JP2019041554A - Power conditioner and transmission power control method thereof - Google Patents

Abstract

To solve the problem of a conventional power conditioner that the power to be transmitted to the system wiring is reduced by output control.SOLUTION: A power conditioner, where a solar cell panel and an accumulator battery are connected, brings transmission power close to transmittable power both in a case where the generated power is larger than the transmittable power, and a case where the generated power is smaller than the transmittable power, by compensating for the difference of the transmittable power, designated by an output control command value Pg* to be given externally, and the generated power of a solar cell panel 2 by charge discharge of the accumulator battery 3, by using a converter control section 21, a bidirectional DC/DC converter 22 and a maximum power point follow-up control section 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power conditioner and a transmission power control method thereof, and more particularly to a power conditioner that generates an AC power supply from a distributed power source using a solar cell panel and a power storage device in combination, and a transmission power control method thereof.

  In recent years, an AC power supply device (for example, a power conditioner) that sends out renewable energy generated by using a power generation device such as a solar battery panel or a windmill through a system wiring to which commercial power is supplied is widely used. A system that sends out renewable energy generated by a large number of power generation devices in this way to one system wiring is called a distributed power supply system. In addition, the amount of power generated by renewable energy varies depending on weather conditions. Therefore, in order to stabilize the voltage of the system wiring, it is necessary to stabilize the electric power sent from each power conditioner to the system wiring. Therefore, Patent Document 1 discloses a technique for stabilizing the transmission power.

  The solar power generation device described in Patent Document 1 includes a solar battery, a storage battery charged by the generated power of the solar battery, an inverter that converts direct current of the solar battery and the storage battery into alternating current, and an interconnection connection with the inverter. And a photovoltaic power generation device composed of a trademark electric power system. In this solar power generation device, the amount of electric power transmitted from the inverter is set to be large as the maximum amount of electric power generated by the solar cell. The battery is operated according to the determined power transmission pattern. When power generation exceeding the power transmission occurs, the surplus is charged to the storage battery, and when the generated power is insufficient, the power is supplemented by the storage battery. However, in the photovoltaic power generation apparatus described in Patent Document 1, the generated power is obtained by the product of the current value of the solar cell and the voltage of the storage battery, and power is generated at the maximum generated power point in consideration of the output characteristics of the solar cell. Therefore, there is a problem that power is not generated efficiently.

  Therefore, Patent Document 2 discloses a technique related to maximum power point tracking control that allows the maximum power generation capacity of a solar cell to be exhibited in a solar power generation system. In addition, when the maximum power point tracking control is performed, the power generation capacity of the solar cell can be maximized, but the power sent to the system wiring varies greatly due to fluctuations in power generation conditions such as solar radiation conditions. . For this reason, a commercial electric power company that manages the system wiring may make an output control request for limiting the transmission power to a certain level or less with respect to the power generation company. When this output control request is notified, the power generation company needs to limit the transmission power according to the output request. Therefore, Patent Document 2 also discloses an output control technique for suppressing the transmission power sent to the system wiring.

  The photovoltaic power generation system described in Patent Document 2 sets an operating voltage of a solar cell array, converts an inverter DC power output from the solar cell array into alternating current, and outputs current and voltage output from the solar cell array. A measuring unit that measures the operating voltage and output current value of the solar cell array measured by the measuring unit, a maximum power point tracking unit that calculates an operating voltage command value of the solar cell array, and the measuring unit Automatic voltage adjustment that compares the operation voltage value of the solar cell array obtained from the above and the operation voltage command value of the solar cell array set by the maximum power point tracking unit and performs proportional-integral control based on the difference A pulse width modulation signal generation unit that generates a gate signal of the inverter based on a current command value output from the automatic voltage adjustment unit, from sunrise to sunset, Having a power control unit for controlling the voltage command output by always maximum power point tracking, including the case of solar radiation, the. Moreover, in the solar power generation system of patent document 2, the said electric power control part is the operation voltage setting method of the said solar cell array at the time of electric power suppression, for every operation voltage setting of the said solar cell array in the said maximum power point tracking part. The measured power value is compared with the power suppression value to determine the voltage setting value.

