JP2016082601A - Power conditioner, and power control method and power control system for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize a generated power outputted from a power generator to a transmission line in a case where a voltage value at the transmission line between a commercial power system and itself rises.SOLUTION: A power control system comprises: a first power generator that generates a first generated power; a second power generator that generates a second generated power; a power storage device; first and second power conditioners; and voltage detection means. The first power conditioner is connected with the first power generator and the power storage device, and connected with the commercial power system via the transmission line. The second power conditioner is connected with the second power generator and the transmission line, and outputs to the transmission line an output power obtained by converting the second generated power. The voltage detection means detects a voltage at the transmission line. The first power conditioner, in a case where a value of the voltage at the transmission line is larger than a predetermined value, performs power storage control so that the first generated power and the output power can be stored in the power storage device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power conditioner, a power control method thereof, and a power control system.

  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.

  On the other hand, in a solar power system, a storage battery that stores power generated by solar power may be installed. This storage battery is used, for example, as a standby power source when a power failure occurs at night when solar power generation is not possible, or as an auxiliary power source when the power consumption of the load power system temporarily protrudes and becomes large.

  By the way, when the generated power of the power generation system increases, the voltage of the transmission line between the power generation system and the commercial power system may increase. In order to suppress this increase in voltage, for example, for a rated voltage of 100 V, it is obliged that the average value of the voltage in a predetermined period (30 minutes) does not exceed the legal numerical range (for example, 101 ± 6 V). ing. Therefore, the power conditioner of the power generation system has a function of managing and adjusting the upper limit value of the voltage as disclosed in Patent Document 1, for example.

  Patent Document 1 discloses a power generator including an inverter that is connected between a solar cell and a storage battery and an AC power source and controls electric power output from the solar cell side to the AC power source side. In this power generator, when the voltage of the AC power source exceeds the upper limit voltage, at least a part of the generated power of the solar battery is stored in the storage battery. Further, when the voltage of the AC power supply is lower than the lower limit voltage, the discharge power of the storage battery is output to the AC power supply side.

  Here, with the widespread use of power generation systems, the number of cases where a new power generation device is added to a power generation system including a power storage device is increasing. In this case, the new power generator outputs the generated power to the transmission line between the existing power conditioner and the commercial power system.

Japanese Patent No. 4566658

  However, in the above power generation system, when the voltage value of the transmission line between the power generation system and the commercial power system exceeds the legal upper limit value, the output of the generated power of the new power generation device to the transmission line is reduced and reduced. Therefore, the power generated by the new power generator is not used effectively. In addition, the power generated by the new power generator cannot be used at all when the output to the transmission line is set to zero.

  With respect to such a problem, Patent Document 1 does not assume a power generation system in which a new power generation device is connected between an existing power conditioner and a commercial power system. That is, Patent Document 1 does not consider the above-described problems.

  The present invention has been made in view of such a situation, and when the voltage value of the transmission line between the commercial power system rises, the generated power output from the power generation device to the transmission line is effectively used. It is an object of the present invention to provide a power conditioner that can be used, a power control method thereof, and a power control system.

  In order to achieve the above object, a power conditioner according to an aspect of the present invention is a power conditioner that is connected to a first power generation device and a power storage device and connected to a commercial power system via a transmission line. When the voltage value of the transmission line detected by the voltage detection means is larger than a predetermined value, the first generated power generated by the first power generator and the second generated by the second power generator A configuration (first configuration) is provided that includes a control unit that performs power storage control that enables the power storage device to store the output power of another power conditioner that converts the generated power and outputs the power to the transmission line.

  In the first configuration, the predetermined value is compared with the value of the voltage of the transmission line by another power conditioner, and when the value of the voltage is larger, It is good also as a structure (2nd structure) set to less than the threshold value in which the power conversion amount of 2 generated electric power is reduced.

  Alternatively, in the first configuration, when the communication unit further includes a communication unit that communicates with another power conditioner, and the value of the voltage of the transmission line is larger than a predetermined value, the communication unit is connected to the other power conditioner. Thus, a configuration (third configuration) may be employed in which conversion control information used for determining whether or not to reduce the power conversion amount of the second generated power is transmitted to another power conditioner.

  In order to achieve the above object, a power control method according to an aspect of the present invention is a power conditioner that is connected to a first power generation device and a power storage device and connected to a commercial power system via a transmission line. The first power generation generated by the first power generator and the second power generator when the voltage value of the transmission line detected by the voltage detection means is greater than a predetermined value. A configuration (fourth configuration) including a step of performing power storage control that enables the power storage device to store the output power of another power conditioner that converts the second generated power generated by the power converter and outputs the power to the transmission line. Is done.

