KR20210099813A - High voltage dc-dc converter for electric vehicle - Google Patents

High voltage dc-dc converter for electric vehicle Download PDF

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KR20210099813A
KR20210099813A KR1020200013632A KR20200013632A KR20210099813A KR 20210099813 A KR20210099813 A KR 20210099813A KR 1020200013632 A KR1020200013632 A KR 1020200013632A KR 20200013632 A KR20200013632 A KR 20200013632A KR 20210099813 A KR20210099813 A KR 20210099813A
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unit
converter
converter unit
voltage
electric vehicle
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Korean (ko)
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금문환
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주식회사 만도
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/20—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by converters located in the vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/20—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by converters located in the vehicle
    • B60L53/24—Using the vehicle's propulsion converter for charging
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0083—Converters characterised by their input or output configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2210/00—Converter types
    • B60L2210/10—DC to DC converters
    • B60L2210/12—Buck converters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/90—Vehicles comprising electric prime movers
    • B60Y2200/91—Electric vehicles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles

Abstract

The present invention relates to a DC/DC converter of a two-stage structure for a high-voltage electric vehicle. According to the present invention, the DC/DC converter is connected and controlled by a two-stage structure of a buck converter and an LLC resonant converter to cope with a system of an electric vehicle battery which has been raised to 800V so as to reduce the number of SiC power semiconductors, thereby saving costs.

Description

전기자동차용 고전압 DC-DC 컨버터{HIGH VOLTAGE DC-DC CONVERTER FOR ELECTRIC VEHICLE}High voltage DC-DC converter for electric vehicle

본 발명은 전기자동차에 관한 것으로, 특히 고전압을 사용하는 전기자동차의 DC-DC 컨버터에 관한 것이다.The present invention relates to an electric vehicle, and more particularly, to a DC-DC converter of an electric vehicle using a high voltage.

전기자동차에는 두 가지 전압의 배터리가 공존한다. 400V의 전압을 가지는 HV(High Voltage) 배터리와 13.9V의 전압을 가지는 LV(Low Voltage) 배터리가 그것이다. In an electric vehicle, batteries of two voltages coexist. They are a high voltage (HV) battery having a voltage of 400V and a low voltage (LV) battery having a voltage of 13.9V.

HV 배터리는 인버터를 통해 전기자동차가 움직이는데 필요한 구동모터에 전력을 공급한다. LV 배터리는 전기자동차의 전자장비에 12V 시스템 전원을 공급한다. LDC(Low-Side DC/DC Converter)는 고전압의 HV 배터리에서 전원을 공급받아 저전압의 LV 배터리에 전원을 공급하기 위해 전압을 변환하는 역할을 한다.The HV battery supplies power to the driving motor needed to move the electric vehicle through an inverter. The LV battery supplies the 12V system power to the electronic equipment of the electric vehicle. LDC (Low-Side DC/DC Converter) receives power from high voltage HV battery and converts voltage to supply power to low voltage LV battery.

도 1은 종래의 전기자동차 시스템에 사용되는 LDC의 한 예이다.1 is an example of an LDC used in a conventional electric vehicle system.

종래기술에서는 일반적으로 PSFB(Phase Shift Full Bridge) 컨버터가 사용된다. PSFB 컨버터는 ZVS(Zero Voltage Switching)이 가능하기 때문에 널리 사용된다. 스위칭소자가 on/off 전환 시 짧은 순간에 동시에 On상태가 되면 손실이 발생하기 때문에 스위칭 전 스위칭 소자를 0인 상태로 만들어놓은 후 다음 스위칭 소자를 On으로 하는 ZVS를 사용하면 이와 같은 손실을 방지할 수 있다. 따라서 PSFB 컨버터는 효율을 높일 수 있다. 또한 큰 전류가 흐르는 이차측 다이오드에 동일한 전류가 흐르기 때문에 다이오드 부담이 적은 것도 PSFB 컨버터가 많이 사용되는 또 다른 이유이다.In the prior art, a phase shift full bridge (PSFB) converter is generally used. PSFB converters are widely used because ZVS (Zero Voltage Switching) is possible. Loss occurs when switching elements are turned on at the same time in a short moment when switching on/off. can Therefore, the PSFB converter can increase the efficiency. In addition, since the same current flows through the secondary side diode through which a large current flows, the diode load is low, which is another reason why PSFB converters are widely used.

