Power Electronics and Motor Drive Systems

5.1. Single-Phase Full-Bridge Fully Controlled Thyristor Rectifier

The most well-known single-phase fully controlled rectifier, shown in Fig. 5.1(a), uses four thyristor devices. The dc load source E can be a battery bank or the counter electro motive force (EMF) of a dc motor. The operation of this rectifier can be described as follows: When during the first half-cycle a gating pulse is applied to thyristors Q₁ and Q₄, which are forward biased, they are turned on connecting the input power supply voltage to the load terminals. The equivalent circuit of the rectifier during this mode is shown in Fig. 5.1(c). During this mode the input voltage, which has positive values, generates a positive input and output current. When during the second half-cycle ...