TWI710207B - Power supply device and control method of power supply device - Google Patents

Abstract

The power supply device (1) of the present invention includes an energy storage device (10), a converter (20) that converts a DC output into an AC output, and a control unit (60). When the output current exceeds the first limit value, the control unit (60) controls the converter (20) so that the value of the output current becomes a predetermined value greater than the first limit value by making the output voltage lower than the normal value.

Description

Power supply device and control method of power supply device

The invention relates to a power supply device and a control method of the power supply device.

Known is a power supply device including an energy storage device such as a secondary battery for backing up or smoothing the power supply from the power generation system to the power system. Such a power supply device includes a converter that converts the DC power output by the energy storage device into AC power of the required voltage and frequency. When the power supply from the power generation system drops or stops, this power supply device operates to supply the necessary AC power to the power system or specific electrical equipment. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Publication "Japanese Patent No. 6058147"

[The problem to be solved by the invention] For isolated power systems in isolated islands or between mountains, power supply devices including large-capacitor energy storage devices are also expected to be used to stabilize power supply. In such a power system, the power supply device is used for smoothing the output of a power generation system using natural energy or for backup of a power generation system requiring fuel such as a diesel generator. In this kind of application, especially when a power supply device including an energy storage device supplies power to the power system, even if a short-circuit fault occurs in the power system, it is considered that the operation of the power supply device should not be stopped. Continuous power supply.

One aspect of the present invention focuses on the subject, and aims to realize a power supply device including an energy storage device that can continuously supply power as much as possible even when a short-circuit fault occurs in the power system. [Means to solve the problem]

In order to solve the problem, a power supply device of one aspect of the present invention includes: an energy storage device; a converter, which converts the direct current (DC) output of the energy storage device into an alternating current (AC) output; A current measuring device that measures the current of the AC output; a voltage measuring device that measures the voltage of the AC output; and a control unit that controls the converter; and includes the following configuration: the control unit is configured to exceed the value of the current At the first limit value, by making the voltage lower than the normal value, the converter is controlled so that the value of the current becomes a predetermined value greater than the first limit value.

In order to solve the problem, a power supply device of another aspect of the present invention includes: an energy storage device; a converter that converts the DC output of the energy storage device into an AC output; and a current measurer that measures the current of the AC output A voltage measuring device that measures the voltage of the AC output; and a control unit that controls the converter; and includes the following structure: the control unit is provided with a current upper limit setting unit, a target voltage setting unit, and an output instruction unit, The current upper limit setting unit operates in the following manner: when the value of the current exceeds the first limit value, the current upper limit is changed from the first limit value to a second limit value greater than the first limit value, and When the value of the current falls below the first limit value, the upper limit value of the current is changed from the second limit value to the first limit value, and the output instruction unit controls the converter so that the The voltage becomes the target voltage calculated by the target voltage setting unit, and when the value of the current exceeds the first limit value, the target voltage setting unit lowers the target voltage from a normal value so that the The value of the current becomes the upper limit value of the current.

In order to solve the above-mentioned problems, a control method of a power supply device of one aspect of the present invention is a control method of a power supply device including an energy storage device and a converter that converts the DC output of the energy storage device into an AC output, including the following Configuration: when the value of the AC output current exceeds the first limit value, the converter is controlled so that the value of the current becomes greater than the first limit value by making the AC output voltage lower than the normal value The specified value of the value. [Effects of the invention]

According to one aspect of the power supply device of the present invention, it is possible to provide a power supply device including an energy storage device, which can continuously supply power as much as possible even when a short-circuit fault occurs in the power system.

According to an aspect of the control method of a power supply device of the present invention, a power supply device including an energy storage device can be realized, which can continuously supply power as much as possible even when a short-circuit fault occurs in the power system.

[Implementation Mode] Hereinafter, an embodiment of the present invention will be described in detail.

＜Constitution of power system using power supply device＞ FIG. 1 is a diagram showing a power supply device 1 according to the embodiment. FIG. 1 shows the entire power system 100 to which the power supply device 1 is applied. The power supply device 1 is a device that can store power including an energy storage device 10. The alternating current power (AC output) output by the power supply device 1 is supplied to a plurality of feeders 90.

