JP6363412B2 - Power conditioner and power control method - Google Patents

Description

  The present invention relates to a power conditioner connected to a power storage device and a power control method thereof.

  In recent years, power generation systems using natural energy, such as solar power generation systems, are being introduced into homes for general households or industrial facilities. In these power generation systems, the generated power is used as a power source for electronic devices and the like. At present, an electric power purchase system for selling generated electric power and purchasing it by an electric power company has been established in order to make the electric power generation system using natural energy more popular. Therefore, the generated power may flow backward to the commercial power system.

  By the way, in recent years, an increasing number of users have a strong awareness of environmental issues. Such a user gives priority to consumption of the generated power using natural energy in the individual power system rather than selling power to the commercial power system, and tries to suppress the use of the commercial power system. As such means, for example, as in Patent Document 1, a power storage device may be connected to a power generation system using natural energy. In the power generation system of Patent Document 1, the power conditioner converts the power generated by the solar cell module from direct current to alternating current and supplies it to the load. The power storage device is connected to the power conditioner via a bidirectional DC / DC converter so as to be capable of storing and discharging.

  When giving priority to the consumption of generated power within an individual power system, for example, the amount of power sold to the commercial power system is set in advance. When the generated power obtained by subtracting the amount of power sold exceeds the power consumed in the individual power system, the surplus power is stored in the power storage device. Further, when the power consumption is less than the power consumption, the discharge power of the power storage device is supplied to the insufficient power.

JP2012-161189A

  However, in the power purchase system, it is generally prohibited to sell the power stored in the power storage device by flowing backward to the commercial power system. Therefore, in the power generation system to which the power storage device is connected, it is necessary to control the power so that the discharge power of the power storage device does not flow backward. On the other hand, when priority is given to the consumption of generated power within individual power systems, it is also required to use the generated power while suppressing the use of the commercial power system (that is, selling and buying power). In such a case, the power control of the power generation system becomes very complicated.

  With respect to this problem, Patent Document 1 assumes a power system in which a load is connected to the output end of the power conditioner, and does not assume a power system in which a commercial power system is connected. That is, Patent Document 1 does not consider such a problem at all.

  The present invention has been made in view of such a situation, and power that can use generated power while suppressing the use of the commercial power system without causing reverse power flow from the power storage device to the commercial power system. An object is to provide a conditioner and a power control method.

  In order to achieve the above object, a power conditioner according to an aspect of the present invention includes a bidirectional power conversion unit provided between a first power generation device and a commercial power system, a second power generation device and a power storage device, Power determination for determining whether or not the generated power of the first power generator connected to the transmission path between the bidirectional power converter and the commercial power system is greater than or equal to the power consumption of the power load connected to the transmission path And the power determination unit determine that the generated power of the first power generation device is greater than or equal to the power consumption, the bidirectional power conversion unit in the forward conversion direction in which the power is converted from the transmission path side to the power storage device side. And a conversion control unit that sets a power conversion direction.

  The power conditioner having the above configuration further includes a power detection unit that detects a power value transmitted between the transmission path and the commercial power system, and the conversion control unit uses the power determination unit to generate power from the first power generator. When it determines with it being above, it is good also as a structure which sets the electric power converted by the bidirectional | two-way power converter in a forward conversion direction according to an electric power value so that an electric power value may become a 1st target value.

  In the power conditioner having the above configuration, the conversion control unit reversely converts the power from the power storage device side to the transmission path side when the power determination unit does not determine that the generated power of the first power generation device is greater than or equal to the power consumption. The power conversion direction of the bidirectional power conversion unit may be set as the conversion direction.

  The power conditioner having the above configuration further includes a storage / discharge power conversion unit provided between the power storage device and the bidirectional power conversion unit, and the power determination unit has a power conversion direction of the bidirectional power conversion unit in a reverse conversion direction. If it is set, it is further determined whether or not the total power of the generated power of the first power generator and the generated power of the second power generator is greater than or equal to the power consumption, and the power conversion direction of the storage / discharge power converter Is set in the first direction in which power conversion is performed from the bidirectional power conversion unit side to the power storage device side when the total power is determined to be greater than or equal to the power consumption by the power determination unit. May be set in the second direction in which power is converted from the power storage device side to the bidirectional power conversion unit side.

  Moreover, in the power conditioner having the above configuration, when the power determination unit determines that the total power is greater than or equal to the power consumption, the storage discharge power conversion unit converts the first power value so that the power value becomes the second target value. It is good also as a structure by which the electric power converted into a direction is set according to an electric power value.

  In order to achieve the above object, a power control method according to an aspect of the present invention includes a bidirectional power conversion unit provided between a first power generation device and a commercial power system, a second power generation device, and a power storage device. In the step of determining whether or not the generated power of the first power generator connected to the transmission path to the commercial power system is greater than or equal to the power consumption of the power load connected to the transmission path A step of setting the power conversion direction of the bidirectional power conversion unit in a forward conversion direction in which power is converted from the transmission path side to the power storage device side when it is determined that the generated power of the first power generation device is greater than or equal to the power consumption; It is set as the structure provided with.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production electric power can be utilized, suppressing utilization of a commercial power grid, without making electric power flow back from a power storage apparatus to a commercial power grid.

It is a block diagram which shows the structural example of a solar energy power generation system. It is a flowchart for demonstrating the electric power control process in a clean mode. It is a block diagram which shows the other structural example of a solar power generation system. It is a block diagram which shows the structural example of a wind power generation system.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
First, the first embodiment will be described using the solar power generation system 100 as an example. FIG. 1 is a block diagram illustrating a configuration example of the solar power generation system 100. The solar power generation system 100 is a power system having a solar cell module 1 and a storage battery 2, and is a distributed power source that supplies power by a power generation system that converts sunlight into electric power. The photovoltaic power generation system 100 is connected to the commercial power system E via the power receiving point R. A power load L is also connected to the power receiving point R. The power load L is, for example, a domestic appliance or a factory equipment, and consumes power supplied to the power receiving point R in the solar power generation system 100.

