Power supply system and power conversion device

Abstract

To provide a technology capable of continuously supplying power by suppressing interference between the output voltage control of a power generation device and the output voltage control of a power storage device during the independent operation of a distributed power supply system.SOLUTION: Disclosed is a power supply system which includes first power supply means and second power supply means and can supply AC power outputted from at least one of the first power supply means and the second power supply means to the load. The first power supply means includes: a first power supply source; a first power output terminal; and first control means. The second power supply means includes a second power supply source, a power input terminal, a second power output terminal, and second control means. When a predetermined physical quantity related to the power inputted to the power input terminal deviates from a predetermined threshold, an output power value related to the second power output terminal is maintained at a value corresponding to the load by executing a predetermined control process for the output power value related to the second power output terminal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a distributed power supply system including a plurality of power supply sources with output power control, and a power conversion device. [Background technology]

[0002] Distributed power generation systems that combine a solar or other power generation device with a storage battery have been known for some time (see, for example, Patent Documents 1 to 4). In a system that only includes a power generation device, if a commercial power grid (hereinafter simply referred to as the grid) experiences a power outage, the power generated by the power generation device cannot be fed back to the grid, and the generated power may be wasted. On the other hand, in a system that includes a storage battery such as the one described above, the generated power can be used by charging the attached storage battery so as not to be wasted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-146171 [Patent Document 2] Japanese Patent Application Publication No. 11-89096 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-55059 [Patent Document 4] Japanese Patent Application Publication No. 2019-198223 Summary of the Invention [Problem to be solved by the invention]

[0004] In the operation of the distributed power system described above, during stand-alone operation, the power generated by a power generation device such as a solar power generation device is converted into AC power via a power conditioner provided in the power generation device, and is output as drive power for driving a load, and is also input to a power conditioner of the power storage device as charging power for charging a storage battery. When the power generation device cannot generate enough power to drive the load, the operation mode of the storage device is switched from a charge mode to a discharge mode, and the stored power of the storage battery is converted into AC power via the power conditioner of the power storage device and supplied to the load.

[0005] However, when power is supplied from a power generation device to a load via a power conditioner of a power storage device during stand-alone operation, it is necessary to temporarily stop the power output to the load when switching the operation mode of the power storage device (from charge mode to discharge mode). This is because there is mutual interference between the output voltage control of the power generation device, which is the power source for driving the load, and the output voltage control of the power storage device in discharge mode. For this reason, consumers are restricted from temporarily stopping the load when switching the operation mode of the power storage device.

[0006] In addition, it is common for the rated power of the power generation device and the rated power of the power storage device to be different, which has led to the problem that the maximum power that can be supplied to the load differs when the load is driven by power supplied from the power generation device and when the load is driven by power discharged from the power storage device.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a technology that suppresses interference between the output voltage control of a first power supply device and the output voltage control of a second power supply device during autonomous operation of a distributed power supply system, thereby enabling stable power supply using the first power supply device and the second power supply device. [Means for solving the problem]

[0008] One aspect of the disclosed technology for solving the above problem is: A power supply system including a first power supply means and a second power supply means, capable of supplying AC power output from at least one of the first power supply means and the second power supply means to a load, the first power supply means includes a first power supply source, a first power output terminal that outputs AC power to the second power supply means, and first control means that controls at least an output voltage value associated with the first power output terminal; the second power supply means includes a second power supply source, a power input terminal to which the AC power output from the first power supply means is input, a second power output terminal to which the AC power is output to the load, and second control means to control at least an output power value related to the second power output terminal based on an input voltage related to the power input terminal; The second control means controls the AC power input from the power input terminal to be output from at least the second power output terminal, and when a predetermined physical quantity related to the power input to the power input terminal deviates from a predetermined threshold, performs a predetermined control process on the output power value related to the second power output terminal, thereby maintaining the output power value related to the second power output terminal at a value corresponding to the load.

[0009] Here, the first power supply means may be, for example, a solar power generation system, and the second power supply means may be, for example, a battery system including a battery, but are not limited thereto. Furthermore, the "predetermined physical quantity related to the power input to the power input terminal" may be at least one of a voltage value, a current value, and a power value measured upstream of the power input terminal, but is not limited thereto, and may be any physical quantity that can be used to determine the change in input power (voltage) at the power input terminal. For example, it may be at least one of a voltage value, a current value, and a power value measured downstream of the first power output terminal, or it may be a voltage value, a current value, or a power value measured downstream of the second power output terminal. Furthermore, the "predetermined control process" may be, for example, a process of changing a current command value related to the output power value of the second power output terminal.

[0010] With this configuration, the second control means can determine the power to be supplied to the load by controlling the output current of the second power output terminal while controlling the output voltage of the second power output terminal (i.e., the load voltage) to an extent that does not interfere with the voltage control of the first control means. More specifically, the first control means controls the output voltage of the first power output terminal, and the second control means controls the output current of the second power output terminal in accordance with the eventual voltage related to the power output from the first power output terminal and input to the power input terminal. In this way, it becomes possible to supply the output power from the first power supply means to the load via the second power supply means, and to operate the first power supply means and the second power supply means in parallel without causing interference in the control of the output voltage related to the output power to the load.

[0011] If there is a change in the output voltage of the first power output terminal that exceeds the allowable value, this is detected and the second control means controls the output power value in a feedforward (FF) manner, making it possible to provide a stable power supply to the load even when there is a sudden fluctuation in the output voltage of the first power supply means.

[0012] The second control means may further include a voltage control unit that integrates the deviation between a predetermined output voltage command value and an output voltage value related to the power output from the second power output terminal, and calculates an operation amount (or command value) related to the output current value related to the second power output terminal using the output value output from the voltage control unit, and the predetermined control process may include changing the integral value of the voltage control unit.

[0013] According to this, by using feedback (FB) control that uses the output voltage value of the second power output terminal as input information, control related to the output power from the second power output terminal is performed to a degree (low response) that does not interfere with the output voltage control by the first power supply means, and FB-like processing is performed according to the condition that the physical quantity of the target deviates from a predetermined threshold, This makes it possible to achieve highly responsive control that can quickly respond to changes in conditions.

[0014] The second control means may change the integral value of the voltage control unit to a predetermined value when a voltage value related to the power input to the power input terminal exceeds a predetermined threshold. The second control means may change the integral value of the voltage control unit using an actual output current value related to the power output from the second power output terminal when a voltage value related to the power input to the power input terminal falls below a predetermined threshold.

