KR101255470B1 - Battery Energy Storage System - Google Patents

Abstract

An energy storage system according to an embodiment of the present invention includes a battery, a charging unit for charging the battery using the energy supplied from any one of the power supply means of the grid power means and solar power means; A first switch unit for regulating an output of energy charged in a battery of the charging unit; An inverter unit configured to supply energy charged in a battery of the charger unit to a load based on a switching operation of the first switch unit; Determine at least one of a power supply means for charging the battery and a power supply means for operating the load according to a preset condition, and to perform charging and operation of the load by the determined power supply means. It includes an energy management unit for controlling.

Description

Energy Storage System {Battery Energy Storage System}

The present invention relates to an energy storage system, and more particularly, to an energy storage system capable of preventing energy inflow into a system while using energy efficiently.

In general, an uninterruptible power supply (UPS) is composed of a rectifier for converting AC power into DC power, a charger for charging a battery with DC power, a battery for charging DC power, and an inverter for converting DC power to AC power. Normally, it converts commercial AC power into DC to charge the battery, and when the power goes out, it converts the DC power of the battery into AC power and supplies the power even in the event of power failure. The uninterruptible power supply is widely used as an emergency power source for important devices such as computers or emergency lamps.

Meanwhile, as people's living standards increase and the quality of life improves, household appliances with high power consumption such as TVs, refrigerators, washing machines, etc., as well as air conditioners and electric heating devices are widely used. Consumption is skyrocketing. As it takes a lot of money to build a new power plant to meet the rapidly increasing demand for electricity, it analyzes the power demand pattern and adopts a method to differentiate the electricity rate by dividing the late night time zones with low power consumption and the day time zones with high power consumption. This is to suppress the use of electricity during the daytime period.

1 is a basic circuit diagram of a solar inverter according to the prior art, Figure 2 is a block diagram of an uninterruptible power supply using a solar inverter.

Referring to FIG. 1, a solar inverter according to the related art uses an LC filter at an output stage to reduce ripple and harmonic components of an output power. Since the PV module supplies a variable voltage between 100 and 400 V according to the environment, the inverter maintains a constant DC link input voltage (Vdc) at the DC voltage required for the grid voltage using a DC-DC converter. Make sure to supply stable voltage.

In addition, referring to FIG. 2, an uninterruptible power supply is conventionally constructed using the above-described solar inverter.

That is, the conventional technology can supply energy to the grid using a solar inverter, or charge energy when there is a battery in the inverter and do not generate power, and cope with an abnormal situation with energy charged in the battery using the inverter. Make sure In addition, as described above, since the conventional technology supplies energy only to a load, a thyristor circuit is provided so that energy does not flow into the system.

However, the uninterruptible power supply according to the prior art has a problem in that it is not possible to efficiently use the charged energy as described above by using only the energy charged using the solar inverter in an emergency situation.

In addition, there is a problem in that energy use is made inefficient by using all the energy charged in the battery regardless of the energy required for the load in a simple power generation form.

In an embodiment according to the present invention, a plurality of power means is used to charge energy in a battery at night time, and to efficiently use the charged energy in a time when power consumption is high.

In addition, in the embodiment according to the present invention to prevent the energy generated by the reverse algae flow into the system in advance.

The technical problems to be achieved in the proposed embodiment are not limited to the technical problems mentioned above, and other technical problems not mentioned above are clear to those skilled in the art to which the proposed embodiments belong from the following description. Can be understood.

An energy storage system according to an embodiment of the present invention includes a battery, a charging unit for charging the battery using the energy supplied from any one of the power supply means of the grid power means and solar power means; A first switch unit for regulating an output of energy charged in a battery of the charging unit; An inverter unit configured to supply energy charged in a battery of the charger unit to a load based on a switching operation of the first switch unit; Determine at least one of a power supply means for charging the battery and a power supply means for operating the load according to a preset condition, and to perform charging and operation of the load by the determined power supply means. It includes an energy management unit for controlling.

The apparatus may further include a second switch unit formed between the power supply unit and the load to regulate energy supplied from the power supply unit. On, and at a second time, the second switch unit is turned on to determine the power supply means for operating the load.

The first time is an occurrence of power failure, and the second time is a remaining time except for the first time.

The first time is a maximum demand power time zone, and the second time is a time remaining except for the first time.

