KR102052950B1 - Power conditioning system and Method of driving the same - 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 power supply unit supplying a power supply voltage to the conversion unit and the power storage unit, wherein the power supply unit comprises: a first transformer receiving a voltage from the system and supplying a power voltage to the conversion unit and the power storage unit; And a second transformer receiving a voltage from the power storage unit and applying a voltage to the first transformer.

Description

Power conditioning system and method of driving the same

Embodiments relate to a power converter.

The embodiment relates to a method of driving a power converter.

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.

Such an ESS device includes a converter which receives grid-side power and converts the power into DC power, converts the received DC power into AC power, and transfers the power to the grid and the load, and a power storage unit that supplies the DC power of the battery to the converter. And a booster for boosting or stepping down a DC voltage between the converter and the power storage unit, a controller for controlling the operation of each of the components, and a power supply unit for supplying a driving voltage to each of the components.

The power supply unit of the conventional ESS device receives a voltage from the output terminal of the converter, divides it, and supplies a driving voltage to each of the components. At this time, since the voltage received from the output terminal of the conversion unit is a high voltage, the elements constituting the power supply unit must be configured with a high capacity, there is a problem of manufacturing cost increase.

The embodiment provides a power conversion apparatus that can reduce the capacity of the power supply internal configuration.

The embodiment provides a method of driving a power converter that can supply a stable power supply 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 power supply unit supplying a power supply voltage to the conversion unit and the power storage unit, wherein the power supply unit comprises: a first transformer receiving a voltage from the system and supplying a power voltage to the conversion unit and the power storage unit; And a second transformer receiving a voltage from the power storage unit and applying a voltage to the first transformer.

In one embodiment, a method of driving a power converter includes applying a system output voltage from a system to a first transformer; Generating, by the first transformer, a power supply voltage using the grid output voltage; Applying the power supply voltage to a converter and a power storage unit; Applying a power storage output voltage of the power storage unit to a second transformer; Dividing the electrical storage output voltage by the second transformer and applying the voltage to the first transformer; And generating a supply voltage by dividing the voltage from the second transformer by the first transformer.

The power supply unit of the power converter according to the embodiment uses two transformers, and can be directly applied to the voltage from the system to lower the voltage level applied to the power supply unit can reduce the capacity of the internal configuration of the power supply unit to reduce the manufacturing cost effect have.

In the driving method of the power converter according to the embodiment, the initial power supply voltage is supplied by receiving a voltage from the system, and even after the system and the power conversion device are separated, the power supply can be supplied by supplying the power supply voltage to the stable power supply voltage. Supply is possible.

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 power converter according to an embodiment.
4 is a flowchart illustrating a method of driving a power converter according to an 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.

1 is a block diagram illustrating an energy storage system according to an exemplary embodiment.

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.

2 is a block diagram illustrating a power conversion apparatus according to an embodiment.

Referring to FIG. 2, the power converter 30 according to the embodiment may be connected to the system 10.

The power converter 30 may include a control unit 100, a filter unit 110, a conversion unit 120, a boosting and lowering unit 130, a power storage unit 140, and a power supply unit 150.

The power converter 30 stores the AC input power transmitted from 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 control unit 100 may apply a control signal for controlling the filter unit 110, the converter unit 120, the boosting and lowering unit 130, the power storage unit 140, and the power supply unit 150 to each component. The controller 100 may control charging and discharging between the system 10 and the power storage unit 140.

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. .

The power supply unit 150 may apply a power supply voltage to each component of the power converter 30. The power supply unit 150 receives an AC voltage from the system 10, receives a DC voltage from the power storage unit 140, divides the AC voltage and the DC voltage, and generates a power voltage to generate the power conversion device ( 30) can be applied in each configuration.

Since the power converter 30 requires different power supply voltages according to the configuration, the power supply unit 150 may generate a power supply voltage by dividing the AC voltage and the DC voltage to a plurality of different levels.

The power supply unit 150 may apply a power supply voltage to each component of the energy storage system as well as each component of the power converter 30.

The power supply unit 150 may include a first transformer 151 and a second transformer 153.

The first transformer 151 may have a structure symmetrical with the second transformer 153.

The first transformer 151 receives the AC voltage from the system 10, rectifies and divides the voltage, generates power voltages having a plurality of different levels, and applies them to the respective components of the power converter 30. can do.

