KR20150039039A - Power conditioning system and Energy storage system - Google Patents

Abstract

A power conversion apparatus according to an embodiment includes: a charge storing part which charges the voltage of a system; a conversion part which changes a voltage between the system and the charge storing part; and a control part which receives a first sensing voltage from the system, the charge storing part, and the conversion part, and controls the operation of the system, the charge storing part, and the conversion part according the first sensing voltage. The control part includes a sensing circuit which outputs a second sensing voltage which is changed by adjusting the magnification and level of the first sensing voltage.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a power conversion system and an energy storage system,

An embodiment relates to a power conversion apparatus.

An embodiment relates to an energy storage system.

A typical ESS (Energy Storage System) apparatus charges electricity when the demand of electric power is low on the system side. When the demand of electric power is high, electric power is supplied to the system by discharging the electric power of the power storage apparatus. At the same time, So as to stabilize the power.

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

The system, the conversion unit, and the power storage unit generate overvoltage during operation, damaging the internal circuit of the power conversion apparatus. Also, stable power conversion is required through switching according to the voltage change of the system, the converter, and the power storage unit.

Conventionally, the control unit detects the voltages of the system, the conversion unit, and the power storage unit and controls the switches of the system, the conversion unit, and the power storage unit to prevent damage to the internal circuit. However, the control unit operates only at an input voltage within a certain range, There is a problem in that the range of the input voltage of the control unit is different.

The embodiment provides a power conversion apparatus that can protect the control unit when there is a sudden change in the system voltage.

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

A power conversion apparatus according to an embodiment includes: a power storage unit for charging a voltage from a system; A converter for converting a voltage between the system and the power storage unit; And a controller receiving a first sensing voltage from the system, the power storage unit, and the conversion unit, and controlling operations of the system, the power storage unit, and the conversion unit according to the first sensing voltage, And a sensing circuit for outputting a second sensing voltage whose magnitude is adjusted and level-changed.

An energy storage system according to an embodiment includes: a system for supplying electric power; A load that consumes the power; And a power converter for storing power from the system or supplying stored power to the load, wherein the power converter comprises: a power storage unit for charging a voltage from the system; A converter for converting a voltage between the system and the power storage unit; And a controller receiving a first sensing voltage from the system, the power storage unit, and the conversion unit, and controlling operations of the system, the power storage unit, and the conversion unit according to the first sensing voltage, And a sensing circuit for outputting a second sensing voltage whose magnitude is adjusted and level-changed.

The power conversion apparatus according to the embodiment may include a protection unit for preventing damage to the internal circuit of the control unit so that the control unit can be protected even if the system voltage suddenly changes.

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

1 is a block diagram illustrating an energy storage system according to an embodiment.
2 is a block diagram showing a power conversion apparatus according to an embodiment.
3 is a circuit diagram showing a connection relationship between the power conversion apparatus and the system according to the embodiment.
4 is a block diagram showing a control unit according to an embodiment.
5 shows a sensing circuit according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between .

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. Also, the terms " part, ""module," and " module ", etc. in the specification mean a unit for processing at least one function or operation and may be implemented by hardware or software or a combination of hardware and software have.

Referring to FIG. 1, an energy storage system according to an embodiment may include a system 10, a load 20, a power inverter 30, and a switch 40.

The system (10) transfers power to the load (20) and the power inverter (30). The system 10 can supply the power required for the consumption of the load 20 and the power required for charging the power conversion device 30. [ The system 10 provides the power conversion device 30 with various information necessary for charging or discharging determination of the power conversion device 30 and information necessary for calculating the electricity rate, . ≪ / RTI > The system 10 may include various management servers for managing electricity usage and electricity charges. The system 10 may be a vehicle, a solar cell, a domestic power storage system, or the like.

The load 20 may receive power from the system 10 or the power conversion device 30 and consume the power. The load 20 is supplied with power from the system 10 when the switch 40 is short-circuited and can be supplied with electric power from the power conversion device 30 when the switch 40 is opened.

The power conversion device 30 receives electricity tariff information that changes in real time from the system 10 and purchases electricity from the system 10 and stores the electricity in a battery or stores the stored electricity into the system 10 can do. Further, the power converter 30 can supply the charged electricity to the load 20. [ The power conversion device 30 may receive information on the amount of charged electricity charged in the battery from an internal battery, thereby charging or discharging electricity to the battery.

