Nonlinear PI-control approach for improving the DC link voltage control performance of a power factor corrected system

Abstract

When fast voltage control is used in a power factor control, the ripple of the DC link causes current harmonics. This paper proposes a method to reduce the harmonic content of a fast voltage loop in a power factor correction (PFC) which can both produce low distortion during steady state operation and fast recovery from a load transient. The performance is achieved by using a Takagi- Sugeno (T-S) type nonlinear controller for DC link voltage control. The proposed nonlinear control is compared with linear PI control, which is tuned to meet the standardized regulations for harmonic content in a 3 kW single phase power supply. The results show that the presented nonlinear voltage controller can maintain the dynamic performance of the linear control with reduced current harmonics. It is also shown that the used nonlinear control method requires only marginally more complex control.