  When this solar power generation system 100 operates in the normal mode, at least one of the power generated by the solar cell module 1 and the power supplied from the commercial power system E can be stored in the storage battery 2. In the following, the DC power output from the solar cell module 1 is referred to as generated power. The power stored in the storage battery 2 can be used, for example, when a power outage or a temporary protrusion of power consumption at the power load L occurs, and responds to these situations by discharging from the storage battery 2. Further, in the photovoltaic power generation system 100, the generated power can be converted from direct current to alternating current, and reversely flowed (output) to the commercial power system E via the power receiving point R, and the power can be sold to the power company. It has become.

  Moreover, the solar power generation system 100 includes a clean mode that is a special usage mode in addition to the normal mode that is a general usage mode. When the solar power generation system 100 operates in the clean mode, the power consumption in the solar power generation system 100 is basically covered by the generated power. When the generated power is sufficient and exceeds the power consumption of the power load L, the generated power is charged to the storage battery 2 without flowing backward to the commercial power system E. Moreover, the photovoltaic power generation system 100 can discharge the storage battery 2 in order to make up for the insufficient power when the generated power falls below the power consumption. Thus, in the clean mode of the photovoltaic power generation system 100, the use of the commercial power system E is suppressed. Below, the case where the solar power generation system 100 is set to the clean mode is demonstrated.

  Next, the configuration of the solar power generation system 100 will be described. As shown in FIG. 1, the solar power generation system 100 includes a solar cell module 1, a storage battery 2, a first power conditioner 3, a second power conditioner 4, and a controller 5.

  The solar cell module 1 is a power generation device that includes a plurality of solar cells, generates power by receiving sunlight, and outputs DC power. In the present embodiment, the solar cell module 1 includes a first solar cell module 1a and a second solar cell module 1b.

  The storage battery 2 is a power storage device including a rechargeable secondary battery that is stored using generated power. The storage battery 2 can be stored using electric power supplied from the commercial power system E, but in the clean mode, the storage using the electric power is basically suppressed. Moreover, the storage battery 2 can discharge the direct-current electric power according to the stored electric power (namely, electric storage amount wa). In the following, DC power supplied to the storage battery 2 is referred to as stored power, and DC power output from the storage battery 2 is referred to as discharge power. For example, a lithium secondary battery, a nickel hydrogen battery, a nickel cadmium battery, or a lead battery can be used as the storage battery 2.

  The first and second power conditioners 3 and 4 are power generation control devices that control the operating point of the solar cell module 1 so that the generated power becomes maximum, for example, by MPPT (Maximum Power Point Tracking) control. The first power conditioner 3 performs MPPT control on the first solar cell module 1a, and the second power conditioner 4 performs MPPT control on the second solar cell module 1b. The second power conditioner 4 also functions as a storage / discharge control device for the storage battery 2, and supplies stored power to the storage battery 2 or receives discharge power from the storage battery 2.

  The first power conditioner 3 includes a DC / DC converter 31, an inverter 32, a capacitor 33, a first communication unit 35, a first memory 36, and a first IC 38. The DC / DC converter 31 and the inverter 32 are connected by the first bus line BL1.

  The DC / DC converter 31 is a direct current converter connected to the first solar cell module 1a, converts the generated power into direct current power having a predetermined voltage value, and outputs it to the first bus line BL1. Further, the DC / DC converter 31 prevents a reverse current from flowing through the first solar cell module 1a. The inverter 32 is connected to a transmission path P between the power receiving point R and the second power conditioner 4 (a bidirectional inverter 42 to be described later), and converts the DC power input from the first bus line BL1 into a commercial power system. The power is converted into AC frequency power corresponding to E and output to the transmission path P. The capacitor 33 is connected to the first bus line BL1, and removes or reduces fluctuations in the bus voltage value of the power flowing through the first bus line BL1. The first communication unit 35 is a communication interface that performs wireless communication or wired communication with the controller 5. The first memory 36 is a non-volatile storage medium that temporarily stores information such as control information and programs used by each component (particularly, the first IC 38) of the first power conditioner 3. The first IC 38 is a control unit that controls each component of the first power conditioner 3 using information, a program, and the like stored in the first memory 36.

  Next, the second power conditioner 4 includes a DC / DC converter 41, a bidirectional inverter 42, a capacitor 43, a bidirectional DC / DC converter 44, a second communication unit 45, a second memory 46, It has a watt-hour meter 47 and a second IC 48. Note that the DC / DC converter 41, the bidirectional inverter 42, and the bidirectional DC / DC converter 44 are connected to each other via the second bus line BL2.

  The DC / DC converter 41 is a direct current converter connected to the second solar cell module 1b. The DC / DC converter 41 is provided between the second solar cell module 1b and the second bus line BL2, and converts the generated power of the second solar cell module 1b into DC power having a predetermined voltage value, thereby converting the second bus line BL2. Output to. Further, the DC / DC converter 41 prevents a reverse current from flowing through the second solar cell module 1b.

  The bidirectional inverter 42 is a bidirectional power converter provided between the first solar cell module 1 a and the commercial power system E, the second solar cell module 1 b and the storage battery 2. One end of the bidirectional inverter 42 is connected to the second bus line BL2, and the other end is connected to the power receiving point R through the transmission path P. Hereinafter, AC / DC conversion of power from the transmission path P to the second bus line BL2 by the bidirectional inverter 42 is referred to as forward conversion, and this power conversion direction is referred to as a forward conversion direction a. That is, the forward conversion direction a is a power conversion direction in which power is converted from the power receiving point R side to the storage battery 2 side. In addition, the bidirectional inverter 42 performing DC / AC conversion of power from the second bus line BL2 to the transmission path P is referred to as reverse conversion, and this power conversion direction is referred to as reverse conversion direction b. That is, the reverse conversion direction b is a power conversion direction in which power is converted from the storage battery 2 side to the power receiving point R side.

  When the bidirectional inverter 42 is set in the forward conversion direction a, the alternating current power input from the transmission path P is forward converted and output to the second bus line BL2. In addition, when the bidirectional inverter 42 is set in the reverse conversion direction b, the direct current power input from the second bus line BL2 is converted into the power of the alternating frequency according to the power receiving point R (and the commercial power system E). Inversely transforms and outputs to transmission path P. As will be described later, these operations are controlled by the second IC 48.

  The capacitor 43 is connected to the second bus line BL2, and removes or reduces fluctuations in the bus voltage value of the power flowing through the second bus line BL2.

