Minimisation of line current harmonics in single-phase AC-DC converter using a microcontroller

A microcontroller-based circuit topology for a single-stage single-phase AC-DC converter with line current harmonics minimisation properties is presented. The circuit is based on the half-controlled AC-DC converter circuit in which the active devices are two power MOSFET transistors. The switching action of the transistors controls the shape and hence the harmonic content of the supply current to the converter. The MOSFETs are switched by the same PWM signal which is generated internally by PIC microcontroller which reduces the circuit complexity. Results, obtained using a 600 W converter, indicate that the harmonics of the line current can be reduced to levels compliant with those required by relevant international harmonics standards.