**6. Conclusion**

In this book chapter was presented a method to design and tune the PI regulators for the three-phase IM DTC-SVM strategy using the mathematical model complex transfer function when the machine operates at low speed. The concept of complex transfer function allows to obtain the PI regulator gains by using the closed loop system frequency response function of the controlled induction motor.

The experimental results shown the satisfactory performance of the regulator due to the fact that the speed reaches the reference value in several conditions although the complex gain was designed for a limited points of induction motor operation. Thus, the design of PI regulator has an acceptable performance although an detailed analysis considering parameters variations and other several speed operations has to be done. Due to the variable speed operation maybe it will be necessary to construct a table with PI gains designed for each desired speed or to an each speed range. The PI regulator overcomes the low speed operations shortcomings to the IM DTC-SVM strategy with a minor complexity. Thus, the complex transfer function becomes an interesting tool for design and tune PI regulator for IM drives.
