MPPT based power control of resonant converter applied to induction cooktops

Resonant converters are well suited for induction heating (IH) applications due to their advantages such as efficiency and power density. The control systems of these appliances should provide smooth and wide power control with fewer losses. In this paper, a simple phase locked loop (PLL) based variable duty cycle (VDC) pulse density modulation (PDM) power control scheme for use in class-D inverters for IH loads is proposed. This VDC PDM control method provides a wide power control range. This control scheme also achieves stable and efficient Zero-Voltage-Switching (ZVS) operation over a wide load range. Analysis and modeling of an IH load is done to perform a time domain simulation. The design and output power analysis of a class-D inverter are done for both the conventional pulse width modulation (PWM) and the proposed PLL based VDC PDM methods. The control principles of the proposed method are described in detail. The validity of the proposed control scheme is verified through MATLAB simulations. The PLL loop maintains operation closer to the resonant frequency irrespective of variations in the load parameters. The proposed control scheme provides a linear output power variation to simplify the control logic. A prototype of the class-D inverter system is implemented to validate the simulation results.

The advantages of resonant power converters, such as high efficiency and high power density, make them a suitable solution for domestic applications such as induction heating (IH) cookers. The control systems of these appliances require performing accurate and smooth power control while assuring the safety of the power devices. In order to accomplish these tasks, it is necessary to have information about the target output power, which is selected by the user, and the specific parameters of the output current. In this paper, a single-bit second-order sigma-delta ( Σ-Δ) analog-to-digital converter (ADC) is proposed to measure the magnitude of interest in resonant power converters. An optimized digital low-pass filter architecture is proposed to extract the output current from the digitized bit stream. This filter improves the accuracy while having low logic-resource consumption. The proposed ADC has been verified using a resonant inverter applied to the IH cooktop application. The inverter switching frequency is in the range of 40-80 kHz. A statistical analysis of the final measurement system has been performed to assess the system accuracy. The proposed system achieves good accuracy in the inverter operating range.

Solar energy is abundantly available energy for the generation of heat, and one the best appliances used for this purpose is Induction heaters. For the heat generation application, the combination of solar energy with the induction heat generation technique is the productive solution. Due to high efficiency and high-power density, resonant converters with soft switching are commonly utilized in domestic induction heating applications. For induction heating applications, a low profile and an improved efficiency resonant inverter design and implementation procedure are presented. Reducing conduction losses by using automotive-grade MOSFET devices against the classical IGBT-based converter. Conversion efficiency can be increased by decreasing switching losses which can be done by reducing switching times of MOSFET devices. Heating the metallic pan with circulating eddy currents induced by a high-frequency AC magnetic field is the principle of the induction cooker. If the load has an electrically conducting base, then the coil within the induction cooker and the load (pan/pot) acts as a transformer. The power will be transferred with high efficiency if the conducting base is ferromagnetic. An efficient control scheme incorporated in class E resonance heating by using solar power is presented. The simulation analysis is done in MATLAB-SIMULINK. Index Terms: induction heating, solar energy, class E resonant converter, MOSFET, MATLAB-SIMULINK

This article proposes a triple-mode isolated resonant buck-boost converter over a wide input voltage range for residential applications of photovoltaic arrays and fuel cells. First, in case that the input voltage is smaller than the nominal voltage, it operates in a resonant-boost mode that boosts the input voltage by using a bridgeless structure on the secondary-side. Next, if the input voltage is within the range of the nominal voltage, it operates in a fully series-resonant mode, which results in high efficiency by the soft-switching on the primary-side switches and reduced conduction loss. Last, if the input voltage is more than the nominal voltage, it operates in a pulsewidth modulation series-resonant buck mode, which can achieve the step-down conversion by reducing the duty cycle. Unlike the conventional resonant converters, the proposed converter achieves high efficiency and less number of power components over a wide input voltage range. Finally, the performance of the proposed triple-mode isolated resonant converter has been fully verified on a prototype 400 W test-bed in the wide input voltage of 35-65 V.