Each feeder 90 includes a breaker 91 and a load 92. In each feeder 90, when a short-circuit fault occurs in the feeder 90, the circuit breaker 91 detects the overcurrent for a predetermined time and trips, and the feeder 90 is disconnected from the power system 100.

In addition, it is not shown in FIG. 1, but in the power system 100, a power generation system utilizing natural energy such as a solar power generation system or a wind power generation system may be arranged in parallel with the power supply device 1. Alternatively, a power generation system using fuel such as a diesel generator or a cogeneration system may be arranged in parallel with the power supply device 1. The power supply device 1 can be applied at least as a backup of the output of any one of these power generation systems. In this sense, the power supply device 1 is also an uninterruptible power supply (UPS).

As a specific example of the power system 100, an isolated power system in an isolated island or in a mountainous region can be cited. If a power generation system using natural energy is used in such a power system, by applying the power supply device 1 including the energy storage device 10, the smoothing of the power supply using natural energy can be achieved. Alternatively, if a power generation system using fuel is used in such a power system 100, the power supply device 1 may also be used as a backup power source to prevent failure of the power generation system.

However, as a specific example of the power system 100, it is not limited to an isolated power system in an island or in a mountain area, and may be a power system in a plant using a power generation system using natural energy or other power generation systems. Even the electric power system in the factory also exerts the effects and functions of the disclosure example of the present invention.

The power supply device 1 of the embodiment operates as follows: when supplying power to the power system 100, even when a short-circuit fault occurs in the feeder 90, the operation is not stopped as much as possible, and the power is continuously supplied to the power system 100. In the following description, for ease of understanding, it is described that only the power supply device 1 supplies power to the power system 100. However, if the power supply device 1 supplies power to the power system 100, the operation of the power supply device 1 is the same even if it is operated in parallel with other power generation systems.

＜Configuration of power supply device＞ As shown in FIG. 1, the power supply device 1 includes an energy storage device 10, a DC-AC converter 20 (converter), a filter 30, a current measuring device 40, a voltage measuring device 50, and a control unit 60.

The energy storage device 10 is a device that retains input power as energy, and outputs the retained energy as direct current power (DC output) as necessary. The energy storage device 10 may be a device including secondary batteries such as lithium ion batteries, NaS (sodium sulfur) batteries, redox flow batteries, and lead storage batteries.

However, the energy storage device 10 is not limited to a device including a secondary battery. As the energy storage device 10, any unit including a function of storing electric energy, such as a capacitor, a superconducting power storage unit, a flywheel type power storage unit, and a compressed air type power storage unit, can be used. In addition, the so-called energy storage device 10 is a device that outputs DC power as a concept that also includes a case where power temporarily output as AC power inside is converted into DC by a rectifier circuit, a converter, or the like. .

The DC-AC converter 20 is a device that converts the direct current power (DC output) output by the energy storage device 10 into alternating current power (AC output). The DC-AC converter 20 converts the DC power into the required voltage and frequency used by the power system 100 through the filter 30 by pulse width modulation (PWM) according to an output command from the control unit 60 AC power. The filter 30 is a filter for removing harmonics contained in the output of the DC-AC converter 20. The current measuring device 40 and the voltage measuring device 50 respectively measure the current and voltage of the alternating current power (AC output) output by the power supply device 1, and transmit the information to the control unit 60.

＜Configuration of control section＞ 2 is a block diagram showing the outline of the configuration of the control unit 60 of the power supply device 1 according to the embodiment. As shown in FIG. 2, the control unit 60 is provided with functional blocks of a current upper limit setting unit 61, a target voltage setting unit 62, and an output instruction unit 63.

First, with reference to FIG. 2, the outline of the operation of the power supply device 1 executed by the control unit 60 will be described. The output instruction unit 63, which is a region enclosed by a dotted line in FIG. 2, is a functional block normally provided by the control unit that controls the output of the DC-AC converter 20. That is, in the normal state, the output instruction unit 63 refers to the voltage measurement value detected by the voltage measurement device 50 to perform feedback control of the DC-AC converter 20 to output a target voltage that is generally a rated voltage.