[0015] In this way, when the input voltage at the power input terminal (output voltage at the first power output terminal) deviates from a predetermined threshold, particularly when the input voltage drops, the output current value at the second power output terminal can be quickly controlled by manipulating the integral value in an FF manner using this as a condition, and even if the control of the output voltage at the second power output terminal is performed with a slow response that does not interfere with the output voltage control at the first power output terminal, power can be supplied to the load stably.

[0016] In addition, the second power supply means may be a power storage device having a storage battery as the second power supply source and a storage power conditioner connected to the storage battery, and may be configured to discharge power from the storage battery when a voltage value related to the power input to the power input terminal falls below a predetermined threshold.

[0017] With this configuration, the storage power conditioner can perform storage control processing related to charging and discharging based on the input voltage at the power input terminal (i.e., the output voltage output from the first power supply device). That is, when the input voltage at the power input terminal drops below a predetermined threshold, (the second control means of) the storage power conditioner can control the output current value at the second power output terminal to a value that does not stop power supply to the load by performing a discharge process from the storage battery. This also makes it possible to prevent the output voltage (load voltage) at the second current output terminal from dropping significantly below a predetermined (rated) voltage value.

[0018] The first power supply means may be a power generation device having a photovoltaic power generation module as the first power supply source and a photovoltaic power conditioner connected to the photovoltaic power generation module. Such a configuration is suitable for application of the present invention.

[0019] The present invention also provides a DC power input terminal to which DC power is input; an AC power input terminal to which AC power is input; a power conversion circuit that converts DC power and AC power; a power output terminal that outputs at least one of the AC power input from the AC power input terminal and the AC power converted by the power conversion circuit to a load; a control means for controlling at least an output power value related to the power output terminal based on an input voltage related to the AC power input terminal, The control means when a predetermined physical quantity related to the power input to the AC power input terminal deviates from a predetermined threshold, a predetermined control process is executed on an output power value related to the power output terminal, thereby maintaining the output power value related to the power output terminal at a value corresponding to the load. The present invention can also be regarded as a power conversion device characterized by the above.

[0020] The control means may further include a voltage control unit that integrates the deviation between a predetermined output voltage command value and an output voltage value related to the power output from the power output terminal, and calculates an operation amount related to the output current value related to the power output terminal using the output value output from the voltage control unit, and the predetermined control process may include changing the integral value of the voltage control unit.

[0021] Furthermore, the DC power input terminal may be connected to a storage battery as a power supply source, and the AC power input terminal may be connected to power supply means having a power supply source different from the storage battery, and the control means may perform control to discharge power from the storage battery and output it from the power output terminal when a voltage value related to the power input to the AC power input terminal falls below a predetermined threshold. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a technology that suppresses interference between the output voltage control of a power generation device and the output voltage control of a power storage device during independent operation of a distributed power system, thereby enabling a continuous power supply. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a distributed power supply system according to an application example of the present invention. [Figure 2] FIG. 2 is a block diagram showing a schematic configuration of the distributed power supply system according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram illustrating an example of a hardware configuration of a control unit of the power storage power conditioner according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a functional block diagram showing an example of a control process of the power-storage power conditioner according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a flowchart showing an example of the flow of control processing performed in the power-storage power conditioner according to the first embodiment of the present invention. [Figure 6] Fig. 6A is a block diagram showing a schematic configuration of a distributed power supply system according to embodiment 2 of the present invention. Fig. 6B is a block diagram showing a schematic configuration of a distributed power supply system according to a modified example of embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] <Application example> An application example of the present invention will be described below with reference to the drawings. The present invention can be applied to a distributed power supply system 9 as shown in Fig. 1, for example, and a power conversion device 910 used therein. Fig. 1 is a block diagram showing a schematic configuration of the distributed power supply system 9 to which the present invention is applied. As shown in Fig. 1, the distributed power supply system 9 according to this application example includes a power storage device 900 consisting of a storage battery 920 and a power conversion device 910, a load 930, and an independent power supply device 940.

[0025] A power conversion device 910 according to this application example corresponds to a so-called power conditioner that converts direct current (DC) power into alternating current (AC) power and outputs it. Hereinafter, direct current will also be referred to as DC (Direct Current), alternating current will also be referred to as AC (Alternating Current), and the power conditioner will also be referred to as PCS (Power Conditioning System). The power conversion device 910 includes a control unit 911, a storage battery connection unit 912, a load connection unit 913, a power input unit 914, a bidirectional DC / DC converter 915, a bidirectional DC / AC inverter 916, a first power circuit 917, and a second power circuit 918.

[0026] The storage battery 920 is a secondary battery such as a lithium ion battery, and is connected to the power conversion device 910 via a storage battery connector 912. Although not shown, the storage battery 920 is provided with a sensor for measuring a current value, a voltage value, a temperature, etc., and the output value of the sensor is transmitted to a control unit 911 of the power conversion device 910.

[0027] The load 930 is a general device or the like that consumes power, and is connected to the power conversion device 910 via a load connection unit 913, and receives a supply of power from the power conversion device 910. Specifically, For example, various electrical appliances used in homes, such as air conditioners, microwave ovens, and televisions, and machines and lighting equipment, such as air conditioners and lighting fixtures, used in commercial and industrial facilities.

[0028] The independent power supply device 940 is configured by a power supply source such as a renewable energy power generation device such as a solar power generation device or a wind power generation device, an engine power generation device, a fuel cell, a storage battery, etc., and a PCS that converts the power from these sources into DC / AC. The independent power supply device 940 is equipped with a power supply source (not shown), a control unit 941, and a power output unit 942, and outputs AC power from the power output unit 942 and supplies the power to the power conversion device 910 via the power input unit 914. In this way, the power input to the power conversion device 910 is supplied to the storage battery 920 and the load 930.

[0029] The power output unit 942 is configured to include terminals for outputting power to the power storage device 900, and sensors (ammeter and voltmeter) not shown. The current and voltage values ​​measured by the sensors are transmitted to the control unit 941. The control unit 941 is, for example, a microcomputer, and includes a storage medium for storing a control program and a processor for executing control procedures in accordance with the control program. The control unit 941 controls the voltage of the AC power output from the power output unit 942 based on the measurement values ​​obtained from the sensors of the power output unit 942 so that it reaches a predetermined control target value.

[0030] (Configuration of power conversion device) The control unit 911 is, for example, a microcomputer, and includes a storage medium for storing a control program and a processor for executing a control procedure in accordance with the control program. In this application example, the control unit 911 corresponds to a charging power control means, and acquires information from various sensors provided in the device as described below, and controls each component of the power conversion device 910, including the load connection unit 913, based on the information acquired by these sensors.

