JP2012222908A - Power conditioner, power control system, and power control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control power to be sold and power to be purchased to be constant, thereby protecting a power system from a bad effect of using a natural energy generating apparatus to generate the power to be sold and to be purchased.SOLUTION: A hybrid power conditioner 100 which converts power generated by a solar battery 10 and power discharged from a storage battery 20 to AC and outputs the power to a power system 2 and a load 40 is provided with a controller 140 which sets an AC command value regarding input and output AC power of the hybrid power conditioner 100 and controls charging and discharging by the storage battery 20. The controller 140 sets, in an operation mode for controlling the power to be sold and to be purchased to be constant, the AC command value so as to make the power to be sold and to be purchased constant, on the basis of measured values of power consumed by the load 40, and controls the charging and discharging by the storage battery 20 to make the input and output AC power become the AC command value.

Description

  The present invention relates to a power conversion device, a power control system, and a power control method that use a power generator that generates natural energy.

  With the widespread use of power generation devices that generate natural energy such as sunlight and wind power (hereinafter referred to as “natural energy power generation devices” as appropriate), the power generated by the natural energy power generation devices is converted into alternating current (AC). Thus, power converters having a function of outputting to a load and a power system are widely used.

  Moreover, for a power control system that uses a storage battery together with a natural energy power generation device, a hybrid type that has not only the above-described function but also a function of converting alternating current power from a power system into direct current (DC) and outputting it to the storage battery. A power converter (hybrid power conditioner) has been put into practical use.

  By introducing a hybrid power converter, the storage battery is charged with midnight power from the power system, and the power is discharged for daytime load consumption, or the storage battery is used as an emergency power source during a power failure It can be used as a stand-alone operation.

  At present, the hybrid type power conversion device is for pursuing the convenience of the user under the current system such as low midnight power charges.

  On the other hand, unlike a natural energy power generation device, in a power control system using a power generation device composed of a gas engine, a turbine or the like, power to be input / output (power purchase) (hereinafter referred to as “power purchase power purchase”). In order to control the power generation amount of the power generation device so as to be controlled to a constant value, a technique is known (see Patent Documents 1 to 3).

JP-A-11-69634 JP 2002-27669 A JP 2005-229710 A

  In the future, natural energy power generation equipment is expected to spread rapidly, and the amount of power generated by natural energy power generation equipment is left to the right. Therefore, the capital investment cost for maintaining power quality on the power system side is large. It will be a challenge.

  Therefore, even when a natural energy power generation device is used, it is desired to realize a technique that does not adversely affect the power system by controlling the purchased power to be a constant value.

  Here, the technologies described in Patent Documents 1 to 3 are based on the premise that the power generation amount of the power generation device is controllable, and in a power control system using a natural energy power generation device whose power generation amount is difficult to control. There was a problem that could not be applied.

  Therefore, the present invention provides a power conversion device, a power control system, and a power control that do not adversely affect the power system by controlling the purchased power to be constant even when a natural energy power generation device is used. It aims to provide a method.

  In order to solve the above-described problems, the present invention has the following features.

  A feature of the power conversion device according to the present invention is that power obtained by power generation of the power generation device (solar cell 10) and discharge of the storage battery (storage battery 20) is converted into alternating current to convert the power system (power system 2) and load (load 40). ) And a function of converting alternating current power from the power system into direct current and outputting it to the storage battery (hybrid power conditioner 100). A command value setting unit (controller 140) for setting a command value for device input / output power, which is AC power to be input / output, and a charge / discharge control unit (controller 140) for controlling charge / discharge of the storage battery. The value setting unit, in the operation mode for controlling the power selling power purchased and AC power input and output to and from the power system to a constant value, the measured value of the power consumption of the load and Alternatively, based on the measured value of the power sale power purchase power, the command value is set so that the power sale power purchase power becomes the constant value, and the charge / discharge control unit is configured to use the command value by the command value setting unit. Is set, the charging / discharging of the storage battery is controlled so that the device input / output power becomes the command value.

