| 摘要 |
A controller for controlling currents in an AC line connected to the controller is capable of causing the controlled current to assume any pre-determined magnitude and wave form. The pre-determined AC magnitude and wave form need not be of the same frequency or wave form existing at AC power lines connected to the controller. The controller uses the voltage at the AC power lines and an additional DC voltage as two sources of power to control the current in an inductor connected in series with the AC lines. A plurality of electronic switches are arranged so that at any instant in time, closing of appropriate switches will apply either the line voltage, or the sum of the line voltage and the DC voltage, or the difference between the line voltage and the DC voltage to the inductor. This causes the current of the inductor to increase or decrease at a rate determined by the net applied voltage. Because of the two sources of power, either a positive or negative voltage is available at any time for connection to the inductor. Modulation of the switches provides a time varying average voltage across the inductor that results in the desired time varying inductor current which, due to its series connection is also the AC line current. Applications of the controller include control of power factor, at unity or any desired lagging or leading level, neutralizing of harmonic line currents, and recovery of power generating externally of the controller by feeding regenerative current back to the AC power lines.
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