  The bidirectional DC / DC converter 44 is a stored power conversion unit connected between the storage battery 2 and the bidirectional inverter 42. One end of the bidirectional DC / DC converter 44 is connected to the storage battery 2, and the other end is connected to the second bus line BL2. Hereinafter, the DC / DC conversion of power from the second bus line BL2 to the storage battery 2 by the bidirectional DC / DC converter 44 is referred to as storage conversion, and this power conversion direction is referred to as storage direction A (first direction). Call it. That is, the storage direction A is a power conversion direction in which power is converted from the bidirectional inverter 42 side to the storage battery 2 side. In addition, the bidirectional DC / DC converter 44 performing DC / DC conversion of power from the storage battery 2 to the second bus line BL2 is referred to as discharge conversion, and this power conversion direction is referred to as a discharge direction B (second direction). That is, the discharge direction B is a power conversion direction in which power is converted from the storage battery 2 side to the bidirectional inverter 42 side.

  When the bidirectional DC / DC converter 44 is set in the storage direction A, the direct current power flowing through the second bus line BL2 is converted into direct current stored power suitable for the storage battery 2 and output to the storage battery 2. In addition, when the bidirectional DC / DC converter 44 is set in the discharge direction B, the discharge power of the storage battery 2 is converted into direct current power and output to the second bus line BL2. As will be described later, these operations are controlled by the controller 5.

  The second communication unit 45 is a communication interface that performs wireless communication or wired communication with the controller 5. The second communication unit 45 transmits, for example, a determination result of a watt-hour meter 47 (power determination unit) described later and a comparison result of the power comparison unit 481 to the controller 5.

  The second memory 46 is a non-volatile storage medium that holds stored information non-temporarily without supplying power. The second memory 46 stores control information, programs, and the like used by each functional element (particularly the second IC 48) of the second power conditioner 4.

  The watt-hour meter 47 is a power detection unit that detects a power value W of power transmitted between the photovoltaic power generation system 100 and the commercial power system E via the power reception point R. Detects the power sold. In addition, the watt-hour meter 47 functions as a power determination unit. For example, the generated power of the first solar cell module 1a connected to the transmission path P between the bidirectional inverter 42 and the commercial power system E is the transmission path. It is determined whether or not the power consumption of the power load L connected to P is equal to or higher. When the power conversion direction of the bidirectional inverter 42 is set to the reverse conversion direction b, the sum of the generated power of the first solar cell module 1a and the generated power of the second solar cell module 1b is the power load L. It is further determined whether or not the power consumption is greater than or equal to.

  In addition, although it is sufficient to have a power measuring device that can directly and individually measure the generated power of the first and second solar cell modules 1a and 1b, the power at the power receiving point R can be obtained without directly measuring the generated power. Depending on the state of each converter, the relationship between the generated power and the power consumption of the power load L may be determined.

  The processing result in the watt-hour meter 47 is output to the second IC 48. The watt hour meter 47 may be incorporated in the second power conditioner 4 or may be externally attached to the second power conditioner 4.

  The watt-hour meter 47 includes a power sales meter 471 and a purchased power meter 472. Each of the electricity sales meter 471 and the electricity purchase meter 472 is a power amount measuring device with a reverse rotation prevention function that detects power transmitted in one direction. Although each of the electricity sales meter 471 and the electricity purchase meter 472 is not particularly limited, for example, an energy meter such as an induction energy meter, a reactive energy meter, and an electronic energy meter can be used. In addition, the electricity sales meter 471 and the electricity purchase meter 472 may be provided as physically separated devices, or may be provided in the same device as shown in FIG.

  When power is transmitted from the photovoltaic power generation system 100 to the commercial power grid E at the power receiving point R, the power sales meter 471 detects that the photovoltaic power generation system 100 is selling power to the commercial power grid E. Hereinafter, the transmission direction in which power is transmitted from the photovoltaic power generation system 100 to the commercial power system E at the power receiving point R is referred to as a power selling direction (first transmission direction). The electric power sales meter 471 further detects the electric power value W of electric power sold from the photovoltaic power generation system 100 (particularly the first solar cell module 1a) to the commercial electric power system E as the electric power sales quantity, and integrates the electric power sales quantity. . Then, the power sales meter 471 transmits these results to the second IC 48.

  When power is transmitted from the commercial power system E to the solar power generation system 100 at the power receiving point R, the power purchase meter 472 detects that the solar power generation system 100 is purchasing power from the commercial power system E. Hereinafter, the transmission direction in which power is transmitted from the commercial power system E to the photovoltaic power generation system 100 at the power receiving point R is referred to as a power purchase direction (second transmission direction). The power purchase meter 472 further detects the power value of the power purchased from the commercial power system E as the power purchase amount, and integrates the power purchase amount. Then, the power purchase meter 472 transmits these results to the second IC 48.

  Note that the watt-hour meter 47 is configured such that when the watt-hour meter 471 detects the power value W> 0, or there is no power transmission via the power receiving point R, the watt-hour meter 471 and the purchased watt-hour meter 472 have power values. When W is not detected (power value W = 0), it is determined that the power transmission direction at the power receiving point R is the power selling direction. When power purchase meter 472 detects power value W> 0, it determines that the power transmission direction at power receiving point R is the power purchase direction. Therefore, the watt-hour meter 47 also functions as a power transmission direction detection unit that detects the power transmission direction between the photovoltaic power generation system 100 and the commercial power system E at the power receiving point R.

  The second IC 48 is a control unit that controls each component of the second power conditioner 4 using information, a program, and the like stored in the second memory 46. The second IC 48 includes a power comparison unit 481 and a first conversion control unit 482 as functional components.

  The power comparison unit 481 compares the power value W transmitted via the power receiving point R with the first target value W1 and the second target value W2 different from the first target value W1. The first and second target values W1 and W2 are preset values, and are set values that can be changed by user input in the controller 5 described later. For example, each of the target values W1 and W2 is a target value of electric power sold to the commercial power system E. Note that these may be target values for the power to be purchased. The first target value W1 is set to 200 [W], for example, and the second target value W2 is set to 400 [W], for example. That is, 0 <W1 <W2. The first target value W1 and the second target value W2 may be the same.

