Slow-Scale and Fast-Scale Instabilities in Voltage-Mode Controlled Full-Bridge Inverter

Abstract

This paper discusses the slow-scale and fast-scale instabilities of a voltagemode controlled full-bridge inverter which is widely used in AC power supply applications. The main results are illustrated by exact cycle-by-cycle simulations. It is shown that the slow-scale instability is a type of low-frequency instability which manifests itself as a Hopf-type low-frequency oscillation in the whole line cycle, whereas the fast-scale instability is a type of local instability which manifests itself as a period-doubling bifurcation in some intervals of a line cycle. An averaged model and an improved discrete-time model are used to theoretically analyze the slow-scale and fast-scale instabilities, respectively. Finally, experimental results are presented to verify the results from simulations and analysis. Our work has revealed more instabilities which are likely to occur in the inverter, and has provided a convenient means of predicting stability boundaries to facilitate the design of the inverter.

Relationship of fast‐scale and slow‐scale instabilities in switching circuit with multiple inputs

“…Later, Chen et al [28,29] found that these two dynamics do interact with each other for certain parameter choices, and they termed the previous phenomenon as 'coexisting bifurcation'. Interaction between fast-scale and slow-scale dynamics have also been reported in current-controlled or voltagecontrolled DC/AC inverters [30][31][32][33]. It is now clear that the instabilities of fast-scale and slow-scale dynamics and their interaction need to be studied in detail because it may help to understand the distortion in current and voltage waveforms observed in many power electronic systems and may provide useful information for circuit designers.…”

Analysis of Subharmonic Oscillation and Slope Compensation for a Differential Boost Inverter

“…These phenomena can significantly jeopardize the system performance and can cause serious consequences on its reliability. Therefore, understanding these nonlinear phenomena, their analysis, prediction and control have increasingly become of great concern of many researchers all over the world [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The major part of the analytical results on subharmonic oscillation in power electronics converters has been achieved for DC-DC converters [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40].…”

“…Using the quasi-static approximation, in [15] the slow-scale and fast-scale instabilities in a voltage-mode controlled H-bridge inverter are reported and analyzed using an averaged model and a discrete-time model respectively. It is well known that conventional averaged model cannot predict the fast-scale instability and for that the discrete-time model must be used.…”

Experimental verification of Hopf bifurcation in pulse‐width modulated inverter fed cage induction motor drive system

“…Equations (1)- (5) and (15) represent the whole model equations from which the dynamical behaviour of the stator voltage controlled IM drive system is analysed using a numerical algorithm written in MATLAB. These equations are then written in the following nonlinear, non-autonomous form asẋ…”

“…In the bifurcation study of power electronic systems, the terms fast-scale and slow-scale instability have been coined: the former refers to the instability that affects the dynamics at clock frequency, and the later refers to the generation of a slower frequency of oscillation. In any system, both of these instabilities have been shown to downgrade the overall system performance [14][15][16][17][18]. MATLAB/Simulink was used for simulating the PWM inverter fed cage IM drive system described in the foregoing section, using the differential equation solver ode45, with maximum step size of 1 μs and relative tolerance of 1 ms. For all other simulation configuration parameters, default settings were used.…”