LCL series resonant full bridge converter (SRFBC) is a new, high performance DC-DC converter. High frequency DC-DC resonant converters are widely used in many space and radar power supplies owing to their small size and light weight. The limitations of two element resonant topologies can be overcome by adding a third reactive element termed as modified series resonant converter (SRC). A three element resonant converter capable of driving voltage type and current type load with load independent operation is presented. These converters are analyzed by using the state space approach is presented. Pulse width modulation is employed to control and regulate the output voltage. The purpose of this paper is to study the performance of the three elements LCL series resonant full bridge converter with capacitive and inductive output filter under pulse width modulation keeping the switching frequency constant is presented. The LCL SRFB converter is simulated using PSPICE software and the results are verified experimentally on a prototype converter.

The various types of converter are described, and the history of resonant power supplies is briefly sketched. The differences between pulse-width-modulated (PWM) switch mode power supplies and resonant power supplies are discussed. Single-switch, multiple-switch, and series and parallel resonant converters are examined. The control of resonant converters is addressed. Hardware is briefly considered. >

In recent years, induction heating applications assisted by electronic power control have been very appealing. For melting applications, induction heating is widely used as it seems to be appropriate and provides higher efficiency, zero pollutants, non-contamination of material, etc. in comparison with conventional heating. The conventional variable frequency control scheme is not sufficient for melting applications because of its high switching loss, low efficiency, and lower heat rate. A superlative control technique is required to control the output power smoothly, for a high heating rate with minimum power loss, and to lower the number of components. In this paper, a capacitorless self-resonating bifilar coil is proposed for induction surface melting applications. The performance of the system in terms of modular losses, heat rate, and efficiency is analyzed for various power methods such as pulse duty cycle control, phase shift control, pulse density modulation control, and asymmetric duty cycle control. An experimental validation is performed for the 1 kW prototype, and the heating rate, efficiency, and modular losses are calculated. The control technique is digitally validated using a PIC16F877A microcontroller with 30 kHz switching frequency. The temperature distribution is analyzed using a FLIR thermal imager. Among the tested methods, pulse density modulation-based control provides smooth and varied power control from 0% to 100% with minimum modular losses. The efficiency of the system is 89% at a rated output power and is greater than 85% for pulse density modulation control with a fast heating rate.

In an Electric Vehicle a galvanically insulated auxiliary power module of suitable power size is employed to interface the high-voltage main energy storage battery to the low voltage auxiliary loads. Such converter must be reliable, efficient and compact. Resonant converters have reached widespread application as they are characterized by high efficiency and low Electromagnetic Interference (EMI). Resonant converters are usually operated in Pulse Frequency Modulation (PFM) with fixed duty cycle. In case of high power applications characterized by wide output voltage regulation, Pulse Width Modulation (PWM) can be beneficially adopted to extend the continuous modulation operation at low output voltage / low output power. This work analyses drawbacks and critical aspects of use of PWM along with some modulation strategies able to minimize hard switching commutations in this operating condition. After a first analytical comparison, different PWM strategies are evaluated by means of numerical simulations and experimentally assessed. A Quasi-Resonant control is proposed and assessed by means of simulation, resulting in an effective solution to hard switching commutation.

Modeling and Voltage Control of Bidirectional Resonant DC/DC Converter for Application in Marine Power Systems

Voltage equalization circuit for retired batteries for energy storage applications

This paper presents a comparative evaluation of Fuzzy Logic FLC Controller and Open loop Controller for a modified LCL Resonant Converter has been simulated and the performance is analyzed. A three element LCL Resonant converter working under load independent operation is presented in this paper. In this work, the applicability of the ARM Advanced RISC Machine processor LPC 2148 is to be investigated as the controller for resonant converter. The simulation study indicates the superiority of Fuzzy Logic control over the conventional control method. The evaluation version of MATLAB was used to model the LCL topology for varied loads and LCL configurations. A LCL Resonant Inverter is proposed for applications in high frequency distributed AC power systems and Resonant Converter is proposed for applications in many space and radar power supplies. The advantages of the LCL topology are low total harmonic distortion THD high efficiency and the ability to handle varying loads.

