KR102063741B1 - Power conditioning system and Energy storage system - Google Patents

Abstract

Power conversion apparatus according to the embodiment, the power storage unit for charging the voltage from the grid; A conversion unit for converting a voltage between the grid and the power storage unit; And a controller configured to receive a first sensing voltage from the grid, the power storage unit, and the conversion unit, and to control an operation of the grid, power storage unit, and the conversion unit according to the first sensing voltage, wherein the controller is configured to control the first sensing voltage. And a sensing circuit for outputting a second sensing voltage obtained by scaling and level changing the size of the circuit.

Description

Power conversion system and energy storage system

Embodiments relate to a power converter.

Embodiments relate to an energy storage system.

A typical ESS (Energy Storage System) device charges when the demand for power is low on the grid side, and discharges power from the storage unit when the demand for power is high, and simultaneously supplies reactive power to the grid. It has a role of stabilizing power by instantaneous correction.

A power conditioning system (PCS) included in such an ESS device includes a converter that receives grid-side power, converts the power into DC power, converts the received DC power into AC power, and transfers the power to the grid and the load. A power storage unit for supplying a DC power supply to the conversion unit, and a control unit for controlling switches of the system, the conversion unit, and the power storage unit.

The system, the converting unit and the power storage unit may have an overvoltage in an operation process, thereby causing damage to an internal circuit of the power converter. In addition, stable power conversion is required through switching according to the voltage change of the system, the converter, and the power storage unit.

Conventionally, the controller detects the voltage of the grid, the converter, and the power storage unit to control the switches of the grid, the converter, and the power storage unit to prevent damage to the internal circuit. However, the controller operates only at an input voltage within a predetermined range. There was a problem that the range of the input voltage and the input voltage of the controller is different.

The embodiment provides a power converter that can protect the controller when there is a sudden change in the grid voltage.

The embodiment provides an energy storage system capable of stable power conversion without distorting the sensing voltage.

Power conversion apparatus according to the embodiment, the power storage unit for charging the voltage from the grid; A conversion unit for converting a voltage between the grid and the power storage unit; And a controller configured to receive a first sensing voltage from the grid, the power storage unit, and the conversion unit, and to control an operation of the grid, power storage unit, and the conversion unit according to the first sensing voltage, wherein the controller is configured to control the first sensing voltage. And a sensing circuit for outputting a second sensing voltage obtained by scaling and level changing the size of the circuit.

Energy storage system according to an embodiment, the system for supplying power; A load consuming the power; A power converter configured to store power from the system or to supply stored power to the load, wherein the power converter includes: a power storage unit configured to charge a voltage from the system; A conversion unit for converting a voltage between the grid and the power storage unit; And a controller configured to receive a first sensing voltage from the grid, the power storage unit, and the conversion unit, and to control an operation of the grid, the power storage unit, and the conversion unit according to the first sensing voltage. And a sensing circuit for outputting a second sensing voltage obtained by scaling and level changing the size of the circuit.

The power converter according to the embodiment may include a protection unit for preventing damage to the internal circuit of the control unit to protect the control unit even if there is a sudden change in the system voltage.

The energy storage system according to the embodiment may scale the magnitude of the sensing voltage using an analog circuit, and perform stable power conversion without distorting the sensing voltage by changing the voltage level.

1 is a block diagram illustrating an energy storage system according to an exemplary embodiment.
2 is a block diagram illustrating a power conversion apparatus according to an embodiment.
3 is a circuit diagram illustrating a connection relationship between a power converter and a grid according to an embodiment.
4 is a block diagram illustrating a controller according to an exemplary embodiment.
5 is a diagram illustrating a sensing circuit according to an exemplary embodiment.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. .

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may 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 embodiment may include a system 10, a load 20, a power converter 30, and a switch 40.

The system 10 transfers power to the load 20 and the power converter 30. The system 10 may supply power for consumption of the load 20, and may transfer power for charging the power converter 30. In addition, the system 10 is a system that provides various information necessary for determining the charge or discharge of the power converter 30 and information necessary for calculating the electric charge to the power converter 30 as a system such as a power exchange. It may include. The system 10 may include various management servers that manage electricity usage and electricity bills. The system 10 may be a vehicle, a solar cell, or a home power storage system.

The load 20 may receive power from the system 10 or the power converter 30 and consume it. The load 20 may receive power from the system 10 when the switch 40 is shorted, and may receive power from the power converter 30 when the switch 40 is opened.

