Current THD and Output Voltage Ripple Characteristics of Flyback PFC Converters with LED Lamp and Nonlinear RL Loads

This study analysed the characteristics of total harmonic distortion (THD) and output voltage ripple in a flyback PFC converter circuit under two different loads, which are the LED lamp modules and nonlinear RL loads. The converter was designed to step down the AC input voltage (90 V-265 V) to a DC output voltage of 80 V DC for both loads, each with an output power of 16 W. The main objectives were to observe and assess current THD and output voltage ripple for both loads using two different capacitances of the output capacitor, which are 2400 μF and 6 μF, respectively. The results demonstrated that using smaller capacitors (6 μF), it increased output voltage ripple, which it increased for the LED lamp load from 10% to 25% and for the nonlinear RL load it increased from 15% to 70%. However, with the same smaller capacitors (6 μF), it reduced current THD for both loads, which for the LED lamp load it reduced from 12% to 10.3%, and for the nonlinear RL load it reduced from 13.7% to 8.3%. From these results, with 2400 μF of the output capacitor, it provided better performance in terms of current THD and output voltage ripple for both load types.

Current THD and Output Voltage Ripple Characteristics of Flyback PFC Converters with LED Lamp and Nonlinear RL Loads

This study analysed the characteristics of total harmonic distortion (THD) and output voltage ripple in a flyback PFC converter circuit under two different loads, which are the LED lamp modules and nonlinear RL loads. The converter was designed to step down the AC input voltage (90 V-265 V) to a DC output voltage of 80 V DC for both loads, each with an output power of 16 W. The main objectives were to observe and assess current THD and output voltage ripple for both loads using two different capacitances of the output capacitor, which are 2400 μF and 6 μF, respectively. The results demonstrated that using smaller capacitors (6 μF), it increased output voltage ripple, which it increased for the LED lamp load from 10% to 25% and for the nonlinear RL load it increased from 15% to 70%. However, with the same smaller capacitors (6 μF), it reduced current THD for both loads, which for the LED lamp load it reduced from 12% to 10.3%, and for the nonlinear RL load it reduced from 13.7% to 8.3%. From these results, with 2400 μF of the output capacitor, it provided better performance in terms of current THD and output voltage ripple for both load types.

Improvement of Single-Switch Bridgeless PFC Cuk Converter for Circulating Current Elimination and Components Maximum Current Stress Reduction

This paper presents the improvement of a single-switch bridgeless PFC Cuk converter for circulating current elimination and maximum current stress reduction on components. Circulating current is eliminated by rearranging the position of input diodes thus the input diodes can block the returning path of current through the input inductors. The principle of circulating current elimination is also discussed in detail in this paper. A 100 W converter with an output voltage of -48 V has been tested to verify the principle. The results of the experimental hardware show the removal of the circulating current, the maximum current stress in input diodes is reduced from 8 A to 2.8 A and the maximum current stress in input capacitors also reduced from 11 A to 9.8 A

Improvement of Single-Switch Bridgeless PFC Cuk Converter for Circulating Current Elimination and Components Maximum Current Stress Reduction

This paper presents the improvement of a single-switch bridgeless PFC Cuk converter for circulating current elimination and maximum current stress reduction on components. Circulating current is eliminated by rearranging the position of input diodes thus the input diodes can block the returning path of current through the input inductors. The principle of circulating current elimination is also discussed in detail in this paper. A 100 W converter with an output voltage of -48 V has been tested to verify the principle. The results of the experimental hardware show the removal of the circulating current, the maximum current stress in input diodes is reduced from 8 A to 2.8 A and the maximum current stress in input capacitors also reduced from 11 A to 9.8 A