High performance current regulator for a field-oriented controlled induction motor drive

In this paper, a novel strategy of current regulation of a field-orientation induction motor drive using the GTO inverter is proposed, which is based on a multivariable state feedback control with an integrator. The controller is designed by pole placement technique of multivariable system regulation theory. In addition, feedforward control is included in the control laws to improve transient responses. For the linear state feedback control, the rotor flux is separated as a disturbance and is estimated with a reduced-order state observer. A good steady-state performance is obtained by means of an integral compensation and symmetrical space voltage vector PWM, and fast transient response is also feasible since the required voltage is directly calculated from the feedforward control. Also, it is demonstrated that an instantaneous current control without the calculation time delay can be implemented. The excellence of the proposed current regulation scheme is verified by experiments for the GTO inverter-fed induction motor drive system controlled by a DSP-TMS320C30