  The first conversion control unit 482 controls the bidirectional inverter 42 based on the determination result of the watt-hour meter 47 (power determination unit) and the comparison result of the power comparison unit 481, and in particular, the power conversion direction and the power conversion amount. To control. The first conversion control unit 482 is an example of a part of the conversion control unit of the present invention.

  For example, consider a case where the watt-hour meter 47 determines that the generated power of the first solar cell module 1a supplied to the transmission path P is greater than or equal to the power consumption of the power load L. In this case, the first conversion control unit 482 sets the power conversion direction of the bidirectional inverter 42 to the forward conversion direction a, and sets the power conversion direction of the bidirectional DC / DC converter 44 to the power storage direction A. With this setting, surplus power at the power receiving point R can be supplied to the storage battery 2 to be stored. Therefore, the solar power generation system 100 can preferentially consume the generated power of the solar cell module 1 while suppressing the power sale to the commercial power system E.

  On the other hand, consider a case where the watt-hour meter 47 does not determine that the generated power of the first solar cell module 1a supplied to the transmission path P is greater than or equal to the power consumption of the power load L. In this case, the first conversion control unit 482 sets the power conversion direction of the bidirectional inverter 42 to the reverse conversion direction b.

  In addition, after such setting of the reverse conversion direction b, in the watt hour meter 47, the total power (hereinafter, referred to as the power generated by the first solar cell module 1b and the power generated by the second solar cell module 1b). When it is determined that the total power) is greater than or equal to the power consumption of the power load L, the power conversion direction of the bidirectional DC / DC converter 44 is set to the power storage direction A as described later. On the other hand, after the setting of the reverse conversion direction b, the watt hour meter 47 does not determine that the total power generated by the first and second solar cell modules 1a and 1b is greater than or equal to the power consumption of the power load L. As will be described later, the power conversion direction of the bidirectional DC / DC converter 44 is set to the discharge direction B. With this setting, for example, at least a part of the generated power of the second solar cell module 1b can be supplied to the power receiving point R. Furthermore, the discharge power of the storage battery 2 can be supplied to the power receiving point R. Therefore, the solar power generation system 100 can supply the power generated by the second solar cell module 1b and the discharge power of the storage battery 2 to the power receiving point R in order to compensate for the power shortage at the power receiving point R. Power purchase from the system E can be suppressed.

  Thus, the photovoltaic power generation system 100 includes the bidirectional DC / DC converter 44 connected to the storage battery 2, and the bidirectional inverter 42 connected to the second solar cell module 1 b and the bidirectional DC / DC converter 44. By controlling the power consumption of the commercial power system E, the power generated by the first solar cell module 1a and the second solar cell module 1b can be used efficiently.

  Further, the first conversion control unit 482 determines that the generated power of the first solar cell module 1a is greater than or equal to the power consumption of the power load L by the watt-hour meter 47, and sets the bidirectional inverter 42 in the forward conversion direction a. If it is, the power that is forward-converted by the bidirectional inverter 42 is set according to the power value W transmitted through the power receiving point R. For example, the first conversion control unit 482 reduces the power conversion amount in the bidirectional inverter 42 when the power value W becomes smaller than the second target value W2. On the other hand, the first conversion control unit 482 increases the amount of power conversion in the bidirectional inverter 42 when the power value W becomes larger than the second target value W2.

  If it carries out like this, the electric power sold to the commercial power grid | system E via the receiving point R can be controlled so that it may become 2nd target value W2. In addition, the forward converted power is stored in the storage battery 2. Therefore, the generated power can be preferentially consumed in the solar power generation system 100.

  Next, the controller 5 is an external control device that controls the second power conditioner 4 and receives user input. The controller 5 includes an input unit 51, a third communication unit 52, a third memory 53, and a third IC 54.

  The input unit 51 receives a user input and outputs an input signal corresponding to the user input to the third IC 54. The input unit 51 receives, for example, user input for operating the photovoltaic power generation system 100 in the clean mode.

  The third communication unit 52 is a communication interface that performs wireless communication or wired communication with the first communication unit 35 of the first power conditioner 3 and the second communication unit 45 of the second power conditioner 4. For example, the third communication unit 52 receives the determination result of the watt hour meter 47 and the comparison result of the power comparison unit 481 from the second communication unit 45.

  The third memory 53 is a non-volatile storage medium that holds stored information in a non-temporary manner without supplying power. The third memory 53 stores control information, programs, and the like used by the functional elements of the controller 5 (particularly, the third IC 54).

  The third IC 54 is a control unit that controls each component of the controller 5 using information, a program, and the like stored in the third memory 53. The third IC 54 includes a storage amount monitoring unit 541 and a second conversion control unit 542 as functional components.

  The storage amount monitoring unit 541 monitors the storage amount wa of the storage battery 2. For example, the storage amount monitoring unit 541 monitors whether or not the storage amount wa is less than the storage capacity wc.

  The second conversion control unit 542 controls the bidirectional DC / DC converter 44. In particular, the second conversion control unit 542 performs power conversion of the bidirectional DC / DC converter 44 based on the determination result of the watt-hour meter 47, the comparison result of the power comparison unit 481, and the monitoring result of the storage amount monitoring unit 541. Control the direction and power conversion operation. The second conversion control unit 542 is an example of a part of the conversion control unit of the present invention.

  For example, the watt hour meter 47 does not determine that the generated power of the first solar cell module 1a is greater than or equal to the power consumption of the power load L, the power conversion direction of the bidirectional inverter 42 is set to the reverse conversion direction b, and Consider a case where it is determined that the total power generated by the first and second solar cell modules 1a and 1b is greater than or equal to the power consumption of the power load L. In this case, the second conversion control unit 542 sets the power conversion direction of the bidirectional DC / DC converter 44 to the power storage direction A. Further, in order to bring the power value W at the power receiving point R closer to the first target value W1, the second conversion control unit 542 sets the power conversion amount in the storage direction A in the bidirectional DC / DC converter 44 according to the power value W. To set. For example, when the power value W becomes smaller than the first target value W1, the power conversion amount in the bidirectional DC / DC converter 44 is decreased. On the other hand, the second conversion control unit 542 increases the power conversion amount in the bidirectional DC / DC converter 44 when the power value W becomes equal to or higher than the first target value W1.

