Integrated direct-current output transformer, high-voltage direct-input direct-output direct-current charging pile and direct-current charging system

Abstract

This invention relates to the field of electric vehicle charging technology, specifically an integrated DC output transformer, a high-voltage direct-input DC charging pile, and a DC charging system. It includes an integrated DC output transformer with an integrated high-voltage active rectifier module, a high-voltage direct-input DC charging pile equipped with a DC input interface and an isolated bidirectional DC / DC converter, and a charging system formed by interconnecting the two via a DC bus. The transformer employs high-voltage side rectification and sensorless closed-loop control. The charging pile utilizes a resonant topology and wide-bandgap devices and features battery adaptive adjustment. The system is equipped with standardized docking modules. This invention significantly improves power conversion efficiency and charging power density, reduces transmission losses and equipment heat generation, simplifies installation and maintenance processes, enhances operational stability and battery compatibility, and ensures safe and reliable operation in high-power fast charging scenarios.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle charging technology, and is an integrated DC output transformer, a high-voltage direct-input and direct-output DC charging pile, and a DC charging system. Background Technology

[0002] Current DC charging equipment for electric vehicles generally adopts a low-voltage rectification and multi-stage conversion architecture, which first steps down the high-voltage AC power before rectification. This results in numerous conversion stages and significant energy losses, making it difficult to meet the high-efficiency operation requirements of high-power fast charging. Traditional charging transformers and rectifier units are separate, leading to complex installation and wiring, large space requirements, long on-site construction periods, and a lack of dedicated high-efficiency rectifier topologies on the high-voltage side. This results in weak current ripple control, making it susceptible to impacts on downstream equipment and insufficient long-term operational stability. Existing charging piles mostly use conventional silicon-based power devices and ordinary conversion topologies, which result in high switching losses and severe heat generation under high-frequency operation, limiting power density improvement and making them unsuitable for the direct-in / direct-out charging requirements of high-voltage platform vehicles.

[0003] Existing charging equipment employs a relatively simple control strategy, executing the charging process only according to fixed parameters. It cannot adjust the output voltage slope and current rate in real time based on the remaining charge and temperature status of the power battery, easily causing battery polarization losses and affecting battery lifespan. Furthermore, it suffers from poor compatibility with different brands and voltage platforms, lacking versatility. The internal component connections of the charging system are inconsistent, lacking standardized interface structures, making later maintenance and replacement difficult and resulting in high operation and maintenance costs, hindering the large-scale deployment and efficient management of charging stations.

[0004] Traditional DC charging systems suffer from low overall conversion efficiency, with significant voltage drop and heat generation issues in the high-voltage DC transmission circuit. Prolonged high-power operation can lead to overheating and unstable output, increasing operating energy costs and posing safety hazards. Existing equipment fails to establish an integrated, efficient link connecting high-voltage AC input, high-voltage DC direct transmission, and battery-compatible output. Its overall architecture suffers from high redundancy and low integration, failing to meet the multiple demands of high efficiency, stability, intelligence, and convenience, and thus ill-suited to the development trend of high-voltage fast charging for new energy vehicles. Summary of the Invention

[0005] This invention provides an integrated DC output transformer, a high-voltage direct-input DC charging pile, and a DC charging system, which overcomes the shortcomings of the prior art and can effectively solve the problems of multiple conversion links, high losses, and low power density in traditional charging equipment.

[0006] One of the technical solutions of this invention is achieved through the following measures: an integrated DC output transformer, comprising a transformer body and a high-voltage active rectifier module; the transformer body is used to transform the input high-voltage AC power, and the high-voltage active rectifier module is used to convert the transformed AC power into high-voltage DC power; the input terminal of the transformer body is electrically connected to the high-voltage AC power supply, the output terminal of the transformer body is electrically connected to the input terminal of the high-voltage active rectifier module, and the output terminal of the high-voltage active rectifier module is connected to the DC bus.

[0007] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The aforementioned high-voltage active rectifier module can be integrated into the end of the core winding of the transformer body.

[0008] The aforementioned high-voltage active rectifier module can adopt a PWM rectifier topology or a cascaded H-bridge rectifier topology to achieve efficient AC to DC conversion on the high-voltage side.

[0009] The aforementioned high-voltage active rectifier module can have a built-in sensorless current closed-loop control unit for real-time adjustment of the ripple coefficient of the rectified output current.

