Half-bridge Resonant Inverter Research Articles

An Input-Current Shaping and Soft-Switching Drive Circuit Applied to a Piezoelectric Ceramic Actuator.

Piezoelectric ceramic actuators utilize an inverse piezoelectric effect to generate high-frequency vibration energy and are widely used in ultrasonic energy conversion circuits. This paper presents a novel drive circuit with input-current shaping (ICS) and soft-switching features which consists of a front AC-DC full-wave bridge rectifier and a rear DC-AC circuit combining a stacked boost converter and a half-bridge resonant inverter for driving a piezoelectric ceramic actuator. To enable ICS functionality in the proposed drive circuit, the inductor of the stacked boost converter sub-circuit is designed to operate in boundary-conduction mode (BCM). In order to allow the two power switches in the proposed drive circuit to achieve zero-voltage switching (ZVS) characteristics, the resonant circuit of the half-bridge resonant inverter sub-circuit is designed as an inductive load. In this paper, a prototype drive circuit for providing piezoelectric ceramic actuators was successfully implemented. Experimental results tested at 110 V input utility voltage show that high power factor (PF > 0.97), low input current total harmonic distortion (THD < 16%), and ZVS characteristics of the power switch were achieved in the prototype drive circuit.

Design Methodology of Series Resonant Half Bridge Inverter for Induction Cooker

Design Methodology of Series Resonant Half Bridge Inverter for Induction Cooker

A Novel and Cost-Effective Drive Circuit for Supplying a Piezoelectric Ceramic Actuator with Power-Factor-Correction and Soft-Switching Features

This paper proposes a novel and cost-effective drive circuit for supplying a piezoelectric ceramic actuator, which combines a dual boost AC-DC converter with a coupled inductor and a half-bridge resonant DC-AC inverter into a single-stage architecture with power-factor-correction (PFC) and soft-switching characteristics. The coupled inductor of the dual boost AC-DC converter sub-circuit is designed to work in discontinuous conduction mode (DCM), so the PFC function can be realized in the proposed drive circuit. The resonant tank of the half-bridge resonant inverter sub-circuit is designed as an inductive load, so that the two power switches in the presented drive circuit can achieve zero-voltage switching (ZVS) characteristics. A 50 W-rated prototype drive circuit providing a piezoelectric ceramic actuator has been successfully implemented in this paper. From the experimental results at 110 V input utility-line voltage, the drive circuit has the characteristics of high power factor and low input current total-harmonic-distortion factor, and two power switches have ZVS characteristics. Therefore, satisfactory outcomes from measured results prove the function of the proposed drive circuit.

Power Losses and Current Distribution Studies by Infrared Thermal Imaging in Soft- and Hard-Switched IGBTs Under Resonant Load

A test bench is proposed to study, at die-level, the power losses and current distribution in power devices. It is based on an infrared camera and a flexible half-bridge resonant inverter with a tunable resonance frequency f res . With this setup, the die surface temperature is acquired in steady state, while the device is under real operation. The power losses are derived from the temperature mean value averaged, first, over a few switching cycles and, then, across the die surface. By contrast, the current distribution is inferred from the spectral component of the surface thermal map at the switching frequency (f Sw ). As a proof of concept, two case studies are reported considering 650 V-40 A insulated gate bipolar transistors (IGBTs) soft- and hard-switched within and outside the zero voltage switching condition. First, the power losses are analyzed under switching conditions representative of domestic induction heating applications (f res = 29.6 kHz) at f Sw = 40 kHz and f Sw = 20 kHz. Second, the power losses and local current distribution are investigated when f res = 9.25 kHz at f Sw ranged from 8.91 to 9.51 kHz. Such results are assessed with power losses electrical measurements and simulations, obtaining a satisfactory agreement. Moreover, hot spots are identified as current crowding points at f Sw , whose location is fixed by the bonding wires attachment to the die and the device edge termination. As main benefits of this technique, a higher spatial resolution is achieved and problems related with noisy electrical measurements resulting from the insertion of the used probes or transducers, power circuit stray elements, or device packaging parasitics are avoided.

Analysis of the Acoustic Noise Spectrum of Domestic Induction Heating Systems Controlled by Phase-Accumulator Modulators

In domestic induction heating applications, the modulation technique applied to the inverter has a high influence on the acoustic noise emissions. These noise emissions must be avoided, since they may be audible and annoying to the final user. This paper analyzes the acoustic noise emissions that appear when a series half-bridge resonant inverter is operated with a phase-accumulator-based modulator. This modulation technique has the advantage of operating in the frequency domain, and it is compared with the classical pulsewidth modulator regarding the audible noise generated. The frequencies of the tones in the acoustic noise spectrum are theoretically calculated from the parameters of the phase-accumulator-based modulator. The spectral flatness measure is used to quantify the number of cases in which tones are generated by the modulation. Two techniques are applied to the phase-accumulator-based modulator, and their effect is tested. Theoretical results are experimentally verified.

