KR102314048B1 - Apparatus and Method for converting power intelligently - Google Patents

Abstract

Disclosed is an intelligent power conversion device that can be linked to the output side of an existing transformer and can maintain a voltage by power conversion of a PWM (Pulse Width Modulation) method. The intelligent power conversion device, a plurality of unit modules are individually selectively configured, a unit power conversion unit that converts power, and controls the unit power conversion unit, connected or disconnected by a detachable method with the unit power conversion unit It is characterized in that it includes a main control unit.

Description

Apparatus and Method for converting power intelligently}

The present invention relates to a power distribution transformer technology, and more particularly, to an intelligent power conversion device and method that can be linked to the output side of an existing transformer and can maintain a voltage through PWM (Pulse Width Modulation) power conversion. .

In addition, the present invention relates to an intelligent power conversion device and method that uses only a core, a coil, etc., which are the core of power conversion among existing transformers, and can remove internal/external additional elements.

Currently, distribution transformers adjust the number of turns through internal tap switching, but switching is done by opening the enclosure and putting your hand inside the insulating oil. Therefore, soundness, workability, etc. are very poor, and there are disadvantages in that it is difficult to apply an on-load tap changer (OLTC) due to problems such as size and price.

Protection facilities such as fuse and COS (Cut Out Switch) that are opened when secondary side failure occurs must be equipped and installed, and there is a problem that other protection devices or functions such as power quality compensation cannot be implemented.

In addition, the semiconductor switching type power conversion device has not been used due to high cost in the past, but in recent years, price and stability have been remarkably improved and competitiveness has been secured. Therefore, there is a need to maintain voltage by power conversion and use only the core and coil, which are the core of power conversion among existing transformers, and to be able to remove internal/external additional elements.

1. Korea Registered Utility Model No. 20-0347104 (Registration Date: March 29, 2004) 2. Korean Patent No. 10-1273354 (Registration Date: 2013.06.04)

The present invention is proposed to solve the problem according to the above background technology, and can be linked to the output side of an existing transformer, and provides an intelligent power conversion device and method capable of maintaining voltage by power conversion of a PWM (Pulse Width Modulation) method. Its purpose is to provide

In addition, an object of the present invention is to provide an intelligent power conversion device and method that uses only a core, a coil, etc., which are the core of power conversion among existing transformers, and can remove internal/external additional elements.

The present invention provides an intelligent power conversion device that can be linked to the output side of an existing transformer and can maintain a voltage by power conversion of a PWM (Pulse Width Modulation) method in order to achieve the task presented above.

The intelligent power conversion device,

a unit power converter configured to individually select a plurality of unit modules and convert power;

and a main control unit that controls the unit power conversion unit and is connected to or disconnected from the unit power conversion unit by a detachable method.

In this case, the unit module includes: a switching circuit for converting power; and a filter circuit that removes noise from the converted power.

In addition, the switching circuit is characterized in that the power is converted into at least one of alternating current (AC) power and direct current (DC) power.

In addition, the switching circuit is characterized in that it includes a DAB (Dual Active Bridge) type converter for bidirectional transmission.

In addition, the switching circuit is characterized in that it is controlled through a zero voltage or zero current switching technique for bidirectional transmission.

In addition, the switching circuit is characterized in that it is controlled using a PWM (Pulse Width Modulation) signal.

In addition, it is characterized in that the plurality of unit modules are connected in parallel.

In addition, the main control unit, a central processing unit for controlling the unit module; an input unit for inputting a user's command for the control; and a communication unit communicating with an external controller for remote control during the control.

In addition, the main control unit is characterized in that it is disposed in the cabinet body in which a plurality of insertion grooves are formed.

In addition, the unit module to be detachably attached to the insertion groove, it characterized in that it comprises a module body and a handle formed at the front end of the module body.

In addition, the module body is characterized in that it is inserted and fixed in the insertion groove through a slot method or a bushing method.

In addition, the number of turn-on units of the unit module is characterized in that it is calculated using the amount of power.

In addition, the amount of power is calculated at the same time as the load is supplied after all of the unit modules are turned on at the initial stage of driving.

In addition, the amount of power is calculated at the same time as the load is supplied after all of the unit modules are turned on at the initial stage of driving.

