Resolver-to-digital converters with the arctangent function transformation

The work is devoted to the peculiarities of the construction of amplitude converters of type “angle-parameter-code”, in which arctangent function transformation is used when converting output signals of a resolver into a digital equivalent of movement. The features of the construction of brushless classical resolvers and varieties of their variable reluctance, in Russia known as reductosin, are considered. It allows to realize an electrical reduction, at which the sensor accuracy increases considerably. The principle of operation of the resolver, output signals of which contain reliable information about components of displacement of the rotor, is found out. Resolver-to-Digital Converter (RDC) corresponds to the postulate of the general theory of relativity on communication of space and time. A special place among one-component “angle-parameter-code” converters is held by the structures using arctg-conversion, at which quadrant or octant range splitting of the transformation of angular displacement is used. In the first case, angular transformation is implemented by the digital signal processor (DSP) or microcontroller, and in the second one - by ROM with arctg insertion. The structure and ratios necessary for calculation of movement by software and tabular implementation of arctangent function transformation. An original version of the analog-to-digital converter with arctg ROM is presented. Its capacity at identical length of the output code is four times less than the capacity of traditionally used ROM with a sine-cosine firmware. Octant representation of a full range transformation of the angle of rotation allows to generate an additional high order digit of the output code in comparison with a traditional quadrant band splitting. This not only improves the resolution of the conversion twice, but also simplifies coordination of samples at application of an electrical reduction with the reductosin.