[0031] The battery connection unit 912 includes a terminal for inputting and outputting power to and from the battery 920. The load connection unit 913 includes a terminal for outputting power to the load 930, and sensors (ammeter and voltmeter) not shown. The current and voltage values ​​measured by the power sensors are transmitted to the control unit 911.

[0032] The power input unit 914 is configured to include a terminal for inputting power supplied from the independent power supply device 940, and sensors (a voltmeter and an ammeter) not shown. The values ​​measured by the voltmeter and the ammeter are transmitted to the control unit 911.

[0033] In addition, the bidirectional DC / DC converter 915 transforms the voltage of the DC power output from the bidirectional DC / AC inverter 916 and outputs it to the storage battery connection unit 912, and also transforms the voltage of the DC power input (discharged) from the storage battery 920 and outputs it to the bidirectional DC / AC inverter 916.

[0034] The bidirectional DC / AC inverter 916 converts the AC supplied from the independent power supply device 940 into DC and outputs it to the bidirectional DC / DC converter 915, and also converts the DC power input (discharged) from the storage battery 920 via the bidirectional DC / DC converter 915 into AC power and outputs it to the load connection unit 913.

[0035] The first power circuit 917 is a circuit for transmitting power between the storage battery connection unit 912 and the load connection unit 913 in the power conversion device 910, and is configured to include a bidirectional DC / DC converter 915 and a bidirectional DC / AC inverter 916.

[0036] The second power circuit 918 is a power supply circuit including the bidirectional DC / AC inverter 916 and the first power circuit 917. This is a circuit for transmitting power between a connection point 919 arranged between the load connection units 913 and a power input unit 914. AC power input from the power input unit 914 and transmitted through the second power circuit 918 is output from the load connection unit 913 under the control of the control unit 911 and / or converted into DC power by a bidirectional DC / AC inverter 916 and supplied as power for charging the storage battery 920.

[0037] (About power control methods) In the distributed power supply system having the above configuration, with the conventional technology, when power is supplied from the independent power supply apparatus 940 to the load 930, it is not possible to simultaneously discharge power from the storage battery 920 and supply it to the load 930. This is because the output voltage control of the control unit 941 and the output voltage control of the control unit 911 interfere with each other. For this reason, with the conventional technology, when switching to a discharge mode in which power is supplied from the storage battery 920 to the load 930, it was necessary to temporarily stop the power supply from the independent power supply apparatus 940 to the load 930, and then switch the power storage apparatus 900 to the discharge mode so that power is supplied only from the storage battery 920.

[0038] In this regard, the distributed power supply system 9 according to this application example performs the following control, thereby making it possible to supply both power output from the independent power supply apparatus 940 and the storage battery 920 to the load 930. Specifically, in the distributed power supply system 9 according to this application example, the control unit 941 controls the output voltage of the power output unit 942 to a predetermined control target value. On the other hand, when supplying power input from the power input unit 914 to the load 930, the control unit 911 controls the output voltage of the load connection unit 913 with such low response that the output power of the load connection unit 913 is determined essentially by a natural voltage based on the input voltage of the power input unit 914. Therefore, the control unit 911 controls the output current of the load connection unit 913 with high response, thereby controlling the output power of the load connection unit 913 so that the power output from the load connection unit 913 is equal to the power used by the load 930. That is, the control unit 911 controls the output voltage of the load connection unit 913 to a low response so as not to interfere with the output voltage control of the power output unit 942 of the control unit 941, and processes the output current so that the power output to the load 930 is an appropriate value. In this way, interference between the output voltage controls of the power storage device 900 and the independent power supply device 940 can be prevented, and power output from the independent power supply device 940 and the storage battery 920 can be supplied to the load 930 simultaneously.

[0039] However, if a situation occurs in which the power consumption of the load 930 exceeds the power supplied from the independent power supply apparatus 940 (for example, a sudden increase in load capacity, a decrease in the output power from the power supply source of the independent power supply apparatus 940, etc.), the output voltage of the power output unit 942 will drop suddenly. In such a case, if the output voltage control by the control unit 911 is set to a slow response as described above, it will not be able to respond to the sudden drop in output voltage, and the load and the independent power supply apparatus will stop.

[0040] For this reason, for example, when the input voltage value of the power input unit 914 deviates from (for example, falls below) a predetermined threshold value, the control unit 911 executes a predetermined control process using this as a condition, and suddenly changes the operation amount (or command value) related to the output current in a feedforward manner so as to maintain the output voltage of the load connection unit 913 at a value equal to that of the load 930.

[0041] By executing the above-described processing, even when power is being supplied to the load 930 from the independent power supply device 940, it becomes possible to supply power to the load 930 from the storage battery 920 in addition to this. In particular, in a case where the power usage of the load 930 has suddenly increased relatively to the power supplied from the independent power supply device 940, a predetermined control processing is performed, and the manipulated variable of the output current value of the load connection unit 913 is suddenly changed in an FF manner (discharge from the storage battery 920) so that the output power of the load connection unit 913 does not fall below the power usage of the load 930. In other words, the output voltage control of the power supply device and the storage battery 920 during the independent operation of the distributed power system are This can suppress interference with the output voltage control of the power device, enabling continuous power supply.

[0042] <Embodiment 1> Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0043] (System Configuration) Fig. 2 is a block diagram showing a schematic configuration of a distributed power system 1 to which the present invention is applicable. The distributed power system 1 in Fig. 2 is a hybrid power system including a power storage device 2 and a power generation device 3. As shown in Fig. 2, the distributed power system 1 constitutes a power supply system that is interconnected with a commercial power system 80 installed on the premises of a consumer, and supplies AC power to a load 50 and the interconnected power system 80. In the distributed power system 1, the power system 80 and a distribution board 82 are connected via a power line, and the load 50 is connected via the distribution board 82.

[0044] In the distributed power system 1 of FIG. 2, the power storage device 2 includes a storage battery unit 27 and a power conditioner (PCS) 20. The PCS 20 includes a control unit 21, a bidirectional DC / DC converter 22, a power conversion unit 23 (bidirectional DC / AC inverter), an independent power input unit 24, and a load connection unit 25. The bidirectional DC / DC converter 22 is connected to the storage battery unit 27 via a DC power input / output terminal (not shown). The storage battery unit 27 is a storage battery that stores a predetermined amount of power determined by a rating or the like, and the number of times it can be charged and discharged is limited by the rating or the like. In addition, each power input / output terminal including the independent power input unit 24 and the load connection unit 25 is provided with a power sensor (an ammeter and a voltmeter, not shown), which measures at least the current and voltage values ​​of the input power to the independent power input unit 24 and the current and voltage values ​​of the output power from the load connection unit 25 and transmits them to the control unit 21.

