Hybrid-electric propulsion architecture and method for dissipating electrical energy in such an architecture

A hybrid-electric propulsion architecture for a multi-rotor rotary wing aircraft, comprising:

• an internal combustion engine,
• an electric generator coupled to the internal combustion engine such that in operation the internal combustion engine drives the electric generator,
• a rectifier connected to the electric generator and configured to convert an alternative current delivered by the electric generator into a direct current,
• means for converting direct current into alternative current,
• an electrical network connecting the rectifier to the conversion means, the electrical network comprising a high-voltage direct current bus,
• electrical energy storage means connected to the electrical network in parallel to the electric generator,
• electric motors connected to the conversion means so that in operation the conversion means supply the electric motors with alternative current,
• propellers coupled to the electric motors so that in operation the electric motors drive the propellers,
• the architecture being characterized in that the electric generator is an engine-generator, and in operation the internal combustion engine drives the electric generator in generator mode,
• in that, during a regeneration of electrical energy on the high-voltage direct current bus of the electrical network, depending on a state of charge of the storage means, the storage means is configured to recover the electrical energy,
• in that, during the regeneration of electrical energy on the high-voltage direct current bus of the electrical network, depending on the state of charge of the storage means, the rectifier is configured to recover the electrical energy by converting an overcurrent to a current with a reactive component degrading a power factor of an electric machine formed by the electric generator, wherein the electric machine is used only in said generator mode when said power factor is degraded,
• in that, during the regeneration of electrical energy on the high-voltage direct current bus of the electrical network, depending on the state of charge of the storage means, the electric generator is configured to operate in a motor mode so that in operation the electric generator recovers the electrical energy, by changing a quadrant of the electric generator so that it imposes a torque on the internal combustion engine which becomes consumer of the electrical energy, and
• in that, when the state of charge of the storage means is less than 60%, the storage means is configured to recover the electrical energy,
• when the state of charge of the storage means is between 60% and 80%, the storage means and the rectifier are configured to recover the electrical energy,
• and when the state of charge of the storage means is greater than 80%, the electric generator operating in the motor mode is configured to recover the electrical energy.