In addition, the number of turned-on units of the unit modules is the power surplus obtained by subtracting instantaneous power from the rated power of all unit modules in which the power surplus is currently turned on in order to maintain a preset first reference ratio among the rated powers of the entire unit modules. If it is less than 1 reference ratio, it is characterized in that it is increased by one.

In addition, the number of turn-on units of the unit modules is greater than the second reference ratio by adding the first reference ratio to the power margin obtained by subtracting the instantaneous power from the rated power of all unit modules that are currently turned on. do.

On the other hand, another embodiment of the present invention comprises the steps of (a) the main control unit is connected or released by a detachable method with a unit power conversion unit in which a plurality of unit modules are individually selectively configured; (b) controlling the unit power converter by the main controller; and (c) converting power by the unit power conversion unit according to the control; provides an intelligent power conversion method comprising: a.

According to the present invention, it is possible to improve usability, reliability, etc. by excluding additional functions of the distribution transformer, and to secure the voltage stability of the consumer, the improvement of the transmission distance, the reduction of the fault section, and the quality of the grid voltage.

In addition, as another effect of the present invention, it is possible to secure effects such as cost reduction, blackout suppression, efficiency and reliability improvement by implementing a parallel modular method.

In addition, as another effect of the present invention, when the load demand exceeds the rated power of the device or when a central command is received, the voltage can be lowered to a certain level to reduce the inactive load amount.

In addition, as another effect of the present invention, the DER-AVM (Distributed Energy Resource Active Voltage Manager) function is implemented to monitor the voltage of the distributed power installation point and, when out of the grid voltage regulation range, the For example, it is possible to control the output power factor of the distributed power supply by issuing a control command to the inverter for power factor control.

1 is a conceptual diagram of a power conversion device for single-phase transformation of a modular method according to an embodiment of the present invention.
2 is a conceptual diagram of a power conversion device for three-phase transformation of a modular method according to an embodiment of the present invention.
3 is a conceptual diagram in which the power conversion device shown in FIG. 1 is applied to an existing transformer.
FIG. 4 is a block diagram of the power conversion device shown in FIG. 3 .
5 is an example in which the power conversion device shown in FIG. 3 is applied to the end of a line.
6 is an example in which the power conversion device shown in FIG. 3 is applied to line interruption.
7 is an example of a power conversion circuit diagram of the power conversion device shown in FIG.
8 is an implementation example of a voltage/current control algorithm for controlling the power conversion circuit shown in FIG. 7 according to an embodiment of the present invention.
9 is a flowchart illustrating a process of calculating the number of turn-on unit modules according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals are used for like elements. The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. shouldn't

Hereinafter, an intelligent power conversion apparatus and method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of a power conversion apparatus 100 for single-phase transformation of a modular method according to an embodiment of the present invention. Referring to FIG. 1 , the power conversion device 100 includes a cabinet body 110 in the form of a cabinet, and first to third unit modules 120-1 to 120-3 detachable from the cabinet body 110 . can be configured.

An insertion groove 111 is formed in the cabinet body 110 to insert the first to third unit modules 120-1 to 120-3. The first to third unit modules 120-1 to 120-3 are configured in a modular manner, and the first to third unit modules 120-1 to 120-3 include the module body 120-3-1 and It is composed of a handle (120-3-2). Of course, inside the insertion groove 111 formed in the space of the cabinet body 110, a male terminal (not shown) formed to protrude from the ends of the first to third unit modules 120-1 to 120-3 is inserted. A female terminal (not shown) may be formed.

Of course, the male and female terminals are each composed of a pair of a negative electrode and a positive electrode, and the pair of male and female terminals may be arranged at regular intervals. Of course, the male and female terminals may be configured in reverse. That is, the female terminal may be formed to protrude from the ends of the first to third unit modules 120-1 to 120-3, and the male terminal may be formed inside the insertion groove 111. The female terminal may be a slot type. In addition, a bushing type in which wiring work is minimized may be used for coupling the first to third unit modules 120-1 to 120-3 and the cabinet body 110 .

The first to third unit modules 120-1 to 120-3 shown in FIG. 1 represent a single phase. In addition, the coupling of the first to third unit modules 120-1 to 120-3 and the cabinet body 110 is a bushing type in which wiring work is minimized, so that detachment is easy.

2 is a conceptual diagram of a power conversion device 200 for three-phase transformation of a modular method according to an embodiment of the present invention. Referring to FIG. 2 , in the cabinet body 110 , first to third unit modules 220-1 to 220-3 are configured in one phase 220 to indicate three phases.

