HPDM-500 integrated electric motor drive

H3X HPDM-500 is an integrated electric motor drive for aircraft propulsion and power generation, made by H3X Technologies. It combines a 500 kW permanent-magnet electric motor with its own silicon carbide inverters in one liquid-cooled housing, so the machine and the power electronics are delivered as a single unit. It can be operated as a motor or as a generator.

The unit targets propulsion systems for large electric and hybrid-electric aircraft, eVTOL platforms and heavy unmanned aircraft in the aerospace sector, and the maker also lists defense, marine and heavy-industry applications. Its design uses two independent windings and two inverters, a multisector architecture in which there is no single point of electrical failure and operation continues after an electrical or cooling system fault, a property that simplifies a safety case for propulsion.

The key figures are as follows. Maximum continuous power is 500 kW and maximum continuous torque is 590 Nm, with a maximum speed of 10,000 rpm. Mass is 46 kg, giving a continuous specific power of 10.9 kW/kg and a continuous power density of 32 kW/L, which lets a designer compare the unit against separate motor and inverter combinations. Peak efficiency is 96-97%. The maximum high-voltage DC bus voltage is 850 VDC, and the maximum altitude is 70,000 ft. The maker states that these values, together with the power, torque and efficiency curves, are approximate and based on dynamometer data and simulation.

Integration details: the housing is 242 mm in diameter and 341 mm long, and the operating temperature range is -40 to 60 degrees C. A single additively manufactured cooling jacket cools the stator and the power electronics at the same time, with liquid coolant. The communication protocol is CAN, and the control modes are torque, speed and, in generator mode, DC bus voltage. Two units can be stacked for 1 MW.

Construction details relevant to thermal limits are the stator winding, which has a fill factor above 70%, a bulk thermal conductivity above 5 W/m-K and a rating of 265 degrees C for 20,000 hours, and the self-sensing rotor position algorithm that removes the need for a separate position sensor in the inverter control.