Z-Source Inverter based Indirect Field Oriented Control with Synchronous Current Injection and feed-forward CEMF compensation for an induction motor drive

In this paper, an Impedance Source (Z-Source) Inverter based Indirect Field Oriented Control for a three phase induction motor drive is presented. The Z-Source Inverter consists of traditional switching network along with a unique LC passive symmetrical network between the dc front end and the switching network. The output AC Voltage can be controlled by either controlling the shoot through duty cycle (Dsh) or Modulation Index (M). A feedback control mechanism is proposed for controlling both shoot through duty cycle and the modulation index. Indirect Field Oriented Control strategy is implemented with an added capability of Synchronous Current Injection. It avoids the issues of controller saturation at high speeds as commonly seen in the traditional Hysteresis Band Controller based drives. Feedforward CEMF (Counter Electro-Magnetic Force) compensation is also introduced in the feedback loops of the controller to enhance the overall loop response. Simulation results are used to validate the proposed solution for high speeds.