The Incredible Shrinking Motor Drive: Accelerating the Transition to Integrated Motor Drives

A technology revolution is unfolding around us as every major mode of transportation is in some stage of electrification, whether on land, sea, or in the air. All of these transportation modes depend on electric machines that play critical roles in both propulsion systems as well as in a wide variety of accessory equipment. Fuel economy and reduced emissions of greenhouse gases and other pollutants are major driving forces for electrified transportation. Despite the significant differences between these varied transportation modes, they all share strong motivations to make their electric machines and adjustable-speed drives smaller, lighter, and more efficient. An excellent example of this trend for the power electronic drives is provided by comparing the drive units in the Tesla S (2012) and Tesla 3 (2017). As shown in the side-by-side views provided in Figure 1, the drive unit shrank in size from an enclosure that matched the size of its main traction motor to a much smaller unit that, at first sight, appears to be a non-descript end-bell attached to one end of the motor. Rather than focusing here on how this impressive reduction in mass and volume was achieved (addressed later in this article), the key point here is that similar technology trends are under way in many of the other transportation modes as well, making electrified transportation increasingly appealing and competitive in the process.