KR102019087B1 - Control method of photovoltaic energy storage system - Google Patents

Abstract

Disclosed are a photovoltaic power generation energy storage system which is operated by being divided into a daytime operation mode and a night operation mode, and a control method of a photovoltaic power generation energy storage system which includes a method of operating the photovoltaic power generation energy storage system, and in particular, a battery replacement method for supplying power to a DC load without a breakdown of a DC power supply, determining whether a battery is abnormal, and replacing the battery.

Description

CONTROL METHOD OF PHOTOVOLTAIC ENERGY STORAGE SYSTEM}

The present invention relates to a control method of a photovoltaic energy storage system, and more particularly, to a photovoltaic energy storage system operating by being divided into a daytime operation mode and a nighttime operation mode, and operating the photovoltaic energy storage system. The present invention relates to a method of controlling a photovoltaic energy storage system including a method of replacing a battery, in particular, a battery that can be replaced without disconnecting a DC power source.

The photovoltaic power generation system refers to a power generation system that generates power and electric energy by using at least one solar cell using a semiconductor device capable of converting solar energy into electrical energy. Such a photovoltaic power generation system uses one or two or more solar cells as necessary, and connects them in series or in parallel. This general type of solar power system is disclosed in the air in various forms.

As a characteristic part of the above photovoltaic power generation system, since solar light, which is the source of electric energy, is supplied only during the daytime, power generation is not possible at night, and power generation output may fluctuate depending on weather conditions during the daytime will be. Accordingly, a general photovoltaic power generation system organizes a separate energy storage system.

In addition, as described above, a portion of the electrical energy produced during a large amount of sunshine is allocated as surplus power and stored in the energy storage system to operate together with photovoltaic power generation.

The energy storage system as described above is increasing in weight in the solar power system due to factors such as capacity increase, price drop, and long life, and it also increases in importance as it contributes to stable power supply. to be.

The energy storage device as described above can be configured in various forms according to the energy source, such as a battery for storing electrical energy, a heat storage tank for storing thermal energy, a hydrogen generator for storing chemical energy, various forms for this Is disclosed.

For example, Korean Patent No. 10-1469904 discloses an integrated power control panel mode control system of a photovoltaic power generation facility having an energy storage device. The registered patent discloses a series of technologies for minimizing the electricity bill through optimal control of grid-connected solar power generation facilities based on the power demand pattern of the target building, real-time monitoring data of solar power generation according to the amount of sunshine, and real-time grid power price. Doing.

In addition, Korean Patent Laid-Open No. 1-2016-0028884 discloses a method of operating a power supply system equipped with a photovoltaic device and a power storage device, and Korean Patent Laid-Open Publication No. 10-2017-0038640 refers to an energy storage device power interlocking control system and control. A method is disclosed.

In addition, Korean Patent No. 10-1651772 discloses a plurality of energy storage power control systems that can improve system efficiency, and Korean Patent No. 10-1766433 links solar power generation and power charging / discharging power systems. Disclosed is an energy storage system including a power conversion device for operation, and an energy storage system for automatically switching to a buck mode or a boost mode with reference to an average of current values flowing to an operating region (CCM / DCM) and an inverter. .

All of the above-mentioned Korean published patents and registered patents are judged to be completely different technologies from those of the present invention.

The present invention solves the problems of the prior art as described above, and as a configuration and method different from the currently disclosed technology, and discloses a photovoltaic energy storage system and a control method of a photovoltaic energy storage system using the same. There is a purpose.

The present invention to achieve the object of the present invention as described above,

A solar cell unit including one or more solar cells as a photovoltaic energy storage system using one or more batteries; A solar cell unit controlling power generated by the solar cell unit and including a DC / DC converter; A solar cell breaker installed between the solar cell unit and the solar cell unit; A DC link unit installed between the solar cell unit and the power system; A power converter installed between the DC link unit and the power system and including a DC / AC bidirectional power converter; A battery unit capable of storing electrical energy, including one or more batteries; A battery unit which controls the charging of the battery unit, is connected to the solar cell unit and the power conversion unit using the DC link unit as a contact point, and includes a DC / DC converter; A battery breaker and a battery switch installed between the battery unit and the battery unit; A DC load unit installed between the battery unit and the DC load, the DC load unit including a DC / DC converter to supply DC power to the DC load; And it provides a photovoltaic energy storage system including a control unit for controlling the operation of the solar cell unit, the battery unit, the DC link unit, the power conversion unit and the DC load unit.

And as a control method of the photovoltaic energy storage system for supplying power to the DC load and charging the battery using the photovoltaic energy storage system,

System status check step (S1) to check the overall system status of the photovoltaic energy storage system; And when the whole system is normal in the step (S1), if the control unit determines that the current time (t) exceeds the daytime boundary time (td) and falls within the range of less than the night boundary time (tn) the current time (t) If it is determined that it belongs to the daytime, and the range is out of the above range, the day and night judgment step (S2) to determine that the current time (t) belongs to the night,

If it is determined in step S2 that the current time t belongs to daytime, the controller operates the solar energy storage system of the present invention in a daytime operation mode step S31; After the step S31, the controller performs a charging state checking step S32 of checking the charging state of the battery unit.

In the step S32, when the state of charge of the battery in the battery unit is a low voltage or an overvoltage state, the battery remaining scenario mode S5 is executed, and in the step S32, the state of charge of the battery in the battery unit is a normal voltage. By performing the operation mode determination step (S33) of measuring the voltage (PV) of the electrical energy produced by the solar cell unit to determine the operation of the solar cell unit,

In the step S33, if the initial operating voltage PVr exceeds 150 V, which is an operation start voltage, or the current voltage PV is within a range of more than 100 V and less than 500 V, which is an operation holding voltage range, the system state checking step S1 is performed. In operation S33, when the initial operation voltage PVr is 150 V or less or the current voltage PV is out of the operation maintenance voltage range, an operation standby mode S34 for stopping power generation of the solar cell unit is performed. After the step S34, the day and night determination step S2 is performed.

