终端用户希望新的电动汽车设计能够最大限度地减少车辆的空闲时间，尤其是在长途驾驶中。电动汽车设计人员需要提高充电器的功率输出、功率密度和效率，以实现终端用户期望的快速充电。目前，单个单元充电器的设计范围是从7千瓦到30千瓦。将单个单元元件组合到模块化设计中可以增加功率输出，帮助充电器制造商实现占地面积更小、灵活性更高和可扩展性的目标。对有源功率元件使用先进的隔离封装，可实现更高的功率密度并显著减少电路设计中的热管理工作，从而解决大功率充电的挑战。
End users expect new electric vehicle designs to minimize idle time in the vehicle, especially on long drives. Electric vehicle designers need to improve the power output, power density and efficiency of chargers to achieve the fast charging that end users expect. At present, the design range of a single unit charger is from 7 kW to 30 kW. Combining individual unit elements into a modular design can increase power output, helping charger manufacturers achieve smaller footprint, greater flexibility, and scalability. The use of advanced isolated packaging for active power components solves the challenge of high-power charging by achieving higher power density and significantly reducing thermal management efforts in circuit design.
电力公司面临着额外的管理大负载的挑战，这些大负载是由增加的电动汽车使用的电动汽车电池充电而产生的。公用事业单位正在研究两项车辆到电网的技术：
Electric utilities face the additional challenge of managing the large loads that are created by charging the EV batteries used by the increased number of EVs. Utilities are working on two vehicle-to-grid technologies:
●V1G – 在这项称为智能充电的技术中，公用事业单位通过两种方式单独分配能量，以将需求峰值降至最低；即通过控制电动汽车开始充电的时间和供电的多少。
●V1G - In this technology, called smart charging, utilities distribute energy individually in two ways to minimize peak demand; That is, by controlling the time when the electric car starts charging and how much power is supplied.
●V2G – 双向充电控制充电时间、功率和方向。例如，为了减少峰值需求，该公用事业单位可以将充满电的电池中的一些电力拉回电网，然后将其供应给另一辆车。
●V2G - two-way charging controls charging time, power and direction. For example, to reduce peak demand, the utility could pull some of the power from a fully charged battery back into the grid and then supply it to another vehicle.
V2G方法对于车队来说可能非常具有成本效益，因为为调峰做出贡献将被认为是一项有价值的服务。例如，大多数校车只在白天运行，整晚都可以充电和共享电力。一支规模更大的车队，比如美国运营的50万辆校车，可以被控制成高度分散的能源储存。在美国暑假的100天空闲时间里，可用电池容量可以增长到GWh的水平。为了适应V2G技术，现在的设计人员需要开发双向充电器，这种充电器也可以为电网供电。
The V2G approach can be very cost effective for fleets, as contributing to peak load will be considered a valuable service. For example, most school buses only run during the day and can be charged and shared throughout the night. A much larger fleet, such as the 500,000 school buses operating in the United States, could be controlled into highly decentralized energy storage. During the 100 free days of the American summer vacation, the available battery capacity can grow to the level of GWh. To accommodate V2G technology, designers now need to develop two-way chargers that can also supply power to the grid.
与简单的单向充电器相比，双向充电器的设计更加复杂，需要更多的元件。还需要额外的努力来管理功耗和开发复杂的控制算法。
Compared with a simple one-way charger, the design of a two-way charger is more complex and requires more components. Additional effort is also required to manage power consumption and develop complex control algorithms.
处理更高功率需要高功率半导体的先进封装
Advanced packaging for high power semiconductors
图1显示了一种双向电源拓扑，该拓扑在8个半桥组中使用16个碳化硅功率MOSFET。为了实现更高的功率，电子设计人员可以并联使用更多的离散功率FET；然而，这会使电力电子系统的设计复杂化。分立功率FET封装通常为D²PAK或TO-247封装。当设计功率级别超过30 kW时，先进的隔离封装提供了支持所需高输出功率的元件。
Figure 1 shows a bidirectional power topology that uses 16 SIC power MOSFETs in eight half-bridge sets. To achieve higher power, electronic designers can use more discrete power FETs in parallel; However, this complicates the design of power electronic systems. Discrete power FET packages are typically in D²PAK or TO-247 packages. When design power levels exceed 30 kW, advanced isolated packages provide components to support the high output power required.
