JP5553119B1 - Power supply system and power conversion device - Google Patents

Power supply system and power conversion device Download PDF

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JP5553119B1
JP5553119B1 JP2013028208A JP2013028208A JP5553119B1 JP 5553119 B1 JP5553119 B1 JP 5553119B1 JP 2013028208 A JP2013028208 A JP 2013028208A JP 2013028208 A JP2013028208 A JP 2013028208A JP 5553119 B1 JP5553119 B1 JP 5553119B1
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power
inverter
load
switch
system
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JP2014158371A (en
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克也 繁岡
竜太朗 石橋
陽一 木内
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株式会社安川電機
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Abstract

Switching between interconnection / independence is performed smoothly in a short time.
A power supply system according to an embodiment includes a power conversion device and a load. The power conversion device includes a first inverter and a second inverter. The first inverter is connected to the power system, converts the power supplied from the power generation device into power, and outputs the power to the power system. The second inverter is connected to the load, converts the power supplied from the power generation device into power, and constantly outputs the power to the load.
[Selection] Figure 1

Description

  Embodiments disclosed herein relate to a power supply system and a power conversion device.

  In recent years, in power generation systems, not only grid-connected operation but also switching to independent operation in which power is supplied to a specific load during a power failure has become important from the viewpoint of disaster prevention.

  On the other hand, it is difficult to control input energy itself such as wind power, hydraulic power, geothermal heat, etc. in a generator that generates power using natural energy such as wind power or hydraulic power, and also uses renewable energy such as exhaust heat or exhaust gas. Even in a generator that generates power, it is difficult to control input energy because the output is in accordance with the purpose of using the original energy.

  For these reasons, in a power generation system using natural energy or regenerative energy, it is difficult to stop input energy to the generator when switching between grid interconnection operation and independent operation. If switching is performed in this situation, the generator is in an unrestrained state, and if the generator speeds up and continues, a dangerous situation may occur.

  In order to solve this problem, for example, a resistor is inserted, and a current is passed through the resistor to dissipate the resistance (see Patent Document 1).

JP 2012-170305 A

  However, the above solution is not preferable because it wastes energy. In addition, since the volume is determined in proportion to the amount of heat generated, a large size resistor may be required.

  In order to reduce the above resistance, it is conceivable to stop the output by stopping the generator, but it is not easy to stop and restart the generator using wind power, hydropower, geothermal heat, etc. A generator using thermal energy such as exhaust heat or exhaust gas is not preferable because it takes time to stop and restart.

  One aspect of the embodiments has been made in view of the above, and an object of the present invention is to provide a power supply system and a power conversion device capable of smoothly switching between interconnection / independence in a short time.

  A power supply system according to an aspect of an embodiment includes a power conversion device and a load. The power conversion device includes a first inverter and a second inverter. The first inverter is connected to the power system, converts the power supplied from the power generation device into power, and outputs the power to the power system. The second inverter is connected to the load, converts the power supplied from the power generation device into power, and constantly outputs the power to the load.

FIG. 1 is a diagram illustrating an example of a configuration of a power supply system according to the embodiment. FIG. 2 is a diagram illustrating states of the first to fourth switches and the sixth switch in each mode. FIG. 3 is a diagram illustrating a transition example of the control signal and the output of the power conversion unit. FIG. 4 is a flowchart illustrating an example of processing performed by the control unit of the power conversion device.

  Hereinafter, embodiments of a power supply system and a power conversion device disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

  FIG. 1 is a diagram illustrating an example of a configuration of a power supply system according to the embodiment. A power supply system 100 illustrated in FIG. 1 includes a power conversion device 1, a power generation device 2, and a drive control unit 3, and is connected to the power system 4 and the first load 5 via terminals provided in the power conversion device 1. Connected.

  The power generation device 2 includes a generator 21 and an engine 22, and the engine 22 drives the generator 21. The drive control unit 3 is a device for driving the engine, and is connected as a load of the power conversion device 1 via a constant power supply terminal 11c described later. The power generator 2 is not limited to an engine generator.