However, in the control unit 60 of the present embodiment, the target voltage input to the output instruction unit 63 is generally a voltage command (normal value) of the rated voltage during normal operation, but a short-circuit fault has occurred in the feeder 90 In the case, change as follows.

The current upper limit setting unit 61 operates as follows based on the current measurement value detected by the current measuring device 40. In the normal time when the current measurement value is smaller than the first limit value, the current upper limit setting unit 61 calculates the first limit value as the current upper limit value. Here, the first limit value is set to a current value at which the DC-AC converter 20 will not be damaged even if such a current is continuously output.

When a short-circuit fault occurs in any one of the feeders 90, a fault current flows, so the current output by the DC-AC converter 20 increases sharply. Thus, the current measurement value exceeds the first limit value. When the current measurement value exceeds the first limit value, the current upper limit setting unit 61 increases the calculated current upper limit value to the second limit value.

The second limit value is a value larger than the first limit value and selected from a value below the short-time overload level of the DC-AC converter 20. In addition, the second limit value is set based on a current value that causes the circuit breaker 91 to trip due to a certain period of overcurrent in the circuit breaker 91 of the feeder 90 where a short-circuit fault has occurred. The specific value of the second limit value is suitably about 1.5 to 2 times the first limit value.

In addition, the current upper limit setting unit 61 preferably changes the current upper limit value from the first limit value to the second limit value such that the value gradually changes. The reason is that it is possible to stably perform control of the output voltage of the power supply device 1 accompanying a change in the current upper limit value.

When the current measurement value exceeds the first limit value, the target voltage setting unit 62 calculates the voltage value dropped from the voltage command (generally, the rated voltage) as the target voltage. In this way, it is fed back to the output command calculated by the output instruction unit 63 so that the current measurement value becomes the current upper limit value (a predetermined value greater than the first limit value).

As a result, when the short-circuit fault continues, the output voltage (measured voltage value) of the power supply device 1 becomes a certain voltage value lowered from the voltage command, and the output current (measured current value) becomes the second upper limit value of the current. Balance is reached at the limit value. In this way, it is controlled that these values are basically constant, and alternating current power (AC output) is output from the power supply device 1.

Then, the circuit breaker 91 of the feeder 90 in which the short-circuit fault has occurred is tripped, and the feeder 90 is disconnected. The reason is that the second limit value is set to a value such that an overcurrent (fault current) continues for a certain period of time in the circuit breaker 91 of the feeder 90 where a short-circuit fault has occurred, thereby causing a trip.

When the location where the short-circuit fault occurs is disconnected from the power system 100, the fault current no longer flows, and the current output by the DC-AC converter 20 drastically decreases and returns to a value less than the first limit value. The current upper limit setting unit 61 calculates the first limit value as the voltage upper limit value when the current measurement value falls below the first limit value. In other words, the setting of the upper limit of the voltage returns to the normal time.

Since the current measurement value does not exceed the current upper limit value, the target voltage setting unit 62 calculates the voltage command (generally, the rated voltage) as the target voltage. The output instruction unit 63 performs feedback control on the DC-AC converter 20 to output a voltage as a voltage command.

In addition, when the output voltage of the power supply device 1 returns to a normal value, it is preferable to perform control in such a manner that the output voltage is gradually changed. The reason is that when the output voltage rises sharply, a transient overcurrent (excitation inrush current) may be generated in the transformer of the power system 100, and the DC-AC converter 20 may be damaged.

<Example 1> Hereinafter, Embodiment 1 as a more specific example of the power supply device 1 and its operation will be described. FIG. 3 is a diagram showing the control logic of the control unit 60A of the power supply device 1 of the first embodiment. 4 is a timing chart showing the voltage measurement value (the output voltage of the power supply device 1), the current measurement value (the output current of the power supply device 1), and the control signal at each point of the control unit 60A in the first embodiment.