  On the other hand, when it is not determined that the total power generated by the first and second solar cell modules 1a and 1b is greater than or equal to the power consumption of the power load L, the second conversion control unit 542 includes the bidirectional DC / DC converter 44. The power conversion direction is set to the discharge direction B.

  In this way, when the generated power of the first solar cell module 1a is greater than or equal to the power consumption of the power load L, both the power value W transmitted through the power receiving point R becomes the second target value W2. The directional DC / DC converter 44 converts at least a part of the generated power of the first solar cell module 1a and the generated power of the second solar cell module 1b, which are forward-converted by the bidirectional inverter 42, and stores them in the storage battery 2. it can. In addition, the generated power of the first solar cell module 1a is less than the power consumption of the power load L, and the total power of the generated power of the first and second solar cell modules 1a and 1b is greater than or equal to the power consumption of the power load L. In this case, at least a part of the generated power of the second solar cell module 1b can be converted and stored in the storage battery 2 so that the power value W becomes the first target value W1. In addition, in this way, by making a difference between the second target value W2 of power sale at the bidirectional inverter 42 and the first target value W1 of power sale at the bidirectional DC / DC converter 44, the power load L Even when the power consumption or the generated power fluctuates, the power conversion amount in the forward conversion direction a of the bidirectional inverter 42 is preferentially fluctuated to increase or decrease the storage amount of the generated power of the first solar cell module 1a. Thereby, it is possible to preferentially store the power generated in the second solar cell module 1 b in the storage battery 2, and to suppress unnecessary fluctuations in the power conversion amount in the bidirectional DC / DC converter 44.

  In addition, when the monitoring result of the storage amount monitoring unit 541 indicates that the storage amount wa of the storage battery 2 reaches the storage capacity wc, the storage battery 2 is overcharged if it is further stored. In this case, the second conversion control unit 542 sets the power conversion amount in the bidirectional DC / DC converter 44 to 0 and stops the power conversion operation in the bidirectional DC / DC converter 44. Alternatively, the bidirectional DC / DC converter 44 may be set in the discharge direction B and the bidirectional inverter 42 may be set in the reverse conversion direction b. If it carries out like this, the overcharge of the storage battery 2 can be prevented, the deterioration of the electrical storage capability and the fall of a lifetime can be suppressed, and the breakage etc. can also be prevented.

  Next, power control processing in the clean mode of the photovoltaic power generation system 100 will be described. FIG. 2 is a flowchart for explaining power control processing in the clean mode. The power control process of FIG. 2 is started when the second power conditioner 4 is set to the clean mode, and is ended when the clean mode is released, for example.

  First, the watt-hour meter 47 determines whether or not the power supplied from the photovoltaic power generation system 100 to the transmission point P between the power receiving point R and the both inverters 42 is equal to or higher than the power consumption of the power load L (step). S101). For example, if the power conversion amount of the bidirectional inverter 42 is zero, the generated power of the first solar cell module 1a is supplied to the transmission path P. In this case, when the watt hour meter 47 detects the power value W of the power transmitted from the photovoltaic power generation system 100 to the commercial power system E at the power receiving point R, the generated power of the first solar cell module 1a is greater than or equal to the power consumption. Judge that there is. On the other hand, when the watt hour meter 47 detects the power value of the power transmitted from the commercial power system E to the photovoltaic power generation system 100 at the power receiving point R, the generated power of the first solar cell module 1a is equal to or higher than the power consumption. Is not judged.

  If it is not determined that the generated power supplied from the solar power generation system 100 to the transmission path P is greater than or equal to the power consumption (NO in step S101), the process proceeds to step S107 described later.

  On the other hand, when it is determined that the power supplied from the solar power generation system 100 to the transmission path P is greater than or equal to the power consumption (YES in step S101), the power consumption is supplied from the solar power generation system 100 to the transmission path P. It can be fully covered with electricity. In this case, in order to store surplus power in the storage location 2, the power conversion direction of the bidirectional inverter 42 is set to the forward conversion direction a (step S102), and the power conversion direction of the bidirectional DC / DC converter 44 is the storage direction. A is set (step S103).

  Then, it is determined whether or not the power value W transmitted to the commercial power system E via the power receiving point R exceeds the second target value W2 (step S104). When it is determined that W> W2 (YES in step S104), the amount of power conversion in the forward conversion direction a in the bidirectional inverter 42 is controlled to increase (step S105). Then, the process proceeds to step S111. If it is not determined that W> W2 (NO in step S104), control is performed such that the amount of power conversion in the forward conversion direction a in the bidirectional inverter 42 decreases (step S106). And a process progresses to step S111 mentioned later.

  Next, a case where NO is determined in step S101 (a case where the generated power supplied from the solar power generation system 100 to the transmission path P is not determined to be greater than or equal to the power consumption) will be described. In this case, the power supplied from the solar power generation system 100 to the transmission path P is insufficient with respect to the power consumption in the solar power generation system 100. For example, if the power conversion amount of the bidirectional inverter 42 is zero, the watt hour meter 47 has insufficient power generated by the first solar cell module 1 a with respect to the power consumed in the solar power generation system 100. It is determined. Therefore, the power conversion direction of the bidirectional inverter 42 is set to the reverse conversion direction b in order to suppress the power purchased from the commercial power system E (step S107).

  And it is determined by the electric energy meter 47 whether the electric power supplied to the transmission path P from the solar power generation system 100 is more than the power consumption of the electric power load L (step S108). For example, if the power conversion direction of the bidirectional inverter 42 is set to the reverse conversion direction b and the power conversion amount of the bidirectional DC / DC converter 44 is zero, the power generation of the first solar cell module 1a is performed on the transmission path P. Electric power and electric power generated by the second solar cell module 1b are supplied. In this case, when the watt hour meter 47 detects the power value W of the power transmitted from the photovoltaic power generation system 100 to the commercial power system E at the power receiving point R, the watt hour meter 47 determines that the total power is equal to or higher than the power consumption. As described above, the total power is the sum of the generated power of the first solar cell module 1a and the generated power of the second solar cell module 1b. On the other hand, when the power meter 47 detects the power value of the power transmitted from the commercial power system E to the solar power generation system 100 at the power receiving point R, the watt hour meter 47 does not determine that the total power is greater than or equal to the power consumption.

