HPDM-350 integrated electric motor drive

HPDM-350 is an integrated electric motor drive made by H3X for aircraft propulsion and power generation. It combines a 350 kW electric motor with its inverters in a single liquid-cooled unit, which removes the separate motor controller from the installation. The maker describes it as a fault-tolerant, multisector machine intended for primary propulsion of aircraft and other high-performance systems, and it can run as a motor or as a generator.

The key figures are a continuous power of 350 kW from a mass of 50 kg (with a tolerance of plus or minus 20 percent), which gives a continuous specific power of 7 kW/kg. Continuous torque is 1238 Nm at a maximum shaft speed of 2700 rpm. Because the torque is high at a low speed, the motor suits direct-drive installations in which a propeller or fan is attached to the shaft without a gearbox, which saves the mass, volume and maintenance of a reduction stage. Peak efficiency is above 95 percent, and electrical operation is specified up to an altitude of 45,000 ft. H3X labels these values as target specifications extrapolated from tests and simulation of its lower-power machines.

The architecture has dual windings and two independent inverters. With redundant windings and inverters there is no single point of electrical failure, so the unit can continue to operate after an electrical or cooling-system fault. Onboard accelerometers and temperature sensors report the condition of bearings, windings and other critical parts, which supports health monitoring and predictive maintenance.

For integration, the maximum DC bus voltage is 900 V, so the machine is meant for a high-voltage direct-current system. Control is through two CAN interfaces, with torque, speed and, in generator mode, DC bus voltage as control modes. Cooling is by a liquid coolant circuit. The housing measures 560 mm in diameter and 226 mm in length, and the operating temperature range is -40 to 60 degrees C. A datasheet and CAD model are available from the maker.

Typical applications are primary propulsion of large uncrewed aircraft and eVTOL aircraft, hybrid-electric and turbo-electric architectures where the same machine acts as a generator, and marine and heavy-industry drives, the other sectors H3X lists.