JP2019004673A - Power conditioner, double electrical generating system, and method of controlling double electrical generating system - Google Patents

Abstract

To let a photovoltaic power generation panel exhibit electrical generating capacity in double electrical generation without any waste.SOLUTION: A power conditioner comprises: a first DC/DC converter connected to a photovoltaic power generation panel; a second DC/DC converter connected to a storage battery; a DC bus common to the first DC/DC converter and second DC/DC converter; an inverter provided between the DC bus and an alternating-current cable way; and a control part which performs basic control operation to control the first DC/DC converter, second DC/DC converter, and inverter so as to sell electric power generated by the photovoltaic power generation panel while managing electric power consumption by loads on the alternating current cable way by discharging the storage battery. The control part does not perform the basic control operation when the total of generated electric power which can be obtained from the photovoltaic power generation panel and the self-consumed electric power exceeds its output upper limit, and uses the generated electric power as self-consumed electric power while suppressing discharging electric power of the storage battery.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a power conditioner, a double power generation system, and a control method for a double power generation system.

  In a power generation configuration in which other private power generation facilities are provided in addition to a residential solar power generation facility, all of the power of the solar power generation can be sold if all the private power consumption can be covered by other private power generation facilities. Such a power generation form is generally called double power generation (see, for example, Non-Patent Document 1, Patent Documents 1 and 2). Other private power generation facilities are, for example, storage batteries, fuel cells, gas engine power generation, and the like. In the case of a storage battery, charging is performed during night hours when the electricity charge is cheap.

At present, reverse tides other than the power generated by photovoltaic power generation are regulated by the provisions related to grid interconnection. Therefore, the usage of the discharge power of the storage battery is only the consumer's own power consumption.
Moreover, as a power conditioner suitable for such double power generation, there is a hybrid type power conditioner capable of connecting a two-system DC input of a photovoltaic power generation panel and a storage battery (see, for example, Patent Documents 3 and 4). .)

JP 2013-78191 A JP 2014-73043 A JP 2017-28891 A JP 2017-77100 A

Material issued by the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry

  The output upper limit (≈input upper limit) of the hybrid type power conditioner depends on the main breaker capacity of a general household distribution board and is, for example, 6 kW. Therefore, if the power loss of conversion is ignored, the input upper limit for the power conditioner is also 6 kW in total. For example, if the maximum output of the photovoltaic power generation panel is 4 kW and the maximum output of the storage battery is 2 kW, the total input to the power conditioner does not exceed 6 kW.

  On the other hand, the photovoltaic power generation panel is influenced by the weather, time, solar altitude, atmospheric transmittance, temperature, etc., and cannot always produce the maximum output. Therefore, as a realistic choice, it is possible to install the photovoltaic power generation panel in a state of “overloading” exceeding the input upper limit of the inverter. However, when overloading is performed, if the power near the maximum output under overloading can be actually generated in a state close to ideal power generation conditions, the total input with the storage battery exceeds the input upper limit of the power conditioner. In such a state, the power exceeding the input upper limit cannot be taken in, and the power generation capacity is surplus.

  In view of such a problem, an object of the present invention is to make the power generation capability of a photovoltaic power generation panel in double power generation unnecessarily.

  A power conditioner according to an expression of the present invention is a power conditioner provided between a customer's AC circuit connected to a commercial power system and a plurality of DC power sources including a photovoltaic power generation panel and a storage battery. The first DC / DC converter connected to the photovoltaic power generation panel, the second DC / DC converter connected to the storage battery, the first DC / DC converter, and the second DC / DC A DC bus common to the converter, an inverter provided between the DC bus and the AC circuit, the first DC / DC converter, the second DC / DC converter, and the inverter are controlled. The basic control operation of selling the electric power generated by the photovoltaic power generation panel while covering the private power consumption due to the load of the AC electric circuit by discharging the storage battery A control unit, and the control unit, when the total of the generated power that can be drawn from the photovoltaic power generation panel and the private power consumption exceeds the upper limit of its own output, regardless of the basic control operation, It is a power conditioner which suppresses the discharge power of the storage battery and charges the generated power to the private power consumption.