Merits of SiC MOSFETs for high-frequency soft-switched converters, measurement verifications by both electrical and calorimetric methods

ABSTRACTThis paper quantifies the soft switching loss of a 1.2 kV SiC MOSFET module via a calorimetric method in a 78 kW full-bridge resonant inverter switched at approximately 200 kHz. By switching the SiC MOSFET just before the zero crossing of the current during turn-off and at perfect zero voltage during turn-on, this converter yielded an efficiency of roughly 99 %. Then, a simplified laboratory setup, including only a half-bridge series resonant inverter topology with split DC-link capacitors and an LC load, was built such that a real inverter operation was emulated, and thereby, turn-off loss was measured via an electrical method. A discrepancy of approximately 10 % is found between the two loss measurement methods, and the possible source for this difference is discussed. Furthermore, a standard double pulse test was also performed in an inductive clamped buck converter for measuring the hard switching loss. Finally, a comparison of losses obtained from the hard versus resonant topologies at the same load current was accomplished, which verifies the substantial benefits of the latter over the former. Thus, the merits of SiC MOSFETs for high frequency soft switched converters are demonstrated, which is the main contribution of this paper.

FPGA-Based Automatic Frequency-Controlled Resonant Inverter for Induction Heating System

This paper presents a frequency tracking control for the half-bridge high-frequency series resonant inverter-fed induction heating system. The aim of this research work is to obtain dynamic zero current switching in the switches of the inverter even under variation in the load. Closed loop frequency tracking control system is developed to track the resonant frequency during step change in load. The change in load is identified by sensing the phase angle between voltage and current. The error in the phase angle is used to track the frequency. Simulation of an open loop and closed loop IH systems has been performed. A simulation study is performed to verify the effect of controller. Simulation results of half-bridge series resonant inverter system with the proposed controller are presented to prove the performance of the developed control system. The results are validated with the prototype of system controlled by FPGA controller.

A Phase Angle Self-Synchronization Topology for Parallel Operations of Multi-Inverters in High Frequency AC Distribution

—High frequency ac (HFAC) power distribution system (PDS) has been known as the effective alternative of dc power distribution system (DC PDS) because of its excellent advantages such as high power density, high efficiency, fast dynamic response and fewer conversion stages. Multiple HFAC inverters are operated in parallel to satisfy the source side requirements like high power grade, safety margin and reliability. In order to eliminate circulation current caused by the amplitude and phase differences among the inverters, the amplitude and phase of individual inverter are required to be synchronous. However, parallel controls become extremely complicated as amplitude and phase are coupled together in full-bridge inverter with traditional phase-shift modulation. In this paper, a controllable half-bridge LCLC resonant inverter and dual-PWM modulation are presented with phase angle self-synchronization. Control strategy is given for voltage adjusting and phase-amplitude decoupling. Besides, the resonant network normalization parameters and control angle is summarized to ensure soft-switching. The simulation model and experimental prototype are implemented with the output frequency of 25 kHz. The experiment results and theoretical analysis agree well to verify the features of the proposed inverter.

A closed-loop power controller model of series-resonant-inverter-fitted induction heating system

Abstract This paper presents a mathematical model of a power controller for a high-frequency induction heating system based on a modified half-bridge series resonant inverter. The output real power is precise over the heating coil, and this real power is processed as a feedback signal that contends a closed-loop topology with a proportional-integral-derivative controller. This technique enables both control of the closed-loop power and determination of the stability of the high-frequency inverter. Unlike the topologies of existing power controllers, the proposed topology enables direct control of the real power of the high-frequency inverter.

Analysis and Design of Modified Half-Bridge Series-Resonant Inverter With DC-Link Neutral-Point-Clamped Cell

In this paper, a modified half-bridge (HB) resonant inverter topology with a dc-link neutral-point-clamped cell is proposed. A pseudo asymmetrical voltage-cancellation PWM method and a control strategy are introduced. The proposed topology can maximize the inverter output power factor, and minimize variations in the switching frequency. In addition, most switches are clamped to half of the dc input voltage at turn-off, increasing the overall efficiency of the system for a wide load range. The efficiency of the proposed inverter is improved up to 7% at light-load conditions compared with that of the conventional HB inverter. Informative expressions for performance comparison between the proposed inverter and its counterpart are provided. In addition, the losses in the inverter primary components are analytically analyzed in detail. For validation, a 120-W prototype is implemented, and experimental results are presented.

