Environmental Engineering Reference
In-Depth Information
impedance between the voltage reference and the terminal. The results from the R-inverters
with K i =
4 are provided for comparison.
19.7.2.1 With a Linear Load
Simulations were carried out for a linear load with R L =
. The results for the C-inverters
and R-inverters are shown in the left and right columns of Figure 19.14, respectively. The real
power and reactive power were well shared in both cases and the output voltage was very close
to the rated voltage. The THD of the output voltages in both cases was very low as well.
9
19.7.2.2 With a Non-linear Load
The same simulations were carried out for a full-bridge rectifier load with an LC filter L
=
150
. The results for C- and R-inverters are shown in the left
and right columns of Figure 19.15, respectively, with the steady-state performance shown in
Table 19.1. Again, both the C- and R-inverters performed very well: the real power and reactive
power were accurately shared and the output voltage was close to the rated voltage. The voltage
THD of the C-inverters was slightly better than that of the R-inverters, with considerably
reduced low-order harmonics. It is worth noting that although the output impedances of
the two inverters are the same, which means the per-unit output impedance is significantly
different, the inverters shared both the real power and the reactive power accurately.
μ
H , C
=
1000
μ
F and R L =
9
19.7.3 Experimental Results
Experiments were carried out on a test rig that consists of two single-phase inverters powered
by two separate 42 VDC voltage supplies. The parameters of the system are the same as those
given in the previous section. Experiments were carried out for C-inverters with C o =
479
μ
F
and R-inverters with K i =
4
.
19.7.3.1 With a Linear Load
Experiments were carried out for a linear load with R L =
. The results for C-inverters
and R-inverters are shown in the left and right columns of Figure 19.16, respectively, for
comparison. The system worked very well for both cases: with accurate sharing of real power
and reactive power, good regulation of output voltage and low THD. With comparison to
R-inverters, the voltage regulation performance is slightly better because this is related to
the reactive power of the load, which is small, and the frequency variation is slightly higher
because this is related to the real power.
9
19.7.3.2 With a Non-linear Load
The same experiments were carried out for a full-bridge rectifier load with an LC filter
L
. The results for C-inverters and R-inverters are
shown in the left and right columns of Figure 19.17, respectively. Again, the system worked
very well for both cases with accurate sharing of real power and reactive power and good
capability of voltage regulation. The C-inverters demonstrated much better THD than the
=
150
μ
H, C
=
1000
μ
F and R L =
9
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