JP5957652B2 - Power conversion system - Google Patents

Description

  The present invention relates to a power conversion system that converts power generated by a generator into AC power and supplies the AC power to a plurality of consumers.

  Conventionally, a power conversion system that distributes generated power of a common generator (for example, a solar cell, a fuel cell, a wind power generator, etc.) to a plurality of consumers at a predetermined distribution ratio has been proposed (Patent Document 1). .

JP 2003-134672 A

  Such a power conversion system is, for example, a distribution that is determined in advance according to the investment ratio or the like when it is desired to provide a common generator in an apartment house, or when a plurality of neighboring customers want to provide a common generator. The generator was used using the ratio.

  This power conversion system includes a solar cell as a generator, and converts the generated power of the solar cell into AC power by an inverter circuit. The converted AC power is distributed to each consumer using a branch wiring that branches from the output side of the inverter circuit. Each branch line connected to each consumer is provided with a power controller, and when distributing power, the power controller controls on / off of the power flowing through the branch line to each customer. The power of the above-described distribution ratio is distributed. Thus, when distributing electric power to each consumer using a branch wiring, since an inverter circuit can also be shared, an apparatus can be comprised cheaply.

  However, when power is distributed to each consumer using a branch wiring that branches from the output side of the inverter circuit as in a conventional power conversion system, even if the load used by the consumer varies slightly. Since the electric power supplied to the consumer fluctuates, it is difficult to distribute the electric power to the consumer at a predetermined distribution ratio, and there is a possibility that unfairness may occur in the electric power distribution.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a power conversion system that can suppress unfairness caused by power distribution while configuring the system at a low cost.

  In order to achieve the above object, the present invention includes an inverter circuit that converts DC power into AC power, and a branch wiring that branches the output side of the inverter circuit, to a plurality of consumers that receive power supply from a commercial power system. In the power conversion system that distributes the AC power via each branch line, the power conversion system includes a power detection circuit that detects a supply power amount for a predetermined period supplied to each branch line connected to the consumer, When the ratio of the amount of power to be distributed to the branch wiring is configured to be settable, and the ratio of the amount of supplied power detected by the power detection circuit is different from the ratio of the amount of power to be distributed to the branch wiring, each demand A power conversion system characterized by notifying a house of an excessive or insufficient amount of power.

  According to the present invention, power is distributed to each consumer using a branch wiring, and AC power is supplied to a plurality of consumers using an inexpensive configuration that shares an inverter circuit. Moreover, since each consumer can grasp | ascertain the electric energy which is excessive and insufficient, the electric bill of the electric energy can be settled later. Thereby, it is possible to suppress unfairness caused by power distribution while configuring the system at a low cost.

  Further, in the above-described invention, the amount of sold power that flows backward from each consumer to the commercial power system is detected, and consumed by each of the supplied power based on the supplied power amount and the sold power amount. 2. The power conversion system according to claim 1, wherein the amount of consumed power is obtained, and each consumer is notified of the amount of power that is excessive or insufficient for each of the amount of consumed power and the amount of power sold.

  Further, in the above-mentioned invention, the unit price of the commercial power grid and the unit price of the commercial power grid are input, and the power consumption is calculated using the unit price of the power grid. An excess or deficiency of electricity charges is informed by the ratio, and the electricity sales amount is informed of an excess or deficiency of electricity charges by the ratio using the unit price of the power sale charges.

  Further, in the above-described invention, the unit price of the electricity charge for the excess or deficient electric energy can be set, and the ratio of the electric energy supplied to each customer detected by the electric power detection circuit is distributed to the branch wiring. If it is different from the ratio of the amount of electric power to be used, it is characterized by notifying each consumer of the electric charge of the electric power amount that is excessive or insufficient using the set unit price of the electric charge.

  ADVANTAGE OF THE INVENTION According to this invention, the power conversion system which can suppress the unfair at the time of the distribution of electric power can be provided, comprising a system cheaply.

It is a schematic diagram showing a power conversion system. It is a schematic diagram showing a consumer. It is a figure which shows a display monitor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a power conversion system 2. As shown in this figure, each consumer 3a, 3b is supplied with AC power from the commercial power system 4, and a common power conversion system 2 is provided for these consumers 3a, 3b.

