Modeling and analysis of 6 pulse rectifier used in HVDC link

This paper presents miniature hardware model of 6 pulse controlled rectifier circuit for a monopolar HVDC link. The Controlled rectifier is interfaced with PIC (16F72) microcontroller for generating various firing angles. The results of output voltage are recorded using digital oscilloscope and are compared with the theoretical values at different firing angles. Performance analysis parameters such as voltage ripple, ripple percentage, harmonics with and without low pass filter for R and RL load is obtained by varying the firing angle. Results show that the ripple factor and ripple percentage has drastically reduced with the addition of the low pass filter and also smoothens the DC output voltage which were observed in digital oscilloscope. There has been a reduction of 92% ripple for R load and 60% for RL load (for firing angle α= 90°).