하지만 전기자동차의 주행거리를 늘리기 위해 HV 배터리의 전압을 400V에서 800V로 높이면서 더 이상 PSFB 컨버터를 사용하기 곤란한 상황이 되었다. PSFB 컨버터가 넓은 입출력범위를 대응할 수 없고, 트랜스포머의 사이즈가 증가하고 SiC 전력반도체 사용이 늘어나면서 비용 또한 증가하는 문제가 있기 때문이다.However, as the voltage of the HV battery was increased from 400V to 800V to increase the mileage of electric vehicles, it became difficult to use the PSFB converter any longer. This is because the PSFB converter cannot cope with a wide input/output range, and as the size of the transformer increases and the use of SiC power semiconductor increases, the cost also increases.

본 발명의 발명자들은 이러한 종래 기술의 LDC의 문제점을 해결하기 위해 노력해 왔다. 이중 구조로 800V 이상의 고전압 배터리 시스템에서도 안정적으로 동작하면서도 비용은 줄일 수 있는 LDC를 완성하기 위해 많은 노력 끝에 본 발명을 완성하기에 이르렀다.The inventors of the present invention have been trying to solve these problems of the LDC of the prior art. The present invention has been completed after much effort to complete an LDC that can stably operate even in a high voltage battery system of 800V or higher with a dual structure while reducing the cost.

본 발명의 목적은 종래 PSFB 구조의 DC/DC 컨버터가 대응할 수 없었던 넓은 입출력 범위에 대응할 수 있는 LDC를 제공함에 있다. It is an object of the present invention to provide an LDC capable of responding to a wide input/output range that the conventional DC/DC converter of the PSFB structure could not cope with.

한편, 본 발명의 명시되지 않은 또 다른 목적들은 하기의 상세한 설명 및 그 효과로부터 용이하게 추론 할 수 있는 범위 내에서 추가적으로 고려될 것이다.On the other hand, other objects not specified in the present invention will be additionally considered within the range that can be easily inferred from the following detailed description and effects thereof.

본 발명에 따른 전기자동차용 2단 구조의 LDC(Low-Side DC/DC Converter)는, LDC (Low-Side DC/DC Converter) of a two-stage structure for an electric vehicle according to the present invention,

입력 전압을 제공하는 입력부; 상기 입력 전압을 강압하여 전압을 낮추는 벅(Buck) 컨버터부; 상기 낮춰진 전압을 강압하고 상기 벅 컨버터부로부터 전기적으로 절연시키는 DC/DC 컨버터부; 및 상기 DC/DC 컨버터부에서 강압된 전압을 출력하는 출력부;가 순서대로 연결되어 포함되고, 상기 벅 컨버터부와 DC/DC 컨버터부의 스위칭을 제어하는 제어부;를 포함하는 것을 특징으로 한다.an input providing an input voltage; a buck converter unit for step-down the input voltage to lower the voltage; a DC/DC converter for stepping down the lowered voltage and electrically insulating from the buck converter; and an output unit for outputting the voltage step-down from the DC/DC converter unit; a control unit configured to be sequentially connected and included, and control switching of the buck converter unit and the DC/DC converter unit.

상기 DC/DC 컨버터부는 PSFB(Phase Shift Full-Bridge) 컨버터일 수 있다.The DC/DC converter may be a Phase Shift Full-Bridge (PSFB) converter.

또한, 상기 DC/DC 컨버터부는 LLC(Inductor-Inductor-Capacitor) 공진 컨버터일 수 있다. Also, the DC/DC converter unit may be an inductor-inductor-capacitor (LLC) resonant converter.

