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DCFC 集成了多种器件，包括用于辅助电源、感测、电源管理、连接和通信的器件。另外，为了满足各种电动汽车不断发展的充电需求，必须采用灵活的制造方法，这也使设计变得更加复杂。
DCFC integrates a variety of devices, including those for auxiliary power, sensing, power management, connectivity and communication. In addition, in order to meet the evolving charging needs of various electric vehicles, flexible manufacturing methods must be adopted, which also makes the design more complicated.
充电时间是消费者和企业评估购买电动汽车 (EV)的一个主要考虑因素。为了缩短充电时间，业界正转向采用直流充电桩 (DCFC) 。DCFC 绕过电动汽车的车载充电器，直接向电池提供更高的功率，从而大大缩短充电时间。
Charging time is a major consideration for consumers and businesses evaluating the purchase of an electric vehicle (EV). In order to reduce charging times, the industry is turning to direct current charging piles (DCFC). The DCFC bypasses electric vehicles' on-board chargers and delivers higher power directly to the battery, greatly reducing the charging time.
为了实现更快的充电速度、适配更高的电动汽车电池电压并提高整体能效，DCFC 必须在更高的电压和功率水平下运行。这给 OEM 带来了挑战，必须设计出一种能够优化效率，同时不影响可靠性和安全性的架构。
To achieve faster charging speeds, adapt to higher EV battery voltages, and improve overall energy efficiency, DCFC must operate at higher voltage and power levels. This presents Oems with the challenge of designing an architecture that optimizes efficiency without compromising reliability and security.
DCFC 集成了多种器件，包括用于辅助电源、感测、电源管理、连接和通信的器件。另外，为了满足各种电动汽车不断发展的充电需求，必须采用灵活的制造方法，这也使设计变得更加复杂。
DCFC integrates a variety of devices, including those for auxiliary power, sensing, power management, connectivity and communication. In addition, in order to meet the evolving charging needs of various electric vehicles, flexible manufacturing methods must be adopted, which also makes the design more complicated.
图 1. DCFC 中的主要模块概览
Figure 1. Overview of the major modules in DCFC
快速和超快速充电
Fast and ultra-fast charging
图 2 显示了交流充电和直流充电之间的差异。对于交流充电（图 2 左侧），车载充电器 (OBC) 插入标准交流插座。OBC 将交流电转换为适当的直流电为电池充电。对于直流充电（图 2 右侧），充电桩直接给电池充电。
Figure 2 shows the difference between AC charging and DC charging. For AC charging (Figure 2, left), the on-board charger (OBC) plugs into a standard AC outlet. The OBC converts alternating current into appropriate direct current to charge the battery. For DC charging (right side of Figure 2), the charging pile directly charges the battery.
图 2.交流充电和直流充电概念图
Figure 2. Concept diagram of AC charging and DC charging
目前电动汽车的 OBC 依赖交流充电，最大额定功率为 22 kW。直流充电绕过了 OBC，直接向电池输送直流电，因此能提供高得多的功率，从 50 kW 到 400 kW 以上甚至更高。
The current OBC of electric vehicles relies on AC charging and has a maximum rated power of 22 kW. Dc charging bypasses the OBC and delivers direct current to the battery, thus providing much higher power, from 50 kW to more than 400 kW and beyond.
由于这个原因，DCFC 常被称为“快速”或“超快速”充电桩。如此高的充电速度和更大的便利性为电动汽车带来了更多的应用和用例。例如，电动汽车如果需要八小时才能充满电，是不适合长途驾驶的，但借助超快速充电桩，电动汽车可以在短暂的休息时间内大量充电，增加车辆的续航里程，使其更加适合日常使用。因此，从现在到 2030 年，快速直流充电桩的复合年增长率预计将超过 30%（来源：Yolé Development）。
For this reason, DCFC is often referred to as a "fast" or "super fast" charging pile. Such high charging speeds and greater convenience lead to more applications and use cases for electric vehicles. For example, an electric car is not suitable for long-distance driving if it takes eight hours to fully charge, but with the help of ultra-fast charging piles, electric cars can be charged in large quantities during short breaks, increasing the vehicle's range and making it more suitable for daily use. As a result, the compound annual growth rate of fast DC charging piles is expected to exceed 30% between now and 2030 (Source: Yole Development).