The power converter 30 receives electricity rate information that changes in real time from the system 10 to purchase electricity from the system 10 and store the electricity in the storage battery, or sell the stored electricity to the system 10. can do. In addition, the power converter 30 may supply the charged electricity to the load 20. The power converter 30 may receive charge information of electricity charged in the storage battery from an internal storage battery, and charge or discharge electricity in the storage battery.

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

The power converter 30 transmits charge information of the system 10 as a reference for charging / discharging, charge or discharge amount measurement information for calculating a charge, and purchase and expenditure information with the system 10, or Can be received.

In addition, the power converter 30 may set various charging and discharging criteria and purchasing and selling criteria through the charge information on the basis of the charge information of the system 10 serving as a charging / discharging standard. Can be controlled by

In addition, the power conversion device 30 transmits the amount and cost information for selling and purchasing the system 10 and power (electricity) to the system 10 through user information recognition, charging the cost, and automatically selling the sales amount. The billing function related information to enable the settlement can be transmitted or received with the system 10.

In the above embodiment, the charging and discharging control of the power converter 30 and the power transfer to the load 20 is determined by the power converter 30, but the charge and discharge control and using a separate control unit Power delivery judgment can be made. In this case, the power converter 30 may perform charging and discharging under the control of the controller.

Referring to FIG. 2, the power converter 30 according to the embodiment may be connected to a grid.

The power converter 30 may include a control unit 100, a filter unit 110, a conversion unit 120, a boosting and lowering unit 130, and a power storage unit 140.

The power converter 30 stores the AC input power delivered to the grid 10 under the control of the control unit 100 in the power storage unit 140, for example, the AC input power is cut off if necessary. In this case, power may be generated from the power storage unit 140 toward the system 10.

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

The controller 100 may control operations of the filter unit 110, the converter 120, the booster 130, and the power supply 150. The controller 100 may control an operation of the power converter 30 by controlling a switch included in each component of the power converter 30.

The control unit 100 senses a voltage of each component of the power converter 30 to stop the operation of the power converter 30 when an overvoltage is applied to each component of the power converter 30. have. The controller 100 senses the voltages of the system 10, the booster 130, and the power supply 150 to determine an overvoltage when the voltage is greater than or equal to the reference voltage, thereby operating the power converter 30. The internal structure of the power converter 30 may be protected by stopping. When the power converter 30 is determined to be the overvoltage, the power converter 30 may stop the operation of the power converter 30 by opening a switch included in the power converter 30. In addition, the controller 100 senses the voltage of each component of the power converter 30, and controls the driving of the power converter 30, thereby enabling stable power conversion.

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

The converter 120 is a bidirectional converter, and when the power storage unit 140 is charged from the system 10, rectifies an input AC power supply and smoothes the power to the booster 130. When the power generation unit 140 generates power, the DC voltage of the power storage unit 140 may be converted into alternating current and transmitted to the system 10 through the filter unit 110. In other words, the converter 120 may convert an AC voltage into a DC voltage and convert the DC voltage into an AC voltage.

The booster 130 may reduce the DC voltage supplied from the converter 120 to a level that can be stored by the power storage unit 140, and transmit the reduced voltage to the power storage unit 140. The booster 130 may boost the DC voltage supplied from the power storage unit 140 and transfer the boosted voltage to the converter 120.

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

Referring to FIG. 3, the power converter according to the embodiment may include a filter unit 110, a converter unit 120, a booster unit 130, and a power storage unit 140.

The system 10 may be electrically connected to the filter unit 110.

The controller 110 may sense voltages at both ends of the system 10.

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 be connected between the first inductor L1 and the third inductor L3 and between the second inductor L2 and the fourth inductor L4.

The filter unit 110 including the first to fourth inductors L1 to L4 and the capacitor C may generate noise and static electricity when the AC voltage is stored from the grid 10 to the power storage unit 140. The filter may filter static electricity generated when a voltage is output from the power storage unit 140 to the system 10.

The converter 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 controller 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 connected to each other. 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 connected to each other. It may be connected between the second node N1 and the fourth node N4.

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

The first and fourth transistors Q1 and Q4 operate simultaneously, and the second and third transistors Q2 and Q3 operate simultaneously, thereby alternating DC voltages of the first and second nodes N1 and N2. Converts the voltage to the third and fourth nodes N3 and N4, and transfers the AC voltages of the third to fourth nodes N3 to N4 to the DC voltages to convert the voltage into the DC voltage. 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 a 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 booster 130 and transfers the DC voltage 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 booster 130.