The second transformer 153 may receive a DC voltage from the power storage unit 140, divide the voltage, and transfer the DC voltage to the first transformer 151.

In other words, the first transformer 151 receives the AC voltage from the system 10, generates a power supply voltage, applies the power voltage to the power converter 30, and the power converter 30 supplies the power. It is operated by the voltage to charge the power storage unit 140. Thereafter, the power storage unit 140 transmits a DC voltage to the second transformer 153, and the second transformer 153 divides the voltage to the first transformer 151 and divides the voltage into the first transformer 151. Generates a power supply voltage having two levels.

The first transformer 151 may initially generate an AC voltage from the system 10 to generate a power supply voltage required for initial operation of each component of the power converter 30. Since the first transformer 151 receives a DC voltage from the second transformer 153 afterwards, the power storage unit 140 may be disconnected even when the system 10 is disconnected from the power converter 30. ) Can be used to generate a power supply voltage stably.

In addition, the second transformer 153 receives a DC voltage from the power storage unit 140 instead of the output terminal of the conversion unit 120 to provide a DC voltage having a relatively lower level than the output terminal of the conversion unit 120. Can be authorized. In addition, an AC voltage having an effective value lower than an output terminal of the converter 120 is applied to the first transformer 151. Since the first transformer 151 and the second transformer 153 receive a voltage having a relatively low level compared to the prior art, the internal components having the small capacity of the first transformer 151 and the second transformer 153 It can be configured as. As a result, the manufacturing cost of the power converter 30 including the power supply unit 150 may be reduced. In addition, since the first transformer 151 and the second transformer 153 receive a voltage having a relatively low level compared to the prior art, the distance between the wirings to consider the electric field effect can be reduced, and as a result, the power supply unit 150 is formed. The size of the printed circuit board can be reduced, thereby reducing the size of the power converter 30.

In another embodiment, the second transformer 153 may generate a power supply voltage having a plurality of levels different from the DC voltage received from the power storage unit 140 and apply the generated power voltage to each component of the power converter 30. have. In this case, the first transformer 151 generates and supplies an initial power supply voltage of the power converter 30, and then generates a power supply voltage through the second transformer 153 to generate the power supply device 30. ) Can also be used.

The first transformer 151 and the second transformer 153 may be a boost converter, a buck converter, a buck-boost converter, a fly-back converter, or It may be an LCC converter.

3 is a circuit diagram illustrating a power converter according to an embodiment.

Referring to FIG. 3, the system 10 is connected to the power converter 30 according to the embodiment.

The system 10 may output the three-phase AC voltage to the power converter 30.

The system 10 may output three phase AC voltages through three wires. The three wires may be an R line, an S line, and a T line. The R, S and T lines may be defined in any order.

Three-phase AC voltage from the system 10 may be input to the filter unit 110 through the R line, S line and T line. Although not shown, three wires connecting the system 10 and the filter unit 110 will be described by defining R lines, S lines, and T lines in order from top to bottom.

The filter unit 110 may include first to sixth inductors L1 to L6 connected to each of three wires in series.

The first inductor L1 and the fourth inductor L4 are connected in series to the R line, and the second inductor L2 and the fifth inductor L5 are connected in series to the S line. The third inductor L3 and the sixth inductor L6 may be connected in series to the T line.

First to third capacitors C1 to C3 may be connected between the R line, the S line, and the T line. The first capacitor C1 may be connected between the R line and the S line, the second capacitor C2 may be connected between the S line and the T line, and the third capacitor C3 may be connected to the R line. It may be connected between the T line.

The filter unit 110 including the first to sixth inductors L1 to L6 and the first to third capacitors C1 to C3 receives an AC voltage from the grid 10 to the power storage unit 140. Noise and static electricity that may be generated during storage may be filtered, and static electricity that may be generated when a voltage is output from the power storage unit 140 to the grid 10 may be filtered.

The converter 120 may include first to sixth transistors Q1 to Q6, first to sixth diodes D1 to D6, and a connection capacitor Clink.

The first to sixth transistors Q1 to Q6 and the first to sixth diodes D1 to D6 may form a bridge between the first and second nodes N1 and N2.

The first to sixth transistors Q1 to Q6 may be controlled by first to sixth signals S1 to S6, respectively. The first to sixth transistors Q1 to Q6 may be connected in parallel with the first to sixth diodes D1 to D6, respectively. The first to sixth 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. The third node Q3 and the third diode D3 are connected between the first node N1 and the fourth node N4, and the third node Q3 and the third diode D3 are connected between the first node N1 and the fifth node N5. Can be.