  When it is not determined that the power supplied from the photovoltaic power generation system 100 to the transmission path P is greater than or equal to the power consumption (NO in step S108), the first and second power consumptions in the photovoltaic power generation system 100 are The total power supplied from the solar cell modules 1a and 1b to the transmission path P is insufficient. In this case, the power conversion direction of the bidirectional DC / DC converter 44 is set to the discharge direction B in order to further suppress the power purchased from the commercial power system E (step S109). With this setting, the transmission path P is supplied with the generated power of the first solar cell module 1a, the generated power of the second solar cell module 1b, and the discharge power of the storage battery 2. Then, the process returns to step S108.

  On the other hand, when it is determined that the power supplied from the photovoltaic power generation system 100 to the transmission path P is greater than or equal to the power consumption (YES in step S108), the power consumption is transmitted from the first and second solar cell modules 1a and 1b. The total power supplied to the path P can be sufficiently covered. In this case, the power conversion direction of bidirectional DC / DC converter 44 is set to storage direction A (step S110). Then, the process proceeds to step S111.

  In step S111, it is determined whether or not the power value W transmitted to the commercial power grid E via the power receiving point R is equal to or greater than the first target value W1. When it is determined that W ≧ W1 (YES in step S111), control is performed such that the amount of power conversion in the storage direction A in the bidirectional DC / DC converter 44 increases (step S112). Then, the process returns to step S101. If it is not determined that W ≧ W1 (NO in step S111), control is performed such that the power conversion amount in the storage direction A in the bidirectional DC / DC converter 44 is reduced (step S113). Then, the process returns to step S101.

  In step S112, the amount of power conversion is controlled to increase. However, the upper limit value of the power stored in the storage battery 2 is bidirectional when the power conversion direction of the bidirectional inverter 42 is the forward conversion direction a. A total value of the power forward-converted by the inverter 42 and the generated power of the second solar cell module 1b may be used.

Second Embodiment
Next, a second embodiment will be described. In the second embodiment, a power generation device such as the second solar cell module 1 b is not connected between the storage battery 2 and the bidirectional inverter 42. The rest is the same as in the first embodiment. Hereinafter, a configuration different from the first embodiment will be described. Moreover, the same code | symbol is attached | subjected to the component similar to 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 3 is a block diagram illustrating another configuration example of the solar power generation system 100. The solar power generation system 100 shown in FIG. 3 has the same configuration as FIG. 1 except that the second solar cell module 1b and the DC / DC converter 41 are not included. Accordingly, the first power conditioner 3 functions as a power generation control device, and the second power conditioner 4 functions as a storage / discharge control device for the storage battery 2. Even in such a configuration, similarly to the first embodiment, the generated power of the solar cell module 1 is suppressed by suppressing the use of the commercial power system E without causing reverse power flow from the storage battery 2 to the commercial power system E. Can be used.

<Third Embodiment>
Next, a third embodiment will be described. In the third embodiment, the distributed power source performs power generation using renewable energy other than sunlight (natural energy power generation such as wind, hydropower, geothermal, biomass, solar heat, waste power generation, etc.). The rest is the same as in the first embodiment. Hereinafter, a configuration different from the first embodiment will be described. Moreover, the same code | symbol is attached | subjected to the component similar to 1st Embodiment, and the description is abbreviate | omitted.

  Here, the wind power generation system 100a will be described as an example. The wind power generation system 100a is a distributed power source that supplies power by a power generation method using wind power. FIG. 4 is a block diagram illustrating a configuration example of the wind power generation system 100a. As shown in FIG. 4, the wind power generation system 100 a includes a wind power generator 10 in addition to the storage battery 2, the first power conditioner 3, the second power conditioner 4, and the controller 5. The first power conditioner 3 includes an AC / DC converter 31a in addition to the inverter 32, the capacitor 33, the first communication unit 35, the first memory 36, and the first IC 38. The second power conditioner 4 includes an AC / DC converter in addition to the bidirectional inverter 42, the capacitor 43, the bidirectional DC / DC converter 44, the second communication unit 45, the second memory 46, and the second IC 48. 41a.

  The wind power generator 10 includes a first wind power generator 10a and a second wind power generator 10b. The first and second wind power generators 10a and 10b include, for example, a horizontal axis propeller type windmill and a generator (not shown) driven by the rotation of the windmill. When the windmill blade receives wind, the windmill rotates. The rotational force is transmitted to the generator, and AC power is output from the generator as generated power. The first wind power generator 10 a is connected to the first power conditioner 3, and the second wind power generator 10 b is connected to the second power conditioner 4.

  The AC / DC converters 31a and 41a of the first and second power conditioners 3 and 4 are direct-current converters connected to the first and second wind power generators 10a and 10b, respectively. Each of the AC / DC converters 31a and 41a converts AC generated power into DC power, and further prevents reverse current from flowing through the first and second wind power generators 10a and 10b.

  In the configuration of FIG. 4, the wind power generation system 100a includes the second wind power generation device 10b and the AC / DC converter 41a, but the present invention is not limited to this example. Similarly to FIG. 3 of the second embodiment, the wind power generation system 100a may not include the second wind power generation apparatus 10b and the AC / DC converter 41a. Even in this case, similarly to the configuration of FIG. 4, the use of the generated power of the wind power generator 10 is used while suppressing the use of the commercial power system E without causing reverse power flow from the storage battery 2 to the commercial power system E. be able to.

  The embodiment of the present invention has been described above. The above-described embodiment is an exemplification, and various modifications can be made to the combination of each component and each process, and it will be understood by those skilled in the art that it is within the scope of the present invention.

  For example, in the first to third embodiments described above, at least some or all of the functional components of the first to third ICs 38, 48, and 54 are physical components (for example, electric circuits, Element, device, etc.).

  In the first to third embodiments described above, the generated power source (for example, the first solar cell module 1a and the first wind power generator 10a) supplied between the power reception point R and the second power conditioner 4 is There may be one as shown in FIGS. 1, 3 and 4, or a plurality. Further, the generated power source (for example, the second solar cell module 1b and the second wind power generator 10b) supplied between the bidirectional inverter 42 and the bidirectional DC / DC converter 44 is also 1 as shown in FIGS. There may be one or more.

