Abstarct: In recent years, Pulse Width Modulation (PWM) inverters have found wide applications in power systems. Utilizing parallel operation of inverters cause to obtain a larger power capacity and to improve system reliability. Control problems for parallel-connected inverters are tight output voltage regulation and proper current distribution among inverters. In this research, three different control systems are employed. The first control system is baxsed on Characteristic Loci method (Approximate Commutative Controller). The second and the third control systems are H∞ and LQG controllers. For proper current distribution, ACSS and 3C techniques are used. Simulation results of single, double and triple inverter systems with different kind of loads and parametric uncertainties are investigated in Matlab software. The simulations have demonstrated the validation of operation of control systems in voltage regulation and current distribution. In addition, the operations of the control systems, which have been applied on parallel-connected inverters, are compared with each other for different criteria.