  Moreover, the double power generation system according to an expression of the present invention is a consumer AC circuit connected to a commercial power system, a load connected to the AC circuit, and the commercial power system connected to the AC circuit. A grid-connected power conditioner, a storage battery connected to the power conditioner, and a solar power generation panel connected to the power conditioner and sharing a DC bus with the storage battery in the power conditioner. , A double power generation system having a basic control operation of selling power generated by the photovoltaic power generation panel while covering private power consumption by the load by discharging the storage battery, wherein the power conditioner is If the sum of the generated power that can be drawn from the solar power generation panel and the private power consumption exceeds the output limit of the self, Irrespective of the control operation, to suppress the discharge power of the storage battery devote the generated power to the self-power consumption, a double power generation system.

  Further, the control method of the double power generation system according to one expression of the present invention is such that, in the double power generation system in which the photovoltaic power generation panel and the storage battery are connected to a common power conditioner and connected to the AC power line, the power conditioner is A control method of a double power generation system to be executed, wherein basic control is to sell power generated by the photovoltaic power generation panel while providing self-power consumption by a load connected to the AC power line by discharging the storage battery When the total of the generated power that can be drawn out from the photovoltaic power generation panel and the private power consumption exceeds the upper limit of the AC power output of the power conditioner, the storage battery is used regardless of the basic control operation. This is a control method for a double power generation system in which the generated power is suppressed and the generated power is charged to the private power consumption.

  ADVANTAGE OF THE INVENTION According to this invention, the power generation capability of a photovoltaic power generation panel can be exhibited without waste, making double power generation a basic control operation.

It is a single line connection figure which shows an example of a structure of the double electric power generation system installed in small consumers, such as a general household. FIG. 2 is a single line connection diagram showing the power of each part when the generated power of the photovoltaic power generation panel is 4 kW in the configuration of FIG. 1. FIG. 2 is a single line connection diagram showing the power of each part when the generated power of the photovoltaic power generation panel is 5 kW in the configuration of FIG. 1. FIG. 2 is a single line connection diagram showing the power of each part when the generated power of the photovoltaic power generation panel is 6 kW in the configuration of FIG. 1. FIG. 2 is a single line connection diagram showing the power of each part when the generated power of the photovoltaic power generation panel is 7 kW in the configuration of FIG. 1. It is a figure which shows an example of the internal circuit of a power conditioner. It is an example of the flowchart which shows the algorithm of the control regarding charging / discharging of a storage battery.

[Summary of Embodiment]
The gist of the embodiment of the present invention includes at least the following.

  (1) This is a power conditioner provided between an AC power circuit of a consumer connected to a commercial power system and a plurality of DC power sources including a solar power generation panel and a storage battery, and the solar power generation panel The first DC / DC converter connected to the storage battery, the second DC / DC converter connected to the storage battery, the DC bus common to the first DC / DC converter and the second DC / DC converter And an inverter provided between the DC bus and the AC circuit, the first DC / DC converter, the second DC / DC converter, and the inverter to control the load of the AC circuit A control unit configured to perform basic control operation of selling electric power generated by the photovoltaic power generation panel while providing private power consumption by the discharge of the storage battery. The unit suppresses the discharge power of the storage battery regardless of the basic control operation when the total of the generated power that can be drawn from the photovoltaic power generation panel and the self-consumed power exceeds the upper limit of its own output. It is a power conditioner which allocates generated electric power to the said private power consumption.

  In the power conditioner configured as described above, as a basic control operation, it is possible to perform double power generation in which the power generated by the photovoltaic power generation panel is sold while the private power consumption by the load is covered by the discharge of the storage battery. . On the other hand, if the sum of the power generated by the photovoltaic power generation panel and the power consumed by the individual exceeds the output limit of the self, if the storage battery is discharged as it is, a part of the power that can be generated by the photovoltaic power generation panel is not used. become. Therefore, in such a case, regardless of the basic control operation, the discharge power of the storage battery is suppressed and the power generated by the photovoltaic power generation panel is used for self-consumption power. As a result, the power generation capability of the photovoltaic power generation panel can be exhibited without waste while making double power generation a basic control operation.

