Search Results (18)

Induction heating technology plays a significant role in heating applications with its high efficiency, fast response, and precise control ability. Traditional resonant inverter-based systems face problems such as complexity, lack of flexibility, and low efficiency in multi-load situations. To overcome these issues, a new non-resonant full-bridge multiple-output inverter topology using silicon carbide (SiC) semiconductor devices is presented. While the system is simplified by eliminating resonant components, efficiency is increased thanks to SiC devices. In the study, a coil design methodology focusing on coil resistance and inductance is presented to optimize energy transfer and maximize system performance. Load-sensing and advanced frequency-modulation techniques are integrated to provide precise and independent power regulation in multi-loads. Thus, the efficiency of energy distribution and system robustness are increased. The proposed topology offers heating performance that provides homogeneous heat distribution. The developed prototype was proven to operate reliably with high efficiency under different load conditions and was suitably applied for domestic induction heating applications. An efficiency of 96.78% was achieved at a 50 kHz operating frequency and 2000 W power level. Full article

The accurate measurement of cooking vessel temperatures in induction hobs is crucial for ensuring optimal cooking performance and safety. To achieve this, improvements in existing measurement methods such as thermocouples, thermistors, and infrared (IR) temperature sensors are being explored. However, traditional IR sensors are sensitive to interference from the heated glass ceramic, severely affecting accuracy. This challenge is addressed by introducing a new sensor system with an optical filter designed to match the glass ceramic’s optical characteristics. The theoretical model presented here proposes the separation of the total radiation reaching the IR sensor into components emitted by the cooking vessel and the glass ceramic. However, the radiation component originating from the glass ceramic mentioned here is significantly higher than the radiation component of the cooking vessel, which creates difficulties in measuring the temperature of the cooking vessel. Simulations and real cooking experiments validate the model and demonstrate that the optic filter significantly increases the contribution of pot radiation to the sensor measurement. This causes a more accurate reflection of the actual cooking vessel temperature, leading to improved temperature control and enhanced cooking experiences in domestic induction hob appliances. This research contributes to the field by innovatively addressing challenges in real-time temperature control for induction cooking appliances. The elimination of pot dependence and improved accuracy have significant implications for cooking efficiency, safety and food quality. Full article

Rice (Oryza sativa L.) is one of the most significant staple foods worldwide. Carbohydrates, proteins, vitamins, and minerals are just a few of the many nutrients found in domesticated rice. Ensuring high and constant rice production is vital to facilitating human food supplies, as over three billion people around the globe rely on rice as their primary source of dietary intake. However, the world’s rice production and grain quality have drastically declined in recent years due to the challenges posed by global climate change and abiotic stress-related aspects, especially drought, heat, cold, salt, submergence, and heavy metal toxicity. Rice’s reduced photosynthetic efficiency results from insufficient stomatal conductance and natural damage to thylakoids and chloroplasts brought on by abiotic stressor-induced chlorosis and leaf wilting. Abiotic stress in rice farming can also cause complications with redox homeostasis, membrane peroxidation, lower seed germination, a drop in fresh and dry weight, necrosis, and tissue damage. Frequent stomatal movements, leaf rolling, generation of reactive oxygen radicals (RORs), antioxidant enzymes, induction of stress-responsive enzymes and protein-repair mechanisms, production of osmolytes, development of ion transporters, detoxifications, etc., are recorded as potent morphological, biochemical and physiological responses of rice plants under adverse abiotic stress. To develop cultivars that can withstand multiple abiotic challenges, it is necessary to understand the molecular and physiological mechanisms that contribute to the deterioration of rice quality under multiple abiotic stresses. The present review highlights the strategic defense mechanisms rice plants adopt to combat abiotic stressors that substantially affect the fundamental morphological, biochemical, and physiological mechanisms. Full article

