Toshiba T90S3S08KS6XSN, Manual

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TOSHIBA G9000 UPS White Paper
© 2008 TOSHIBA INTERNATIONAL CORPORATION – INDUSTRIAL DIVISION Page 5
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UPSG9000WP081201
synthesize the line-to-line output voltage increases as well. Consider the
circuit shown in Figure 6. Pattern of the line-to-line voltage (Table 2) shows
nine possible combinations and five resulting voltage levels (+E, +E/2, 0,
-E/2 and –E Volts). A train of variable-width pulses for a 3-level power
processor is shown in Figure 7. The resulting output waveform tracks the
sinusoidal much better than in the case of the conventional inverter.
E E
2 2
E E
2 2
E E
2 2
E E
2 2
E E
2 2
E E
2 2
E E
2 2
E E
2 2
- - 0
- - 0
- + - E
- + 0
0 0 0
+ - 0
+ - E
+ + 0
Terminal
U
Terminal
V
Line-to-
Line
Voltage
(U - V)
+ + 0
FIGURE 6
Equivalent circuit of
a multilevel (3-level)
3-phase inverter
circuit
TABLE 2
Pattern of the
line-to-line output
voltage for a 3-level
inverter