Japanese Patent Laid-Open No. 1-303022 JP 2015-28694 A

  As described above, Patent Document 1 has a problem that the power generation efficiency of the solar cell cannot be maximized. On the other hand, by using the maximum power point tracking function described in Patent Document 2, it is possible to maximize the power generation efficiency of the solar cell. However, the renewable energy has a large voltage fluctuation, and the amount of the renewable energy sent to the system wiring becomes large, causing a problem in the stable operation of the commercial power network. Therefore, suppression of transmission power based on the output control request described in Patent Document 2 has been performed.

  In Patent Document 2, during the output control period, the power generation efficiency of the solar cell is suppressed from the original power generation efficiency by adjusting the voltage setting value that determines the output voltage of the solar cell. Therefore, in the solar power generation system described in Patent Document 2, there is a problem that the power generation efficiency is reduced during the output control period, and as a result, the power that can be sent to the system wiring is reduced.

  One aspect of the power conditioner according to the present invention includes a DC bus that transmits generated power generated by a solar cell panel, a branch DC bus that branches from a branch point provided on the DC bus, and the branch point. A converter control unit that detects a generated current and a generated voltage from the DC bus close to the solar panel and generates a charge / discharge current command value, and is provided between the branch DC bus and the power storage device, and the charge / discharge Sending current and sending voltage from a bidirectional DC / DC converter that charges and discharges the power storage device with a current amount according to a current command value, and the DC bus closer to the unidirectional DC / DC converter than the branch point A maximum power point tracking control unit that detects and generates a transmission current command value, and a transmission that supplies transmission DC power supplied from the DC bus to the system power supply based on the transmission current command value A unidirectional DC / AC converter for converting to flowing power, and the converter control unit is configured to send the sendable power based on the sendable power specified by the output control command value given from the outside and the generated power. The surplus power or the insufficient power of the generated power with respect to the power is calculated, and the charge / discharge current command value for causing the power storage device to charge / discharge with the amount of current corresponding to the surplus power or the insufficient power is generated, and the maximum power The point tracking control unit receives the output control command value and sets the voltage of the DC bus to a voltage that maximizes the generated power in a state independent of the transmittable power, and the generated power is the transmittable power. If the generated power is less than the sendable power, the send current command value is generated so that the send power is equal to or less than the sendable power. Out power to generate the delivery current command value such that the transmittable power or less and the generated power above.

  One aspect of a power conditioner transmission power control method according to the present invention includes a DC bus that transmits generated power generated by a solar cell panel, and a branch DC bus that is branched from a branch point provided on the DC bus. A bi-directional DC / DC converter that is provided between the branch DC bus and the power storage device and charges / discharges the power storage device with a current amount corresponding to a charge / discharge current command value, and based on a send current command value A unidirectional DC / AC converter for converting a transmission DC power given from a DC bus into a transmission AC power given to a system power supply, and a transmission power control method for a power conditioner according to an output control command value given from the outside Based on the specified sendable power and the generated power, the surplus power or the shortage of the generated power relative to the sendable power is calculated, and the surplus is calculated. The charge / discharge current command value is calculated based on the power or the amount of current corresponding to the insufficient power, and the generated power is received in a state independent of the sendable power in response to the output control command value. When the generated power is larger than the transmittable power, the transmitted AC power is less than the transmittable power, and when the generated power is smaller than the transmittable power, the transmitted power is The send current command value is calculated so as to be less than the sendable power and greater than the generated power.

  In the power conditioner and the transmitted power control method according to the present invention, the above configuration allows the solar panel to generate power with the maximum power generation efficiency even when there is an output control request, and cannot be transmitted to the system wiring. The surplus power can be stored in the storage battery. Further, in the power conditioner and the transmitted power control method according to the present invention, the generated power is smaller than the transmittable power specified by the output control request even when the solar cell panel is generated with the maximum power generation efficiency. In this case, the power generated by the solar battery panel stored in the storage battery is sent to the system wiring together with the generated power at that time. This

  According to the power conditioner and the transmission power control method thereof according to the present invention, the amount of generated power that can be transmitted to the system wiring can be maximized.

