How to calculate position error caused by resolver imperfection which results in transformation ratio variation for the SIN and COS channels ?
It should be noted that transormation ratio variation between the channels results in amplitude mismatch issue. Amplitude mismatch leads to the positional error which depends on the mismatch magnitude and actual sensor position. Equation (1) indicates relation between the error, position and mismatch.
error = Alfa/2 * sin(2*Theta), where Alfa is amplitude mismatch in percentage, Theta is rotor angle.
As can be seen the error oscillates at twice the rate of rotation while a maximum error of Alfa/2 is reached at odd integer multiples of 45 deg.
Please be aware that 0.3 % mismatch translates to 1LSB error for 12 bit converter.
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