KR102207402B1 - Power conditioning system and Energy storage system - Google Patents

Abstract

A power conversion device according to an embodiment includes a power storage unit for charging a voltage from a system; A conversion unit for converting a voltage between the system and a power storage unit; And a control unit that measures the voltage of the system and controls the operation of the system, the power storage unit, and the conversion unit.

Description

Power conditioning system and energy storage system

The embodiment relates to a power conversion device.

The embodiment relates to an energy storage system.

A typical ESS (Energy Storage System) device charges when the demand for power is low on the system side, and when the demand for power is high, it discharges the power supply to supply power to the system. It has the role of stabilizing power by instantaneous correction.

Power conditioning system (PCS) included in these ESS devices is a conversion unit that receives power from the grid and converts it into DC power, converts the received DC power to AC power, and delivers it to the grid and the load, and a battery. And a power storage unit for supplying DC power of the DC power to the conversion unit, and a control unit for controlling switches of the system, the conversion unit and the power storage unit.

In the conventional ESS device, a device that monitors the power state of a system is essential to determine the demand for power, but there are problems such as cost problems to build the monitoring device alone.

The embodiment provides a power conversion device and an energy storage system capable of efficiently storing and generating power.

A power conversion device according to an embodiment includes a power storage unit for charging a voltage from a system; A conversion unit for converting a voltage between the system and a power storage unit; And a control unit that measures the voltage of the system and controls the operation of the system, the power storage unit, and the conversion unit.

An energy storage system according to an embodiment includes a system for supplying power; A load consuming the power; A power conversion device that stores power from the system or supplies the stored power to the load or system, wherein the power conversion device measures a voltage of the system and controls the operation of the system and the power conversion device. Includes.

The power conversion device according to the embodiment may control power storage and power generation by measuring an output voltage of a system and predicting a consumption pattern of a load, thereby increasing energy storage and power generation efficiency with a simple configuration.

The energy storage system according to the embodiment may increase energy storage and power generation efficiency by controlling power storage and power generation through a voltage average for each time period and a predicted solar cell generation amount.

1 is a block diagram showing an energy storage system according to a first embodiment.
2 is a block diagram showing a power conversion device according to the first embodiment.
3 is a block diagram showing a control unit according to the first embodiment.
4 is a circuit diagram showing a connection relationship between a power conversion device and a system according to the first embodiment.
5 is a flow chart showing the operation of the power conversion device according to the first embodiment.
6 is a block diagram showing an energy storage system according to a second embodiment.
7 is a block diagram showing a control unit according to the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the embodiments of the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and similar reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element interposed therebetween. .

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated. In addition, terms such as "... unit", "... group", and "module" described in the specification mean units that process at least one function or operation, which can be implemented by hardware or software or a combination of hardware and software. have.

Referring to FIG. 1, the energy storage system according to the first embodiment may include a system 10, a load 20, a power conversion device 30, and a switch 40.

The system 10 may be connected to the load 20 and the power conversion device 30. The system 10 may be connected to the load 20 and the power conversion device 30 through a wiring 45.

The system 10 delivers power to the load 20 and the power conversion device 30. The system 10 may supply power required for consumption of the load 20 and may deliver power required for charging the power conversion device 30. In addition, the system 10 is a system that provides the power conversion device 30 with various information necessary for determining charging or discharging of the power conversion device 30 and information necessary for calculating an electric charge to the power conversion device 30. It may include. The system 10 may include various management servers for managing electricity usage and electricity bills. The system 10 may be a vehicle, a solar cell, or a household power storage system.

The load 20 may receive power from the system 10 or the power conversion device 30 and consume it. The load 20 may receive power from the system 10 when the switch 40 is short-circuited, and may receive power from the power conversion device 30 when the switch 40 is open.

The power conversion device 30 measures the voltage of the wiring 45 applied from the system 10 to the load 20 and generates electricity from the system 10 based on the voltage of the wiring 45. Purchased and stored in the power conversion device 30, or the stored electricity may be sold to the system 10. In addition, the power conversion device 30 may supply charged electricity to the load 20.

The power conversion device 30 is information necessary for charging/discharging electricity through various communication methods including wired or wireless communication methods and power line communication (PLC) methods with the system 10 and the load 20 Can transmit or receive each other.

In the above embodiment, the charging/discharging control of the power conversion device 30 and the determination of the power delivery subject to the load 20 by the power conversion device 30 were exemplified. Power delivery judgment can be made. In this case, the power conversion device 30 may perform charging and discharging under the control of the controller.

