A dual doubly-fed generator system supplied by a five-phase voltage inverter

The paper presents a new conception of applying a system configuration of two machines supplied by a five-phase inverter with a common leg. The space vector pulse width modulation (SVPWM) technique was used for the given configuration of the dual generator system to ensure a dual three-phase output from a single five-phase inverter. Supplying two three-phase doubly-fed induction generators (DFIG) with a five-phase voltage source inverter (VSI) is not new. Two- and multi-motor drive systems are widely used in industry. Electric vehicles (EVs) and traction systems are the most popular application areas. However, there are no solutions for generator systems. The main idea of this paper is to apply a dedicated SVPWM technique for two-motor systems as an alternative to a two-generator system. The output voltages of the five-phase inverter supplying two three-phase rotors for both generators can be generated independently, with different frequencies and amplitudes. The concept of independent control of two generators using the field-oriented control method was verified in an experimental system for 2kW generators. Tests confirmed the usefulness of the proposed solution, with the ability to independently control each generator, as well as the effectiveness of the modulation strategy used to generate high-quality energy with low voltage harmonics. The THD values for the voltages of both generators did not exceed 5% in any of the cases considered.