  In the above feature, the charge / discharge control unit is configured such that the command value is set by the command value setting unit, and a charge level of the storage battery is set lower than an upper limit threshold indicating overcharge. The charging / discharging of the storage battery may be limited while controlling the charging / discharging of the storage battery so that the device input / output power becomes a value according to the command value when the threshold value of the storage battery is exceeded.

  In the above feature, when the command value is set by the command value setting unit and when the charge level of the storage battery exceeds the first threshold value, control is performed to suppress power generation of the power generation device. A power generation suppressing unit may be further provided.

  In the above feature, the charge / discharge control unit is configured such that the command value is set by the command value setting unit, and the charge level of the storage battery is set higher than a lower limit threshold indicating overdischarge. The discharge of the storage battery may be limited while controlling the charge / discharge of the storage battery so that the input / output power of the device becomes a value according to the command value when the threshold value is below the threshold value.

  The power control system according to the present invention is characterized in that a power generation device (solar cell 10), a storage battery (storage battery 20), and power generated by the power generation of the power generation device and discharge of the storage battery are converted into alternating current to be converted into an electric power system ( Power converter (hybrid power conditioner) having a function of outputting to power system 2) and a load (load 40) and a function of converting AC power from the power system into DC and outputting it to the storage battery 100), and a power measuring unit (power sensor 60) that measures the power consumption of the load and / or the power selling power that is AC power input and output to and from the power system; A command value setting unit (controller 140, power management device 200, or game machine) for setting a command value for device input / output power that is AC power input / output by the power converter. Way device 300) and a charge / discharge control unit (controller 140) that controls charging / discharging of the storage battery, wherein the command value setting unit is an operation mode for controlling the power selling / purchasing power to a constant value. And setting the command value so that the purchased power for electric power sale becomes the constant value based on the measurement value obtained by the power measurement unit, and the charge / discharge control unit is configured to execute the command by the command value setting unit. The gist is to control charging and discharging of the storage battery so that the device input / output power becomes the command value when a value is set.

  The power control method according to the present invention is characterized in that the power obtained by the power generation of the power generation device and the discharge of the storage battery is converted to alternating current and output to the power system and the load, and the alternating current power from the power system is converted to direct current. A power control method for a power conversion device having a function of converting to a storage battery and outputting to the storage battery, for controlling the power purchase power to be a constant value, which is AC power input to and output from the power system. In the operation mode, based on the measured value of the power consumption of the load and / or the measured value of the purchased power for power sale, the power conversion device inputs / outputs the purchased power for power sale to the constant value. Step A (step S12) for setting a command value for device input / output power that is AC power, and control of charge / discharge of the storage battery so that the device input / output power becomes the command value set in step A Craft B (step S13), and summarized in that including.

  Advantageous Effects of Invention According to the present invention, even when a natural energy power generation device is used, a power conversion device, a power control system, and power control that do not adversely affect the power system by controlling the purchased power for sale to a constant value. Can provide a method.

1 is an overall configuration diagram of a power control system according to a first embodiment. It is a figure for demonstrating schematic operation | movement of the electric power control system which concerns on 1st Embodiment. It is a flowchart of the electric power control method which concerns on 1st Embodiment. It is a figure for demonstrating the application example of 1st Embodiment. It is a whole block diagram of the electric power control system which concerns on 2nd Embodiment. It is a whole block diagram of the electric power control system which concerns on other embodiment. It is a whole block diagram of the electric power control system which concerns on other embodiment.

  A first embodiment, a second embodiment, and other embodiments of the present invention will be described with reference to the drawings. In the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

[First Embodiment]
FIG. 1 is an overall configuration diagram of a power control system according to the present embodiment. In the following drawings, power lines are indicated by bold lines, and control signal lines are indicated by broken lines.

  As shown in FIG. 1, the power control system according to the present embodiment includes a solar battery 10 that receives sunlight to generate power, a storage battery 20 that stores power, a hybrid power conditioner 100 that mainly converts power, It has the switchboard 50 which distributes electric power, and the load (for example, household appliances) 40 which consumes electric power.

