| 摘要 |
<p>1,053,087. Inverting; frequency changing. BROWN, BOVERI & CO. Ltd. May 24, 1965 [May 26, 1964; June 26, 1964], No. 21826/65. Heading H2F. A frequency changer has a three-phase uncontrolled rectifier (not shown) supplying a frequency controlled three-phase inverter (thyristors 1 to 6, Fig. 1) which has a commutating controlled rectifier, such as 10, connected through commutating capacitors 12, 14, 16 to controlled rectifiers 2, 4, 6 of different phases. The commutating controlled rectifier is itself commutated by the capacitor 20 (which preferably has twice the capacitance of capacitors 12, 14, 16) when the next main controlled rectifier is fired. The control circuits may be arranged so that each main controlled rectifier conducts for a fixed time, whatever the frequency, making the converter suitable for driving a motor. No converter transformer is needed in this case.</p> |