碳化硅 (SiC) 和功率集成模块 (PIM) 技术的进步，是促进向更快速充电转变的关键驱动力。SiC 使 DCFC 能够以更高的频率运行（因而效率也更高），同时以更快的速度提供更多功率。PIM 使 OEM 能够快速将先进的技术集成到紧凑、轻便的设备中，并实现出色的热管理、可靠性和可制造性，从而加快 SiC 技术的普及。
Advances in silicon carbide (SiC) and power integrated module (PIM) technology are key drivers in facilitating the shift to faster charging. SiC enables DCFC to operate at higher frequencies (and therefore more efficiently) while delivering more power at faster speeds. PIM enables Oems to quickly integrate advanced technologies into compact, lightweight devices and achieve excellent thermal management, reliability and manufacturability, accelerating the adoption of SiC technology.
DCFC 剖析
DCFC profiling
如图 3 所示，直流充电桩主要包括两级：AC-DC 级和后续 DC-DC 级。AC-DC 级将来自电网的交流电转换为直流电，而第二级确保以适合电池所需的电压和电流水平提供功率。
As shown in Figure 3, DC charging piles mainly include two levels: AC-DC level and subsequent DC-DC level. The AC-DC stage converts alternating current from the grid to direct current, while the second stage ensures that power is delivered at a level of voltage and current suitable for the battery's needs.
图 3. DCFC 的架构
Figure 3. Architecture of DCFC
对于商业应用，3 级充电桩需要使用三相电源（图 4），可以在短短 30 分钟内增加 100 多英里的续航里程。在将电动汽车技术引入运输和物流等应用方面，这些超快速充电桩将发挥重要作用。
For commercial applications, Level 3 charging piles require the use of three-phase power (Figure 4), which can add more than 100 miles of range in just 30 minutes. These ultra-fast charging points will play an important role in bringing electric vehicle technology to applications such as transport and logistics.
图 4. 单相电网的功率流（左），三相电网的功率流（右）
Figure 4. Power flow of single-phase network (left), power flow of three-phase network (right)
图 5. 快速直流充电桩的架构
Figure 5. Architecture of fast DC charging pile
3 级 DCFC 的前端由三相功率因数校正 (PFC) 升压级组成，可以是单向或双向；升压级可以采用各种拓扑（二电平或三电平）实现。PFC 级接受电网电压（400 EU、480 US），并将其升压至 700 至 1000 V。对于下一代充电桩，业界已经瞄准了更高电压。
The front end of a 3-stage DCFC consists of a three-phase power factor correction (PFC) boost stage, which can be unidirectional or bidirectional; The boost level can be implemented in a variety of topologies (two-level or three-level). The PFC stage accepts the grid voltage (400 EU, 480 US) and boosts it to 700 to 1000 V. For the next generation of charging piles, the industry has aimed at higher voltages.
在升压级之后，DC−DC 隔离级将总线电压转换为所需的输出电压。此电压需要与电动汽车电池的充电曲线保持一致。因此，DC-DC 输出可能需要在 150 V 至 1500 V 之间摆动，具体电压取决于电池和所处的充电阶段。转换器通常针对特定电压水平（常见为 400 V 或 800 V）进行优化。为了实现更高的功率水平，DCFC 会将多个功率模块（图 6）堆叠起来并联运行。
After the boost stage, the DC-DC isolation stage converts the bus voltage to the desired output voltage. This voltage needs to be consistent with the charging curve of electric vehicle batteries. Therefore, the DC-DC output may need to swing between 150 V and 1500 V, depending on the battery and the charging stage. Converters are typically optimized for a specific voltage level (typically 400 V or 800 V). To achieve higher power levels, DCFC stacks multiple power modules (Figure 6) to operate in parallel.
为了在此类高电压下实现更高的效率，业界正从分立式、IGBT 和混合方案转向 SiC 功率集成模块 (PIM)。（图 7）除 PIM 之外，DCFC 还需要多种功率器件，包括栅极驱动器 IC、数字隔离器、电源 IC（LDO、SMPS 等）和电流检测。
To achieve greater efficiency at these high voltages, the industry is moving from discrete, IGBT and hybrid solutions to SiC power integrated modules (PIMs). In addition to PIM, DCFC requires a variety of power devices, including gate driver ics, digital isolators, power ics (LDO, SMPS, etc.), and current detection.
