The excitation control of a 12/3 phase dual stator-winding induction generator

This paper presents a novel stand-alone dual stator-winding induction generator (DWIG) on the basis of the new idea of electric power integration. The 2000 kW/6521 RPM generator and its controller are to be designed. The experimental 1:100 experimental prototype generator and its controller were designed in 2003 and many experiments were done also. This generator has two sets of stator-windings. One, referred to as the 12-phase power winding, is connected with four 3-phase full bridge rectifiers to this 12-phase winding to supply a high-quality DC power. The other is a 3-phase winding. A typical two-level PWM voltage source inverter is connected to this winding and the PWM inverter generates reactive current to the generator. It is equivalent to a static VAR generator (SVG), and it is called a static excitation regular (SER). The excitation control theme is discussed in detail, and it is combined with the fixed capacitors and a SER. The fixed capacitors are wye-connection to the power winding. When no load or small load, the capacitors can supply some excitation current and the generator could supply DC power. The control object of the SER is to maintain the DC output of the power winding constant. The paper presents a control methodology based on 3-phase stator voltage-oriented (SVO) to regulate the DC voltage. Theoretical deductions are presented in order to validate the proposed control algorithm. Experimental and simulation results are also proposed and the output DC voltage could maintain constant in spite of the variation of the prime mover speed and the load. These results show that the system is a high-quality DC power source with a fast response. So the excitation control theme combined with the fixed capacitors and a SER are valid and efficient.