[0010] The second technical solution of the present invention is achieved through the following measures: a high-voltage direct-input direct-output DC charging pile, comprising a DC input interface and an isolated bidirectional DC / DC converter; the DC input interface is used to connect to high-voltage DC power, and the isolated bidirectional DC / DC converter is used to step down the high-voltage DC power to a charging DC power suitable for the power battery; the input end of the DC input interface is electrically connected to an external high-voltage DC power supply, the output end of the DC input interface is electrically connected to the input end of the isolated bidirectional DC / DC converter, and the output end of the isolated bidirectional DC / DC converter is connected to the electric vehicle power battery.

[0011] The following are further optimizations and / or improvements to the second technical solution of the above invention: The aforementioned charging pile can be equipped with a multi-mode adaptive control unit, which can automatically adjust the output voltage slope and charging current rate of the DC / DC converter according to the remaining power and temperature status of the electric vehicle's power battery.

[0012] The aforementioned isolated bidirectional DC / DC converter can employ an LLC resonant topology to achieve efficient isolated DC-DC buck conversion and reduce switching losses.

[0013] The aforementioned isolated bidirectional DC / DC converter can use silicon carbide MOSFET devices to improve high-frequency operating efficiency and reduce device size and heat generation.

[0014] The third technical solution of the present invention is achieved through the following measures: a high-voltage direct-input direct-output DC charging system, comprising an integrated DC output transformer and a high-voltage direct-input direct-output DC charging pile; wherein, the integrated DC output transformer is the aforementioned integrated DC output transformer, used to convert high-voltage AC power into high-voltage DC power and output it to the DC bus; wherein, the high-voltage direct-input direct-output DC charging pile is the aforementioned high-voltage direct-input direct-output DC charging pile, used to convert the high-voltage DC power from the DC bus into charging DC power adapted to the power battery; the output end of the integrated DC output transformer is electrically connected to the DC bus, the DC bus is electrically connected to the DC input interface of the high-voltage direct-input direct-output DC charging pile, and the charging output end of the high-voltage direct-input direct-output DC charging pile is connected to the electric vehicle power battery.

[0015] The following are further optimizations and / or improvements to the third technical solution of the above invention: The aforementioned DC charging system may also include a docking module, through which the integrated DC output transformer and the charging pile can achieve standard modular docking.

[0016] This invention simplifies the charging system architecture through integrated design, reduces energy conversion stages, effectively lowers transmission and conversion losses, and improves overall power utilization efficiency. A dedicated high-voltage side rectifier topology and closed-loop control unit stabilize the output current, reduce ripple interference, and ensure continuous and reliable system operation. The charging pile employs a novel topology and wide bandgap devices, significantly reducing switching losses and heat generation, improving power density and operational stability, and adapting to the fast-charging requirements of high-voltage platforms. Multi-mode adaptive control accurately matches battery status, optimizes charging parameters, reduces battery damage, extends battery life, and enhances compatibility with different vehicle models. Standardized interface modules enable rapid component assembly and interconnection, simplifying on-site construction and subsequent maintenance processes, reducing operation and maintenance costs, and facilitating large-scale deployment. The overall system boasts high integration, a compact structure, and high efficiency, combining stability, intelligence, and convenience, fully meeting the needs of high-power high-voltage DC charging for electric vehicles. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the integrated DC output transformer according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of a high-voltage direct-input direct-output DC charging pile according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the overall structure of a high-voltage direct-input direct-output DC charging system according to an embodiment of the present invention. Detailed Implementation

[0020] The present invention is not limited to the following embodiments, and specific implementation methods can be determined according to the present invention and actual conditions.

[0021] The present invention will be further described below with reference to embodiments: Example 1: As Figure 1 As shown, this embodiment provides an integrated DC output transformer, including a transformer body and a high-voltage active rectifier module. The transformer body is used to transform the input high-voltage AC power, and the high-voltage active rectifier module is used to convert the transformed AC power into high-voltage DC power. The input terminal of the transformer body is electrically connected to the high-voltage AC power supply, and the output terminal of the transformer body is electrically connected to the input terminal of the high-voltage active rectifier module. The output terminal of the high-voltage active rectifier module is connected to the DC bus, which can directly convert high-voltage AC power into stable high-voltage DC power, reduce intermediate step-down stages, and improve conversion efficiency.

[0022] In this embodiment, the high-voltage active rectifier module is integrated into the end of the core winding of the transformer body, which can reduce the size of the equipment, increase the integration, reduce wiring losses, and enhance structural stability.

[0023] In this embodiment, the high-voltage active rectifier module adopts a PWM rectifier topology or a cascaded H-bridge rectifier topology to achieve efficient AC to DC conversion on the high-voltage side. This can adapt to high-voltage working environments and improve rectification efficiency and output accuracy.