This paper presents a comparative evaluation of wide-bandgap power semiconductor devices for domestic induction heating application, which is currently a serious alternative to traditional heating techniques. In the induction heating system, the power transferred to the output depends on the equivalent resistance of the load, and the resistance depends on the operating frequency. Due to the switching characteristics of wide-bandgap power semiconductor devices, an induction heating system can be operated at higher operating frequencies. In this study, SiC and Si semiconductor devices are used in the comparison. These devices are compared according to different evaluation issues such as the turn-off energy losses, turn-off times, current fall time, the power losses of the internal diodes, and the conduction voltage drops issues. To perform the proposed evaluation, the series-resonant half-bridge inverter, which is frequently used in state-of-the-art induction heating systems, has been selected. The device suitability in an induction heating system is analyzed with the help of a test circuit. A comparison is made in terms of criteria determined by using the selected switches in the experimental circuit, which is operated in the 200 W to 1800 W power range and 45 kHz to 125 kHz switching frequency range. System efficiency is measured as 97.3% when Si IGBT is used. In the case of using SiC cascode JFET, the efficiency of the system is increased up to 99%. Full article

The conventional heating system is inefficient as the major part of the heating coil lies out-side the vessel it is placed on. This research article proposes a new single-coil multi-tapped induction heating system. This novel induction heating system is facilitated by a half-bridge resonant converter controlled by zero-voltage switching (ZVS). The multi-tapping winding system ensures an effective heat transfer between the coil and the working vessel with the windings of the induction coil segmented to an equivalent size of the vessel. The pulse density modulation (PDM) scheme employed here as the control proves to be the most versatile one. The whole system is duly simulated for an 850 W IH setup in MATLAB Simulink and implemented as a hardware prototype using a half-bridge resonant converter. The control pulses are developed through the PDM in a PIC16F877A controller. The simulation and experimental results prove the credibility of the proposed induction heating (IH) scheme, and during heavy loading conditions, it outperforms the single-coil IH system by gaining an efficiency of 89.29% Full article

Phase change materials (PCM) have been widely used in Thermal Energy Storage (TES) Systems. Considering the energy efficiency and the use of domestic hot water, the melting temperature range of phase change materials is considered to be optimal in the range of 50–60 °C. The most commonly used is sodium acetate trihydrate-based phase change material, which has the advantages of high latent heat and low price, but its high supercooling, low thermal conductivity, and phase separation affect its application. Therefore, this paper used sodium acetate trihydrate, disodium hydrogen phosphate dodecahydrate (DSP), and expanded graphite (EG) as raw materials to prepare composite phase change materials (CPCM) and used physical disturbance to further improve their properties. Firstly, their thermophysical properties were investigated by the step cooling curve method, differential scanning calorimetry (DSC), and x-ray diffraction (XRD). Secondly, in order to further evaluate the effect of physical disturbance on CPCM crystallization, further experimental studies were carried out by adjusting the rotor mass and rotational speed. The experimental results showed that when 1.5 wt.% DSP, 1.5 wt.% EG and physical perturbation work together, the CPCM phase transition temperature is 56.7 °C, and the latent heat is as high as 258.98 kJ/kg. At this time, its thermal conductivity increased from 0.62 w/m·k to 1.1625 w/m·k, and its subcooling degree decreased from above 20 °C to less than 0.5 °C, and no phase separation occurred. The greater the disturbance momentum (the greater the rotor mass or the greater the rotational speed), the shorter the induction time, which is more conducive to the crystallization of CPCM. The results obtained in this paper are instructive for the preparation of efficient new CPCMs. Full article

In domestic induction heating applications, cookware can be considered an equivalent load in a series resistor–inductor–capacitor resonant converter. Therefore, the electrical parameters of an equivalent circuit change according to the cookware material, size and the cookware position on the heating coil. This study proposes an online estimation method for detecting the cookware status, determining the material and estimating the equivalent heating resistance of cookware on an induction heating cooker (IHC) for power control. The proposed method could turn off the circuit in abnormal situations such as low equivalent heating coverage rate or non-ferromagnetic cookware and adjust the power in normal situations. In the method, a half-bridge series resonant converter (HBSRC) generates two test patterns with three resonant voltage pulses to detect cookware every 10 ms, only the current feedback information is needed to avoid the calculation loads and times necessary for complex signal operations in software. To verify the proposed method, a digital signal processor based HBSRC with 1000 W was constructed. The maximum errors between the estimated and measured resistance and inductance were 7.14% and 2.91%, respectively. Moreover, power control in emulated user operation reveal that the proposed method and control system can effectively estimate load online to detect cookware status and determine whether to turn off or vary the heating power for an IHC. Full article

