Exicom Powertrain Engineer Interview: Rounds, Questions and Preparation

What the job involves

A Powertrain Engineer in the EV and cleantech sector designs, integrates, and validates electric drive systems, including motors, controllers, transmissions, and battery interfaces. At fast-growing companies like Exicom, you may work on power electronics for chargers, battery management systems, or complete powertrain solutions for two- and three-wheelers. Day to day involves simulation, testing, component selection, and cross-functional coordination with firmware, thermal, and manufacturing teams.

Role and Technical Knowledge

1. 1

   Explain the working principle of a BLDC motor and how it differs from a PMSM in EV applications.

   Cover back-EMF, commutation (trapezoidal vs sinusoidal), torque ripple, efficiency, and typical use cases in two-wheelers vs cars.

2. 2

   What are the key considerations when sizing a motor and inverter for a given vehicle load profile?

   Discuss peak and continuous torque, thermal limits, gear ratio, battery voltage, and efficiency maps.

3. 3

   How does a Battery Management System (BMS) ensure safety and performance in a lithium-ion pack?

   Mention cell balancing, state of charge (SoC) and state of health (SoH) estimation, overvoltage/undervoltage protection, and temperature monitoring.

4. 4

   What are the differences between a DC-DC converter and an onboard charger in an EV powertrain?

   Explain their functions, power levels, isolation requirements, and how they interact with the high-voltage bus.

Practical Scenarios and Problem Solving

1. 5

   During a test drive, the vehicle experiences power derating at high ambient temperature. How would you diagnose and address this?

   Suggest checking motor and inverter temperatures, coolant flow, derating thresholds in firmware, and possible upgrades to thermal management.

2. 6

   You need to reduce the cost of a powertrain for a low-speed electric scooter without compromising safety. What changes would you propose?

   Consider motor type (e.g., BLDC vs PMSM), sensorless control, simpler BMS, fewer sensors, and trade-offs in performance and reliability.

3. 7

   How would you validate a new motor controller before integrating it into a full vehicle?

   Describe bench testing with dynamometer, load banks, CAN logging, fault injection, and gradual integration from component to system level.

4. 8

   What steps would you take if a battery pack shows unbalanced cell voltages after a few charge cycles?

   Outline checking BMS balancing circuit, cell quality, charging profile, and potential need for cell replacement or BMS firmware update.

Behavioural and Teamwork Questions

1. 9

   Tell me about a time you worked on a team project where a technical disagreement arose. How did you handle it?

   Use STAR method: describe the situation, your role, how you listened and used data to resolve, and the positive outcome.

2. 10

   Describe a situation where you had to learn a new tool or technology quickly for a project.

   Highlight self-learning, resourcefulness, and application of the new skill to deliver results under time pressure.

3. 11

   Give an example of a time you made a mistake in a design or calculation. What did you learn?

   Show accountability, root cause analysis, corrective action, and how you prevented recurrence.

HR and Motivation Questions

1. 12

   Why do you want to work in the EV and cleantech sector, and specifically in a powertrain role?

   Connect personal interest in sustainability, technical fascination with electric drivetrains, and desire to contribute to India's EV growth.

2. 13

   How do you keep up with the latest developments in EV technology?

   Mention specific sources: IEEE papers, SAE events, online courses, industry news, and personal projects.

3. 14

   Where do you see yourself in three years in this role?

   Show ambition to grow into a senior engineer or specialist, with increasing ownership of design and validation, while staying hands-on.

4. 15

   Are you comfortable working in a fast-paced startup environment with changing priorities?

   Emphasise adaptability, willingness to learn, and examples of thriving in dynamic situations from college projects or internships.