We are using AD2S1210 for position sensing in motor control. When the high voltage pwms are off, the resolver works fine but when we start switching, we sometimes get various errors sometimes we do not get any error. This is probably due to high voltage switching noise. We are using the attached input circuitry. the cables for SIN, SINLO, COS, COSLO and excitation are twisted pairs and the cable is shielded all together. The cable shield is terminated to CHASSIS which is the inverter and motor housing (not connected to AGND). The excitation amplitude is 11Vpp and resolver transformer ratio is 0.286.
What might be the problem, what modifications should we make?