[0024] In this embodiment, the high-voltage active rectifier module has a built-in sensorless current closed-loop control unit, which is used to adjust the ripple coefficient of the rectified output current in real time. This can stabilize the current without adding sampling devices and reduce the impact of ripple on downstream equipment.

[0025] During operation, after the integrated DC output transformer is connected to the public grid high-voltage AC power, the transformer body first completes the voltage transformation. At the end of the iron core winding, the high-voltage AC signal is directly sent to the integrated high-voltage active rectifier module. The high-voltage side AC-DC conversion is realized through PWM rectification topology or cascaded H-bridge topology. At the same time, the sensorless current closed-loop control unit adjusts the output current ripple in real time, and continuously delivers stable high-voltage DC power to the DC bus. The energy conversion is completed under high-voltage and low-current conditions throughout the entire process, without going through low-voltage step-down and low-voltage rectification stages.

[0026] The integrated DC output transformer uses 10kV public grid high-voltage AC power as input. Leveraging the electrical characteristics of high voltage and low current, it effectively reduces copper losses, iron losses, and switching losses during transmission, avoiding the significant energy losses caused by low-voltage, high-current rectification at the source. The integrated DC output transformer can employ a combination structure of a medium-frequency transformer and a cascaded H-bridge rectifier, with a rated conversion efficiency of no less than 98.5%. It can be cooled by oil immersion or air cooling, meeting the requirements for long-term stable outdoor installation and operation. By fully utilizing the physical characteristics of high voltage and low current, it significantly reduces copper losses, iron losses, and switching losses, resulting in a smooth and shock-free current output. The module integration at the winding end makes the structure more compact. Supporting both oil immersion and air cooling, it has strong adaptability to outdoor installation, eliminating the high-loss problems of traditional low-voltage rectification at the source.

[0027] Example 2: Figure 2 As shown, this embodiment provides a high-voltage direct-input direct-output DC charging pile, including a DC input interface and an isolated bidirectional DC / DC converter. The DC input interface is used to connect to high-voltage DC power, and the isolated bidirectional DC / DC converter is used to step down the high-voltage DC power to a charging DC power suitable for the power battery. The input end of the DC input interface is electrically connected to an external high-voltage DC power supply, and the output end of the DC input interface is electrically connected to the input end of the isolated bidirectional DC / DC converter. The output end of the isolated bidirectional DC / DC converter is connected to the electric vehicle power battery, which can directly connect to high-voltage DC and complete isolation and voltage reduction to meet battery charging needs.

[0028] In this embodiment, the charging pile has a built-in multi-mode adaptive control unit, which automatically adjusts the output voltage slope and charging current rate of the DC / DC converter according to the remaining power and temperature status of the electric vehicle's power battery. This can intelligently match the battery status, optimize the charging process, and protect the battery life.

[0029] In this embodiment, the isolated bidirectional DC / DC converter adopts an LLC resonant topology to achieve efficient isolated DC-DC buck conversion and reduce switching losses, thereby improving conversion efficiency, reducing device heat generation, and supporting high-frequency operation.

[0030] In this embodiment, the isolated bidirectional DC / DC converter uses silicon carbide MOSFET devices to improve high-frequency operating efficiency and reduce device size and heat generation, which can further improve power density and enhance equipment reliability.

[0031] During operation, the high-voltage direct-input direct-output DC charging pile directly obtains high-voltage DC power from the DC bus through the DC input interface. Internally, it eliminates the need for a rectifier bridge and PFC circuit, and only uses an isolated bidirectional DC / DC converter with LLC resonant topology to perform isolated voltage reduction. It also uses silicon carbide MOSFET devices to improve high-frequency performance. At the same time, a multi-mode adaptive control unit collects the remaining power and temperature information of the power battery in real time, and automatically adjusts the output voltage slope and charging current rate to accurately convert the high-voltage DC into charging energy adapted to the battery and output it to the vehicle.

[0032] High-voltage direct-input DC charging piles eliminate the traditional rectifier bridge and PFC circuit, resulting in a minimalist overall structure. Their size is reduced by more than 65% compared to traditional charging piles of the same power, significantly reducing equipment weight and allowing for more flexible installation and layout. These charging piles support a wide voltage range of 200V to 1000V, with a maximum output power of 480kW to 600kW. They are perfectly compatible with 400V and 800V high-voltage power batteries, achieving ultra-fast charging in as little as 10 minutes. Utilizing a pure DC-DC architecture, these charging piles offer a significantly faster response time than traditional AC-DC charging piles, allowing for more precise charging output adjustment and better matching of power battery charging characteristics, thus extending battery life.

