Power management units for drones

A power management unit (PMU), also called a power distribution unit (PDU), routes electrical power from the sources (batteries, generators, fuel cells) to every load on the aircraft: propulsion, avionics, payload and actuators. It protects each circuit, monitors consumption and, in larger aircraft, switches between sources and isolates faults.

Functions

• Distribution: splits power into protected channels with the right voltage for each load.
• Protection: electronic circuit breakers or fuses that trip on over-current, short circuit or over-voltage. Solid-state power controllers (SSPC) can be reset remotely.
• Conversion: DC-DC converters that produce stable low-voltage rails (for example 5, 12 or 28 V) from the main bus.
• Source management: combines or switches between batteries, generators and ground power, with redundancy.
• Monitoring: voltages, currents and temperatures reported to the flight controller over CAN, serial or Ethernet.

Key specifications

• Input voltage range and number of sources.
• Number of output channels, their voltage and current rating.
• Type of protection: fuses, electromechanical breakers or SSPC, and whether trip limits are configurable.
• Redundancy: dual buses, diode-OR inputs and independent channels for critical loads.
• Telemetry and control interface.
• Mass, size and environmental qualification, for example to DO-160.

Why it matters

Electrical failures are a frequent cause of drone accidents. A well-designed power system makes sure that a fault in the payload or a single motor cannot take down the flight controller, and that the operator knows how much energy is left.

Manufacturers in the directory

Examples include Safran Electrical & Power, Astronics, Currawong Engineering and Mauch Electronic. See also batteries.