power actual value of the fourth power converter 14 is input from the power management system to the second filter. The second filter 312 passes only the low-frequency components of the electric power actual value of the fourth power converter 14 that do not reach a predetermined frequency, and outputs the low-frequency components to the adder 313.

The adder 313 adds the low-frequency component of the actual value of the second power converter 12 and the low-frequency component of the actual value of the power of the fourth power converter 14 and outputs it to the first power converter 11 as a first power command value. . The time constant of the first filter 311 and the time constant of the second filter 312 may be the same or different.

According to the structure of FIG. 10, in addition to the effects of the above embodiment, the first power command value is composed of the low-frequency component of the actual value of the second power converter 12 and the low-frequency component of the actual value of the power of the fourth power converter 14. The sum is provided, so that, for example, the influence on the first electric power system (8a) due to the electric power fluctuation of the motor generator 90 and the sudden load fluctuation of the second electric load 7b can be suppressed. In particular, when the bus contact breaker 4 is closed without operating the second electric load 7b including a sudden change, the low-frequency component of the actual power value of the fourth power converter 14 may be set to the first Power command value.

As shown in FIG. 10, the main control unit 30 includes a first lookup table 301 and a second lookup table 302.

In the first lookup table 301, operation information (for example, a power saving instruction) indicating the position of the lever, which is input from the lever input provided on the operation table 40, is input. The first lookup table 301 memorizes the electric power command value of the motor generator 90 corresponding to the lever position of the console 40 in advance, and sets the electric power command value of the motor generator 90 corresponding to the lever position according to the input operation information and outputs it. To the power control unit 34 of the fourth power converter 14.

In the second lookup table 302, operation information (for example, a speed command) indicating the position of the lever, which is input from the lever input provided on the operation table 40, is input. The second lookup table 302 previously memorizes the revolution command value of the motor generator 90 corresponding to the lever position of the operation table 40, and sets the revolution command value of the motor generator 90 corresponding to the lever position according to the input operation information. This is output to the power control unit 34 of the fourth power converter 14.

As shown in FIG. 10, the power control unit 34 of the fourth power converter 14 includes an adder-subtractor 341, a PID control unit 342, and a switch 343.

In the adder-subtractor 341, the actual revolutions input by the revolution detection method (not shown) is subtracted from the revolution command value of the motor generator 90 input from the second lookup table 302, and the obtained result is output to the PID control unit. 342.

The PID control unit 342 generates a power command value of the motor generator 90 by performing proportional processing, integral processing, and differentiation processing on the deviation between the input revolution command value and the actual motor generator 90 revolution number, and outputs it to the switch Switch 343. In addition, integration processing or differentiation processing may be omitted.

The changeover switch 343 outputs any of the power command value of the motor generator 90 set by the first lookup table 301 and the power command value of the motor generator 90 generated by the PID control unit 342 as the fourth power command value. 4Power converter 14.

The changeover switch 343 can be operated in accordance with a changeover instruction from the main control section 30.

It is also possible to use a propulsion system that does not have a changeover switch 343 and uses only one of the motor-generator power command value and the motor-generator revolution command value.

Therefore, the fourth electric power command value is the electric power command of the motor generator 90 obtained by the rotation number control based on the deviation between the revolution number command value of the motor generator 90 and the actual revolution number of the motor generator 90 provided from the operation table 40. Value or the power command value of the motor generator 90 provided from the operation table 40. Therefore, by providing the rotation speed command value or the power command value from the operation table 40, the fourth power converter 14 can be used to perform the motor generator 90. Speed control or power control.

FIG. 11 is a block diagram showing another example of the interior of the control device 3A with probability. As shown in FIG. 11, the control device 3A includes an SOC calculation unit 411, a charge / discharge power command value calculation unit 412, a power distribution calculation unit 413, an adder 414, and an adder 415.

The AND SOC calculation unit 411 receives the current effective value or the power effective value of the third power converter 13 from the power management system. The SOC calculation unit 411 calculates the charging rate of the power storage device 2 based on the actual current value or the actual power value of the third power converter 13, and outputs it to the charge / discharge power command value calculation unit 412.

The charge / discharge power command value calculation unit 412 calculates the charge / discharge power command value based on the charge rate of the power storage device 2 and outputs it to the power distribution calculation unit 413.

Based on the charge-discharge power command value, the power distribution calculation unit 413 calculates the first charge-discharge correction power command value and the fourth charge-discharge correction power command value in order to perform charging and discharging such that the charging rate falls within a predetermined range. The first charge and discharge correction power command value is output to the adder 414, and the fourth charge and discharge correction power command value is output to the adder 415.

The adder 414 adds the first charge and discharge correction power command value and the first power command value, and outputs the obtained result to the first power converter 11. In addition, for the first power command value, the sum of the low frequency component of the actual value of the second power converter 12 and the low frequency component of the actual value of the power of the fourth power converter 14 (the output value of the adder 313 in FIG. 10) may also be used. Use the given value.

The adder 415 adds the fourth charge / discharge correction power command value and the fourth power command value, and outputs the obtained result to the fourth power converter 14. In addition, as the fourth power command value, a revolution command value from the console 40 or a value obtained based on the power command value (the output value of the switch 343 in FIG. 10) may be used, or a predetermined value may be used.

Therefore, according to the configuration of FIG. 11, by adding the first charge-discharge correction power command value and the fourth charge-discharge correction power command value based on the actual value of the third power converter 13, the power storage device 2 can be realized. SOC control.