This study presents a comparative evaluation of proportional integral (PI) controller and fuzzy logic controller (FLC) for a modified Inductance-Capacitance-Inductance resonant converter. It has been simulated and the performance is analysed. A three-element LCL resonant converter working under load-independent operation is presented in this study. In this study, the applicability of the Philips Advanced RISC Machine (ARM) processor LPC 2148 is also investigated as the controller for resonant converter. The comparison study indicates the superiority of fuzzy control over the conventional control methods and these results are presented. MATLAB was used to model the LCL topology for varied loads and LCL configurations. The LCL resonant inverter is proposed for applications in high-frequency distributed AC power systems and resonant converter is proposed for applications in many space and radar power supplies. This study presents the design, simulation and experimental results for a 133-W, 50-KHz LCL resonant converter having efficiencies >89% down to resistive loads of 50%. Efficiencies >80% were obtained at significantly reduced loads (11%).

This paper develops a novel single-switch resonant power converter for renewable energy generation applications. This circuit topology integrates a novel single-switch resonant inverter with zero-voltage-switching (ZVS) with an energy-blocking diode with zero-current-switching (ZCS). The energy-blocking diode with a direct current (DC) output filter filters the output stage of the novel single-switch resonant inverter. Only one active power switch is used for power energy conversion to reduce the cost of active power switches and control circuits. The active power switch is controlled by pulse-width-modulation (PWM) at a fixed switching frequency and constant duty cycle. When the resonant converter is operated at discontinuous conduction mode (DCM), the inductor current through the resonant tank could achieve ZCS of the energy-blocking diode. Accordingly, a high energy conversion efficiency is ensured. Operating principles are derived and analyses are carried out based on the equivalent circuits for the proposed power converter under different operating modes. The operating principles of the converter were verified using a 32.4W, 70kHz experimental PV-powered load system. Given an appropriately chosen circuit parameters, the active power switch can be operated with zero-voltage switching and a measured energy conversion efficiency of the proposed topology of 97.3% can be achieved. Experimental results demonstrate a satisfactory performance of the proposed topology, which is especially suited to the energy conversion applications in renewable energy generation systems.

A novel CLL resonant converter with a semi-bridgeless active rectifier (S-BAR) is analyzed, and its hybrid control strategy is proposed in this paper. This topology is developed by replacing rectifier lower diodes with synchronous switches and regulation by a phase-shifted pulsewidth-modulation signal. Theoretical and simulation results show that the performance of the proposed S-BAR is appropriate for resonant converters and secondary-side controlled infrastructure requiring a wide voltage range control at the secondary side. The hybrid control algorithm is obtained with the phase-shift and frequency tuning considering the voltage at the load terminal. High efficiency can be maintained by this proposed control, reducing conduction losses and providing zero-voltage switching soft-switching condition with a wide output voltage range. To confirm the performance of the proposed converter, experimental results are provided for which the output voltage/current range from 0 to 80 V/0 to 8.75 A with an input of 120 V and an average efficiency value of 93%.

This paper proposes a simple structure highly efficient low-element-count non-isolated constant output current resonant converter for wide input voltage range and high-efficient applications. The converter is developed by combining a basic buck-boost converter with a half-bridge LCC resonant converter to improve the adjustable voltage conversion ratio. In the proposed structure, most of the output power is fed directly, which reduces the conduction power losses and increases efficiency by reduction of the processed power and the switches and rectifier diodes voltage stress is significantly decreased due to cascaded outputs structure. It operates at the resonant frequency to achieve a constant output current feature for applications such as LED drivers and battery chargers and the output current is regulated by the pulse-wide modulation (PWM). The proposed converter can achieve zero-voltage switching (ZVS) operation for all switches and zero-current switching (ZCS) operation for all diodes over a wide range of the input voltage and load conditions. The proposed structure is analyzed in detail. To verify the proposed converter performance, a 21 W laboratory prototype is realized and tested for the wide input voltage range of 12–40 V to provide 350 mA output current. The proposed converter achieves high peak efficiency of 98.15%.