图1：具有多级功率转换的双向充电器电路
Figure 1: Two-way charger circuit with multistage power conversion
与分立封装不同，隔离封装允许将多个封装安装到一个公共散热器上。由于其外形小巧，与12毫米或17毫米功率模块相比，它们通过最小化子单元的总高度，提供了更紧凑的设计。此外，使用具有高绝缘强度的顶部冷却侧，器件和散热器之间不需要额外的隔离箔，使组装过程更容易，成本更低。
Unlike discrete packages, isolated packages allow multiple packages to be mounted on a common heat sink. Due to their compact size, they offer a more compact design by minimising the total height of the subunits compared to 12 mm or 17 mm power modules. In addition, with a top cooling side with high insulation strength, no additional isolation foil is required between the device and the radiator, making the assembly process easier and less costly.
图2显示了封装选项及其功率处理能力。这些封装选项根据输出功率和散热量以及印刷电路板(PCB)布局的复杂性和组装难度进行评级。表面贴装功率器件(SMPD)为设计人员提供了功率能力、功耗以及易于布局和组装的最佳组合。
Figure 2 shows the package options and their power handling capabilities. These package options are rated according to output power and heat dissipation, as well as the complexity and assembly difficulty of the printed circuit board (PCB) layout. Surface Mount Power Devices (SMPD) offer designers the best combination of power capability, power consumption, and ease of layout and assembly.
图2.封装功率能力与封装性能的比较
Figure 2. Comparison of package power capability and package performance
SMPD封装可实现更高功率密度
SMPD packages enable higher power density
电动汽车充电系统设计人员可以使用SMPD来容纳各种电压等级和电路拓扑（包括半桥）的各种芯片技术。SMPD封装的示例如图3所示。SMPD封装具有以下特点：
Ev charging system designers can use SMPD to accommodate a variety of chip technologies across a variety of voltage levels and circuit topologies, including half-bridges. An example of SMPD encapsulation is shown in Figure 3. SMPD packages have the following features:
●具有铜引线框架的直接铜键合 (DCB)基板，
●Direct Copper Bonding (DCB) substrate with copper lead frame,
●铝键合线，
● Aluminum bonding wire,
●半导体周围的塑料模塑化合物。
●Plastic molding compounds for semiconductors.
向后翻转金属翻盖，电池也会出现:
Flip the metal flap backwards and the battery will also appear:
DCB结构提供高隔离强度，从而实现了在单个载体上进行具有高散热能力的多半导体排列。DCB裸露的铜层最大限度地增加了散热器连接的可用表面积。铜引线框架与铝键合导线相结合，简化了焊接和组装。
The DCB structure provides high isolation strength, enabling multiple semiconductor arrangements with high heat dissipation on a single carrier. The exposed copper layer of the DCB maximizes the available surface area for the radiator connection. Copper lead frames are combined with aluminum bonding wires to simplify welding and assembly.
图 3. 表面贴装功率器件 (SMPD) 封装的示例结构
Figure 3. An example structure of a surface Mount power device (SMPD) package
本示例中的 SMPD 封装设计具有以下几个优点：
The SMPD package design in this example has several advantages:
●UL认证，额定绝缘电压高达2500 V
●UL certification, rated insulation voltage up to 2500 V
●与其它半导体封装（例如 TO 型器件）相比，热阻更低。
●Lower thermal resistance compared TO other semiconductor packages, such as TO-type devices.
●SMPD 提供比 TO 型封装更高的载流能力。
●SMPD offers higher current-carrying capacity than TO-type packages.
●最大限度地利用半导体的能力，以及由于封装的低杂散电感导致的低电压过冲。
●Maximize the capability of the semiconductor and the low voltage overshoot due to the low spurious inductance of the package.
●在启用定制拓扑方面具有更大的灵活性，包括晶闸管、功率二极管、MOSFET 和 IGBT。
●Greater flexibility in enabling custom topologies, including thyristors, power diodes, MOSFETs, and IGBTs.
●由于背面隔离，所有功率半导体都可以安装在单个散热器上。
●Due to back isolation, all power semiconductors can be mounted on a single radiator.