(2) Moreover, in the power conditioner of (1), when the generated power that can be drawn from the photovoltaic power generation panel reaches the upper limit of the input of the power conditioner, the control unit uses the generated power to generate the storage battery. May be charged.
For example, when the generated power of the overloaded solar power generation panel reaches the input upper limit of the power conditioner, the solar power generation panel may be able to input more generated power to the power conditioner. However, the input upper limit is approximately equal to the output upper limit, and power exceeding the output upper limit cannot be output to the AC side. Therefore, if the power of the DC bus is consumed by charging the storage battery, much DC power can be drawn from the photovoltaic power generation panel.

  (3) Moreover, this is a power condition connected to a commercial power system, connected to the AC power circuit, and connected to the commercial power system. And a storage battery connected to the power conditioner, and a photovoltaic power generation panel connected to the power conditioner and sharing the DC battery with the storage battery in the power conditioner, and self-consumption by the load It is a double power generation system whose basic control operation is to sell electric power generated by the photovoltaic power generation panel while supplying electric power by discharging the storage battery, and the power conditioner can be drawn from the solar power generation panel When the sum of the generated power and the private power consumption exceeds the output upper limit of the self, the power storage is performed regardless of the basic control operation. Devote the generated power to the self power consumption of the discharge power suppression is a double power generation system.

  In the double power generation system configured as described above, as the basic control operation, the power generated by the photovoltaic power generation panel can be sold while the private power consumption by the load is covered by the discharge of the storage battery. On the other hand, if the sum of the power generated by the photovoltaic power generation panel and the power consumed by the individual exceeds the output limit of the self, if the storage battery is discharged as it is, a part of the power that can be generated by the photovoltaic power generation panel is not used. become. Therefore, in such a case, regardless of the basic control operation, the discharge power of the storage battery is suppressed and the power generated by the photovoltaic power generation panel is used for self-consumption power. As a result, the power generation capability of the photovoltaic power generation panel can be exhibited without waste while making double power generation a basic control operation.

  (4) Further, from the viewpoint of the method, the double power generation system executed by the power conditioner in a double power generation system in which the photovoltaic power generation panel and the storage battery are connected to a common power conditioner and grid-connected to the AC power circuit. In the control method, executing the basic control operation to sell the electric power generated by the photovoltaic power generation panel while covering the private power consumption by the load connected to the AC electric circuit by discharging the storage battery, When the total of the generated power that can be drawn from the photovoltaic power generation panel and the private power consumption exceeds the upper limit of the AC power output of the power conditioner, the discharge power of the storage battery is suppressed regardless of the basic control operation. This is a control method for a double power generation system in which the generated power is used for the private power consumption.

  According to such a control method of the double power generation system, as the basic control operation, the power generated by the photovoltaic power generation panel can be sold while the self-consumption power by the load is covered by the discharge of the storage battery. On the other hand, if the sum of the power generated by the photovoltaic power generation panel and the power consumed by the individual exceeds the upper limit of the AC power output of the inverter, if the storage battery is discharged as it is, one of the power that can be generated by the photovoltaic power generation panel. Department will not be used. Therefore, in such a case, regardless of the basic control operation, the discharge power of the storage battery is suppressed and the power generated by the photovoltaic power generation panel is used for self-consumption power. As a result, the power generation capability of the photovoltaic power generation panel can be exhibited without waste while making double power generation a basic control operation.

[Details of the embodiment]
Hereinafter, a power conditioner according to an embodiment of the present invention and a double power generation system including the power conditioner (including a control method thereof) will be described with reference to the drawings.

《Example of double power generation system configuration》
FIG. 1 is a single-line connection diagram illustrating an example of a configuration of a double power generation system 100 installed in a small-scale consumer such as a general household. In the figure, a hybrid power conditioner 1 that can be connected to a plurality of DC power sources is connected to a photovoltaic power generation panel 2 and a storage battery 3. In addition, although the figure has shown the simple example, the photovoltaic power generation panel 2 and the storage battery 3 have multiple systems, respectively, and these and the power conditioner 1 may be connected. The storage battery 3 is a large-capacity secondary battery for electric power, for example, a lithium ion battery.

