Why does the Voltage Measurement block in SimPowerSystems output a strange result when the Controlled Voltage Source is used in a Phasor Analysis simulation?

I have a model which uses an AC Voltage Source block to generate a 100V 60Hz signal. When I select 'Phasor Analysis' in the SimPowerSystems GUI, I can observe the signal using a Voltage Measurement Block and it appears to be correct. In the same model, I have a Controlled Voltage Source block with its input generated by a Simulink Sine Wave source block having the same magnitude and frequency parameters as the AC Voltage Source block. However, when I view the output of the Controlled Voltage Source using a Voltage Measurement Block it appears to be completely incorrect. Why is this occurring?

Answer 1

[MathWorks Support Team]

As soon as you check the Phasor Analysis simulation option, SimPowerSystems automatically converts the sine wave voltage specified in the AC Voltage Source block into a phasor signal (a complex signal in fact).

The problem is that, unlike the AC Voltage Source block, SimPowerSystems does not automatically convert the input signal of the Controlled Voltage Source block from a real signal into a complex signal. Instead the input signal (a real-valued sine wave signal in this case) is passed directly to the rest of the SimPowerSystems as if it were a complex number. This causes the signal displayed by the Voltage Measurement block to be different than expected.

As a result as soon as you switch to using Phasor Analysis, complex signals must be used to feed the Controlled Voltage Source or other controlled source blocks in order to produce the expected results.