Feedforward Delta Modulation for Power Converters

The objective of this paper is to propose a feedforward delta modulation (FDM) control for switching-mode power converters. The operation principle and mathematical derivation for both the conventional delta modulation (CDM) and the FDM are presented. The proposed FDM uses the control signal to generate the variable integrating slope to obtain better control ability. By comparing to the CDM, the proposed FDM can improve the performance of the dc-ac inverter. The advantages include the following features: 1) wider switching frequency range with smaller electromagnetic interference; 2) larger fundamental component with less harmonics; 3) higher duty-ratio linearity; and 4) elimination of asymmetrical operation. In addition, the proposed FDM can be applied to the dc-dc converter, which cannot be done by using the CDM. It can achieve the fast transient response with voltage-mode control. The FDM controller design strategy for the dc-dc converter is given in this paper, followed by a design example. Finally, experimental results are shown to verify the performance of the proposed FDM for both the dc-dc inverter and the dc-dc converter.