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power installed in the new generation of vehicle. The standard did not become very popular because of its high implementation costs, which would require the redesign of all electrical and electronical subsystems [26]. Instead, most producers were oriented on systems with two volt- age levels: high voltage for propulsion and low voltage for auxiliary and electronic subsystems. A starter-alternator system involves the use of a static frequency converter for the driving of the electrical machine. The convertor will operate in both the inverter and rectifier regimes. In the rectifier operating mode, it is indicated to adopt a control strategy of the converter with the purpose of reducing losses and the harmonic content of the output currents of the machine. The techniques for the control of the converter for these two modes are the same, only the current reverses its sense depending on the operating mode. The input voltage of the static frequency converter is a DC voltage, the value of which must be kept constant in order to function optimally. The regulation of the input voltage of the converter can be done by using a bidirectional DC/DC converter with a closed loop control. An alternative to the use a DC/DC stage converter and another DC/AC converter is to use a Z-Source Converter [27]. The Z-Source Converter is more capable compared with the classical converter to operate both as a boost and buck converter due to the input impedances that give it particular operating properties. 2.2.1. Power electronics of SynRM and PMSM For the control of PMSM machine, the current of the q axis is maintained maximum in order to produce high value of the torque and zero for d axis current, respectively. Instead, for SynRM, the control strategies mean to keep the equal value of the q axis current with the d axis. In the case of PMSM with interior magnets, this control strategy does not provide maximum torque due to the additional reluctant torque [28] component that appears in expression: T  =  3 __2 ⋅ p ⋅ [ Ψ PM ⋅ i q     − ( L q −     L d   )  ⋅ i d ⋅ i q ] (1) where T is the electromagnetic torque, p is a pair pole number, ΨPM is the permanent magnet flux, iq is q axis current, id is d axis current, and Lq , Ld are q axis and d axis inductances. The reluctant component of the torque has a maximum value for id ≠ 0 and the stator current equal with π/4. Usually, the implemented control method for the PMSM and SynRM for automotive applica- tion is an indirect method, which is based on measuring the stator currents and calculating the rotor flux phasor magnitude and position using these currents and the rotor position. Thus, the flux transducer or flux estimators that are usually used in the vector control method with direct measurement of flux are eliminated. This method has a disadvantage due to the fact that the accurate determination of rotor flux phasor position requires a precise mea- surement of rotor position. Thus, the practical implementation using speed measurement for obtaining the integration of the rotor angle is not recommended. Hence, an incremental encoder position or a resolver, which has a higher cost while providing the precision required of a vector control with a good dynamic response in applications is used. In addition to this vector control method that uses position sensors for determining the rotor angle control, Performance Analysis of an Integrated Starter-Alternator-Booster for Hybrid Electric Vehicles http://dx.doi.org/10.5772/intechopen.68861 113