The controller 100 may sense the voltage of the converter 120. The controller 100 may sense a voltage across the connection capacitor Clink.

The booster 130 includes two transistors Qa and Qb, two diodes Da and Db connected in parallel with the transistors Qa and Qb, and two transistors Qa and Qb, respectively. It includes an inductor (La) and a capacitor (Ca) to be connected. The booster 130 may reduce the voltage stored in the connection capacitor Clink of the converter 120, transfer the reduced voltage to the power storage 140, and receive the voltage received from the power storage 140. The voltage may be increased and applied to the connection capacitor Clink of the converter 120. Two transistors Qa and Qb of the booster 130 may also be controlled by the controller 100.

The controller 100 may sense a voltage across the power storage unit 140.

Referring to FIG. 4, the controller 100 according to the embodiment may include a sensing circuit 101, a signal processor 107, and a level shifter 109.

The controller 100 receives the voltage shown in FIG. 3 and generates and outputs a control signal con. The controller 100 may receive the voltage shown in FIG. 3 as the first sensing voltage Vs1, and generate and output a control signal con.

The first sensing voltage Vs1 may be a voltage of each component of the power converter 30. The first sensing voltage Vs1 may be a voltage of the system 10, the converter 120, and the power storage unit 140. The first sensing voltage Vs1 may be the voltage shown in FIG. 3.

The sensing circuit 101 receives the first sensing voltage Vs1 and outputs a second sensing voltage Vs2. The sensing circuit 101 receives the first sensing voltage Vs1, scales the magnitude of the first sensing voltage Vs1, and changes the level of the scaled voltage to change the second sensing voltage Vs2. Can be printed as That is, the sensing circuit 101 receives the first sensing voltage Vs1, and scales and level shifts the first sensing voltage Vs1 to output the second sensing voltage Vs2.

The second sensing voltage Vs2 may be a voltage level changed after scaling the first sensing voltage Vs1. The second sensing voltage Vs2 is input to the signal processor 107.

The signal processor 107 may receive the second sensing voltage Vs2, calculate the second sensing voltage Vs2, and output a line control signal precon. The second sensing voltage Vs2 may be a voltage within a range that can be processed by the signal processor 107. The second sensing voltage Vs2 may be a voltage having a positive voltage value that can be processed by the signal processor 107. The second sensing voltage Vs2 may be 0V to 3V.

The sensing circuit 101 changes the first sensing voltage V1 into a second sensing voltage V2 that can be processed by the signal processor 107 so that the signal processor 107 converts the power to the power converter 30. By recognizing the voltage of each component of the can be made to be driven stably.

The pre-control signal precon may be a signal for controlling each component of the power converter 30 and outputting a predetermined level of voltage and current. The line control signal precon may be a pulse width modulation (PWM) signal.

The level shifter 109 may receive the line control signal precon and output a control signal con. The level shifter 109 may amplify the pre-control signal precon and output it as a control signal con.

The control signal con may serve to stabilize the output of the power converter 30. The control signal con controls the on / off of the transistor of the power converter 30 to control the voltage of each component of the power converter 30 to a predetermined level. The control signal con may control the converter 120 and the booster 130. The control signal con controls the on / off of the first to fourth transistors Q1 to Q4 of the converter 120 and the two transistors Qa and Qb of the booster 130. The voltage of each component of the converter 30 can be controlled at a constant level. The control signal con may be a PWM signal.

Referring to FIG. 5, the sensing circuit 101 according to the embodiment may include a protection unit 102, an amplifier 103, and a change unit 104.

The protection unit 101 may include a first operational amplifier Amp1. The protection unit 101 may receive the first sensing voltage Vs1 and output the first voltage V1.

A first sensing voltage Vs1 is input to a non-inverting input terminal of the first operational amplifier Amp1, and an inverting input terminal and an output terminal of the first operational amplifier Amp1 may be connected. The voltage output to the output terminal of the first operational amplifier Amp1 may be the first voltage V1.