1 is a block diagram of a power conditioner according to a first embodiment. FIG. 1 is a block diagram of a converter control unit and a bidirectional DC / DC converter according to a first embodiment. It is a figure explaining operation | movement of the maximum electric power point tracking control part when output control is not performed in the power conditioner concerning Embodiment 1. FIG. It is a figure explaining operation | movement of the maximum electric power point tracking control part when the electric power generation amount of a solar cell panel is larger than the power which can be sent in the power conditioner concerning Embodiment 1. FIG. It is a figure explaining operation | movement of the maximum electric power point tracking control part when the electric power generation amount of a solar cell panel is smaller than the power which can be sent in the power conditioner concerning Embodiment 1. FIG. 4 is a timing chart for explaining a first operation of the power conditioner according to the first exemplary embodiment; 6 is a timing chart for explaining a second operation of the power conditioner according to the first exemplary embodiment;

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. The power conditioner 1 according to the first embodiment performs a linked operation that operates in conjunction with a commercial power supply SPS that supplies power generated by a power plant or the like to a consumer. In this interconnection operation, the power conditioner 1 according to the first embodiment generates transmission power to be sent to the commercial power source SPS using generated power generated by the solar battery panel 2 and discharged power discharged from the storage battery 3. To do.

  Here, the block diagram of the power conditioner 1 concerning Embodiment 1 is shown in FIG. In FIG. 1, a commercial power source SPS that is an output destination of transmission power output from the power conditioner 1, a solar battery panel 2 that supplies generated power to the power conditioner 1, and a storage battery 3 that is used by the power conditioner 1 are illustrated. It was.

  As shown in FIG. 1, the power conditioner 1 according to the first embodiment includes a first backflow prevention unit (eg, backflow prevention diode 11), a second backflow prevention unit (eg, backflow prevention diode 12), It has a power point tracking control unit 13, a unidirectional DC / AC converter 14, a converter control unit 21, and a bidirectional DC / DC converter 22. The power conditioner 1 according to the first embodiment includes a DC bus W1 and a branch DC bus W2 that branches from a branch point N1 provided on the DC bus W1. On the DC bus W1, a current detection unit 31 and a voltage detection unit 32 are provided upstream from the branch point N1 (for example, the solar cell panel 2 side), and downstream (for example, commercial power supply SPS) from the branch point N1. A current detection unit 33 and a voltage detection unit 34.

  The backflow prevention diode 11 is provided upstream of the branch point N1 (for example, the side to which the solar cell panel 2 is connected) in the DC bus W1, and current flows back from the branch point N1 to the solar cell panel 2. To prevent that. The backflow prevention diode 12 is provided on the downstream side of the branch point N1 (for example, the side where the unidirectional DC / AC converter 14 is provided) in the DC bus W1, and prevents the current flowing from the commercial power source SPS into the storage battery 3.

  The maximum power point tracking control unit 13 detects the transmission current Io and the transmission voltage Vo from the DC bus W1 closer to the unidirectional DC / DC converter 14 than the branch point N1, and generates a transmission current command value Isps *. The transmission current Io is acquired by the current detection unit 33, and the transmission voltage Vo is acquired by the voltage detection unit 34. Further, the maximum power point tracking control unit 13 receives the output control command value Pg * from the outside, and the sendable power that is sent from the unidirectional DC / AC converter 14 is specified by the output control command value Pg *. The value of the send current command value Isps * is adjusted so as not to exceed.

  The maximum power point tracking control unit 13 adjusts the output capability of the unidirectional DC / AC converter 14 according to the send current command value Isps * in a state where the output control request is not made according to the output control command value Pg *. The sending current Io is controlled so that the power generation efficiency of the battery panel 2 is the highest.

  Further, the maximum power point tracking control unit 13 performs the following control in a state where no output control request is made by the output control command value Pg *. When the generated power of the solar cell panel 2 is larger than the power that can be transmitted, the maximum power point tracking control unit 13 can transmit the transmitted power while setting the transmitted current to the transmitted current Io that maximizes the generated power of the solar cell panel 2. A transmission current command value Isps * that is equal to or lower than the power is generated. In addition, when the generated power of the solar cell panel 2 is larger than the sendable power, the maximum power point tracking control unit 13 sets the send voltage Vo of the DC bus W1 independent of the sendable power. The sending voltage Vo is set so as to maximize the power generation capacity. On the other hand, when the generated power is smaller than the sendable power, the maximum power point tracking control unit 13 sets the send current command value Isps * so that the send power is equal to or less than the sendable power and equal to or greater than the generated power of the solar battery panel 2. Generate. When the generated power of the solar cell panel 2 is smaller than the sendable power, the maximum power point tracking control unit 13 sets the send voltage Vo of the DC bus W1 independent of the sendable power and The sending voltage Vo is set so as to maximize the power generation capacity.