In Embodiment 1, the output command is the instantaneous value of the output voltage indicated to the DC-AC converter 20. The instantaneous value Vsin(ωt) is the product of the phase component sin(ωt) and the amplitude component V. The phase command representing the phase component sin (ωt) is calculated based on the frequency command (corresponding to ω) by the functional block of phase calculation 607.

The amplitude component V is calculated as the amplitude command S1. In addition, since the amplitude is non-negative, a limiter 606 that limits signals less than zero is provided for the calculation of the amplitude command S1. The output command is generated by multiplying the amplitude command S1 and the phase command by the multiplier 608.

The part enclosed by the broken line in FIG. 3 corresponds to the output instruction unit 63 in FIG. 2. In normal times, parts other than the part indicated by the dashed line do not affect the output command from the control unit 60. Normally, the difference (deviation S3) between the voltage command (generally the rated voltage) and the voltage measurement value is input to the voltage controller 605.

The voltage controller 605 is a functional block that performs general proportional integral (Proportional Integral, PI) control. The voltage controller 605 calculates the voltage controller output S4 based on the past integration of the deviation S3 and the deviation S3. If the integral of the deviation S3 and the deviation S3 is 0, the voltage controller 605 continues to calculate a certain value as the voltage controller output S4. If the integral of the deviation S3 and the deviation S3 is other than zero, the voltage controller 605 calculates the voltage controller output S4 so that the deviation S3 faces zero. In this way, the control unit 60A performs feedback control on the DC-AC converter 20 during the normal time (before time T1 in FIG. 4) so that the voltage measurement value becomes the voltage command (generally, the rated voltage).

The control unit 60A of the first embodiment is provided with functional blocks corresponding to the current upper limit setting unit 61 and the target voltage setting unit 62 in FIG. 2 for removing the current measuring device 40 from the current measuring device 40 when a short-circuit fault occurs in the feeder 90 The measured current value of the current is fed back to the output command.

If it is a general feedback control system that does not have these functions (only the part indicated by the dashed line in FIG. 3), when a short-circuit fault occurs in the feeder 90, the operation is as follows.

When a short-circuit fault occurs in any one of the feeders 90, the output current (measured current value) of the power supply device 1 increases sharply, and the output voltage (measured voltage value) decreases. As a result, there is a difference between the voltage command and the voltage measurement value (the deviation S3 is positive), and the voltage controller 605 intends to further increase the amplitude command.

However, there is a limit to the current that the DC-AC converter 20 can output, and its output voltage (measured voltage value) cannot be restored to the voltage command (normal value). In the power supply device 1, the voltage as commanded by the voltage controller 605 is in a state where it cannot be output. During the continuous process of the short-circuit fault, the positive state of the deviation S3 continues. Therefore, the integral of the deviation S3 of the voltage controller 605 is accumulated, and the voltage controller 605 wants to further increase the amplitude command.

In this state, when the circuit breaker 91 is tripped and the feeder is disconnected when a fault occurs, the supply of fault current disappears, and the DC-AC converter 20 can output the voltage according to the amplitude command S1 from the voltage controller 605. At this time, the amplitude command S1 is greater than the voltage command (normal value), causing a sudden increase in the output voltage.

Then, a transient overcurrent (excitation inrush current) flows through the transformer in the power system 100, and there is a possibility that the DC-AC converter 20 or the like may be damaged. In addition, at this time, even if the amplitude command is a voltage command (normal value), the output voltage will rise sharply. Therefore, in this case, the DC-AC converter 20 may be damaged.

In fact, the control unit 60A of the first embodiment operates as follows when a short-circuit fault occurs in the feeder 90.

The current upper limit L1 in FIG. 3 is the same as the current upper limit calculated by the current upper limit setting unit 61 in FIG. 2. In the normal time when the current upper limit value L1 is less than the first limit value (before time T1 in FIG. 4), the current upper limit value is the first limit value. When the current measurement value exceeds the first limit value (time T1) from the normal state, the current upper limit value L1 increases to the second limit value. The increase of the current upper limit value L1 from the first limit value to the second limit value is gradually performed (time T1 to time T2).

