JP2015046996A - Power supply system and operation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively supply power generated by a natural energy power generation device to a power system.SOLUTION: A power supply system is provided with a power storage system comprising: a power generation device for providing a direct-current output; a first power converter for orthogonal conversion; a capacitor connected in parallel to the power generation device; a boosting and step-down apparatus whose input side is parallely connected between the power generation device and the first power converter; a power storage device whose input side is connected to an output side of the boosting and step-down apparatus; and a second power converter whose one side is connected to an output side of the power storage device and whose other side is connected to an alternating-current side of the first power converter. An alternating-current side of the first power converter and an alternating-current side of the second power converter are interlinked with the power system. The power supply system comprises: means for storing power in the power storage device by operating the boosting and step-down apparatus at a voltage or lower at which the first power converter can be operated; and means for changing an output power ratio by commonly operating the first power converter and the boosting and step-down apparatus at a voltage or higher at which the first power converter can be operated and until conversion efficiency reaches a predetermined value.

Description

  The present invention relates to a power supply system including a power converter and an operation method thereof, and particularly to a power supply system that supplies power by connecting a power generator of a renewable energy such as a solar power generation system or a wind power generation system to a power system. The present invention relates to an effective power feeding system and its operation method.

  In recent years, the use of renewable energy has been promoted to improve the energy self-sufficiency rate. One of the elements is renewable energy (new energy) such as solar power generation and wind power generation. These do not worry about exhausting energy sources and do not emit CO2 during power generation, but their output is unstable because they depend on the weather. Therefore, when expanding the use of renewable energy, a power storage device is indispensable in order to suppress fluctuations in power output.

  One of the power storage devices is a power storage system. By combining the new energy and the power storage system, fluctuations in the output power of the new energy can be suppressed. When the output power of the new energy is small, the operating condition of the power conditioner PCS is not satisfied and the power conditioner PCS does not operate, so that power cannot be supplied to the power system.

  Non-Patent Document 1 introduces a technique for charging a storage battery directly via a converter that converts direct current and direct current from a solar battery to a storage battery. Further, in Patent Document 1, when the solar radiation intensity is low such as morning and evening or cloudy, the booster and the power converter are switched with the voltage at which the power conditioner PCS starts operating as a threshold, and the booster is switched below the operating voltage. A system has been introduced that stores power in a power storage system via a power converter and supplies power to a power system above a voltage at which operation starts.

Japanese Patent No. 03581699

Magazine "Electricity" March 1996 issue (published by Japan Electrical Manufacturers' Association)

  However, since power is supplied by selecting one of the booster and the power converter using the voltage at which the power converter starts operation as a threshold, the power generated by the solar cell is small and greater than the power at which the power converter operates. In such a case, there is a problem that the loss of the power converter is large and power cannot be supplied effectively.

  Further, when the capacity of the power storage system is increased, a plurality of storage batteries are used in combination, but there is a problem that the lifespan between the plurality of storage batteries cannot be made uniform, and the overall life is influenced by the storage battery having a short life.

  As described above, in the present invention, in the system in which the power generation device using natural energy, the first power converter, the buck-boost, and the power storage system are connected, the power generated by the power generation device is effectively supplied to the power system. Furthermore, it aims at enabling life management of a storage battery.

  As described above, the present invention provides a power generation device that provides a direct current output using natural energy, a first power converter that converts direct current output and alternating current of the power generation device, a power generation device, and a first power converter. A capacitor connected in parallel between the power generation device and the first power converter, a step-up / down converter connecting the input side in parallel, and a power storage device connected on the input side to the output side of the step-up / down converter Is connected to the output side of the power storage device, and the other is connected to the alternating current side of the first power converter, and the second power converter is connected to the alternating current side of the first power converter. 2 is a power feeding system in which the AC side of the power converter is connected to the power system, and when the output voltage of the power generator is equal to or lower than the voltage at which the first power converter can operate, the buck-boost is operated to store the power storage device. Means for storing power and the output voltage of the power generator is first. In a state where the power converter is at a voltage higher than the operable voltage and the conversion efficiency of the first power converter reaches a predetermined value, the operation using the first power converter and the step-up / down converter is performed. The means for changing the output power ratio is provided.

  The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

  In the power supply system of the present invention, by changing the output power ratio between the first power converter and the step-up / down converter, the power generated by the power generator can be effectively supplied to the power system and the life management can be performed. .