  In the power conversion device 1 according to the present embodiment, the power generated by the power generation device 2 is constantly supplied to a first inverter 122 and a second inverter 123 described later. That is, in the power conversion device 1 according to the present embodiment, a fifth switch 15e described later is normally closed, and the converter 121 converts the power generated by the power generation device 2 into the first inverter 122 and the second inverter 123. Always supply to.

  As shown in FIG. 1, the power conversion device 1 includes a first terminal 11 a (hereinafter, referred to as “interconnection operation terminal 11 a”) and a second terminal 11 b (hereinafter, “self-sustained operation terminal 11 b”). And a third terminal 11c (hereinafter referred to as “always power supply terminal 11c”). In addition, the power conversion device 1 includes a power conversion unit 12, first to sixth switches 15a to 15f, a first voltage detection unit 16a, a second voltage detection unit 16b, an overvoltage protection circuit 17, and a control unit. 18.

  The interconnecting operation terminal 11a is a terminal for connecting to the power system 4, and has terminals for connecting the R phase, the S phase, and the neutral wire N. The interconnection operation terminal 11a outputs the electric power from the first inverter 122 included in the power conversion unit 12 to the electric power system 4 in the interconnection operation mode described later.

  The independent operation terminal 11 b is a terminal for connecting to the first load 5. The self-sustained operation terminal 11b outputs power from the first inverter 122 included in the power conversion unit 12 to the first load 5 in the below-described interconnection operation mode, and the second inverter included in the power conversion unit 12 in the self-supporting operation mode. The electric power from 123 is output to the first load 5. The first load 5 is, for example, an electric device.

  The constant power supply terminal 11c is a terminal for connecting to the second load. The constant power supply terminal 11c outputs the power from the power conversion unit 12 to the second load regardless of the operation mode (always).

  The second load is a load that constantly consumes a predetermined amount of power (hereinafter referred to as “always load”). In the present embodiment, the drive control unit 3 is always a load. The drive control unit 3 always consumes more than a predetermined amount of power to drive the engine 22 while the power generation device 2 is in operation. Note that the constant load is not limited to the drive control unit 3.

  Note that power supply to the drive control unit 3 during operation preparation (before engine startup) is performed from the power system 4 via the power conversion device 1. Specifically, the control unit 18 closes a first switch 15a, a fourth switch 15d, and a sixth switch 15f, which will be described later, and controls the first inverter 122 and the second inverter 123 to control power. The electric power from the system 4 is supplied to the drive control unit 3 from the constant power supply terminal 11 c via the first inverter 122 and the second inverter 123. In this way, the constant power supply terminal 11c always outputs the power from the power conversion unit 12 to the drive control unit 3 not only during operation of the power generation device 2 but also during preparation for operation (before engine startup).

  The interconnection operation terminal 11a, the self-sustained operation terminal 11b, and the constant power supply terminal 11c are plug-in connectors for wiring such as outlets, but can be connected to the drive control unit 3, the power system 4, or the first load 5. As long as it is, it is not limited to the plug-in connector for wiring.

  The power conversion unit 12 includes a converter 121, a first inverter 122, and a second inverter 123. The power conversion unit 12 converts AC power supplied from the power generation device 2 into predetermined power based on a control signal from the control unit 18 and outputs the predetermined power. Examples of the control signal include an operation signal and a voltage command signal for determining an output amount.

  Based on a control signal from control unit 18, converter 121 converts AC power output from power generation device 2 into DC power and outputs the DC power to a DC bus. A first inverter 122 and a second inverter 123 are connected in parallel to the DC bus. In the case where the power generator 2 is a direct current power source, the converter 121 employs a power converter that operates as a DC / DC converter.

  First inverter 122 and second inverter 123 each convert DC power output from converter 121 into AC power based on a control signal from control unit 18 and output the AC power.

  The first switch 15 a and the sixth switch 15 f are switches connected between the interconnection operation terminal 11 a and the first inverter 122. Specifically, the first switch 15a is between the connection operation terminal 11a and the sixth switch 15f, and the sixth switch 15f is between the first switch 15a and the connection operation terminal 11a. Connected. The second switch 15b is a switch having one end connected to the terminal for independent operation 11b and the other end connected to a connection line between the first switch 15a and the sixth switch 15f. The third switch 15c is a switch connected between the terminal 11b for independent operation and the second inverter 123. The fourth switch 15 d is a switch connected between the constant power supply terminal 11 c and the second inverter 123, and the fifth switch 15 e is a switch connected between the power generator 2 and the converter 121. It is a vessel.

