AD2S100

The AD2S100 performs the vector rotation of three-phase 120 degree or two-phase 90 degree sine and cosine signals by transferring these inputs into a new reference frame which is controlled by the digital input Ø. Two transforms are included in the AD2S100. The first is the Clarke transform which computes the sine and cosine orthogonal components of a three-phase input. These signals represent real and imaginary components which then form the input to the Park transform. The Park transform relates the angle of the input signals to a reference frame controlled by the digital input port. The digital input port is a 12-bit parallel binary representation.

If the input signals are represented by Vds and Vqs, respectively, where Vds and Vqs are the real and imaginary components, then the transformation can be described as follows:

Vds' = Vds CosØ – Vqs SinØ
Vqs' = Vds SinØ + Vqs CosØ

Where Vds' and Vqs' are the output of the Park transform and SinØ, and CosØ are the values internally derived by the AD2S100 from the binary digital data.

The input section of the device can be configured to accept either three-phase inputs, two-phase inputs of a three-phase system, or two 90 degree input signals. The homopolar output detects the imbalance of a three-phase input only. Under normal conditions, this output will be zero.

The digital input section will accept a resolution of up to 12 bits (AD2S100). An input data strobe signal is required to synchronize the position data and load this information into the device counters. A busy output is provided to identify the conversion status of the AD2S100. The busy period represents the conversion time of the vector rotation.

Two analog output formats are available. A two-phase rotated output facilitates multiple rotation blocks. Three phase format signals are available for use with a PWM inverter.