Induction heating (IH) is a process of heating the electrically conducting materials especially ferromagnetic materials with the help of electromagnetic induction through generating heat in an object by eddy currents. A well-entrenched way of IH is to design a heating system pertaining to the usage of ferromagnetic materials such as stainless steel, iron, etc., which restricts the end user’s choice of using utensils made of ferromagnetic only. This research article proposes a new scheme of induction heating that is equally effective for heating ferromagnetic and non-ferromagnetic materials such as aluminium and copper. This is achieved by having a competent IH system that embodies a series resonant inverter and controller where a competent flexible load modulation (FLM) is deployed. FLM facilitates change in operating frequency in accordance with the type of material chosen for heating. The recent attempts by researchers on all metal IH have not addressed much on the variable shapes and sizes of the material, whereas this research attempts to address that issue as well. The proposed induction heating system is verified for a 2 kW system and is compatible with both industrial and domestic applications. Full article

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. Full article

The induction heating process at a domestic level is getting attention nowadays as this power converting topology ensures clean, reliable, flexible, and fast operation. The low input frequency is converted to required regulated high output frequency with indirect and direct power converting approaches. The circuit and control complexity and high conversion losses associated with indirect power converting approaches lower their uses for domestic induction systems. The direct ac-ac power conversion approach is one of the viable solutions for low and medium power level loads, especially for domestic induction heating loads. The circuit complexity, cost, and conversion losses of the direct power converting systems depend on the number of the controlled switching devices as each controlled switch requires one gate driving circuit and one isolated dc supply. Simplified pulse width modulation (PWM) switching control also lower their control effort. Therefore, in this article, a simplified direct ac-ac power converting approach is introduced for a high-frequency domestic induction heating system. Here, the regulation of the high output frequency is achieved by simply cascading the single-phase full-bridge rectifier with a full-bridge inverter with a simple control strategy. The characteristics of the developed topology are validated through simulation results of the Simulink-based platform and practical results of the developed practical setup. Full article

New semiconductor technology is enabling the design of more reliable and high-performance power converters. In particular, wide bandgap (WBG) silicon carbide (SiC) and gallium nitride (GaN) technologies provide faster switching times, higher operating temperature, and higher blocking voltage. Recently, high-voltage GaN devices have opened the design window to new applications with high performance and cost-effective implementation. However, one of the main drawbacks is that these devices require accurate base current control to ensure safe and efficient operation. As a consequence, the base drive circuit becomes more complex and the final efficiency is decreased. This paper presents an improved gate driver circuit for GaN devices based on the use of a constant current regulator (CCR). The proposed circuit achieves constant current regardless of the operating conditions, solving variations with temperature, aging and operating conditions that may degrade the converter performance. Besides, the proposed circuit is reliable and cost-effective, being applicable to a wide range of commercial, industrial and automotive applications. In this paper, its application to a zero-voltage switching resonant inverter for domestic induction heating was performed to prove the feasibility of this concept. Full article

The ongoing diffusion of solid-state DC/DC converters makes possible a partial migration of electric power systems from the present AC paradigm to a future DC scenario. In addition, the power demand in the domestic environment is expected to grow considerably, for example, due to the progressive diffusion of electric vehicles, induction cooking and heat pumps. To face this evolution, the paper introduces a novel electric topology for a hybrid AC/DC smart house, based on the solid-state transformer technology. The electric scheme, voltage levels and converters types are thoroughly discussed to better integrate the spread of electric appliances, which are frequently based on internal DC buses, within the present AC distribution networks. Voltage levels are determined to guarantee high safety zones with negligible electric risk in the most exposed areas of the house. At the same time, the developed control schemes assure high power quality (voltage stability in the case of both load variations and network perturbations), manage power flows and local resources according to ancillary services requirements and increase the domestic network overall efficiency. Dynamic simulations are performed, making use of DIgSILENT PowerFactory software, to demonstrate the feasibility of the proposed distribution scheme for next-generation smart houses under different operating conditions. Full article