  The unidirectional DC / AC converter 14 converts the transmission DC power supplied from the DC bus W1 to the transmission AC power supplied to the commercial power source SPS based on the transmission current command value Isps *. This sending DC power is obtained by the product of the sending current Io and the sending voltage Vo. Further, the transmission AC power is hereinafter simply referred to as transmission power. In the example shown in FIG. 1, the unidirectional DC / AC converter 14 includes a unidirectional DC / DC converter 15 and an inverter 16. The unidirectional DC / DC converter 15 converts the output voltage Vo into a predetermined DC voltage while adjusting the amount of current output based on the output current command value Isps *. The inverter 16 converts a DC voltage into an AC voltage. The power output from the inverter 16 is the output power.

  The converter control unit 21 detects the generated current Ipv and the generated voltage Vi from the DC bus W1 closer to the solar cell panel 2 than the branch point N1, and generates a charge / discharge current command value Is *. In generating this charge / discharge current command value Is *, converter control unit 21 refers to output control command value Pg *. Specifically, the converter control unit 21 determines the surplus power of the generated power relative to the sendable power based on the sendable power specified by the output control command value Pg * given from the outside and the generated power of the solar battery panel 2 or The shortage power is calculated, and the charge / discharge current command value Is * is generated so that the power storage device 3 is charged / discharged with a current amount corresponding to surplus power or shortage power. Details of the converter control unit 21 will be described later.

  Bidirectional DC / DC converter 22 is provided between branch DC bus W2 and power storage device 3, and has a current amount (for example, charge / discharge current Is) corresponding to charge / discharge current command value Is *. Charge and discharge.

  Here, the converter control unit 21 and the bidirectional DC / DC converter 22 will be described in detail. FIG. 2 shows a block diagram of the converter control unit 21 and the bidirectional DC / DC converter 22 according to the first embodiment. As shown in FIG. 2, the converter control unit 21 includes a generated power calculation unit 41, a low-pass filter 42, a power ratio calculation unit (for example, a divider 43), a charge / discharge coefficient calculation unit (for example, an adder 44), a charge / discharge. A current command value calculation unit (for example, a multiplier 45) is included. The bidirectional DC / DC converter 22 includes a PWM control unit 51.

The generated power calculation unit 41 calculates the generated power Ppv based on the generated current Ipv detected by the current detection unit 31 and the generated voltage Vo detected by the voltage detection unit 32. The generated power calculation unit 41 calculates the generated power Ppv by obtaining the product of the generated current Ipv and the generated voltage Vi. The low pass filter 42 removes noise caused by sudden fluctuations in the generated power Ppv by calculating an average value of the generated power Ppv acquired during a predetermined period. The divider 43 calculates a power ratio indicating a ratio between the transmittable power indicated by the output control command value Pg * and the generated power Ppv. The adder 44 calculates the charge / discharge coefficient M by adding the power ratio calculated by the divider 43 to -1. The charge / discharge coefficient M indicates the surplus power in the generated power Ppv or the insufficient power ratio of the generated power Ppv. The charge / discharge coefficient M calculated by the adder 44 is expressed by equation (1).
M = (Pg * / Ppv) −1 (1)
Multiplier 45 outputs the product of generated current Ipv and charge / discharge coefficient M as charge / discharge current command value Is *. This charge / discharge current command value Is * is expressed by equation (2).
Is * = M * Ipv (2)

  The PWM control unit 51 generates a PWM signal having a duty ratio corresponding to the charge / discharge current command value Is *. The direct current / direct current converter 52 applies a charge / discharge current Is to the storage battery 3 in accordance with the PWM signal duty ratio output from the PWM controller 51. At this time, the DC / DC converter 52 converts the DC voltage value of the branch DC bus W2 (or DC bus W1) into a DC voltage value to be given to the storage battery 3.

