Indirect field oriented control of an induction motor fed by a bidirectional quasi Z-source inverter

This paper proposes a new closed loop speed control of an induction motor fed by a bidirectional quasi Z-source inverter (BqZSI), the speed control is based on the indirect field oriented control (IFOC) strategy. The IFOC is implemented based on a voltage pulse width modulation (PWM) with voltage decoupling compensation to insert the shoot-through (ST) state within the switching signals. A dual loop controller is designed, based on a third order small signal model, to control the BqZSI capacitor voltage. The proposed speed control method, with reduced DC input voltage compared with the standard adjustable speed drives (ASD) using voltage source inverter (VSI), are able to change the motor speed from zero to the rated speed with the rated load torque. The performance of the proposed speed control methods is verified by MATLAB simulation of a 15 kW induction motor fed by a BqZSI. The simulation results during different operation modes verify the validity of the proposed closed loop speed control method.