[0033] Example 3: As Figure 3 As shown, this embodiment provides a high-voltage direct-input direct-output DC charging system, including an integrated DC output transformer and a high-voltage direct-input direct-output DC charging pile. The integrated DC output transformer is the aforementioned integrated DC output transformer, used to convert high-voltage AC power into high-voltage DC power and output it to the DC bus. The high-voltage direct-input direct-output DC charging pile is the aforementioned high-voltage direct-input direct-output DC charging pile, used to convert the high-voltage DC power from the DC bus into charging DC power adapted to the power battery. The output terminal of the integrated DC output transformer is electrically connected to the DC bus, the DC bus is electrically connected to the DC input interface of the high-voltage direct-input direct-output DC charging pile, and the charging output terminal of the high-voltage direct-input direct-output DC charging pile is connected to the electric vehicle's power battery, forming a complete high-voltage direct-input direct-output charging link, improving the overall system efficiency and stability.

[0034] In this embodiment, the DC charging system also includes a docking module. The integrated DC output transformer and the charging pile are docked in a standardized modular manner through the docking module, which enables rapid assembly and standardized interconnection, reducing the difficulty of installation and maintenance.

[0035] During operation, the integrated high-voltage AC input DC output transformer transforms and rectifies the voltage to output stable high-voltage DC power to the DC bus. The charging pile obtains high-voltage DC power through the DC input interface, which is then stepped down and adapted by an isolated bidirectional DC / DC converter to charge the electric vehicle's power battery. The control unit adjusts the charging parameters in real time according to the battery status. All components of the system are stably connected through standardized docking modules, achieving efficient, stable, and intelligent high-voltage DC fast charging, effectively reducing losses, simplifying deployment, and extending the lifespan of equipment and batteries.

[0036] The integrated DC output transformer is directly connected to the high-voltage direct-in / direct-out DC charging pile via a DC bus, eliminating the need for AC distribution panels, low-voltage AC cabinets, and traditional rectifier cabinets. This reduces the overall footprint of the charging station by 40% to 50%. The overall system conversion efficiency is 3% to 8% higher than traditional charging equipment, resulting in significant long-term energy savings. Furthermore, the larger the transformer's rated capacity, the more pronounced the energy efficiency advantage of the high-voltage side rectification, making it more suitable for large-scale deployment of centralized charging stations. The entire charging process involves only one AC-DC conversion on the high-voltage side of the integrated DC output transformer. The charging pile itself only performs a DC-DC step-down operation, without any additional AC rectification stages. This reduces system failure points by more than 50%, significantly improving equipment reliability and reducing subsequent maintenance costs. The high-voltage direct-input direct-output DC charging system uses an integrated DC output transformer as the front stage to directly convert 10kV high-voltage AC to high-voltage DC and transmit it to the DC bus. The subsequent high-voltage direct-input direct-output DC charging pile completes the step-down charging. The two are connected quickly by a standard modular docking structure. The system retains only one high-voltage AC-DC conversion and one DC-DC step-down conversion throughout the entire process, completely eliminating redundant links such as traditional low-voltage rectification and low-voltage AC power distribution. It forms a complete and efficient link of high-voltage direct input, DC direct transmission, and DC direct charging. The charging speed and operational stability are significantly improved. The larger the capacity, the more obvious the energy efficiency advantage. It is especially suitable for large-scale deployment of centralized charging stations.

