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Control and stabilisation of the resonant converters are essential problems in power electronics. The conventional model of the dc–dc series resonant converter (SRC) is derived using the sinusoidal approximation and generalised averaging followed by linearisation about an operating point. This model involves considerable approximation and is not applicable for large variation of load and supply voltage. The authors have already proposed a direct piece-wise affine (DPWA) modelling and control approach for the SRC that operates above resonant frequency. However, the DPWA technique is not applicable to an SRC that operates below resonance because of the presence of harmonics. In this study, a dynamic voltage-controlled oscillator (VCO) is introduced, so that the overall system consisting of the proposed VCO following by the SRC is modelled as a PWA system. Then, a hybrid controller is designed in order to regulate the dc output voltage of the SRC operating below resonance. Also, the stability analysis of the closed-loop system is presented in the form of linear matrix inequalities. A prototype of the SRC is constructed and the proposed hybrid controller is implemented on a digital signal processor (DSP) core. The simulation and experimental results show the effectiveness of this modelling and control approach.

The control and stabilization of resonant converters are essential problems in power electronics. The conventional controller design and stability analysis for these converters are based on the linearized averaged model. Nevertheless, the state variables in resonant converters have large ac variations and the validity of the linearized average model is violated. Hence, using large signal and nonaveraged models are necessary for controller design and stability analysis. In this paper, a new hybrid controller is presented that is applicable to dc-dc series resonant converters and use neither averaging nor small signal approximation. The dc-dc resonant converters are inherently switched affine systems with constrained switching law. The proposed controller is based on the switched behavior of the converter and the concept of piecewise affine methodology. Moreover, it has switched inner and proportional-integral (PI) outer control loops and does not require a modulator. The large signal and closed loop stability analysis of the resonant converters is presented by a theorem. The minimum phase attribute of the control system is investigated by zero dynamic stability analysis. The proposed controller has less complexity in comparison to other suggested controllers and can be implemented using simple analog circuits. The simulation and experimental results show the effectiveness of the proposed method.

Single-phase power factor correction (PFC) converter circuits are non-linear systems due to the contribution of their multiplier. This non-linearity causes difficulties in analysis and design. Models that reduce the system to a linear system involve considerable approximation, and produce results that are susceptible to instability problems. In this paper a piecewise affine (PWA) system is introduced for describing the nonlinear averaged model. Then robust output feedback controllers are established in terms of the linear matrix inequality (LMI). Simulation and experiments results show the effectiveness of the proposed control method.

The subject of modeling and stability analysis of dc-dc resonant converters is still a challenge. The conventional large signal nonlinear model of the resonant converter is derived using the sinusoidal approximation and averaging followed by linearization about an operating point. Models obtained with such method involve considerable approximation, and produce results that are limited for higher performance designs. Therefore, it is essential to investigate the stability of the resonant converters using a more sophisticated model. Because of semiconductors switching, dc-dc resonant converters are intrinsically hybrid systems consist of discrete input and continuous states. The complexity of the stability analysis and controller design is increased when the system variables are a combination of discrete and continuous variables. In this paper a novel polyhedral piecewise affine modeling framework is proposed for series resonant converters that is effective for operating both above and below resonance and when the converter operates either in continuous or discontinuous conduction modes. This model has both continuous input and continuous states. Hence, control design will be simpler. A hybrid controller is designed for the series resonant converters and the stability of the closed loop system is guaranteed. Simulation results show the effectiveness of the approach.

Power factor correction rectifiers have nonlinear characteristics. Analysis and design is very difficult based on nonlinear models. Piecewise affine modeling is an approach for this purpose The main problem of piecewise affine modeling is complexity of models. In this paper, the optimal algorithm based on reinforcement learning is introduced for complexity reduction. Large signal models are obtained by introduced purposed algorithm. The purposed (new) algorithm is implemented on the boost power factor correction rectifier. Comparison of between optimal piecewise affine, conventional Piecewise affine, linear and nonlinear models is done by simulations.

Power factor correction rectifiers have nonlinear characteristics. Analysis and design is very difficult based on nonlinear models. Piecewise affine(PWA) modeling is an approach for this purpose and design of controllers is straight for PWA models. The conventional PWA modeling has spikes of control signals in switching instances. It will remove by fuzzy-PWA modeling. In this paper, the fuzzy-PWA is introduced for precise modeling. The new modeling method is implemented on the boost power factor correction rectifier. Comparison of between fuzzy-PWA, conventional Piecewise affine and nonlinear models is done by simulations.