Analysing The Stability Of The Non-Linear Electronic Networks Using The Power Balance Principle

The stability theory of the power system is introduced to the electronic information knowledge in this paper. The power balance should be ensured to keep the cycle oscillation, and the electronic networks that can't maintain self-excited oscillation should be certain steady.The reactive power is usually ignored while judging the stability of non-linear electronic networks. The power balance is combined with nonlinear differential equation. The fundamental-wave balance principle is utilized to overcome the difficulty of solving nonlinear differential equation in mathematical domain. For the electronic network described by Lienard Equation including variational damping term, the equivalent average value Df of energy contributed by the variational damping force in a cycle can be derived according to equivalent thrust theory. The fundamental-wave component of current inputting electronic network is acquired when sinusoidual excited voltage U is exerted to the proper port. In this paper, we will prove that the sign of D_f indicating network energy variation is opposite to the sign of input conductance G_i representing the active power inputting electronic network, while excited voltage U maintains sinusoid. The flow direction of active and reactive component of current inputting eletronic network decides the possiblity of the self-excited oscillation of network, when the excited source switched off. Hence, the signal value of input adimitance G_i and B_i becomes stability criterion of judging electronic networks. The existence and stability of the system limit cycle can be judged by the change trend of the D_fwith Um in a little zone near zero.