Resonant Inverter Topology Research Articles

Short-voltage pulse generation for induction heating load detection on a multi-output inverter with shared power devices

Purpose The purpose of this paper is to develop a load detection method for domestic induction cooktops. The solution aims to minimize its impact in the converter power transmission while enabling the estimation of the equivalent electrical parameters of the load. This method is suitable for a multi-output resonant inverter topology with shared power devices. Design/methodology/approach The considered multi-output converter presents power devices that are shared between several loads. Thus, applying load detection methods in the literature requires a halt in the power transfer to ensuring safe operation. The proposed method uses a complementary short-voltage pulse to excite the induction heating (IH) coil without stopping the power transfer to the remaining IH loads. With the current through the coil and the analytical equations, the equivalent inductance and resistance of the load is estimated. The precision of the method has been evaluated by simulation, and experimental results are provided. Findings The measurement of the current through the induction coil as a response to a short-time single-pulse voltage variation provides enough information to estimate the load equivalent parameters, allowing to differentiate between no-load, non-suitable IH load and suitable IH load situations. Originality/value The proposed method provides a solution for load detection without requiring additional circuitry. It aims for low power transmission to the load and ensures zero-voltage switching and reduced peak current even in no-load cases. Moreover, the proposed solution is extensible to less complex converters, as the half bridge.

A simple and efficient resonant DC link inverter with low current stress on main switch

This paper proposes a simple and efficient resonant DC link inverter topology with low current stress on main switches. The inverter has a straightforward structure and is readily controllable, avoids the auxiliary resonant current passing through the main switches of the inverter, and the current passing through the main switches remains consistently equivalent to the load current, thus reducing the current stress and the switching loss of the main switches, thereby the inverter’s efficiency is increased. The proposed inverter’s operating principle is examined and contrasted with the inverter described in the literature. Ultimately, the validity of the resonant DC link inverter is demonstrated through simulation.

A Method to Reduce Torque Ripple of Brushless DC Motor

In order to improve the accuracy of the commutation of the brushless DC motor rotor, considering that the traditional modulation method will be affected by the conduction voltage drop of the switch tube and the freewheeling diode, resulting in the non-conduction phase freewheeling during the non-commutation period Torque ripple, which is also the main cause of torque ripple. Therefore, it is a positionless control method that controls the non-conducting phase torque ripple PWM_ON_PWM modulation. However, due to PWM modulation, off-phase freewheeling will inevitably occur. For this, the resonant DC link soft-switching inverter topology is used to suppress the off-phase freewheeling. Through experiments and simulations, it is proved that these combined methods can effectively reduce the size of torque ripple.

Mains-Synchronized Pulse Density Modulation Strategy Applied to a ZVS Resonant Matrix Inverter

Multi-output inverters have become a key enabling technology to increase surface flexibility in domestic induction heating appliances. The most commonly used power converter topologies are based on electromechanical relays in order to multiplex the connected loads and obtain a proper heat distribution. This solution, which is used in combination with other modulations such as square waveform, relies on the thermal inertia of the pot as it needs long power-averaging periods to reduce the reiteration of the switching noise. However, it presents a significant limitation in terms of acoustic noise, reliability, and thermal performance. To overcome these limitations, complete solid-state inverters that can be operated at higher frequencies are proposed. This change in the design paradigm of the pulse density modulation strategies leads to improved thermal control in the pot and better user experience, but at the same time increases challenges due to design constraints imposed by electromagnetic compatibility regulations. This article analyzes the possibilities of a new mains-synchronized pulse density modulation applied to a flexible induction cooktop that uses a multiple-output ZVS resonant inverter topology. The feasibility of the control strategies has been tested by means of a prototype featuring 12 2-kW induction heating loads.

Proposal of a Three-Degree-of-Freedom Linear-Rotational Resonant Actuator and Inverter Topology

The aim of this study is to propose a new three-degree-of-freedom linear-rotational resonant actuator and its controller. To realize all of the resonant motion, four-phase coils and three sets of the permanent magnet are arranged symmetrically. In addition, in order to control the proposed actuator, inverter topology with six-switches is presented. Parameter characteristics obtained through finite-element analysis support the validity of the proposed actuator. Finally, dynamic simulation is performed to verify the effectiveness of the proposed actuator.

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.

Design and Analysis of the Performance of a Solar Driven Micro-Inverter Using Single Ended Primary Inductance Converter Topology

In typical solar power installations, multiple modules are connected to the grid through a single high-power inverter. However, an alternative approach is to connect each solar module directly to the grid through a micro-inverter. This approach makes the system robust to single module failures and results in better power tracking. PV based cower conditioning system need a high-efficiency dc–dc converter capable of regulation over a wide input voltage range for Maximum Power Point Tracking (MPPT) and a high-efficiency micro-inverter. To diminish the ground leakage currents, also to use a high-efficiency system, the proposed concept is required for this micro-inverter to provide galvanic isolation between the PV module and the inverter. This concept involves the design of a micro-inverter topology which includes design of Single Ended Primary Inductance Converter (SEPIC) dc/dc converter, isolated resonant inverter and a cyclo-converter. The SEPIC converter topology yields high efficiency through constant voltage MPPT algorithm. The Resonant inverter topology produces efficient output through low circulating currents, Zero Voltage Switching (ZVS), low-current switching of the primary side devices, and Zero Current Switching (ZCS) of the output diodes. This Resonant inverter topology is also able to provide voltage regulation through basic fixed-frequency Pulse Width Modulated (PWM) control. The features of proposed system can able to achieve w the simple addition of a secondary-side bidirectional ac switch to the isolated series resonant converter.