  In order to achieve the above object, a power control system according to an aspect of the present invention includes a first power generation device that outputs first generated power, a second power generation device that outputs second generated power, and a power storage device. And a first power conditioner connected to the commercial power system via a transmission line, a second power generation device and a transmission line, and connected to the first power generation device and the power storage device. A second power conditioner for outputting the power converted to the transmission line; and a voltage detection means for detecting the voltage of the transmission line. The first power conditioner is a transmission line detected by the voltage detection means. When the voltage value is larger than a predetermined value, the power storage control is performed to allow the first generated power and the output power to be stored in the power storage device (fifth configuration).

  ADVANTAGE OF THE INVENTION According to this invention, when the voltage value of the transmission line between commercial power systems rises, the generated electric power output to a transmission line from a generator can be utilized effectively.

It is a block diagram which shows the structural example of the solar energy power generation system which concerns on 1st Embodiment. It is a flowchart for demonstrating an example of the electric power control method of the 1st power conditioner in 1st Embodiment. It is a flowchart for demonstrating an example of the electric power control method of the 2nd power conditioner in 1st Embodiment. It is a block diagram which shows the structural example of the solar energy power generation system which concerns on 2nd Embodiment. It is a flowchart for demonstrating an example of the electric power control method of the 1st power condition in 2nd Embodiment. It is a flowchart for demonstrating an example of the electric power control method of the 2nd power conditioner in 2nd Embodiment. It is a block diagram which shows the structural example of the wind power generation system which concerns on 3rd Embodiment.

  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 photovoltaic power generation system 100 according to the first embodiment. The solar power generation system 100 is a power generation system having the solar cell module 1 and the storage battery 2, and is a distributed power source that supplies power by a power generation method that converts sunlight into electric power. The solar power generation system 100 is connected to the commercial power system E via the transmission line P and the power receiving point R. In addition, a power load L is also connected to the transmission line P. The power load L is, for example, a domestic appliance or a factory equipment, and consumes power supplied to the transmission line P in the solar power generation system 100.

  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 first solar cell module 1 a generates the first generated power input to the first power conditioner 3, and the second solar cell module 1 b generates the second generated power input to the second power conditioner 4. In addition, the 1st solar cell module 1a is an example of the 1st electric power generating apparatus of this invention, and the 2nd solar cell module 1b is an example of the 2nd electric power generating apparatus of this invention.

  The storage battery 2 is a power storage device including a secondary battery that can repeatedly store and discharge. The storage battery 2 can store DC power using the DC power supplied from the first power conditioner 3, and can discharge DC power corresponding to the stored power (that is, the storage amount wa). . In the following, the power supplied to the storage battery 2 is referred to as stored power, and the 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 1st power conditioner 3 is a 1st electric power control apparatus which controls the electric power generation of the 1st solar cell module 1a. The first power conditioner 3 is connected to the first solar cell module 1 a and the storage battery 2, and is connected to the commercial power system E via the transmission line P.

  The first power conditioner 3 normally controls the operating voltage (operating point) of the first solar cell module 1a so that the generated power becomes maximum, for example, by MPPT (Maximum Power Point Tracking) control. However, when the first power conditioner 3 needs to limit the power generation of the first generated power in the first solar cell module 1a, the value obtained by shifting the operating voltage of the first solar cell module 1a from the maximum output operating voltage. To adjust the first generated power. In addition, the first power conditioner 3 also functions as a storage / discharge control device for the storage battery 2, and supplies stored power to the storage battery 2 or receives supply of discharge power from the storage battery 2.

  The first power conditioner 3 includes a DC / DC converter 31, a bidirectional inverter 32, a capacitor 33, a bidirectional DC / DC converter 34, a communication unit 35, a memory 36, a watt hour meter 37, a voltage It has a total of 38 and IC39. The DC / DC converter 31, the bidirectional inverter 32, and the bidirectional DC / DC converter 34 are connected to each other via a bus line BL. Further, the first power conditioner 3 is provided with an output terminal 3 a connected to the transmission line P.

  The DC / DC converter 31 is a direct current converter connected to the first solar cell module 1a. The DC / DC converter 31 is provided between the first solar cell module 1a and the bus line BL, converts the generated power of the first solar cell module 1a into DC power having a predetermined voltage value, and outputs it to the bus line BL. Further, the DC / DC converter 31 prevents a reverse current from flowing through the first solar cell module 1a.

  The bidirectional inverter 32 is a bidirectional power converter provided between the transmission line P and the bus line BL. One end of the bidirectional inverter 32 is connected to the bus line BL, and the other end is connected to the power receiving point R via the transmission line P. Hereinafter, when the bidirectional inverter 32 performs AC / DC conversion on the power input from the transmission line P and outputs it to the bus line BL 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 transmission line P side to the bus line BL side. In addition, when the bidirectional inverter 32 performs DC / AC conversion on the power input from the bus line BL and outputs it to the transmission line P is called reverse conversion, and this power conversion direction is called reverse conversion direction b. That is, the reverse conversion direction b is a power conversion direction in which power is converted from the bus line BL side to the transmission line P side.