When the state where the current measurement value exceeds the first limit value is eliminated (time T3), after a predetermined period (time T3 to time T4) (time T4), the current upper limit value L1 returns to the first limit value. The signal waveform of the current upper limit value L1 is shown together with the graph of the current measurement value in FIG. 4.

The difference (deviation) between the current upper limit L1 and the current measurement value (when the current measurement value is an instantaneous value, it is proportional to the effective value of the current waveform calculated by the execution value calculation 601 function block) is input To the current controller 602. The current controller 602 is a functional block that performs general PI control. If the deviation and the integral of the deviation are 0, the current controller 602 continues to calculate 0 as an output. If the deviation and the integral of the deviation are other than zero, the voltage controller 605 calculates the output so that the deviation S3 faces zero.

When the output of the current controller 602 is negative by the limiter 603, it is directly calculated as the current suppression command S2. In other cases, the current suppression command S2 is 0 due to the action of the limiter, and the current measurement value is not reflected in the voltage command.

The current suppression command S2 is added to the voltage command after being multiplied by a properly set proportional coefficient K by the gain 604. The current suppression command S2 is also appropriately added to the voltage controller output S4. The sum of the current suppression command S2 and the voltage controller output S4 (which is non-negative) becomes the amplitude command S1.

At time T1 in FIG. 4, a three-phase line-to-line short-circuit fault occurs in one of the feeders 90. Here, imagine a three-phase balance failure. As a result, the current measurement value exceeds the current upper limit value (the first limit value) and increases sharply. The current controller 602 calculates a negative value to reduce the current. The current suppression command S2 is multiplied by K and added to the voltage command, and the voltage controller input S3 (deviation) becomes a large negative value. As a result, the voltage controller output S4 decreases, and the amplitude command S1 decreases from the voltage command (normal value).

As a result of the feedback control, the current measurement value becomes the current upper limit value L1, the amplitude command S1 balances and becomes constant when it becomes a certain voltage value smaller than the voltage command, and the voltage controller input S3 (deviation) is basically 0 (since time After T1 until time T3). Therefore, even if the short-circuit fault continues, the deviation will not accumulate in the voltage controller 605. Even when the short-circuit fault continues, as described above, the output voltage of the power supply device 1 is controlled to the value indicated by the control unit 60A (wherein, the value is lower than the normal value).

In addition, at this time, the deviation as the input of the current controller 602 is also zero. In particular, when the current upper limit value L1 between time T2 and time T3 becomes the second limit value, feedback control is performed on the DC-AC converter 20 so that the current measurement value becomes the second limit value. The power supply device 1 continues to output the current of the second limit value. As a result, at time T3, the circuit breaker 91 of the faulty feeder trips, and the faulty feeder disconnects. The abnormal current is removed, and the output current (measured current value) of the power supply device 1 is restored to a normal value less than the first limit value. Then, the current suppression command S2 becomes 0 and is no longer added to the voltage command.

As a result of the PI control, the voltage controller 605 gradually restores the voltage controller output S4 to the voltage command (normal value). In this way, the voltage measurement value gradually recovers from the small value during the continuation of the short-circuit fault to the voltage command (normal value) (time T3 to time T5).

<Example 2> In Embodiment 2, the short-circuit fault that occurred in one of the feeders 90 is the result of a two-phase line-to-line short-circuit fault as a three-phase unbalanced fault. The configuration of the power supply device 1 is the same as that of the first embodiment. FIG. 5 shows the waveforms of the voltage measurement value and the current measurement value in the case of Example 2. Each time T1 to time T5 shown in FIG. 5 is the same as that of the first embodiment.

As shown in the figure, even if the fault is a short-circuit fault between the two phases, the result is the same as in the case of Example 1. Immediately after the occurrence of the short-circuit fault at time T1, the output voltage of the power supply device 1 is reduced. From time T1 to time T2, the output current (measured current value) of the phase with the largest current is controlled to gradually increase from the first limit value to the second limit value.