[0045] The power generation device 3 also includes a photovoltaic power generation module 37 and a power conditioner (PCS) 30. The PCS 30 includes a control unit 31, a DC / DC converter 32, a power conversion unit 33 (DC / AC inverter), and an independent power output unit 34. The DC / DC converter 32 is connected to the photovoltaic power generation module 37. The independent power output unit 34 is also provided with power sensors (ammeter, voltmeter) (not shown), which measure at least the output voltage value and send it to the control unit 31. The photovoltaic power generation module 37 is a power generation mechanism that uses sunlight as its energy source. The output (AC power) from the independent power output unit 34 of the PCS 30 is input from the independent power input unit 24 to the PCS 20 and connected to the connection point 26 via wiring within the PCS 20.

[0046] In the following, the PCS 20 of the power storage device 2 will also be referred to as the "power storage PCS 20," and the PCS 30 of the power generation device 3 will also be referred to as the "PV-PCS 30." Furthermore, in this embodiment, a solar power generation system will be described as the power generation device, but the distributed power system 1 to which the present invention is applied can employ power generation systems other than solar power generation. Examples of other power generation systems include power generation systems that use natural energy such as wind power or hydraulic power, and private power generation systems that use fuel.

[0047] In the storage PCS 20, the bidirectional DC / DC converter 22 and the power conversion unit 23 are connected by a predetermined bus (DC bus). The bidirectional DC / DC converter 22 is a unit that bidirectionally converts the voltage of the discharge power discharged from the storage battery unit 27 and the voltage of the charging power supplied from the power conversion unit 23 to the storage battery unit 27. The power conversion unit 23 is a bidirectional DC / AC inverter that includes an AC / DC converter that converts AC power supplied from the power grid 80 through the connection point 26 or AC power output from the PV-PCS 30 to the connection point 26 into DC power and outputs it to a predetermined bus, and a DC / AC inverter that converts the DC power output to the predetermined bus into AC power synchronized with the power grid 80. The net 27 and the bidirectional DC / DC converter 22 incorporate a microcomputer and the like that operates in response to control commands from the control unit 21 .

[0048] The control unit 21 is a unit including a processor (such as a CPU), a memory, a gate driver, a communication interface circuit, etc. The outputs of various sensors including power meters (current meters, voltmeters) provided at various locations are input to the control unit 21. The control unit 21 performs control processing related to charging and discharging (also referred to as power storage control processing) based on the load conditions detected through the various sensors and preset modes related to charging and discharging.

[0049] For example, when discharging, the control unit 21 performs control so that the power discharged from the storage battery unit 27 is voltage-converted via the bidirectional DC / DC converter 22, and the voltage-converted DC power is converted into AC power synchronized with the power grid 80 and output from the power conversion unit 23. When discharging is stopped, the control unit 21 stops discharging from the storage battery unit 27 and controls the power conversion unit 23 to stop outputting AC power based on the discharged power. Furthermore, when the control unit 21 determines to charge based on the above mode, load status, charge state of the storage battery unit 27, etc., it converts AC power supplied to the connection point 26 via the power grid 80 or PV-PCS 30 and controls the AC power to be charged into the storage battery unit 27. Upon receiving a control command related to the above power storage control process from the control unit 21, the operations of the storage battery unit 27, the bidirectional DC / DC converter 22, and the power conversion unit 23 are controlled.

[0050] In the PV-PCS 30, the DC / DC converter 32 and the power conversion unit 33 are connected by a predetermined bus (DC bus). The DC / DC converter 32 is a unit that converts (boosts) the voltage of DC power generated by the photovoltaic power generation module 37 and supplies the converted voltage to the predetermined bus. The power conversion unit 33 is a unit that includes a DC / AC converter that converts the DC power supplied to the predetermined bus from the DC / DC converter 32 into AC power synchronized with the power grid 80. The DC / DC converter 32 and the power conversion unit 33 incorporate a microcomputer and the like that operate in response to control commands from the control unit 31.

[0051] The control unit 31 of the PV-PCS 30 is a unit including a processor (such as a CPU), a memory, a gate driver, a communication interface circuit, etc. The outputs of various sensors, including a power sensor (not shown) provided between the photovoltaic power generation module 37 and the DC / DC converter 32, are input to the control unit 31. Based on information detected by the various sensors, the control unit 31 performs maximum power point tracking (MPPT) control so that the DC / DC converter 32 operates at the maximum power point (value of current x voltage) where the power generation output of the photovoltaic power generation module 37 is maximized or at the optimal operating point, or performs control to maintain the input voltage from the photovoltaic power generation module 37 at a certain constant value.

[0052] In the distributed power system 1, during independent operation, the power generated by the photovoltaic power generation module 37 is converted into AC power via the DC / DC converter 32 and the power conversion unit 33 of the PV-PCS 30 and input to the power storage PCS 20 (independent input). The AC power output from the power conversion unit 33 (independent output) is connected to the connection point 26 via wiring within the power storage PCS 20.

[0053] In a conventional distributed power supply system with such a configuration, when AC power input from the PV-PCS 30 is obtained in the storage PCS 30, it is necessary to switch the control process relating to the charging and discharging of the storage device 2 to the charging mode. As already explained, if both the storage PCS 20 and the PV-PCS 30 control the load voltage supplied to the load, the mutual controls interfere with each other. In the storage PCS 20 in the charging mode, current control is performed using the independent output from the PV-PCS 30 conducted to the connection point 26 as charging power, and the power conversion unit 33, the bidirectional The storage battery unit 27 is charged via the DC / DC converter 22. In the charging mode, the storage PCS 20 outputs the isolated input of the PV-PCS 30 connected to the connection point 26 as specific load power to the load in the consumer facility.

[0054] Incidentally, the power generation equipment 3 constituting the distributed power system has a rated capacity that is predefined in specifications, etc. For example, if the rated capacity of the power generation equipment 3 is 1.5 kVA, the specific load power that can be supplied to the load during stand-alone operation is limited to 1.5 kVA or less. For example, if the load capacity of the consumer is 1.8 kVA, the use of the load equipment is limited so that the rated capacity of the power generation equipment 3 does not exceed 1.5 kVA. Furthermore, even if the load is used under this limit, it is difficult to respond to temporary fluctuations in load capacity that exceed 1.5 kVA. Furthermore, the amount of power generated by the power generation equipment 3 may decrease due to weather, etc. (power generation based on natural energy such as solar, wind, hydroelectric, and geothermal). If the specifications of the storage device 2 exceed the rated capacity of the power generation device 3 (for example, 2.0 KVA), the control process for charging and discharging the storage PCS 20 can be switched to discharge mode, making it possible to supply specific load power to the consumer's load; however, since the output voltage control of the PV-PCS 30 and the output voltage control of the storage PCS 20 interfere with each other, it was necessary to temporarily stop the operation of the load.