  When the bidirectional inverter 32 is set in the forward conversion direction a, the alternating current power input from the transmission line P is forward converted to direct current power and output to the bus line BL. Further, when the bidirectional inverter 32 is set in the reverse conversion direction b, the direct current power input from the bus line BL is reversely converted into power of an AC frequency corresponding to the power receiving point R (and the commercial power system E). And output to the transmission line P. As will be described later, these operations are controlled by the IC 39.

  The capacitor 33 is connected to the bus line BL, and removes or reduces fluctuations in the bus voltage value of the power flowing through the bus line BL.

  The bidirectional DC / DC converter 34 is a storage / discharge power conversion unit provided between the bus line BL and the storage battery 2. One end of the bidirectional DC / DC converter 34 is connected to the storage battery 2, and the other end is connected to the bus line BL. In the following description, the bidirectional DC / DC converter 34 DC / DC converts the power input from the bus line BL and outputs it to the storage battery 2 is referred to as storage conversion, and this power conversion direction is referred to as storage direction A. . That is, the storage direction A is a power conversion direction in which power is converted from the bus line BL side to the storage battery 2 side. The bidirectional DC / DC converter 34 DC / DC converts the power input from the storage battery 2 and outputs it to the bus line BL is called discharge conversion, and this power conversion direction is called the discharge direction B. That is, the discharge direction B is a power conversion direction in which power is converted from the storage battery 2 side to the bus line BL side.

  When the bidirectional DC / DC converter 34 is set in the storage direction A, the direct-current power flowing through the bus line BL is converted into direct-current stored power suitable for the storage battery 2 and output to the storage battery 2. Moreover, when the bidirectional DC / DC converter 34 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 bus line BL. As will be described later, these operations are controlled by the controller 5.

  The communication unit 35 is a communication interface that performs wireless communication or wired communication with the controller 5. The communication unit 35 transmits, for example, output results of a watt hour meter 37 and a voltmeter 38 described later, a comparison result of a voltage comparison unit 391 described later, control information, and the like to the controller 5.

  The memory 36 is a non-volatile storage medium that holds stored information non-temporarily without supplying power. The memory 36 stores control information and programs used by each functional element (particularly IC 39) of the first power conditioner 3.

  The watt-hour meter 37 is a power detection unit that detects a power value W transmitted between the photovoltaic power generation system 100 and the commercial power system E via the transmission line P and the power receiving point R. Detects the power that is sent or sold. The detection result of the watt-hour meter 37 is output to the IC 39. The watt hour meter 37 may be built in the first power conditioner 3 as shown in FIG. 1 or may be externally attached to the first power conditioner 3.

  The watt-hour meter 37 includes a power sales meter 371 and a power purchase meter 372. Each of the electric power sales meter 371 and the purchased electric power meter 372 is an electric energy measuring device with a reverse rotation prevention function that detects electric power transmitted in one direction. Each of the electricity sales meter 371 and the electricity purchase meter 372 is not particularly limited, and for example, an energy meter such as an induction energy meter, a reactive energy meter, and an electronic energy meter can be used. Further, the power sale meter 371 and the purchased power meter 372 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 solar power generation system 100 to the commercial power grid E at the power receiving point R, the power sale meter 371 detects that the solar power generation system 100 is selling power to the commercial power grid E. Hereinafter, a 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. The electric power sales meter 371 further detects the electric power value W sold from the photovoltaic power generation system 100 to the commercial power system E as the electric power sales quantity, and integrates the electric power sales quantity. Then, the electricity sales meter 371 outputs these results to the IC 39.

  When power is transmitted from the commercial power system E to the solar power generation system 100 at the power receiving point R, the purchased power meter 372 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. The power purchase meter 372 further detects the power value purchased from the commercial power grid E as the power purchase amount, and integrates the power purchase amount. The power purchase meter 372 outputs these results to the IC 39.

  Note that the watt-hour meter 37 has a power value when the power sale meter 371 detects a power value W> 0, or there is no power transmission via the power receiving point R and the power sale meter 371 and the purchased power meter 372 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 372 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 37 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 voltmeter 38 is a first voltage detection unit that detects a voltage at the output terminal 3 a of the first power conditioner 3. The detection result of the voltmeter 38 is output to the IC 39. The voltmeter 38 may be incorporated in the first power conditioner 3 as shown in FIG. 1 or may be externally attached to the first power conditioner 3. Moreover, since the voltage detected by the voltmeter 38 indicates the voltage Vp of the power transmitted through the transmission line P, the voltage Vp will be described below.

  The IC 39 is a control unit that controls each component of the first power conditioner 3 using information, a program, and the like stored in the memory 36. In addition, when the value of the voltage Vp of the transmission line P detected by the voltmeter 38 is larger than a predetermined value, the IC 39 has a first generated power generated by the first solar cell module 1a and a second power Power storage control is performed so that the output power of the conditioner 4 can be stored in the storage battery 2.

