Harmonic filter, it is one is used at filter to divide power system Zhong Mou or for many times the device of harmonic. About harmonic filter, also divide according to working principle to have original formula filter and passive type filter two kinds, both between having certain distinction.

 

Active filter, call active filter wave again. He is passed detect the harmonic in our system, generate actively next as equal as our harmonic size, the is used at quits harmonic wave with opposite foreword. To us systematic harmonic undertakes offsetting. Those who use is means of a kind of compensation. Active filter is equivalent to the signal generator of a high-power substantially, reach hardware construction and transducer are similar, the harmonic content of signal of basis radical wave, generation frequency and extent are equal, but phasic differ the harmonic of 180° in order to offset this harmonic. Active filter is OK filter is divided all sorts of harmonic, especially what electrified wire netting exists is low second harmonic, and can come true at the same time do not have merit compensation. Active filter uses power electronic parts, cost is higher, safeguard need a course to groom, cover an area of an area small, adjustable, filter wave effect is ideal. As the development of technology of electric power electron, its cost drops the space is larger, it is inevitable development trend.

 

 

Passive filter, also can be said to call passive type filter. Its principle is capacitance adds reactance to pass match, form low impedance to some harmonic, make this second harmonic all flow into filter, if a controller dominates return circuit of wave of filter of two Gao Cixie wave at the same time, must throw first low the filter wave loop of second harmonic, can magnify otherwise harmonic. Controller is not to have result power to be sampling signal commonly, real time is collected, real time sends signal. Present casting those who cut component to be used mostly is silicon controlled rectifier is cast cut, answer speed fast. Main filter is divided tall second harmonic, and be opposite base wave have certain loss, generally speaking, filter wave effect is better, right base the loss of wave is bigger also. Passive filter cost is low, safeguard simple, cover an area of an area bigger, adjustable scope is little.