  Opening and closing of the first to sixth switches 15 a to 15 f is controlled by the control unit 18. The first switch 15a is an example of a “connected operation switch”, and the third switch 15c is an example of a “self-operating switch”.

  The first voltage detector 16a detects the voltage between the R phase and the S phase between the sixth switch 15f and the interconnection operation terminal 11a.

  Second voltage detection unit 16 b detects a DC bus voltage between converter 121 and inverters 122 and 123, and outputs the detected value to drive control unit 3.

  The overvoltage protection circuit 17 includes a seventh switch 171 and a resistor 172, and is connected between the converter 121 and the inverters 122 and 123. The overvoltage protection circuit 17 is a circuit that prevents the overvoltage by discharging the DC power to the resistor 172 when the DC bus voltage reaches a preset value and the seventh switch 171 is closed.

  The control unit 18 controls the processing and switching of the interconnection operation mode and the independent operation mode by controlling the operation of the power conversion unit 12 and the opening and closing of the first to sixth switches 15a to 15f. FIG. 2 is a diagram illustrating states of the first switch 15a to the fourth switch 15d and the sixth switch 15f in each mode. The fourth switch 15d is normally closed, and the fifth switch 15e is closed by the control unit 18 after the operation preparation is completed and the engine 22 is started.

  The interconnection operation mode is an operation mode in which electric power generated by the power generation device 2 or electric power from the electric power system 4 is supplied to the first load 5 connected to the interconnection operation terminal 11a. In this mode, as shown in FIG. 2, the control unit 18 is a high-level control signal for closing the first switch 15a, the second switch 15b, the fourth switch 15d, and the sixth switch 15f. And a low-level control signal for opening the third switch 15c. Thereby, when the output voltage of the 1st inverter 122 is higher than the voltage of the electric power grid | system 4, the electric power grid | system 4, respectively via the connection operation terminal 11a, the independent operation terminal 11b, and the constant electric power supply terminal 11c, AC power is supplied to the first load 5 and the drive control unit 3. Further, when the output voltage of the first inverter 122 is lower than the voltage of the power system 4, the AC power from the power system 4 is connected to the interconnection operation terminal 11a, the sixth switch 15f, the second switch 15b, and the self-supporting. While being supplied to the 1st load 5 via the terminal 11b for operation, the electric power from the electric power generating apparatus 2 is always supplied to the drive control part 3 via the power supply terminal 11c. With this interconnection operation mode, use of power from the power system 4 can be suppressed, or peak cut can be realized.

  As described above, when the output voltage of the first inverter 122 is higher than the voltage of the power system 4, the power generated by the power generation device 2 is also supplied to the power system 4. As described above, the interconnection operation mode is also an operation mode in which the electric power generated by the power generation device 2 is supplied to the power system 4. In the interconnected operation mode, the voltage (DC bus voltage) output from converter 121 is set higher than in the self-sustained operation mode.

  The independent operation mode is an operation mode in which electric power generated by the power generation device 2 is supplied to the first load 5 connected to the independent operation terminal 11b via the third switch 15c. In this mode, as shown in FIG. 2, the control unit 18 outputs a low-level control signal for opening the first switch 15a, the second switch 15b, and the sixth switch 15f, and The third switch 15c is closed, and a high level control signal is output to the fourth switch 15d to hold the closed state from the interconnection operation mode. As a result, AC power is supplied to the first load 5 and the drive control unit 3 via the independent operation terminal 11b and the constant power supply terminal 11c, respectively.

  As described above, in the power conversion device 1 according to the present embodiment, the second inverter 123 is always operated, and the AC power is always output to the drive control unit 3 that is always a load regardless of the operation mode, and the operation mode. However, the AC power is always output to the first load 5 connected to the terminal for independent operation 11b.

  Switching from the interconnected operation mode to the independent operation mode is performed, for example, when a failure (for example, described as a power failure) occurs in the power system 4.