  The IC 39 includes a voltage comparison unit 391 and a conversion control unit 392 as functional components.

  The voltage comparison unit 391 compares the value of the voltage Vp detected by the voltmeter 38 with a predetermined value. The predetermined value includes, for example, the upper limit set value VH of the voltage range to be maintained in the transmission line P. If the rated voltage of the power supplied from the solar power system 100 to the power load L is 100 [V], the upper limit set value VH is set to 107 [V], for example.

  The conversion control unit 392 controls the bidirectional inverter 32 based on the detection results of the watt-hour meter 37 and the voltmeter 38, the comparison result of the voltage comparison unit 391, and in particular, controls the power conversion direction and the power conversion amount. To do.

  Next, the second power conditioner 4 will be described. The 2nd power conditioner 4 is a 2nd electric power control apparatus which controls the electric power generation of the 2nd solar cell module 1b. The second power conditioner 4 is connected to the second solar cell module 1b and the transmission line P.

  The second power conditioner 4 normally controls the operating voltage (operating point) of the second solar cell module 1b so that the generated power becomes maximum, for example, by MPPT control. However, the second power conditioner 4 is a value obtained by shifting the operating voltage of the second solar cell module 1b from the maximum output operating voltage when it is necessary to limit the power generation of the second generated power in the second solar cell module 1b. To adjust the second generated power. Moreover, the 2nd power conditioner 4 outputs the output electric power which carried out power conversion of the 2nd generated electric power of the 2nd solar cell module 1b to the transmission line P. FIG.

  As shown in FIG. 1, the second power conditioner 4 includes a DC / DC converter 41, an inverter 42, a capacitor 43, a memory 46, a voltmeter 48, and an IC 49. In addition, the second power conditioner 4 may further include a communication interface (for example, a communication unit 45 in FIG. 4 described later) that performs wireless communication or wired communication with the first power conditioner 3 and the controller 5. Further, the second power conditioner 4 is provided with an output terminal 4 a connected to the transmission line P.

  The DC / DC converter 41 is a direct current conversion unit connected to the second solar cell module 1b, converts the generated power into direct current power having a predetermined voltage value, and outputs the direct current power to the inverter 42. Further, the DC / DC converter 41 prevents a reverse current from flowing through the second solar cell module 1b.

  The inverter 42 is connected to the transmission line P between the power receiving point R and the bidirectional inverter 32, and converts DC power input from the DC / DC converter 41 into AC frequency power corresponding to the commercial power system E. To the transmission line P.

  The capacitor 43 is connected to the bus line between the DC / DC converter 41 and the inverter 42, and removes or reduces the fluctuation of the bus voltage value of the power flowing through the bus line.

  The memory 46 is a non-volatile storage medium that holds stored information in a non-temporary manner without supplying power. The memory 46 stores control information, a program, and the like used by each functional element (particularly, the IC 49) of the second power conditioner 4.

  The voltmeter 48 is a second voltage detection unit that detects a voltage at the output terminal 4 a of the second power conditioner 4. The detection result of the voltmeter 48 is output to the IC 49. The voltmeter 48 may be incorporated in the second power conditioner 4 as shown in FIG. 1 or may be externally attached to the second power conditioner 4. Moreover, since the voltage detected by the voltmeter 48 indicates the voltage Vp of the power transmitted through the transmission line P, the voltage Vp will be described below.

  The IC 49 is a control unit that controls each component of the second power conditioner 4 using information and programs stored in the memory 46. The IC 49 includes a voltage comparison unit 491 and a conversion control unit 492 as functional components.

  The voltage comparison unit 491 compares the value of the voltage Vp detected by the voltmeter 48 with a predetermined value. The predetermined threshold includes, for example, an upper limit control value Vu. The upper limit control value Vu is a threshold value for determining whether the second power conditioner 4 reduces the power conversion amount of the second generated power. The upper limit control value Vu is set to a higher value (for example, 110 [V]) than the upper limit set value VH of the first power conditioner 3. In this way, power control (that is, voltage Vp increase suppression control) is performed in the first power conditioner 3 without performing communication between the first power conditioner 3 and the second power conditioner 4. After that, power control by the second power conditioner 4 is performed. Therefore, for example, an existing power conditioner can be used as the second power conditioner 4 without making a special change to the specification.

  The conversion control unit 492 controls the inverter 42 based on the detection result of the voltmeter 48, the comparison result of the voltage comparison unit 491, etc., and in particular controls the amount of power conversion.

  Next, the controller 5 is an external control device that controls the storage battery 2 and the bidirectional DC / DC converter 34 and receives user input. The controller 5 includes an input unit 51, a controller communication unit 52, a controller memory 53, and a controller IC 54.

  The input unit 51 receives a user input and outputs an input signal corresponding to the user input to the controller IC 54.

  The controller communication unit 52 is a communication interface that performs wireless communication or wired communication with the communication unit 35 of the first power conditioner 3. For example, the controller communication unit 52 receives the determination result of the watt hour meter 37 and the comparison result of the voltage comparison unit 391 from the communication unit 35.