The fourth transistor Q4 and the fourth diode D4 are connected between the second node N2 and the third node N3, and the fifth transistor Q5 and the fifth diode D5 are connected to the fourth node Q4 and the fourth diode D4. The sixth transistor Q6 and the sixth diode D6 may be connected between the second node N1 and the fourth node N4, and may be connected between the second node N1 and the fifth node N5. Can be.

The third node N3 is a contact with the R line to which the fourth inductor L4 is connected, and the fourth node N4 is a contact with the S line to which the fifth inductor L5 is connected, and the fifth The node N5 may be a contact with the T line to which the sixth inductor L6 is connected.

The first to sixth transistors Q1 to Q6 are paired on and off to convert DC voltages of the first and second nodes N1 and N2 into AC voltages, thereby converting the third to fifth nodes N3 to N5. ), Or converts the AC voltage of the third to fifth nodes N3 to N5 into the DC voltage and transfers the DC voltage to the first and second nodes N1 and N2.

The first to sixth diodes D1 to D6 are protection elements of the first to sixth transistors Q1 to Q6 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 sixth transistors Q1 to Q6, or the first to sixth transistors Q1 to Q6. The voltage input from) may be smoothed and transferred to the booster 130.

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.

The power supply unit 150 may include a first transformer 151 and a second transformer 153. The first transformer 151 and the second transformer 153 may be a flyback converter. Since the first transformer 151 and the second transformer 153 are formed to be symmetrical with each other, the description of the second transformer 153 is replaced with the description of the first transformer.

The first transformer 153 is composed of a coil having a turns ratio of n1: n2. The first transformer 153 includes a primary coil, that is, a primary circuit connected to the input side coil and a secondary coil, that is, a secondary circuit connected to the output side coil. The primary circuit and the secondary circuit may be insulated by a coil.

The primary circuit of the first transformer 153 receives an AC voltage from the system 10. The first transformer 153 may receive the voltage of any one of the three-phase AC voltage of the system 10. In the drawing, the first transformer 153 may receive a voltage from the S line.

The primary circuit includes a snubber. The snubber may include a resistor Rsn, a capacitor Csn, and a diode Dsn. The snubber may serve to protect the internal configuration of the first transformer 151 by preventing a sudden rise of the input current and voltage. The first transformer may transmit the voltage input from the S line to the primary coil direction through the snubber.

A transistor may be formed between the primary coil and the ground terminal of the primary circuit. The transistor may serve to control an energy charging or transferring operation of the first transformer 153 by switching an input voltage in response to a control signal from the controller 100. The transistor may be controlled by an output voltage fed back from the secondary circuit.

The secondary circuit may be composed of a plurality of coils having different turns ratios. Although the secondary circuit in the drawing shows a circuit having a coil having a turns ratio of n 2 and a turns ratio of n 3, it may be configured as a circuit having two or more coils. The secondary circuit may divide and output an input voltage applied to the primary circuit according to respective turns ratios to voltages having different levels.

A plurality of voltages output from the secondary circuit of the first transformer 151 may be used as the power supply voltage of the power converter 30.

The second transformer 152 may receive a voltage from the power storage unit 140. A connection diode Dlink may be formed between the power storage unit 140 and the second transformer 152. The connection diode Dlink may prevent the voltage of the second transformer 152 from being applied to the power storage unit 140.

The primary circuit of the second transformer 152 may receive the voltage of the power storage unit 140, divide the voltage and output the secondary output voltage to the secondary circuit.

The primary circuit of the first transformer 151 and the second transformer 152 may be electrically connected. The secondary output voltage may be transferred to the primary circuit of the first transformer 151 and used to generate a power supply voltage. In other words, the second transformer 152 divides the voltage from the power storage unit 140 and outputs the secondary output voltage, and the primary circuit of the first transformer 151 divides the secondary output voltage. A plurality of power supply voltages can be generated and applied to each component of the power converter.

4 is a flowchart illustrating a method of driving a power converter according to an embodiment.

Referring to FIG. 4, in the driving method of the power converter according to the embodiment, the voltage output from the system 10 is applied to the first transformer 151. (S101)

The voltage output from the system 10 is only applied to the first transformer 151, and no power voltage is applied to the power converter 30, so that the power converter 30 is not operated. .