Induction heating (IH) is an environmentally friendly solution for heating and melting processes. The required high-frequency magnetic field is accomplished through frequency controllers. Direct frequency controllers (DFC) are preferred to dual converters as they have low conversion losses, compact size, and simple circuit arrangement due to low component count. Numerous frequency controllers with complex switching algorithms are employed in the induction heating process. They have a complicated circuit arrangement, and complex control as their switching sequences have to synchronize with source voltage that requires the zero-crossing detection of the input voltage. They also have a shoot-through problem and poor power quality. Therefore, this research proposes a novel frequency controller with a low count of six controlled switching devices without a zero-crossing detector (ZCD) having a simple control arrangement. The required switching signals are simply generated by using any pulse-width-modulated (PWM) generator. The performance of the proposed topology is verified through simulation results obtained using the MATLAB/Simulink environment and experimental setup. Full article

The energy consumption used for domestic purposes in Europe is, to a considerable extent, due to heating and cooling. This energy is produced mostly by burning fossil fuels, which has a high negative environmental impact. The characteristics of a building are an important factor to determine the necessities of heating and cooling loads. Therefore, the study of the relevant characteristics of the buildings, regarding the heating and cooling needed to maintain comfortable indoor air conditions, could be very useful in order to design and construct energy-efficient buildings. In previous studies, different machine-learning approaches have been used to predict heating and cooling loads from the set of variables: relative compactness, surface area, wall area, roof area, overall height, orientation, glazing area and glazing area distribution. However, none of these methods are based on fuzzy logic. In this research, we study two fuzzy logic approaches, i.e., fuzzy inductive reasoning (FIR) and adaptive neuro fuzzy inference system (ANFIS), to deal with the same problem. Fuzzy approaches obtain very good results, outperforming all the methods described in previous studies except one. In this work, we also study the feature selection process of FIR methodology as a pre-processing tool to select the more relevant variables before the use of any predictive modelling methodology. It is proven that FIR feature selection provides interesting insights into the main building variables causally related to heating and cooling loads. This allows better decision making and design strategies, since accurate cooling and heating load estimations and correct identification of parameters that affect building energy demands are of high importance to optimize building designs and equipment specifications. Full article

Peas (Pisum sativum L.) belong among the world’s oldest domesticated crops, serving as a source of proteins, complex carbohydrates, vitamins and minerals. Autumn sowing allows a higher biomass production as well as the avoidance of the drought and heat stresses of late spring. However, the character of European continental winters limits plant growth and development through cold stress. This work sought parameters that reflect the cold tolerance of pea plants and consequently to suggest an afila-type pea cultivar with resilience to European continental winters. For this purpose, we employed indoor remote sensing technology and compared the 22-day-long acclimation to 5 °C of four pea cultivars: Arkta, with normal leaves and the known highest cold resistance to European continental winters, and Enduro, Terno and CDC Le Roy, all of the afila type. Besides evaluation of shoot growth rate and quenching analysis of chlorophyll fluorescence (ChlF) by imaging methods, we measured the chlorophyll content and ChlF induction with a nonimaging fluorometer. Here we show that the acclimation to cold of the Arkta exhibits a different pattern than the other cultivars. Arkta showed the fastest retardation of photosynthesis and shoot growth, which might be part of its winter survival strategy. Terno, on the other hand, showed sustained photosynthetic performance and growth, which might be an advantageous strategy for spring. Surprisingly, Enduro showed sustained photosynthesis in the stipules, which transferred and acclimated to 5 °C (cold-acclimated). However, of all the cultivars, Enduro had the strongest inhibition of photosynthesis in new stipules that developed after the transition to cold (cold-developed). We conclude that the parameters of ChlF spatial imaging calculated as averages from whole plants are suboptimal for the characterization of various cold acclimation strategies. The most marked changes were obtained when the new cold-developed leaves were analyzed separately from the rest of the plant. Full article