The surface of the cabinet body 110 and the module body 120-3-1 may be coded for waterproofing and dustproofing so as not to be affected by fine dust in the rain. A nano-spray coating method may be used. The material may be urethane, silicone, or the like. In addition, the cabinet bodies 110 and 210 may be installed on electric poles using fasteners for fastening.

As shown in FIGS. 1 and 2 , if the same unit module is manufactured and corresponding to various capacities by number, the price of the device can be greatly reduced, and only one unit module corresponding to the unit module can be simply replaced in case of failure. It is very advantageous for quick repair. That is, this is because the unit module performs only the power conversion function, and the cabinet bodies 110 and 210 are divided to mount the operation and control system.

3 is a conceptual diagram in which the power conversion device 100 shown in FIG. 1 is applied to an existing transformer 310 . Referring to FIG. 3 , in a state in which the existing transformer 310 is already installed, the power conversion device 100 according to an embodiment of the present invention may be additionally installed. Existing transformer 310 receives 22.9kV of power transmitted by step-down and converts it to AC (Alternating Current) 154 to 286V and supplies it to the power conversion device 100, the power conversion device 100 is AC 220V or DC (Direct Current) ) to 450V. In particular, the output voltage of the power conversion device 100 is controlled by remote control.

FIG. 4 is a block diagram of the power conversion device 100 shown in FIG. 3 . In terms of circuitry, the power conversion device 100 is divided so that the unit module performs only a power conversion function, and the cabinet bodies 110 and 210 are equipped with an operation and control system. Referring to FIG. 4 , the power conversion device 100 may include a main control unit 410 and a unit power conversion unit 420 connected to the main control unit 410 to convert power according to control, etc. can

In the unit power conversion unit 420, the unit modules 120-1, 120-2, ... are selectively configured, and the individual unit modules convert power. The unit modules 120-1, 120-2, ... are a switching circuit 421 that performs a conversion function to increase or decrease power, and a filter circuit 422 that removes noise from the converted power after the conversion function is performed. can be composed of

The main control unit 410 includes a central processing unit 411 for controlling the unit modules 120-1, 120-2, ..., an input unit 412 for inputting a user's command, and an external controller 413 for remote control. It may be configured to include a communication unit 414 for communicating with, a storage unit 415 for storing setting information, programs, and data, a display unit 416 for displaying a setting screen, and the like.

The central processing unit 411 may be configured with a microprocessor, a microcomputer, and the like, and an algorithm for calculating the number of turn-on modules may be programmed as the unit module is detached. Accordingly, the central processing unit 411 may be implemented in software and/or hardware. In hardware implementation, an application specific integrated circuit (ASIC), digital signal processing (DSP), programmable logic device (PLD), field programmable gate array (FPGA), processor, microprocessor, or other It may be implemented as an electronic unit or a combination thereof. In software implementation, software composition component (element), object-oriented software composition component, class composition component and task composition component, process, function, attribute, procedure, subroutine, segment of program code, driver, firmware, microcode, data , databases, data structures, tables, arrays, and variables. Software, data, etc. may be stored in a memory and executed by a processor. The memory or processor may employ various means well known to those skilled in the art.

The input unit 412 includes a button, a touch screen, a speaker, and the like, and may receive a user's voice, motion, and the like.

The storage unit 415 performs a function of storing setting information, programs, software, processed data, and the like. To this end, the storage unit 415 may be a memory provided in the central processing unit 411 or may be a separate memory. Therefore, flash memory disk (SSD: Solid State Disk), hard disk drive, flash memory, EEPROM (Electrically erasable programmable read-only memory), SRAM (Static RAM), FRAM (Ferro-electric RAM), PRAM (Phase-change RAM) ), composed of a combination of non-volatile memory such as MRAM (Magnetic RAM) and/or volatile memory such as Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate-SDRAM (DDR-SDRAM), etc. can be

The display unit 416 may be a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display panel (PDP), an organic LED (OLED) display, a touch screen, a flexible display, or the like.

The communication unit 414 may be communicatively connected to the external controller 413 using wired/wireless communication. To this end, a communication circuit element, a processor, or the like may be configured. Communication connection is low/high speed PLC (Power Line Communication), ZigBee, RS-485, USB (Universal Serial Bus) communication, Wifi (Wireless Fidelity), WiSUN (Wireless Smart Utility Network), LoRa, NB-lOT (NarrowBand-Internet) of Things) may be used.