  The power conditioner 1 can convert direct current to alternating current or vice versa, and is connected to the distribution board 4 on the alternating current side. The distribution board 4 is connected to the commercial power system 5. In addition, a load 6 of a consumer who consumes private power is connected to the distribution board 4. The alternating current side of the power conditioner 1 is an alternating current circuit 7 in general terms.

Here, the symbols in FIG. 1 represent the following power.
“PV_o” represents the generated power output from the photovoltaic power generation panel 2 to the power conditioner 1, in other words, the generated power that the power conditioner 1 can draw from the photovoltaic power generation panel 2 by MPPT (Maximum Power Point Tracking) control. Yes.
“BT_o” represents the discharge power output from the storage battery 3 to the power conditioner 1. When the sign is negative, charging power is used.
“AC_o” represents the AC power going out from the power conditioner 1.
“GR” represents reverse power (power sold) due to grid interconnection with the commercial power grid 5.
“LD” represents private power consumption by the load 6.

  The power conditioner 1 has an output upper limit (≈input upper limit) of 6 kW, for example. If power loss due to power conversion is ignored, the upper limit of input can be considered to be 6 kW. In the following description, it is assumed that the input upper limit and the output upper limit are equal to each other. Further, for example, it is assumed that the discharge upper limit of the discharge power BT_o of the storage battery 3 is 2 kW. At present, if the private power consumption LD is 2 kW and the generated power PV_o of the photovoltaic power generation panel 2 is 3 kW, the input power to the power conditioner 1 is 5 kW, which is lower than the input upper limit. The power AC_o going out from the inverter 1 to the AC side is also 5 kW, 2 kW of which is consumed by the load 6, and the remaining 3 kW becomes the reverse tide power GR.

Hereinafter, FIG. 2 to FIG. 5 show what happens when the generated power PV_o of the photovoltaic power generation panel 2 increases.
First, FIGS. 1 to 2 show an example in which the generated power PV_o of the photovoltaic power generation panel 2 is increased from 3 kW to 4 kW. In the case of FIG. 2, the total input power of the generated power PV_o (4 kW) and the discharge power BT_o (2 kW) is the input upper limit of the power conditioner 1. The power AC_o going out from the inverter 1 to the AC side is 6 kW, 2 kW of which is consumed by the load 6, and the remaining 4 kW becomes the reverse power GR.
Up to this point, this is the normal double power generation concept.

  Now, FIGS. 2 to 3 show an example in which the generated power PV_o of the photovoltaic power generation panel 2 increases from 4 kW to 5 kW. In the case of FIG. 3, the total input power of the generated power PV_o (5 kW) and the discharge power BT_o exceeds the input upper limit of the power conditioner 1 if the discharge power BT_o is 2 kW. In the conventional double power generation, the power conditioner 1 that senses that the input upper limit is exceeded is set to 4 kW of power drawn from the solar power generation panel 2. In other words, when viewed from the photovoltaic power generation panel 2, an output of 5 kW is possible, but only 4 kW can be drawn.

  Therefore, in order not to do so, the power conditioner 1 suppresses the discharge power received from the storage battery 3. In the example of FIG. 3, the discharge power of the storage battery 3 that can output 2 kW is reduced to 1 kW. Thereby, the power conditioner 1 can accept the maximum generated power (5 kW) that can be drawn from the photovoltaic power generation panel 2 at the present time. In this case, the electric power AC_o going out from the power conditioner 1 to the AC side is 6 kW, 2 kW of which is consumed by the load 6, and the remaining 4 kW becomes the reverse tide power GR. That is, 1 kW of the generated power 5 kW is allocated to the private power consumption of the load 6. The load 6 consumes 1 kW of the discharge power BT_o and 1 kW of the generated power PV_o (5 kW) in total 2 kW.

