| 摘要 |
<p>PURPOSE:To control a two-phase double control type chopper merely by providing one main circuit current detector. CONSTITUTION:A detector 12 is passed through a current path flowing through a main smoothing reactor 13 and reversely passed through a current path flowing through a main smoothing reactor 14. Assume that currents flowing through the reactors 13, 14 are represented by I1, I2, the detector 12 produces an output 0 in case of I1 = I2, a positive output in case of I1>I2, and a negative output in case of I1<I2. The output of the detector 12 is applied to a logic circuit 17, which thereupon applied its output signal to logic circuits 18, 19 in accordance with the positive or negative of the output. When the output is positive, the circuit 19 produces a signal 20 for reducing the conductivity of first phase chopper 15, and when the output is negative, it produces a signal 21 for reducing the conductivity of the second phase chopper 16. It also produces a chopper off instruction 22 at predetermined time.</p> |
