An electrical power unit is disclosed. The electrical power unit includes a controller configured to generate a first control signal based on a first operational state of an engine, a multiphase electrical machine including a plurality of three-phase windings; and an electrical power conditioning subunit operatively coupled to the controller, where the electrical power conditioning subunit comprises a plurality of converters, where at least one converter is electrically coupled to a corresponding three-phase winding of the plurality of three-phase windings based on the first control signal, and where the electrical power conditioning subunit is configured to transmit a first electrical power from the at least one converter to the corresponding three-phase winding, where the multiphase electrical machine is configured to generate a mechanical power based on the first electrical power and rotate a crankshaft operatively coupled to the engine based on the generated mechanical power to start the engine.