  In the power conversion system 2, a common solar cell 1 (generator) is connected to the consumers 3a and 3b. In the present embodiment, the consumers 3a and 3b are constituted by detached houses, and the consumers 3a and 3b are neighboring houses, respectively. For example, it is installed in the consumer 3a. The solar cell 1 is disposed on the roof of the consumer 3a, and the power conversion system 2 is disposed beside the first floor (the consumer 3a) of the building. The generated power of the solar cell 1 is input to the power conversion system 2, and the power conversion system 2 distributes and supplies this generated power to the respective consumers 3a and 3b. The consumers 3a and 3b are not limited to neighboring single-family houses, and may be constituted by apartment houses such as apartments and apartments.

  FIG. 2 is a schematic diagram showing a consumer. Since the customers 3a and 3b have the same configuration, they will be described as the customer 3. As shown in this figure, the customer 3 has a distribution board 31. The distribution board 31 inputs AC power supplied from the commercial power system 4 and AC power supplied from the power conversion system. The input power is superimposed and supplied to the load 35 of the consumer 3. .

  In addition, a power purchase meter 32 and a power sale meter 33 are respectively provided on the commercial power grid 4 side of the distribution board 31 of each consumer 3. The electricity purchase meter 32 detects the amount of power supplied from the commercial power system 4 to the consumer 3. The detected amount of electric power (the amount of electric power purchased) is used to calculate the electric power purchased electric charge. The electricity sales meter 33 detects the amount of electric power supplied from the consumers 3a, 3b to the commercial power system 4. The detected power amount (power sale power amount) is used to calculate a power sale power charge.

  Thus, each consumer 3a, 3b is individually provided with the distribution board 32 and the power sale meter 33, and is configured to be able to individually buy and sell power with the power company.

  Each of the consumers 2a and 2b is provided with a display monitor 34 so that the usage status of the power of the consumers 2a and 2b can be displayed.

  Next, the power conversion system 2 will be described in detail. As shown in FIG. 1, the power conversion system 2 includes a booster circuit 21, an inverter circuit 22, an interconnection relay 23 (switch), a control circuit 24, and output current sensors 25a and 25b. Further, the booster circuit 21, the inverter circuit 22, the interconnection relay 23, the control circuit 24, the input current sensor 51, and the output current sensors 25a and 25b are housed in a common housing, and a common housing is provided by arranging this housing. It is put together in the place (here the customer 2c).

  The booster circuit 21 is connected between the solar cell 1 and the inverter circuit 22 and boosts the voltage of the solar cell 1. The booster circuit 21 includes a reactor, a switching element such as IGBT or FET, a diode circuit, and a capacitor. Specifically, the reactor and the diode are connected in series to form a series circuit, and the reactor side of the series circuit is connected to the positive electrode side of the solar cell 1. Moreover, the connection point of a reactor and a diode and the negative electrode side of a solar cell are connected via the switch element. Moreover, the diode side of the series circuit and the negative electrode side of the solar cell are connected via a capacitor. The booster circuit 21 periodically conducts / cuts off the switch element. For example, by setting a ratio (hereinafter referred to as ON ratio) for conducting the switch element for each period, the voltage of the solar cell is set at a desired boost ratio. Boost and output to both ends of the capacitor.

  The inverter circuit 22 converts the generated power of the solar cell 3 input through the booster circuit 21 into AC power. Further, branch lines La and Lb branching from the output side of the inverter circuit 22 are connected to the output side of the inverter circuit 12, and the respective consumers 3a and 3b are connected to the respective consumers 3a and 3b via the branch lines. Distributes the AC power to be output.

  The inverter circuit 22 has a bridge circuit composed of four switch elements such as IGBTs and FETs, and a filter circuit composed of two reactors and a capacitor. In the bridge circuit of the inverter circuit 22, the DC side is connected to both ends of the capacitor of the booster circuit, and the AC side is connected to the filter circuit. In the filter circuit, one end of each of the two reactors is connected by a capacitor, and the other end of each of the reactors is connected to the AC side of the bridge circuit. The inverter circuit 22 uses a predetermined PWM (Pulse Width Modulation) signal to conduct / cut off the four switch elements, thereby generating AC power having a waveform synchronized with the commercial power system and supplying it to the consumers 3a and 3b. To do.

