1 Introduction

Rectifiers, especially single-phase bridge controllable rectifier circuits, are important and widely used circuits in power electronics technology, not only in general industry, but also in other fields such as transportation, power systems, communication systems, energy systems, etc. Therefore, comparative analysis and research on the relevant parameters of single-phase bridge controllable rectifier circuits and the working conditions of loads with different properties have strong practical significance. It is not only an important part of theoretical learning of power electronic circuits, but also has a predictive and guiding role in practical engineering applications.

2 single-phase bridge semi controlled rectifier circuits

In Figure 1, VT1 and VT2 are trigger pulses with a phase difference of 180 degrees? The thyristor, VD1 and VD2 are rectifier diodes, which form a single-phase bridge half controlled rectifier circuit. Resistance R and inductance L are the loads. Assuming inductance L is large enough, i.e., ω L ≥ R, since the current in the inductance cannot suddenly change, it can be assumed that the load current remains constant throughout the entire steady-state operation process. Due to the characteristics of the bridge structure, as long as the thyristor is conducting, a forward voltage is always applied to the load, and the load current always flows in one direction. Therefore, the bridge half controlled rectifier circuit can only operate in the front quadrant. Because ω L ≥ R, regardless of the value of the control angle α, the change in the load current id is very small.