Software-Based Resolver-to-Digital Converter Using an α-β-γ Filter

The software-based resolver-to-digital converter (RDC) is cost-effective and widely used to obtain an angular position. Angle estimation is an essential procedure in an RDC, but conventional angle estimation methods face difficulties in parameter tuning and lack analysis of the parameters. To overcome these problems, a novel angle estimation method based on an alpha-beta-gamma filter is proposed in this article, which only requires tuning one parameter. The performance measures to gauge the tracking ability, noise filtering strength, and transient response performance are derived. In addition, this article analyzes the impacts of nonideal characteristics when using the frequency-shifting technique. To suppress the impacts, an amplitude corrector is further proposed. Combined with the alpha-beta-gamma filter and the amplitude corrector, the proposed RDC has an excellent performance in terms of noise rejection, fast position response, and tracking ability. Experimental tests verify the effectiveness and feasibility of the proposed RDC system.