AD2S100

REV. A

–11–

VECTOR

COPROCESSOR

AD2S100

ADC

HOST COMPUTER

ADSP-2101/

ADSP-2105

DAC

AD2S80A

R/D

CONVERTER

AD7874

DAC-8412

VECTOR

COPROCESSOR

AD2S100

ia, ib, ic

θ

INDUCTION

MOTOR

INV

+

PWM

Figure 14. Advanced Motion Control Engine

The magnitude of the n-th harmonic as well as the fundamental

component in the power line is represented by the output of the

the AD2S100 homopolar output will indicate whether the

three phases are balanced or not. For more details about this

application, refer to the related application note listed in the

bibliography.

LOW PASS

FILTER

TRANSFORMATION

12-BIT UP/DOWN

COUNTER

AD2S100

HOMOPOLAR

OUTPUT

PULSE INPUTS

DIRECTION

Va

Vb

Vc

TWO-TO-THREE

CLARK

TRANSFORMATION

Vd

Vq

Figure 15. Harmonics Measurement Using AD2S100

MULTIPLE POLE MOTORS

For multi-pole motor applications where a single speed resolver

is used, the AD2S100 input has to be configured to match the

electrical cycle of the resolver with the phasing of the motor

windings. The input to the AD2S100 is the output of a resolver-

to-digital converter, e.g., AD2S80A series. The parallel output

of the converter needs to be multiplied by 2

n = the number of pole parts of the motor. In practice this is

implemented by shifting the parallel output of the converter left

relative to the number of pole pairs.

Figure 16 shows the generic configuration of the AD2S80A with

the AD2S100 for a motor with n pole pairs. The MSB of the

AD2S100 is connected to MSB-(n-1) bit of the AD2S80A digi-

tal output, MSB-1 bit to MSB-(n-2) bit, . . ., LSB bit to LSB

bit of AD2S80A, etc.

MSB

MSB-1

.

.

.

MSB – (n–1)

.

.

.

LSB + (n–1)

MSB

MSB-1

MSB-2

.

.

.

.

.

.

.

LSB

.

.

.

.

AD2S80A

AD2S100

12,14 OR 16-BIT RESOLUTION MODE

n = POLES

Figure 16. A General Consideration in Connecting R/D

Converter and AD2S100 for Multiple Pole Motors

Figure 17 shows the AD2S80A configured for use with a four

pole motor, where n = 2. Using the formula described the MSB

is shifted left once

AD2S80A

AD2S100

BIT1

BIT2

.

.

.

.

.

.

BIT13

BIT14

MSB

MSB-1

.

.

.

.

.

.

.

LSB

(MSB)

(LSB)

14-BIT RESOLUTION MODE

.

.

.

.

.

.

Figure 17. Connecting of R/D Converter AD2S80A and

AD2S100 for Four-Pole Motor Application