图 6. 300 kW DCFC 中的 12 x 25 kW 构建模块
Figure 6. 12 x 25 kW building blocks in a 300 kW DCFC
图 7. 机电设计比较
Figure 7. Electromechanical design comparison
通信和连接也是 DCFC 设计的关键方面。堆叠的模块需要能够与充电桩控制器通信，车辆和充电桩必须就充电序列进行通信（CAN 或 PLC）。独立的快速直流充电桩还需要能够处理充电相关的支付。最后，充电桩需要管理自身的维护、软件升级等（例如通过蓝牙低功耗、Wi-Fi 4、LTE）。实际标准由所使用的直流充电协议规定，例如 IEC−61851 / SAE1772、GB/T、CHAdeMO、组合充电系统 (CCS) 或特斯拉超级充电桩（图 8）。
Communication and connectivity are also key aspects of DCFC design. The stacked modules need to be able to communicate with the charging pile controller, and the vehicle and charging pile must communicate about the charging sequence (CAN or PLC). Separate fast DC charging piles also need to be able to handle charging related payments. Finally, charging piles need to manage their own maintenance, software upgrades, etc. (e.g., via Bluetooth low power, Wi-Fi 4, LTE). The actual standard is specified by the DC charging protocol used, such as IEC−61851 / SAE1772, GB/T, CHAdeMO, Combined Charging System (CCS), or Tesla Supercharging Pile (Figure 8).
图 8. 交流和直流快速充电桩的架构
Figure 8. Architecture of AC and DC fast charging pile
DCFC 关键设计考虑因素
DCFC Key design considerations
设计 DCFC 时，有多个关键因素需要考虑，这些因素会影响架构设计和器件选择：
When designing DCFC, there are a number of key factors to consider, which affect architecture design and device selection:
目标效率：
Target efficiency:
确定应优化效率的电压和功率范围。充电桩在充电期间在不同的电平运行，因此系统应针对对电力传输效率影响最大的电平进行优化。
Determine the voltage and power ranges where efficiency should be optimized. The charging pile operates at different levels during charging, so the system should be optimized for the level that has the greatest impact on the efficiency of power transmission.
分立式设计还是功率集成模块 (PIM)：
Separate design or Power Integrated Module (PIM) :
分立式设计的灵活性更大，但开发过程也更复杂（图 7）。对于许多应用而言，模块在效率方面的诸多优势是分立式设计难以企及的。例如，模块将多个功率器件集成在单个紧凑的封装中，简化了机械组装，优化了热管理，提高了可靠性，并减少了电压尖峰和高频 EMI。
Separate designs offer more flexibility, but the development process is also more complex (Figure 7). For many applications, the efficiency benefits of modules are unmatched by discrete designs. For example, modules integrate multiple power devices in a single compact package, simplifying mechanical assembly, optimizing thermal management, improving reliability, and reducing voltage spikes and high-frequency EMI.
架构/拓扑结构：
Architecture/Topology:
所选择的拓扑结构（即二电平还是三电平）以及充电桩需要单向运行还是双向运行，都会影响器件的选择。实现直流充电桩 PFC 和 DC-DC 级的拓扑结构选项有许多。由于功率和电压水平非常高，许多 OEM 的首选架构一般是三级功率因数校正 (PFC)。PFC 设计最常用的拓扑结构有三开关 Vienna（单向）、NPC、A-NPC、T-NPC（双向替换二极管）和六开关（双向） 。DC−DC 级通常以全桥或相移 LLC 及其变体实现，并采用双有源桥 (DAB) 架构支持双向拓扑结构。这些拓扑结构包括二电平和三电平系统，它们分别采用 600 至 650 V 或 900 至 1200 V 开关和二极管。
The topology chosen (i.e., two-level or three-level) and whether the charging pile needs to operate in one direction or in two directions will affect the choice of devices. There are many topological options for implementing the PFC and DC-DC levels of DC charging piles. Due to the very high power and voltage levels, the preferred architecture for many Oems is generally three-stage power factor correction (PFC). The most commonly used topologies for PFC design are three-switch Vienna (one-way), NPC, A-NPC, T-NPC (two-way replacement diode), and six-switch (two-way). The DC-DC stage is typically implemented as a full bridge or phase-shifted LLC or its variants, and supports a bidirectional topology with a dual active bridge (DAB) architecture. These topologies include two - and three-level systems, which employ 600 to 650 V or 900 to 1200 V switches and diodes, respectively.