Phase‐shift modulation in double half‐bridge inverter with common resonant capacitor for induction heating appliances

In this study, the application of the phase-shift modulation to a double half-bridge resonant inverter supplying inductive loads with a common resonant capacitor is analysed in order to control the output power provided to the load of each converter. This study is focused on the application of such modulation to a cost-effective solution for domestic induction heating appliances with at least two burners heating up simultaneously two pots. The burners, also called inductor-pot systems, are usually electrically modelled by their equivalent impedances, Z coil ( ω ). The proposed modulation is suitable to control the power provided to inductor-pot systems with different equivalent impedances. The control variables of each half-bridge inverter, that is, switching frequency, f sw o , and duty cycle, D , have been assumed identical to both inverters in order to simplify the analysis, but, a new control parameter, the phase-shift between inverters, φ , is employed. In the analysis, it has been proved that the power dependence with respect to the phase-shift between the inverter is almost totally due to the first harmonic contribution of the current. Finally, the main results of the analysis are checked by means of experimental measurements.

A Comparative Performance Investigation of Single-Stage Dimmable Electronic Ballasts for Electrodeless Fluorescent Lamp Applications

This paper presents a comparative investigation, design and development issues about six different single-stage topologies, applied as electronic ballasts, for electrodeless fluorescent lamps. The ballast is intended to feed a 100 W lamp at 250 kHz, with dimming feature. The proposed topologies use different converters for the power factor correction (PFC) stage: Buck-Boost, SEPIC, Zeta, Cúk, Flyback, and Boost. All of them operate in discontinuous conduction mode. A resonant half-bridge inverter is used as lamp power control (PC) stage. The integration of both stages (PFC and PC) is proposed in this paper. In this way, it is possible to reduce the number of active switches, as well as simplify the required driving and control circuitry. Experimental results demonstrate the feasibility of the proposed dimming technique that achieved around 56% lamp power dimming, from 100 W down to 44 W. The implemented topologies attained high average power factor (>0.98), and low line current average total harmonic distortion (<;15.3%). A comparison among all the proposed topologies in terms of power factor, harmonic distortion, efficiency and number of components is presented. Finally, a comparison between an integrated and a nonintegrated SEPIC half-bridge converter is also performed.

Selection of Power Semiconductor Switches in Modified Half Bridge Resonant Inverter Fitted Induction Heater in Power Line for Less Harmonic Injection

&lt;p&gt;This paper presents an approach to minimize the harmonics contained in the input current of single phase Modified Half Bridge Resonant inverter fitted induction heating equipment. A switch like IGBT, GTO, and MOSFET are used for this purpose. It analyzes the harmonics or noise content in the sinusoidal input current of this inverter. Fourier Transform has been used to distinguish between the fundamental and the harmonics, as it is a better investigative tool for an unknown signal in the frequency domain. An exhaustive method for the selection of different power semiconductor switches for Modified Half Bridge Resonant inverter fed induction heater is presented. Heating coil of the induction heater is made of litz wire which reduces the skin effect and proximity effect at high operating frequency. With the calculated optimum values of input current of the system at a particular operating frequency, Modified Half Bridge Resonant inverter topology has been simulated using P-SIM software. To obtain the Input current waveforms through it, further analysis has been employed. From this analysis selection of suitable power semiconductor switches like IGBT, GTO and MOSFET are made. Waveforms have been shown to justify the feasibility for real implementation of single phase Modified Half Bridge Resonant inverter fed induction heater in industrial application.&lt;/p&gt;

A New Asymmetric Duty-Cycle Control for a ZVS Self-Oscillating Half-Bridge Inverter

In this paper, a simple power control scheme for a constant frequency self-oscillating inverter with a variable duty cycle is proposed. The proposed topology, based on the half-bridge series resonant inverter, can achieve a stable and efficient Zero-Voltage-Switching (ZVS). As a consequence, the converter efficiency is significantly improved. This novel technique consists in injecting a DC control current through a saturable core providing a variable asymmetric control as a function of the injected current; we can therefore control and regulate the output power while maintaining the switching frequency close to the resonant one. The control principles of the proposed method are described in detail and its validity is verified through simulated and experimental results on 750 W with constant frequency variable power.

