SPRUJ55D September 2023 – July 2025 AM263P2 , AM263P2-Q1 , AM263P4 , AM263P4-Q1
A Resolver is a type of rotary electrical transformer used for measuring degrees of rotation. The resolver is typically directly mounted to the shaft of an electric motor. A typical resolver consists of a rotary transformer (exciter winding) and two windings separated by 90 degrees on the stator.
Resolver-front-end systems take a PWM Signal from the Resolver to Digital converter subsystem and generate an excitation sinusoidal signal (typically 7 Vrms) which is applied on the excitation coil. Rotation of the motor modulates the excitation signal and causes a modulated sine and cosine output directly related to the mechanical angle of the rotor with respect to stator. This sine and cosine outputs are monitored on the coupled coils or outputs of the Resolver. Electrical Zero (EZ) of a Resolver is defined as the position of the rotor with respect to the stator at which there is minimum voltage amplitude across the Sine winding and the maximum voltage amplitude across the Cosine winding when the input winding is excited with the rated voltage.
The Resolver to Digital Converter(RDC) subsystem generates an excitation signal as a Sine modulated PWM signal and that signal interfaces to an external amplifier which extracts the Sine wave and excites the excitation coil of the resolver. The sine and cosine outputs from the coils of the resolver after proper voltage scaling using external amplifiers ,are input to the internal SAR ADCs of the Resolver to Digital converter subsystem. The Resolver to Digital converter subsystem reads the output of the ADCs, processes the incoming digital data, and estimates the angle of the rotor and the angular velocity. It also performs diagnostic checks.