본 발명의 다른 실시예에 따른 전기자동차용 2단 구조의 LDC(Low-Side DC/DC Converter)는,LDC (Low-Side DC/DC Converter) of a two-stage structure for an electric vehicle according to another embodiment of the present invention,

입력 전압을 제공하는 입력부; 상기 입력 전압을 강압하여 낮추고 상기 입력부와 전기적으로 절연시키는 LLC 컨버터부; 상기 LLC 컨버터부에서 강압된 전압을 변환하는 벅(Buck) 컨버터부; 및 상기 벅 컨버터부에서 변환된 전압을 출력하는 출력부;가 순서대로 연결되어 포함되고, 상기 LLC 컨버터부와 벅 컨버터부의 스위칭을 제어하는 제어부;를 포함하는 것을 특징으로 한다.an input providing an input voltage; an LLC converter unit for step-down and lowering the input voltage and electrically insulates from the input unit; a buck converter unit for converting the voltage step-down in the LLC converter unit; and an output unit for outputting the voltage converted by the buck converter unit; a control unit for controlling switching of the LLC converter unit and the buck converter unit.

상기 제어부는 상기 LLC 컨버터부를 제어하는 제1 제어부와 상기 벅 컨버터부를 제어하는 제2 제어부로 구성되는 것을 특징으로 한다.The control unit is characterized in that it is composed of a first control unit for controlling the LLC converter unit and a second control unit for controlling the buck converter unit.

상기 LLC 컨버터부는 공진주파수로만 동작하여 입력전압에 비례하여 출력전압이 생성될 수 있다.The LLC converter unit operates only at a resonance frequency to generate an output voltage in proportion to an input voltage.

바람직하게는 상기 제어부는 상기 LLC 컨버터부의 출력전압의 변화에 따라 벅 컨버터부의 스위칭 주파수를 제어하여 상기 출력부의 출력전압이 일정하도록 제어하는 것이 좋다.Preferably, the control unit controls the switching frequency of the buck converter unit according to a change in the output voltage of the LLC converter unit so that the output voltage of the output unit is constant.

본 발명에 따르면 2단으로 구성된 LDC 구조에서 앞단은 입력전압의 변화를 감당하고, 출력의 변화는 뒷단에서 나누어 감당하므로 시스템의 안정성이 증가하는 효과가 있다. According to the present invention, in the LDC structure composed of two stages, the front stage handles the input voltage change, and the rear stage handles the change in the output voltage, so the stability of the system is increased.

또한 SiC 전력반도체의 사용을 줄일 수 있으므로 시스템 전체의 비용을 줄일 수 있는 장점도 있다.In addition, since the use of SiC power semiconductors can be reduced, there is an advantage of reducing the overall cost of the system.

한편, 여기에서 명시적으로 언급되지 않은 효과라 하더라도, 본 발명의 기술적 특징에 의해 기대되는 이하의 명세서에서 기재된 효과 및 그 잠정적인 효과는 본 발명의 명세서에 기재된 것과 같이 취급됨을 첨언한다.On the other hand, even if it is an effect not explicitly mentioned herein, it is added that the effects described in the following specification expected by the technical features of the present invention and their potential effects are treated as described in the specification of the present invention.

도 1은 종래기술에 따른 LDC의 한 예이다.
도 2는 본 발명의 바람직한 어느 실시예에 따른 DC/DC 컨버터의 구성도이다.
도 3은 본 발명의 바람직한 어느 실시예에 따른 DC/DC 컨버터의 상세 구성도이다.
도 4는 본 발명의 바람직한 다른 실시예에 따른 DC/DC 컨버터의 구성도이다.
도 5는 본 발명의 바람직한 다른 실시예에 따른 DC/DC 컨버터의 상세 구성도이다.
※ 첨부된 도면은 본 발명의 기술사상에 대한 이해를 위하여 참조로서 예시된 것임을 밝히며, 그것에 의해 본 발명의 권리범위가 제한되지는 아니한다1 is an example of an LDC according to the prior art.
2 is a block diagram of a DC/DC converter according to a preferred embodiment of the present invention.
3 is a detailed configuration diagram of a DC/DC converter according to a preferred embodiment of the present invention.
4 is a block diagram of a DC/DC converter according to another preferred embodiment of the present invention.
5 is a detailed configuration diagram of a DC/DC converter according to another preferred embodiment of the present invention.
※ It is revealed that the accompanying drawings are exemplified as a reference for understanding the technical idea of the present invention, and the scope of the present invention is not limited thereby