  In the present embodiment, the hybrid power conditioner 100 converts the power obtained by the power generation of the solar cell 10 and the discharge of the storage battery 20 into AC and outputs it to the power system 2 and the load 40. A function of converting the AC power into DC and outputting the same to the storage battery 20. The solar cell 10 corresponds to a power generation device (natural energy power generation device), and the hybrid power conditioner 100 corresponds to a power conversion device.

  Solar cell 10, storage battery 20, hybrid power conditioner 100, switchboard 50, and load 40 are provided in customer 1 that receives power supply from power system 2 of the power company. In addition, the solar cell 10 may be comprised by one solar cell panel, and may be comprised by the several solar cell panel. Further, the load 40 may be one or plural.

  Between the solar cell 10 and the hybrid power conditioner 100, a power line L1 for transmitting DC power obtained by the power generation of the solar cell 10 to the hybrid power conditioner 100 is provided. Between the storage battery 20 and the hybrid power conditioner 100, DC power for charging the storage battery 20 is transmitted to the storage battery 20, and DC power obtained by discharging the storage battery 20 is transmitted to the hybrid power conditioner 100. A power line L2 is provided.

  Further, between the hybrid power conditioner 100 and the switchboard 50, AC power output from the hybrid power conditioner 100 (hereinafter referred to as “AC output power”) is transmitted to the switchboard 50, and from the power system 2. A power line L <b> 3 for transmitting the received (purchased) AC power to the hybrid power conditioner 100 is provided. Between the switchboard 50 and the load 40, a power line L4 for transmitting the AC output power of the hybrid power conditioner 100 and the AC power received from the power system 2 to the load 40 is provided. Between the switchboard 50 and the power grid 2, a power line L5 for transmitting the AC output power of the hybrid power conditioner 100 to the power grid 2 and for transmitting AC power received from the power grid 2 to the switchboard 50. Is provided.

  When the AC output power of the hybrid power conditioner 100 is less than the power consumption of the load 40, the switchboard 50 receives the shortage of AC power from the power system 2, and the AC output power of the hybrid power conditioner 100 and the power system AC power received from 2 is supplied to the load 40. The distribution board 50 is configured to transmit (sell) the excess AC power to the power system 2 when the AC output power of the hybrid power conditioner 100 exceeds the power consumption of the load 40.

  In the present embodiment, the switchboard 50 includes a power sensor 60 provided on the power line L4. The power sensor 60 measures the power consumption of the load 40 and corresponds to a power measuring unit.

  The hybrid power conditioner 100 includes a DC / DC converter 110, a DC / DC converter 120, a DC / AC converter 130, and a controller 140. Note that a user interface unit that receives input from the user may be connected to the controller 140 by wire or wirelessly.

  The DC / DC converter 110 is connected to the power line L1, and DC / DC converts DC power input through the power line L1 and outputs the DC power. The DC / DC converter 120 is connected to the power line L2, and has a function of performing DC / DC conversion on DC power input via the power line L2, and a DC output from the DC / DC converter 110. The power and the DC power output from the DC / AC converter 130 are DC / DC converted and output via the power line L2. The DC / AC converter 130 converts the DC power output from each of the DC / DC converter 110 and the DC / DC converter 120 into AC and outputs the AC power via the power line L3, and the power line L3. A function of converting the input AC power into DC and outputting the DC power.

  Note that each of the DC / DC converter 110, the DC / DC converter 120, and the DC / AC converter 130 has a built-in power sensor, and is configured to output a measured value of the power sensor to the controller 140. Has been.

  The controller 140 controls various functions of the hybrid power conditioner 100 and charging / discharging of the storage battery 20, and is constituted by a CPU and a memory. In the present embodiment, the controller 140 corresponds to a command value setting unit and a charge / discharge control unit.

  Specifically, the controller 140 receives power measurement values from the DC / DC converter 110, the DC / DC converter 120, the DC / AC converter 130, and the power sensor 60, and the DC / DC converter 110. The control signal is output to the DC / DC converter 120, the DC / AC converter 130, and the storage battery 20. The controller 140 may have a communication interface and be configured to be able to communicate with a network.

  The operation of the power control system configured as described above will be described below. FIG. 2 is a diagram for explaining a schematic operation of the power control system according to the present embodiment.