Autonomous Wideband Piezoelectric Energy Harvesting Utilizing a Resonant Inverter

Piezoelectric energy harvesters generate electrical power from ambient mechanical vibrations, making these vibrations a viable energy source for powering wireless sensor and identifier nodes. In order to harvest an appreciable amount of power, piezoelectric devices are typically inserted into high-Q mechanical resonant structures that significantly limit their harvesting bandwidth. The dynamic active energy harvesting method has been proposed as a way to widen the bandwidth of resonant piezoelectric energy harvesters; however, an autonomous design has not yet been demonstrated. This paper demonstrates the first autonomous implementation of this method. This was accomplished through the use of a resonant inverter topology in combination with a low-power analog control circuit design that reduces the computational demand of the microcontroller. Experimental results using the Mide Volture V20w piezoelectric device show that the harvested power is up to twice that of the adaptive rectifier method. These results include previously ignored loss mechanisms such as control losses, gating losses, and phase detection losses, making this system the first autonomous energy harvesting system of its kind.

Wattage-independent dynamic conductance model of compact fluorescent lamps: Validation and application in high-frequency operation

A wattage-independent (7–18 W) compact fluorescent lamp (CFL) model has been developed in Matlab-Simulink and validated in low-frequency (50 Hz) operation in our earlier work. In this paper, the same lamp model is simulated for high-frequency operation and then validated experimentally with a 9 W test CFL driven by a compatible electronic ballast (e-ballast). Simulation results have shown a maximum 6.4% deviation compared to the measured data. Thereafter, the developed model is applied to obtain the arc resistance versus power and power versus frequency characteristics of CFLs required to design dimmable e-ballasts. An algorithm is developed to compute design parameters of a dimmable e-ballast based on voltage-fed series-parallel resonant inverter topology. The electrical performance of the designed e-ballast is simulated at three different power levels (100%, 75% and 50%) using Matlab-Simulink.

Resonant voltage limiting technique of single‐ended resonant inverter for induction heating

Single-ended resonant inverter topology is widely used in domestic induction heating (IH) application due to its concise structure and cost effectiveness. Whereas high resonant voltage caused by the energy transfer between load inductor and resonant capacitor in the IH system may negatively affect the operation of system and long-term reliability. Generally, 1200 V rating IGBT is popularly used for single-ended IH cookers. However, abnormal conditions of AC supply suddenly increases the resonant voltage thereby IGBT can be destructed. Resonant voltage limiting technology is proposed by restricting the maximum current flow to the load inductor in order to relieve the voltage stress across the IGBT. The effectiveness of the proposed method is verified for AC supply distortion by using 1.35 kW single-ended IH system.

Three‐phase double auxiliary resonant commutated pole inverter topology and analysis of its working principle

This study presents a double auxiliary resonant commutated pole (ARCP) inverter topology and modulation strategy. In the proposed inverter, the zero-voltage-switching (ZVS) turn-off of auxiliary switches influenced by parasitic circuit elements from the wiring process can be avoided. It is assured that the auxiliary switches achieve ZVS turn-off reliably. Hence, the reliability of the ARCP inverter is improved, especially in high-power application. According to the equivalent circuits in different operation modes under the proposed modulation strategy, the working principle, soft-switching implementation condition, and parameter design procedure of the proposed inverter are analysed successively in this study. Finally, a 10 kW, 16 kHz double ARCP inverter prototype is built. Experimental results are given to demonstrate the validity of the proposed 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.

A Comparative Study of Power Supply Architectures in Wireless EV Charging Systems

This paper examines two of the primary power supply architectures being predominantly used for wireless electric vehicle (EV) charging, namely the series LC (SLC) resonant and the hybrid series-parallel (LCL) resonant full-bridge inverter topologies. The study of both of these topologies is presented in the context of designing a 3-kW primary-side controlled stationary wireless EV charger with nominal operating parameters of 30-kHz center frequency, a range of coupling in the neighborhood of 0.18-0.26, and a parallel secondary pick-up with partial series coil compensation. A comparison of both architectures is made in terms of their design methodology, physical size, cost, complexity, and efficiency. It is found that the SLC architecture is 2.45% less costly than the LCL topology. On the other hand, it is observed that the LCL architecture achieves almost 10% higher peak efficiency at rated load and minimum coupling. The study also showed that the SLC topology suffers from poor light load efficiency, while the LCL topology maintains very high efficiency over its full range of coupling and loading. The study also revealed that the capacitor voltage stress is significantly higher in the SLC topology. Finally, it is also shown that the control complexity of the SLC architecture is higher than that of the LCL architecture because of its sensitivity to changes in the reflected secondary impedance, which result in loss of constant current source and ZVS operation unless a suitable combination of parameters are modulated by the closed-loop controller.