  Further, FIGS. 3 to 4 show an example in which the generated power PV_o of the photovoltaic power generation panel 2 is increased from 5 kW to 6 kW. In this case, since the generated power PV_o alone becomes an input upper limit of the power conditioner 1, the power conditioner 1 completely suppresses the discharge of the storage battery 3 and stops the discharge (BT_o = 0 kW). In this case, the electric power AC_o going out from the power conditioner 1 to the AC side is 6 kW, 2 kW of which is consumed by the load 6, and the remaining 4 kW becomes the reverse tide power GR. That is, 2 kW of the generated power 6 kW is allocated to the private power consumption of the load 6.

  4 to 5 show an example where the generated power PV_o of the photovoltaic power generation panel 2 is increased from 6 kW to 7 kW. In addition, the circuit element in the power conditioner 1 connected with the photovoltaic power generation panel 2 shall endure receiving 7kW. However, the output upper limit is 6 kW and does not change. In this case, since the input upper limit of the power conditioner 1 exceeds the generated power PV_o alone, the power conditioner 1 further suppresses the discharge power than BT_o = 0, that is, charges the storage battery 3 and uses 1 kW for charging. (BT_o = -1 kW). Thereby, the input power to the power conditioner 1 becomes 7 kW + (− 1) kW = 6 kW, which is within the input upper limit.

  Also in this case, the power AC_o going out from the power conditioner 1 to the AC side is 6 kW, 2 kW of which is consumed by the load 6, and the remaining 4 kW becomes the reverse power GR. That is, 2 kW of the generated power 7 kW is used for the private power consumption of the load 6.

  In addition, although the above description showed what happened when the electric power PV_o of the photovoltaic power generation panel 2 increased, when the electric power PV_o decreases from the state of FIG. 5, FIG. 5, FIG. , FIG. 3 and FIG. Moreover, the change in state is reversible and arbitrary, and can change arbitrarily from one state to another.

<Example of inverter circuit>
FIG. 6 is a diagram illustrating an example of an internal circuit of the power conditioner 1. First, the main circuit components will be described. The DC side capacitor 11 is connected in parallel to the input from the photovoltaic power generation panel 2. The DC reactor 12 and the switching elements Q1 and Q2 constitute a DC / DC converter CV1. The DC / DC converter CV1 is connected to the DC bus 15.

  Similarly, the DC side capacitor 13 is connected in parallel to the storage battery 3. The DC reactor 14 and the switching elements Q3 and Q4 constitute a DC / DC converter CV2. The DC / DC converter CV2 is connected to the DC bus 15.

  An intermediate capacitor 16 and an inverter INV are connected to the DC bus 15. The inverter INV is a full-bridge connection of switching elements Q5, Q6, Q7, Q8, Q9, and Q10. The AC side of the inverter INV is a single-phase three-wire (U-line, O-line, W-line) electric circuit, and is connected to the AC electric circuit 7 via an AC reactor 17 and a grid interconnection relay 18.

  As elements for measurement and control, a current sensor 1a, a voltage sensor 1b, a current sensor 1c, and a voltage sensor 1d are provided on the direct current side. The current sensor 1 a detects a current flowing through the DC reactor 12. The voltage sensor 1 b detects the voltage across the DC side capacitor 11. The current sensor 1 c detects a current flowing through the DC reactor 14. The voltage sensor 1 d detects the voltage across the DC side capacitor 13. On the AC side, current sensors 1e, 1f, 1g and voltage sensors 1h, 1j, 1k are provided. Current sensors 1e, 1f, and 1g detect currents flowing through the U line, the O line, and the W line of the AC reactor 17, respectively. The voltage sensors 1h, 1j, and 1k detect the U-O line voltage, the W-O line voltage, and the U-W line voltage, respectively.

  The detection output of each sensor is sent to the control unit 19. Based on this, the control unit 19 controls the switching elements Q1 and Q2 of the DC / DC converter CV1, the switching elements Q3 and Q4 of the DC / DC converter CV2, and the switching elements Q6 to Q10 of the inverter INV. The control unit 19 includes, for example, a computer, and implements necessary control functions by causing the computer to execute software (computer program). The software is stored in a storage device (not shown) of the control unit 19.