Therefore, the output maintains the set value even if the input side voltage fluctuates by a large width (about ±30%), and the operator can easily change it by using the wired/wireless control system according to the system situation. In addition, it is possible to replay and/or analyze an event voltage/current waveform when an abnormality occurs using the data collected through the display unit 416 . In addition, it is possible to provide time information by applying its own Global Positioning System (GPS) or a Real time clock (RTC) module including a secondary battery.

FIG. 5 is an example in which the power conversion devices 100 and 200 shown in FIG. 3 are applied to the end of a line. Referring to FIG. 5 , the power conversion device 100 is installed on the telephone pole 50 to simultaneously supply AC power and DC power. DC power is supplied to the charger 510 , and AC power is supplied directly to the consumer 520 . The charger 510 may be a charger for an electric vehicle, a charger for an Energy Storage System (ESS), or the like. Of course, the charger 510 may be connected to the solar power generation 530 to supply power to the consumer 520 . Of course, the power conversion device 100 may be connected to the existing transformer 310 .

FIG. 6 is an example of applying the power conversion apparatus 100 and 200 shown in FIG. 3 to line interruption. Referring to FIG. 6 , the power conversion device 100 is installed on an intermediate line. Of course, in this case, it is not connected to the existing transformer 310, and only the power conversion device 100 may be installed alone. 5 and 6, the effect of increasing the voltage stability of the consumer and/or the transmission distance of the low voltage line can be secured.

FIG. 7 is an example of a power conversion circuit diagram of the power conversion apparatuses 100 and 200 shown in FIG. 3 . Referring to FIG. 7 , the power conversion circuit may include a switching circuit 421 and a filter circuit 422 . The switching circuit 421 converts power through a converter in which the switching element 710 is configured. In addition, by including the transformer 740, high AC power -> low AC power, AC power -> conversion is made to DC power. The converter may be a DAB (Dual Active Bridge) type converter for bidirectional transmission. In addition, the switching device 710 may be a SiC power semiconductor, a field effect transistor (FET), a metal oxide semiconductor FET (MOSFET), an insulated gate bipolar mode transistor (IGBT), a power rectifying diode, or the like.

The transformer 740 may be a nano-crystalline core high-frequency transformer. In addition, it is possible to maintain a bidirectional power conversion efficiency of 97% or more at the rating by using a zero voltage/zero current switching technique. The filter circuit 422 may include an inductor 730 and a capacitor 720 .

8 is an implementation example of a voltage/current control algorithm for controlling the power conversion circuit shown in FIG. 7 according to an embodiment of the present invention. Referring to FIG. 8 , the voltage control 810 and the current control 820 are summed by an adder to generate PWM signals S1 , S2 , S3 , and S4 by a pulse width modulation (PWM) generator 830 . Of course, FIG. 8 is an example, and various algorithms are possible.

9 is a flowchart illustrating a process of calculating the number of turn-on unit modules according to an embodiment of the present invention. Referring to FIG. 9 , all unit modules 120-1 to 120-3 and 220-1 to 220-3 are turned on in the initial stage of operation, a load is supplied, and an amount of power is calculated at the same time to calculate the appropriate number of turn-on unit modules. (steps S910 and S920). When the appropriate number of turn-on unit modules is calculated, the excess unit modules are turned off (step S930).

The power margin should be maintained at 10% of the rated power of the unit module. 10% is an example, and the number may vary depending on the specifications of the power conversion device. This can be expressed as a mathematical expression as follows.

If the unit module capacity is 20kVA, a power margin of 2kVA or more must be maintained. Therefore, when the power margin is less than the set value (10% of the unit module capacity), one unit module is additionally turned on (steps S940 and S941).

Conversely, when the power margin of the currently turned-on unit module becomes 110% or more by adding the spare set value (10%) to the unit module capacity, one module is turned off (steps S950, S960, and S961).

In addition, the steps of the method or algorithm described in connection with the embodiments disclosed herein are implemented in the form of program instructions that can be executed through various computer means such as a microprocessor, a processor, a CPU (Central Processing Unit), etc. It can be recorded on any available medium. The computer-readable medium may include program (instructions) codes, data files, data structures, etc. alone or in combination.