  Specifically, the control unit 18 calculates the voltage amplitude of the power system 4 from the voltage of the grid operation terminal 11a detected by the first voltage detection unit 16a, and the voltage amplitude of the power system 4 is less than a predetermined value. When it becomes, it determines with the electric power grid | system 4 having become a power failure.

  When it is determined that the power system 4 is in a power failure, the control unit 18 stops the power supply from the first inverter 122 and opens the first switch 15a, the second switch 15b, and the sixth switch 15f. Outputs the control signal to set the state. Thereby, the power supply from the first inverter 122 to the power system 4 and the first load 5 is stopped. The timing for outputting the control signal for opening the first switch 15a and the second switch 15b and the timing for outputting the control signal for opening the sixth switch 15f are the same. It does not have to be. This will be described later.

  Subsequently, the control unit 18 outputs a control signal for closing the third switch 15c, and outputs a second load voltage from the self-sustained operation terminal 11b instead of the first load voltage. As a result, power supply from the second inverter 123 to the first load 5 is started. That is, the operation mode is switched from the interconnection operation mode to the independent operation mode. The first load voltage is an output voltage when power is supplied only to the drive control unit 3, and the second load voltage supplies power to both the drive control unit 3 and the first load 5. This is the output voltage when performing.

  Thus, in the power converter device 1 according to the present embodiment, the switching from the interconnection operation mode to the independent operation mode is performed in two stages. And in the power converter device 1, after stopping the electric power supply from the 1st inverter 122 to the electric power grid | system 4 and the 1st load 5 between the 1st stage and the 2nd stage, it is the 1st load from the 2nd inverter 123. Until the power supply to 5 is started, the power generated by the power generation device 2 is constantly supplied from the constant power supply terminal 11 c to the drive control unit 3. As a result, switching between interconnection / independence can be performed smoothly in a short time.

  This point will be specifically described. Between the first stage and the second stage, in other words, until the third switch 15c is closed after the first switch 15a and the second switch 15b are opened, Described as “mode switching period”). This is because there is a case where a time lag is set in order to prevent incompatibility or the operation mode is switched manually.

  During the mode switching period, the power supply to the power system 4 and the first load 5 is stopped. In the conventional power converter, since no load is connected during the mode transition period, that is, there is no load that consumes the power generated by the power generator, power generation is performed during the mode switching period. If the device is kept operating, there is a risk that a sudden voltage rise will occur, causing damage to the converter or inverter, or the overvoltage protection circuit 17 to operate.

  On the other hand, in the power conversion device 1 according to the present embodiment, even during the mode switching period, the power output from the second inverter 123 is constantly supplied to the drive control unit 3 that is always a load. For this reason, the voltage rise during the mode switching period can be suppressed. In other words, the time until the voltage between the converter 121 and the inverters 122 and 123 exceeds the withstand voltage of the converter 121 and the inverters 122 and 123 can be extended.

  Therefore, according to the power conversion device 1 according to the present embodiment, the power conversion unit 12 is operated, that is, without stopping the power generation device 2, the transition from the grid operation mode to the independent operation mode is performed. be able to. Moreover, since it is not necessary to stop the electric power generating apparatus 2, the responsiveness at the time of power recovery can also be improved. For this reason, switching between interconnection / independence can be performed smoothly. In addition, since the mode switching period can be set short, switching between interconnection / independence can be performed in a short time. Further, the electric power generated by the power generation device 2 is always consumed by the drive control unit 3 that is a load, so that such electric power can be used without being wasted.

  Next, the above content will be specifically described with reference to FIG. FIG. 3 is a diagram illustrating a transition example of the control signal output from the control unit 18 to the first to fourth switches 15a to 15d, the detection value of the second voltage detection unit 16b, and the power generation amount of the generator 21. 3 is a control signal to the first switch 15a and the second switch 15b, S2 is a control signal to the third switch 15c, and S3 is the fourth switch 15d. Is a control signal.

  When a power failure occurs during execution of the interconnection operation mode (t1), the control unit 18 outputs a low-level control signal that opens the first switch 15a and the second switch 15b. Thereby, all the 1st-3rd switches 15a-15c will be in an open state.