If the current time (t) is determined to belong to the night in the step (S2), the night operation mode step (S41) for the control unit to operate the photovoltaic energy storage system of the present invention at night operation; And after the step (S41) and the control unit performs a charge state check step (S42) for checking the state of charge of the battery unit,

In the step S42, when the state of charge of the battery in the battery unit is a low voltage or an overvoltage state, the battery remaining scenario mode S5 is executed, and in the step S42, the state of charge of the battery in the battery unit is a normal voltage. It provides a control method of a photovoltaic energy storage system for performing the system status check step (S1).

In the step S31, the DC / DC converter in the solar cell unit is operated in the maximum power point following mode, the DC / AC power converter in the power converter is preferably operated in the inverter mode.

In the above step S41, the DC / AC power converter in the power converter is operated in the converter mode, the system current reference value of the DC link unit is preferably a negative (-) value.

In the above, in the step S31 and the step S41, supplying the DC power to the DC load is preferably such that the battery unit.

In the above step, in order to check the state of charge of the battery when the state of charge check step (S32, S42) is started, a state of charge check step (S321) of determining whether the state of charge (soc) of the battery can be confirmed; If it is possible to check the state of charge (soc) in the step (S321), the soc check step of comparing the state of charge (soc) with the minimum allowable sic value (soc_mi), the maximum allowable sic value (soc_mx) previously input ( S322); In the step S322, when the state of charge value soc is less than the minimum allowable soc value soc_mi or less than the maximum allowable soc value soc_mx, it is determined that the state of charge of the battery is normal and the normal voltage determination step S324 is performed. To terminate the charging state checking step (S32, S42),

In the step S322, when the state of charge value soc is less than the minimum allowable soc value soc_mi or exceeds the maximum allowable soc value soc_mx, the battery remaining amount scenario step S5 is executed. If the charge state value (soc) is impossible to check in S321, the battery voltage checking step (S323) comparing the voltage value BV of the battery with the minimum allowable voltage value BV_mi and the maximum allowable voltage value BV_mx previously inputted. ); In operation S323, when the battery voltage value BV is greater than the minimum allowable voltage value BV_mi and less than the maximum allowable voltage value BV_mx, it is determined that the state of charge of the battery is normal and the normal voltage determination step S324 is performed. To terminate the charging state checking step (S32, S42),

In the step S323, when the battery voltage value BV is less than or equal to the minimum allowable voltage value BV_mi or greater than or equal to the maximum allowable voltage value BV_mx, the battery remaining amount scenario step S5 is performed.

In the step, the battery voltage determination step (S51) for determining whether the battery in the battery unit is a low voltage or an overvoltage when the battery remaining scenario mode (S5) is started; In the step S51, if it is determined that the batteries in the battery unit is a low voltage state, the low voltage warning step (S52) of the control unit to inform the user that the battery is in a low voltage state; A battery low voltage state checking step (S53) of checking a low voltage state of the battery after the step (S52); In operation S53, when the current battery voltage value BV is lower than the previously input limit allowable voltage value BV_lim and the charging count cn is higher than the maximum charge count value cmx previously input, the battery low voltage error. After the notification step (S55) is carried out the system status check step (S1),

When the current battery voltage value BV is equal to or higher than the limit allowable voltage value BV_lim previously input in the step S53 or the charge count cn is equal to or smaller than the maximum charge count cmx previously input. To perform the charging step (S54) for charging the multi-sided battery,

In the step S51, if it is determined that the batteries in the battery unit are in an overvoltage state, the control unit notifies the user that the battery is in an overvoltage state (S56); After the step (S56), after performing the battery charge stop step (S57) for blocking the charge to the battery unit 210 and performs the battery voltage determination step (S51).

In the above, when the charging step (S54) is carried out while charging the battery unit, and comparing the charging time (ct) measured while starting the charging is more than 2 hours, the charging time (ct) is It is preferable to charge the battery until more than two hours.

In addition, after charging the battery unit according to the charging step (S54), the battery charge state value (soc) exceeds the previously input charge allowable soc value (soc_ps) or the battery voltage value (BV) If the rated voltage value (RV) is exceeded, the system state checking step (S1) is performed,

After charging the battery unit according to the step (S54), the battery charge state value (soc) is less than the input charge allowable soc value (soc_ps) and the battery voltage value (BV) is the rated voltage value ( RV) or less, it is preferable to perform the step (S53) by adding one to the current charge count (cn).

And a method for replacing the battery in the battery unit in the solar energy storage system of the present invention, the battery replacement setting step of the control unit is set to the battery replacement mode (S61); In the step (S61), when the solar energy storage system of the present invention is operated in the daytime operation mode night operation mode change step (S62) for changing to the night operation mode; A battery replacement step (S63) of replacing the battery by blocking the magnetic contactor in the battery unit when the step (S62) or the step S61 is determined to be a night operation mode; After the step S63 ends, the controller releases the battery replacement mode and operates in the day or night operation mode.

In the above, before the magnetic contactor in the battery unit is blocked in step S62, it is preferable to change the DC / DC converter in the battery unit to a constant voltage charging mode and maintain the constant voltage.

The photovoltaic energy storage system and control method thereof according to the present invention can be used to constantly and effectively charge a battery regardless of daytime, nighttime, and insolation, and provide a uniform DC voltage to a DC load, and also cause a failure of the battery. You can quickly determine whether it is safe and take action safely.

1 to 3 is a structural diagram of the photovoltaic energy storage system of the present invention.
Figure 4 is a flow chart of day and night photovoltaic power storage system control using the photovoltaic energy storage system of the present invention.
5 is a detailed flowchart of the state of charge check step of the present invention.
6 is a detailed flowchart of the battery remaining scenario mode of the present invention.
Figure 7 is a flow chart of battery replacement in the photovoltaic energy storage system of the present invention.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. The following description is to aid the understanding and practice of the present invention, but not to limit the present invention thereto. Those skilled in the art will appreciate that various modifications and changes can be made within the spirit of the invention as set forth in the claims below.

