#7 Interview With Manoj RPodcast ·
Discussions on Power Electronics (and systems design) for space and aeronautical applications with Manoj R of the Indian Space Research Organisation (ISRO).
- Engineer at the power conditioning lab, Inertial Systems Unit (ISU), Indian Space Research Organisation (ISRO)
- M.Tech in Electronics Design at Indian Institute of Science
- Previous work places: Vikram Sarabhai Space Centre (Trivandrum), ISRO Satellite Centre (Bangalore)
- DC/DC converters and their miniaturization
- Designing for low SWAP-C (Size, Weight, and Power, Cost)
- Powering sensors and acquisition systems with low noise
- Power range: 2W to few kW
- B.Tech project: Power harmonic distortion measurement using MATLAB: data acquisition on a laptop using the audio-in connector
- Importance of learning on the job
- Major challenges in space: Environment
- Being within specification in a wide ambient temperature range: -40C to 120C
- Exposure to thermal cycling
- Stringent EMI/EMC requirements because of other critical systems connected to the same DC bus
- Space radiation (ionizing)
- Launch vehicles are exposed to this for a short duration
- Geosynchronous space crafts work for >15 years without servicing
- Operation in vacuum: Need tight control over materials used
- Thermal management of power devices: Even 4W of power dissipation in a single device is challenging, conduction is the only mode of taking out heat from the device (no convection in absence of air, not much thermal radiation at lower temperatures owing to Stefan’s law)
- Spacecraft thermal management: Using reflectors, radiators, heaters (when spacecraft is in shade), heat pipes
- Solar panels, energy storage (batteries), and energy management on the spacecraft
- Transferring space technology to terrestrial applications: renewable-only energy systems, DC-only systems, space crafts and EVs are both essentially battery-based systems with minimum SWAP requirements
- “If you look at power, you start imagining the origin of things: How does something really start up? Where is its source of power? Where and how does the power flow? Who needs it? How much is needed? When you look at all this stuff, you start understanding the system much better.”
- “When you work in power electronics, you have to interface with almost everyone around – because nobody can work without power. You start interacting with the digital team, communications team, thermal, mechanical, almost everyone.”
- “Adoption of wide bandgap (WBG) devices in power electronics is a turning point similar to the introduction of IGBTs in the high power conditioning levels.”
- Key skills for working in power electronics: analog electronics, working of semiconductor devices, magnetics design
- “Back in my bachelors days, I used to believe that it’s the voltage that you should look at all the time, to know what is actually happening. Slowly with more experience, it was wonderful for me to come to know of current probes. Early in your career, start looking into current waveforms and not just in textbooks. If voltage is the cause, current is the result. If you want to know the result, look at the currents.”
- Approach to innovation:
- ISRO works in small strong teams.
- Bottom-up approach: ideas coming from the grassroot level are put into a common pool and reviewed so that the best ones come up and they get funded.
- Problem solving by divide-and-rule: break up a problem into smaller problems and distribute to the people by skillset.
- Special focus on defining interfaces clearly.
- ISRO hes university satellites too, accepts students for project work.