1 is a system block diagram illustrating an overall schematic configuration example of a power feeding system according to a first embodiment. The circuit diagram which shows the connection structural example of a 1st power converter. The circuit diagram which shows the connection structural example of a buck-boost. The figure which shows the example of transition of solar radiation intensity and the electric power which a 1st power converter outputs. The figure which shows the example of the power conversion efficiency curve of a 1st power converter. The figure which shows the output electric power ratio of the buck-boost by the conventional control, and a 1st power converter. The figure which shows the output electric power ratio of the step-up / step-down converter and the 1st power converter by this invention control. The block diagram of an example of the control content of the system control apparatus of this invention. FIG. 4 is a system block diagram illustrating an example of an overall schematic configuration of a power feeding system according to a second embodiment. The figure which shows typically the example of the storage battery capacity of the storage battery module of an initial state. The figure which shows typically the example which the capacity | capacitance of the battery module after use and deterioration reduced. The figure which shows the circuit structure at the time of storage battery module output assist. The figure which shows each part electric current change at the time of storage battery module output assist. The figure which shows the state in which the lifetime was arrange | equalized as a result of assist control. The figure which shows a circuit structure when it comprises with three storage battery modules. The figure explaining the continuous operation at the time of storage battery module disconnection. FIG. 10 is a system block diagram illustrating an example of an overall schematic configuration of a power feeding system according to a fourth embodiment. FIG. 10 is a system block diagram illustrating an overall schematic configuration example of a power feeding system according to a fifth embodiment.

  Hereinafter, in the embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments, but they are not irrelevant unless otherwise specified. Some or all of the modifications, details, supplementary explanations, and the like are related. Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 shows a power feeding system 100 as an embodiment in which the power conversion device of the present invention is applied to a system for supplying power to a power system. The power feeding system 100 is a system that is connected to the power system 110 and supplies power. The power feeding system 100 includes a power generation device 101, a capacitor 102, a first power converter 103, a buck-boost 104, a power storage system 105, and a system control device 109. In this embodiment, the case where the power system 110 is a single phase will be described as an example, but the power system 110 may be a three-phase. In this case, a three-phase power converter is used to connect to the three-phase power system 110.

  The power generation device 101 is a power generation device using natural energy such as solar power generation or wind power generation, and provides a direct current output. The power generation apparatus 101 includes a measurement device (not shown) that measures a direct current value and a direct current voltage value at an output end thereof. The output of the power generation apparatus 101 is converted into alternating current by the first power converter 103 and supplies power to the power system 110. A specific circuit configuration of the first power converter 103 is shown in FIG. 2 and will be described later.

  The power storage system 105 includes a second power converter 108 and a storage battery device 106 and is connected to the first power converter 103 in parallel. Among these, the electrical storage apparatus 106 has the storage battery module 107a and the storage battery module 107b, and these are connected in series. In FIG. 1, a storage battery is described as an example of a power storage device, but another power storage device such as a capacitor may be used. In addition, the storage battery module 107 may be formed by connecting three or more sets in series.

  The direct current side of the first power converter 103 is connected to the output end of the power generation apparatus 101, and the capacitor 102 and the input side of the buck-boost 104 are connected in parallel to this. In the example shown in the figure, the buck-boost 104 is branched and connected from the power generation device 101 side of the capacitor 102, but may be branched and connected from the first power converter 103 side of the capacitor 102. A specific circuit configuration of the buck-boost 104 is shown in FIG. 3 and will be described later.

  The power storage device 106 of the power storage system 105 is connected to the output side of the buck-boost device 104. The AC side of second power converter 108 is connected in parallel to the AC side of first power converter 103. As a result, the second power converter 108 is also linked to the power system 110.

  The control device 109 inputs current, voltage, and the like from various places in the power supply system 100 as appropriate, and appropriately supplies various operation amounts necessary for interconnection with the power system 110 (first power in the illustrated example). This is given to the converter 103 and the step-up / down converter 104) and controlled. A specific circuit configuration of the control device 109 is shown in FIG. 8 and will be described later.

  FIG. 2 shows a configuration example of the first power converter 103. The first power converter 103 includes a switching circuit 20, a DC side connection unit 21, an AC side connection unit 22, and a converter control device 27. The DC side connection unit 21 includes a measuring device 210 that measures the voltage and current on the DC side of the first power converter 103, and transmits the measured voltage data and current data to the converter control device 27. The converter control device 27 transmits the acquired data to the system control device 109 in FIG.

  The switching circuit 20 includes switching elements 23a to 26a such as an IGBT (Insulated Gate Bipolar Transistor). Note that in this embodiment, an example in which an IGBT is used as the switching elements 23a to 26a will be described. However, other switching elements such as a MOSFET (Metal Oxide Field Effect Transistor) may be used.

  The switching circuit 20 includes a first leg configured by electrically connecting an emitter of the switching element 23a of the upper arm and a collector of the switching element 24a of the lower arm, and an emitter of the switching element 25a of the upper arm. A second leg constructed by electrically connecting the collector of the lower arm switching element 26a in series; the drains of the upper arm switching elements 23a and 25a; and the lower arm switching elements 24a and 25a. Is a single-phase full-bridge inverter circuit in which the first and second legs are electrically connected in parallel. Diodes 22b to 25b are provided between the collectors and emitters of the switching elements 23a to 26a, respectively. The second power converter 108 is configured in the same manner as the first power converter 103.

