Abstract:The Single-phase bridge loads are a typical residential load harmonic sources, whose current total harmonic distortion rate can be quite high. There are a large number of single-phase bridge loads widely distributing in the distribution network. Based on the generic circuit of the switching power supply, the parameters values of the basic circuit are solved through numerical iteration in the time domain. Then the frequency domain harmonic model, cross admittance matrix is derived, which transfers nonlinear characteristics of the Single-phase bridge loads in the time-domain to linear admittance matrices in the frequency-domain. Test results show that the output harmonic current of this model basically conforms to measurements and simulation results. So the model built by cross admittance matrix possesses high accuracy.