Here, the magnitude | size of the charging / discharging electric current Is charged / discharged to the storage battery 3 by the converter control part 21 and the bidirectional | two-way DC / DC converter 22 with reference to (1) Formula and (2) Formula is demonstrated. By substituting the charge / discharge coefficient M of equation (1) into equation (2), equation (3) can be obtained.
Is * = ((Pg * / Ppv) -1) Ipv
= (Pg * / Vi * Ipv) Ipv-Ipv)
= Pg * / Vi-Ipv
= (Vo × Io) / Vi-Ipv (3)
Here, the sending voltage Vo and the generated voltage Vi are the same voltage of the DC bus W1, and are the same voltage. The sending current Io is a total value of the generated current Ipv and the charging / discharging current Is. For this reason, equation (3) can be transformed into equation (4).
Is * = (Vi × (Ipv−Is)) / Vi−Ipv
= Ipv-Is-Ipv
= Is (4)

  That is, the converter control unit 21 calculates the ratio of the output control command value Pg * and the generated power Ppv as a power ratio, and how much the power currently generated is excessive with respect to the output control command value Pg *. Alternatively, whether the charge is insufficient or not is calculated as the charge / discharge coefficient M, and the product of the charge / discharge coefficient M and the generated current Ipv is used as the charge / discharge current command value Is *. By calculating the charge / discharge current command value Is * in this way, it is possible to determine how much current the storage battery 3 can charge / discharge to generate the transmission power corresponding to the output control command value Pg *. .

  Next, the operation of the power conditioner 1 according to the first embodiment will be described. Here, the operation of the maximum power point tracking control unit 13 will be described first. As described above, the maximum power point tracking control unit 13 has three operation modes. The first operation mode is an operation when the output control command value Pg * is not input. The second operation mode is an operation when the output control request is notified by the output control command value Pg * and the generated power of the solar cell panel 2 is larger than the sendable power. The third operation mode is an operation when the output control request is notified by the output control command value Pg * and the generated power of the solar cell panel 2 is smaller than the sendable power.

  FIG. 3 is a diagram for explaining the operation of the maximum power point tracking control unit 13 when the output control is not performed in the power conditioner 1 according to the first embodiment. As shown in FIG. 3, the maximum power point of the solar cell panel 2 can be plotted as a predetermined output curve. The maximum power point tracking control unit 13 generates a transmission current command value Isps * that is a transmission voltage Vo at which the transmission power is maximum according to this output curve. Thereby, the power conditioner 1 according to the first embodiment outputs the transmission power with the highest efficiency.

  FIG. 4 is a diagram illustrating the operation of the maximum power point tracking control unit 13 when the power generation amount of the solar cell panel 2 is larger than the sendable power in the power conditioner 1 according to the first embodiment. As shown in FIG. 4, in this case, if the solar cell panel 2 is generated with the maximum efficiency, the generated power is larger than the power that can be sent. Therefore, the maximum power point follow-up control unit 13 according to the first embodiment sets the send current command value Isps * to be given to the unidirectional DC / AC converter 14 to a current value smaller than the generated current Ipv generated by the power generation of the solar cell panel 2. The output current Io is suppressed to such an extent that it can be output. At this time, in the power conditioner 1 according to the first embodiment, the converter control unit 21 and the bidirectional DC / DC converter 22 draw the charging / discharging current Is to the storage battery 3 side through the branch DC bus W2, so that the transmission current Io The magnitude is made smaller than the generated current Ipv.

  FIG. 5 is a diagram for explaining the operation of the maximum power point tracking control unit 13 when the power generation amount of the solar battery panel 2 is smaller than the transmittable power in the power conditioner 1 according to the first embodiment. As shown in FIG. 5, in this case, even if the solar cell panel 2 is generated with the maximum efficiency, the sendable power becomes larger. Only the generated power of the solar battery panel 2 can output only the transmitted power that is less than the transmittable power. Therefore, the maximum power point follow-up control unit 13 according to the first embodiment sets the send current command value Isps * to be given to the unidirectional DC / AC converter 14 to a current value larger than the generated current Ipv generated by the power generation of the solar cell panel 2. The output current Io is increased to such an extent that it can be output. At this time, in the power conditioner 1 according to the first embodiment, the converter control unit 21 and the bidirectional DC / DC converter 22 discharge the charging / discharging current Is to the DC bus W1 via the branch DC bus W2, The magnitude of the sending current Io is made larger than the generated current Ipv.

  As shown in FIGS. 4 and 5, the maximum power point follow-up control unit 13 has a maximum during the period when the storage battery 3 is charged and discharged by the converter control unit 21 and the bidirectional DC / DC converter 22. The output characteristic curve obtained by shifting the output characteristic curve that follows the power point from the output characteristic curve obtained from the original output characteristic of the solar cell panel 2 is used.