Here, assuming that the current detected by the current sensor 1a is I _PV and the voltage detected by the voltage sensor 1b is V _PV , the power generation output PV_o of the solar power generation panel 2 described above is
PV_o = I _PV × V _PV (1)
As follows. In addition, when there are a plurality of sets (= n sets) of circuits from the solar power generation panel 2 to the DC bus 15, the following is obtained.
PV_o =
(I _PV1 × V _PV1 ) + (I _PV2 × V _PV2 ) +... + (I _PVn × V _PVn )
... (1 ')

Further, when current _{I BT} current sensor 1c detects a voltage which the voltage sensor 1d for detecting the _{V BT,} discharge power (or charge power) BT_o of the aforementioned storage battery,
_{BT_o = I BT × V BT ···} (2)
As follows. In addition, when there are a plurality of sets (= m sets) from the storage battery 3 to the DC bus 15, it is obtained as follows.
BT_o =
_{(I BT1 × V BT1) +} (I BT2 × V BT2) + ··· + (I BTm × V BTm)
... (2 ')

On the other hand, the self-power consumption LD is P _uw , the U-W line power obtained from the detection outputs of the current sensors 1e, 1f, 1g and the voltage sensors 1h, 1j, 1k, and the U-O line power P _uo. , If the power between W-O lines is _Pwo ,
_{LD = P uw -P uo -P wo} ··· (3)
It can ask for.

《Control algorithm》
Next, an algorithm for control related to charging / discharging of the storage battery 3 will be described. FIG. 7 is an example of a flowchart showing a control algorithm related to charging / discharging of the storage battery 3. The execution subject of the flowchart is the control unit 19.

(Explanation for FIG. 1)
First, the state of FIG. 1 will be described by applying it to the processing of the flowchart of FIG.
The control unit 19 first calculates the generated power PV_o and the private power consumption LD (step S1). In the case of FIG. 1, PV_o is calculated as 3 kW, and LD is calculated as 2 kW. Subsequently, the control unit 19 determines whether PV_o (= 3 kW) is equal to or higher than the input upper limit (= 6 kW) of the power conditioner 1 (step S2).

Since the determination is “No”, the control unit 19 next determines whether PV_o (= 3 kW) is larger than the discharge upper limit (= 2 kW) (step S3). Since the determination is “Yes”, the control unit 19 next determines whether or not the self-power consumption LD (= 2 kW) is greater than (output upper limit (= 6 kW) −PV_o (= 3 kW)) (step) S4). When PV_o on the right side of the determination formula in step S4 is moved to the left side,
LD + PV_o> Output upper limit (4)
It becomes. That is, it is determined whether or not the sum of the generated power PV_o and the private power consumption LD exceeds its own output upper limit. Since this determination is “No”, the control unit 19 sets the discharge power BT_o to the same value as the private power consumption (= 2 kW), that is, 2 kW (step S6).

  In FIG. 1, if the generated power is 2 kW or less, the determination in Step S3 is “No”, so the control unit 19 goes straight to Step S6 and sets the discharge power BT_o as self-consumed power (= 2 kW). The same value, that is, 2 kW is set (step S6). The reverse power GR is the same value as the generated power. After execution of step S6, the process returns to step S1, and the same process is repeated as long as the state does not change.

(Explanation for FIG. 2)
Next, the state of FIG. 2 will be described by applying it to the processing of the flowchart of FIG.
The control unit 19 first calculates the generated power PV_o and the private power consumption LD (step S1). In the case of FIG. 2, PV_o is calculated as 4 kW, and LD is calculated as 2 kW. Subsequently, the control unit 19 determines whether PV_o (= 4 kW) is greater than or equal to the input upper limit (= 6 kW) of the power conditioner 1 (step S2).

  Since the determination is “No”, the control unit 19 next determines whether PV_o (= 4 kW) is larger than the discharge upper limit (= 2 kW) (step S3). Since the determination is “Yes”, the control unit 19 next determines whether or not the self-power consumption LD (= 2 kW) is greater than (output upper limit (= 6 kW) −PV_o (= 4 kW)) (step) S4). Since the determination is “No”, the control unit 19 sets the discharge power BT_o to the same value as the private power consumption (= 2 kW), that is, 2 kW (step S6). The reverse power GR is the same value as the generated power. After execution of step S6, the process returns to step S1, and the same process is repeated as long as the state does not change.