  The interconnection relay 23 is interposed in the branch lines La and Lb, respectively, and connects / releases the lines of the branch lines La and Lb. As a result, when the interconnection relay 23 is connected, the AC power output from the inverter circuit 22 is supplied to the consumers 2a and 2b, and when the interconnection relay 23 is opened, the consumers 3a and 3b are supplied. The AC power output from the supplied inverter circuit 22 is cut off.

  The branch lines La and Lb are provided with output current sensors 53a and 53b, respectively, which detect instantaneous output currents Ioa and Iob of the branch lines La and Lb. The detected output currents Ioa and Iob are input to the control circuit, and the execution values (or average values) are output in the control circuit 14 using the output currents Ioa and Iob and the output voltages Voa and Vob input in the past. Calculated. Hereinafter, the effective values of the output currents Ioa and Iob are referred to as output currents Ia and Ib. The output currents Ia and Ib are used for controlling the operation of the power conversion system 11 and the like.

  The control circuit 24 is composed of, for example, a microcomputer, and controls the operation of the booster circuit 21, the operation of the inverter circuit 22, and the operation of the interconnection relay 23.

The control circuit 24 controls the ON ratio of the booster circuit 21 so that the generated power of the solar cell 1 (input power to the booster circuit 21) is maximized. Specifically, the generated power of the solar cell 1 input to the booster circuit 21 is calculated from the input current and the input voltage obtained from the input current sensor 51 and the input voltage sensor 52. If the calculated generated power is greater than the previously calculated generated power, change the ON ratio to the same one that changed the previous ON ratio (lower the previous ON ratio, lower it again, and increase the previous ON ratio) If you do, increase it). Conversely, if the generated power is smaller than the previously calculated power, change the ON ratio to the opposite of the previous ON ratio change (the higher the previous ON ratio, the higher the previous ON ratio) If so, lower).

  The control circuit 24 generates a PWM signal for turning on / off the switch element of the inverter circuit 22. Specifically, the control circuit 24 calculates the output current command value It of the inverter circuit 12 and simplifies the description by assuming that the commercial system voltage supplied to each consumer is the same, and detects the detected output current ( A PWM signal that outputs the output voltage of the inverter circuit 22 is generated so that Ia + Ib) matches the output current command value.

  The control circuit 24 generates a signal for connecting / releasing the interconnection relay 23 and controls the interconnection relay 23 to be in a desired state (connection state or open state). For example, when the solar cell 1 becomes capable of generating power, the interconnection relay 23 is set in a connected state, and when the solar cell 1 becomes incapable of generating power, the interconnection relay 23 is opened. The solar cell 1 and the commercial power system are separated.

  The control circuit 24 receives and stores the ratio of the amount of power to be distributed to the plurality of branch lines La and Lb by an input unit (not shown). Based on the output currents Ia and Ib detected by the output current sensors 25a and 25b, the control circuit 24 supplies power for a predetermined period supplied to the branch wirings La and Lb connected to the consumers 3a and 3b. Is detected. That is, the control circuit 24 functions as a power detection circuit that detects the amount of power supplied from the inverter circuit 22 to each consumer 3a, 3b. The power supply amount can be obtained by integrating the sampling time T and the voltage V of the commercial power system with the integrated value of the output currents Ia and Ib. For example, the power supply amount Pa of the consumer 3a can be obtained by Pa = ΣIa × V × T. In the case of the customer 3b, the symbol a only changes to b.

  The control circuit 24 has a communication function for communicating with the display monitor 34 of the consumer 3, and the ratio of the detected power supply amount is the amount of power to be distributed to the stored branch wirings La and Lb. When it is different from the ratio, the consumers 3a and 3b are informed of the excess and deficient amount of power (send and drop information to the display monitor).