  In the first to third embodiments described above, the first power conditioner 3, the second power conditioner 4, and the controller 5 are individually provided. However, the application range of the present invention is not limited to this example. . At least a part of the components of the controller 5 may be included in the second power conditioner 4. For example, the power storage monitoring unit 541 and the second conversion control unit 542 of the controller 5 may be included in functional components of the second power conditioner 4 or the second IC 48. Further, at least a part or all of the components of the first power conditioner 3 may be included in the second power conditioner 4.

  According to the first to third embodiments described above, the power conditioner 4 is provided between the first power generators 1 a and 10 a and the commercial power system E, the second power generator 1 b and the power storage device 2. Power generated by the first power generators 1a and 10a connected to the transmission path P between the bidirectional power conversion section 42 and the transmission path P between the bidirectional power conversion section 42 and the commercial power system E A power determination unit 47 that determines whether or not the power consumption of the load L is equal to or greater than the power consumption of the load L; A conversion control unit 482 that sets the power conversion direction of the bidirectional power conversion unit 42 in the forward conversion direction a in which power is converted from the P side to the power storage device 2 side (first configuration).

  According to the first configuration, when the generated power of the first power generation devices 1a and 10a is equal to or higher than the power consumption of the power load L, the power consumption can be sufficiently covered by the generated power of the first power generation devices 1a and 10a. Therefore, surplus power can be sold to the commercial power system E. In this case, the power conditioner 4 gives priority to supplying the electric power generated by the first power generation devices 1a and 10a to the power storage device 2 and storing it, rather than selling power to the commercial power system E. Therefore, power sales to the commercial power system E can be suppressed. Furthermore, since the electric power is converted in the forward conversion direction a by the bidirectional power conversion unit 42, the electric power stored in the power storage device 2 is not sold to the commercial power system E. Therefore, the power conditioner 4 can suppress the use of the commercial power system E and use the generated power without causing the discharge power from the power storage device 2 to flow backward to the commercial power system E.

  The power conditioner 4 of the first to third embodiments further includes a power detection unit 47 that detects a power value W transmitted between the transmission path P and the commercial power system E, and the conversion control unit 482 includes a power determination unit. When the unit 47 determines that the power generated by the first power generators 1a and 10a is greater than or equal to the power consumption, the bidirectional power converter 42 performs forward conversion so that the power value W becomes the first target value W1. It is good also as a structure (2nd structure) which sets the electric power converted into the direction a according to the electric power value W. FIG.

  According to the second configuration, the bidirectional power conversion unit 42 can forward-convert power corresponding to the surplus power value W sold from the transmission path P to the commercial power system E. For example, the power converted by the bidirectional power converter 42 can be set lower as the power value W becomes smaller, and the power value W can be stabilized.

  In the power conditioner 4 of the first to third embodiments, the conversion control unit 482 stores the power when the power determination unit 47 does not determine that the generated power of the first power generation devices 1a and 10a is greater than or equal to the power consumption. A configuration (third configuration) may be employed in which the power conversion direction of the bidirectional power conversion unit 42 is set in the reverse conversion direction b in which power is converted from the device 2 side to the transmission path P side.

  According to the third configuration, when the first power generation devices 1a and 10a are less than the power consumption, the power generation power of the first power generation devices 1a and 10a is insufficient with respect to the power consumption. In this case, the power conditioner 4 can convert the discharge power of the power storage device 2 to the transmission path P side by the bidirectional power conversion unit 42 in order to compensate at least a part of the insufficient power. Therefore, power purchase from the commercial power system E can be suppressed. Therefore, the power conditioner 4 can use the generated power of the first power generators 1a and 10a while suppressing the use of the commercial power system E.

  The power conditioner 4 of the first to third embodiments further includes a storage / discharge power conversion unit 44 provided between the power storage device 2 and the bidirectional power conversion unit 42, and the power determination unit 47 has a bidirectional function. When the power conversion direction of the power conversion unit 42 is set to the reverse conversion direction b, the total power of the generated power of the first power generators 1a and 10a and the generated power of the second power generator 1b is greater than or equal to the power consumption. It is further determined whether or not the power conversion direction of the storage / discharge power conversion unit 44 is determined from the bidirectional power conversion unit 42 side when the power determination unit 47 determines that the total power is greater than or equal to the power consumption. Power is set from the power storage device 2 side to the bidirectional power conversion unit 42 when the power determination unit 47 does not determine that the total power is greater than or equal to the power consumption. Set in second direction B to convert It may be configured that (fourth configuration).

  According to the fourth configuration, when the generated power is greater than or equal to the consumed power, the power value W transmitted from the first power generators 1a and 10a to the commercial power system E becomes the second target value W2. The stored / discharge power conversion unit 44 can store the power stored in the power storage device 2 by converting the forward-converted power by the bidirectional power conversion unit 42. The generated power of the first solar cell modules 1a and 10a is less than the power consumption of the power load L, and the total power of the generated power of the first and second solar cell modules 1a, 10a and 1b is the consumption of the power load L. When the electric power is equal to or higher than the electric power, at least a part of the generated electric power of the second solar cell module 1b can be converted and stored in the storage battery 2 so that the electric power value W becomes the first target value. Therefore, it is possible to preferentially store the power generated in the second solar cell module 1 b in the storage battery 2 and suppress unnecessary fluctuations in the power conversion amount in the bidirectional DC / DC converter 44.

  In the power conditioner 4 of the first to third embodiments, when the power determination unit 47 determines that the total power is equal to or higher than the power consumption, the power value W becomes the second target value W2. The storage / discharge power conversion unit 44 may have a configuration (fifth configuration) in which the power converted in the first direction A is set according to the power value W.

  According to the fifth configuration, the power conversion amount of the storage / discharge power conversion unit 44 can be set according to the power value W sold from the transmission path P to the commercial power system E. If it carries out like this, it will become possible to preferentially accumulate | store in the storage battery 2, giving priority to the electric power generated by the 2nd solar cell module 1b, and to suppress the fluctuation | variation of the unnecessary power conversion amount in the storage / discharge power conversion part 44.

