58 March/April 2024 | E-Mobility Engineering Modern inverters are including more intelligent features to work with other vehicle systems, reports Peter Donaldson The pursuit of power Inverters do the conceptually straightforward job of converting an electric current from DC into AC form. As such, they create an essential link between the energy storage system and the motor. Modern inverters use solid-state semiconductor switches, connected to form combinations of half-bridges and activated by smaller switching circuits known as gate drivers, which in turn are under the control of processors that implement control logic embodied in hardware, software or both. Inevitably, there is a push for greater efficiency to reduce energy losses during power conversion and thereby eke more mileage from a battery charge, says an expert from a developer of advanced semiconductors and control algorithms. At the same time, vehicle OEMs and powertrain specialists are pushing for lighter, more compact inverters without sacrificing performance. High torque- and power-density in both volume and weight terms are crucial to save space in a vehicle and reduce its overall weight, particularly as inverters are integrated into electric drive units (EDUs). To meet these demands, inverter developers are increasingly turning to wide bandgap (WBG) semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN). Compared with silicon insulated-gate bipolar transistors (IGBTs), transistors made from these two materials can operate at higher temperatures, voltages and switching frequencies, all of which contribute to higher power-density and efficiency. However, this also generates more heat in smaller spaces, driving the need for advanced thermal management. Inverters are expected to work in vehicles for decades over hundreds of thousands of miles in a wide range of conditions, so reliability and durability are important. In early electric vehicles, the inverter was engineered as a stand-alone unit, but the recent shift to integration with other components brings challenges in optimising packaging, says a specialist in electric machines, power electronics and control systems. Understanding the location of the inverter on the vehicle, along with the associated environmental constraints that must be considered, has an impact on engineering and development requirements. This integration with other vehicle systems means that modern inverters must also incorporate more Inverters are often mounted close to or integrated into the housings of motors, making understanding of the operating environment crucial for reliability (Image courtesy of Allegro Microsystems)
RkJQdWJsaXNoZXIy MjI2Mzk4