Husk Power Systems Embedded Systems Engineer Interview: Rounds, Questions and Preparation

What the job involves

An Embedded Systems Engineer in EV, cleantech and mobility works on firmware and hardware that control battery management systems, motor controllers, power converters and telemetry units for electric vehicles, solar inverters or microgrids. Day to day you write and debug C code on microcontrollers, interface with sensors and communication buses (CAN, I2C, SPI, UART), and test boards in the lab or on field pilots. At fast-growing companies like Husk Power Systems, you may also help integrate IoT gateways for remote monitoring of clean energy assets.

Role and sector knowledge

1. 1

   What does an embedded systems engineer do in an EV or clean energy company on a typical day?

   Mention writing firmware for battery management or motor control, testing with oscilloscopes, and coordinating with hardware and testing teams. Show awareness that field deployment and reliability matter in this sector.

2. 2

   Why do you want to work in EV, cleantech or mobility instead of a general embedded role?

   Connect your interest to solving energy access or reducing emissions, and mention specific technical challenges like battery safety or remote monitoring. Avoid generic answers about 'passion for technology'.

3. 3

   How does a battery management system (BMS) protect a lithium-ion pack in an electric vehicle?

   Cover cell voltage monitoring, temperature sensing, overcharge and overdischarge protection, cell balancing, and state-of-charge estimation. Mention communication to the vehicle controller via CAN.

4. 4

   What role does embedded firmware play in a solar microgrid or battery storage system?

   Talk about maximum power point tracking (MPPT), inverter control, charge controller logic, and sending data to a cloud dashboard. Show you understand off-grid or weak-grid conditions common in India.

Technical fundamentals

1. 5

   Explain the difference between I2C, SPI, and UART. Which would you use for a temperature sensor and why?

   Compare speed, number of wires, and multi-device support. For a simple sensor, I2C is often chosen for its two-wire bus and multiple device capability, but justify based on distance and speed needs.

2. 6

   What is the difference between a mutex and a semaphore in an RTOS? Give an example from a motor control task.

   Explain that a mutex provides ownership and priority inheritance, while a semaphore is for signalling. In motor control, a mutex might protect a shared ADC buffer, while a semaphore signals a new current sample is ready.

3. 7

   How would you debug a CAN bus communication failure between a BMS and a motor controller?

   Start with physical layer checks (termination resistors, wiring), then verify baud rate and message IDs with a CAN analyzer. Check for error frames and ensure both nodes are powered and configured correctly.

4. 8

   What is the purpose of a watchdog timer in an embedded system for an EV charger?

   It resets the microcontroller if firmware hangs, preventing unsafe charging states. Mention windowed watchdogs and the need to service them only when all tasks are healthy.

Practical scenarios

1. 9

   Your firmware reads a battery cell voltage that is 0.3 V higher than the multimeter reading. How do you investigate?

   Check the ADC reference voltage, calibration, voltage divider resistor tolerance, and grounding. Suggest measuring with an oscilloscope and reviewing the ADC driver code for sampling time or noise.

2. 10

   You need to add over-the-air (OTA) update capability to a remote solar inverter. What are the key challenges?

   Discuss reliable transfer over poor networks, image verification, fail-safe rollback, and power loss during update. Mention using a dual-bank flash and checking checksums before switching.

3. 11

   A field pilot reports that an EV's motor controller occasionally resets during acceleration. How would you approach this?

   Consider power supply droop, EMI from high currents, watchdog resets, and software stack overflow. Suggest adding decoupling capacitors, reviewing PCB layout, and logging reset cause registers.

4. 12

   How would you test a new BMS firmware before deploying it to 100 vehicles?

   Outline unit tests on a host, hardware-in-the-loop (HIL) testing with simulated cells, and a small pilot fleet with detailed logging. Mention safety limits and gradual rollout.

Behavioural and HR questions

1. 13

   Tell me about a time you debugged a hardware or software issue under a tight deadline. What did you learn?

   Use the STAR method: describe the situation, your systematic debugging steps, the fix, and a lesson about documentation or testing. Show persistence and structured thinking.

2. 14

   Describe a project where you had to learn a new microcontroller or tool quickly. How did you manage?

   Highlight self-learning through datasheets, online resources, and small test programs. Emphasise that you broke the problem into smaller parts and sought help when needed.

3. 15

   This role may involve travel to field sites or labs in rural areas. How do you feel about that?

   Show willingness and adaptability, and mention any past experience with field work or hands-on projects. Connect it to understanding real-world conditions for clean energy products.

4. 16

   Where do you see yourself in three years in the EV and cleantech embedded space?

   Aim for a realistic progression: deeper expertise in BMS or motor control, leading a small module, or contributing to system architecture. Show commitment to the sector, not just any job.