The power conversion apparatus 30 is connected to the system 10 and the load 20 by a variety of communication methods including a wired or wireless communication method and a power line communication method, To each other.

The power conversion device 30 transmits charge information of the system 10 that is a basis for charge / discharge, charge amount or discharge amount measurement information for charge calculation, purchase and expenditure information to / from the system 10, .

In addition, the power converter 30 can set various charging and discharging criteria and criteria for purchase and sale based on the charging information of the system 10, which is a reference of the charging / discharging, .

In addition, the power conversion apparatus 30 transmits the amount of sales and purchase of the system 10 and the electric power (electricity) and the cost information to the system 10 through the user information recognition, charges the cost, The system 10 can transmit or receive information related to the billing function,

The charge / discharge control of the power converter 30 and the power transfer to the load 20 are determined by the power converter 30. However, the charge / discharge control and the charge / Power transmission judgment can be made. In this case, the power converter 30 may perform charge / discharge under the control of the controller.

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

The power inverter 30 may include a controller 100, a filter 110, a converter 120, a voltage-down converter 130, and a power storage 140.

The power conversion apparatus 30 stores the AC input power transmitted to the system 10 under the control of the controller 100 in the power storage unit 140 and controls the AC input power Power can be generated from the power storage unit 140 toward the system 10.

The control unit 100 may apply a control signal for controlling the filter unit 110, the conversion unit 120, the decompression unit 130, and the power unit 150 to each configuration. The control unit 100 may control charge / discharge between the system 10 and the power storage unit 140.

The control unit 100 may control the operations of the filter unit 110, the conversion unit 120, the decompression unit 130, and the power supply unit 150. The control unit 100 can control the operation of the power conversion device 30 by controlling the switches included in each configuration of the power conversion device 30. [

The controller 100 may sense the voltage of each configuration of the power converter 30 and stop the operation of the power converter 30 when an overvoltage is applied to each configuration of the power converter 30 have. The control unit 100 senses the voltage of the system 10, the voltage-decreasing unit 130 and the power supply unit 150 to determine that the voltage is an overvoltage when the voltage is equal to or higher than the reference voltage, So that the internal configuration of the power conversion device 30 can be protected. The power conversion device 30 may stop the operation of the power conversion device 30 by opening a switch included in the power conversion device 30 when it is determined that the overvoltage is generated. In addition, the controller 100 senses the voltage of each configuration of the power converter 30 and controls driving of the power converter 30, so that stable power conversion can be performed.

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

The converter 120 is a bidirectional converter that rectifies the input AC power when the power storage unit 140 is charged from the system 10 and smoothly transmits the smoothed power to the power storage unit 130, The DC voltage of the power storage unit 140 may be converted into an AC voltage and transmitted to the system 10 through the filter unit 110. [ In other words, the converting unit 120 can convert an AC voltage to a DC voltage, and convert a DC voltage to an AC voltage.

The boosting and depressurizing unit 130 may reduce the DC voltage supplied from the converting unit 120 to a level that the power storage unit 140 can store and deliver the reduced voltage to the power storage unit 140. The boost / depressurization unit 130 boosts the DC voltage supplied from the power storage unit 140 and transmits the boosted DC voltage to the conversion unit 120.

The power storage unit 140 may be a battery. The power storage unit 140 stores a DC voltage transmitted from the system 10 through the pressure reducing unit 130 and outputs the stored DC voltage according to a control signal from the controller 100 .

Referring to FIG. 3, the power conversion apparatus according to the embodiment may include a filter unit 110, a conversion unit 120, a step-up / down unit 130, and a power storage unit 140.

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

The control unit 110 may sense the 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 connect 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 is capable of generating noise and static electricity that may be generated when AC voltage is stored from the system 10 to the power storage unit 140, And filter static electricity that may be generated 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 the 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 between the first node N1 and the third node N3. And 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 between the second node N2 and the third node N3, And 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 and Q3 and the fourth node N4 is a node between the fourth inductor L4 and the fourth inductor L4, And 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 so that the DC voltages of the first and second nodes N1 and N2 are alternately Voltage to the third and fourth nodes N3 and N4 or to convert the AC voltage of the third to fourth nodes N3 to N4 into the DC voltage, N1, N2).

