        MIHAILFLORIN STAN*, MARCEL IONEL**, OCTAVIANMARCEL IONEL*** *Automatics, Informatics and Electrical Engineering Department **Electronic, Telecommunications and Energetically Engineering Department Valahia University Targoviste, Electrical Engineering Faculty 1824 Unirii Blvd., 130082 Targoviste, ROMANIA *** Electrical Engineering Department, Politecnico di Torino, Corso Duca degli Abruzzi, 24  10129 Torino, ITALY flo.stan@gmail.com, ionel.marcell@yahoo.com, ionel.octavian@yahoo.com, www.valahia.ro, www.polito.it   Determination of the electric drive parameters (electric power, electromagnetic torque, angular speed, adaptability to almost any conditions of order etc.) requires a simulation system and fast and efficient control methods. SPICE simulation of induction machine controlled by AC inverters drive improves energy efficiency methods, to obtain a fast response, simplicity of control etc. and permits the possibility of operating in the generator regime.   Energy conversion, electric motors, power electronics, electric drive systems, control, SPICE simulation.   Nowadays, electric drives use different types of motors and they have led to major changes in processing industry. In an industrialized country, more than 60% of generated electricity is used to electric drive with electric machines. Applicability of electrical drives has increased from low power applications for a small number of areas (various instruments, computer peripherals, machine tools and industrial robots, shareholders in the paper industry, textile industry, applications and blowers pumping stations, etc..) to megawatts power, lines air compressors, fans for boilers, pumps, water supply, cement, ships propulsion, metallurgy, etc [1] [4].        For the study of the operation and computeraided analysis of induction motors fed by threephase AC voltage used to adjustable speed control systems is proposed the following model of motor. It is considered a symmetrical threephase induction motor with stator windings supplied from a symmetrical threephase voltage and source frequency is f 1 . [5] Fig.1. Reflective to writing equations of the threephase induction motor It allowed these simplifying assumptions: saturation magnetic circuit is negligible (linear magnetic circuit), stator and rotor windings are sinusoidal currents crossed wires and winding resistances are independent of temperature. Applying the law of electromagnetic induction on some „Γ” curve which crosses one motor’s winding phase and close the air on a line corresponding phase voltage at the terminals (Figure 1) induction motor equations can be written in the fixed reference system [6]. Equation established in fixed to the stator reference system: [ ] [ ][ ] [ ] S S S S dt d R i u ψ + ⋅ = (1) Equation established in fixed to the rotor reference system: LATEST TRENDS on SYSTEMS (Volume II) ISSN: 1792-4235 644 ISBN: 978-960-474-214-1