[0055] In this regard, the distributed power supply system 1 of this embodiment is able to operate the storage PCS20 in discharge mode without interfering with the output voltage control of the PV-PCS30 and the output voltage control of the storage PCS20 by performing the following control processing.

[0056] The PV-PCS 30 of the distributed power system 1 according to this embodiment controls the output voltage of the independent power output unit 34 of the battery PCS 30 based on sensor information detected by a power sensor of the independent power output unit 34. The control unit 31 of the PV-PCS 30 performs maximum power point tracking control so that the photovoltaic power generation module 37 operates at the maximum power point (value of current x voltage) at which the power generation output of the photovoltaic power generation module 37 is maximized, or performs DC voltage control so that the DC / DC converter 32 operates at the optimum operating point. This DC voltage control refers to control that maintains the input voltage from the photovoltaic power generation module 37 at a certain constant value.

[0057] On the other hand, the power storage PCS 20 controls the specific load power supplied to the load in the consumer based on the sensor information in the independent power input unit 24 and the load connection unit 25. The control unit 21 of the power storage PCS 20 performs a power storage control process related to charging and discharging based on the load status detected through various sensors and a preset mode related to charging and discharging. This control process will be described later.

[0058] (Controller configuration) FIG. 3 is a diagram illustrating an example of the hardware configuration of the control unit 21 of the power storage PCS 20 according to this embodiment. As illustrated in FIG. 3, the control unit 21 is a computer including, as components, a processor 101, a main memory device 102, an auxiliary memory device 103, a communication IF 104, and an input / output IF 105, all of which are interconnected by a connection bus 106. The main memory device 102 and the auxiliary memory device 103 are recording media readable by the control unit 21. Each of the above components may be provided in multiple units, or some of the components may not be provided. Note that the microcomputers provided in the storage battery unit 27, the bidirectional DC / DC converter 22, the control unit 31, and the DC / DC converter 32 of the PV-PCS 30 are realized by a hardware configuration substantially equivalent to that of the control unit 21.

[0059] The processor 101 is a central processing unit that controls the entire control unit 21. The processor 101 is, for example, a CPU (Central Processing Unit), an MPU (Micro-Processing Unit), a DSP (Digital Signal Processor), etc. The processor 101 is, for example, an auxiliary storage device. The processor 101 executes a program stored in the main memory 103 in a working area of ​​the main memory 102, and controls peripheral devices through the execution of the program, thereby providing functions that meet a predetermined purpose. However, some or all of the functions provided by the processor 101 may be provided by an ASIC (Application Specific Integrated Circuit), a GPU (Graphics Processing Unit), or the like. Similarly, some or all of the functions may be realized by a dedicated LSI (large scale integration) such as an FPGA (Field-Programmable Gate Array), a numerical calculation processor, or other hardware circuit.

[0060] The main memory device 102 and the auxiliary memory device 103 constitute the memory of the control unit 21. The main memory device 102 stores programs executed by the processor 101, data processed by the processor, and the like. The main memory device 102 includes a flash memory, a random access memory (RAM), and a read-only memory (ROM). The auxiliary memory device 103 is a storage medium that stores programs executed by the processor 101 and other devices, as well as operation setting information. The auxiliary memory device 103 includes, for example, a hard-disk drive (HDD), a solid-state drive (SSD), an erasable programmable read-only memory (EPROM), a flash memory, a USB memory, and a secure digital (SD) memory card. The communication interface 104 is a communication interface with a communication network. The communication interface 104 can have an appropriate configuration depending on the connection method with the communication network. In this embodiment, various control commands are transmitted between the bidirectional DC / DC converter 22 and the storage battery unit 27 connected via the communication interface 104. Furthermore, the control unit 31 sends various control commands to and from the DC / DC converter 32 .

[0061] The input / output IF 105 is an interface for inputting and outputting data between the input device and the output device provided in the power storage PCS 21. Data is output to a display device such as an LCD or an output device such as a printer connected to the power storage PCS 21 via the input / output IF 105. Operation instructions are also accepted via the input / output IF 105, and processing intended by the operator is performed based on the operation instructions. Furthermore, in this embodiment, output signals from various sensors, including a power sensor connected via the input / output IF 105, are input to the control unit 21. The same applies to the control unit 31.

[0062] (Flow of control process for power storage PCS) Fig. 4 is a functional block diagram showing an example of control processing executed by the power storage PCS 20 according to this embodiment. The control processing shown in Fig. 4 is provided, for example, by cooperation between the control unit 21 and the power conversion unit 23 of the power storage PCS 20. In the power storage PCS 20 according to this embodiment, feedback control is performed by the control processing shown in Fig. 4 so that the output voltage (load voltage) of the load connection unit 25 becomes a control target value, and this is output as specific load power for the load in the consumer facility.

[0063] 4, the value of the independent input voltage from PV-PCS 30 input to the power storage PCS 20 (i.e., the voltage measured in power input unit 24) is input to circuit unit 43. In addition, in control unit 31 of PV-PCS 30, a control target value is set so that the output voltage value of independent power output unit 34 becomes 101 V, and output voltage is controlled. The voltage measured in power input unit 24 (independent input voltage value from PV-PCS 30) becomes a value equivalent to the voltage value output controlled by control unit 31.

[0064] In the circuit section 43, the current value input from the PV-PCS 30 (photovoltaic PCS input current) is calculated from the input stand-alone input voltage, and is output to the minor control section 42. In addition, in the circuit section 43, a current value corresponding to the voltage input from the minor control section 42 to the circuit section 43 is calculated, and is output again to the minor control section 42. In addition, The output voltage (that is, the output voltage at the load connection section 25 ) is input to the calculator 45 .

[0065] Furthermore, the independent input voltage value from the PV-PCS 30 input to the power storage PCS 20 is input to the integral value processing determination unit 44 and used for feedforward control, which will be described later.

[0066] 4 calculates a differential voltage (deviation) between the output voltage command value and the output voltage, and the differential voltage is input to the output voltage control unit 41. The output voltage command value is generated by the control unit of the power storage PCS 20.

[0067] In the output voltage control unit 41, the differential voltage (deviation) calculated by the calculator 45 is integrated, and the integrated value is used to generate a current reference value for minor loop control in which the output voltage value of the power storage PCS 20 is set as a control target value. The current reference value generated in the output voltage control unit 41 is further input to the calculator 46, where it is added with a charging current command value separately generated by the control unit 21, and input to the minor control unit 42.