이하, 도면을 참조하여 본 발명의 다양한 실시예가 안내하는 본 발명의 구성과 그 구성으로부터 비롯되는 효과에 대해 살펴본다. 본 발명을 설명함에 있어서 관련된 공지기능에 대하여 이 분야의 기술자에게 자명한 사항으로서 본 발명의 요지를 불필요하게 흐릴 수 있다고 판단되는 경우에는 그 상세한 설명을 생략한다. Hereinafter, with reference to the drawings, the configuration of the present invention guided by various embodiments of the present invention and effects resulting from the configuration will be described. In the description of the present invention, if it is determined that the subject matter of the present invention may be unnecessarily obscured as it is obvious to those skilled in the art with respect to related known functions, the detailed description thereof will be omitted.

'제1', '제2' 등의 용어는 다양한 구성요소를 설명하는데 사용될 수 있지만, 상기 구성요소는 위 용어에 의해 한정되어서는 안 된다. 위 용어는 하나의 구성요소를 다른 구성요소로부터 구별하는 목적으로만 사용될 수 있다. 예를 들어, 본 발명의 권리범위를 벗어나지 않으면서 '제1구성요소'는 '제2구성요소'로 명명될 수 있고, 유사하게 '제2구성요소'도 '제1구성요소'로 명명될 수 있다. 또한, 단수의 표현은 문맥상 명백하게 다르게 표현하지 않는 한, 복수의 표현을 포함한다. 본 발명의 실시예에서 사용되는 용어는 다르게 정의되지 않는 한, 해당 기술분야에서 통상의 지식을 가진 자에게 통상적으로 알려진 의미로 해석될 수 있다.Terms such as 'first' and 'second' may be used to describe various elements, but the elements should not be limited by the above terms. The above term may be 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'. can Also, the singular expression includes the plural expression unless the context clearly dictates otherwise. Unless otherwise defined, terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those of ordinary skill in the art.

이하, 도면을 참조하여 본 발명의 다양한 실시예가 안내하는 본 발명의 구성과 그 구성으로부터 비롯되는 효과에 대해 살펴본다.Hereinafter, with reference to the drawings, the configuration of the present invention guided by various embodiments of the present invention and effects resulting from the configuration will be described.

도 2는 본 발명의 바람직한 어느 실시예에 따른 2단 구조의 LDC의 구성도이다.2 is a block diagram of an LDC having a two-stage structure according to a preferred embodiment of the present invention.

본 발명의 2단 구조 LDC는 입력부(110), 벅 컨버터부(120), DC/DC 컨버터부(130), 출력부(140) 및 제어부(150)로 구성된다.The two-stage structure LDC of the present invention includes an input unit 110 , a buck converter unit 120 , a DC/DC converter unit 130 , an output unit 140 , and a control unit 150 .

입력부(110)는 800V의 고전압 전원을 입력받아 벅 컨버터부(120)로 전달한다.The input unit 110 receives the high voltage power of 800V and transmits it to the buck converter unit 120 .

벅 컨버터부(120)는 800V 고전압을 스위칭을 이용하여 저전압으로 강압하여 출력한다. 기존 전기자동차들은 400V 배터리 시스템을 사용했기 때문에 벅 컨버터부(120)의 출력을 400V로 하면 기존 시스템을 그대로 이용할 수 있는 장점이 있다.The buck converter unit 120 steps down the 800V high voltage to a low voltage using switching and outputs it. Existing electric vehicles use a 400V battery system, so if the output of the buck converter unit 120 is set to 400V, the existing system can be used as it is.

DC/DC 컨버터부(130)는 벅 컨버터부(120)의 출력전압인 400V를 변압기를 사용하여 절연하면서 동시에 13.9V의 전압으로 변환한다. DC/DC 컨버터부(130)에는 종래의 PSFB 컨버터 또는 LLC 공진 컨버터를 사용할 수 있다.The DC/DC converter unit 130 converts the 400V output voltage of the buck converter unit 120 into a voltage of 13.9V while insulating it using a transformer. A conventional PSFB converter or LLC resonant converter may be used for the DC/DC converter unit 130 .