如图4所示，SMPD封装有两个版本，即SMPD-X和SMPD-B。SMPD-X包含单个开关、单个二极管或Co-Pack，可以在一个封装中满足更高的功率需求。SMPD-B允许在各种电压、电流和技术中构建模块，如各种拓扑中的MOSFET、IGBT和晶闸管。
As shown in Figure 4, there are two versions of the SMPD package, namely SMPD-X and SMPD-B. The SMPD-X contains a single switch, a single diode, or a Co-Pack to meet higher power requirements in a single package. SMPD-B allows building blocks in a variety of voltages, currents, and technologies, such as MOSFETs, IGBTs, and thyristors in various topologies.
图4：SMPD-X和SMPD-B封装比较
Figure 4: SMPD-X and SMPD-B package comparison
两个版本都具有相同的封装尺寸，长度为25 mm，宽度为23 mm，并且具有共同的占地面积和安装面积。
Both versions have the same package size, 25 mm in length and 23 mm in width, and have a common footprint and mounting area.
19英寸机架，具有两个高度单元(2HU)，长度为880 mm，用于电动汽车充电子单元，在行业中随处可见。例如，当使用薄型SMPD封装时，与采用19英寸2HU机架配置的E2和E3封装相比，该设计节省了约13%的体积，从而为功率磁件和去耦合电容器等无源元件提供了更大的空间。
The 19-inch rack, with two height units (2HU) and a length of 880 mm, is used for electric vehicle charging electronic units, which are ubiquitous in the industry. For example, when thin SMPD packages are used, the design saves about 13% of volume compared to E2 and E3 packages in 19-inch 2HU rack configurations, giving more room for passive components such as power magnetic parts and decoupling capacitors.
图5所示。减少所需的元件数量可实现更高的功率密度和更高的功率，并减小总体组装尺寸。图5所示的每个封装包含了两个功率MOSFET，这是SMPD封装的多个电路配置中的一个示例。
Figure 5 shows this. Reducing the number of components required allows for higher power density, higher power, and reduced overall assembly size. Each package shown in Figure 5 contains two power MOSFETs, an example of multiple circuit configurations for SMPD packages.
图5.基于SMPD封装的双向充电器将元件数量减少了将近50%
Figure 5. Two-way chargers based on SMPD packages reduce the number of components by nearly 50%
如果要求目标是更高的功率水平，SMPD还可用于IGBT和碳化硅MOSFET的单开关配置。一旦设计需要更高的电压，就可以随时选择1700V及以上的封装选项。
SMPD can also be used in single-switch configurations of IGBTs and silicon carbide MOSFETs if the requirement is for higher power levels. Once the design requires higher voltages, package options of 1700V and above can be selected at any time.
目标：更小的封装和更高的功率
The goal: smaller package and higher power
通过采用SMPD封装，设计人员可以提高电动汽车充电器的功率，从而提高功率密度和效率。SMPD使设计人员能够开发输出功率高达50 kW的单功率单元，而无需并联元件。使用SMPD功率元件有助于通过使用更少的元件来降低制造成本。表面贴装封装设计（如Littelfuse的设计），可以通过低热阻封装技术将散热器尺寸和成本降至最低。使用这种封装可以降低辐射和传导EMI，并具有较低的寄生电容和杂散电感。设计人员还可以通过在更高频率下工作来使用更小的电感器，从而进一步节省空间和成本。
By adopting SMPD packaging, designers can increase the power of electric vehicle chargers, thereby increasing power density and efficiency. SMPD enables designers to develop single power units with an output power of up to 50 kW without the need for parallel components. The use of SMPD power components helps reduce manufacturing costs by using fewer components. Surface mount package designs, such as Littelfuse's, minimize heat sink size and cost through low thermal resistance package technology. Using this package can reduce radiated and conducted EMI and has lower parasitic capacitance and stray inductance. Designers can also use smaller inductors by operating at higher frequencies, further saving space and costs.
一句话：SMPD功率器件封装使设计人员在不大幅增加系统尺寸和重量的情况下，增加了输出功率。
Bottom line: SMPD power device packages allow designers to increase output power without significantly increasing the size and weight of the system.
