Keywords: cycloconverters, input current shaping, SMPS, variable frequency drives, input current THD, total harmonic distortion, input power factor, single–phase switch mode, power quality, sliding mode control, SMC
Single–phase switch mode high power quality cycloconverters
In this paper, we propose three new single–phase switch mode cycloconverters. Instead of simple switching scheme of P– and N–controlled rectifier–converters, high frequency switching of full bridge rectified outputs has been used with the help of SMPS topologies. This enables the input current switching at high frequencies and effective current shaping using passive filters. The input supply is an AC source followed by a full bridge rectifier circuit, the output of which is fed to the SMPS converters. The output voltages of the proposed cycloconverters are controllable step–up and step–down in nature with duty cycle control of switching regulators. Total Harmonic Distortion (THD) of the input current of the proposed circuits is minimised by input filters before the rectifier. Input power factor and efficiency of the circuits are high. Open loop sliding control technique is applied to ensure good power quality at desired performance. Details of operation and circuit performance are presented in this paper.