  In the conventional power conversion device, if the power generation device is not stopped, when all of the first to third switches are opened as described above, no load is connected and a sudden voltage is applied. An increase occurs (see a virtual line L1 in FIG. 3). Thereby, before the self-sustained operation mode is started (t1 to t2), the voltage between the converter and the inverter may exceed these withstand voltages.

  For this reason, in a conventional power converter, for example, current is passed through a resistor and power is consumed by resistance heat radiation, a mode switching period (t1 to t2) is shortened using a high-speed cutoff switch, or the power generator itself is It stopped to prevent converter and inverter failures.

  On the other hand, according to the power converter 1 which concerns on this embodiment, even when all the 1st-3rd switches 15a-15c are in an open state, the electric power output from the 2nd inverter 123 is always a load. It is always supplied to a certain drive control unit 3. For this reason, compared with the conventional power converter device, the voltage rise in the mode switching period (t1 to t2) can be suppressed (see the virtual line L2 in FIG. 3).

  Furthermore, in the power supply system 100 according to the present embodiment, the drive control unit 3 controls the drive of the engine 22 so as to suppress the power generation amount of the generator 21 when a power failure occurs in the power system 4.

  Specifically, the drive control unit 3 determines that the power system 4 is in a state where the voltage of the interconnection operation terminal 11a detected by the first voltage detection unit 16a is less than a predetermined value for a predetermined time (Δt). Determine that a power failure occurred. The predetermined time (Δt) is set to a time shorter than the time lag of t1 to t2.

  When it is determined that the power system 4 has failed, the drive control unit 3 determines that the voltage between the converter 121 and the inverters 122 and 123 detected by the second voltage detection unit 16b is the withstand voltage Vmax of the converter 121 and the inverters 122 and 123. The driving of the engine 22 is controlled so as to be a predetermined voltage lower than that. 3 is the lowest withstand voltage of converter 121 and inverters 122 and 123. Thereby, the electric power generation amount of the generator 21 becomes P2, which is smaller than P1, and the voltage increase between t1 and t2 can be further suppressed.

  If the maximum output voltage of the power conversion unit 12 is V1, and the voltage of the drive control unit 3 that is always a load is V2, the maximum voltage V3 that can be output to the power system 4 is V1-V2, and this voltage V3 is a power failure. It is the maximum value of the excess voltage at the time. The constant load is preferably a load of voltage V2 such that voltage V3 does not exceed the withstand voltage Vmax of converter 121 and inverters 122 and 123.

  Here, the operation example of the power supply system 100 during the mode switching period when switching from the grid operation mode to the self-sustaining operation mode has been described. Similarly, it is performed in two stages.

  When switching from the self-sustained operation mode to the interconnected operation mode, the control unit 18 first outputs a control signal for opening the third switch 15c to replace the second load voltage from the self-sustained operation terminal 11b. The first load voltage is output. Thereby, the power supply from the second inverter 123 to the first load 5 is stopped while the power supply from the second inverter 123 to the drive control unit 3 is maintained. Then, the control unit 18 resumes the power supply from the first inverter 122 and outputs a control signal for closing the first switch 15a, the second switch 15b, and the sixth switch 15f. The system voltage is output from the system operation terminal 11a. Thereby, it switches from independent operation mode to interconnection operation mode.

  Even during the mode switching period from the self-sustained operation mode to the interconnected operation mode, the electric power generated by the power generator 2 is always supplied to the drive control unit 3 from the constant power supply terminal 11c. Therefore, the power conversion device 1 can smoothly switch between interconnection / independence even in a mode switching period from the independent operation mode to the interconnection operation mode.

  Note that the control unit 18 restores the power system 4 when the voltage amplitude of the power system 4 calculated from the voltage of the interconnection operation terminal 11a detected by the first voltage detection unit 16a becomes equal to or greater than a predetermined value. Determined to have been electrified. And if it determines with the electric power grid | system 4 having recovered the power, the control part 18 will output the control signal which makes an open state with respect to the 3rd switch 15c.