  As described above, in the power conditioner 1 according to the first embodiment, the converter control unit 21 and the bidirectional DC / DC converter 22 absorb the difference from the output power of the generated power Ppv by charging / discharging the storage battery 3. Thus, most of the generated power can be sent to the commercial power supply SPS. Thus, the operation of the entire power conditioner according to the first embodiment will be described below.

FIG. 6 shows a timing chart for explaining the first operation of the power conditioner according to the first embodiment, and FIG. 7 shows a timing chart for explaining the second operation of the power conditioner according to the first embodiment. The difference between the first operation and the second operation is the magnitude of transmittable power. In the second operation, the transmittable power is set smaller than that of the first operation.
As shown in FIGS. 6 and 7, the power conditioner 1 according to the first embodiment charges the storage battery 3 with the surplus generated power during a period in which the generated power Ppv is higher than the sendable power ( Timing T10 to T11, T20 to T21). And when the generated power Ppv of the solar cell panel 2 is lower than the transmittable power, the generated power Ppv can be transmitted by discharging the power charged in the storage battery 3 at timings T10 to T11 (or timings T20 to T21). The difference with electric power is compensated (timing T11-T12, T21-T22). Furthermore, in the power conditioner 1 according to the first exemplary embodiment, even if the power generation of the solar battery panel 2 is not performed, if the rechargeable power remains in the storage battery 3, the discharge is less than the power that can be sent. The storage battery 3 is discharged with the capacity (timing T12 to T13, T22 to T23).

  Here, referring to FIGS. 6 and 7, in the power conditioner 1 according to the first embodiment, even if the dischargeable capacity specified by the output control command value Pg * is reduced, The electric power generated by the solar cell panel 2 is stored, and the electric power charged in the storage battery 3 is discharged after the power generation operation of the solar cell panel 2 is completed. That is, the power conditioner 1 according to the first embodiment sends most of the power generated with the maximum efficiency to the commercial power source SPS regardless of the amount of power that can be sent specified by the output control command value Pg *. To do.

  From the above description, in the power conditioner 1 according to the first embodiment, the difference between the converter control unit 21 and the sendable power designated from the outside by the converter control unit 21 and the generated power Ppv of the solar cell panel 2 is Absorbs by charge / discharge operation. In addition, the power conditioner 1 according to the first exemplary embodiment has the maximum power so that the output power asymptotically approaches the transmittable power specified by the output control command value Pg * while generating the solar panel 2 with maximum efficiency. The point tracking control unit 13 is controlled. As a result, the power conditioner 1 according to the first exemplary embodiment supplies most of the electric power generated with the maximum efficiency to the commercial power source SPS regardless of the amount of power that can be sent specified by the output control command value Pg *. Can be sent out.

  In recent years, operators operating commercial power supplies SPS may require output control for stable operation of the power grid. When such output control is required, the power generation capability of the solar cell panel 2 is suppressed. There is a problem that the power that can be generated originally has to be wasted. Therefore, as in the power conditioner 1 according to the first embodiment, regardless of whether there is an output restriction, the effect that most of the generated power generated with the maximum efficiency can be sent to the commercial power source SPS is great.

  Further, in the maximum power follow-up function described in Patent Document 2, since only control of the transmission power based on the output characteristics of the generated power Ppv is performed, if the current applied to the inverter changes due to charging / discharging of the storage battery 3, the control is defective. May occur. However, according to the power conditioner 1 concerning Embodiment 1, the malfunction resulting from the charging / discharging operation | movement of the storage battery 3 does not arise.

  In the power conditioner 1 according to the first embodiment, by providing the backflow prevention diode 12, the storage battery 3 is charged by the current flowing from the commercial power source SPS, and the current charged in the storage battery 3 flows again to the commercial power source SPS. You can guarantee that you will not miss it. As a result, the operator operating the commercial power supply SPS prohibits the re-transmission of the supplied power to the commercial power supply SPS. Even if the storage battery 3 is installed by providing the backflow prevention diode 12, the power is not supplied. It is important to ensure that it is not retransmitted.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Power conditioner 2 Solar cell panel 3 Storage battery 11, 12 Backflow prevention diode 13 Maximum power point tracking control unit 14 Unidirectional DC / AC converter 15 Unidirectional DC / DC converter 16 Inverter 21 Converter control unit 22 Bidirectional DC / DC converter 31, 33 Current detection unit 32, 34 Voltage detection unit 41 Generated power calculation unit 42 Low pass filter 43 Divider 44 Adder 45 Multiplier 51 PWM control unit 52 DC / DC converter N1 Branch point W1 DC bus W2 Branch DC bus SPS Commercial Power supply Ipv Generated current Vi Generated voltage Io Sending current Vo Sending voltage Is Charge / discharge current Is * Charge / discharge current command value Isps * Sending current command value Pg * Output control command value Ppv Generated power M Charge / discharge coefficient