约束条件：
Constraints:
应注意物理系统约束，包括尺寸、重量、成本和其他需要考虑的限制因素。例如，如果尺寸和重量很重要，那么选择基于 SiC 的模块将能降低总体布线要求，减小系统尺寸，并减轻车重。
Pay attention to physical system constraints, including size, weight, cost, and other constraints that need to be considered. For example, if size and weight are important, choosing SIC-based modules will reduce overall wiring requirements, reduce system size, and reduce vehicle weight.
热管理：
Thermal Management:
管理散热对于维持效率、可靠性和系统使用寿命至关重要。使用 SiC 器件以更高频率运行，可以提高功率密度，提升效率，并减少需要管理的热量。此外，许多模块还针对使用极低热阻材料的热传递进行了优化。
Managing heat dissipation is critical to maintaining efficiency, reliability and system life. Using SiC devices to operate at higher frequencies increases power density, improves efficiency, and reduces the amount of heat that needs to be managed. In addition, many modules are optimized for heat transfer using extremely low thermal resistance materials.
仿真模型：
Simulation model:
拥有器件和模块的精确模型可以大大简化和加速设计过程，尤其是在权衡多种设计方案时。
Having accurate models of devices and modules can greatly simplify and speed up the design process, especially when weighing multiple design options.
通信：
Communication:
明确特定应用需要哪些标准和协议。确保所选的供应商和产品系列支持所有可能需要纳入的标准，以支持当今和未来的电动汽车。
Clarify what standards and protocols are required for a particular application. Ensure that the selected supplier and product family supports all the standards that may need to be incorporated to support today's and tomorrow's electric vehicles.
保护：
Protection:
根据法规要求，必须配备接地故障断路 (GFI) 功能。其他功能（如浪涌电流和过压保护）也至关重要。系统中如何集成这些功能（即单独的电路、功率级的一部分、集成在模块上等），将会影响对其他系统约束条件的优化。
A ground fault break (GFI) function is required by regulations. Other features, such as inrush current and overvoltage protection, are also critical. How these functions are integrated in the system (i.e. separate circuits, part of the power stage, integrated in modules, etc.) will affect the optimization of other system constraints.
先进的充电架构
Advanced charging architecture
理想情况下，电动汽车在非高峰时段充电。这会大大降低电力成本，并减少高峰时段电网的负荷，避免造成停电。
Ideally, electric cars are charged during off-peak hours. This will significantly reduce the cost of electricity and reduce the load on the grid during peak hours, avoiding blackouts.
为了实现这一目标，直流充电桩需要与储能系统 (ESS) 和太阳能发电系统集成。ESS 在非高峰时段充电，储存电力以供白天使用。通过安装太阳能电池板以在白天发电，可以减少对 ESS 电力的消耗，从而减轻 ESS 的负荷。在这种配置中，DC/DC 转换器可以连接到高压总线来为电动汽车充电。
To achieve this, DC charging piles need to be integrated with energy storage systems (ESS) and solar power generation systems. The ESS charges during off-peak hours, storing power for use during the day. By installing solar panels to generate electricity during the day, it is possible to reduce the consumption of ESS power, thereby reducing the load on the ESS. In this configuration, the DC/DC converter can be connected to a high-voltage bus to charge the electric vehicle.
图 9. 可再生太阳能电池板和储能设施供电的快速超级充电桩
Figure 9. Fast supercharging piles powered by renewable solar panels and energy storage facilities
安森美(onsemi)致力于在供应链的所有层面实现可持续发展。对于希望采用此类先进架构的 OEM，安森美可以帮助他们以高效、安全、可靠、可持续的方式集成合适的技术。
onsemi is committed to sustainability at all levels of the supply chain. For Oems looking to adopt such advanced architectures, On can help them integrate the right technologies in an efficient, safe, reliable and sustainable way.
快速和超快速直流充电是电动汽车的未来。快速直流充电桩能够将充电时间缩短至不到一小时，这将为电动汽车开辟一系列全新的应用领域和使用场景。
Fast and ultra-fast DC charging is the future of electric vehicles. The fast DC charging pile can reduce the charging time to less than one hour, which will open up a whole new range of application areas and use cases for electric vehicles.
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发表于 2024-8-5 13:34:17