As shown in FIG. 2, the power generated by the solar battery 10 is generated power “PV”, the power discharged by the storage battery 20 (or power charging the storage battery 20) is charged / discharged power “BT”, and the hybrid power conditioner 100 If the output power is AC output power “AC”,
PV + BT = AC (1)
The relationship holds.

  If you specify two of these three, the remaining one will be determined as a result. Therefore, when the system is controlled for some purpose, it is important to determine which of these three elements has priority (priority order).

  A general method is a method of setting a command value for the charge level of the storage battery 20 and controlling the charge level of the storage battery 20 to be the command value. Since the amount of power generation (generated power) of the solar cell 10 depends on the amount of solar radiation, the AC output power of the hybrid power conditioner 100 is a consequence.

Here, the power selling / purchasing power input / output (power selling / purchasing) with the power system 2 is defined as positive power flowing into the load 40,
Purchased electricity for sale = Load-AC = Load-PV-BT (2)
It becomes.

  That is, the purchased power for power sale is not only affected by the change in the generated power due to the solar radiation state but also affected by the change in the power consumption of the load 40. Of course, by changing the command value for the charge level of the storage battery 20 each time, it is possible to stabilize the power selling / purchasing power, but it is difficult to quickly follow each change.

  On the other hand, in the present embodiment, the controller 140 sets a command value for the AC output power “AC” of the hybrid power conditioner 100, and sells it according to an operation mode for controlling the AC output power to be the command value. The electric power purchased power is controlled to a constant value (electric power purchased electric power set value). In this case, since the controller 140 can control the change in the generated power “PV” in real time by the charge / discharge power “BT”, the AC output power “AC” is not affected, but The electric power is affected by the power consumption change of the load 40.

  Therefore, the change in the power consumption of the load 40 is absorbed by taking in the measured value of the power consumption (total power consumption) of the load 40 obtained by the power sensor 60. Electricity sales and purchase power shall be set externally. For example, the power selling / purchasing power setting value may be set according to an operation on the user interface unit, or may be set by a user via a network.

Specifically, the controller 140
AC command value = Load power consumption measurement value-Electricity purchase power set value (3)
To set the AC command value.

For example, if you set power purchase power setting value = 0 that has the least effect on power system 2,
AC command value = Load power consumption measurement value (4)
It becomes. That is, the load power consumption measurement value may be directly replaced with the AC command value to perform control, and control can be performed without causing a time lag due to measurement / communication / calculation between devices.

  FIG. 3 is a flowchart of the power control method according to the present embodiment.

  As shown in FIG. 3, in step S <b> 11, the controller 140 acquires a measured value of the power consumption (total power consumption) of the load 40 obtained by the power sensor 60. The control signal line between the controller 140 and the power sensor 60 is not limited to a wired line, and may be configured wirelessly.

  In step S12, the controller 140 sets an AC command value according to the above equation (3) based on the measurement value acquired in step S11 and the externally set power selling / purchasing power setting value.

  In step S13, the controller 140 controls charging / discharging of the storage battery 20 based on the AC command value set in step S12 so that the AC output power “AC” becomes the AC command value. Specifically, the charge / discharge power “BT” obtained by BT = AC command value−PV is set in the storage battery 20.

  As described above, the controller 140 is based on the measurement value obtained by the power sensor 60 that measures the power consumption of the load 40 in the operation mode for controlling the power purchase power to a constant value. The AC command value is set so that the power becomes the constant value, and charging / discharging of the storage battery 20 is controlled so that the AC output power becomes the AC command value. Thereby, even if it is a case where the solar cell 10 whose electric power generation amount is difficult to control is used, it is possible to control the electric power selling / purchasing power to a constant value by controlling the charging / discharging of the storage battery 20, so It is possible to prevent adverse effects.

[Application Example of First Embodiment]
Next, an application example of the first embodiment will be described with reference to FIG. In the first embodiment described above, priority is given to controlling the power sale / purchasing power to a constant value, so charging / discharging of the storage battery 20 is controlled in the event. Of course, for the protection of the storage battery 20, protection control that does not discharge or charge any further when the remaining storage battery level (overdischarge, overcharge) has been reached is performed. It is more effective to perform automatic control that limits the charge / discharge amount or suppresses the PV power generation amount. If the above method is set as the automatic operation mode, detailed control from outside is not performed each time, and optimal control without affecting the system becomes possible.

