Wenderoth, Lind & Ponack, LLP.
AC voltage regulator
 An AC voltage regulator, which not only has a fast response speed with respect to input voltage fluctuations but also is small in size and light in weight and is capable to boost an input voltage, comprises a high-frequency transformer 4, a first bi-directional semiconductor switch circuit 3, a second bi-directional semiconductor switch circuit 5 and a third bi-directional semiconductor switch circuit 6; an input AC voltage is ring-modulated by the first bi-directional semiconductor switch circuit 3 and the obtained ring-modulated voltage is transformed at a high frequency by the high-frequency transformer 4 and then demodulated by the second bi-directional semiconductor switch circuit 5, and the obtained AC demodulated voltage is added to the input AC voltage to produce an AC raised voltage, and the AC raised voltage is pulse width modulated by the third bi-directional semiconductor switch circuit 6, which is controlled to become ON only while the second bi-directional semiconductor switch circuit 5 is OFF, and the AC raised voltage is continuously regulated by continuous regulation of a duty ratio D of the second bi-directional semiconductor switch circuit 6 in the pulse width modulation. 
I-Hits Laboratory Chiyoda Corporation
H
H02M
inventional
Yasunobu Isao
Suzuki Sugawara