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

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

  The storage amount monitoring unit 541 monitors the storage amount wa of the storage battery 2. The power storage amount monitoring unit 531 monitors, for example, the power storage amount wa, and determines whether or not the power storage amount wa has reached the power storage capacity wc.

  The storage / discharge control unit 532 controls the bidirectional DC / DC converter 34. In particular, the storage / discharge control unit 532 determines the power conversion direction of the bidirectional DC / DC converter 34 based on the determination result of the watt-hour meter 37, the comparison result of the voltage comparison unit 391, and the monitoring result of the storage amount monitoring unit 531. And control the power conversion operation.

  Further, when the monitoring result of the storage amount monitoring unit 531 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 storage / discharge control unit 532 controls the bidirectional DC / DC converter 34 so as not to convert the electric power in the storage direction A. For example, the storage / discharge control unit 532 sets the power conversion direction of the bidirectional DC / DC converter 34 to the discharge direction B. Alternatively, the storage / discharge control unit 532 sets the power conversion amount in the bidirectional DC / DC converter 34 to 0, and stops the power conversion operation in the bidirectional DC / DC converter 34. 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 failure | damage etc. can also be prevented.

  Next, a power control process for controlling the increase in the voltage Vp of the transmission path P will be described. The power control process described below is started, for example, when power is transmitted in the power selling direction at the power receiving point R during power generation of the solar cell module 1. When power generation is stopped or power is transmitted in the power purchase direction at the power receiving point R during power generation of the solar cell module 1, the process ends.

  First, a power control process for suppressing a voltage increase in the transmission path P by the first power conditioner 3 will be described. FIG. 2 is a flowchart for explaining an example of the power control method of the first power conditioner 3 in the first embodiment.

  First, the value of the voltage Vp is detected by the voltmeter 38, and it is determined whether or not it is larger than the upper limit set value VH (step S101). If it is not determined that the value of voltage Vp is greater than upper limit set value VH (NO in step S101), the process proceeds to A and returns to step S101.

  On the other hand, when it is determined that the value of voltage Vp is greater than upper limit set value VH (YES in step S101), the power conversion direction of bidirectional DC / DC converter 34 is set to storage direction A (step S102). Then, it is determined whether or not the power conversion direction of the bidirectional inverter 32 is set to the reverse conversion direction b (step S103). If it is not determined that the reverse conversion direction b is set (NO in step S103), the process proceeds to step S110 described later.

  When it is determined that the reverse conversion direction b is set (YES in step S103), the value of the voltage Vp is detected and it is determined whether or not it is larger than the upper limit set value VH (step S104). If it is not determined that the value of voltage Vp is greater than upper limit set value VH (NO in step S104), the process proceeds to A and returns to step S101. On the other hand, when it is determined that the value of the voltage Vp is larger than the upper limit set value VH (YES in step S104), it is determined whether or not the reverse conversion amount of the bidirectional inverter 32 is 0 (step S105).

  When it is not determined that the reverse conversion amount is 0 (NO in step S105), the bidirectional inverter 32 is controlled so that the reverse conversion amount is reduced (step S106). At this time, normally, a part of the first generated power of the first solar cell module 1 a is stored in the storage battery 2. However, when the power conversion amount of the bidirectional DC / DC converter 34 reaches the maximum value, the first generated power of the first solar cell module 1a is reduced according to the reduction of the reverse conversion amount in the bidirectional inverter 32. In order to reduce, the operating voltage of the first solar cell module 1a is set to a value deviated from the maximum output operating voltage. Then, the process returns to step S104.

  When it is determined that the reverse conversion amount is 0 (YES in step S105), it is determined whether or not the power conversion amount of the bidirectional DC / DC converter 34 has reached the maximum value (step S107). When it is determined that the power conversion amount of bidirectional DC / DC converter 34 has reached the maximum value (YES in step S107), the process proceeds to A and returns to step S101.

  When it is not determined that the power conversion amount of the bidirectional DC / DC converter 34 has reached the maximum value (NO in step S107), the power conversion direction of the bidirectional inverter 32 is set to the forward conversion direction a (step S108). . Then, the value of the voltage Vp is detected and it is determined whether or not it is larger than the upper limit set value VH (step S109). If it is not determined that the value of voltage Vp is greater than upper limit set value VH (NO in step S109), the process proceeds to A and returns to step S101.

  On the other hand, when it is determined that the value of the voltage Vp is larger than the upper limit set value VH (YES in step S109), it is determined whether or not the forward conversion amount of the bidirectional inverter 32 is maximum (step S110). Here, for example, it is determined whether or not the power conversion amount that the bidirectional inverter 32 converts in the forward conversion direction a is the maximum set value. If it is determined that the forward conversion amount is the maximum (YES in step S110), the process returns to step S109. On the other hand, when it is not determined that the forward conversion amount is the maximum (NO in step S110), the bidirectional inverter 32 is controlled so that the forward conversion amount increases (step S112). Then, the process returns to step S109.