Referring to FIG. 2, the power conversion device 30 according to the embodiment may be connected to the system 10 by a wiring 45.

The power conversion device 30 may include a control unit 100, a filter unit 110, a conversion unit 120, a boost/decompression unit 130, and a power storage unit 140.

The power conversion device 30 stores the AC input power delivered to the system 10 under the control of the control unit 100 in the power storage unit 140, and when necessary, for example, the AC input power is cut off. In this case, electric power may be generated from the power storage unit 140 in the direction of the system 10.

The control unit 100 may apply a control signal for controlling the filter unit 110, the conversion unit 120, the boost/decompression unit 130, and the power supply unit 150 in each configuration. The control unit 100 may control charging and discharging between the system 10 and the power storage unit 140.

The controller 100 may measure the voltage of the wiring 45 and control charging/discharging between the system 10 and the power conversion device 30 according to the voltage of the wiring 45. The control unit 100 may control charging/discharging between the system 10 and the power storage unit 140 according to the voltage of the wiring 45.

The control unit 100 may control operations of the filter unit 110, the conversion unit 120, the boost/decompression unit 130, and the power supply unit 150. The control unit 100 may control the operation of the power conversion device 30 by controlling a switch included in each component of the power conversion device 30.

The filter unit 110 may filter noise and surge voltage generated from an output or input AC power of the system 10 or the conversion unit 120. The filter unit 110 may operate as a bidirectional filter.

The conversion unit 120 is a two-way converter, and when the power storage unit 140 is charged from the system 10, it rectifies and smoothes the input AC power and transfers it to the boost/depressor 130, and the power storage unit During power generation of 140, the DC voltage of the power storage unit 140 may be converted to AC and transmitted to the system 10 through the filter unit 110. In other words, the conversion unit 120 may convert an AC voltage to a DC voltage and convert the DC voltage to an AC voltage.

The boost/decompression unit 130 may reduce the DC voltage supplied from the conversion unit 120 to a level that can be stored by the power storage unit 140 and transmit it to the power storage unit 140. The boost/decrease unit 130 may boost the DC voltage supplied from the power storage unit 140 and transmit it to the conversion unit 120.

The power storage unit 140 may be a battery. The power storage unit 140 may store a DC voltage transmitted from the system 10 through the boost/depressor 130 and output the stored DC voltage according to a control signal from the control unit 100. .

Referring to FIG. 3, the control unit 100 according to the first embodiment may include a voltage measurement unit 101, an operation unit 103, and a storage unit 105.

The voltage measuring unit 101 may measure the voltage of the wiring 45. The voltage measurement unit 101 may measure the voltage of the wiring 45 and transmit the measured voltage to the operation unit 103. The voltage measuring unit 101 may measure the voltage of the wiring 45 at a constant time interval.

The calculation unit 103 may calculate an average of the voltages of the wiring 45 received from the voltage measurement unit 101 and store them in the storage unit 105. The calculation unit 103 may calculate the average of the voltages for each time period and store them in the storage unit 105.

The operation unit 103 may select a driving method profile of the load 20 using the voltage average for each time period. The driving mode profile is previously stored in the storage unit 105. The calculating unit 103 may select the driving method profile of the load 20 by comparing the voltage average for each time period with the driving method profile stored in the storage unit 105. The driving mode profile may be domestic, commercial or industrial. That is, the operation unit 103 may determine whether the load 20 corresponds to any one of household, commercial, and industrial use, using the voltage average for each time period. The operation unit 103 includes the filter unit 110, the conversion unit 120, the boost/depression unit 130, and the power supply unit 150 to match the characteristics of the load 20 according to the type of the load 20. You can control the operation.

The calculation unit 103 includes a measurement time of the voltage of the wiring 45 among the voltage of the wiring 45 measured by the voltage measuring unit 101 and a voltage average for each time period stored in the storage unit 105 Charging and discharging between the system 10 and the power conversion device 30 may be controlled by comparing the voltage average of the same time period.

The operation unit 103 compares the voltage of the wiring 45 and the average of the voltage, and operates the filter unit 110, the conversion unit 120, the boost/depression unit 130, and the power supply unit 150 according to the result. Can be controlled. The operation unit 103 may compare the voltage of the wiring 45 with the average of the voltage and control the operation of the switch 40 according to the result.

The storage unit 105 may store a voltage average for each time period received from the operation unit 103 as a reference value. The reference value may be an average of voltages measured by the voltage measuring unit 101. Also, the reference value may be separately input from an external device.