Specifically, the control circuit 24 has a communication function for communicating with the power sale meter 33, and receives the amount of sold power that flows backward from each consumer 3a, 3b to the commercial power system 4. The amount of power sold may be obtained by detecting a reverse flow current by providing a current sensor between the commercial power system 4 and the distribution board 3. Alternatively, the power sale power amount detected by the power sale meter 33 may be stored in the display monitor 34, and the power sale power amount may be received via the display monitor.

  And the control circuit 24 calculates | requires the power consumption amount consumed by each consumer 3a, 3b among the supply power amount based on the supply power amount and the power sale power amount, and each power consumption amount and each power sale power amount Inform each consumer 3a, 3b of the amount of electric power that is excessive or insufficient (send information on the electric energy that is excessive or insufficient to the display monitor). Of the amount of power supplied, the amount of power consumed by each consumer 3a, 3b can be determined from the difference between the amount of power supplied and the amount of power sold.

  In addition, the control circuit 24 informs each consumer 3a, 3b of the electric charge of the electric power amount that is excessive or insufficient (sends information on the electric charge of the electric energy that is excessive or insufficient to the display monitor). An excess or deficiency of electricity charges is also determined for each of the consumed power amount and the sold power amount consumed by each of the consumers 3a and 3b.

The electricity charges Mxa and Mxb that are excessive and insufficient for each of the consumers 3a and 3b with respect to the amount of power consumed by each of the consumers 3a and 3b can be obtained as follows.
(1) Mxa = {(Pua + Pub) × r1−Pua} × M1
(2) Mxb = {(Pua + Pub) × r2−Pub} × M1
However, the amount of power consumed by each consumer 3a, 3b out of the amount of power supplied is distributed to Pua, Pub, each customer 3a, 3b (the distribution ratio of the power to branch wires La, Lb) The distribution ratio is r1, r2 (where r1 + r2 = 1), and the unit price of purchased electricity is M1.

The electricity charges Mya and Myb that are excessive and insufficient for each customer 3a and 3b with respect to the amount of electric power sold by each customer 3a and 3b can be obtained as follows.
(3) Mya = {(Pba + Pbb) × r1−Pba} × M2
(4) Myb = {(Pba + Pbb) × r2−Pbb} × M2
However, the electric power sales amount of each consumer 3a, 3b is set to Pba, Pbb, and the unit price of the electric charge of the electric power sales power is set to M2. The unit price of the power purchase fee of the commercial power system 4 and the unit price of the power sale fee of the commercial power amount rectangle 4 etc. can be obtained (input) via the Internet by connecting the control circuit 24 to the Internet. .

  Information on the excess and deficiency of the power amount and the power rate calculated in this way is transmitted from the control circuit to the display monitor 34 of each consumer 3a, 3b. FIG. 3 is a diagram showing a display monitor. As shown in the figure, the display monitor 34 is divided into power consumption amount consumed by each consumer 3a, 3b and power sale power amount of the supplied power amount, and the excess or deficiency of the power amount and the power charge amount, respectively. Excess or deficiency is indicated.

  Further, here, the excess or deficiency of the electric energy is shown as a bar graph so that it can be easily understood visually. On the bar graph, the amount of electric power when distributed according to the ratios r1 and r2 of the amount of electric power to be distributed to the branch wirings La and Lb (indicated by the inverted triangle) is shown, and the bar graph exceeds this mark. If the bar graph does not exceed this mark, it can be seen that there is an insufficient amount of power.

  In addition, the amount of power shortage is displayed by a dotted line, the actual power amount is displayed by a solid line, and the excessive amount of power is displayed by hatching, so that the display methods are different.

  In addition, on the right side of the bar graph, the excess or deficiency of the electricity rate due to the excess or deficiency of the electric energy is displayed. For example, it is easy to understand if the amount is shown directly in numbers. Moreover, as shown in FIG. 3, the total of the excess and deficiency of the electric power charge of electric power consumption and electric power sales electric power amount is described.

