基于相位叠加原理的有源滤波器谐波指令新算法及控制

A novel approach to extracting harmonic instruction and its control of the active power filter based on phase superposition theory

具有移相变压器的交交变频器运行中功率因数较低且产生丰富的谐波,采用多套并联型有源滤波器分别在变压器各套移相副边进行有源滤波和无功补偿。在瞬时无功功率算法的基础上利用移相变压器副边谐波在原边可以叠加的特点,提出将变压器各副边谐波指令叠加的算法推算原边需要补偿的谐波指令,剔除掉在变压器原边通过反相位叠加而抵消的副边某些谐波分量,不必再在副边用有源电力滤波器补偿它们,从而减小了补偿容量。同时,在逆变器出线串联电容以降低有源滤波器直流侧电容工作电压。PSCAD/EMTDC软件仿真结果证实了新算法和降压控制的正确性。

The AC to AC frequency converter which contains phase-shiftng transformer has a low power factor and produces rich harmonics in operation, the harmonics and reactive power are compensated respectively from the secondary phase-shifting windings by several shunt APF （active power filter） in practical projects. Taking advantage of the harmonics in the secondary side of the transformer can be counteracted in the primary side,this paper introduces harmonics superposition algorithm to add the transformer secondary harmonic instructions together and calculates the primary harmonics instruction on the basis of instantaneous reactive power theory, so as to omit the harmonics which can be counteracted and avoid the compensation in the secondary side by APF,which reduces compensation capacitance. Meanwhile, series capacitor in the inverter outline can decrease DC side capacitor voltage of the active power filter. The simulation results of PSCAD/EMTDC software have justified the new algorithm and voltage depressing control.