A driving method profile of the load 20 may be stored in the storage unit 105. The driving mode profile may be domestic, commercial or industrial. The driving mode profile may be a charge/discharge flow according to the type of the load 20.

The operation unit 103 may control the load 20 to use the voltage of the system 40 when the voltage of the wiring 45 is greater than the average voltage stored in the storage unit 105. The operation unit 103 may control the voltage of the system 40 to be applied to the load 20 by shorting the switch 40.

Alternatively, the operation unit 103 may control the voltage of the system 10 to be charged to the power storage unit 140 when the voltage of the wiring 45 is greater than the average value of the voltage stored in the storage unit 105. The operation unit 103 short-circuits the switch 40 and controls the filter unit 110, the conversion unit 120, the boost/depression unit 130, and the power supply unit 150 so that the power storage unit 140 is charged. By doing so, the voltage of the system 10 can be charged to the power storage unit 140.

The operation unit 103 may control the voltage of the power storage unit 140 to be discharged when the voltage of the wiring 45 is less than the average value of the voltage stored in the storage unit 105.

The operation unit 103 may control the voltage of the power storage unit 140 to be transmitted to the load 20 when the voltage of the wiring 45 is less than the average value of the voltage stored in the storage unit 105. Alternatively, the operation unit 103 may transfer the voltage of the power storage unit 140 to the system 10 when the voltage of the wiring 45 is less than the average value of the voltage stored in the storage unit 105. The power conversion device 30 may sell stored electricity by applying a voltage to the system 10.

When the power is insufficient, the voltage of the system 10 decreases, and when the power is sufficient, the voltage rises, and the system 10 has a different sales amount depending on the excess or lack of power, so the voltage of the system 10 decreases. In this case, since the power of the system 10 is insufficient, electricity is sold from the power conversion device 30 to the system 10, or the voltage charged in the storage battery of the power conversion device 30 is transferred to the load. It can be consumed by approving it with (20). In addition, when the voltage of the system 10 rises, since the power of the system 10 is sufficient, the voltage of the system 10 may be applied to the load 20 and consumed, or the system ( The voltage of 10) may be charged by the power storage unit 140 of the power conversion device 30.

The control unit 100 has an effect of efficiently storing and consuming power by controlling charging and discharging between the system 10 and the power conversion device 30 with the output voltage of the system 10.

In addition, since the control unit 100 controls charging and discharging by measuring the voltage of the wiring 45, which is relatively easy to measure, power fluctuations are measured without establishing a separate energy management system, thereby charging and discharging. Has the effect of being able to control it.

Referring to FIG. 4, the power conversion device according to the first embodiment may include a filter unit 110, a conversion unit 120, a boost/decrease unit 130, and a power storage unit 140.

The system 10 may be electrically connected to the filter unit 110 through a wiring 45.

The control unit 100 may sense the voltage across the system 10. The control unit 100 may measure the voltage of the wiring 45.

The filter unit 110 may include first to fourth inductors L1 to L4 and a capacitor C.

The first inductor L1 may be connected in series with the third inductor L3, and the second inductor L2 may be connected in series with the fourth inductor L4. The capacitor C may connect between the first and third inductors L1 and L3 and between the second and fourth inductors L2 and L4.

The filter unit 110 including the first to fourth inductors (L1 to L4) and the capacitor (C) is a noise and static electricity that may occur when storing an AC voltage from the system 10 to the power storage unit 140 And filtering out static electricity that may occur when a voltage is output from the power storage unit 140 to the system 10.

The conversion unit 120 may include first to fourth transistors Q1 to Q4, first to fourth diodes D1 to D4, and a connection capacitor Clink.

The first to fourth transistors Q1 to Q4 and the first to fourth diodes D1 to D4 may form a bridge between the first and second nodes N1 and N2.

The first to fourth transistors Q1 to Q4 may be controlled by first to fourth signals S1 to S4, respectively. The first to fourth transistors Q1 to Q4 may be connected in parallel with the first to fourth diodes D1 to D4, respectively. The first to fourth signals S1 to S6 may be applied from the control unit 100.

The first transistor Q1 and the first diode D1 are connected between the first node N1 and the third node N3, and the second transistor Q2 and the second diode D2 are It may be connected between the first node N1 and the fourth node N4.

The third transistor Q3 and the third diode D3 are connected between the second node N2 and the third node N3, and the fourth transistor Q4 and the fourth diode D4 are the It may be connected between the second node N1 and the fourth node N4.

