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Maximum Power Point Trackers (MPPTs) are power electronic conditioners used in photovoltaic (PV) system to ensure that PV structures feed maximum power for the given ambient temperature and sun's irradiation. When the PV panels are shaded by a fraction due to any environment hindrances then, conventional MPPT trackers may fail in tracking the appropriate peak power as there will be multi power peaks. In this work, a shuffled frog leap algorithm (SFLA) is proposed and it successfully identifies the global maximum power point among other local maxima. The SFLA MPPT is compared with a wellentrenched conventional perturb and observe (P&O) MPPT algorithm and a global search particle swarm optimisation (PSO) MPPT. The simulation results reveal that the proposed algorithm is highly advantageous than P&O, as it tracks nearly 30% more power for a given shading pattern. The credible nature of the proposed SFLA is ensured when it outplays PSO MPPT in convergence. The whole system is realised in MATLAB/Simulink environment.

Induction heating (IH) applications aided by power electronic control system have become very attractive in the recent past. The power electronics circuits succumb to severe switching loss, lower power density if proper switching methodology is not adhered. A state of uncertainty is indispensable in IH application as the power required by the load varies depending upon the nature of work piece. This uncertain issue makes the selection of the control algorithm and controller very vital. The mundane controllers may not be compatible to combat the uncertainties and leads to exhibit dynamic problems say transients, peak overshoot and poor response. Henceforth, the IH system requires a superlative converter topology and control scheme in order to have reduced switching loss and to improve the system performance there by negating the uncertainties. Here, in this work, a direct AC–AC boost resonant converter fed by pulse density modulation (PDM) is realized in a single stage mode. A fuzzy logic-based PDM control technique improves the efficiency and provides the versatile power control with reduced time domain specifications for dynamic changes in load. The proposed system has been studied using MATLAB/SIMULINK and validated using a hardware prototype employing dsPIC30F4011 microcontroller. The results reveal that efficient control over power can be accomplished by varying the density of the switching pulses, and thereby the efficiency is enhanced even with reduced component count. Also, the single-stage conversion is effective than its two-stage counterpart.

In the current scenario, power electronic device-based induction heating (IH) technologies are widely employed in domestic cooking, industrial melting and medical applications. These IH applications are designed using different converter topologies, modulation and control techniques. This review article mainly focuses on the modelling of half-bridge series resonant inverter, electrical and thermal model of IH load. This review also analyses the performance of the converter topologies based on the power conversion stages, switching frequency, power rating, power density, control range, modulation techniques, load handling capacity and efficiency. Moreover, this paper provides insight into the future of IH application, with respect to the adaptation of wide band-gap power semiconductor materials, multi-output topologies, variable-frequency control schemes with minimum losses and filters designed to improve source-side power factor. With the identified research gap in the literature, an attempt has also been made to develop a new hybrid modulation technique, to achieve a wide range of power control with high efficiency. A 100 W full-bridge inverter prototype is realised both in simulation and hardware, with various modulation schemes using a PIC16F877A microcontroller. The results are compared with existing techniques and the comparisons reveal that the proposed scheme is highly viable and effective for the rendered applications.

The concept of induction heating is slowly entrenching as it has the traits of homogeneous heating, zero pollution and higher power density. To achieve these traits convincingly in reality, there is a need to develop energy efficient converter topologies, which aid in achieving power regulation of soft switching and very high frequency operation. This paper presents the salient features of converter topologies used for domestic and industrial heating applications with a focus on its stage-wise power conversion, power density, load handling capacity, soft switching, reliability and size. The performance of these topologies is analysed in terms of converter switching frequency, power rating, modulation techniques, flicker, user performance and efficiency. Moreover, this review paper predicts the future trends associated with the adaptation of wide band-gap power semiconductor materials, multi-output topologies, variable frequency control scheme with minimum losses and filter design to improve source-side power factor. The detailed technology review will be extremely useful for researchers, designers and engineers in choosing the appropriate topology for the chosen application.

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Summary Induction heating applications aided by power electronic control have become very attractive in the recent past. For cooking applications, power electronics circuits need to feed power to multi loads with a suitable control technique. The induction heating system requires a superlative converter topology and independent control to deliver power to multi loads. The main idea of this research work is to develop a dual‐frequency half‐bridge series resonant high‐frequency inverter feeding power for multi loads independently. A pulse density modulation (PDM) control technique is used to control the output power independently. The inverter simultaneously powers both loads with constant switching frequency. The proposed system is simulated in MATLAB/Simulink and thermal analysis is carried out in COMSOL multi‐physics software. A 1 kW prototype experimental set up is developed to feed power to dual load with the switching frequencies of 20 and 80 kHz for load 1 and load 2, respectively. The experimental results are provided to validate the system performance for various duty cycles of the PDM signal. The simulation and experimental results are in good agreement. The efficient power control is accomplished by varying the density of the switching pulses.

Abstract:In high frequency induction heating systems, the effective load parameters change during the different operating conditions. It is necessary to maintain constant input voltage to the induction heating load to improve the quality of the heating. The resonant based high frequency converter is generally used for these applications for the reduction of switching losses. The resonant condition is also affected during the variation in load parameters. The controller should provide a good voltage regulation with less response time and less overshoot during the loading conditions. In this paper, a load adaptive fuzzy logic control scheme is proposed to perform the voltage control of the high frequency inverter under variable load conditions. A frequency tracking control system is also employed for the inverter system using the phase lock loop. The phase lock loop ensures the resonant frequency operation of the inverter during the change in load parameters. The state space model of the system is discussed to study the inverter during different operating conditions. The fuzzy logic controller based closed loop control scheme is developed using the MATLAB simulation tool. The responses of the conventional and fuzzy logic controllers are studied for load voltage regulation and the effectiveness of the control schemes is verified. The dynamic behavior of the system is studied under no load and loaded conditions with the two controllers. The fuzzy based closed loop control scheme improves the dynamic response of the system compared to the conventional controller. The response of the induction heating system is validated with a hardware prototype. The results are presented in order to confirm the proposed control strategy.