  As described above, according to the present embodiment, power is distributed to the consumers 3a and 3b using the branch wirings La and Lb, and the plurality of consumers 3a is used using an inexpensive configuration that shares the inverter circuit 22. AC power was supplied to 3b. Moreover, since each consumer 3a, 3b can grasp | ascertain the electric energy which is excess and deficient, the electric bill of the electric energy can be settled later. Thereby, it is possible to suppress unfairness caused by power distribution while configuring the system at a low cost.

  In addition, according to the present embodiment, the amount of power consumed by each consumer 3a, 3b in the amount of power supplied is obtained, and each customer 3a, 3b is excessive for each amount of power consumed and sold. The amount of electric power to be deficient was obtained, and the electricity charges that were inadequate due to the amount of electric power were informed to the consumers 3a and 3b. Thereby, it is possible to suppress unfairness that occurs when the unit price of the purchased electricity and the unit price of the selling power are different when the electricity rate is settled. There are the following reasons for this.

  If there is an excess or deficiency in the amount of power consumed within the consumer, it will be necessary to purchase extra power from the commercial power grid 4 or make up for it without purchasing power from the commercial power grid 4. It would be desirable to liquidate with purchased electricity. In addition, when an excess or deficiency in the amount of electric power sold occurs, extra power is sold or sold to the commercial power system 4, so that it is desirable to liquidate with the electric power sold. Here, in the case where the power purchase fee and the power sale fee are different from each other, unfairness will occur in any of the consumers unless the liquidation is made at the respective rates.

  As mentioned above, although one Embodiment of this invention was described, the above description is for making an understanding of this invention easy, and does not limit this invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof.

  For example, in the present embodiment, the solar cells 1 installed at one place are used as a common generator. For example, the solar cells 1 are provided in a plurality of houses, and the generated power of these solar cells 1 is used. It can be seen that a common generator is also used when the generated power of the solar cell 1 collected by the power system 2 is distributed by the inverter circuit 22.

  For example, in this embodiment, although the solar cell 1 was used as a generator, various generators, such as a fuel cell, a storage battery, a wind power generator, and an engine generator, can be used.

  In addition, for example, in this embodiment, the consumption consumed by each consumer in the amount of supplied power by using information on the unit price of the commercial power grid and the unit price of the commercial power grid Electricity charges that are excessive or insufficient for each amount of electric power and electric power sold are informed. However, if there is a unit price for an electric charge that can be agreed upon between the consumers, the unit price of the electric charge You may use the unit price.

In this case, it is preferable that the unit price of the electricity bill for the excess or deficient amount of power can be set. And when the ratio of the amount of power supplied to each consumer is different from the ratio of the amount of power to be distributed to the branch lines La and Lb, each consumer 3a and 3b is over and under using the unit price of the set electricity rate. It is good to inform the electricity bill of the amount of electricity.

DESCRIPTION OF SYMBOLS 1 Solar cell 2 Power conversion system 3 Consumer 4 Commercial power system 21 Booster circuit 22 Inverter circuit 23 Relay 24 Control circuit 25 Output current sensor 31 Distribution board 32 Electricity meter 33 Electric power meter 34 Display monitor 35 Load

Claims (2)

An inverter circuit that converts direct current power into alternating current power; and a branch wiring that branches the output side of the inverter circuit, and each of the alternating current via the branch wiring to a plurality of consumers that are supplied with power from a commercial power system In a power conversion system that distributes power,
A power detection circuit for detecting a power supply amount for a predetermined period supplied to each branch wiring connected to the consumer;
The ratio of the amount of power to be distributed to the plurality of branch wirings is configured to be settable,
When the ratio of the amount of supplied power detected by the power detection circuit is different from the ratio of the amount of power to be distributed to the branch wiring, the power conversion system is configured to notify each consumer of the amount of power that is excessive or insufficient. The unit price of the electricity charge of the excess or deficient amount of power is configured to be settable,
When the ratio of the amount of power supplied to each consumer detected by the power detection circuit is different from the ratio of the amount of power to be distributed to the branch wiring, each consumer is excessively charged using the unit price of the set electricity rate. The power conversion system according to claim 1, wherein an electricity bill for an insufficient amount of electric power is notified.

Images