TABLE OF CONTENTS This chapter is dedicated to single-phase controlled rectifiers, which are used in a wide range of applications. As shown in Fig. 11.1, single-phase rectifiers can be classified into two big categories:
Topologies working with low switching frequency, also known as line commutated or phase controlled rectifiers.
Circuits working with high switching frequency, also known as power factor correctors (PFCs).
Line-commutated rectifiers with diodes, covered in a previous chapter of this handbook, do not allow the control of power being converted from ac to dc. This control can be achieved with the use of thyristors. These controlled rectifiers are addressed in the first part of this chapter.
In the last years, increasing attention has been paid to the control of current harmonics present at the input side of the rectifiers, originating from a very important development in the so-called PFC. These circuits use power transistors working with high switching frequency to improve the waveform quality of the input current, increasing the power factor. High power factor rectifiers can be classified in regenerative and non-regenerative topologies and they are covered in the second part of this chapter.
The single-phase half-wave rectifier uses a single thyristor to control the load voltage as shown in Fig. 11.2. The thyristor will conduct, on-state, when the voltage v T
