Due to the two inductances, it is possible to control simultaneously the pairs of switches and S1-S3 S2-S4 with no dead time. If in the time intervals (D is duty cycle and is period), flows through i0 > 0 DT T i0 S1, D1, L1, Z and in the time intervals it flows through If the current will go through switches (1-D)T, Z, S2, D2, L1. i0 < 0, S3 and The uniform PWM control is thus used, as in the case of the DC converters, where is the switching S4. f=1/T frequency. The load impedance in Figure 1 is given by the equation: ,, (2) where is the frequency of the AC grid that feeds the converter. fm A. The resistive load case The equivalent circuits used for calculating the operation equations were obtained under the following simplified hypotheses: the passive components are ideal, the power devices are ideal switches, the voltage is v sinusoidal and remains constant for a period and the interference of the snubbers is neglected. T Figure 3(a) shows the equivalent circuit corresponding to the interval [0, and the equivalent circuit t ϵ DT], corresponding to the interval [DT, or [0,(1-D) is shown in Figure 3(b), from the switching period t ϵ T] t’ ϵ T] K. , (3) (4) When we integrate the equation system (4) in the initial conditions, (5) we obtain: (6)
Due to the two inductances, it is possible to control simultaneously the pairs of switches S1-S3 and S2-S4 with no dead time. If i0 > 0 in the DT time intervals (D is duty cycle and T is period), i0 flows through S1, D1, L1, Z and in the time intervals (1-D)T, it flows through Z, S2, D2, L1. If i0 < 0, the current will go through switches S3 and S4. The uniform PWM control is thus used, as in the case of the DC converters, where f=1/T is the switching frequency. The load impedance in Figure 1 is given by the equation: ,, (2) where fm is the frequency of the AC grid that feeds the converter. A. The resistive load case The equivalent circuits used for calculating the operation equations were obtained under the following simplified hypotheses: the passive components are ideal, the power devices are ideal switches, the voltage v is sinusoidal and remains constant for a period T and the interference of the snubbers is neglected. Figure 3(a) shows the equivalent circuit corresponding to the interval t ϵ [0, DT], and the equivalent circuit corresponding to the interval t ϵ [DT, T] or t’ ϵ [0,(1-D) T] is shown in Figure 3(b), from the switching period K. , (3) (4) When we integrate the equation system (4) in the initial conditions, (5) we obtain: (6)
Single-Phase%20Direct%20AC-AC%20v17.docx