  The AC side connection unit 22 includes an AC terminal connected to the power system 110. Although FIG. 2 illustrates the case of a single phase, the power system 110 may be a three-phase. In this case, the switching circuit 20 is configured as a three-phase power conversion circuit. The AC side connection unit 22 includes a measuring device 220 that measures the AC voltage and current of the power system 110, and transmits the measured voltage data and current data to the converter control device 27. The converter control device 27 transmits the acquired data to the system control device 109 in FIG.

  FIG. 3 shows a configuration example of the step-up / down regulator 104. The step-up / down device 104 includes a switching circuit 30, a direct-current side connection unit 31, an alternating-current side connection unit 32, and a step-up / step-down device control device 37.

  As shown in FIG. 1, the power storage device 106 of the power storage system 105 is connected to the AC side connection part 32 of the buck-boost 104, and the current and voltage applied to the AC side connection part 32 are DC. In this way, the AC side connection portion 32 provides a DC output, but is referred to in this way for comparison with the DC side connection portion 31.

  The switching circuit 30 in FIG. 3 includes switching elements 33 a and 34 a such as IGBTs and an inductor 35. In the present embodiment, the case where MOSFETs are used as the switching elements 33a and 34a will be described as an example. However, other switching elements such as IGBTs may be used.

  The switching circuit 30 has a configuration in which the emitter of the switching element 33a, the collector of the switching element 34a, and one end of the inductor 35 are electrically connected, and is not connected to the collector of the switching element 33a and the switching element 34a of the inductor 35. A step-up / step-down chopper circuit is formed in which the input is between the two sides and the output is between the emitter of the switching element 34a and one end of the inductor 35 on the side not connected to the switching element 34a.

  Hereinafter, taking the case where the power generation apparatus 101 is, for example, photovoltaic power generation as an example, problems in the control and operation of the power supply system 100 in FIG. 1 will be described. This problem is that sufficient generated power cannot be obtained when the solar radiation intensity, which is an energy source in solar power generation, is low, but this problem is that the generated power at the time of light wind in wind power generation cannot be obtained sufficiently. And in common. For this reason, in the following description, solar power generation is taken as an example, but this solution can be applied to wind power generation as it is.

  FIG. 4 shows a transition example of the solar radiation intensity and the power output from the first power converter 103 by the conventional control. The horizontal axis represents the time in one day from one morning to the evening. The vertical axis is biaxial, the left vertical axis indicates output power, and the right vertical axis indicates solar radiation intensity. A solid line indicates the solar radiation intensity, and a broken line indicates the output power of the first power converter 103. According to this example, output power almost proportional to the solar radiation intensity is obtained when the daytime solar radiation intensity is high, but proportional output power cannot be obtained when the morning and evening solar radiation intensity is low. There is a tendency that output power cannot be obtained unless the solar radiation intensity exceeds a certain level.

  In this figure, a period t1 indicates a period in which solar radiation intensity is present and the first power converter 103 is not operating, and a period t2 schematically indicates a period in which the power conversion efficiency of the first power converter is low. Yes. The non-operating state of the first power converter 103 is a state where the input voltage of the first power converter 103 is equal to or lower than a voltage necessary for the converter to operate (hereinafter referred to as an operable voltage). The period t2 is a period during which the power generated by the power generation apparatus cannot be effectively output because the power conversion efficiency of the first power converter 103 is low.

  FIG. 5 shows an example of the power conversion efficiency curve of the first power converter 103. The horizontal axis indicates the generated power output from the power generation apparatus 101, and the vertical axis indicates the power conversion efficiency. A period t1 indicates a period in which the first power converter 103 is not operating, and corresponds to the period t1 in FIG. A period t2 indicates a period in which the power conversion efficiency of the first power converter 103 is low, and corresponds to the period t2 in FIG. A power converter that converts direct current to alternating current, such as the first power converter 103, has a tendency that the conversion efficiency changes depending on the power to be converted, and the power conversion efficiency also decreases as the power to be converted decreases.

  FIG. 6 shows the output power ratio of the buck-boost 104 and the first power converter 103 by the conventional control. FIG. 6 shows an output ratio (vertical axis) with respect to the generated power (horizontal axis) of the power generator. FIG. 6 shows the output power ratio of the buck-boost 104 and the lower part of FIG. 6 shows the first power converter. An output power ratio of 103 is shown. In the conventional control, during the period t1 when the first power converter 103 is not operating, the buck-boost 104 is selected and operated, and the output of the power generation device 101 is stored in the storage battery 106. When the input voltage of the first power converter 103 is larger than the operable voltage and can operate, the control is performed to select and operate the first power converter 103.

  That is, the output power ratio in the period t1 is 100% for the buck-boost 104 and 0% for the first power converter 103. The output power ratio in the period t2 is 0% for the buck-boost 104 and 100% for the first power converter 103. Therefore, in the period t2 when the power conversion efficiency of the first power converter 103 is low, the power is converted only by the first power converter 103, so that power cannot be effectively supplied to the system.

