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Take the shortest path to developing traction inverters for electric vehicles

inverter electric vehicle

Governments around the world want to end sales of gasoline and diesel cars in the coming years, some as early as 2030. In this sense, the market analyst firm Statista predicts that the turnover of the electric vehicle market will experience a Impressive average year-on-year growth of 17,02% over the next four years, resulting in a market volume of $858.000 billion by 2027.

Faced with such forecasts, not only automotive companies but also various transportation sectors are rushing to introduce their biggest operational changes in decades, an activity that presents a series of challenges for the design of the electric propulsion system. For most automotive engineers, electric powertrain technologies represent a novelty that requires considerable resources and time to create safe and efficient solutions. This is where silicon carbide (SiC) can offer great advantages.

The elephant in the room for electric vehicle technology is, of course, concerns about range. While much of the attention in this regard has focused on battery capacity, both the propulsion system and the car's system electronics must also be highly efficient and capable of delivering optimal performance with adjusted consumption under conditions demanding. That is why the SiC is gaining prominence, as recognized by various top-level authorities. The UK's Advanced Propulsion Centre, for example, claims that switching from silicon to silicon carbide in power electronics could offer an approximate 10% increase in efficiency.

SiC's attributes also allow designers to create power systems with considerable reductions in size, weight and form factor. Despite all the advantages, engineers should keep in mind that designing with SiC is different from using conventional silicon MOSFETs or IGBTs. Most of the differences are related to the use of special technologies that facilitate safe operation with high-speed switching.

To reduce the cost of engineering resources and shorten time to market, fully integrated solutions are needed. CISSOID's SiC traction inverter development platform meets this demand, specifically for designing drive systems up to 850V/350kW. Among the main components of this reference design are: a 1200V three-phase intelligent power module (IPM) with a powerful gate driver that resists high temperatures and is fully optimized for the SiC application; an electric motor control board and customizable software; DC current and phase sensors, a compact liquid cooler; a specially designed and EMI filtered high density DC link capacitor.

high voltage sic inverter

Figure 1. CISSOID high-voltage SiC inverter reference design.

Each of these functional blocks plays a vital role in providing the platform's high levels of capability and modularity.

CISSOID's liquid-cooled 1200-phase 2V SiC MOSFET IPM (Figure 340) offers all the advantages of SiC technology, helping developers achieve high power density thanks to low switching losses and high temperature operation . Adding modularity to changing voltage/current requirements, CISSOID's SiC IPM portfolio consists of modules supporting a maximum current of 550A to XNUMXA. Consisting of three silicon carbide MOSFET half-bridges, the IPM reduces switching losses by at least a factor of three compared to the most advanced IGBT power modules.

smart power module

Figure 2. CISSOID 1200V 340A-550A three-phase intelligent power module (IPM).

To take full advantage of fast-switching, low-loss SiC MOSFETs, engineers need a gate driver that is fast, powerful, and robust. The integration of a gate driver and a power module provides direct access to a fully validated solution optimized for switching speed and losses, robustness against dI/dt and dV/dt, and protection. of the power stages.

CISSOID's optimized gate driver offers peak currents greater than 10A, as well as the ability to operate at an ambient temperature of up to 125°C. Therefore, the optimized gate driver helps minimize the number of iterations necessary for perfect performance and thermal management of the module.

The ability of SiC power modules to switch at higher speeds and operate at higher frequencies makes it critical to access controller technology that can execute real-time algorithms more quickly.

Based on the OLEA FPCU® T222 from Silicon Mobility, CISSOID has developed a card that offers real-time processing, control and functional safety (ISO 26262 ASIL-D ready) for automotive motor control applications. Control hardware and software effectively process signals from motor position, current and temperature sensors. Of note, the mechanical and electrical integration between the control board and the IPMs removes another obstacle from the developer's path.

The platform integrates the OLEA APP INVERTER control software from Silicon Mobility (Figure 3); Additionally, engineers can use OLEA COMPOSER design tools to shorten the time required to develop and optimize engine control software.

olea control software

Figure 3. OLEA APP INVERTER control software from Silicon Mobility.

There are two other notable points about the design. First, CISSOID offers a 3D-printed cooler reference design for rapid power module cooling and evaluation (Figure 4). Secondly, the company has collaborated with NAC Semi and Advanced Conversion to create a high-density DC link capacitor with very low inductance and ESR that gives developers complete freedom to take advantage of the fast switching capability of MOSFETs. Sic.

sic investor platform

Figure 4. CISSOID SiC inverter platform, including SiC IPM, control card, compact liquid cooler, and low ESL DC link capacitor.

Finally, CISSOID's exclusive modular hardware and software platform makes it possible to develop very compact, efficient and highly safe SiC-based traction inverters or active rectifiers in just a few months. Regarding the deadlines that manufacturers usually handle, this can shorten the development period of the SiC inverter by between one and two years.