A novel stability criterion of AC power system with constant power load

Power electronic converters in AC power system, such as the boost rectifier, behave as constant power loads (CPLs), which have negative impedance characteristics at the input terminals. And this might cause system instability. In small-signal sense, the stability of the system including the CPL is determined by the source output impedance and the load input impedance (admittance). As a result, the stability criterion based on these impedances is an effective way to check the stability of system. This paper summarizes existing work and introduces our contribution on the stability criterions for AC power system. A novel stability criterion using the infinite-norm of the impedance (admittance) matrixes is proposed. Further, the conservatism of the proposed criterion was compared with the one of the existing criterions.