1 to 3 is a structural diagram of the photovoltaic energy storage system of the present invention. Hereinafter, the components and operation of the photovoltaic energy storage system of the present invention will be described with reference to FIGS. 1 to 3.

Prior to the description, parts shown in solid lines in FIGS. 1 to 3 represent physical circuit connection relationships in which electrical energy is transmitted and received, and parts shown in dotted lines in FIG. 1 may exchange signals or information between components. The connection relationship is communicatively connected so that a solid line and a dotted line connection relationship are independently formed without a contact point in FIG. 1.

And the dotted arrow direction in Figures 2 to 3 indicates the flow direction of the electrical energy.

As shown in FIG. 1, the photovoltaic power generation energy storage system of the present invention is applied to a power generation system that generates power and electric energy using a solar cell (C). The solar cell C may be configured as one, or two or more may be configured to be connected in series and in parallel. In the present invention, at least one solar cell (C) for producing electrical energy as described above is used to configure the solar cell unit 110.

And in order to control the power produced by the solar cell unit 110, the solar cell unit 100 is connected to the solar cell unit 110. The solar cell unit 100 may include a series of sensors and computing devices for controlling the operation of the solar cell unit 110, a storage device, and one or more programs built into the storage device. Since the configuration of the branch 100 is a general thing, a description thereof will be omitted.

In particular, the solar cell unit 100 includes a DC / DC converter for converting the DC power supply voltage of the electrical energy produced by the solar cell unit 110, the DC / DC converter of the solar cell unit 100 As one direction, the DC power supply voltage of the electrical energy produced by the solar cell unit 110 is converted to move only in the direction of the arrow shown on the solar cell unit 100 of FIG.

In addition, a solar cell breaker 120 is installed between the solar cell unit 100 and the solar cell unit 110.

In addition to the electric energy produced by the solar cell unit 100 and the solar cell unit 110, other electric energy can be introduced into the power grid, that is, the power system G, between the DC link unit 300 and the power converter. 310 is connected.

The DC link unit 300 is a portion for determining the reference value of the amount of current to be transmitted to the power system (G) with respect to the electrical energy transmitted from the solar cell unit 100.

In addition, the power conversion unit 310 connected to the DC link unit 300 converts the AC power drawn in the power system (G) into a DC power, or the DC power transmitted from the DC link unit 300 Including a DC / AC bidirectional power converter for converting into AC power, when converting DC power into AC power (inverse conversion) and transmitting to the power system G, it operates as an inverter, and on the contrary, transmits power from the power system G. When converting AC power into DC power (forward conversion), it is operated as a converter.

And the photovoltaic energy storage system of the present invention, in order to store a portion of the electrical energy produced by the solar cell unit 110, includes a battery unit 210 including one or more batteries. At least one battery included as a component of the battery unit 210 may be used as long as the battery can charge electrical energy.

In addition, in order to control the charging of the battery unit 210, the battery unit 200 is connected to the battery unit 210. The battery unit 200 is also connected to the solar cell unit 100 and the power conversion unit 310 by using the DC link unit 300 as a contact point.

The battery unit 200, in the daytime operation mode, serves to charge the battery unit 210 by transferring electrical energy transmitted from the solar cell unit 100 to the battery unit 210 and at night. In operation mode or when the battery is in a low voltage state, electric energy transmitted from the power system G is transferred to the battery unit 210 to charge the battery unit 210.

In addition, the battery unit 210 may discharge electric energy in the battery unit 210 and supply it to other components if necessary.

To this end, the battery unit 200 may include a series of sensors and a computing device for controlling the operation of the battery unit 210, a storage device and one or more programs built into the storage device, such a battery Since the configuration of the unit 200 is general, description thereof will be omitted.

In particular, the battery unit 200 includes a DC / DC converter for converting the DC power supply voltage of the electrical energy, the DC / DC converter of the battery unit 200 is a bi-directional, to measure the DC power supply voltage of the electrical energy Only in the direction of the arrow indicated on the battery unit 200 of 1 to move.

In addition, a battery breaker 220 and a battery switch 230 are included and connected between the battery unit 200 and the battery unit 210.

In addition, in order for the DC power produced by the solar cell unit 110 to supply DC power directly to the DC load D required without conversion to AC power, the DC load unit 400 is connected to the battery unit 200 and the It is connected between the DC load (D).

The DC load unit 400 is a one-way DC / DC converter for converting a DC power voltage in order to provide a DC power supplied from the battery unit 200 or the battery unit 210 to the DC load D. It includes.

In addition, the present invention includes a control unit 500 for controlling the operation of the solar cell unit 100, the battery unit 200, the DC link unit 300, the power conversion unit 310 and the DC load unit 400. do. The control unit 500 may include one or more arithmetic and storage devices, and one or more programs installed in the storage device to control the above components.

In addition to the above components, the controller 500 may directly control operations of the solar cell unit 110, the battery unit 210, the breakers 120 and 220, and the switch 230. Alternatively, the operation of the solar cell unit 110 and the solar cell breaker 120 is controlled by the solar cell unit 100, and the operation of the battery unit 210, the battery breaker 220, and the battery switch 230 is performed. The battery unit 200 may be controlled.

As described above, during the day in which the solar cell unit 110 produces power, electric energy flows as shown by the dotted arrow in FIG. 2. As shown in FIG. 2, electrical energy produced by the solar cell unit 110 may be converted into an AC power source through the solar cell unit 100 and the power converter 310, and may be transmitted to an electric power system G. Alternatively, the battery in the battery unit 210 may be charged via the battery unit 200, or DC power may be supplied to the DC load D via the DC load unit 400.