The program (instructions) code recorded on the medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs, DVDs, Blu-rays, and the like, and ROM, RAM ( A semiconductor memory device specially configured to store and execute program (instruction) code such as RAM), flash memory, and the like may be included.

Here, examples of the program (instruction) code include not only machine language codes such as those generated by a compiler but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

100: intelligent power conversion device
110: cabinet body
111: insertion groove
120-1,120-2,120-3: first to third unit modules
120-3-1: module body
120-3-2: handle

Claims (17)

A plurality of unit modules (120-1 to 120-3, 220-1 to 220-3) are individually selectively configured, the unit power conversion unit 420 for converting power;
and a main control unit 410 that controls the unit power conversion unit 420 and is connected or disconnected with the unit power conversion unit 420 by a detachable method;
The number of turn-ons of the unit modules 120-1 to 120-3 is calculated using the amount of power,
The amount of power is calculated at the same time as the load is supplied after all of the unit modules 120-1 to 120-3 are turned on at the initial stage of operation,
Intelligent power conversion device, characterized in that the unit modules (120-1 to 120-3) exceeding the calculated turn-on number is turned off.
The method of claim 1,
The unit modules (120-1 to 120-3, 220-1 to 220-3),
a switching circuit 421 for converting power; and
Intelligent power conversion device comprising a; filter circuit 422 for removing noise from the converted power.
3. The method of claim 2,
The switching circuit 421, the intelligent power conversion device, characterized in that for converting the power into at least one of AC (Alternating Current) power and DC (Direct Current) power.
4. The method of claim 3,
The switching circuit 421 is an intelligent power conversion device, characterized in that it comprises a DAB (Dual Active Bridge) type converter for bidirectional transmission.
5. The method of claim 4,
The switching circuit 421 is an intelligent power conversion device, characterized in that controlled through a zero voltage or zero current switching technique for bidirectional transmission.
6. The method of claim 5,
The switching circuit 421 is an intelligent power conversion device, characterized in that controlled using PWM (Pulse Width Modulation) signals (S1 to S4).
The method of claim 1,
The plurality of unit modules (120-1 to 120-3, 220-1 to 220-3) are intelligent power conversion device, characterized in that connected in parallel. The method of claim 1,
The main control unit 410 is
a central processing unit 411 for controlling the unit modules 120-1 to 120-3 and 220-1 to 220-3;
an input unit 412 for inputting a user's command for the control; and
Intelligent power conversion device comprising a; communication unit (414) that communicates with the external controller (413) for remote control during the control.
The method of claim 1,
The main control unit (410) is an intelligent power conversion device, characterized in that disposed in the cabinet body (110) in which a plurality of insertion grooves (111) are formed.
10. The method of claim 9,
The unit modules 120-1 to 120-3 are detachably attached to the insertion groove 111,
Intelligent power conversion device comprising a module body (120-3-1) and a handle (120-3-2) formed at the front end of the module body (120-3-1).
11. The method of claim 10,
The module body (120-3-1) is an intelligent power conversion device, characterized in that inserted and fixed in the insertion groove (111) through a slot method or a bushing method.
delete delete delete The method of claim 1,
The number of turn-on units of the unit modules 120-1 to 120-3 is the amount of power margin currently turned on in order to maintain a preset first reference ratio among the rated power of the unit modules 120-1 to 120-3. Intelligent power conversion device, characterized in that if the power margin by subtracting the instantaneous power from the rated power of the entire unit module is less than the first reference ratio, one is increased.
16. The method of claim 15,
The number of turn-on units of the unit modules 120-1 to 120-3 is equal to or greater than the second reference ratio by adding the first reference ratio to the power margin obtained by subtracting the instantaneous power from the rated power of all unit modules currently turned on. Intelligent power conversion device, characterized in that the number is reduced.
(a) the main control unit 410 is connected by a detachable method with the unit power conversion unit 420 in which a plurality of unit modules (120-1 to 120-3, 220-1 to 220-3) are individually selectively configured or being released;
(b) the main control unit 410 controlling the unit power conversion unit 420; and
(c) converting, by the unit power converter 420, power according to the control;
The number of turn-ons of the unit modules 120-1 to 120-3 is calculated using the amount of power,
The amount of power is calculated at the same time as the load is supplied after all of the unit modules 120-1 to 120-3 are turned on at the initial stage of operation,
The intelligent power conversion method, characterized in that the unit modules (120-1 to 120-3) exceeding the calculated turn-on number are turned off.

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