[0037] It should be noted that in this invention, the high-voltage active rectifier module refers to an active power conversion module that operates on the high-voltage side and converts AC power to DC power; the sensorless current closed-loop control unit refers to a control circuit that can achieve closed-loop regulation of the output current without relying on additional current sampling devices; the LLC resonant topology refers to a resonant DC-DC conversion topology composed of inductors, capacitors, and inductors; the silicon carbide MOSFET device refers to a metal-oxide-semiconductor field-effect transistor made of silicon carbide; the multi-mode adaptive control unit refers to a control module that can automatically switch charging strategies according to battery status; and the standard modular docking refers to a connection method with unified mechanical and electrical interfaces that allows for rapid assembly. The integrated DC output transformer has a rated input of 10kV, 50Hz high-voltage AC power and a rated output of 10kV or 15kV high-voltage DC power, with a rated conversion efficiency of not less than 98.5%. It can be cooled by oil immersion or air cooling. The high-voltage active rectifier module adopts PWM rectification or cascaded H-bridge topology, and the matching sensorless current closed-loop control unit controls the output current ripple coefficient at a low level, ensuring stable and reliable rectification on the high-voltage side. The high-voltage direct-input DC charging pile features a DC input interface compatible with 10kV high-voltage DC input. Its internal isolated bidirectional DC / DC converter employs an LLC resonant topology, and the switching devices utilize silicon carbide MOSFETs with a rated withstand voltage of at least 10kV. The output voltage covers a wide range from 200V to 1000V, with a rated output power of 480kW to 600kW. A multi-mode adaptive control unit can collect battery power and temperature signals in real time and dynamically adjust the output voltage slope and charging current, making it compatible with charging requirements for power batteries across various voltage platforms, including 400V and 800V. The high-voltage direct-input DC charging system adopts a direct-connection DC bus architecture. The DC bus has a rated withstand voltage of at least 15kV, and its current carrying capacity meets the requirements of high-power fast charging. The integrated DC output transformer and charging pile achieve rapid mechanical and electrical connection through a standard modular docking module, with a protection level suitable for outdoor use.

[0038] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. An integrated DC output transformer, characterized in that, This includes the transformer body and the high-voltage active rectifier module; The transformer body is used to transform the voltage of the input high-voltage AC power, and the high-voltage active rectifier module is used to convert the transformed AC power into high-voltage DC power. The input terminal of the transformer body is electrically connected to the high-voltage AC power supply, the output terminal of the transformer body is electrically connected to the input terminal of the high-voltage active rectifier module, and the output terminal of the high-voltage active rectifier module is connected to the DC bus.

2. The integrated DC output transformer according to claim 1, characterized in that, The high-voltage active rectifier module is integrated at the end of the core winding of the transformer body.

3. The integrated DC output transformer according to claim 1 or 2, characterized in that, The high-voltage active rectifier module adopts a PWM rectifier topology or a cascaded H-bridge rectifier topology to achieve efficient AC to DC conversion on the high-voltage side.

4. The integrated DC output transformer according to claim 1 or 2, characterized in that, The high-voltage active rectifier module has a built-in sensorless current closed-loop control unit for real-time adjustment of the ripple coefficient of the rectified output current.

5. A high-voltage direct-input direct-output DC charging pile, characterized in that, Includes a DC input interface and an isolated bidirectional DC / DC converter; The DC input interface is used to connect to high-voltage DC power, and the isolated bidirectional DC / DC converter is used to step down the high-voltage DC power to a charging DC power suitable for the power battery; The input terminal of the DC input interface is electrically connected to an external high-voltage DC power supply, and the output terminal of the DC input interface is electrically connected to the input terminal of the isolated bidirectional DC / DC converter. The output terminal of the isolated bidirectional DC / DC converter is connected to the electric vehicle's power battery.

6. The high-voltage direct-input direct-output DC charging pile according to claim 5, characterized in that, The charging pile has a built-in multi-mode adaptive control unit, which automatically adjusts the output voltage slope and charging current rate of the DC / DC converter according to the remaining power and temperature status of the electric vehicle's power battery.

7. The high-voltage direct-input direct-output DC charging pile according to claim 5 or 6, characterized in that, The isolated bidirectional DC / DC converter uses an LLC resonant topology to achieve efficient isolated DC-DC buck conversion and reduce switching losses.

8. The high-voltage direct-input direct-output DC charging pile according to claim 5 or 6, characterized in that, Isolated bidirectional DC / DC converters use silicon carbide MOSFET devices to improve high-frequency operating efficiency and reduce device size and heat generation.

9. A high-voltage direct-input direct-output DC charging system, characterized in that, Includes an integrated DC output transformer and a high-voltage direct-input DC charging pile; The integrated DC output transformer is the integrated DC output transformer according to any one of claims 1 to 4, used to convert high-voltage AC power into high-voltage DC power and output it to the DC bus. Among them, the high-voltage direct-input direct-output DC charging pile is the high-voltage direct-input direct-output DC charging pile as described in any one of claims 5 to 8, which is used to convert the high-voltage DC power of the DC bus into charging DC power adapted to the power battery. The output end of the integrated DC output transformer is electrically connected to the DC bus, the DC bus is electrically connected to the DC input interface of the high-voltage direct-input DC charging pile, and the charging output end of the high-voltage direct-input DC charging pile is connected to the power battery of the electric vehicle.

10. The DC charging system according to claim 9, characterized in that, It also includes a docking module, through which the integrated DC output transformer and the charging pile can achieve standard modular docking.

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