An equivalent model for single and three phase power rectifiers with active loads

We show that in active load rectifier case, superposition method can be used to construct a simpler model. Although such a rectifier is highly non-linear, the superposition method can be operated when dividing the cycle period into diode conduction and non-conduction intervals. The superposition operation over the active load rectifier provides two equivalent circuits: a circuit that contains only the power source and a circuit that contains only the active load (an AC current source as a common model of an active load). Since the former contains a passive load rectifier, we are left with the problem of analyzing a single-phase active load. Because an equivalent model for the single-phase active load contains only a current source in parallel to a resistor, the analysis complexity of the whole system is greatly reduced. In addition, we show that every rectifier model can be defined either as a Norton form, in which the load consists of a current source connected in parallel to the resistance-capacitance load, or as Thevenin form, in which the load consists of a voltage source connected in series to the resistance-capacitance load. Theoretical results are validated through simulations, which show a very high correlation when comparing the ordinary model parameters (such as input current THD) with the equivalent one. These findings can give us a simpler model for an active load rectifier investigation and an easier mathematical analyzing.