Improving the efficiency of battery-electric vehicle powertrains is a key to increase their range per charge and expand transportation electrification. Although the peak efficiencies of electric motors equipped with rare earth magnets exceed 90%, practical drive cycles and powertrain architectures frequently operate outside of the peak efficiency speed/load region. At 10% of the maximum torque of an electric vehicle, efficiency of the electric motor drive is more commonly 70-85%. In addition, the most efficient electric motors use magnets with large content of Neodymium or Samarium, both of which are expensive and have limited sources of supply.
Tula’s control architecture – called Dynamic Motor Drive (DMD®) – mitigates the light-load efficiency losses of electric motors while simultaneously reducing or eliminating the reliance on rare-earth materials. By using the DMD pulse density strategy for electric motor control, inverter losses and core losses are mitigated. At high loads, experiments have proven efficiency improvements of 2% on induction motors, with more improvements possible at lighter loaded conditions. This study projects similar efficiency improvement for a synchronous reluctance motor drive in the WLTP. Those improvements enable reduced battery size and increased range while lowering total energy consumed, and do not require hardware changes to the motor or vehicle.
This work will detail the controls methodology used to achieve those gains, the optimization of motor design for this new control paradigm, and the experimental results of that system in use.

After a motor is designed in JMAG, a designer would typically need to test the designed motor in a drive environment so that the designer can evaluate if the motor performs as expected and iterate the design if necessary. Setting up the drive system with the proper current, torque, and speed control, however, is not trivial considering the motor nonlinearity and the complexity of designing the control loops. Through its link with JMAG and JMAG-RT, PSIM’s Motor Control Design Suite makes this process considerably easier. Based on motor parameters and operating conditions, the Design Suite can come up with a functional drive system that is ready to simulate in a matter of minutes. The drive system incorporates advanced motor control algorithms such as Maximum-Torque-Per-Ampere control, field weakening control, and Maximum-Torque-Per-Volt control to maximize the power, efficiency, and speed range. With other features from PSIM, it is also possible to quickly generate and evaluate the efficiency maps of the motor, inverter, and the entire drive system. The Motor Control Design Suite relieves motor designers from the burden of designing the complex drive system and allows them to focus on the motor design and performance optimization.

Automotive industry has widely accepted Model Based Design (MBD) for control software development; motivated by software’s safety critical nature and the need to comply with ISO 26262. The problem in the past was lack of ultra-high fidelity real-time Controller Hardware in the Loop (C-HIL) simulation of inverter and electric motor thus creating a gap in the workflow when evolving a model from Model in the Loop (MIL) and Software in the Loop (SIL) to C-HIL. In this talk we demonstrate Typhoon’s ultra-high fidelity motor drive Hardware in the Loop (HIL) simulation with seamless integration with JMAG FEA machine design software. We will show a typical workflow for design and testing of EV drivetrain starting with JMAG FEA motor design, followed by export of spatial-harmonic PMSM motor model, with iron losses included, from JMAG-RT into Typhoon HIL simulation environment, followed by controller Hardware in the Loop simulation in Typhoon HIL HIL404 simulator interfaced with a real Engine Controller Unite (ECU) in the loop. Furthermore, we will briefly describe HIL interface towards the test automation and test management software.

As electric vehicles become increasingly more mainstream, an increasing level of refinement is required for a modern driving experience. As efficiency and NVH targets become increasingly more stringent, an integrated CAE modeling approach is required to predict system behavior early in the development cycle. This integrated CAE approach requires multi-disciplinary modeling, of electromagnetics, mechanics, and thermal systems together. While these analyses may typically be managed by different engineers, or even different departments, there is a growing need for increased collaboration. This presentation will detail several avenues for increased collaboration of motor integration to improve NVH behavior.

Efficient cooling of the different thermal components is paramount in advancing the design of electric motors in the future. Computational Fluid Dynamics is poised to be a critical tool in accurately characterizing the applicability of the different cooling strategies available for various motor designs. In this presentation, we use a combined Computational Fluid Dynamics/Finite Element Method approach to study two motor designs adopting different cooling strategies. The first study is with an air-cooled switched reluctance motor using coil windings typically used in power tools. The second study showcases an oil drip cooled traction motor with bar windings often used in electric vehicles. In CONVERGE, the volume mesh upon which the governing equations are solved is created automatically and refined dynamically based on the solution at any given time. This enables a highly efficient calculation especially when dealing with complicated geometries with intricate solid components.

All-electric aviation is increasingly at the forefront of research and development with the promise of zero-carbon air travel and a 40% reduction in operating costs for short-haul flights. According to the Advanced Research Projects Agency-Energy (ARPA-E), a propulsion system efficiency greater than 93% and specific power greater than 12 kW/kg is required for an electric narrow-body commercial airliner to complete a typical 5-hour flight, which represents a 3x step change over the specific power of commercially available solutions. This presentation will discuss the technology development required to achieve this step change, starting with presenting an alternative framework for the scaling of machine specific power that addresses ubiquitous misconceptions about specific torque and winding current density, continuing to identify areas of performance bottlenecks, and culminating with the materials and manufacturing technologies required to overcome these barriers to performance. Ultimately, an overview will be presented for the design of a synergistically cooled integrated motor drive composed of a highly saturated, high frequency machine with additively manufactured coils and a silicon carbide inverter. Highlights of analysis using JMAG Designer will be included to provide illustrative examples.

A novel toroidal motor structure consisting of a rotor wrapped around the stator was designed in order to maximize the electromagnetic interaction within the motor volume. The motor utilizes simple ring-shaped magnets and toroidal concentrated windings with a soft magnetic composite core to enable 3-D flux paths. The proposed design is simulated using 3D electromagnetic and thermal FEA. The simulation results show that the proposed design can achieve at least 40% and 30% higher output torque compared to radial and axial flux PMSMs, respectively. In addition, 3D FEA thermal analysis shows the potential for a highly efficient magnet cooling that can enhance the motor reliability at high loading conditions and enable the possibility of using lower grade magnets.

In recent years, electric power conversion systems have drawn a lot of attentions due to rapidly growing interests in transportation electrification and distributed energy system (DER). High-performance power electronics, batteries, and electric machines are the key enabling technologies for accelerating this trends, and significant efforts have been devoted to developing more efficient, reliable, and cost-effective power conversion systems. This research aims to shed light on reliability of motor drive systems for safety-critical applications such as hybrid electric/electric vehicles, off-road vehicles, electrified aircrafts, and ships.
A modular multiphase fault-tolerant motor drive topology with a new vector control technique is proposed to achieve extremely high-level of reliability and performance. The design and operation of the proposed fault-tolerant motor drive are validated analytically, and investigated by extensive simulations (circuit, control, and motor FEA), followed by experimental verification. It has been analytically and experimentally verified that the proposed fault-tolerant motor drive can tolerate up to four-phase open-circuit faults and two-phase short-circuit faults. Several new open- and short-circuit fault compensation strategies have been proposed and investigated in detail.