**Author details**

462 Induction Motors – Modelling and Control

**Figure 25.** The stator current in stationary state.

x11 is the rotor speed, x12 is the variable proportional to electromagnetic torque, x21 is the square of rotor flux and x22 is the additional variables, id is the dc-link current, usα,β are the capacitor voltage components, KTL is correction element (load torque), isα,β are the stator

In this chapter two approaches to control of induction machine supplied by current source converter are presented. The first of them is voltage multi-scalar control based on PI controllers or backstepping controller. The voltage approach seems to be a better solution than the second one: current control, because the control system structure is more simple than the current control structure. The voltage in dc-link is the control variables obtained directly from decouplings. The current in dc-link is not kept at constant value but its value depend on induction machine working point. The current control gives higher losses in dc-link and higher transistor power losses than the voltage control. The power losses can be minimized by modulation index control method but the control system is more complicated. Both control systems lead to decoupling control path and sinusoidal stator current and voltage when space vector modulation of

where:

current components.

transistors is applied.

**9. Conclusion** 

Marcin Morawiec *Gdansk University of Technology, Faculty of Electrical and Control Engineering, Poland* 