The apparatus may further include a third switch unit formed between the grid power unit and the solar power unit and the charging device to regulate energy supplied to the battery, wherein the energy management unit is configured to perform the control at a third time according to a preset condition. The charging operation is performed by a system power means, and the switching operation of the third switch unit is controlled to perform the charging operation by the solar power means at a fourth time.

The third time may include at least one of a normal operation time of the grid power means and an abnormal operation time of the solar power means, and the fourth time may be an abnormal operation time of the grid power means and the solar power. At least one of the normal starting points of the means.

In addition, the third time includes a late night time having a low energy price, and the fourth time includes a power failure occurrence time.

The energy management unit may determine a target command value based on the load current amount according to the energy supplied to the load, and control the output energy of the inverter unit to follow the target command value.

The target command value is lower than the load current amount.

According to an embodiment of the present invention, by using the energy charged in the time when the energy is the cheapest during the time of high energy consumption, the power can be used efficiently, effectively preventing the energy generated by the reverse current control flow into the system can do.

1 is a basic circuit diagram of a solar inverter according to the prior art.
2 is a configuration diagram of an uninterruptible power supply using a solar inverter.
3 is a view showing the configuration of the energy storage system according to an embodiment of the present invention.
4 is a view for explaining a reverse algae control process according to an embodiment of the present invention.
5 to 7 are flowcharts for explaining a step-by-step operation method of the energy storage system according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

3 is a view showing the configuration of the energy storage system according to an embodiment of the present invention.

Referring to FIG. 3, the energy storage system includes a solar power means 100, a grid power means 200, a load 300 and an uninterruptible power supply 400.

The solar power means 100 receives sunlight to generate a predetermined energy.

To this end, the solar power means 100 includes a solar cell module (solar cell), the solar cell module generates energy from the solar light, the energy is loaded by a separate photovoltaic inverter The energy is converted into energy suitable for the 300 or the battery 410.

Here, the solar cell module is configured to array a plurality of solar cells using amorphous silicon, crystalline silicon, or compound semiconductors in order to obtain a predetermined output voltage and current. The power conversion unit included in the solar power means 100 includes a magnet such as a power transistor, a power MOSFET, Insulated gatebipolar transistors (IGBT), or a gate turn-off thyristors (GTO). It may be a DC / DC converter or a voltage-fed self-excited inverter using a self turn-off switching device.

The energy (power, voltage, frequency, etc.) output by the solar power means 100 can be controlled by changing the on / off duty of the gate pulse supplied to the switching device of the power converter.

The system power means 200 is a system power means and provides a commercial AC power source.

An example of the load 300 is an electric heater or an electric motor or a commercial AC power system. If the load 300 is a commercial AC power system, i.e. a grid connection photovoltaic system, the power of the photovoltaic system that can be put into the commercial AC power system is not limited, and thus this configuration Is extremely preferred in the case of extracting a large amount of energy from the solar power means 100.

The uninterruptible power supply 400 is charged by energy supplied from the solar power means 100 or the grid power means 200, and optionally supplies energy of the grid power means 200 to the load 300. Alternatively, after cutting off the energy supplied through the system power means 200, the energy charged in the battery 410 is supplied to the load 300.

Hereinafter, the uninterruptible power supply 400 will be described in more detail.

The uninterruptible power supply 400 includes a battery 410, a charger 420, a first switch 430, an inverter 440, a second switch 450, and a third switch ( 460, a current detector 470, and a battery management system (BMS) 480.

The battery 410 stores the energy supplied through the solar power means 100 or the grid power means 200.

The charger 420 charges the battery 410 using energy supplied through the solar power means 100 or the grid power means 200.

That is, the battery 410 and the charger 420 are charging devices that perform charging operation using commercial AC power or solar power.

The first switch 430 intercepts the energy charged in the battery 410. That is, the first switch 430 performs an on / off operation by the control of the energy manager 480 which will be described later, thereby providing the load 300 with the energy charged in the battery 410.

The inverter 440 converts the energy stored in the battery 410 into energy suitable for the load 300 and outputs the energy. For example, the inverter 440 may convert DC power into AC power and output the AC power.

The second switch 450 is formed between the solar power means 100 and the grid power means 200 and the load 300, and performs a switching operation under the control of the energy management unit 480, which will be described later. Energy supplied through the solar power means 100 and the grid power means 200 is selectively supplied to the load 300.