In addition, when the solar cell unit 110 does not supply electrical energy at night or due to weather conditions or other problems, as shown by the dotted line arrow in FIG. 3, the AC power is supplied from the power system G. After conversion to a power source, the battery unit 210 or the DC load (D) may be provided.

The flow direction of the electrical energy shown in FIGS. 2 and 3 is a general case, and in some cases, the battery in the battery unit 210 needs to be replaced or repaired in a state in which electrical energy cannot be supplied due to failure or damage. Cases may occur. The operation procedure for this particular situation will be described later.

4 is a structural view of the operation of the photovoltaic energy storage system of the present invention. Hereinafter, the operation of the photovoltaic energy storage system of the present invention will be described with reference to FIGS. 1 and 4.

When the photovoltaic power generation system including the photovoltaic energy storage system of the present invention starts to operate, first, the control unit 500 checks the overall system state of the photovoltaic energy storage system (S1). Is carried out. In the step (S1), if the normal operation is not possible due to the failure or damage of any one of the components, or if the risk of a safety accident may occur during operation, the control unit 500 immediately exits the emergency termination step (S11) To shut down and exit all systems.

And if it is determined in the step (S1) that the entire system can operate normally without failure, the control unit 500 determines the day and night determination step of determining whether to set the solar energy storage system in daytime operation mode or night operation mode ( S2) is performed.

The criterion for determining the day or night in the step (S2) is based on the current time (t), the current time (t) is located above the daytime boundary time (td) and less than the night boundary time (tn) If it is present, it is determined as day, and if the current time t is out of the range, it is determined as night. For example, if the daytime boundary time td is 6 am (td = 6) and the nighttime boundary time tn is set to 6 pm (tn = 18), then the current time t is When it is in the range of more than 6 and less than 18, it is judged as daytime, and when it is out of this range, it is judged as night.

If the current time (t) is determined to be daytime in the step (S2), it is assumed that the solar cell unit 110 can generate power, the control unit 500 is a photovoltaic energy storage system of the present invention The weekly operation mode step (S31) of operating in the daytime operation mode is performed.

In step S31, the solar cell unit 100 follows the maximum power point of the DC / DC converter in the solar cell unit 100 to comply with the amount of electric energy generated by the solar cell unit 110. Operates in (Maximum Power Point Tracking, MPPT) mode. Accordingly, the DC link unit 300 determines the reference value of the amount of current to be transmitted to the power system G by the portion when the predetermined voltage or more, while maintaining at a predetermined constant voltage.

Here, in order to transmit power to the power system (G), the DC / AC power converter in the power converter 310 operates in an inverter mode.

The predetermined voltage may be, for example, 350Vdc for the single-phase AC220V and 620Vdc for the three-phase AC380V.

After the step S31, the controller 500 performs a charge state checking step S32 of checking the state of charge of the battery unit 210 through the battery unit 200.

In the step S32, the next step is determined according to the state of charge of the battery in the battery unit 210. When the state of charge of the battery is a low voltage or an overvoltage state, the battery remaining scenario mode S5 is performed. When the state of charge of the battery is a normal voltage, an operation mode determination step (S33) of determining an operation of the solar cell unit 110 is performed.

The detailed configuration and steps of the checking of the state of charge (S32) and the remaining battery power scenario mode (S5) that can be performed after the step (S32) will be described later through separate drawings.

In operation S32, when the state of charge of the battery is a normal voltage, an operation mode determination step S33 of determining an operation of the solar cell unit 110 is performed. In the step (S33) to determine the next operation mode by measuring the voltage (PV) of the electrical energy produced by the solar cell unit 110 is produced.

At this time, as a factor for determining the next step in the step (S33) as the initial operating voltage (PVr) when the solar cell unit 110 starts to generate power or the current voltage (PV) of electrical energy produced by the current power generation use.

In the step (S33), if the initial operating voltage PVr exceeds the operating start voltage 150V, or if the current voltage PV is in the range of more than 100V and less than 500V operating operating voltage range, the solar cell unit 110 Since it means that the development of) is normally performed, the system of the present invention returns to the step (S1) of checking the state of the system again to maintain the operation of the present invention unless a separate operation termination command is given.

In operation S33, when the initial operating voltage PVr is measured to be 150 V or less, or if the current voltage PV is measured to be 100 V or less or 500 V or more out of the range, the solar cell unit 110 may generate electricity. The operation standby mode (S34) for stopping the operation is performed.

When the step (S34) is performed, the power generation of the solar cell unit 110 is stopped. Nevertheless, since the DC load D must be provided with a 48 V DC power continuously, in this case, the power system G However, it is preferable to receive power from the charged battery unit 210.

After performing the step (S34), the day and night determination step (S2) to determine the day and night again to perform the day or night operation mode determination.

Day operation is performed by repetition of the above steps.

And if the current time (t) is determined to be nighttime in the day and night determination step (S2), the control unit 500 operates the night operation mode step (S41) for operating the solar energy storage system of the present invention in the night operation mode. Conduct.

If the step immediately before the step (S41) is carried out in the daytime operation mode and the DC link unit 300 maintains the constant voltage, while switching to the night operation mode through the step (S41) The battery unit 200 slowly increases the battery charging current value, and the DC link unit 300 changes the system current reference value to a negative (−) value, and the DC / AC power converter of the power converter 310. By operating in the converter mode to receive power from the power system (G).

In addition, in the daytime operation mode or the night operation mode, the DC load unit 400 may stably supply power to the DC load unit 400 and the DC load D to the DC unit 400.

When the initial operation mode performs the step (S41) in the night operation mode, first, the battery unit 200, the DC / DC converter of the DC link unit (2) through the battery unit 210 through the battery discharge; Provide and maintain a constant voltage at 300), for example 350Vdc for single-phase 220Vac and 620Vdc for three-phase 380V.