도 3은 본 발명의 바람직한 어느 실시예에 따른 2단 구조의 LDC의 좀 더 자세한 구성도이다.3 is a more detailed configuration diagram of an LDC having a two-stage structure according to a preferred embodiment of the present invention.

벅 컨버터부(120)는 제1 스위치(M1), 제1 다이오드(D1), 벅인턱터, 벅캐패시터(Vdc)를 포함한다.The buck converter unit 120 includes a first switch M 1 , a first diode D 1 , a buck inductor, and a buck capacitor Vdc.

제1 스위치와 벅인덕터는 입력부(110)와 직렬로 연결되고, 제1 다이오드와 출력 전압이 저장되는 벅캐패시터는 입력부(110)와 병렬로 연결된다.The first switch and the buck inductor are connected in series with the input unit 110 , and the first diode and the buck capacitor in which the output voltage is stored are connected in parallel with the input unit 110 .

제1 스위치가 온(On)되어 있는 동안은 제1 다이오드에 전류가 흐르지 않고, 제1 스위치가 오프(Off)되어 있는 동안 벅캐패시터의 전원이 제1 다이오드로 흐르므로 제1 스위치의 스위칭 타이밍에 의해 벅컨버터부(120)의 출력 전압이 조절된다.Since no current flows to the first diode while the first switch is on, and power of the buck capacitor flows to the first diode while the first switch is off, the switching timing of the first switch By this, the output voltage of the buck converter unit 120 is adjusted.

DC/DC 컨버터부(130)는 PSFB 컨버터 또는 LLC 공진 컨버터가 사용된다. 도 3에서는 LLC 공진 컨버터의 예를 보여준다.The DC/DC converter unit 130 uses a PSFB converter or an LLC resonant converter. 3 shows an example of an LLC resonant converter.

벅 컨버터부(120)의 출력 전압(Vdc)에는 제2 스위치(M2)와 제3 스위치(M3)가 직렬로 연결된다. 공진 인덕터(Lr), 공진 캐패시터(Cr), 자화 인덕터(LM)는 서로 직렬로 연결되어 다시 제3 스위치에 병렬로 연결되고, 자화 인덕터에는 변압기가 병렬로 연결된다. 변압기의 출력측에는 제2 다이오드(D2)와 제3 다이오드(D3)가 직렬로 연결되고 제3 다이오드에는 출력 캐패시터(Co)가 직렬로 연결된다.A second switch (M 2 ) and a third switch (M 3 ) are connected in series to the output voltage (V dc ) of the buck converter unit 120 . The resonant inductor (L r ), the resonant capacitor (C r ), and the magnetizing inductor (L M ) are connected in series with each other and again connected in parallel to the third switch, and a transformer is connected to the magnetizing inductor in parallel. A second diode (D 2 ) and a third diode (D 3 ) are connected in series to the output side of the transformer, and an output capacitor (C o ) is connected in series to the third diode.

출력부(140)는 출력 캐패시터(Co)에서 13.9V로 변환된 출력전압(V0)이 출력되어 전기자동차의 전자장비들에 공급된다.The output unit 140 outputs the output voltage (V 0 ) converted from the output capacitor (C o ) to 13.9V and is supplied to the electronic devices of the electric vehicle.

제어부(150)는 출력전압(V0) 또는 벅 컨버터부(120)의 출력전압(Vdc)에 따라 벅 컨버터부(120) 또는 DC/DC 컨버터부(130)를 제어한다. 벅 컨버터부(120)의 제1 스위치의 스위칭 주기(Duty)를 가변하여 출력전압을 조절하는 것이다. 제어부(150)는 벅 컨버터부(120)를 제어하는 제1 제어부와 DC/DC 컨버터부(130)를 제어하는 제2 제어부로 구성될 수도 있다.The control unit 150 controls the buck converter unit 120 or the DC/DC converter unit 130 according to the output voltage (V 0 ) or the output voltage (V dc ) of the buck converter unit 120 . The output voltage is adjusted by varying the switching period (Duty) of the first switch of the buck converter unit 120 . The control unit 150 may include a first control unit for controlling the buck converter unit 120 and a second control unit for controlling the DC/DC converter unit 130 .