[0068] As described above, the output voltage value of the independent power output unit 34 is controlled to a predetermined voltage (for example, 101 V), and therefore the storage battery unit 27 cannot be charged as is when there is no load or a light load. For this reason, when charging the storage battery unit 27, a separate current value for charging is commanded in a feedforward manner.

[0069] The minor control unit 42 performs value tracking control with the current values ​​of the output current and the solar PCS input current fed back from the circuit unit 43 as control variables and the output voltage as a manipulated variable, with the current value input from the calculator 46 as a target value. The minor control unit 42 performs current control based on the current values ​​of the output current and the solar PCS input current fed back from the circuit unit 43, and controls the output voltage to be constant.

[0070] Incidentally, the power output from the independent power output unit 34 of the PV-PCS 30 is input from the power input unit 24 and output from the load connection unit 25 via the connection point 26. In other words, if the output voltage control process shown in FIG. 4 is highly responsive, interference will occur with the output voltage control by the control unit 31 of the PV-PCS 30. For this reason, the output voltage control by the power storage PCS 20 is kept to a low response so as not to interfere with the output voltage control of the PV-PCS 30. For this reason, the output voltage control of the power storage PCS according to this embodiment is actually performed based on the independent input voltage value controlled by the control unit 31 of the PV-PCS 30 (at a natural voltage value).

[0071] (Feedforward control during sudden load changes) In the distributed power system 1 according to this embodiment, interference between the output voltage control of the PV-PCS 30 and the output voltage control of the power storage PCS 20 can be prevented. However, as described above, the control of the output voltage from the power storage PCS 20 has a slow response, and therefore there is a risk that it will not be able to respond appropriately to a sudden change in the balance between the load capacity and the generated power due to a temporary sudden increase in load, a change in weather, or other reasons. Specifically, if the load capacity of the consumer exceeds the generated power of the power generation device 3, the output voltage of the independent power output unit 34 drops rapidly. If the output voltage of the load connection unit 25 is controlled based on this voltage, the output voltage control of the power storage PCS 20 (control to immediately increase the output voltage value) will not be able to keep up, and the load 50 will stop.

[0072] Therefore, the control unit 21 of the power storage PCS 20 according to this embodiment controls the output voltage of the load connection unit 25 in the following manner, and operates the output voltage control unit 41 in a feedforward manner when the load suddenly changes, to maintain the output voltage of the load connection unit 25 within a predetermined range. FIG. 5 is a flowchart showing an example of the process performed by the control unit 21. As shown in FIG. 5, the control unit 21 first acquires the input voltage value in the power input unit 24 (S101). Next, The unit 21 acquires the output current value (load current value) at the load connection unit 25 (S102). Then, the output voltage value acquired in step S101 is input to the integral value processing determination unit 44 in Fig. 4, and the integral value processing determination unit 44 determines whether or not the output voltage value is below a predetermined lower limit threshold (S103).

[0073] If it is determined in step S103 that the output voltage is below the predetermined lower threshold, the process proceeds to step S104, where a process is executed to manipulate the integral of the deviation between the output voltage command value and the output voltage, which is integrated in output voltage control unit 41. In step S104, the integral of output voltage control unit 41 is rewritten using the load current value acquired in step S102, so that the output voltage value from load connection unit 25 can be maintained within a predetermined range. This allows the current reference value output from output voltage control unit 41 to be changed immediately and suddenly. After the process of step S104, the process proceeds to step S107.

[0074] When the integral value of the output voltage control unit 41 is rewritten in step S104, the power storage PCS 20 supplies power to the load 50 by quickly discharging power from the storage battery unit 27. This has the same meaning as a (relative) decrease in load capacity from the viewpoint of the power generation device 3, and essentially eliminates the state in which the load capacity exceeds the power generation power of the power generation device 3, thereby preventing the output voltage from decreasing significantly from the predetermined control target value.

[0075] If it is determined in step S103 that the output voltage value is not below the predetermined lower threshold, the process proceeds to step S105, where the integral value processing determination unit 44 determines whether the output voltage value acquired in step S101 exceeds a predetermined upper threshold (S105). If it is determined that the output voltage value does not exceed the predetermined upper threshold, the process proceeds to step S107.

[0076] On the other hand, if it is determined in step S105 that the predetermined upper threshold is exceeded, the process proceeds to step S106, where a process is executed to manipulate the integral value of the deviation between the output voltage command value and the output voltage, which is integrated in output voltage control unit 41. In step S106, the integral value of output voltage control unit 41 is rewritten using a predetermined reset value that is set in advance, so that the output voltage value from load connection unit 25 can be maintained within a predetermined range. This allows the current reference value output from output voltage control unit 41 to be changed immediately and suddenly. After the process of step S106, the process proceeds to step S107.

[0077] In step S107, it is determined whether a predetermined termination condition (for example, the arrival of a predetermined period of time or the reception of a stop signal) is met, and if it is determined that the condition is met, the flow ends. On the other hand, if it is determined in step S107 that the predetermined termination condition is not met, the flow returns to step S101 and the series of processes are repeated.

[0078] As described above, the power storage PCS 20 according to this embodiment executes a process for controlling the output voltage value of the load connection unit 25 in a feedforward manner when the input voltage of the power input unit 24 deviates from a predetermined upper or lower threshold. This allows for low-response output voltage control of the load connection unit 25, suppressing interference with the output voltage control of the PV-PCS 30, and preventing the load 50 from shutting down even when the load capacity exceeds the power generated by the power generation device 3. That is, the distributed power system 1 according to this embodiment suppresses interference between the output voltage control of the power generation device and the output voltage control of the power storage device during autonomous operation of the distributed power system, enabling continuous power supply and providing the load 50 with power up to the combined rated capacity of the power storage device 2 and the power generation device 3. In the above embodiment, the power storage PCS 20 corresponds to the power conversion device according to the present invention.

[0079] (Variation) In the above embodiment, the power supply source that outputs power to the power storage device 2 is a solar power generation device serving as the power generation device 3. However, this is not limited to this. For example, the power supply source may be a power generation device that uses renewable energy other than solar power, such as wind power, as a power supply source, or an engine generator (fueled by gas, gasoline, diesel, or the like) that is not affected by weather. In such cases, for example, the rated capacity (power upper limit) of the power supply source or a value obtained by subtracting a predetermined value from this may be set as a predetermined upper limit threshold. When the load capacity exceeds the upper limit threshold, a rewrite process for the integrated value of the output voltage control unit 41 may be performed. Whether the load capacity has exceeded the predetermined upper limit threshold can be determined based on the power value (voltage value, current value) measured by the power input unit 24 or the load connection unit 25.