  FIG. 7 shows an example of the output power ratio between the buck-boost 104 and the first power converter 103 under the control of the present invention. In this control, during the period t2 when the power conversion efficiency of the first power converter 103 is low, both the buck-boost 104 and the first power converter 103 are operated, and according to the power of the power generation device 101, the buck-boost 104 The first power conversion ratio is changed. Thereby, the electric power generated by the power generation device 101 can be effectively stored. Note that the output power ratio in the period t1 is 100% for the buck-boost 104 and 0% for the first power converter 103 as usual.

  FIG. 8 is a block diagram showing an example of the control contents of the system control apparatus 109 of the present invention. The system control device 109 in FIG. 1 inputs the voltage and current on the DC side of the first power converter 103 from the measurement device 210 provided in the converter control device 27 in FIG. Further, the voltage and current on the AC side of the first power converter 103 are input from the measuring device 220.

  In the process of FIG. 8, first, in the calculation block 401, the generated power value P101 of the power generation apparatus 101 is calculated from the voltage and current on the DC side of the first power converter 103. Next, the generated power value data of the power generator 101 calculated by the generated power calculation block 401 is input to the converter output power value calculation block 402, and the output power ratio of the first power converter 103 and the step-up / down converter 104 is calculated, The target output power value P103 of the first power converter 103 and the target output power value P104 of the buck-boost 104 are calculated.

  The specific processing here determines the output power of the first power converter 103 and the step-up / down converter 104 in accordance with the ratio characteristic of FIG. For example, in the region t1 where the generated power P103 is P4 which is equal to or less than P1, the output ratio of the step-up / down converter 104 is set to 100%, the target output power value P104 of the step-up / down converter 104 is set to P4, and the output ratio of the first power converter 103 Is set to 0%, and the target output power value P103 of the first power converter 103 is set to zero.

  In particular, in the region t2 where the generated power is P1 or more and P2 or less, when the generated power P101 of FIG. 7 is P3, the output ratio of the power converter 103 is set to 20%, for example, and the target output of the first power converter 103 The power value P103 is obtained as (0.2 * P101), the output ratio of the buck-boost 104 is set to 80%, and the target output power value P104 of the buck-boost 104 is set to (0.8 * P101). In the period t2, this ratio is sequentially changed and set according to the generated power. In this way, the converter output power value calculation block 402 stores the preset ratio characteristics as shown in FIG. 7, and the first power converter 103 and the power generator P101 according to the generated power P101 of the power generator 101. The output power ratio of the step-up / down converter 104 is calculated, and the respective target output power values P103 and P104 are given.

  In FIG. 8, a calculation block 403 calculates a voltage target value V103 output for the first power converter 103 to connect to the power system 110 using the input current and voltage on the AC system side. In this calculation, for example, it is assumed that the receiving end voltage assumed in the power system 110 is a constant value, and the voltage target value V103 as the transmitting end voltage necessary for accommodating a desired amount of power (P103) with the receiving end. Calculate In this case, the power transmission end means the AC side terminal of the first power converter 103.

  The target voltage value data V103 calculated by the target voltage calculation block 403 and the target output power value P103 of the first power converter 103 calculated by the converter output power value calculation block 402 are input to the switching pattern generation block 404a, and the first The switching pattern of the switching elements 23a to 26a of the power converter 103 is generated. The switching pattern of the first power converter 103 generated by the switching pattern generation block 404a is sent to the converter control device 27 in the first power converter 103 shown in FIG. 2 using communication means.

  Here, the switching pattern generation block 404a includes a modulator such as a PWM, and generates an ignition timing signal for the switching element of the first power converter 103 from the modulated wave and the carrier signal. At this time, a triangular wave is usually used as the carrier signal. Further, as the modulated wave, a sine waveform for a current required to obtain the target output power value P103 and the target voltage value data V103 of the first power converter 103 required at the power transmission end is calculated and used.

  Further, the target output power value P104 of the step-up / down converter 104 calculated by the converter output power value calculation block 402 is input to the switching pattern generation block 404b, and the switching patterns of the switching elements 33a, 34b of the step-up / down converter 104 are generated. The switching pattern generation block 404b also includes a modulator such as PWM, and generates an ignition timing signal for the switching element of the buck-boost 104 from the modulated wave and the carrier signal. The switching pattern of the buck-boost 104 generated here is sent to the buck-boost controller 37 in the buck-boost 104 shown in FIG. 3 using a communication means.

  As described above, the power supply system according to the present embodiment can store power in the power storage device 106 via the buck-boost 104 during the period t <b> 2 when the power conversion efficiency of the first power converter 103 is low. Therefore, the electric power generated by the power generation device 101 can be used effectively.