벅 컨버터부(120)는 SiC 전력반도체를 종래기술의 PSFB 컨버터에 비해 적게 사용하므로 비용절감의 효과를 얻을 수 있다. 또한 2단 구조임에도 PSFB 컨버터와 자성소자의 개수는 동일하다.Since the buck converter unit 120 uses less SiC power semiconductor than the PSFB converter of the prior art, the effect of cost reduction can be obtained. In addition, the number of PSFB converters and magnetic elements is the same despite the two-stage structure.

도 4는 본 발명의 바람직한 다른 실시예에 따른 2단 구조 LDC의 구성을 나타낸다.4 shows the configuration of a two-stage structure LDC according to another preferred embodiment of the present invention.

본 발명의 2단 LDC는 입력부(210), LLC 컨버터부(220), 벅 컨버터부(230) 및 출력부(240)가 순서대로 연결되며, LLC 컨버터부(220) 제어를 위한 제1 제어부(250)와 벅 컨버터부(230) 제어를 위한 제2 제어부(260)를 포함한다.In the two-stage LDC of the present invention, the input unit 210, the LLC converter unit 220, the buck converter unit 230, and the output unit 240 are sequentially connected, and a first control unit ( 250 and a second control unit 260 for controlling the buck converter unit 230 .

LLC 컨버터부(220)는 공진주파수를 결정하여 공진주파수로 LLC 컨버터부(220)를 설계한 후 항상 공진주파수로 동작하도록 할 수 있다. LLC 컨버터부(220)의 출력전압은 입력전압에 비례하여 결정되므로 LLC 컨버터부(220)의 제어가 필요없다. 공진주파수에서 동작하는 LLC 컨버터부(220)는 최대의 효율을 가지므로 제어 없이 공진주파수로 LLC 컨버터부(220)를 작동시키는 것이다.The LLC converter unit 220 may determine the resonant frequency to design the LLC converter unit 220 with the resonant frequency and then always operate at the resonant frequency. Since the output voltage of the LLC converter unit 220 is determined in proportion to the input voltage, the control of the LLC converter unit 220 is not required. Since the LLC converter unit 220 operating at the resonant frequency has maximum efficiency, the LLC converter unit 220 operates at the resonant frequency without control.

벅 컨버터부(230)는 LLC 컨버터부(220)의 출력전압을 스위칭 제어를 통해 강압하고 출력부(240)를 통해 출력한다. 제2 제어부(260)는 벅 컨버터부(230)의 스위칭 듀티 제어를 통해 출력전압을 조절한다.The buck converter unit 230 steps down the output voltage of the LLC converter unit 220 through switching control and outputs it through the output unit 240 . The second control unit 260 adjusts the output voltage through the switching duty control of the buck converter unit 230 .

제1 제어부와 제2 제어부는 하나의 제어부로 구성되는 것도 가능하다. LLC 컨버터부(220)가 항상 공진주파수로 동작하는 경우 제어부가 필요 없으므로 하나의 제어부에 의해 벅 컨버터부(230)만을 제어하는 것이다.The first control unit and the second control unit may be configured as one control unit. When the LLC converter unit 220 always operates at the resonant frequency, there is no need for a control unit, so only the buck converter unit 230 is controlled by one control unit.

도 5는 본 발명의 2단 LDC의 좀 더 자세한 구조를 나타낸다.5 shows a more detailed structure of the two-stage LDC of the present invention.

LLC 컨버터부(220)의 제1 스위치(M1)와 제2 스위치(M2)는 50:50의 듀티로 LLC 회로의 공진주파수에 따라 스위칭한다. 변압기에는 교류전원을 공급해야 하므로 제1 스위치와 제2 스위치가 번갈아 스위칭하며 직류전원을 교류전원으로 바꾸어 변압기에 공급한다. LLC 컨버터부(220)의 변압기(Trans)는 절연과 함께 턴수(n:1:1)에 의해 출력전압(Vdc)을 결정한다.The first switch (M 1 ) and the second switch (M 2 ) of the LLC converter unit 220 switch according to the resonance frequency of the LLC circuit with a duty of 50:50. Since AC power needs to be supplied to the transformer, the first switch and the second switch switch alternately, and the DC power is converted into AC power and supplied to the transformer. The transformer Trans of the LLC converter 220 determines the output voltage Vdc by the number of turns (n:1:1) together with insulation.