  In the example described above, when a power failure occurs, the first switch 15a, the second switch 15b, and the sixth switch 15f are simultaneously opened, and when the power is restored, the first switch 15a, Although the second switch 15b and the sixth switch 15f are simultaneously closed, the present invention is not limited to this.

  For example, when the control unit 18 determines that the power system 4 is in a power outage, first, in order to quickly eliminate the influence on the power system 4 side, a control signal for opening the sixth switch 15f first. Then, a control signal for opening the first switch 15a and the second switch 15b may be output. When it is determined that the power system 4 has recovered, the connection to the power system 4 is performed after the first switch 15a, the second switch 15b, and the third switch 15c have been reliably switched. Therefore, first, a control signal for opening the first switch 15a and the second switch 15b is output, and then a control signal for opening the sixth switch 15f is output. Good.

  Moreover, the control part 18 is good also as outputting the control signal which makes an open state only with respect to the 6th switch 15f, when it determines with the electric power grid | system 4 being a power failure. In such a case, when the mode switching operation is received manually, the control unit 18 outputs a control signal for opening the first switch 15a and the second switch 15b, and closes the third switch 15c. The control signal to be output may be output.

  When only the sixth switch 15f is automatically opened in the event of a power failure, the control unit 18 causes the first inverter 122 to self-run without stopping the power supply from the first inverter 122, and the first inverter Electric power may be supplied from 122 to the first load 5 via the first switch 15a, the second switch 15b, and the terminal for independent operation 11b. In such a case, the first inverter 122 may supply power at, for example, a voltage frequency set inside. Or the voltage frequency of the electric power grid | system 4 may be calculated from the voltage of the connection operation terminal 11a acquired by the 1st voltage detection part 16a before a power failure, and electric power supply may be performed with this voltage frequency.

  As described above, the power conversion device 1 according to this embodiment includes the first inverter 122 and the second inverter 123. The first inverter 122 is connected to the power system 4, converts the power supplied from the power generation device 2 into power, and outputs the power to the power system 4. The second inverter 123 is connected to the drive control unit 3 that is a load, converts the power supplied from the power generation device 2 into power, and constantly outputs the power to the drive control unit 3.

  That is, according to the power conversion device 1 according to the present embodiment, the AC power converted by the second inverter 123 is constantly output to the drive control unit 3, so that the voltage increase during the mode switching period can be suppressed. . In other words, the time until the voltage between the converter 121 and the inverters 122 and 123 exceeds the withstand voltage of the converter 121 and the inverters 122 and 123 can be extended.

  Therefore, according to the power converter device 1 which concerns on this embodiment, switching of interconnection / independence can be performed smoothly in a short time.

  Further, in the present embodiment, the drive control unit 3 suppresses the power generation amount of the generator 21 when the voltage of the interconnection operation terminal 11a becomes less than a predetermined value, that is, when a power failure occurs in the power system 4. Thus, the engine 22 is controlled. Thereby, since the electric power generation amount of the generator 21 is suppressed, the voltage rise during the mode switching period can be further suppressed.

  By the way, in the power supply system 100 which concerns on this embodiment, a load is always connected to the constant power supply terminal 11c of the power converter 1, and also the drive control part 3 controls the electric power generation amount of the generator 21, and mode switching is carried out. Although the voltage rise during the period is suppressed, even in such a case, the voltage between the converter 121 and the inverters 122 and 123 may exceed these withstand voltages during the mode switching period.

  Therefore, when the voltage of the converter 121 and the inverters 122 and 123 is likely to exceed these withstand voltages during the mode switching period, the control unit 18 controls the overvoltage protection circuit 17 (see FIG. 1) to generate excess power. May be consumed by the overvoltage protection circuit 17. An example of such a case will be described with reference to FIG. FIG. 4 is a flowchart illustrating an example of processing performed by the control unit 18 of the power conversion device 1.

  As shown in FIG. 4, the control unit 18 determines whether or not the voltage change rate between the converter 121 and the inverters 122 and 123 detected by the second voltage detection unit 16b is equal to or higher than a threshold (step S101). . For example, the threshold is set to a value higher than the voltage change rate when it is assumed that the voltage between converter 121 and inverters 122 and 123 reaches withstand voltage Vmax at the end of the mode switching period. The process of step S101 is repeatedly performed until the voltage change rate becomes equal to or greater than the threshold value.