Claims (5)

A direct current bus for transmitting the generated power generated by the solar panel;
A branch DC bus branched from a branch point provided on the DC bus;
A converter control unit that generates a charge / discharge current command value by detecting a generated current and a generated voltage from the DC bus closer to the solar cell panel than the branch point;
A bidirectional DC / DC converter that is provided between the branch DC bus and the power storage device, and charges and discharges the power storage device with a current amount according to the charge / discharge current command value;
A unidirectional DC / AC converter that converts a sending DC power given from the DC bus into a sending AC power given to a system power supply based on a sending current command value;
A maximum power point follow-up control unit that detects a transmission current and a transmission voltage from the DC bus closer to the unidirectional DC / DC converter than the branch point and generates the transmission current command value;
The converter control unit calculates surplus power or insufficient power of the generated power with respect to the sendable power based on the sendable power specified by an output control command value given from the outside and the generated power, and the surplus power Generating the charge / discharge current command value that causes the power storage device to charge / discharge with electric power or a current amount corresponding to the insufficient power;
The maximum power point tracking control unit receives the output control command value and sets the voltage of the DC bus to a voltage that maximizes the generated power in a state independent of the sendable power, and the generated power is When the transmitted AC power is larger than the transmittable power, the transmitted AC command value is generated so that the transmitted AC power is equal to or lower than the transmittable power, and when the generated power is smaller than the transmittable power, the transmitted AC power is The power conditioner which produces | generates the said sending electric current command value so that it may become below the power which can be sent out and above the said generated electric power. The converter control unit is a generated power calculation unit that calculates the generated power based on the generated current and the generated voltage;
A power ratio calculation unit that calculates a power ratio indicating a ratio between the sendable power and the generated power;
A charge / discharge coefficient calculation unit that calculates a charge / discharge coefficient by subtracting 1 from the power ratio;
The power conditioner according to claim 1, further comprising: a charge / discharge current command value calculation unit that outputs a product of the generated current and the charge / discharge coefficient as the charge / discharge current command value.   The maximum power point tracking control unit calculates a bus voltage at which the generated power is maximized based on a preset output characteristic of the solar battery panel, and is equal to or less than the sendable power with respect to the bus voltage and the send The power conditioner according to claim 1 or 2, wherein the transmission current command value is calculated so that the transmission AC power is asymptotic to possible power.   The backflow prevention part which prevents the inflow of the electric current from the said system power supply to the said electrical storage apparatus is provided on the said DC bus near the said unidirectional DC / DC converter rather than the said branch point from the said branch point. The power conditioner of Claim 1. A direct current bus for transmitting the generated power generated by the solar panel;
A branch DC bus branched from a branch point provided on the DC bus;
A bidirectional DC / DC converter that is provided between the branch DC bus and the power storage device, and charges and discharges the power storage device with a current amount corresponding to a charge / discharge current command value;
A unidirectional DC / AC converter that converts a sending DC power given from the DC bus based on a sending current command value into a sending AC power given to a system power supply, and a sending power control method for a power conditioner,
Based on the transmittable power specified by the output control command value given from the outside and the generated power, the surplus power or the insufficient power of the generated power with respect to the transmittable power is calculated, and the surplus power or the insufficient power is calculated. Calculate the charge / discharge current command value based on the corresponding current amount,
In response to the output control command value, the voltage of the DC bus is set to a voltage at which the generated power is maximized in a state independent of the sendable power, and when the generated power is larger than the sendable power, the When the transmission AC power is equal to or less than the transmittable power and the generated power is smaller than the transmittable power, the transmission current command value is calculated such that the transmission AC power is equal to or less than the transmittable power and equal to or greater than the generated power. The power transmission control method for the inverter.

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