As described above, while switching to the night operation mode (S41), the battery unit 200 slowly increases the battery charging current value in order to receive power for charging the battery through the power system G, and the DC link The unit 300 changes a system current reference value to a negative value and operates the DC / AC power converter of the power converter 310 in a converter mode to receive power from the power system G.

Provided to the DC load unit 400, to stably provide a 48V DC power to the DC load (D), after that the DC / AC power converter of the power converter 310 operates in the converter mode to the Supplying power from the power system (G) may include a separate step to maintain the voltage of the power supplied to the DC load (D).

When the power is supplied from the power system G as described above, the battery unit 200 changes the current direction of its DC / DC converter to charge the battery of the battery unit 210 in the constant current or constant voltage mode.

After performing the step (S41), the charge state check step (S42) to check the battery charge state of the battery unit 210 is carried out. In the step S42, as in the step S32, when the battery unit 210 is in a low voltage or an overvoltage state, the battery remaining scenario mode S5 is performed. When the battery unit 210 is determined to be the normal voltage in the step S42, the system returns to the step S1 of checking the state of the system again unless a separate operation termination command is given. To maintain the operation of the invention.

The night operation is performed by repetition of the above steps.

5 is a detailed flowchart of the charging state checking step (S32, S42). Hereinafter, a detailed operation procedure of the charging state checking step (S32, S42) will be described with reference to FIG.

As described above, the step of checking the state of charge (S32, S42) checks the state of charge of the battery unit 210 to perform the battery remaining scenario mode (S5) or the next step according to the day or night operation It is a step to decide whether to do it. To this end, the charging state checking step (S32, S42) first performs a charging state checking step (S321) to check the charging state of the battery unit 210.

At this time, the charging state checking step (S321) includes a step of checking whether the state of charge (soc) of the battery can be confirmed. The state of charge (soc) of the battery may be expressed as a percentage indicating a degree of charge of the battery unit 210. If the state of charge (soc) of the battery is 100% means that the battery unit 210 is fully charged, if 0% means that it is not charged at all.

Here, an additional battery management system (BMS) is additionally installed in the battery unit 210 or the battery unit 200 so as to easily check the state of charge (soc) of the battery. If there is, in step S321, the soc check step S322 is performed to determine whether the battery unit 210 is any one of a low voltage, a normal voltage, and an overvoltage by checking a state of charge (soc) of the battery. .

In the step S322, in order to determine whether the state of charge (soc) of the battery is within the normal voltage range, the minimum allowable soc value (soc_mi) and the maximum allowable value are previously provided to the controller 500 or the battery unit 200. The soc value (soc_mx) is input. The minimum allowable soc value (soc_mi) is generally input at 10%, and the maximum allowable soc value (soc_mx) is generally input. Such minimum and maximum allowable soc values (soc_mi, soc_mx) are input in the battery unit 210. This can be set considering the life of the batteries.

In the step S322, when the state of charge (soc) of the battery falls within the range of the minimum allowable soc value (soc_mi) or more than the maximum allowable soc value (soc_mx), the charge state (soc) value of the battery is Since it is within the normal voltage range, the normal voltage determination step (S324) is performed to confirm that the battery in the battery unit 210 is operating at the normal voltage, and then the operation according to the above-described day or night with FIG. 4 is performed. Do it.

In step S322, when the state of charge (soc) of the battery is less than the minimum allowable soc value (soc_mi), the low voltage, and the state of charge (soc) of the battery exceeds the maximum allowable soc value (soc_mx). In this case, since it may be determined as an overvoltage, the battery remaining scenario mode S5 is performed.

In addition, in the step (S321), when the battery management system is not separately added to the battery unit 210 or the battery unit 200 is not installed and can not determine the state of charge (soc), the battery unit 210 In step S323, a battery voltage checking step of determining based on the battery voltage value BV is performed.

At this time, the battery voltage value (BV) is expressed as a percentage, it is preferable to make the rated voltage range of 100%.

In step S323, in order to determine whether the battery voltage value BV is within a normal voltage range, the controller 500 or the battery part 200 may have a minimum allowable voltage value BV_mi and a maximum allowable voltage value in advance. (BV_mx) is input. In general, when the battery voltage value BV is regarded as 100% based on the rated voltage 12V, the minimum allowable voltage value BV_mi is 85% and the maximum allowable voltage value BV_mx is generally input at 120%. The minimum and maximum allowable voltage values BV_mi and BV_mx may be adjusted in consideration of values such as the lifespan or rated voltage of the batteries in the battery unit 210.

In the step S323, when the battery voltage value BV falls within a range of more than the minimum allowable voltage value BV_mi and less than the maximum allowable voltage value BV_mx, the battery voltage value BV falls within a normal voltage range. Since belonging to, the normal voltage determination step (S324) is carried out to confirm that the battery in the battery unit 210 is currently operating at the normal voltage, and then to perform the operation according to the above-described day or night with FIG.

In operation S322, when the battery voltage value BV is less than or equal to the minimum allowable voltage value BV_mi, a low voltage is determined, and when the battery voltage value BV is greater than or equal to the maximum allowable voltage value BV_mx, it is determined as an overvoltage. In this case, the battery remaining scenario mode S5 is performed.

The charging state checking step (S32, S42) is carried out through the above procedure.

6 is a detailed flowchart of the battery remaining scenario mode (S5). Hereinafter, a detailed procedure of the battery remaining scenario mode S5 will be described with reference to FIG. 6.

As described above, the battery remaining scenario mode S5 is a separate procedure performed when the battery in the battery unit 210 is determined to be low voltage or overvoltage in the charging state checking steps S32 and S42.

When the battery remaining scenario mode S5 is started, it is first determined whether the battery in the battery unit 210 is undervoltage or overvoltage. Therefore, the battery voltage determination step S51 is performed.

In this step, as the factor for determining the low voltage or overvoltage of the battery, the above-described battery charge state value (soc) and the minimum and maximum allowable soc values (soc_mi, soc_mx) related thereto or the battery voltage value (BV) Use the minimum and maximum allowable battery voltage values BV_mi and BV_mx.