(Third Embodiment)

Next, a third embodiment will be described. The configuration of the mobile power distribution system in this embodiment is the same as that in the first embodiment. Hereinafter, the description of the configuration common to the first embodiment will be omitted, and only the different configuration will be described.

FIG. 12 is a diagram schematically showing the configuration of a mobile body including a mobile power distribution system according to a third embodiment of the present invention. As shown in FIG. 12, the power distribution system 100B is different from the first embodiment (FIG. 1) in that it is applied to a ship equipped with a hybrid propulsion system. Specifically, the power conversion device 1A further includes a fourth power converter 14 connected to the DC intermediate section 9, and the propulsion system 200B includes a motor generator 90 connected to the AC end of the fourth power converter 14, and a transmission reduction device 60. The host 70 and the propeller 80 mounted on the propulsion shaft of the motor generator 90.

In a hybrid ship, the main engine 70 functions as a main driving source of the thruster 80, and the motor generator 90 functions as an auxiliary driving source of the thruster 80. The motor generator 90 receives power from the generator 5 connected to the bus bar 8 through the first power converter 11 and the fourth power converter 14 to generate a driving force, and supplies the driving force to the propeller 80 to assist the host. 70 pairs of thrusters 80 drive. In addition, the motor generator 90 receives power from the host 70 to generate power, and supplies the generated power to the busbar 8 through the fourth power converter 14 and the first power converter 11, thereby assisting the generator 5 to the busbar 8's power supply. Alternatively, the generator 5 may be stopped and the motor generator 90 may be used as a main power source.

In addition, although the “moving body” in the present embodiment is a ship, it is not particularly limited, and may be a vehicle (railway vehicle, automobile, etc.) or an airplane as long as it is a moving object. Moreover, although the "propeller" is a ship propeller, it is not specifically limited, As long as it is a person propelling a moving body, it may be a wheel and a flight propeller.

From the foregoing description, many improvements and other embodiments of the present invention will be apparent to the practitioner. Therefore, it should be understood that the above description is merely an example, and is provided for the purpose of guiding the industry to implement the best mode of the present invention. Substantial changes may be made to one or both of the structure and function thereof without departing from the spirit of the invention.

[Industrial availability]

The present invention is useful for an electric power system of a moving body such as a ship.

Claims (7)

    A mobile power distribution system including a first power system connected to a generator driven by a prime mover, and a first power load whose power consumption is changed by a load or regenerated from the load does not reach a predetermined value. ; The second power system, which is connected to the second power load whose variation can be changed to the above-mentioned predetermined value; the first power converter, whose AC end is connected to the first power system, and its DC end is connected to the DC intermediate part A second power converter having an AC terminal connected to the second power system and a DC terminal connected to the DC intermediate portion; a third power converter having two DC terminals connected to the DC intermediate portion and a power storage device, respectively; And a bus tie breaker, which connects the first power system and the second power system in an openable and closable manner, and forms a parallel path to a power supply path, the power supply path being from the first power system through the first 1 power converter and the second power converter reach the second power system; and the bus communication breaker is not operated when the second power load is not running It is set to the connected state, and on the other hand, it is set to the blocked state during the operation of the second electric load. The first electric power converter is based on the power efficiency value of the second electric power converter that is lower than a predetermined frequency. The first power command value given by the frequency component is controlled, the second power converter is controlled by droop, and the third power converter is controlled to eliminate the imbalance of the power flowing into or out of the DC intermediate portion.         The mobile power distribution system according to claim 1, wherein the second power converter is droop-controlled so as to be a point on a droop characteristic line, and the droop characteristic line indicates the frequency of the second power system and the second power converter. For the relationship between the actual power value of the power converter, when the second power system is blocked from the first power system, the sagging characteristic line is performed by setting the frequency of the second power system to a standard frequency. When adjusting the second power system to the first power system, adjust the power of the second power converter to 0 kW, and set the frequency of the second power system to a standard frequency. Make adjustments.         The power distribution system for a mobile body according to claim 1, further comprising a fourth power converter, the fourth power converter is connected to the DC intermediate section, an electric motor is connected to the AC end of the fourth power converter, and A propeller is mounted on a propulsion shaft of the motor.         The mobile power distribution system according to claim 1, further comprising a fourth power converter, the fourth power converter being connected to the DC intermediate section, and a motor generator connected to the AC end of the fourth power converter. The main engine and propeller are installed on the propeller shaft of the motor generator.         The mobile power distribution system according to claim 3 or 4, wherein the first electric power command value is a low frequency component that does not reach a predetermined frequency from the actual value of the second electric power converter and is converted to the fourth electric power The power efficiency value of the device is given by the sum of the low frequency components that do not reach the predetermined frequency.         The mobile power distribution system according to claim 3 or 4, wherein the fourth power converter is controlled by power based on a fourth power command value, and the fourth power command value is based on the The power command value of the motor generator obtained by the rotation number control of the deviation between the motor speed command value and the actual motor speed, or the power command value of the motor generator provided from the console.         The mobile power distribution system according to claim 3 or 4, wherein the charging rate of the power storage device is calculated based on the current effective value or the power effective value of the third power converter, so that the charging rate falls within a predetermined range. Charge and discharge in the internal manner, and calculate the first charge and discharge correction power command value and the fourth charge and discharge correction power command value, add the first charge and discharge correction power command value and the first power command value, and add the above The fourth charge / discharge correction power command value is added to the fourth power command value.