Three-phase voltage source pulsewidth-modulated (PWM) rectifiers (VSRs) have received great attentions in industrial applications. Recently, some attempt has been made to study the flexible direct current (DC)-bus voltage regulation problem under dynamic load of three-phase VSRs by switched control. Several proportional-integral (PI) controllers are designed for different load resistance range while only one PI controller is implemented for a given time instant by regarding the load resistance as the switching law. However, the existing approach is based on state feedback control, which requires the measurement of source current and DC-bus voltage. In this paper, we will adopt an output feedback control scheme, i.e., only DC-bus voltage should be measured. Compared with the existing result, our design requires less information and reduces the cost. Moreover, the robustness analysis of plant parameters is given when all the states are available. Simulation results demonstrate the effectiveness of our design.