The first transformer 151 divides the voltage from the system 10 to generate a power supply voltage having a plurality of different levels (S102).

The secondary side of the first transformer 151 applies the power supply voltage to each component of the power converter 30 (S103).

The power converter 30 is operated by receiving the power supply voltage. The first transformer 151 may generate a voltage required for initial operation of each component of the power converter 30 by receiving an AC voltage from the system 10.

The voltage from the system 10 is applied to the power storage unit 140 through the filter unit 110, the converter 120, and the booster unit 130 to charge the power storage unit 140. (S104)

The voltage of the power storage unit 140 is transmitted to the primary circuit of the second transformer 153. The first transformer 153 divides the voltage delivered to the primary circuit and outputs the secondary output voltage to the secondary circuit (S105).

The second transformer 153 receives a DC voltage from a level lower than that of the converter 120 by receiving a DC voltage from the power storage unit 140 instead of the output terminal of the converter 120. Can be. Since the second transformer 153 receives a voltage of a relatively low level in the prior art, the second transformer 153 may be configured with internal components having a small capacity. As a result, the manufacturing cost of the power converter 30 including the power supply unit 150 may be reduced, and the size of the printed circuit board on which the power supply unit 150 is formed may be reduced.

The second transformer 153 applies the secondary output voltage to the primary side of the first transformer 151. The first transformer 151 divides the secondary output voltage to generate a power supply voltage (S106).

The first transformer 151 may receive the voltage of the power storage unit 140 through the second transformer 153, even if the system 10 is disconnected from the power converter 30. By using the power charged in the power storage unit 140, it is possible to stably generate a power supply voltage.

10: system
20: load
30: power inverter
40: switch
100: control unit
110: filter unit
120: converter
130: pressure reducing unit
140: power storage
151: first transformer
152: second transformer

Claims (10)

In the power converter connected to the grid and the load, stores the voltage input from the grid, and supplies the stored voltage to the load,
A power storage unit charging a voltage from the system;
Disposed between the grid and the power storage unit, and converts and outputs an AC voltage input from the grid in a first condition into a DC voltage, and converts a DC voltage input from the power storage unit into an AC voltage in a second condition. A conversion unit operating in both directions;
Disposed between the converter and the power storage unit, the DC voltage output from the converter under the first condition is reduced and transferred to the power storage unit, and the DC voltage supplied from the power storage unit is boosted under the second condition. A booster for transmitting to the converter; And
It includes a power supply unit for supplying a power voltage to each component constituting the power conversion device,
The power supply unit,
A first transformer having a primary side connected to the grid and a secondary side connected to each of the components; And
A second transformer having a structure in which a primary side is connected to the power storage unit, a secondary side is connected to a primary side of the first transformer, and has a symmetry with the first transformer,
The first transformer,
Receiving an AC voltage from the system at the first operation of the power conversion device, using the received AC voltage to generate and output an initial power supply voltage required for the initial operation of each component,
After the initial power supply voltage is output, generates and outputs a power supply voltage for each component based on the DC voltage supplied from the second transformer,
The second transformer,
And receiving a DC voltage from the power storage unit after the initial power supply voltage is output, and dividing the received DC voltage to transfer the DC voltage to the first transformer. delete The method of claim 1,
And the first transformer divides the voltage from the second transformer and supplies the power voltage to each of the components after the system is separated. delete The method of claim 1,
And the first transformer and the second transformer are flyback converters. A driving method of a power converter connected to a grid and a load, storing a voltage input from the grid, and supplying the stored voltage to the load,
Applying a grid output voltage from the grid to a first transformer during initial operation of the power converter;
Generating and outputting, by the first transformer, an initial power supply voltage required for initial operation of each component of the power converter using the grid output voltage;
Applying a DC voltage from a power storage unit to a second transformer after the initial power supply voltage is output;
Dividing the DC voltage in the second transformer and transferring the DC voltage to the first transformer; And
Generating a power supply voltage of each of the components by dividing the DC voltage transmitted from the second transformer by the first transformer,
The first transformer is
The primary side is connected to the grid, the secondary side is connected to each of the components,
The second transformer is
And a primary side connected to the power storage unit, a secondary side connected to a primary side of the first transformer, and having a structure symmetrical with the first transformer. delete delete delete The method of claim 6,
And the first transformer and the second transformer are flyback converters.

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