When the state where the output current (measured current value) of the power supply device 1 is the second limit value continues, at time T3, the fault occurs and the feeder is disconnected. Then, from time T3 to time T5, the output voltage (voltage measurement value) of the power supply device 1 gradually returns to the voltage command (normal value).

<Effects> The power supply device 1 of the embodiment includes an energy storage device 10 and a DC-AC converter 20 that converts the DC output of the energy storage device 10 into AC output. Therefore, the power supply device 1 functions as a power supply for backing up or smoothing another power generation system that supplies power to the power system 100. Therefore, according to the power supply device 1, it is possible to perform power supply at night when the other power generation system is a solar power generation system, or power supply when there is no wind when the other power generation system is wind power generation. In addition, the power supply device 1 can also function as a backup against failures of other power generation systems.

In the power supply device 1 of the embodiment, when power is supplied to the power system 100, even if a short-circuit fault occurs in any one of the feeders 90, a fault current flows out and the voltage of the power system 100 drops, the power supply is suppressed from being stopped.

In a power generation system using synchronous generators, there is enough surplus power to supply more than the rated emergency current, so even in the event of a short-circuit fault, the synchronous generator is usually not disconnected from the system to stop operation. However, in a power generation system using a DC-AC converter, the capacity for supplying emergency current to the DC-AC converter is not so great. If the overcurrent continues, it will be damaged. Therefore, in the event of a short-circuit fault, it is usually Will stop operating since the system is disconnected.

However, in the power supply device 1 of the real system, even in the event of a short-circuit failure, the output voltage is controlled to a reduced state and the power is continuously supplied to the system to supply the system with a current value temporarily greater than the rated current. (The second limit value) of the current. In this way, the power supply device 1 functions as follows: it can cause the tripping of the circuit breaker 91 of the faulty feeder and disconnect the faulty feeder from the system. Therefore, although the power supply device 1 uses the power supply of the DC-AC converter 20, it can continue to supply power to the power system 100 when an abnormality such as a short-circuit fault occurs.

When the power supply device 1 is restored by the disconnection of the faulty feeder, it is controlled in a manner that the output voltage (voltage measurement value) is gradually restored. Therefore, the following situation is effectively suppressed: when the output voltage (measured voltage value) increases sharply, the transformer in the power system 100 generates a transient overcurrent (bias inrush current), which damages the DC-AC of the power supply device 1 Converter 20.

As described above, if the power supply device 1 of the embodiment is applied to the power system 100, the power supply can be continued as much as possible regardless of the occurrence of a short-circuit fault.

In the embodiment, the restoration of the current upper limit value from the second limit value to the first limit value by the current upper limit setting unit 61 is performed by detecting that the current measurement value has returned to the first limit value or less. However, the current upper limit setting unit 61 may also recover to the first limit value by receiving a signal indicating the disconnection of the feeder from the tripped circuit breaker 91.

In the embodiment, the control described as each phase is not particularly distinguished for each phase, but is performed by unified control. At this time, the control unit only needs to perform control as follows, that is, the voltage adopts the smallest value of each phase, and the current adopts the largest value of each phase as the voltage measurement value and the current measurement value. Alternatively, the three-phase instantaneous effective value (the root mean square of the instantaneous voltage value of each phase) can also be used as the current measurement value. However, the control of each phase may be performed by the control unit individually for each phase. In this case, the current upper limit may be specified uniformly or specified for each phase.

In the embodiment, the voltage command and the frequency command are regarded as fixed values, especially rated values, and are not regarded as changing values. This is equivalent to the case where the power system 100 uses a so-called Constant Voltage Constant Frequency (Constant Voltage Constant Frequency). However, when the power supply device 1 is operated in cooperation with a power generation system such as a diesel generator in which the voltage or frequency changes according to the load state, the voltage command and the frequency command can also be adjusted in response to such changes.

〔Examples of using software〕 The functional blocks of the power supply device 1 (especially the control unit 60 and the control unit 60A) can be realized by a logic circuit (hardware) formed by an integrated circuit (Integrated Circuit (IC) chip), etc. It can be realized by software.