The first to fourth diodes D1 to D4 serve as protection elements for the first to fourth transistors Q1 to Q4 to prevent 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 voltage-up / down unit 130 and transmits the DC voltage to the first to fourth transistors Q1 to Q4. The first to fourth transistors Q1 to Q4 And smoothes the voltage input from the voltage-up / down unit 130 to the boost /

The control unit 100 may sense the voltage of the conversion unit 120. The controller 100 may sense a voltage across the connection capacitor Clink.

The voltage-down unit 130 includes two diodes Da and Db connected in parallel to two transistors Qa and Qb and a pair of the transistors Qa and Qb, And includes an inductor La and a capacitor Ca connected thereto. The voltage-decreasing unit 130 may reduce the voltage stored in the connection capacitor Clink of the transforming unit 120 and may transfer the voltage to the power storage unit 140. The voltage received from the power storage unit 140 may be And can be applied to the connection capacitor Clink of the conversion unit 120. The two transistors Qa and Qb of the boost / depressurization unit 130 may also be controlled by the control unit 100.

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

4, the control unit 100 according to the embodiment may include a sensing circuit 101, a signal processing unit 107, and a level shifter 109. FIG.

The control unit 100 receives the voltage shown in FIG. 3 and generates and outputs a control signal con. The controller 100 receives the voltage shown in FIG. 3 as the first sensing voltage Vs1, and generates and outputs the control signal con through the first sensing voltage Vs1.

The first sensing voltage (Vs1) may be a voltage of each configuration of the power converter (30). The first sensing voltage Vs1 may be a voltage of the system 10, the conversion unit 120, and the power storage unit 140. [ The first sensing voltage Vs1 may be the voltage shown in FIG.

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 magnitude of the magnified voltage to generate the second sensing voltage Vs2 ). 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 level-changed voltage after the first sensing voltage Vs1 is scaled. The second sensing voltage Vs2 is input to the signal processor 107.

The signal processing unit 107 may receive the second sensing voltage Vs2 and may calculate the second sensing voltage Vs2 to output a line control signal precon. The second sensing voltage Vs2 may be a voltage within a range that the signal processing unit 107 can process. The second sensing voltage Vs2 may be a voltage having a positive voltage value that the signal processing unit 107 can process. The second sensing voltage Vs2 may range from 0V to 3V.

The sensing circuit 101 changes the first sensing voltage V1 to a second sensing voltage V2 that can be processed by the signal processing unit 107 so that the signal processing unit 107 controls the power conversion unit 30, It is possible to recognize the voltage of each configuration and to stably drive the voltage.

The line control signal precon may be a signal for outputting a voltage and a current of a predetermined level by controlling each configuration of the power conversion device 30. [ The line control signal precon may be a pulse width modulation (PWM) signal.

The level shifter 109 receives the line control signal precon and outputs a control signal con. The level shifter 109 may amplify the line control signal precon and output it as a control signal con.

The control signal con may serve to stabilize the output of the power conversion device 30. [ The control signal con controls on / off of the transistors of the power converter 30 to control the voltage of each configuration of the power converter 30 to a constant level. The control signal con may control the conversion unit 120 and the step-up / down unit 130. The control signal con controls on-off of the first to fourth transistors Q1 to Q4 of the conversion unit 120 and the two transistors Qa and Qb of the voltage-down unit 130, The voltage of each configuration of the converting apparatus 30 can be controlled at a constant level. The control signal con may be a PWM signal.

5, the sensing circuit 101 according to the embodiment may include a protection unit 102, an amplification unit 103, and a modification 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.

The first sensing voltage Vs1 is input to the noninverting input terminal of the first operational amplifier Amp1 and the inverting input terminal and the 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 conversion device 30 so that there is no influence on the sensing circuit 101 even if the change in the first sensing voltage Vs1 is large. That is, the protection unit 102 can prevent the sensing circuit 101 from being damaged by the variation of the first sensing voltage Vs1. The protection unit 102 may prevent damage to the signal processing unit 107 and the level shifter 109 connected to the sensing circuit 101 as well as the sensing circuit 101. The protection unit 102 can prevent the internal circuit of the controller 100 from being damaged. The protection unit 102 protects the sensing circuit 101 and does not change the voltage so that the first voltage V1 may be the first sensing voltage Vs1.

