A Novel Diode Rectifier with a Series Connected Chopper for Reduced Input Current THD

Abstract

Rectifiers are generally categorized as passive and active rectifiers. Compared to the active rectifiers (e.g. pulse width modulated (PWM) rectifiers), passive rectifiers (i.e., diode rectifiers) result in higher total harmonic distortion (THD) in the input current. However, passive rectifiers are simpler than the active rectifiers in their hardware and control structure. Therefore, passive rectifiers are still considered with different THD minimization schemes. In industry, three-phase diode rectifiers are used in 6-pulse, 12-pulse, 18-pulse, and 24-pulse configurations with THD values of 30%, 15%, 10%, and 6%, respectively. Single-phase diode rectifiers result in a higher THD of 48%. Minimization of THD for single-phase rectifiers is a conspicuous need for increasing DC appliances for domestic use. This paper proposes a novel rectifier using a conventional diode bridge followed by a series chopper. A controlled conduction angle of the chopper significantly reduces the THD from 48 to 28%. The THD is further reduced to 16.4% on the primary side of the distribution transformer after the elimination of triple-n harmonics in a balanced configuration. The proposed topology uses a single switch operating at the line frequency making the circuit and control much simpler than a PWM rectifier, and the dynamic power loss is also low. So, the proposed topology is better suited for single-phase applications requiring circuit and control simpler than a PWM rectifier, and THD much lower than a conventional diode bridge rectifier. A comprehensive analytical analysis, circuit simulations, power loss analysis, and experimental results are presented for the proposed topology to validate its working and evaluate its performance.