  Next, a power control process for suppressing a voltage increase in the transmission path P by the second power conditioner 4 will be described. FIG. 3 is a flowchart for explaining an example of the power control method of the second power conditioner 4 in the first embodiment.

  First, the value of the voltage Vp at the output terminal 4a is detected by the voltmeter 48, and it is determined whether or not it is larger than the upper limit control value Vu (step S121). If it is not determined that the value of voltage Vp is greater than upper limit control value Vu (NO in step S121), the process returns to step S121.

  On the other hand, when it is determined that the value of the voltage Vp is larger than the upper limit control value Vu (YES in step S121), it is determined whether or not the power conversion amount of the inverter 42 is 0 (step S122). If it is determined that the power conversion amount is 0 (YES in step S122), the process returns to step S121.

  When it is not determined that the power conversion amount is 0 (NO in step S122), the inverter 42 is controlled so that the power conversion amount is reduced (step S123). At this time, the operating voltage of the second solar cell module 1b deviates from the maximum output operating voltage in order to reduce the second generated power of the second solar cell module 1b in accordance with the reduction of the power conversion amount in the inverter 42. Set to a value. Then, the process returns to step S121.

Second Embodiment
Next, a second embodiment will be described. Hereinafter, a configuration different from the first embodiment will be described. Moreover, the same code | symbol is attached | subjected to the structure part similar to 1st Embodiment, and the description may be abbreviate | omitted.

  FIG. 4 is a block diagram illustrating a configuration example of the solar power generation system 100 according to the second embodiment. In the first power conditioner 3, the communication unit 35 performs wireless communication or wired communication with the second power conditioner 4 and the controller 5. The communication unit 35 transmits, for example, control information output from the conversion control unit 392 to the second power conditioner 4. Moreover, when the value of the voltage Vp of the transmission line P is larger than the upper limit set value VH, the communication unit 35 determines whether to reduce the power conversion amount of the second generated power in the second solar cell module 1b. The conversion control information to be used is transmitted to the second power conditioner 4.

  In the first power conditioner 3, the voltmeter 38 detects the voltage at the power receiving point R and outputs the detection result to the IC 39. Since the voltage detected by the voltmeter 38 indicates the value of the voltage Vp of the power transmitted through the transmission line P, the voltage Vp will be described below.

  As shown in FIG. 4, the second power conditioner 4 includes a DC / DC converter 41, an inverter 42, a capacitor 43, a communication unit 45, a memory 46, and an IC 49. The IC 49 includes a conversion control unit 492 as a functional component.

  The communication unit 45 is a communication interface that performs wireless communication or wired communication with the first power conditioner 3 and the controller 5. The communication unit 45 receives various control information such as conversion control information from the first power conditioner 3.

  The conversion control unit 492 controls the inverter 42 based on the control information transmitted from the first power conditioner 3, and particularly controls the power conversion amount based on the conversion control information.

  Next, a power control process for controlling the increase in the voltage Vp of the transmission path P will be described. This power control process is started, for example, when power is transmitted in the power selling direction at the power receiving point R during the power generation of the solar cell module 1. Moreover, it ends when power generation is stopped or power is transmitted in the power purchase direction at the power receiving point R during power generation of the solar cell module 1.

  First, the process which suppresses the voltage rise of the transmission path P by the 1st power conditioner 3 is demonstrated. FIG. 5 is a flowchart for explaining an example of the power control method of the first power conditioner 3 in the second embodiment. Note that steps S101 to S110 and S112 in FIG. 5 are the same as those in the first embodiment (see FIG. 2), and thus description thereof is omitted.

  When step S110 of FIG. 5 is NO (that is, when it is not determined that the forward conversion amount of the bidirectional inverter 32 is the maximum), the second power conditioner 4 is controlled to suppress the increase in the voltage Vp of the transmission path P. Therefore, conversion control information (for example, a maintenance command) indicating that the power conversion amount of the inverter 42 is not reduced is transmitted from the communication unit 35 to the second power conditioner 4 (step S211). Then, the bidirectional inverter 32 is controlled such that the forward conversion amount increases (step S112), and the process returns to step S109.

  On the other hand, when step S110 is YES, in order to cause the second power conditioner 4 to perform the increase suppression control of the voltage Vp of the transmission path P, conversion control information indicating that the power conversion amount of the inverter 42 is reduced (for example, a reduction command) ) Is transmitted from the communication unit 35 to the second power conditioner 4 (step S213). Then, the process returns to step S109.

  Next, the process which suppresses the voltage rise of the transmission path P by the 2nd power conditioner 4 is demonstrated. FIG. 6 is a flowchart for explaining an example of the power control method of the second power conditioner 4 in the second embodiment.