  The power control method according to the first to third embodiments includes a bidirectional power conversion unit provided between the first power generators 1a and 10a and the commercial power system E and the second power generators 1b and 10b and the power storage device 2. It is determined whether or not the generated power of the first power generators 1a and 10a connected to the transmission path P between the power line 42 and the commercial power system E is greater than or equal to the power consumption of the power load L connected to the transmission path P. The forward conversion direction a in which power is converted from the transmission path P side to the power storage device 2 side when it is determined that the generated power of the first power generation device 1a, 10a is greater than or equal to the power consumption. And a step of setting the power conversion direction of the bidirectional power converter 42 (sixth configuration).

  According to the sixth configuration, when the generated power of the first power generation devices 1a and 10a is equal to or higher than the power consumption of the power load L, the power consumption can be sufficiently covered by the generated power of the first power generation devices 1a and 10a. Therefore, surplus power can be sold to the commercial power system E. In this case, the power conditioner 4 gives priority to supplying the electric power generated by the first power generation devices 1a and 10a to the power storage device 2 and storing it, rather than selling power to the commercial power system E. Therefore, power sales to the commercial power system E can be suppressed. Furthermore, since the electric power is converted in the forward conversion direction a by the bidirectional power conversion unit 42, the electric power stored in the power storage device 2 is not sold to the commercial power system E. Therefore, the power conditioner 4 can use the generated power while suppressing the use of the commercial power system E without causing the discharge power from the power storage device 2 to flow backward to the commercial power system E.

DESCRIPTION OF SYMBOLS 100 Solar power generation system 100a Wind power generation system 1, 1a, 1b Solar cell module 10, 10a, 10b Wind power generator 2 Storage battery 3 1st power conditioner 31 DC / DC converter 31a AC / DC converter 32 Inverter 33 Capacitor 35 1st Communication unit 36 First memory 38 First IC
BL1 First bus line 4 Second power conditioner 41 DC / DC converter 41a AC / DC converter 42 Bidirectional inverter (bidirectional power converter)
43 Capacitor 44 Bidirectional DC / DC converter (storage / discharge power converter)
45 Second communication unit 46 Second memory 47 Energy meter (power detection unit, power determination unit, power transmission direction detection unit)
471 Electricity purchase meter 472 Electricity sale meter 48 Second IC
481 Power comparison unit 482 First conversion control unit (part of conversion control unit)
BL2 Second bus line 5 Controller 51 Input unit 52 Third communication unit 53 Third memory 54 Third IC
541 Charge amount monitoring unit 542 Second conversion control unit (part of conversion control unit)
R Power receiving point P Transmission path E Commercial power system L Power load

Claims (4)

A bidirectional power converter provided between the first power generator and the commercial power system and the second power generator and the power storage device;
It is determined whether or not the generated power of the first power generator connected to the transmission path between the bidirectional power converter and the commercial power system is greater than or equal to the power consumption of the power load connected to the transmission path A power determination unit to perform,
When the power determination unit determines that the generated power of the first power generation device is equal to or greater than the power consumption, the bidirectional power in a forward conversion direction in which power is converted from the transmission path side to the power storage device side. A conversion control unit for setting the power conversion direction of the conversion unit;
A storage / discharge power conversion unit provided between the power storage device and the bidirectional power conversion unit;
Equipped with a,
The conversion control unit is a reverse conversion direction in which power is converted from the power storage device side to the transmission path side when the power determination unit does not determine that the generated power of the first power generation device is greater than or equal to the power consumption. To set the power conversion direction of the bidirectional power conversion unit,
The power determination unit, when the power conversion direction of the bidirectional power conversion unit is set to the reverse conversion direction, the sum of the generated power of the first power generation device and the generated power of the second power generation device Further determining whether the power is greater than or equal to the power consumption,
The power conversion direction of the storage / discharge power conversion unit is:
When the power determination unit determines that the total power is greater than or equal to the power consumption, it is set in a first direction for power conversion from the bidirectional power conversion unit side to the power storage device side,
A power conditioner that is set in a second direction for performing power conversion from the power storage device side to the bidirectional power conversion unit side when the power determination unit does not determine that the total power is greater than or equal to the power consumption . A power detector for detecting a power value transmitted between the transmission path and the commercial power system;
When the power determination unit determines that the generated power of the first power generation device is greater than or equal to the power consumption, the conversion control unit is configured to output the bidirectional power so that the power value becomes a first target value. The power conditioner of Claim 1 which sets the electric power converted by the conversion part in the forward conversion direction according to the said electric power value. When the power determination unit determines that the total power is greater than or equal to the power consumption, the storage / discharge power conversion unit converts the power value into the first direction so that the power value becomes a second target value. The power conditioner according to claim 2 , wherein the power to be set is set according to the power value. Generated power of the first power generation device connected to a transmission path between the bidirectional power conversion unit provided between the first power generation device and the commercial power system and the second power generation device and the power storage device and the commercial power system. a step but whether or not the power consumption or power load connected to said transmission path, to be determined,
When it is determined in the determining step that the generated power of the first power generation device is greater than or equal to the power consumption, the power conversion direction of the bidirectional power conversion unit is changed from the transmission path side to the power storage device side. A step set in a forward conversion direction in which power is converted;
If it is not determined that the generated power of the first power generator is greater than or equal to the power consumption in the determined step, the power conversion direction of the bidirectional power converter is power from the power storage device side to the transmission path side. A step set in the reverse transformation direction in which
When the power conversion direction of the bidirectional power converter is set to the reverse conversion direction, the total power of the generated power of the first power generator and the generated power of the second power generator is equal to or greater than the power consumption. A step of further determining whether or not
The power conversion direction of the storage / discharge power conversion unit provided between the power storage device and the bidirectional power conversion unit when the total power is determined to be greater than or equal to the power consumption in the further determining step Is set in a first direction for power conversion from the bidirectional power conversion unit side to the power storage device side;
When the total power is not determined to be greater than or equal to the power consumption in the further determined step, the power conversion direction of the storage / discharge power conversion unit is the power from the power storage device side to the bidirectional power conversion unit side. A step set in a second direction to convert;
A power control method comprising:

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