The third switch 460 is selectively connected to the output line of the energy supplied through the solar power means 100 and the output line of the energy supplied through the grid power means 200, the battery 410 Select the energy to charge.

For example, the third switch 460 is connected to an energy output line of the solar power means 100 and supplied from the solar power means 100 by the control of the energy management unit 480 which will be described later. The battery 410 is charged with the energy.

In addition, the third switch 460 is connected to the energy output line of the grid power means 200 by the control of the energy management unit 480, the battery 410 by the energy supplied from the grid power means 200 ) To be charged.

The current transformer CT 470 detects the current amount of the load 300, and transfers the detected load current amount to the energy management unit 480.

The energy manager 480 controls the overall operation of the uninterruptible power supply 400.

In particular, the energy manager 480 controls the first switch 430 according to a preset time so that the energy charged in the battery 410 is supplied to the load 300. In this case, when the first switch 430 is turned on, the energy manager 480 turns off the second switch 450 so that the energy charged in the battery 410 is loaded in the load ( 300).

In addition, the energy manager 480 turns off the first switch 430 and turns on the second switch 450 so that the energy supplied through the solar power means 100 or the grid power means 200 is reduced. To be supplied to the load 300.

In addition, the energy management unit 480 controls the third switch 460 according to the time zone, charging the battery 410 according to the energy supplied through the solar power means 100 or the grid power means 200. Let this be done.

In addition, the energy management unit 480 controls the output value of the inverter 440 based on the load current amount detected through the current detection unit 470, so that the energy is transferred to the grid power means 200 in accordance with the prevention of reverse currents. To prevent ingress.

4 is a view for explaining the reverse current control.

That is, the energy management unit 480 performs the reverse current control to output only the amount of energy used by the load 300 through the inverter 440.

To this end, the energy manager 480 sets a reference value I * out of the output current. The reference value (I * out) of the output current may be set by the following method.

ILoad: Load Current

a: constant less than 1

As shown in Equation 1, I * out may be set by multiplying ILoad by a constant a value. At this time, since the constant a has a value less than 1, I * out is set to a value less than ILoad. For example, the constant a may be set to 0.95. When the load current amount is 1, the reference value of the output current is set to 0.95 which is smaller than the load current amount 1.

Next, the energy manager 480 detects an output value Iout currently output through the inverter 440.

The energy management unit 480 includes a PI integral controller, and accordingly, the output value of the inverter 440 is equal to the output current by using the reference value of the set output current and the output value of the inverter 440. The target output value of the inverter 440 is reset to follow the reference value of.

Accordingly, the output value of the inverter 440 corresponds to the energy required by the load 300, thereby not only efficiently using the energy stored in the battery 410, but also generating the system power means. Can be prevented from entering.

5 to 7 are flowcharts for explaining a step-by-step operation method of the energy storage system according to an embodiment of the present invention. Hereinafter, a description of the operation method illustrated in FIGS. 5 to 7 will be described with reference to the system illustrated in FIG. 3.

5 is a flowchart illustrating a step-by-step method of supplying energy to a load according to an embodiment of the present invention.

Referring to FIG. 5, first, energy supplied through the system power means 200 is supplied to the load 300 at a second time (step 100). In this case, the second time may generally be a normal time when the grid power means 200 is operating.

The energy manager 480 determines whether the first predetermined time has arrived in the situation where the energy supplied through the grid power means 200 is being supplied to the load 300 (step 110).

In this case, the first time and the second time may be defined as follows.

The first time may be a time when a power failure occurs, that is, a time when the system power means 200 is not normally driven.

In addition, the second time may be a time other than the first time (time when power failure occurs).

In another embodiment, the first time may be a maximum demand power time, and the second time may be a time other than the first time (maximum demand power time). Herein, the maximum demand power time may be a time when energy consumption is greatest, for example, day time.

The energy manager 480 turns on the first switch 430 and turns off the second switch 450 according to the determination result (step 110), when the first time arrives.

That is, when the first time arrives, the energy manager 480 cuts off the energy supplied through the grid power means 200, and accordingly outputs the energy charged in the battery 410.

First switch 2nd switch 1st time On off 2nd time off On

That is, as shown in Table 1, the energy management unit 480 maintains the on state of the second switch 450 at the second time, and when the first time arrives, the second switch 450 is turned off. , The first switch 430 is turned on.