  In the second embodiment, a modified example of the power supply system 100 of the first embodiment will be described. In the first embodiment, by changing the output power ratio between the first power converter 103 and the step-up / down converter 104, the electric power generated by the power generation device 101 is stored in the power storage device 106 via the step-up / down step-up device 104. In the power supply system 100 according to the second embodiment, a power storage method for storing power in the power storage device 106 via the buck-boost device 104 will be described.

  FIG. 9 shows a configuration example of the power feeding system 100 according to the second embodiment. The difference from the configuration example of the power feeding system 100 of the first embodiment is that the selection device 112 is provided in the power storage system 105. The selection device 112 is installed between the buck-boost 104 and the power storage device 106, and the output side of the buck-boost 104 is selected so that the storage battery module 107a or the storage battery module 107b can be selected and connected. .

  9 is different from FIG. 1 only in the selection device portion, the following description will focus on the selection device 112 portion. The selection device 112 includes selection switches 111a and 111b, and connects the input terminals of the selection switches 111a and 111b to the output side of the buck-boost device 104. One of the two output ends of the selection switch 111a is connected to the positive electrode of the storage battery module 107a, and the other end is connected between the storage battery module 107a and the storage battery module 107b. Similarly, one of the two output terminals of the selection switch 111b is connected to the negative electrode side of the storage battery module 107b, and the other end is connected between the storage battery module 107a and the storage battery module 107b. With the configuration in FIG. 9, it is possible to individually charge the storage battery module 107 a or 107 b with the electric power generated by the power generation device 101 via the buck-boost device 104.

  FIG. 10 schematically shows an example of the storage battery capacity of the storage battery module 107 in the initial state. Here, the initial capacities of the two storage battery modules 107a and 107b are shown with the storage battery capacity on the vertical axis. In general, storage batteries have a difference in storage battery capacity due to variations in manufacturing. In the illustrated example, the initial storage battery capacity of the storage battery module 107b is lower than the initial storage battery capacity of the storage battery module 107a. On the other hand, assuming that the life capacities are the same, the storage battery capacity of the storage battery module 107b is smaller than the storage battery capacity of the storage battery module 107a, and the storage battery modules 107 having different capacities are used in parallel. In commercialization, the performance is matched as much as possible, but it is inevitable that the difference due to variation is completely matched.

  FIG. 11 schematically shows an example in which the capacity of the storage battery module is reduced due to use from the initial state of FIG. The vertical axis indicates the storage battery capacity. The example of use shown in FIG. 1 represents a state where the storage battery modules 107a and 107b are connected in series and are used evenly by the second power converter 108 as shown in FIG. As shown in FIG. 11, according to the equal usage method of the first embodiment, the storage battery module 107b having a small battery capacity in the initial state reaches the end of its service life earlier than the storage battery module 107a. As a result, the storage battery module 107a that has not yet reached the end of its life can be used as it is, but the entire life of the power storage system 105 is determined by the life of the storage battery module 107b.

  For this reason, even if the initial capacity mismatch between the storage battery modules 107a and 107b at the start of the use of the power storage system 105 is unavoidable, the end of life due to subsequent use is matched between the storage battery modules 107a and 107b. There is a demand for effective use. In the system of FIG. 9, the use of the selection device 112 can contribute to the coincidence of the end of life.

  Hereinafter, a method of using the selection device 112 that can contribute to matching the life arrival times will be described. As a precondition for this, in the case of the conventional series connection of storage battery modules in FIG. 1, a comparison is made with the case where power is supplied from the power storage device 106 to the power system 110. In this case, it is assumed that the current value It is output from the power storage device 106. At this time, each of the storage battery module 107a and the storage battery module 107b outputs a current value It / 2, and obtains a current value It as a total.

  In the embodiment of the present invention, as shown in FIG. 12, the output of the battery module 105 is assisted using the output of the buck-boost device 104. Here, the switching positions of the selection switches 111a and 111b of the selection device 112 are as shown in the figure, and the output of the step-up / down regulator 104 is connected to the storage battery module 107b. In this configuration, the storage battery module 107b and the step-up / down converter 104 are connected in parallel, and then the storage battery module 107a is connected in series.

  FIG. 13 shows each part current change when connected as shown in FIG. 12 and the storage battery module 105 assists. In the state immediately before, in order to output the current value It = 1 from the power storage device 106, it is assumed that the storage battery module 107a and the storage battery module 107b output the current value It / 2 (1/2), respectively.

  On the other hand, in the state where the storage battery module 105 assists, it is assumed that the step-up / step-down voltage generator 104 is connected in parallel to the storage battery module 107b by switching the selection switches 111a and 111b, and its output is changed over time from 0 to 0.5. Assuming that the output of the power storage system 105 is controlled to the current value It = 1, the current assisted by the buck-boost 104 is reduced from the output current of the storage battery module 107b. In this case, since the output of the storage battery module 107a is not affected by the output current of the step-up / down regulator 104, it is maintained at 0.5.