  When the voltage change rate is equal to or higher than the threshold (Yes in step S101), that is, when the voltage may reach Vmax during the mode switching period, the control unit 18 opens the seventh open / close of the overvoltage protection circuit 17. A control signal for closing the device 171 is output (step S102).

  When the seventh switch 171 is closed, the electric power from the converter 121 is supplied to the resistor 172 and consumed by the resistor 172. Thereby, it is possible to prevent a voltage exceeding the withstand voltage of converter 121 and inverters 122 and 123 from being applied.

  As described above, the control unit 18 of the power conversion device 1 controls the seventh switch 171 to be closed when the rate of change of the voltage between the converter 121 and the inverters 122 and 123 becomes a predetermined value or more. Is output. Thereby, failure of converter 121 and inverters 122 and 123 can be prevented more reliably.

  Moreover, the control part 18 of the power converter device 1 will be in an open state with respect to the 5th switch 15e (refer FIG. 1), when the rate of change of the voltage between the converter 121 and the inverters 122 and 123 becomes more than predetermined value. A control signal may be output. In that case, it is necessary to provide a resistor between the fifth switch 15e and the engine. Also by this, failure of the converter 121 and the inverters 122 and 123 can be prevented more reliably.

  Note that here, when the “change rate” of the voltage is equal to or greater than a predetermined value, the control signal for closing the seventh switch 171 is output. However, the present invention is not limited to this. The control unit 18 may output a control signal for closing the seventh switch 171 when the voltage between the converter 121 and the inverters 122 and 123 exceeds a predetermined value.

  In the embodiment described above, an example in which the constant load connected to the constant power supply terminal 11c is the drive control unit 3 has been described, but the constant load is not limited to the drive control unit 3. For example, when the engine 22 of the power generation device 2 is a heat engine such as a Stirling engine, the constant load connected to the constant power supply terminal 11 c may be a cooling device for cooling the engine 22. Further, the constant load may be other equipment (for example, a hydraulic pump) for driving the engine. In addition, the constant power supply terminal 11c may be connected not only to the drive control unit 3 but also to other electrical devices that are always loads.

  In the above-described embodiment, an example in which the power generation device is an engine generator has been described. However, the power generation device connected to the power conversion device may be a wind power generator, a hydroelectric power generator, a geothermal power generator, or the like. It may be a power generation device. For example, when the power generation device is a hydroelectric generator, a gate or valve for adjusting the amount of water corresponds to a drive unit that drives the generator, and the drive control unit controls the gate or valve to control the amount of water. The power generation amount of the generator is controlled by adjusting. When the power generator is a wind power generator, the windmill corresponds to a drive unit that drives the power generator, and the drive control unit adjusts the rotation speed of the windmill by changing the angle of fins provided in the windmill. By controlling the power generation amount of the generator.

  As described above, in the power supply system, as a control system power supply that can be fed regardless of whether there is a power outage or equipment necessary for generator operation, for example, a fuel feed pump in a thermal system, a smoke exhaust blower, a bearing pump in a wind turbine system, etc. is there. In addition, some ventilation fans, blower fans, pumps, etc. must be operated during use and operation in facilities, buildings, and equipment. What is necessary is just to isolate | separate these from a normal general load, and to always supply electric power from the 2nd inverter 123 irrespective of the grid connection and independent operation as a constant load.

  It is also useful to connect a rechargeable battery such as a lithium ion battery in parallel with the first inverter 122 and the second inverter 123 and supply the power generated by the power generation device 2 to the rechargeable battery.