[0080] <Embodiment 2> In the above embodiment, the power supply source that outputs power to the power storage device 2 is the power generation device 3, but the power supply source is not necessarily limited to a power generation device. For example, other power storage devices (storage battery units and power storage PCSs) or an uninterruptible power supply (UPS) can also be used as the power supply source. FIG. 6A shows a schematic diagram of a distributed power system according to such another embodiment. The distributed power system 10 shown in FIG. 6A is configured to include a power storage device 2a connected to a load 50 and a power storage device 2b connected to the power storage device 2a.

[0081] 6A, the configuration of each unit is omitted, but the configuration of the power storage devices 2a and 2b is the same as that of the power storage device 2 in embodiment 1. That is, the power storage device 2a includes a power storage PCS 20a and a storage battery unit (not shown). The power storage PCS 20a also includes a power conversion unit 23a, various power input / output terminals such as a load connection unit 25a and a power input unit 24a, a power sensor, a bidirectional DC / DC converter, a control unit (none of which are shown), and the like.

[0082] The power storage device 2b is basically the same as the power storage device 2a, but in the power storage device 2a, a power output terminal 25b similar to the power output terminal connected to the load 50 is connected to the power input section 24a of the power storage device 2a. That is, in this embodiment, the power storage device 2b serves as a power supply source in place of a power generation device.

[0083] In this embodiment, both the power storage device 2a and the power storage device 2b can independently supply power to the load 50. Although not shown, the distributed power system 10 according to this embodiment is also interconnected with a commercial power grid, and can receive power from the grid to charge the storage battery units of the power storage devices 2a and 2b.

[0084] 6A, since the power storage device 2b supplies power to the load 50 via the power storage PCS 20a of the power storage device 2a, there is a risk that the output voltage controls of the power storage PCS 20a of the power storage device 2a and the power storage PCS 20b of the power storage device 2b may interfere with each other. For this reason, the power storage PCS 20a controls the output voltage of the load connection unit 25a with a low response that does not interfere with the output voltage control of the power storage PCS 20b, and when a predetermined condition is met, it increases the discharge power from the power storage device 2a. That is, when there is a sign that the output voltage of the load connection unit 25a will decrease due to a sudden change in the load capacity or a shortage of the remaining capacity (SOC: State Of Charge) of the power storage device 2b, power is discharged from the storage battery unit or the discharge power is increased.

[0085] In this embodiment, the power supply source connected to the power storage device 2a is the power storage device 2b, so the power (amount) that can be output according to the SOC can be easily calculated. For this reason, for example, the power storage PCS 20a may accumulate the power output from the fully charged power storage device 2b to the load 50, and may execute a predetermined process related to the output current value in the load connection unit 25a (discharge power from the power storage device 2a) when the power output from the power storage device 2b exceeds a predetermined threshold.

[0086] Furthermore, when controlling the output of power from both the power storage device 2a and the power storage device 2b to the load 50, the output from the power storage device 2a may be increased if the balance of the output power is lost, on the premise that the control is performed so that the output power is not biased between the power storage devices 2a and 2b (so that the power values ​​are approximately equal). Specifically, the power storage PCS 20a may detect a drop in the output of the power storage device 2b (i.e., the loss of balance in the power output values) from a change in the input voltage value of the power input unit 24a, and may execute a control process to maintain the output voltage value at the load connection unit 25a within a predetermined range.

[0087] The power storage devices 2a and 2b may be configured to be communicatively connected to each other so that they can acquire information from each other (information related to the operation mode, information related to the SOC, information related to input / output power, voltage, current, etc.) With such a configuration, it becomes possible to operate the power storage devices 2a and 2b in an effective manner in cooperation with each other, for example by adjusting the output power of the power storage devices 2a and 2b in a well-balanced manner.

[0088] In such a case, the power storage devices 2a and 2b may communicate information directly or indirectly via a network. Fig. 6B is a schematic diagram of a distributed power system 11 according to such a modification. In Fig. 6B, the same components as those in the distributed power system 10 are denoted by the same reference numerals. As shown in Fig. 6B, the power storage devices 2a and 2b according to this modification are configured to communicate with a network N via gateways (GW) 20a and 29b, respectively. With such a configuration, information can also be input to each power storage device by a controller (not shown) connected to the network N.

[0089] In the above description of the second embodiment, the power supply source connected to the power storage device 2a is the power storage device 2b only, but more power storage devices may be connected in series for operation.

[0090] <Other> The above-described embodiment is merely an example, and the disclosure of the present embodiment may be modified as appropriate within the scope of the gist thereof. The processes and means described in the present disclosure may be freely combined and implemented as long as no technical contradictions arise. For example, the embodiment disclosed in the present embodiment may be applied to an electric vehicle (EV) equipped with a storage battery such as a battery and a power generation mechanism using regenerative energy. Furthermore, the embodiment may be applied to a solar car equipped with a solar power generation module as the power generation mechanism, or a fuel cell car equipped with a fuel cell. Even in such an embodiment, it is possible to control the power output from the power generation mechanism and the storage battery without interference.

[0091] Furthermore, a process described as being performed by one device may be shared and executed by multiple devices. Alternatively, a process described as being performed by different devices may be executed by a single device. In a computer system, the hardware configuration that realizes each function can be flexibly changed.

[0092] Furthermore, in the above embodiment, the integral value processing judgment unit 44 uses the input voltage value in the power input unit 24 to make a judgment regarding the processing of the integral value of the output voltage control unit 41, but the value used for this judgment is not limited to the input voltage value in the power input unit 24 itself. In short, any physical quantity can be used to replace the input voltage value and to timely recognize signs that the output voltage from the load connection unit 25 is deviating from a predetermined range. For example, the above judgment processing may be performed based on the output voltage value or output current value in the independent power output unit 34. Furthermore, a judgment regarding the processing of the integral value of the output voltage control unit 41 may be performed based on the output voltage value or output current value in the load connection unit 25, or the charging power or current value to the storage battery unit 27 and the load power (current). It's fine to do so.

[0093] In the above embodiment, the "predetermined control process" involves changing the current reference value (command value) related to the output power of the load connection unit 25 by manipulating the integral value of the output voltage control unit 41 in a feedforward manner, thereby maintaining the output voltage of the load connection unit 25 within a predetermined range. However, the "predetermined control process" is not limited to this, and other processes may be used. For example, other processes that change the current command value input to the minor control unit 42 may be employed, such as changing the voltage command value in the output voltage control unit 41, manipulating the deviation value input to the output voltage control unit 41 in an FF manner, changing control parameters in the output voltage control unit 41 (e.g., gains of proportional control or integral control), or adding or subtracting from the output value from the output voltage control unit 41 in an FF manner.