As shown in FIG. 4, in this application example, the controller 140 is set when the AC command value is set, and the charge level of the storage battery 20 is set lower than an upper limit threshold value (for example, 95%) indicating overcharge. When the first threshold value (for example, 85%) is exceeded, charging / discharging of the storage battery 20 is controlled so that the AC output power becomes a value according to the AC command value, and charging to the storage battery 20 is limited. Specifically, the charging power is limited to half of the rated power of the DC / DC converter 120 when 85% is exceeded.
Further, the controller 140 controls to suppress the power generation of the solar cell 10 when the AC command value is set and the charge level of the storage battery 20 exceeds the first threshold value. The method for suppressing the generated power of the solar cell may be any control generally performed when the system voltage is increased or when overtemperature protection is performed. Specifically, the DC / DC converter 110 normally Stop the maximum power point tracking control (MPPT control) being performed, shift the operating point voltage of the solar cell, or measure the power of the DC / DC converter 110 output. The converter 110 input voltage may be increased.

  Thereby, possibility that the storage battery 20 will be in an overcharge state can be reduced, controlling the electric power sales purchasing power to the value according to a fixed value.

  Further, the controller 140 is a second threshold value (for example, 15%) that is set when the AC command value is set and the charge level of the storage battery 20 is set higher than a lower limit threshold value (for example, 5%) indicating overdischarge. The discharge of the storage battery 20 is limited while controlling the charge / discharge of the storage battery 20 so that the AC output power becomes a value according to the AC command value. Specifically, the amount of discharge is limited to half of the rated power, as in the case where the charging of the storage battery 20 is limited.

  Thereby, possibility that the storage battery 20 will be in an overdischarged state can be reduced, controlling the electric power sales purchasing power to the value according to a fixed value.

[Second Embodiment]
Hereinafter, the difference between the second embodiment and the first embodiment will be mainly described. FIG. 5 is an overall configuration diagram of the power control system according to the second embodiment.

  As shown in FIG. 5, the power control system according to the present embodiment is different from the first embodiment in that it further includes a power management apparatus 200 for performing power management. Such a power management apparatus 200 may be referred to as a HEMS (Home Energy Management System) or a BEMS (Building Energy Management System).

  In the present embodiment, the power management apparatus 200 acquires a measured value of the power consumption (total power consumption) of the load 40 obtained by the power sensor 60. Moreover, the power management apparatus 200 sets an AC command value by the above-described formula (3) based on the acquired measurement value (load power consumption measurement value) and the externally set power selling / purchasing power setting value. Specifically, the power management device 200 notifies the controller 140 of the hybrid power conditioner 100 of the AC command value obtained by the above equation (3), thereby causing the hybrid power conditioner 100 (the controller 140 to transmit the AC command value). ). And the controller 140 controls charging / discharging of the storage battery 20 similarly to 1st Embodiment based on the set AC command value. Thus, in this embodiment, the power management apparatus 200 corresponds to a command value setting unit, and the controller 140 corresponds to a charge / discharge control unit.

  According to the present embodiment, the processing load of the hybrid power conditioner 100 can be reduced by setting the AC command value not by the hybrid power conditioner 100 but by the power management apparatus 200. In the present embodiment, the control described in the application example of the first embodiment may be performed.

[Other Embodiments]
As described above, the present invention has been described according to each embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In each of the embodiments described above, the solar cell 10 that receives sunlight and generates power is used as the power generation device. However, for example, a wind power generation device that generates power by receiving wind power may be used instead of the solar cell 10.

  In each of the embodiments described above, the power sensor 60 is provided on the switchboard 50. However, the power sensor 60 may be provided on the outlet device, or the power sensor 60 may be provided on the load 40 itself.

