| 摘要 |
PROBLEM TO BE SOLVED: To satisfy power source higher harmonic restriction, to reduce the loss of a PWM converter and to save energy in an active filter controller where the current of the PWM converter is controlled so as to cancel higher harmonic current at a load side. SOLUTION: The controller is provided with a means for detecting instantaneous harmonic current at the load side by a current detecting equipment 11a so as to adopt it as a higher harmonic compensating current command ic*, a means 16 for detecting the sizes of fifth, seventh, eleventh and thirteenth higher harmonic current at a power source system side and the higher harmonic current restriction value setting means of respective ordinal numbers. A comparing means 17 successively reduce the amplitude of the higher harmonic compensating current command by changing compensation gain K within a range where a higher harmonic current detecting value at every ordinal number does not become more than a restriction value so as to execute an operation by weakening higher harmonic curren compensation. When the amplitude of the current command becomes zero, the comparing means 18 outputs an interrupting signal and a gate voltage to the PWM converter 3 is interrupted from an AND means 15. |