If the battery charge state value (soc) is less than the minimum allowable soc value (soc_mi) or the battery voltage (BV) value is less than the minimum allowable battery voltage value (BV_mi) in the step (S51), the battery Since the batteries in the unit 210 are in a low voltage state, the controller 500 performs a low voltage warning step (S52) informing the user through a means such as a display.

Since the step S52 has been performed, since the remaining charge of the battery remains little, the control unit 500 draws power from the power system G and supplies a stable constant voltage of DC48V to the DC load unit 400. It is desirable to provide.

In this case, it is preferable that the control unit 500 draws power from the power system G. As described above, a situation in which the battery is not properly charged in the battery unit 210 is generally due to bad weather in a daytime situation. This is because the solar cell unit 110 occurs when a problem occurs in producing electrical energy. Therefore, in step S52, it is preferable to include a separate procedure for receiving power from the power system G and supplying power to the DC load unit 400.

In addition, in step S52, the charging count cn, which is a counter that increases by one, is initialized to the default value% d. The default value (% d) can be changed and set by the administrator as necessary, but it is preferable to simply set it to 0 or 1.

After the step S52 is performed, a battery low voltage state checking step S53 for checking a low voltage state of the battery is performed.

In the step S53, whether the batteries in the battery unit 210 are broken by using the limit allowable voltage value BV_lim and the maximum charging count cmx previously inputted to the controller 500 or the battery unit 200. To judge.

In more detail, the limit allowable voltage value BV_lim is set to determine whether the batteries have failed, and is set to a value lower than the minimum allowable voltage value BV_mi. For example, when the minimum allowable voltage value BV_mi dl is set to 85%, the limit allowable voltage value BV_lim may be set to about 80%.

The maximum charging count (cmx) is a counter that increases by one each time the next step is performed, and is set larger than the default value (% d) of the charging count (cn).

In the step S53, the battery voltage value BV currently measured is lower than the limit allowable voltage value BV_lim, and the charging count cn rising when the battery is charged in the next step is the maximum charge count (cmx). Higher than), it is determined that a functional problem occurs such as failure or damage of the battery, or the end of life, and after performing the battery low voltage error notification step (S55), the process returns to the above-mentioned day and night operation step. Returning to the day and night operation step as described above, in the system state check step (S1) to detect the error of the battery to perform the emergency shutdown step (S11) to stop all the systems.

However, when the step S53 is first entered, the charging count cn may be absent or set to 0, 1, or the like, and thus lower than the maximum charging count cmx. Therefore, the battery does not enter the step S55. A charging step (S54) of performing charging is performed.

In this case, the amount of power to charge the batteries in the battery unit 210 is added to the reference charging current value to the current of the DC load (D) to allow the battery to be charged in consideration of the power used by the DC load (D) The battery can be charged.

In addition, to supply power to the batteries in the battery unit 210, it is preferable to supply power through the power system (G), which is generally described as the battery (S52) is a low voltage This is because the power generation of the solar cell unit 110 is a problem caused by not being made stably due to weather or the like.

In the step S54, the battery is charged using the charging time (ct), the rated voltage value (RV), and the charge allowable soc value (soc_ps) while charging all the batteries in the battery unit 210. Determine if this has been done enough.

In this case, the rated voltage value RV is a rated voltage value of the batteries in the battery unit 210 that is input to the control unit 500 or the battery unit 200 in advance. For example, when the battery is composed of one 12V battery. In this case, the rated voltage value RV will be 12V, and when the eight 12V batteries are connected in series, the rated voltage value RV will be 96V.

In addition, the charge allowable soc value (soc_ps) is also a value input to the controller 500 or the battery unit 200 in advance, and is generally larger than the minimum allowable soc value (soc_mi) and smaller than the maximum allowable soc value (soc_mx). Is set to. For example, the applicant of the present invention, through repeated experiments, found that the charge allowable soc value (soc_ps) should be set to about 60%.

In the state set as described above, it is preferable to charge the battery at least 2 hours in the step S54. Therefore, it is determined whether the charging time (ct) to be measured from the start of charging is 2 hours or more. The charging is repeated until it is exceeded, and when the charging time ct exceeds 2 hours, the degree of current charge is measured using the battery state of charge value soc or the battery voltage value BV.

In the state where charging is performed for at least 2 hours as described above, the battery state of charge value soc exceeds the charge allowable soc value soc_ps previously input or the battery voltage value BV equals the rated voltage value. If RV) is exceeded, it means that all of the batteries in the battery unit 210 have been sufficiently charged, and thus, the main unit may return to the above-described main and night operation modes.

In the state where the battery has been charged for at least 2 hours as described above, the battery charge state value soc is less than the previously input charge allowable soc value soc_ps and the battery voltage value BV is equal to the rated voltage value. RV) or less, it means that the charging of the batteries has not yet been completed sufficiently, so that the battery low voltage state checking step S53 is added again by adding one to the charging count cn.

When the battery unit 210 is repeatedly charged, the battery unit 210 is repeatedly charged in the same order as described above. Even though the charging step S54 is repeatedly performed a predetermined number of times, the battery is not sufficiently charged. As described above, since a problem has occurred in the battery, it may be detected in step S53 and notified of an error (S55).

In the same manner as above, the corresponding procedure when the battery is in the low voltage state is performed.

In the battery voltage determining step S51, when the battery state of charge value soc exceeds the maximum allowable soc value soc_mx or the battery voltage value BV is greater than or equal to the maximum allowable voltage value BV_mx. The batteries in the battery unit 210 are determined to be in an overcharged state, and the controller 500 performs a battery overvoltage alarm (S56) informing the administrator through a display that the battery is overvoltage, and the battery unit 200. ) Performs a battery charge stop step (S57) of blocking the charging of the batteries in the battery unit 210.