The third node (N3) is a contact point between the third inductor (L3) and the first and third transistors (Q1, Q3), the fourth node (N4) is the fourth inductor (L4) and the It may be a contact point between the second and third transistors Q2 and Q4.

As the first and fourth transistors Q1 and Q4 operate simultaneously, and the second and third transistors Q2 and Q3 operate simultaneously, the DC voltages of the first and second nodes N1 and N2 are alternating. Converts to a voltage and transmits it to the third and fourth nodes N3 and N4, or converts the AC voltage of the third to fourth nodes N3 to N4 to the DC voltage and converts the first and second nodes ( N1, N2).

The first to fourth diodes D1 to D4 are protection elements of the first to fourth transistors Q1 to Q4 and may block reverse current from flowing.

The connection capacitor Clink may be connected between the first and second nodes N1 and N2. The connection capacitor Clink stores the DC voltage applied from the step-up/decompression unit 130 and transfers it to the first to fourth transistors Q1 to Q4, or the first to fourth transistors Q1 to Q4. The voltage input from) may be smoothed and transferred to the boost/decompression unit 130.

The step-up and reduction unit 130 is between two transistors (Qa, Qb), two diodes (Da, Db) connected in parallel with the transistors (Qa, Qb), and the two transistors (Qa, Qb) It includes an inductor (La) and a capacitor (Ca) to be connected. The boost/decompression unit 130 may reduce the voltage stored in the connection capacitor Clink of the conversion unit 120 and transmit it to the power storage unit 140, and the voltage received from the power storage unit 140 is The voltage may be boosted and applied to the connection capacitor Clink of the conversion unit 120. The two transistors Qa and Qb of the boost/decompression unit 130 may also be controlled by the control unit 100.

Referring to FIG. 5, the power conversion device according to the first embodiment measures the output voltage of the system 10 by the voltage measuring unit 101 of the control unit 100.

The voltage measuring unit 101 may measure the voltage of the wiring 45 connecting the system 10 and the power conversion device 30. The operation unit 103 of the control unit 100 generates a reference value through the voltage of the wiring 45. (S11)

The reference value may be a voltage average for each time period. The operation unit 103 may store the reference value in the storage unit 105.

The reference value may be directly input to the storage unit 105 from outside the operation unit 103. The reference value may be previously stored in the storage unit 105.

The voltage measuring unit 101 measures the voltage of the system 10. (S12)

Since the voltage measuring unit 101 is connected to the wiring 45, the system 10 may measure the voltage of the wiring 45.

The operation unit 103 may compare the voltage of the system 10 measured through the voltage measurement unit 101 with a reference value stored in the storage unit 105. (S15)

When the voltage of the system 10 is greater than a reference value, the control unit 100 may control the voltage of the system 10 to be stored in the power conversion device 30. (S17)

In addition, when the voltage of the system 10 is greater than the reference value, the controller 100 may control the voltage of the system 10 to be supplied to the load 20 and consumed.

When the voltage of the system 10 is less than a reference value, the control unit 100 may control the power conversion device 30 to generate power. (S19)

When the voltage of the system 10 is less than the reference value, the control unit 100 may control the power of the power conversion device 30 to be supplied to and consumed by the load 20. In addition, when the voltage of the system 10 is less than the reference value, the control unit 100 may supply and sell the power stored in the power conversion device 30 to the system 10.

The control unit 100 has an effect of efficiently storing and consuming power by controlling charging and discharging between the system 10 and the power conversion device 30 with the output voltage of the system 10.

An energy storage system according to a second embodiment will be described with reference to FIGS. 6 and 7.

The energy storage system according to the second embodiment is the same as in the first embodiment except that a solar cell is added. Accordingly, in describing the second embodiment, detailed descriptions of the same components as those of the first embodiment are omitted.

Referring to FIG. 6, the energy storage system according to the second embodiment may include a system 10, a load 20, a power conversion device 30, a switch 40, and a solar cell 50.

The system 10 may be connected to the load 20, the power conversion device 30 and the solar cell 50. The system 10 may be connected to the load 20, the power conversion device 30, the solar cell 50, and the wiring 45.

The load 20 may receive power from the system 10, the power conversion device 30, or the solar cell 50 and consume it. The load 20 may receive power from the system 10 when the switch 40 is short-circuited, and may receive power from the power conversion device 30 when the switch 40 is open. In addition, the load 20 may receive power from the solar cell 50 under the control of the controller 100.

The power conversion device 30 measures the voltage of the wiring 45 applied from the system 10 to the load 20 and generates electricity from the system 10 based on the voltage of the wiring 45. Purchased and stored in the power conversion device 30, or the stored electricity may be sold to the system 10. In addition, the power conversion device 30 may supply charged electricity to the load 20.

