Off-grid power generating apparatus for providing dual output voltage

An off-grid power generating apparatus comprising:

• an engine;
• an alternator including:
• a rotor coaxially coupled to the engine, the rotor including a plurality of symmetric phase windings,
• a switch operatively connected with the electrical load, the switch being movable between a first position and a second position by a user;
• a stator with a single phase winding that includes an output portion, wherein the output portion has a first segment and a second segment each of which has at least one coil configured to generate an induced voltage, the first segment and the second segment are operatively and separately connected with the switch, the first segment and the second segment are configured to be connected in series at the first position of the switch to provide a high voltage to the electrical load via the switch, and connected in parallel at the second position of the switch to provide a low voltage to the electrical load via the switch;
• and one or more sensors configured to measure operation data of the apparatus;
• and
• an excitation control device operatively connected to the engine and the alternator, wherein the excitation control device is configured to:
• control the induced voltage generated in the single phase winding of the stator by regulating a rotating magnetic field generated in the phase windings of the rotor;
• calculate load powder of the electrical load at least in accordance with the operation data measured by the one or more sensors;
• and
• regulate speed of the engine in response to the calculated load powder;
• wherein the alternator further comprising a frequency conversion device operatively connected with the single phase winding of the stator, wherein the frequency conversion device is operatively connected with the phase windings of the rotor and supplies an excitation voltage to the phase windings of the rotor for establishing the rotating magnetic field;
• wherein the frequency conversion device comprises:
• a direct current bus voltage regulator operatively connected with the single phase winding of the stator, the direct current bus voltage regulator being configured to receive and rectify the excitation voltage from the single phase winding of the stator, and output a rectified direct current bus voltage;
• and
• an inverter operatively connected with the direct current bus voltage regulator, the inverter being configured to receive the rectified direct current voltage, and supply an alternating current voltage to the plurality of symmetric phase windings of the rotor for establishing the rotating magnetic field.