(Explanation for FIG. 3)
Next, the state of FIG. 3 will be described by applying it to the processing of the flowchart of FIG.
The control unit 19 first calculates the generated power PV_o and the private power consumption LD (step S1). In the case of FIG. 3, PV_o is calculated as 5 kW, and LD is calculated as 2 kW. Subsequently, the control unit 19 determines whether PV_o (= 5 kW) is equal to or higher than the input upper limit (= 6 kW) of the power conditioner 1 (step S2).

  Since the determination is “No”, the control unit 19 next determines whether PV_o (= 5 kW) is larger than the discharge upper limit (= 2 kW) (step S3). Since the determination is “Yes”, the control unit 19 next determines whether or not the self-power consumption LD (= 2 kW) is greater than (output upper limit (= 6 kW) −PV_o (= 5 kW)) (step) S4). Here, since the determination is “Yes”, the control unit 19 sets the discharge power BT_o to the output upper limit (= 6 kW) −PV_o (= 5 kW), that is, 1 kW (step S5). Thereby, the discharge power is suppressed. After execution of step S5, the process returns to step S1, and the same process is repeated as long as the state does not change.

(Explanation for FIG. 4)
Next, the state of FIG. 4 will be described by applying it to the processing of the flowchart of FIG.
The control unit 19 first calculates the generated power PV_o and the private power consumption LD (step S1). In the case of FIG. 4, PV_o is calculated as 6 kW, and LD is calculated as 2 kW. Subsequently, the control unit 19 determines whether PV_o (= 6 kW) is greater than or equal to the input upper limit (= 6 kW) of the power conditioner 1 (step S2).

  Here, since the determination is “Yes”, the control unit 19 next sets the charging power to (PV_o (= 6 kW) −input upper limit (= 6 kW)), that is, 0 kW (step S7). That is, the storage battery 3 is not discharged and is not charged. Next, the control unit 19 determines whether or not the charging power (= 0 kW) is larger than the charging upper limit (for example, 2 kW) (step S8). The determination is “No”, and the process returns to step S1. Thereafter, as long as the state does not change, the same processing is repeated.

(Explanation for FIG. 5)
Next, the state of FIG. 5 will be described by applying it to the processing of the flowchart of FIG.
The control unit 19 first calculates the generated power PV_o and the private power consumption LD (step S1). In the case of FIG. 5, PV_o is calculated as 7 kW, and LD is calculated as 2 kW. Subsequently, the control unit 19 determines whether PV_o (= 7 kW) is equal to or higher than the input upper limit (= 6 kW) of the power conditioner 1 (step S2).

  Here, since the determination is “Yes”, the control unit 19 then sets the charging power to (PV_o (= 7 kW) −input upper limit (= 6 kW)), that is, 1 kW (step S7). That is, the storage battery 3 is charged at 1 kW. Next, the control unit 19 determines whether or not the charging power (= 1 kW) is larger than the charging upper limit (for example, 2 kW) (step S8). The determination is “No”, and the process returns to step S1. Thereafter, as long as the state does not change, the same processing is repeated. If the determination in step S8 is “Yes”, the control unit 19 suppresses the charging power to the charging upper limit (step S9).

<Summary>
As described above, the control unit 19 of the power conditioner 1 sells the generated power PV_o of the photovoltaic power generation panel 2 while covering the self-consumed power LD by the load 6 of the AC circuit 7 by discharging the storage battery 3. In other words, double power generation is the basic control operation. And as shown by Formula (4), the control part 19 suppresses discharge electric power irrespective of basic control operation | movement, when the sum total of generated electric power and private power consumption exceeds an own output upper limit. The generated power is used for private power consumption.

  In the power conditioner 1 that performs control of double power generation, when the sum of the generated power of the photovoltaic power generation panel 2 and the private power consumption exceeds the upper limit of its own output, if the storage battery 3 is discharged as it is, the photovoltaic power generation A part of the electric power that can be generated by the panel 2 is not used. Therefore, in such a case, the discharge power of the storage battery 3 is suppressed and the generated power of the photovoltaic power generation panel 2 is used for private power consumption, regardless of the basic control operation. Thereby, the power generation capability of the photovoltaic power generation panel 2 can be exhibited without waste while making double power generation a basic control operation.

