JPS6439520A - Resolver digital converting device - Google Patents

Abstract

PURPOSE:To follow up the signal of a resolver which rotates at a high speed by converting the output voltage of a subtracter from analog to digital by a tracking type resolver digital converting device, adding the value to a digital value, and varying plural digital values at a time. CONSTITUTION:The output (a) of the subtracter 4 is converted by an A/D converter 5 into a plural-bit digital (D) signal (b). A sign decision device 9 decides the sign of a reference signal (c), which is converted into the D signal (d) of 1 or 0. A selector 13 selects the D signal (b) and the output signal (e) of an inverter 6 according to the signal state of the decision device 9 and outputs a D signal (f). This D signal (b) corresponds to the difference between the angle thetaof a resolver R oscillator and an angle phi to a D value (i) (held temporarily in a register 8). An adder 7 adds the D signal (f) and D value (i) to calculate a new D value (h) and the new D value (i) is updated with an external clock (g). This operation is repeated and an error sin(theta-phi) is added to the D value (k) until theta=phi, thereby converting the R signal into the D value.