LLC 컨버터부(220)의 공진주파수는 변압기의 크기와 관련된다. 공진주파수가 커질수록 변압기의 크기는 줄일 수 있으나 제3 스위치의 스위칭 손실이 증가한다. 따라서 변압기의 크기와 스위치의 스위칭 손실 사이의 트레이드오프를 고려하여 LLC 컨버터부(220)의 공진주파수를 결정해야 한다.The resonance frequency of the LLC converter unit 220 is related to the size of the transformer. As the resonance frequency increases, the size of the transformer can be reduced, but the switching loss of the third switch increases. Therefore, it is necessary to determine the resonance frequency of the LLC converter unit 220 in consideration of the tradeoff between the size of the transformer and the switching loss of the switch.

벅 컨버터부(230)는 LLC 컨버터부(220)의 출력전압(Vdc)와 직렬로 연결된 제3 스위치(M3)와 다이오드를 포함하고, 출력 인덕터(Lo)와 출력 캐패시턴스(Co)가 순서대로 직렬로 연결되어 다이오드에 병렬로 연결된다. The buck converter unit 230 includes a third switch (M 3 ) and a diode connected in series with the output voltage (Vdc) of the LLC converter unit 220, the output inductor (L o ) and the output capacitance (C o ) They are connected in series in order and connected in parallel to the diode.

벅 컨버터부(230)는 스위치의 스위칭 듀티를 제어하여 출력전압(Vo)을 조절할 수 있다. 제2 제어부(260)가 제3 스위치(M3)의 스위칭 주기를 조절함으로써 출력전압을 조절하는 것이다. LLC 컨버터부(220)가 공진주파수에서만 동작하여 입력전압에 비례하는 출력전압만 내놓는다고 하더라도 벅 컨버터부(230)는 다양한 LLC 컨버터부 출력전압을 스위칭 제어를 통해 필요한 전압으로 변환할 수 있다. 이렇게 13.9V로 변환된 전원은 전기자동차의 전자장비에 공급된다.The buck converter unit 230 may control the switching duty of the switch to adjust the output voltage (V o ). The second control unit 260 adjusts the output voltage by adjusting the switching period of the third switch M 3 . Even if the LLC converter unit 220 operates only at the resonance frequency and outputs only an output voltage proportional to the input voltage, the buck converter unit 230 may convert various LLC converter unit output voltages into necessary voltages through switching control. The power converted to 13.9V in this way is supplied to the electronic equipment of the electric vehicle.

이상과 같은 본 발명에 따른 2단 구조의 LDC를 사용하면 800V로 입력전압이 높아진 전기자동차의 고전압 배터리 시스템에도 적용이 가능하고 SiC 전력반도체 소자 수를 줄임으로써 비용도 줄일 수 있는 효과가 있다.If the LDC of the two-stage structure according to the present invention as described above is used, it can be applied to a high-voltage battery system of an electric vehicle whose input voltage is increased to 800V, and there is an effect that the cost can be reduced by reducing the number of SiC power semiconductor elements.

본 발명의 보호범위가 이상에서 명시적으로 설명한 실시예의 기재와 표현에 제한되는 것은 아니다. 또한, 본 발명이 속하는 기술분야에서 자명한 변경이나 치환으로 말미암아 본 발명이 보호범위가 제한될 수도 없음을 다시 한 번 첨언한다.The protection scope of the present invention is not limited to the description and expression of the embodiments explicitly described above. In addition, it is added once again that the protection scope of the present invention cannot be limited due to obvious changes or substitutions in the technical field to which the present invention pertains.

