| 摘要 |
The operation of power converters places shift and distortion reactive power on the main power system. The interference currents thus generated can be short-circuited by impedance circuits, but this measure is not always sufficient. It is therefore proposed according to the invention to connect a controlled feedback auxiliary converter (2) using fast-switching semiconductors in parallel to a converter (1) on the input side. The actual value of the current measured on the input side is fed in both converters (1, 2) to an adding device (7, 8) connected to a current regulator (9, 10) which is connected in turn to a control (11, 12) for the converters (1, 2). A reference current interfaced via a multiplier (14) with a reference sine wave (15) which is synchronised with the a.c. voltage applied to the converters (1, 2) is taken to the adding device (7) for converter (1). The difference between the actual and reference values at this converter (1) is taken to an inverter (16), the output signal of which is taken to the adding device (8) for the auxiliary converter (2) as a reference value. Unlike tuned impedance circuits, this arrangement not only impedes certain frequency components in the interference currents but also facilitates the compensation of any shape of curve through the high switching frequency of the auxiliary converter (2). |