  In addition, instead of “exceeding its own output upper limit”, it can be set as “exceeding its own input upper limit”. However, considering the power loss of power conversion, input upper limit> output upper limit, If the input upper limit is exceeded, it will always exceed its own output upper limit.

Further, for example, when the generated power of the overloaded photovoltaic power generation panel 2 reaches the input upper limit of the power conditioner 1, there is a possibility that the photovoltaic power generation panel 2 can input more generated power to the power conditioner. is there. However, the input upper limit is approximately equal to the output upper limit, and power exceeding the output upper limit cannot be output to the AC side.
Therefore, when the generated power of the photovoltaic power generation panel 2 reaches the input upper limit of the power conditioner 1, the control unit 19 charges the storage battery 3 using the generated power. In this way, if the power of the DC bus 15 is consumed by charging the storage battery 3, much DC power can be drawn from the photovoltaic power generation panel 2.

《Supplementary Note》
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Power conditioner 2 Solar power generation panel 3 Storage battery 4 Distribution board 5 Commercial power system 6 Load 7 AC circuit 11 DC side capacitor 12 DC reactor 13 DC side capacitor 14 DC reactor 15 DC bus 16 Intermediate capacitor 17 AC reactor 18 System connection System relay 19 Control unit 1a Current sensor 1b Voltage sensor 1c Current sensor 1d Voltage sensor 1e, 1f, 1g Current sensor 1h, 1j, 1k Voltage sensor 100 Double power generation system CV1, CV2 DC / DC converter INV Inverter

Claims (4)

A power conditioner provided between an AC power circuit of a consumer connected to a commercial power system and a plurality of DC power sources including a photovoltaic power generation panel and a storage battery,
A first DC / DC converter connected to the photovoltaic panel;
A second DC / DC converter connected to the storage battery;
A DC bus common to the first DC / DC converter and the second DC / DC converter;
An inverter provided between the DC bus and the AC circuit;
The first DC / DC converter, the second DC / DC converter, and the inverter are controlled, and the private power consumption due to the load of the AC circuit is covered by the discharge of the storage battery, and A control unit that performs basic control operation to sell power to be generated, and
The control unit suppresses the discharge power of the storage battery regardless of the basic control operation when the sum of the generated power that can be drawn from the photovoltaic power generation panel and the private power consumption exceeds the output upper limit of the self. A power conditioner that allocates the generated power to the private power consumption.   The power conditioner according to claim 1, wherein when the generated power that can be drawn from the photovoltaic power generation panel reaches an input upper limit of the power conditioner, the control unit charges the storage battery using the generated power. AC power circuit of consumers connected to the commercial power system,
A load connected to the AC circuit;
A power conditioner connected to the AC power circuit and interconnected with the commercial power system;
A storage battery connected to the inverter;
A photovoltaic panel connected to the power conditioner and sharing a DC bus with the storage battery in the power conditioner;
A double power generation system having a basic control operation of selling power generated by the photovoltaic power generation panel while providing private power consumption due to the load by discharging the storage battery,
The power conditioner suppresses the discharge power of the storage battery regardless of the basic control operation when the sum of the generated power that can be drawn from the photovoltaic power generation panel and the private power consumption exceeds the upper limit of its own output. A double power generation system that allocates the generated power to the private power consumption. A control method of a double power generation system that is executed by the power conditioner in a double power generation system that connects a photovoltaic power generation panel and a storage battery to a common power conditioner and is connected to an AC power line,
Performing as a basic control operation to sell the power generated by the photovoltaic power generation panel while covering private power consumption due to the load connected to the AC electric circuit by discharging the storage battery,
When the sum of the generated power that can be drawn from the photovoltaic power generation panel and the private power consumption exceeds the upper limit of the AC power of the power conditioner, the discharge power of the storage battery is suppressed regardless of the basic control operation. And the control method of a double electric power generation system which allocates the said generated electric power to the said private power consumption.

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