  As a result, it is possible to obtain a period of resting without using the storage battery module 107b having a small storage capacity while maintaining 1 as the overall output. Thereby, it becomes possible to delay the progress of deterioration of the storage battery module. With such assistance, the usage period of the storage battery module 107b can be reduced, and as a result, the battery module 107a can be adjusted to reach the end of its life at the same time. By assisting the low-capacity battery module 107b, the progress of deterioration can be delayed, so that the life of the battery module 107a can be aligned. FIG. 14 is a diagram showing a state in which the lifetimes are aligned as a result of the assist control.

  As described above, with the power supply system of the present embodiment, it is possible to connect the output side of the buck-boost to each storage battery module by providing the storage system with a selection device. Thereby, the output of the low-capacity storage battery module can be assisted by the output of the step-up / step-down device, and the progress of deterioration of the low-capacity storage battery module can be delayed. Therefore, the life of the power storage system can be extended.

  In addition, in FIG. 9, the example which switches the two storage battery modules 107a and 107b with the two selection switches 111a and 111b was demonstrated. When this idea is applied to, for example, three storage battery modules, the selection switch circuit may be configured as shown in FIG.

  In the second embodiment, the lifespan management of the two storage battery modules 107a and 107b is performed, and the two selection switches 111a and 111b are used by switching between them in order to equalize them. As a precondition, the two storage battery modules 107a and 107b are used. It is necessary to know the lifespan. This method of grasping the lifespan is known by performing operation history management such as SOC (state of charge) from the initial stage of manufacture, and this method is used in the operation of the present invention. The usage method can be determined with reference to the above.

  In Example 3, an operation method at the time of failure of the storage battery module will be described. In Example 2, the selection switch 111 was installed in the power storage system 105, and the power from the step-up / down regulator 104 was stored for each storage battery module 107. In the third embodiment, when the storage battery module 107 selected by the selection device 102 is disconnected by maintenance, a method for enabling the operation of the power storage system 105 by outputting the electric power output from the storage battery to be disconnected from the buck-boost device 104 will be described. .

  According to the conventional concept, for example, when the storage battery module 107a cannot supply power due to a failure, it is necessary to replace the storage battery module 107a. At this time, the power storage system 105 must stop operating.

  In the method described here, as shown in FIG. 16A, first, the timing at which the power storage system 105 does not supply power to the power system 110 via the second power converter 108 is detected. That is, it is confirmed that the second power converter 108 is stopped or disconnected from the power system 110.

  In the next stage, as shown in FIG. 16B, the two selection switches 111a and 111b are controlled to the illustrated positions. Thereby, although the storage battery module 107b is connected to the step-up / step-down device 104, the storage battery module 107a is not connected to the step-up / down step-up device 104. Further, the storage battery module 107 a is not formed with a circuit between the second power converter 108 that is stopped or disconnected from the power system 110.

  In the next stage, as shown in FIG. 16C, the voltage is output from the buck-boost unit 104 to the storage battery module 107b. The operation of the storage battery module 107b can be continued with respect to the power storage system 105 by the power output from the step-up / down converter 104.

  Finally, as shown in FIG. 16D, the failed storage battery module 107a is disconnected and a new storage battery module 107a is connected.

  As described above, even when the storage battery module of the power storage system fails and is disconnected by the power supply system of the present embodiment, it is possible to continue the operation of the power storage system by supplying power for the storage battery module in which the buck-boost device has failed. is there.

  In the fourth embodiment, a modification of the second embodiment will be described. In Example 2, the selection device was provided in the power storage system, and the output of the buck-boost was stored for each storage battery module. In the fourth embodiment, a case where a small converter is installed for each storage battery module between the second power converter and the power storage device and the storage battery module is divided will be described.

  FIG. 17 illustrates an overall schematic configuration example of the power feeding system according to the fourth embodiment. The difference in configuration from the second embodiment is that small converters 113a and 113b are installed between the power storage device 106 of the power storage system 105 and the second power converter 108, and the output of the power storage module 107a is passed through the small converter 113a. The output of the storage battery module 107b is divided so as to be output via the small converter 113b.

  In the second embodiment, the storage battery modules 107a and 107b are connected in series, and the variation of the storage battery capacity for each storage battery module is assisted by using the output of the buck-boost 104 to delay the deterioration of the low-capacity storage battery module. Life span has been extended. This measure is a non-uniform operation during the charging operation of the storage battery modules 107a and 107b.

  On the other hand, in Example 4, the non-uniform operation was performed using the small converters 113a and 113b during the discharging operation of the storage battery modules 107a and 107b. The small converters 113a and 113b can be divided and managed by controlling the storage battery modules 117a and 117b to different discharge operation states. For this reason, it becomes possible to delay the deterioration of the storage battery module having the smaller storage battery capacity, and to extend the life of the power storage system 105.