When the battery charging stop (S57) is performed as described above, the charging of the battery unit 210 is stopped, but the batteries in the battery unit 210 should be continuously supplied with a constant voltage to the DC load unit 400. Thus, the charge of the battery can be naturally and continuously reduced. After the step S57, the battery voltage determination step S51 is repeated to check whether the battery voltage is in a normal state, and when it is determined that the battery voltage is in the normal state, the operation returns to the above-described main and night operation modes.

7 is a flowchart illustrating a procedure when a battery in the battery unit 210 is to be replaced in the solar energy storage system of the present invention. Hereinafter, the battery replacement procedure will be described with reference to FIG. 7.

As described with reference to FIG. 6, the photovoltaic energy storage system of the present invention may detect a situation in which the battery in the battery unit 210 does not operate normally due to end of life or failure or damage. When the above problem occurs, the manager must replace the battery in the battery unit 210, and even in the battery replacement situation, by providing a constant voltage to the DC load unit 400 continuously to the DC load (D) Power supply must not be interrupted.

To this end, when the administrator selects the battery replacement mode through the control unit 500, the control unit 500 performs a battery replacement setting step (S61).

In step S61, it is determined whether the present solar energy storage system of the present invention operates in the daytime operation mode or the night operation mode. In the step S61, the present invention operates in the daytime operation mode. If so, the night operation mode changing step (S62) of changing the current operation to the night operation mode regardless of time is performed.

The reason for doing so is that when the present invention is carried out in the daytime operation mode and receives the electrical energy produced by the solar cell unit 110, the solar energy unit 110 according to the amount of insolation according to the amount of solar energy produced by the solar cell unit 110. When the DC load unit 400 cannot supply sufficient constant voltage, the battery unit 210 cannot supply extra electricity. This can cause disruptions in supplying electricity to the car.

Therefore, it is preferable to supply electricity to the DC load unit 400 by receiving power stably from the system power source G, and changing to a night operation mode, as described above.

If the step S62 or the current operation in the night operation mode, the battery replacement step (S63) is carried out.

In the step S63, when the DC / DC converter in the battery unit 200 is in the constant current charging process, the battery unit 200 changes to the constant voltage charging mode, maintains a constant voltage, for example, adjusts the voltage of the battery to be replaced, and then the battery unit ( 200) Cut off the magnetic contactor, remove the battery and replace it with a new battery.

The reason for changing to the constant voltage charging mode as described above is that the DC / DC converter of the DC load unit 400 continuously supplies a predetermined voltage to the DC load using the voltage.

In addition, matching to a predetermined voltage, in particular, the voltage of the battery to be replaced is a large current according to the voltage difference is a DC / DC of the battery unit 210 and the battery unit 200 when the battery voltage and the predetermined predetermined voltage difference It is preferable to do this as it may occur between converters.

When the battery replacement is completed through the step (S63), the manager inputs the battery replacement completion through the control unit 500, the present invention switches to the above-mentioned day, night operation mode.

100: solar cell unit. 110: solar cell unit.
120: solar cell breaker. 200: battery unit.
210: battery unit. 220: battery breaker.
230: battery switch. 300: DC link section.
310: power conversion unit. 400: DC load part.
500: control unit.

Claims (11)