The amplification unit 103 may include a second operational amplifier Amp2. The amplifier 103 receives the first voltage V1 and the first reference voltage Vref, scales it, and outputs the second voltage V2. In other words, the amplifier 103 may scale the magnitude of the first voltage V1 and output it as the second voltage V2.

The first reference voltage Vref may be input to the noninverting 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 part 102 and the amplification part 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 output the second voltage V2 by scaling the magnitude of the first voltage V1.

The changing unit 104 may include a third operational amplifier Amp3. The changing unit 104 receives the second voltage V2 and the second reference voltage Vref2 and changes the level of the second voltage V2 to output the second sensing voltage Vs2.

A second voltage V2 is applied to the inverting input terminal of the third operational amplifier 104 and a second reference voltage Vref2 is applied to the noninverting input terminal of the third operational amplifier 104, The output terminal of the amplifier 104 may output the second sensing voltage Vs2.

In the embodiment, the sensing circuit 101 scales the level of the first sensing voltage Vs1 from the power conversion device 30, changes the level, and transfers the level to the signal processing unit 107, Can be transmitted to the second sensing voltage (Vs2) without distortion of the sensing voltage (Vs1), thereby preventing signal distortion and enabling stable operation of the power conversion device (30).

The sensing circuit 101 according to the embodiment is formed of an analog circuit, not a digital circuit, and is advantageous in that signal processing is easy in external noise, processing speed, bandwidth limitation, and the like. In addition, when the control unit 100 is interlocked with a phase lock loop, the variation of the output frequency can be reduced.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

10: System
20: Load
30: Power converter
40: Switch
100:
101: sensing circuit
102:
103: Amplification unit
104:
107: Signal processor
109: Level shifter
110:
120:
130:
140:

Claims (10)

A power storage unit for charging a voltage from the system;
A converter for converting a voltage between the system and the power storage unit; And
And a control unit for receiving a first sensing voltage from the system, the power storage unit, and the conversion unit, and controlling operations of the system, the power storage unit, and the conversion unit according to the first sensing voltage,
Wherein the control unit includes a sensing circuit for outputting a second sensing voltage obtained by scaling and level-changing the magnitude of the first sensing voltage. The method according to claim 1,
The control unit may further include a signal processing unit receiving the second sensing voltage and generating a control signal,
And the second sensing voltage is within a range that can be processed by the signal processing unit. The method according to claim 1,
The sensing circuit includes:
A protection unit for preventing damage to an internal circuit of the control unit;
An amplifying unit for scaling the magnitude of the first sensing voltage; And
And a changing unit for changing a level of the scaled voltage. The method of claim 3,
Wherein the sensing circuit is an analog circuit. 3. The method of claim 2,
Wherein,
And a level shifter for amplifying a control signal from the signal processing unit and supplying the amplified control signal to the system, the power storage unit, and the conversion unit. A power supply system;
A load that consumes the power;
And a power conversion device that stores power from the system or supplies stored power to the load,
The power conversion apparatus includes:
A power storage unit for charging a voltage from the system;
A converter for converting a voltage between the system and the power storage unit; And
And a control unit for receiving a first sensing voltage from the system, the power storage unit, and the conversion unit, and controlling operations of the system, the power storage unit, and the conversion unit according to the first sensing voltage,
Wherein the control unit includes a sensing circuit for outputting a second sensing voltage obtained by scaling and level-changing the magnitude of the first sensing voltage. The method according to claim 6,
The control unit may further include a signal processing unit receiving the second sensing voltage and generating a control signal,
And the second sensing voltage is a voltage within a range that the signal processing unit can process. The method according to claim 6,
The sensing circuit includes:
A protection unit for preventing damage to an internal circuit of the control unit;
An amplifying unit for scaling the magnitude of the first sensing voltage; And
And a changing unit for changing a level of the scaled voltage. 9. The method of claim 8,
Wherein the sensing circuit is an analog circuit. 8. The method of claim 7,
Wherein,
And a level shifter for amplifying the control signal from the signal processing unit and supplying the amplified control signal to the system, the power storage unit, and the conversion unit.

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