| 摘要 |
In an uninterruptible power supply ("UPS") having a flywheel storage module, switched rectifying devices of an AC/DC converter of the UPS are walked in after a utility power outage by initially firing the switched rectifying devices at a phase angle where the voltage output by the AC/DC converter to a direct current bus matches a depleted DC bus voltage. In an aspect, the initial phase angle is determined by the equation: <maths id="MATH-US-00001" num="00001"> <math overflow="scroll"> <mrow> <mi>theta</mi> <mo>=</mo> <mrow> <mrow> <mn>180</mn> <mo></mo> <mstyle> <mspace width="0.6em" height="0.6ex"/> </mstyle> <mo></mo> <mi>deg</mi> </mrow> <mo>-</mo> <mrow> <mi>arcsin</mi> <mo></mo> <mrow> <mo>(</mo> <mfrac> <mi>VDC</mi> <mrow> <mi>VRMS</mi> <mo>*</mo> <msqrt> <mn>2</mn> </msqrt> </mrow> </mfrac> <mo>)</mo> </mrow> </mrow> </mrow> </mrow> </math> </maths> where theta is the initial phase angle, VDC is the depleted DC bus voltage and VRMS is the RMS voltage of the utility power.
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