بررسی و ساخت یک مبدل مستقیم فرکانس بدون نیاز به خازن و سلف در مدار واسط dc

In this paper a direct ac-ac converter with low distortion input/output waveforms is investigated. Direct ac-ac converters using self-commutated semiconductor switches, also known as matrix converters, have recently attracted the attention of researchers. However, these converters are still under development due to the problems associated with the commutation of bidirectional switches employed in these converters. In this paper, an ac-ac converter is proposed based on the realization of matrix converters. Absence of bulky and unreliable electrolytic capacitors, low distortion input/output waveforms with independent fundamental frequency and employing two conventional power electronic building blocks are among important advantages of the proposed converter. The PWM patterns of two converters must be synchronized in order to achieve harmonic-free waveforms. This calls for an advanced PWM generation method as compared to conventional PWM strategies. Detailed derivation of the PWM signals based on double space-vector strategy is presented. Simulation results show various aspects of the system operation. The theoretical results are verified using a laboratory prototype. Experimental and simulation results show good agreement.