Solar cell unit including one or more solar cells; A solar cell unit controlling power generated by the solar cell unit and including a DC / DC converter; A solar cell breaker installed between the solar cell unit and the solar cell unit; A DC link unit installed between the solar cell unit and the power system; A power converter installed between the DC link unit and the power system and including a DC / AC bidirectional power converter; A battery unit capable of storing electrical energy, including one or more batteries; A battery unit which controls the charging of the battery unit, is connected to the solar cell unit and the power conversion unit using the DC link unit as a contact point, and includes a DC / DC converter; A battery breaker and a battery switch installed between the battery unit and the battery unit; A DC load unit installed between the battery unit and the DC load, the DC load unit including a DC / DC converter to supply DC power to the DC load; And for supplying power to the DC load and charging the battery using a photovoltaic energy storage system including a control unit for controlling the operation of the solar cell unit, battery unit, DC link unit, power conversion unit and DC load unit As a control method of the solar energy storage system,
System status check step (S1) to check the overall system status of the photovoltaic energy storage system; And when the whole system is normal in the step (S1), if the control unit determines that the current time (t) exceeds the daytime boundary time (td) and falls within the range of less than the night boundary time (tn) the current time (t) If it is determined that it belongs to the daytime, and the range is out of the above range, the day and night judgment step (S2) to determine that the current time (t) belongs to the night,
If it is determined in step S2 that the current time t belongs to daytime, the controller operates the solar energy storage system of the present invention in a daytime operation mode step S31; After the step S31, the controller performs a charging state checking step S32 of checking the charging state of the battery unit.
In the step S32, when the state of charge of the battery in the battery unit is a low voltage or an overvoltage state, the battery remaining scenario mode S5 is executed, and in the step S32, the state of charge of the battery in the battery unit is a normal voltage. By performing the operation mode determination step (S33) of measuring the voltage (PV) of the electrical energy produced by the solar cell unit to determine the operation of the solar cell unit,
In the step S33, if the initial operating voltage PVr exceeds 150 V, which is an operation start voltage, or the current voltage PV is within a range of more than 100 V and less than 500 V, which is an operation holding voltage range, the system state checking step S1 is performed. In operation S33, when the initial operation voltage PVr is 150 V or less or the current voltage PV is out of the operation maintenance voltage range, an operation standby mode S34 for stopping power generation of the solar cell unit is performed. After the step S34, the day and night determination step S2 is performed.
If the current time (t) is determined to belong to the night in the step (S2), the night operation mode step (S41) for the control unit to operate the photovoltaic energy storage system of the present invention at night operation; After the step S41, the controller performs a charging state checking step S42 of checking a charging state of the battery unit.
In the step S42, when the state of charge of the battery in the battery unit is a low voltage or an overvoltage state, the battery remaining scenario mode S5 is executed, and in the step S42, the state of charge of the battery in the battery unit is a normal voltage. The system status checking step (S1) is carried out,
A charge state checking step (S321) of determining whether a charge state value (soc) of the battery can be checked in order to check the charge state of the battery when the charge state checking steps (S32, S42) are started;
If it is possible to check the state of charge (soc) in the step (S321), the soc check step of comparing the state of charge (soc) with the minimum allowable soc value (soc_mi), the maximum allowable soc value (soc_mx) in advance ( S322);
In the step S322, when the state of charge value soc is less than the minimum allowable soc value soc_mi or less than the maximum allowable soc value soc_mx, it is determined that the state of charge of the battery is normal and the normal voltage determination step S324 is performed. To terminate the charging state checking step (S32, S42),
In the step S322, when the state of charge value soc is less than the minimum allowable soc value soc_mi or exceeds the maximum allowable soc value soc_mx, the battery level remaining scenario scenario S5 is performed.
If the state of charge (soc) is impossible to check in step S321, the battery voltage check comparing the voltage value BV of the battery with the minimum allowable voltage value BV_mi and the maximum allowable voltage value BV_mx previously inputted. Step S323;
In operation S323, when the battery voltage value BV is greater than the minimum allowable voltage value BV_mi and less than the maximum allowable voltage value BV_mx, it is determined that the state of charge of the battery is normal and the normal voltage determination step S324 is performed. To terminate the charging state checking step (S32, S42),
In the step S323, when the battery voltage value BV is less than the minimum allowable voltage value BV_mi or more than the maximum allowable voltage value BV_mx, the remaining battery capacity scenario step S5 may be performed. Control method of solar energy storage system. delete The method of claim 1, wherein in step S31, the DC / DC converter in the solar cell unit is operated in a maximum power point following mode, and the DC / AC power converter in the power converter is operated in an inverter mode. The control method of the solar energy storage system. The method according to claim 1, wherein in step S41, the DC / AC power converter in the power converter is operated in a converter mode, and the grid current reference value of the DC link unit is a negative value. Control method of photovoltaic energy storage system. The method according to claim 1, wherein in the step S31 and the step S41, supplying the DC power to the DC load is the battery unit. delete The method of claim 1, wherein the battery remaining scenario mode S5 is started.
A battery voltage determination step of determining whether the battery in the battery unit is undervoltage or overvoltage (S51);
In the step S51, if it is determined that the batteries in the battery unit is a low voltage state, the low voltage warning step (S52) of the control unit to inform the user that the battery is in a low voltage state;
A battery low voltage state checking step (S53) of checking a low voltage state of the battery after the step (S52);
In operation S53, when the current battery voltage value BV is lower than the previously input limit allowable voltage value BV_lim and the charging count cn is higher than the maximum charge count value cmx previously input, the battery low voltage error. After the notification step (S55) is carried out the system status check step (S1),
When the current battery voltage value BV is equal to or higher than the limit allowable voltage value BV_lim previously input in the step S53 or the charge count cn is equal to or smaller than the maximum charge count cmx previously input. To perform the charging step (S54) for charging the multi-sided battery,
In the step S51, if it is determined that the batteries in the battery unit are in an overvoltage state, the control unit notifies the user that the battery is in an overvoltage state (S56);
After the step (S56), after performing the battery charge stop step (S57) for blocking the charge to the battery unit 210, and performing the battery voltage determination step (S51), of the solar energy storage system Control method. The method of claim 7, wherein
When the charging step (S54) is carried out while charging the battery unit, comparing the charging time (ct) measured while starting to charge exceeds 2 hours, the charging time (ct) is 2 hours The charging method of the solar energy storage system, characterized in that to charge the battery until it exceeds this. The method of claim 7, wherein
After charging the battery unit according to the charging step (S54), the battery charge state value (soc) exceeds the previously input charge allowable soc value (soc_ps) or the battery voltage value (BV) is rated voltage If the value RV is exceeded, the system status checking step S1 is performed.
After charging the battery unit according to the step (S54), the battery charge state value (soc) is equal to or less than the previously input charge allowable soc value (soc_ps) and the battery voltage value (BV) is the rated voltage value (RV Or less), adding one to the current charging count (cn) and performing the step (S53). Solar cell unit including one or more solar cells; A solar cell unit controlling power generated by the solar cell unit and including a DC / DC converter; A solar cell breaker installed between the solar cell unit and the solar cell unit; A DC link unit installed between the solar cell unit and the power system; A power converter installed between the DC link unit and the power system and including a DC / AC bidirectional power converter; A battery unit capable of storing electrical energy, including one or more batteries; A battery unit which controls the charging of the battery unit, is connected to the solar cell unit and the power conversion unit using the DC link unit as a contact point, and includes a DC / DC converter; A battery breaker and a battery switch installed between the battery unit and the battery unit; A DC load unit installed between the battery unit and the DC load, the DC load unit including a DC / DC converter to supply DC power to the DC load; And for supplying power to the DC load and charging the battery using a photovoltaic energy storage system including a control unit for controlling the operation of the solar cell unit, battery unit, DC link unit, power conversion unit and DC load unit As a method of replacing the battery in the battery unit of the solar energy storage system,
A battery replacement setting step (S61) in which the controller is set to a battery replacement mode;
In the step (S61), when the solar energy storage system of the present invention is operated in the daytime operation mode night operation mode change step (S62) for changing to the night operation mode;
When the step S62 is performed or when it is determined in the night operation mode in step S61, the DC / DC converter in the battery unit is changed to the constant voltage charging mode to maintain a constant voltage and then the magnetic contactor in the battery unit. Battery replacement step (S63) to replace the battery by blocking the;
And after the step (S63) is finished, the controller releases the battery replacement mode. delete

Images