  The life equalization control on the discharge side in the fourth embodiment can obtain a higher control effect by using the life equalization control on the charging side together. By using the selection device 112 to select and store the output power of the buck-boost 104 for each of the storage battery modules 107a and 107b, the state of charge of the storage battery module can be managed.

  When the storage battery capacity of the storage battery module 107a is larger than the storage battery capacity of the storage battery module 107b, deterioration of the storage battery module 107b can be delayed by preferentially charging / discharging the storage battery module 107a via the small converter 113a.

  In order to change the charging state of the battery module 107a, when the storage battery module 107a is charged, the output of the step-up / down regulator 104 is charged to the storage battery module 107a using the selection device 112. As a result, when the charging state of the power storage module 107a is changed by charging, charging can be performed with less loss than charging through the first power converter 103, the second power converter 108, and the small converter 113a.

  As described above, when the storage battery module is divided and managed using the small converter, the charging state of the storage battery module by charging can be changed with high efficiency by the power supply system of the present embodiment. Therefore, the electric power generated by the power generator can be used effectively.

  The fifth embodiment is a modification of the fourth embodiment. Example 5 will be described with reference to FIG. In Example 4 of FIG. 17, the small converter 113a is added to the storage battery modules 107a and 107b. The method of charging the storage battery module with high efficiency in the configuration in which each of 113b is connected and power is supplied to the power system 110 via the second power converter 108 has been described. In Example 5, a method of charging a storage battery module with high efficiency in a configuration in which small converters are connected to the storage battery module and these small converters are connected in series between the first power converter and the power system. Will be described.

  FIG. 15 shows a configuration example of this embodiment. The difference from the configuration example of the fourth embodiment is that the second power converter 108 is not used, and a small battery installed to divide the storage battery modules 107a and 107b between the first power converter 103 and the power system 110. That is, the converters 113a and 113b are connected in series.

  Similarly to the fourth embodiment, when the storage battery capacity of the storage battery module 107a is larger than the storage battery capacity of the storage battery module 107b, the storage battery module 107a is preferentially charged / discharged via the small converter 113a. Deterioration can be delayed. In order to change the charging state of the storage battery module 107a, when the storage battery module 107a is charged, the output of the step-up / down regulator 104 is charged to the storage battery module 107a using the selection device 112. Thereby, when changing the charging state of the power storage module 107a by charging, charging can be performed with less loss than charging through the first power converter 108 and the small converter 113a.

  As described above, when the storage battery module is divided and managed using the small converter by the power supply system according to the fifth embodiment, the state of charge of the storage battery module can be changed with high efficiency by charging. Therefore, the electric power generated by the power generator can be used effectively.

  In addition, Example 2 to Example 5 can be performed in general operation conditions of the storage battery module 107, and can not be limitedly used only when the sunshine intensity is weak.

20: Switching circuit 21: DC side connection part 22: AC side connection parts 23a to 26a: Switching elements 22b to 25b: Diode 27: Controller 28: Smoothing capacitor 29: Switch 30: Switching circuit 31: DC side connection part 32: AC side connections 33a to 36a: switching elements 33b to 36b: parasitic diode 37: control device 100: power supply system 101: power generation device 102: capacitor 103: first power converter 104: buck-boost 105: power storage system 106 : Power storage devices 107a to 107b: storage battery module 108: second power converter 109: control device 110: power system 111a to 111b: selection switch 112: selection devices 113a to 113b: small power converter

Claims (9)