Claims (8)

입력 전압을 제공하는 입력부;
상기 입력 전압을 강압하여 전압을 낮추는 벅(Buck) 컨버터부;
상기 낮춰진 전압을 강압하고 상기 벅 컨버터부로부터 전기적으로 절연시키는 DC/DC 컨버터부; 및
상기 DC/DC 컨버터부에서 강압된 전압을 출력하는 출력부;가 순서대로 연결되어 포함되고,
상기 벅 컨버터부와 DC/DC 컨버터부의 스위칭을 제어하는 제어부;를 포함하는 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC(Low-Side DC/DC Converter).
an input providing an input voltage;
a buck converter unit for step-down the input voltage to lower the voltage;
a DC/DC converter for stepping down the lowered voltage and electrically insulating from the buck converter; and
an output unit for outputting the voltage step-down from the DC/DC converter unit; is connected in order and included;
A low-side DC/DC converter (LDC) having a two-stage structure for an electric vehicle, characterized in that it includes; a control unit for controlling the switching of the buck converter unit and the DC/DC converter unit.
 제1항에 있어서,
상기 DC/DC 컨버터부는 PSFB(Phase Shift Full-Bridge) 컨버터인 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC.
According to claim 1,
The DC/DC converter unit is a PSFB (Phase Shift Full-Bridge) converter, characterized in that the two-stage structure LDC for an electric vehicle.
 제1항에 있어서,
상기 DC/DC 컨버터부는 LLC(Inductor-Inductor-Capacitor) 공진 컨버터인 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC.
According to claim 1,
The DC/DC converter unit is an inductor-inductor-capacitor (LLC) resonant converter, characterized in that the two-stage structure LDC for an electric vehicle.
 제1항에 있어서,
상기 제어부는 상기 벅 컨버터부를 제어하기 위한 제1 제어부와 상기 DC/DC 컨버터부를 제어하기 위한 제2 제어부로 구성되는 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC.
According to claim 1,
Wherein the control unit comprises a first control unit for controlling the buck converter unit and a second control unit for controlling the DC/DC converter unit, LDC having a two-stage structure for an electric vehicle.
 입력 전압을 제공하는 입력부;
상기 입력 전압을 강압하여 낮추고 상기 입력부와 전기적으로 절연시키는 LLC 컨버터부;
상기 LLC 컨버터부에서 강압된 전압을 변환하는 벅(Buck) 컨버터부; 및
상기 벅 컨버터부에서 변환된 전압을 출력하는 출력부;가 순서대로 연결되어 포함되고,
상기 LLC 컨버터부와 벅 컨버터부의 스위칭을 제어하는 제어부;를 포함하는 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC(Low-Side DC/DC Converter).
an input providing an input voltage;
an LLC converter unit for step-down and lowering the input voltage and electrically insulates from the input unit;
a buck converter unit for converting the voltage step-down in the LLC converter unit; and
an output unit for outputting the voltage converted by the buck converter unit; is connected in order and included;
A low-side DC/DC converter (LDC) having a two-stage structure for an electric vehicle, characterized in that it includes; a control unit for controlling the switching of the LLC converter unit and the buck converter unit.
 제5항에 있어서,
상기 제어부는 상기 LLC 컨버터부를 제어하는 제1 제어부와 상기 벅 컨버터부를 제어하는 제2 제어부로 구성되는 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC.
6. The method of claim 5,
Wherein the control unit comprises a first control unit for controlling the LLC converter unit and a second control unit for controlling the buck converter unit, LDC having a two-stage structure for an electric vehicle.
 제6항에 있어서,
상기 LLC 컨버터부는 공진주파수로만 동작하여 입력전압에 비례하여 출력전압이 생성되는 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC.
7. The method of claim 6,
The LLC converter unit operates only at a resonant frequency so that an output voltage is generated in proportion to an input voltage.
 제5항에 있어서,
상기 제어부는 상기 LLC 컨버터부의 출력전압의 변화에 따라 벅 컨버터부의 스위칭 주파수를 제어하여 상기 출력부의 출력전압이 일정하도록 제어하는 것을 특징으로 하는, 전기자동차용 2단 구조의 LDC.6. The method of claim 5,
Wherein the control unit controls the switching frequency of the buck converter unit according to a change in the output voltage of the LLC converter unit to control the output voltage of the output unit to be constant.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102488223B1 (en) 2022-05-26 2023-01-16 지투파워(주) Charging system for electric vehicle with resonant dc-dc converter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102488223B1 (en) 2022-05-26 2023-01-16 지투파워(주) Charging system for electric vehicle with resonant dc-dc converter

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