y电皿负栽单相交流调压电路在开通角为以时,负栽电压有效值Un、负 载电流有效值l、晶闸管电流有效值和电路的功率因数λ分别为 2U, sin ot d()=U-sin 2a+ 丌-a (4-1) 丌 丌 4-2) R √2 U, sin ot a sin la r dot= (4-3) 丌 R R 丌2丌 PU。。U T -a sin 2a+ (4-4 S UU 2丌 Power electronics 99 电阻负载单相交流调压电路在开通角为a时，负载电压有效值Uo、负 载电流有效值Io、晶闸管电流有效值IVT和电路的功率因数λ分别为 ( ) ( )   a a  w w   a − = = +  sin 2 2 1 2 sin d 1 1 2 Uo U1 t t U (4-1) ( ) ) 2 sin 2 (1 2 2 sin 1 2 1 1 2 1  a  a w w   a = − +         =  R U d t R U t I T (4-2)   a a   − = = = = sin 2 + 2 1 1 o 1 o o o U U U I U I S P (4-3) R U I o o = (4-4)