In the latter case, the power supply device 1 includes a computer that executes commands of software that implements each function, that is, programs. The computer includes, for example, at least one processor (control device), and includes at least one storage medium readable by the computer storing the program. Moreover, in the computer, the processor reads and executes the program from the recording medium, thereby achieving the object of the invention. As the processor, for example, a central processing unit (Central Processing Unit, CPU) may be used.

As the recording medium, in addition to "non-temporary tangible media", such as read only memory (Read Only Memory, ROM), etc., tapes, discs, cards, semiconductor memories, programmable logic circuits, etc. can be used . In addition, it may further include a random access memory (Random Access Memory, RAM) for expanding the program. In addition, the program may be supplied to the computer via any transmission medium (communication network, broadcast wave, etc.) that can transmit the program. In addition, an aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave in which the program is realized by electronic transmission.

〔to sum up〕 The power supply device of aspect 1 of the present invention includes: an energy storage device; a converter that converts the DC output of the energy storage device into an AC output; a current measurer that measures the current of the AC output; a voltage measurer that measures the current The AC output voltage; and a control unit that controls the converter; and includes the following structure: when the value of the current exceeds a first limit value, the control unit makes the voltage lower than the normal value The converter is controlled so that the value of the current becomes a predetermined value greater than the first limit value.

According to the above configuration, it is possible to realize a power supply device including an energy storage device that can continue to supply power as much as possible even when a short-circuit failure or the like occurs in the power system.

According to the aspect 1, the power supply device of aspect 2 of the present invention may also be configured as follows: the control unit performs the operation such that the value of the current gradually shifts from the first limit value to the second limit value The control when the value of the current exceeds the first limit value.

According to the above configuration, in the event of a short-circuit fault, etc., the current control state can be maintained by controlling the current value to a desired value, and the AC output controlled by the power supply device can also be maintained in the case of a short-circuit fault. status.

According to the aspect 1 or the aspect 2, the power supply device of aspect 3 of the present invention may also be configured as follows: when the control unit makes the voltage lower than the normal value during the control, When the value of the current falls below the first limit value, the converter is controlled to restore the voltage to the normal value.

According to the above configuration, when a fault occurs and the feeder is disconnected, it is possible to specifically realize a configuration that restores the control state of the power supply device to the normal state.

The power supply device of aspect 4 of the present invention, according to the aspect 3, may also be configured as follows: the control unit performs the direction of the voltage so that the voltage gradually moves to the normal value Describe the restoration of normal values.

According to the above configuration, it is possible to suppress the occurrence of transient overcurrent (bias inrush current) that damages the DC-AC converter of the power supply device due to the transformer in the power system due to the rapid increase in voltage.

The power supply device of aspect 5 of the present invention includes: an energy storage device; a converter that converts the DC output of the energy storage device into an AC output; a current measurer that measures the current of the AC output; a voltage measurer that measures the current The AC output voltage; and a control unit that controls the converter; and includes the following structure: the control unit is provided with a current upper limit setting unit, a target voltage setting unit, and an output instruction unit, the current upper limit setting unit The operation is as follows: when the value of the current exceeds the first limit value, the upper limit value of the current is changed from the first limit value to a second limit value greater than the first limit value, and when the value of the current drops to no When the first limit value is reached, the current upper limit value is changed from the second limit value to the first limit value, and the output instruction unit controls the converter so that the voltage becomes the target voltage setting The target voltage is calculated by the unit, and the target voltage setting unit reduces the target voltage from a normal value when the value of the current exceeds the first limit value so that the value of the current becomes the current Upper limit.

According to the above configuration, it is possible to realize a power supply device including an energy storage device that can continue to supply power as much as possible even when a short-circuit failure or the like occurs in the power system.

The control method of the power supply device of aspect 6 of the present invention is a control method of a power supply device including an energy storage device and a converter that converts the DC output of the energy storage device into an AC output, and includes the following configuration: When the value of the output current exceeds the first limit value, the AC output voltage is lower than the normal value to control the converter so that the value of the current becomes a predetermined value greater than the first limit value.