The input impedance of the first operational amplifier Amp1 is greater than the impedance of the power converter 30 so that the sensing circuit 101 is not affected even if the first sensing voltage Vs1 is large. That is, the protection unit 102 may prevent damage of the sensing circuit 101 due to the change of the first sensing voltage Vs1. In addition, the protection unit 102 may prevent damage not only to the sensing circuit 101 but also to the signal processor 107 and the level shifter 109 connected to the sensing circuit 101. The protection unit 102 may prevent damage to the internal circuit of the control unit 100. Since the protection unit 102 protects the sensing circuit 101 and does not change the voltage, the first voltage V1 may be the first sensing voltage Vs1.

The amplifier 103 may include a second operational amplifier Amp2. The amplifier 103 may receive a first voltage V1 and a first reference voltage Vref and scale it and output the same as the second voltage V2. In other words, the amplifier 103 may scale the magnitude of the first voltage V1 to output the second voltage V2.

The first reference voltage Vref may be input to the non-inverting input terminal of the second operational amplifier Amp2, and the first voltage V1 may be applied to the inverting input terminal of the second operational amplifier Amp2. The inverting input terminal and the output terminal of the second operational amplifier Amp2 may be connected.

Although not shown, a resistor may be connected between the insulation unit 102 and the amplifier 103, and a resistor may be connected between the inverting input terminal and the output terminal of the second operational amplifier Amp2.

The second operational amplifier Amp2 may scale the magnitude of the first voltage V1 to output the second voltage V2.

The changer 104 may include a third operational amplifier Amp3. The changer 104 may receive the second voltage V2 and the second reference voltage Vref2, change the level of the second voltage V2, and output the second voltage V2 as the second sensing voltage Vs2.

The second voltage V2 is applied to the inverting input terminal of the third operational amplifier 104, the second reference voltage Vref2 is applied to the non-inverting input terminal of the third operational amplifier 104, and the third operation is performed. The output terminal of the amplifier 104 may output the second sensing voltage Vs2.

In an embodiment, the sensing circuit 101 scales the magnitude of the first sensing voltage Vs1 from the power converter 30, changes the level, and transfers the level to the signal processor 107. The second sensing voltage Vs2 may be transmitted without distortion of the sensing voltage Vs1, thereby preventing distortion of the signal, and thus, the stable power converter 30 may be operated.

The sensing circuit 101 according to the embodiment is formed of an analog circuit, not a digital circuit, and thus has an advantage of easy signal processing in external noise, processing speed, and bandwidth limitation. In addition, when the control unit 100 is interlocked with a phase lock loop, there is an advantage of reducing the variation of the output frequency.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. In addition, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be interpreted that the contents related to such a combination and modification are included in the scope of the present invention.

In addition, the above description has been made with reference to the embodiments, which are merely illustrative and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains are described above within the scope not departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

10: system
20: load
30: power inverter
40: switch
100: control unit
101: sensing circuit
102: protection
103: amplifier
104: change part
107: signal processing unit
109: level shifter
110: filter unit
120: converter
130: pressure reducing unit
140: power storage

Claims (10)

A power storage unit for charging electric power transmitted from the system;
A conversion unit disposed between the grid and the power storage unit to convert the power of the grid into power that can be charged in the power storage unit, and convert discharge power from the power storage unit into power that can be supplied to the grid; And
A control unit configured to receive a first sensing voltage from the system, the power storage unit, and the conversion unit, and control an operation of the system, the power storage unit, and the conversion unit according to the first sensing voltage,
The control unit,
A sensing circuit insulated from the converter and outputting a second sensing voltage in which the magnitude of the first sensing voltage is changed;
A signal processor configured to receive the second sensing voltage and generate a control signal,
The sensing circuit,
A protection unit insulated from the power converter, receiving the first sensing voltage, outputting a first voltage, and including a first operational amplifier;
An amplifier configured to receive the first voltage, scale the magnitude of the first voltage, output the second voltage, and include a second operational amplifier; And
Receiving the second voltage, changing the level of the second voltage to output the second sensing voltage, and including a third operational amplifier,
The magnitude of the first voltage is,
The power conversion device equal to the magnitude of the first sensing voltage. The method of claim 1,
Input impedance of the first operational amplifier constituting the protection unit,
Power conversion device larger than the impedance of the conversion unit. The method of claim 2,
And the sensing circuit is an analog circuit. The method of claim 1,
The control unit,
And a level shifter to amplify a control signal from the signal processor and to supply the system, the power storage unit, and the conversion unit, respectively. delete delete delete delete delete delete

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