Densely populated cities, limited traffic space and ambitious climate goals are driving the push for more sustainable transportation and mobility. In addition to emissions, factors like land use, noise pollution and quality of life are increasingly in focus.
Low-speed electric vehicles – also known as light electric vehicles (LEVs) – are considered a key technology in this context. They combine compact vehicle concepts with locally emission-free mobility. If LEVs were to gain a significant share of private and commercial transport, they could make a substantial contribution to climate protection. Due to their low weight and limited maximum speed, they consume considerably less energy during operation. The resource requirements for their production are also lower than those of high-voltage topologies.
Dynamic market for urban electric mobility
The market for LEVs offers strong global growth potential. Dynamic growth in distribution can be observed particularly in Asia, the ASEAN region, Latin America and Eastern Europe. Beyond private customers, LEVs are increasingly targeting urban commercial transport, for example for courier, express and parcel services or last-mile deliveries.
Current forecasts project the global LEV market to grow from USD 81.23 billion in 2022 to approximately USD 205.76 billion by 2032, reflecting an average annual growth rate of 9.74% over the forecast period. This growth is driven by advances in battery and drive technology, along with government incentives for sustainable mobility.
LEVs are easy to use, affordable and require minimal maintenance. This increases demand and creates enormous growth opportunities for market players. LEVs occupy less traffic and parking space than conventional cars and can be flexibly integrated into existing mobility and logistics concepts. These properties make them a sustainable solution for urban areas with limited space, for example for short commutes, errands and other daily activities.
48 V systems for LEVs
In the low-speed electric vehicle segment, 48 V electrical systems have become a widely adopted practical standard. They enable compact and cost-efficient implementation of electric drive and charging systems without the complexity of conventional high-voltage technology. This provides an ideal balance of performance, safety and energy efficiency – particularly for L7e-class vehicles and smaller.
For applications such as electric scooters, compact commercial vehicles or last-mile delivery vehicles, 48 V systems reliably provide power up to approximately 15 kW. At the same time, the system architecture remains lean, benefiting both development and subsequent vehicle design.
Reference designs for charging and drive units
Rutronik is focusing on two practical reference designs for implementing efficient 48 V systems for low-speed electric vehicles: an on-board charger (OBC) and a universal traction inverter. Both designs target cost-efficient series applications in the urban mobility environment and allow developers to quickly begin functional validation.
48 V on-board charger (3.3 kW): The reference design (Fig. 1 and Fig. 2) is based on a half-bridge LLC resonant converter topology with an upstream PFC stage and is implemented entirely with silicon-based semiconductors. The choice of switching frequency and transformer was specifically tailored to achieve an optimal price-to-performance ratio.
Rectification on the input side is performed by a thyristor-controlled diode bridge, while Schottky diodes are used on the output side. The resonance circuit components – especially the RF transformer and power modules used – are precisely matched to each other, thereby ensuring high efficiency of the overall circuit. The design supports communication in accordance with the CCS standard, making it suitable for use in modern wall charging stations. The goal is to deliver a cost-effective solution for 48 V charging applications in LEVs that is both functional and cost optimized.
48 V traction inverter (10 kW continuous power/15 kW peak power): The universal traction inverter (Fig. 3 and Fig. 4) is designed for continuous currents up to 350 A (or 600 A for 60 s). With its CAN interface and analog and digital I/Os, the system can be controlled flexibly. All electronics are located on a compact PCB featuring state-of-the-art MOSFETs and a top-side cooling concept. Therefore, the MOSFETs do not need to be cooled by the PCB but can be connected directly to a heat sink, such as the base plate, using a thermal interface material (TIM). The thermal resistance between the MOSFET package and the base plate is thus lower than with heat dissipation through the PCB. This contributes to the thermal performance and high power density of the overall system. The single PCB design reduces the complexity of the overall system. This eliminates the need for error-prone connectors between PCBs. Potential target applications include electric powertrains in L7e-class low-speed electric vehicles, such as golf carts, LEV scooters and light urban transport vehicles.
The two reference designs not only demonstrate the technical feasibility of the topologies but also serve as guidance for selecting suitable power semiconductors, components and system architectures. Automotive developers benefit from complete bills of materials (BOMs), circuit diagrams and thermomechanical concepts, all available through Rutronik’s technical sales department. This reduces development time and significantly speeds up the time-to-market for new mobility solutions.
Collaboration with prospects
The shift toward electric mobility is creating new technological, geopolitical and economic challenges for suppliers, subcontractors and system partners worldwide. Especially in times of global uncertainty, strategic alliances, market-driven product approaches and reliable supply chains are crucial for developing sustainable micromobility solutions.
Against this backdrop, the close partnership between Rutronik and Vishay takes on a particularly important role. Ever since the establishment of the Automotive Business Unit in 2014, Vishay, as a key supplier, has been closely involved in developments, especially in developing 48 V system solutions for light electric vehicles.
One example of this successful collaboration is the joint development of the efficiency-optimized reference designs for charging and drive units in the 48 V range presented here. These solutions enable urban mobility requirements to be addressed with technically mature, practical and economically viable systems.