  In the above-described embodiment, the first to third switches 15a to 15c are described as switches that are closed by a high level control signal, but are switches that are closed by a low level control signal. There may be.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1 Power converter 2 Power generator (always load)
3 Drive Control Unit 4 Power System 5 First Load 11a Terminal for Interconnection Operation (First Terminal)
11b Independent operation terminal (second terminal)
11c Constant power supply terminal (third terminal)
DESCRIPTION OF SYMBOLS 12 Power conversion part 121 Converter 122 1st inverter 123 2nd inverter 15a-15f 1st-6th switch 17 Overvoltage protection circuit 171 7th switch 172 Resistor 18 Control part 100 Power supply system

Claims (6)

  1. A power converter and a load;
    The power converter is
    A first inverter connected to the power system and converting the power supplied from the power generator to output to the power system;
    A second inverter that is connected to the load, converts the power supplied from the power generation device into power and constantly outputs the power to the load ;
    A switch that switches between power from the first inverter or the power system and power from the second inverter and supplies the load to a load different from the load;
    By controlling the switch, when the power system is not out of power, supply power from the first inverter or the power system to the other load, and when the power system is out of power, And a control unit that supplies power from the second inverter to the another load .
  2. The power generator is
    A generator and a drive unit for driving the generator;
    The load is
    The power supply system according to claim 1, further comprising a drive control unit that controls the drive unit.
  3. The drive control unit
    The power supply system according to claim 2, wherein when the voltage of the power system becomes less than a predetermined value, the drive unit is controlled so as to suppress the power generation amount of the generator.
  4. The switch is
    The power conversion device including the first independent operation switch and the second independent operation switch ,
    A first terminal that is connected to the first inverter via a switch for interconnection operation, and that outputs power converted by the first inverter to the power system;
    Connected to the first inverter via the first independent operation switch, and connected to the second inverter via the second independent operation switch, by the first inverter or the second inverter. a second terminal for outputting prior Symbol another load power that is electric power conversion,
    A power supply according to any one of claims 1 to 3, further comprising: a third terminal connected to the second inverter and constantly outputting the power converted by the second inverter to the load. system.
  5. Before Symbol control unit,
    When the voltage of the power system becomes less than a predetermined value in a state where the switch for interconnection operation and the switch for first autonomous operation are closed and the switch for second autonomous operation is open, the interconnection By outputting a control signal for opening the operation switch and the first independent operation switch to the interconnection operation switch and the first independent operation switch, the power system from the first inverter The control signal for stopping the power supply to the second load from the first inverter or the power system to the other load and then closing the second autonomous switch is provided for the second autonomous operation. The power supply system according to claim 4, wherein power supply from the second inverter to the another load is started by outputting to a switch.
  6. A first inverter connected to the power system and converting the power supplied from the power generator to output to the power system;
    A second inverter that is connected to a load, converts the power supplied from the power generator, and constantly outputs the power to the load ;
    A switch that switches between power from the first inverter or the power system and power from the second inverter and supplies the load to a load different from the load;
    By controlling the switch, when the power system is not out of power, supply power from the first inverter or the power system to the other load, and when the power system is out of power, And a control unit that supplies power from the second inverter to the another load .
JP2013028208A 2013-02-15 2013-02-15 Power supply system and power conversion device Active JP5553119B1 (en)

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JP6424639B2 (en) * 2015-01-14 2018-11-21 株式会社明電舎 Stand-alone operation device of small hydropower variable speed power generation system
JP6488814B2 (en) * 2015-03-26 2019-03-27 株式会社明電舎 Operation switching device for hydroelectric power generation system

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JP2006320082A (en) * 2005-05-11 2006-11-24 Mitsubishi Electric Corp Controller of power supply system, controller of power system, control method of power supply system and control method of power system
JP2007116809A (en) * 2005-10-19 2007-05-10 Ebara Corp Wind turbine/photovoltaic hybrid power generation system

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JPS5517286A (en) * 1978-07-24 1980-02-06 Mitsubishi Electric Corp Power supply system
JPH09285016A (en) * 1996-04-11 1997-10-31 Nissin Electric Co Ltd Power equipment
JP3770532B2 (en) * 2000-06-06 2006-04-26 デンヨー株式会社 Control power compensator for engine-driven generator for grid interconnection
US8766474B2 (en) * 2011-01-12 2014-07-01 The Boeing Company Smart microgrid reconfigurable AC interface

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JP2006320082A (en) * 2005-05-11 2006-11-24 Mitsubishi Electric Corp Controller of power supply system, controller of power system, control method of power supply system and control method of power system
JP2007116809A (en) * 2005-10-19 2007-05-10 Ebara Corp Wind turbine/photovoltaic hybrid power generation system

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