A General Frequency-Domain Model of Trailing-Edge and Leading-Edge Carrier PWM dc–dc Converter Based on Hybrid Continuous and Discrete-Time Descriptions

Abstract

This article proposes a general frequency-domain model to reflect the effect of trailing-edge and leading-edge carrier on the stability of the pulsewidth modulation (PWM) dc-dc converter. The state vector in the general state-space averaging (SSA) model is considered as the sampled value of the actual state vector rather than the average value. In this way, the continuous and discrete-time descriptions can be used together to maintain a balance between accuracy and simplicity. In the proposed model, the main circuit and controller are described by a continuous model with the same equations as the existing SSA model. Therefore, the simple structure of the continuous model is inherited. The PWM carrier comparison component is described by a discrete-time model (DTM), which can accurately reflect the effects of PWM carrier and state vector ripple. Thus, the high accuracy of DTM is maintained as well. In order to show the advantages of the proposed model, the comparison between the proposed model and other existing models is made. Compared with the SSA model and the discrete average model, the proposed hybrid model is more accurate. Compared to the DTM, the proposed hybrid model is more convenient to use. Simulation and experiment results verify the above analyses and advantages.