  First, it is determined whether or not the conversion control information received by the communication unit 45 indicates a reduction command for reducing the power conversion amount of the inverter 42 (step S221). If the conversion control information is not a reduction command (NO in step S221), the process returns to step S221. On the other hand, when the conversion control information is a reduction command (YES in step S221), subsequent steps S122 and S123 are performed. In addition, since these processes are the same as that of 1st Embodiment (refer FIG. 3), these description is abbreviate | omitted.

<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 may be abbreviate | omitted.

  Here, a wind power generation system 100a will be described as an example of a power generation system using renewable energy. The wind power generation system 100a is a distributed power source that supplies power by a power generation method using wind power.

  FIG. 7 is a block diagram illustrating a configuration example of the wind power generation system 100a. As shown in FIG. 7, 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 a bidirectional inverter 32, a capacitor 33, a bidirectional DC / DC converter 34, a communication unit 35, a memory 36, a watt hour meter 37, a voltmeter 38, and an IC 39, as well as an AC / AC. A DC converter 31a is provided. The second power conditioner 4 has an AC / DC converter 41a in addition to the inverter 42, the capacitor 43, the memory 46, the voltmeter 48, and the IC 49.

  The wind power generator 10 includes a first wind power generator 10a that generates first generated power and a second wind power generator 10b that generates second generated power. 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.

  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 ICs 39 and 49 and the controller IC 54 are physical components (for example, electric circuits, elements, devices, etc.). ).

  The first solar cell module 1a of the first and second embodiments described above and the first wind power generator 10a of the third embodiment may be one as shown in FIG. 1, FIG. 4, and FIG. There may be a plurality. Similarly, the second solar cell module 1b of the first and second embodiments described above and the second wind power generator 10b of the third embodiment are one as shown in FIG. 1, FIG. 4, and FIG. There may be more than one.

  Moreover, in the above-mentioned 1st-3rd embodiment, although the controller 5 is provided separately with the 1st power conditioner 3, the application range of this invention is not limited to this illustration. At least a part of the components of the controller 5 may be included in the first power conditioner 3. For example, the power storage monitoring unit 541 and the storage / discharge control unit 542 of the controller 5 may be included in functional components of the first power conditioner 3 or the IC 39.

  The power conditioner 3 according to the embodiment described above is a power conditioner 3 that is connected to the first power generation devices 1a and 10a and the power storage device 2 and connected to the commercial power system E via the transmission line P. When the value of the voltage Vp of the transmission line P detected by the voltage detection means 38 is larger than a predetermined value VH, the first generated power generated by the first power generators 1a and 10a and the second generated power A control unit 39 that performs power storage control that enables the power storage device 2 to store the output power of another power conditioner 4 that converts the second generated power generated by the devices 1b and 10b and outputs the power to the transmission line P. It is set as the structure (1st structure) provided.

  According to the first configuration, the first generated power generated by the first power generators 1a and 10a by the power storage control performed when the value of the voltage Vp of the transmission line P is larger than the predetermined value VH. The power storage device 2 can store the output power of the other power conditioner 4 output to the transmission line P. Therefore, when the value of the voltage Vp of the transmission line P between the commercial power system E and the power conditioner 3 increases, the first generated power of the first power generators 1a and 10a and the second power generators 1b and 10b The second generated power can be used effectively.

  In the power conditioner 3 having the first configuration, the predetermined value VH is compared with the value of the voltage Vp of the transmission line P in the other power conditioner 4, and the value of the voltage Vp is larger. In addition, a configuration (second configuration) may be employed in which the power conversion amount of the second generated power is reduced by the other power conditioner 4 to be less than the threshold value Vu.

  According to the second configuration, even if communication between the power conditioner 3 and the other power conditioner 4 is not performed, after the power control in the power conditioner 3 is performed, the other power conditioner 4 Power control is performed at. Therefore, for example, an existing power conditioner can be used as another power conditioner 4 without making any special changes to the specification.

  Alternatively, the power conditioner 3 having the first configuration further includes a communication unit 35 that communicates with the other power conditioner 4, and when the value of the voltage Vp of the transmission line P is larger than a predetermined value VH, The communication unit 35 is configured to transmit the conversion control information used for determining whether or not the power conversion amount of the second generated power is reduced in the other power conditioner 4 to the other power conditioner 4 (third Configuration).

  According to the third configuration, after power control is performed by the power conditioner 3 based on the conversion control information transmitted from the power conditioner 3 to the other power conditioner 4, the power control is performed on the other power conditioner 4. Can be done.

  In addition, the power control method of the power conditioner 3 according to the embodiment described above is connected to the first power generation devices 1a and 10a and the power storage device 2 and to the commercial power system E via the transmission line P. In the power control method of the power conditioner 3, when the value of the voltage Vp of the transmission line P detected by the voltage detection means 38 is larger than a predetermined value VH, the first power generators 1 a and 10 a generate power. The power storage device 2 can store the first generated power and the output power of the other power conditioner 4 that converts the second generated power generated by the second power generation devices 1b and 10b and outputs the power to the transmission line P. It is set as the structure (4th structure) provided with the step which performs the electrical storage control.