The power conversion device 30 may control the movement of electricity between the system 10 and the power conversion device 30 through power generated through the solar cell 50.

The power conversion device 30 may store electricity from the solar cell 50 in the power storage unit 140 under the control of the controller 100.

The solar cell 50 may supply power to the system 10, the load 20, and the power conversion device 30. The solar cell 50 generates power to supply power required for consumption of the load 20, and may supply power required for charging the power conversion device 30, and power to the system 10 Can be delivered. The solar cell 50 may transmit power to the system 10, the load 20, or the power conversion device 30 under the control of the controller 100. In the drawings, the solar cell 50 is described as an example, but it may be a renewable energy source other than the solar cell 50.

Referring to FIG. 7, the control unit 200 according to the second embodiment may include a voltage measurement unit 201, an operation unit 203, a storage unit 205, and a communication unit 207.

The voltage measuring unit 201 may measure the voltage of the wiring 45.

The calculation unit 203 may calculate an average of the voltages of the wiring 45 received from the voltage measurement unit 201 and store them in the storage unit 205. The calculation unit 203 may calculate the average of the voltages for each time period and store them in the storage unit 205.

The storage unit 205 may store a voltage average for each time period received from the operation unit 203 as a reference value. Also, the reference value may be separately input from an external device.

The communication unit 207 may be connected to an external network to receive local weather information and transmit it to the operation unit 203. The external network may be an Internet portal site.

The operation unit 203 may predict the amount of power generation of the solar cell 50 using the local weather information. The operation unit 203 may change the reference value through the predicted amount of power generation of the solar cell 50.

For example, when it is predicted that the solar cell 50 generates a lot of power, the operation unit 203 increases the reference value and transfers it from the system 10 to the load 20 or the power conversion device 30 It is possible to reduce the amount of electricity generated, and supply the power stored in the power conversion device 30 and the power generated from the solar cell 50 to the system 10 to be sold.

In addition, when it is predicted that the solar cell 50 generates less power, the operation unit 203 lowers the reference value to reduce the amount of electricity transferred from the system 10 to the load 20 or the power conversion device 30. Can increase

The operation unit 203 predicts the amount of power generation of the solar cell 50 and controls the charge/discharge between the system 10, the power conversion device 30, and the solar cell 50 to promote efficient storage and consumption of power. I can.

Features, structures, effects, and the like described in the above-described embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Accordingly, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

In addition, although the embodiments have been described above, these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention pertains are illustrated above within the scope not departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications that are not available are possible. For example, each component specifically shown in the embodiments can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

10: line
20: load
30: power converter
40: switch
50: solar cell
100, 200: control unit
101, 201: voltage measuring unit
103, 203: operation unit
105, 205: storage unit
110: filter unit
120: conversion unit
130: boost and decompression unit
140: power storage unit
207: communication department

Claims (10)

A power storage unit for charging power transmitted from the system;
A conversion unit disposed between the system and the power storage unit to convert power of the system into electric power that can be charged to the power storage unit, and convert the discharge power from the power storage unit into electric power that can be supplied to the system; And
And a control unit that measures the voltage of the system and controls operations of the system, the power storage unit, and the conversion unit based on the measured voltage,
The control unit,
A voltage measuring unit measuring the voltage of the system;
A storage unit for storing the average voltage for each time period of the system as a reference value; And
Comprising an operation unit for comparing the reference value and the voltage of the system and controlling the operation of the system, the power storage unit and the conversion unit according to the comparison result
The control unit compares the measured voltage of the system and the average voltage of the measured system voltage at the same time period among the average voltage of the system stored in the storage unit for each time period,
When the measured voltage of the grid is greater than the average voltage of the same time period stored in the storage unit, the power of the grid is supplied to the load,
When the measured voltage of the system is less than the average voltage of the same time period stored in the storage unit, the power charged in the power storage unit is supplied to the load to control charging and discharging between the system and the power storage unit . The method of claim 1,
The voltage of the system is,
A power conversion device that is a voltage of a wire connecting the system and the conversion unit. delete The method of claim 1,
The operation unit generates a reference value based on the voltage value of the system received from the voltage measurement unit and stores the power conversion device in the storage unit. The method of claim 4,
The control unit further includes a communication unit that receives local weather information from an external network and transmits it to the operation unit,
The calculation unit,
Power conversion device for changing the reference value through the local weather information. delete delete delete delete delete

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