Accordingly, the energy manager 480 allows the energy charged in the battery 410 to be supplied to the load 300 (step 130).

6 is a flowchart illustrating a step-by-step method of charging a battery according to an embodiment of the present invention.

Referring to FIG. 6, first, the energy manager 480 may supply energy supplied through the solar power means 100 to the battery 410 to charge the battery 410 (step 210). In this case, the time at which the battery 410 is charged with the energy supplied through the solar power means 100 may be referred to as a second time.

The energy manager 480 determines whether the first time has come while the battery 410 is being charged (S220).

In this case, the first time and the second time may be defined as follows.

The first time may be a time when the solar power means 100 is not normally driven, and the second time may be a time when the solar power means 100 is normally driven. For example, the first time may be a night time zone. In addition, the night time zone is a time when the power unit price is relatively low, and thus the night time zone to charge the battery 410 with the energy supplied through the solar power means 100.

Alternatively, the first time may be a time at which the system power means 200 is normally driven, and the second time may be a time at which the system power means 200 is not normally driven. For example, the second time may be a time when a power failure occurs, and when the power failure occurs, the battery 410 is charged by using the solar power means 100, and at other times, the system power means 200. ) May be used to charge the battery 410.

The energy management unit 480 changes the connection state of the third switch 460 when the first time arrives, such that energy supplied through the system power means 200 is supplied to the battery 410. The battery 410 is charged by the energy of the grid power means 200 (step 230 and step 240).

7 is a flowchart illustrating a step-by-step algae control method according to an embodiment of the present invention.

Referring to FIG. 7, the current detector 470 detects a current amount of the load 300 and transfers the detected current amount to the energy manager 480 (step 310).

The energy manager 480 sets a target current amount using the transferred charge current amount in step 320. In this case, the target current amount may be obtained by multiplying the charge current amount by a constant smaller than one. Accordingly, the target current amount may have a smaller value than the charge current amount.

The energy manager 480 detects an output value currently output through the inverter 440 (step 330).

Subsequently, the energy manager 480 resets the target output value of the inverter 440 so that the detected inverter 440 output value follows the obtained target current amount, and the inverter 440 is reset to the reset target output value. The output value of the control to come out (step 340).

As described above, according to the embodiment of the present invention, by using the energy charged at the time when energy is the cheapest during the time when the energy consumption is high, the power can be efficiently used, and the energy generated through the reverse current control is introduced into the system. Can be effectively prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications other than those described above are possible.

100: solar power means
200: grid power means
300: load
400: uninterruptible power supply

Claims (9)

A charging unit including a battery and charging the battery using energy supplied from any one of a system power means and a solar power means;
A first switch unit for regulating an output of energy charged in a battery of the charging unit;
An inverter unit configured to supply energy charged in a battery of the charger unit to a load based on a switching operation of the first switch unit;
Determining power supply means for charging the battery and power supply means for operating the load, controlling the charging and operation of the load to be performed by the determined power supply means, and charging the battery It includes an energy management unit for checking the predetermined condition for the determination of the power supply means for controlling the charging of the battery by the power supply means of a condition corresponding to the current time point,
The energy management unit
And a target command value lower than the load current amount based on the load current amount according to the energy supplied to the load, and output energy of the inverter unit is adjusted by the determined target command value. The method of claim 1,
A second switch unit formed between the power supply unit and the load to regulate energy supplied from the power supply unit,
And the energy management unit determines the power supply means for operating the load by turning on the first switch unit at a first time and turning on the second switch unit at a second time according to the set condition. The method of claim 2,
The first time is a power failure occurrence time,
And wherein the second time is a time other than the first time. The method of claim 2,
The first time is the maximum demand power time zone,
And wherein the second time is a time other than the first time. The method of claim 1,
A third switch unit formed between the grid power unit and the solar power unit and the charging unit to regulate energy supplied to the battery,
The third switch is configured to charge the battery by the grid power means at a third time and to charge the battery by the solar power means at a fourth time according to a preset condition. Energy storage system to control the switching operation of the negative. 6. The method of claim 5,
The third time includes at least one of a normal operation time of the grid power means and an abnormal operation time of the solar power means,
And said fourth time period comprises at least one of an abnormal start time of said grid power means and a normal start time of said solar power means. 6. The method of claim 5,
The third time includes a late night time with a low energy price;
And said fourth time comprises an outage time. delete delete

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