[0094] <<Computer-readable recording medium>> A program that causes an information processing device or other machine or device (hereinafter referred to as a computer, etc.) to realize any of the above functions can be recorded on a computer-readable recording medium. Then, by having the computer, etc. read and execute the program from this recording medium, the function can be provided.

[0095] Here, a computer-readable recording medium refers to a recording medium that stores information such as data and programs electrically, magnetically, optically, mechanically, or chemically and that can be read by a computer, etc. Among such recording media, those that can be removed from a computer, etc. include, for example, flexible disks, magneto-optical disks, CD-ROMs, CD-R / Ws, DVDs, Blu-ray discs, DATs, 8mm tapes, memory cards such as flash memory, etc. Furthermore, recording media that are fixed to a computer, etc. include hard disks and ROMs, etc.

[0096] <Appendix 1> A power supply system (1) including a first power supply means (3) and a second power supply means (2), capable of supplying AC power output from at least one of the first power supply means and the second power supply means to a load (50), the first power supply means includes a first power supply source (37), a first power output terminal (34) that outputs AC power to the second power supply means, and a first control means (31) that controls at least an output voltage value associated with the first power output terminal; the second power supply means includes a second power supply source (27), a power input terminal (24) to which AC power output from the first power supply means is input, a second power output terminal (25) to which the AC power is output to the load, and a second control means (21) to control at least an output power value related to the second power output terminal based on an input voltage related to the power input terminal; the second control means controls the AC power input from the power input terminal to be output from at least the second power output terminal, and when a predetermined physical quantity related to the power input to the power input terminal deviates from a predetermined threshold, executes a predetermined control process on an output power value related to the second power output terminal to maintain the output power value related to the second power output terminal at a value corresponding to the load. A power supply system comprising:

[0097] <Appendix 2> a DC power input terminal (912) to which DC power is input; an AC power input terminal (914) to which AC power is input; a power conversion circuit (916) for converting DC power and AC power; a power output terminal (913) that outputs at least one of the AC power input from the AC power input terminal and the AC power converted by the power conversion circuit to a load; a control means (911) for controlling at least an output power value related to the power output terminal based on an input voltage related to the AC power input terminal, The control means when a predetermined physical quantity related to the power input to the AC power input terminal deviates from a predetermined threshold, a predetermined control process is executed on an output power value related to the power output terminal, thereby maintaining the output power value related to the power output terminal at a value corresponding to the load. A power conversion device (910). [Explanation of symbols]

[0098] 1, 10, 11... Distributed Power Systems 2, 2a, 2b...Power storage device 3. Power generation equipment 20, 20a, 20b... Power conditioner (storage PCS) 21, 31 Control unit 22. Bidirectional DC / DC Converter 23 Power conversion section 24, 24a Power input section 25, 25a Load connection 26 Connection point 27 Battery unit 30···Power Conditioner (PV-PCS) 31 Control unit 32 DC / DC converter 33 Power conversion section 34. Independent power output section 37. Solar power generation module 41 Output voltage control section 42 Minor control section 43...Circuit section 50...load 80...Electric power system 82 Distribution board 101 Processor 102...Main memory 103...Auxiliary storage device 104 Communication Interface 105 Input / Output Interface 106···Connection bus

Claims

1. A power supply system including a first power supply means and a second power supply means, capable of supplying AC power output from at least one of the first power supply means and the second power supply means to a load, the first power supply means includes a first power supply source, a first power output terminal that outputs AC power to the second power supply means, and a first control means that controls at least an output voltage value associated with the first power output terminal; the second power supply means includes a second power supply source, a power input terminal to which the AC power output from the first power supply means is input, a second power output terminal from which the AC power is output to the load, and second control means for controlling at least an output power value related to the second power output terminal based on an input voltage related to the power input terminal, the second control means controls the AC power input from the power input terminal to be output from at least the second power output terminal, and, when a predetermined physical quantity related to the power input to the power input terminal deviates from a predetermined threshold, executes a predetermined control process on an output power value related to the second power output terminal, thereby maintaining the output power value related to the second power output terminal at a value corresponding to the load. A power supply system comprising:

2. the second control means includes a voltage control unit that integrates a deviation between a predetermined output voltage command value and an output voltage value related to the power output from the second power output terminal, and calculates an operation amount related to an output current value related to the second power output terminal using the output value output from the voltage control unit, the predetermined control process includes changing an integral value of the voltage control unit.

2. The power supply system according to claim 1 .

3. the second control means sets the integral value of the voltage control unit to a predetermined value when a voltage value related to the power input to the power input terminal exceeds a predetermined threshold value; 3. The power supply system according to claim 2.

4. when a voltage value related to the power input to the power input terminal falls below a predetermined threshold, the second control means changes the integral value of the voltage control unit using an output current value related to the power output from the second power output terminal.

4. The power supply system according to claim 2 or 3.

5. the second power supply means is a power storage device having a storage battery as the second power supply source and a power storage power conditioner connected to the storage battery, When a voltage value related to the power input to the power input terminal falls below a predetermined threshold, power is discharged from the storage battery.

5. The power supply system according to claim 4.

6. The first power supply means includes: a power generation device including a solar power generation module as the first power supply source and a solar power generation power conditioner connected to the solar power generation module; 6. The power supply system according to claim 5.

7. a DC power input terminal to which DC power is input; an AC power input terminal to which AC power is input; a power conversion circuit that converts DC power and AC power; a power output terminal that outputs at least one of the AC power input from the AC power input terminal and the AC power converted by the power conversion circuit to a load; a control means for controlling at least an output power value related to the power output terminal based on an input voltage related to the AC power input terminal, The control means when a predetermined physical quantity related to the power input to the AC power input terminal deviates from a predetermined threshold, a predetermined control process is executed on an output power value related to the power output terminal, thereby maintaining the output power value related to the power output terminal at a value corresponding to the load. A power conversion device comprising:

8. the control means includes a voltage control unit that integrates a deviation between a predetermined output voltage command value and an output voltage value related to the power output from the power output terminal, and calculates an operation amount related to an output current value related to the power output terminal using the output value output from the voltage control unit, the predetermined control process includes changing an integral value of the voltage control unit. The power conversion device according to claim 7 .

9. The DC power input terminal is connected to a storage battery as a power supply source, the AC power input terminal is connected to a power supply means having a power supply source different from the storage battery; the control means performs control to discharge power from the storage battery and output it from the power output terminal when a voltage value related to the power input to the AC power input terminal falls below a predetermined threshold.

9. The power conversion device according to claim 7 or 8.

Images