Design of adaptive dead-time control circuit for resonant half-bridge driver

To decrease the switching loss and the dead-time effect of resonant half-bridge inverter, a novel adaptive dead-time control circuit of resonant half-bridge driver Integrated Circuit (IC) is presented. Without increasing the pin number of IC, this circuit takes a novel strategy to adaptively regulate dead time to a temperate range between high and low thresholds. The high and low thresholds are adaptive to the fall time of output signal in a half-bridge clock cycle. The IC of the designed circuit is suitable for high-voltage applications. The dead-time regulation range of this circuit achieves 0–3.5 µs. The range of temperate dead-time state is 300 ns. The failure signal of this circuit can protect the IC and peripheral power devices by regulating operation in three clock cycles. Both simulation and measurement of the proposed circuit in a half-bridge driver IC with an operating frequency at 50 kHz are presented based on the 0.5 µm 700 V BCD process. The results of simulation and measurement show that the presented circuits’ performance is perfect.

Serial Resonant Converter and Load Coil for High Frequency Heating

The paper deals with the design of the voltage source half-bridge resonant inverter with the specific load coil, which is suitable for induction heating applications. To ensure the correct functionality and right frequency range of the self-resonant converter, the parameters as inductance, self-capacitance and resistance of the coil have to be obtained. Parameters of the coil are estimated by utilizing software that uses finite elements method of solution. In order to estimate the accuracy of model, the experimental verifications were taken. For this purpose, the spiral coil made on printed circuit board was created and its parameters were calculated, simulated and compared with measurement results.

Analysis and Design of a Single-Stage High-Power-Factor Dimmable Electronic Ballast for Electrodeless Fluorescent Lamp

A methodological study of an electronic ballast for electrodeless fluorescent lamps (EFLs) including design and development issues is presented in this paper. The ballast is intended to feed a 100-W EFL at 250 kHz with dimming feature. The proposed topology is composed of a single-ended primary-inductance converter, used as power-factor (PF)-correction stage, integrated with a resonant half-bridge inverter, used as lamp-power control stage. The integration of both stages is proposed in this paper, in order to reduce the number of active switches, as well as to simplify the required driving and control circuitry for this application. Experimental results demonstrate the feasibility of the proposed solution that achieves 54% lamp-power dimming (46 W). The implemented topology attained very high PF (0.989) and low line-current total harmonic distortion (14.929%), without using electromagnetic interference filter, while the measured efficiency was 87% at nominal lamp power.

Computational Modeling of Two Partly Coupled Coils Supplied by a Double Half-Bridge Resonant Inverter for Induction Heating Appliances

In this paper, an induction heating system composed of two partly coupled coils connected to a double half-bridge resonant inverter is deeply analyzed. Induction coils are electrically characterized by their electrical equivalents, usually a series RL circuit, where the inductance is determined by the magnetic energy stored in the system and the resistance is associated with the power dissipated in the load, generally, a metallic workpiece. The aim of this work is to obtain the electrical equivalent of an inductor system with two concentric coils used in domestic cookers by means of computational methods, in order to be included into the models used in computational aided electronic tools to simulate the time-domain behavior of the associated electronics. The multiple-coil system is characterized with a frequency-dependent impedance matrix, where the diagonal terms are the impedance of each isolated coil, and the nondiagonal terms are coupling impedance components describing the mutual coupling between coils. The impedance matrix is calculated with finite-element analysis tools, and equivalent passive networks are proposed to perform time-domain simulation with a good accuracy in the frequency range of interest. The proposed system has been experimentally verified, obtaining accurate time-domain waveforms and output power calculation.

Electric Equivalent Model for Induction Electrodeless Fluorescent Lamps

This paper presents an electric equivalent model applied to induction electrodeless fluorescent lamps. The model is based on passive components and takes into account the real and reactive lamp power. The presented model and its obtention methodology will be an important tool for ballast designers. One of the most important features of the proposed methodology is the concern regarding core losses and lamp reactive characteristics, because nowadays there are no electric models including these characteristics. In order to obtain and validate the electrodeless lamp model, a series-parallel resonant half-bridge inverter is used as ballast. Plasma and lamp windings are modeled as resistances and reactances depending on the lamp power. Simulations employing the proposed model are also presented, showing an excellent agreement with experimental results.

평판 유도발열체의 거리·주파수 가변특성에 관한 연구

Induction-heated system is innovative system which applied IH(Induction Heating) magnetic induction heating generated from induction-heated metallic package and high-frequency power circuit technique for thermal converse technique. In this occurs not burning, so that the working environment and deterioration of products can be improved. This technique is used high frequency inverter. By using high frequency inverter high frequency in the range of ㎑ can be made with conventional alternative current. In this contribution IGBT module is used for high frequency inverter.<BR> In this paper are discussed analysis of characteristics according to the each frequency and produced Flat plate induction heating system using 1.5㎾-class half-bridge resonant inverter. In addition, operating characteristics of the system to changes in the distance between the coil and the heater, applications of system are also discussed.