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Case study: Sewer inspection robot

Low weight, low noise solution

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Customer’s challenge

Improved sensors, autonomy, mobility and AI (allowing deep learning) is enabling inspection robots to replace humans, especially in hazardous or confined areas like inside pipelines or in storage tanks. Manufacturers are looking for smaller, more robust solutions with ever improved resolution, repeatability and operating range. This manufacturer of tethered sewer inspection robots was looking to improve the sensor resolution and quality of video images without increasing the size of the platform. The key goals were:

  • Allow easier handling and room for more sensors by reducing power supply size and weight
  • Minimize interference with cable carrying video feed
  • Reliable operation in a harsh environment
Sewer inspection robot

The Vicor solution

The 48V (SELV) supply to the tether was provided by a PFM AC-DC converter.  On board the robot the three rails were provided by three individual regulators.

Key benefits

Key benefits

ZVS buck and buck-boost regulators offered high power density and low weight (0.8g)

ZVS buck and buck-boost regulators offered high power density and low weight (0.8g)

Low noise ZVS topology minimized filtering required

Low noise ZVS topology minimized filtering required

High efficiency (up to 92.5%) reduced heat, increasing reliability in high ambient temperatures

High efficiency (up to 92.5%) reduced heat, increasing reliability in high ambient temperatures

Power delivery network

The power delivery network: The 48V tether supply was provided by a PFM AC-DC converter. At the robot the low power 5V and 3.3V rails were provided by ZVS Buck regulators. The higher power 12V motor supply rail was provided by an array of three ZVS Buck-Boost converters that compensated for large voltage drops in the 600m tether. To analyze this power chain go to the Vicor Whiteboard online tool.

Learn more about the modular approach power.

Vicor power delivery network for Sewer Inspection
PFM product image

PFM AC-DC converters


Isolated regulated


Input: 85 – 264V


Output: 24V or 48V


Power: Up to 400W


Peak efficiency: Up to 92%


110.55 x 35.54 x 9.40mm


ZVS buck family page

ZVS buck regulators


Non-isolated regulated


Inputs: 12V (8 – 18V), 24V (8 – 42V), 48V (30 – 60V)


Output: 2.2 – 16V 


Current: Up to 22A


Peak efficiency: Up to 98%


As small as 10.0 x 10.0 x 2.56mm  


ZVS buck-boost regulators image

ZVS buck-boost regulators


Non-isolated regulated


Input: 8 – 60V


Output: 10 – 54V


Power: Up to 150W continuous


Efficiency: Over 98%


10.5 x 14.5 x 3.05mm


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