A power generation device that provides a direct current output using natural energy, a first power converter that converts direct current output and alternating current of the power generation device, and a parallel connection between the power generation device and the first power converter. One of the connected capacitor, the step-up / step-down converter that connects the input side in parallel between the power generation device and the first power converter, and the power storage device that has the input side connected to the output side of the step-up / down converter A power storage system including a second power converter connected to the output side of the power storage device and the other connected to the AC side of the first power converter; and the AC side of the first power converter; A power supply system in which the AC side of the second power converter is linked to a power system,
In a state where the output voltage of the power generator is equal to or lower than the voltage at which the first power converter can operate, means for operating the buck-boost to cause the power storage device to store power, and the output voltage of the power generator The first power converter and the step-up / step-down converter are used in combination in a state where the voltage is higher than the voltage at which the first power converter can operate and the conversion efficiency of the first power converter reaches a predetermined value. A power supply system comprising means for operating and changing the output power ratio. The power supply system according to claim 1,
When performing the operation using both the first power converter and the step-up / down converter, the first power is increased so that the ratio of the output power of the first power converter increases when the output of the power generator increases. The output power ratio of the converter and the buck-boost is changed, and the first power converter and the buck-boost so as to reduce the ratio of the output power of the first power converter when the generated power of the power generator decreases. A power supply system comprising means for changing the output power ratio of the power supply system. A power generation device that provides a direct current output using natural energy, a first power converter that converts direct current output and alternating current of the power generation device, and a parallel connection between the power generation device and the first power converter. One of the connected capacitor, the step-up / step-down converter that connects the input side in parallel between the power generation device and the first power converter, and the power storage device that has the input side connected to the output side of the step-up / down converter A power storage system including a second power converter connected to the output side of the power storage device and the other connected to the AC side of the first power converter; and the AC side of the first power converter; A power supply system in which the AC side of the second power converter is linked to a power system,
The power storage device in the power storage system is configured with a plurality of storage battery modules connected in series, a selection device is provided between the buck-boost and the power storage device, and the storage battery modules are configured to be individually selectable. A part of the plurality of connected storage battery modules is connected to the buck-boost through the selection device and supplied with power, and the second power converter is connected to both ends of the plurality of storage battery modules connected in series. Power supply system characterized by being operated. The power supply system according to any one of claims 1 to 3,
The power supply system, wherein the power storage device includes a plurality of battery modules connected in series, and the second power converter includes a plurality of small converters arranged for each of the battery modules. A power generation device that provides a direct current output using natural energy, a first power converter that converts direct current output and alternating current of the power generation device, and a parallel connection between the power generation device and the first power converter. One of the connected capacitor, the step-up / step-down converter that connects the input side in parallel between the power generation device and the first power converter, and the power storage device that has the input side connected to the output side of the step-up / down converter A power storage system including a second power converter connected to the output side of the power storage device and the other connected to the AC side of the first power converter; and the AC side of the first power converter; An operation method of a power feeding system in which the AC side of the second power converter is linked to a power system,
When the output voltage of the power generator is lower than the voltage at which the first power converter can operate, the buck-boost is operated to store power in the power storage device, and the output voltage of the power generator is the first voltage In a state where the voltage is higher than the voltage at which the power converter can operate and the conversion efficiency of the first power converter reaches a predetermined value, the first power converter and the step-up / down converter are used in combination. A method for operating the power feeding system, characterized in that the ratio of the output power is changed. An operation method of the power feeding system according to claim 5,
When performing the operation using both the first power converter and the step-up / down converter, the first power is increased so that the ratio of the output power of the first power converter increases when the output of the power generator increases. The output power ratio of the converter and the buck-boost is changed, and the first power converter and the buck-boost so as to reduce the ratio of the output power of the first power converter when the generated power of the power generator decreases. A method for operating a power feeding system comprising means for changing the output power ratio. A power generation device that provides a direct current output using natural energy, a first power converter that converts direct current output and alternating current of the power generation device, and a parallel connection between the power generation device and the first power converter. A connected capacitor, a buck-boost that connects an input side in parallel between the power generator and the first power converter, and an input side that is connected to the output side of the buck-boost via a selection device and is connected in series. A power storage device composed of a plurality of storage battery modules and a power storage device composed of a second power converter in which one is connected to the output side of the power storage device and the other is connected to the AC side of the first power converter An operation method of a power supply system including a system, wherein an alternating current side of the first power converter and an alternating current side of the second power converter are connected to a power system,
Part of the plurality of storage battery modules connected in series is connected to the buck-boost via the selection device to supply power, and the second power converter is connected to both ends of the plurality of storage battery modules connected in series. The operation method of the power feeding system is characterized in that the life of the storage battery module is adjusted by operating with the battery connected. A power generation device that provides a direct current output using natural energy, a first power converter that converts direct current output and alternating current of the power generation device, and a parallel connection between the power generation device and the first power converter. A connected capacitor, a buck-boost that connects an input side in parallel between the power generator and the first power converter, and an input side that is connected to the output side of the buck-boost via a selection device and is connected in series. A power storage device composed of a plurality of storage battery modules and a power storage device composed of a second power converter in which one is connected to the output side of the power storage device and the other is connected to the AC side of the first power converter An operation method of a power supply system including a system, wherein an alternating current side of the first power converter and an alternating current side of the second power converter are connected to a power system,
In a state where the second power converter is stopped or disconnected, and a part of the plurality of storage battery modules connected in series is connected to the buck-boost through the selection device and is supplied with power, Another part of the plurality of storage battery modules connected in series is removed. A power generation device that provides a direct current output using natural energy, a first power converter that converts direct current output and alternating current of the power generation device, and a parallel connection between the power generation device and the first power converter. A connected capacitor, a buck-boost that connects an input side in parallel between the power generator and the first power converter, and an input side that is connected to the output side of the buck-boost via a selection device and is connected in series. And a plurality of small power conversions, one of which is connected to the output side of the plurality of storage battery modules of the power storage device and the other is connected to the AC side of the first power converter. And a power storage system comprising a second power converter including a power supply, wherein the AC side of the first power converter and the AC side of the second power converter are linked to a power system. Because
The operation method of the power feeding system, wherein the life of the storage battery module is adjusted by operating some of the plurality of small power converters.

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