  Further, in each of the above-described embodiments, the power sensor 60 measures the power consumption (total power consumption) of the load 40. However, as shown in FIG. 6, the power sensor 60 measures the power sale purchased power. It is good. From the above formula (2), the power consumption (total power consumption) of the load 40 can be obtained from the power sale power purchase power and the AC output power “AC”. AC command value can be set. Or it is good also as a structure which measures both the power consumption (total power consumption) of the load 40, and power purchase power purchased.

  In the second embodiment described above, the AC command value is set by the power management apparatus 200. However, as shown in FIG. 7, information extraction and information are performed between the power management apparatus 200 and the hybrid power conditioner 100. In the configuration in which the gateway device 300 for performing the conversion is provided, an AC command value may be set by the gateway device 300.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

  L1 to L5 ... Electric power line, 1 ... Consumer, 2 ... Electric power system, 10 ... Solar battery, 20 ... Storage battery, 40 ... Load, 50 ... Switchboard, 60 ... Power sensor, 100 ... Hybrid power conditioner, 110 ... DC / DC converter, 120 ... DC / DC converter, 130 ... DC / AC converter, 140 ... controller, 200 ... power management device, 300 ... gateway device

Claims (6)

A function of converting electric power obtained by power generation of the power generation device and discharging of the storage battery into alternating current and outputting it to the power system and the load, and converting alternating current power from the power system into direct current and outputting to the storage battery A power conversion device having a function,
A command value setting unit for setting a command value for device input / output power, which is AC power input / output by the own device;
A charge / discharge control unit for controlling charge / discharge of the storage battery,
The command value setting unit is configured to control power purchase power, which is AC power input / output to / from the power system, to a constant value, in a measured value of power consumption of the load and / or the power purchase. Based on the measured value of the electric power, the command value is set so that the electric power sold power purchase power becomes the constant value,
The charge / discharge control unit controls charging / discharging of the storage battery so that the device input / output power becomes the command value when the command value is set by the command value setting unit. Conversion device.   The charge / discharge control unit is when the command value is set by the command value setting unit, and the charge level of the storage battery exceeds a first threshold value set lower than an upper limit threshold value indicating overcharge. 2. The charging of the storage battery is limited while controlling charging / discharging of the storage battery so that the device input / output power becomes a value in accordance with the command value. Power conversion device.   A power generation suppressing unit that controls to suppress power generation of the power generation device when the command value is set by the command value setting unit and the charge level of the storage battery exceeds the first threshold value; The power converter according to claim 2, further comprising:   The charge / discharge control unit is when the command value is set by the command value setting unit, and the charge level of the storage battery falls below a second threshold set higher than a lower limit threshold indicating overdischarge. 4. The discharge of the storage battery is limited while controlling the charge / discharge of the storage battery so that the device input / output power becomes a value according to the command value. The power conversion device according to claim 1. A power generator,
A storage battery,
A function of converting electric power obtained by power generation of the power generation device and discharging of the storage battery into alternating current and outputting it to a power system and a load, and converting alternating current power from the power system into direct current to the storage battery A power control system having a function of outputting, a power control system comprising:
A power measuring unit that measures the power consumption of the load and / or the purchased power that is AC power input and output to and from the power system;
A command value setting unit for setting a command value for device input / output power that is AC power input / output by the power converter;
A charge / discharge control unit for controlling charge / discharge of the storage battery,
The command value setting unit is configured so that, in an operation mode for controlling the power sale power purchase power to a constant value, the power sale power purchase power becomes the constant value based on a measurement value obtained by the power measurement unit. Set the command value to
The charge / discharge control unit controls charging / discharging of the storage battery so that the device input / output power becomes the command value when the command value is set by the command value setting unit. Control system. A function of converting electric power obtained by power generation of the power generation device and discharging of the storage battery into alternating current and outputting it to the power system and the load, and converting alternating current power from the power system into direct current and outputting to the storage battery A power control method for a power conversion device having a function,
In the system operation mode for controlling the power selling / purchasing power, which is AC power input / output to / from the power system, to a constant value, based on the measured power consumption of the load and / or the measured power selling power purchased, A step of setting a command value for device input / output power, which is AC power input / output by the power conversion device, so that the power sale power purchase power becomes the constant value;
And B for controlling charging / discharging of the storage battery so that the device input / output power becomes the command value set in the step A.

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