How do I set up the SINAMICS S120 as a tunable voltage source?

Question:

How to set the SINAMICS S120 as a power supply with independent voltage and frequency adjustment?

Answer:

In VECTOR mode, the output frequency and output voltage of S120 converter can be independently adjusted by setting the parameter P1300=19.

P1330 allows you to set the output voltage percentage. The reference voltage is P2001

The percentage of output frequency can be set for P1070, and the reference frequency is 50Hz

In V/f mode, the output voltage of the converter will be increased by default. You can set the parameter P1310=0 to eliminate the effect of voltage boost.

When P2001=1000V, P1310=0, P1300=19, P1330=10% (i.e., the set voltage is 100V) and P1070=10% (i.e., the set frequency is 5Hz), the frequency converter is started, and the output voltage and frequency curves are obtained as follows.

Figure 1 Output voltage and frequency curve of frequency converter

Explanation:

① Due to the function of slope function generator RFG, the output frequency will rise or fall along the slope with time. You can set P1120=0s and P1121=0s to eliminate the effect of RFG.

② Only after the induction motor excitation is completed, the output frequency begins to increase. The parameters P0346=0.001s and P0347=0s can be set to eliminate the influence of excitation time.

③ When the converter stops, it will judge whether to block the output according to the set frequency and the actual frequency. The parameter P1226=0 can be set to ensure that the output frequency drops to zero along the slope.

(4) In addition, because the output side of the converter is PWM wave, the harmonic content is large, the voltage peak is high, it needs to pay attention to when in use. If used as a power source, a sinusoidal filter and possibly a transformer must be selected.