  According to the fourth configuration, the first generated power generated by the first power generators 1a and 10a by the power storage control performed when the value of the voltage Vp of the transmission line P is larger than the predetermined value VH. The power storage device 2 can store the output power of the other power conditioner 4 output to the transmission line P. Therefore, when the value of the voltage Vp of the transmission line P between the commercial power system E and the power conditioner 3 increases, the first generated power of the first power generators 1a and 10a and the second power generators 1b and 10b The second generated power can be used effectively.

  Further, according to the embodiment described above, the power control systems 100 and 100a include the first power generation devices 1a and 10a that output the first generated power and the second power generation devices 1b and 10b that output the second generated power. And the first power conditioner 3 connected to the commercial power system E through the transmission line P, and the second power generation device, connected to the power storage device 2, the first power generation devices 1a, 10a, and the power storage device 2. A second power conditioner 4 connected to 1b, 10b and the transmission line P and outputting the output power obtained by converting the second generated power to the transmission line P; and a voltage detection means 38 for detecting the voltage Vp of the transmission line P; The first power conditioner 3 has a first generated power and an output power when the value of the voltage Vp of the transmission line P detected by the voltage detection means 38 is larger than a predetermined value VH. It is configured to perform power storage control to enable power storage device 2 (fifth configuration).

  According to the fifth configuration, the first generated power generated by the first power generators 1a and 10a by the power storage control performed when the value of the voltage Vp of the transmission line P is larger than the predetermined value VH The power storage device 2 can store the output power of the second power conditioner 4 output to the transmission line P. Therefore, when the value of the voltage Vp of the transmission line P between the commercial power system E and the first power conditioner 3 is increased, the first generated power of the first power generators 1a and 10a and the second power generator 1b, The second generated power of 10b can be used effectively.

DESCRIPTION OF SYMBOLS 100 Solar power generation system 100a Wind power generation system 1 Solar cell module 1a 1st solar cell module 1b 2nd solar cell module 10 Wind power generation device 10a 1st wind power generation device 10b 1st wind power generation device 2 Storage battery 3 1st power conditioner 4 Second power conditioner 31, 41 DC / DC converter 31a, 41a AC / DC converter 32 Bidirectional inverter 42 Inverter 33, 43 Capacitor 35, 45 Communication unit 36, 46 Memory 34 Bidirectional DC / DC converter 37 Electric energy meter 371 Electricity purchase meter 372 Electricity sale meter 39, 49 IC
391, 491 Power voltage comparison unit 392, 492 Conversion control unit BL Bus line 5 Controller 51 Input unit 52 Controller communication unit 53 Memory for controller 54 Controller IC
541 Storage amount monitoring unit 542 Storage / discharge control unit R Power receiving point P Transmission line E Commercial power system L Power load

Claims (5)

A power conditioner connected to the first power generation device and the power storage device and connected to the commercial power system via a transmission line,
When the value of the voltage of the transmission line detected by the voltage detecting means is larger than a predetermined value, the first generated power generated by the first power generator and the second generated by the second power generator A power conditioner including a control unit that performs power storage control that enables power storage in the power storage device with output power of another power conditioner that converts generated power and outputs the power to the transmission line.   The predetermined value is compared with the value of the voltage of the transmission line by the other power conditioner, and when the value of the voltage is larger, the second power conditioner The power conditioner according to claim 1, wherein the power conditioner is set to be less than a threshold value for reducing the amount of power conversion. A communication unit that communicates with the other inverter;
When the value of the voltage of the transmission line is larger than the predetermined value, the communication unit determines whether to reduce the power conversion amount of the second generated power by the other power conditioner. The power conditioner of Claim 1 which transmits the conversion control information used for 1 to the said other power conditioner. A power control method for a power conditioner that is connected to a first power generation device and a power storage device and connected to a commercial power system via a transmission line,
When the value of the voltage of the transmission line detected by the voltage detecting means is larger than a predetermined value, the first generated power generated by the first power generator and the second generated by the second power generator A power control method for a power conditioner, comprising a step of performing power storage control that enables the power storage device to store output power of another power conditioner that converts the generated power into power and outputs the power to the transmission line. A first power generator for outputting first generated power;
A second power generator that outputs second generated power;
A power storage device;
A first power conditioner connected to the first power generator and the power storage device and connected to a commercial power system via a transmission line;
A second power conditioner connected to the second power generation device and the transmission line and outputting output power obtained by converting the second generated power to the transmission line;
Voltage detection means for detecting the voltage of the transmission line;
With
The first power conditioner stores the first generated power and the output power in the power storage device when a value of the voltage of the transmission line detected by the voltage detecting unit is larger than a predetermined value. A power control system that performs power storage control.

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