According to the above configuration, it is possible to realize a power supply device including an energy storage device that can continue to supply power as much as possible even when a short-circuit failure or the like occurs in the power system.

The present invention is not limited to the above-mentioned embodiment, each example, etc., and various changes can be made within the scope shown in the scope of the patent application, and it is also applicable to the embodiment obtained by appropriately combining the technical components disclosed in the embodiment and the like. It is included in the technical scope of the present invention. Furthermore, by combining the disclosed technical components, new technical features can be formed.

1: Power supply unit

10: Energy storage device

20: DC-AC converter (converter)

30: filter

40: current measurer

50: Voltage measurer

60, 60A: Control Department

61: Current upper limit setting section

62: Target voltage setting section

63: output indicator

90: feeder

91: circuit breaker

92: Load

100: Power System

601: Perform value calculation

602: Current Controller

603, 606: limiter

604: gain

605: Voltage Controller

607: phase calculation

608: Multiplier

L1: current upper limit

S1: Amplitude command

S2: Current suppression command

S3: Deviation (voltage controller input)

S4: Voltage controller output

T1, T2, T3, T4, T5: time

FIG. 1 is a schematic configuration diagram showing a power supply device according to an embodiment of the present invention and a power system to which the power supply device is applied. 2 is a block diagram showing the outline of the configuration of the control unit of the power supply device according to the embodiment of the present invention. 3 is a diagram showing the control logic of the control unit of the power supply device according to Embodiment 1 of the present invention. 4 is a timing chart showing signal waveforms of various parts of the power supply device according to Embodiment 1 of the present invention. FIG. 5 is a timing chart showing signal waveforms of various parts of the power supply device according to Embodiment 2 of the present invention.

1: Power supply unit

10: Energy storage device

20: DC-AC converter (converter)

30: filter

40: current measurer

50: Voltage measurer

60: Control Department

90: feeder

91: circuit breaker

92: Load

100: Power System

Claims (5)

A power supply device, characterized by comprising: an energy storage device; a converter, which converts the direct current output of the energy storage device into an alternating current output; a current measurer, which measures the current of the alternating current output; a voltage measurer, which measures the alternating current Output voltage; and a control unit that controls the converter; and when the value of the current exceeds a first limit value, the control unit controls the converter by making the voltage lower than the normal value Make the value of the current a predetermined value greater than the first limit value, and the control unit performs the value exceeding of the current so that the value of the current gradually shifts from the first limit value to the second limit value The control at the first limit value. The power supply device according to claim 1, wherein the control unit, when the value of the current drops below the first limit during the control of making the voltage lower than the normal value In the case of the value, the converter is controlled so that the voltage returns to the normal value. The power supply device according to claim 2, wherein the control unit restores the voltage to the normal value so that the voltage gradually moves to the normal value. A power supply device, characterized by comprising: an energy storage device; A converter that converts the DC output of the energy storage device into an AC output; a current measurer that measures the current of the AC output; a voltage measurer that measures the voltage of the AC output; and a control unit that controls the converter And the control unit is provided with a current upper limit setting unit, a target voltage setting unit, and an output instruction unit, the current upper limit setting unit operates as follows: when the value of the current exceeds the first limit value, the current The upper limit value is changed from the first limit value to a second limit value greater than the first limit value, and when the value of the current drops below the first limit value, the current upper limit The value is changed from the second limit value to the first limit value, the output instruction unit controls the converter so that the voltage becomes the target voltage calculated by the target voltage setting unit, and the target voltage setting In a case where the value of the current exceeds the first limit value, the target voltage is lowered from a normal value so that the value of the current becomes the current upper limit value. A control method of a power supply device includes an energy storage device and a converter that converts the DC output of the energy storage device into an AC output. The method is characterized in that the value of the current of the AC output exceeds At the first limit value, by making the voltage of the AC output lower than the normal value, the converter is controlled so that the value of the current becomes a predetermined value greater than the first limit value, The control is performed when the value of the current exceeds the first limit value in such a manner that the value of the current gradually shifts from the first limit value to a second limit value.

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