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

<p>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.</p>

Flying Capacitor Resonant Pole Inverter Topology with Reduced Switch Voltage Stress

Increasing the bus voltage in high power applications has reached a limit for non-multilevel converters. This is caused, amongst others, by susceptibility to single event burnout induced by cosmic radiation. Single event burnout has a strong correlation to the voltage stress over the switching device. This paper proposes a soft switching multilevel converter to raise the power limit and reduce the susceptibility to cosmic radiation by adding a flying capacitor to a resonant pole inverter. A laboratory test circuit is built, and the circuit operation shows satisfactory agreement with the theoretical analysis and simulation results. The experimental results show that this converter module reliably reduces the voltage stress over the devices without interfering with the zero voltage switching capabilities. This is done with relatively low added complexity.

PWM Control for Actively Clamped Resonant DC-Link Inverter on Soft-Switching

Due to the active inverter in industrial application, if use hard switching mode, not only may have the switch losses, but also may produce electromagnetic interference and harmonic, these power quality is affected. This paper presents the design of a soft-switching active inverter, that active clamped resonant DC-link inverter topology was used on the main circuit, the voltage space vector pulse width modulation (SVPWM) control mode was used on control circuit, using TMS320LF2407DSP programming, while the AT89C51 was responsible for liquid crystal display task, data exchanged and coordinated between double CPU. The experimental results show that, the device switching-losses can effectively reduce, the switching frequency can improve, input power quality can improve.

Self-Oscillated Induction Heater for Absorption Cooler

Self oscillated resonant inverters have the advantages of low cost and simplicity. DC-AC power conversion can be achieved without using special drivers. In this study, self oscillated half bridge series resonant inverter topology is designed and applied to induction heater as a boiler part of home type absorption cooler system. The designed system has rapid and stable heating/cooling response compared to conventional resistance heated system. Self oscillated resonant inverter can achieve soft switching and maintain resonant tracking with simple and cheap drive circuit during all heating period. DOI: http://dx.doi.org/10.5755/j01.eee.19.10.5894

Design and Comparison of Capacitor Chargers for Solid-State Pulsed Power Modulator

This paper describes the design, implementation, and comparison of high-voltage capacitor chargers for a solid-state pulsed power modulator (SSPPM). The three different converter topologies are a series resonant converter operating at a discontinuous conduction mode with switching frequency control (SRC_DCM_SFC), a series resonant converter operating at a continuous conduction mode with phase shifted pulse width modulation control (SRC_CCM_PSPWMC), and a series-parallel resonant converter operating at the CCM with SFC (SPRC_CCM_SFC). On the basis of these converter topologies, 10-kWaverage high-voltage capacitor chargers are designed for the three types of SSPPMs, which have the following maximum output specifications: 1) SRC_DCM_SFC: 60 kV, 300 A, 3 kpps, and 50 μs; 2) SRC_CCM_PSPWMC: 10 kV, 50 A, 50 kpps, and 10 μs; and 3) SPRC_CCM_SFC: 40 kV, 150 A, 7 kpps, and 10 μs. Although the pulse output specifications are different, it is worth comparing the resonant inverter topologies and the control methods from the viewpoint of the losses, control characteristics, and merits and demerits of the high-voltage capacitor chargers. From the analysis and investigation of the three resonant inverters, the design procedure, including the determination of the resonant tank parameters, is provided, which considers the design of the high-voltage capacitor charger. PSPICE simulation is used to elucidate the effects of the resonant tank structure and its parameters, and the resonant current waveform and losses of the Insulated Gate Bipolar Transistor are compared. Finally, experiments for each charger are performed under various load conditions, and the comparison results of the three capacitor chargers, including the conduction and switching losses, control characteristics, and overall efficiency, are discussed in this paper.

Universal Ultrasonic Generator for Welding

The paper presents design and parameters of a multifunction ultrasonic generator manufactured by Tele and Radio Research Institute. E cient usage of ultrasonic welding and cutting technology depends on the ability to precisely control process parameters and tune those parameters to suit particular needs. Ultrasonic generator is responsible for such control and tuning. Presented design incorporates powerful 32 bit Cortex M4 microcontroller with oating point unit which allows using modern signal processing methods to calculate parameters of ultrasonic stack in real time. Calculated parameters, especially impedance of the stack are used to estimate load level and identify phases of the welding process such as melting of the welded material. Precise control of the output signal is possible due to innovative design of the direct digital signal synthesis unit implemented in programmable logic device (CPLD). Resonant inverter topology of the generator front end ensures high electrical e ciency of the device. Designed generator is equipped with various communication interfaces such as USB host and slave, Ethernet, Bluetooth, CAN and RS485. Multiple digital inputs and outputs together with load cell interface, 4 20 mA receiver and 0 10 V analog input enable the generator to monitor and control entire ultrasonic welding system without the need of a PLC unit.

Series resonant inverter with selective harmonic operation applied to all-metal domestic induction heating

Usually domestic induction appliances heat ferromagnetic pans. This technology is well known and it is successfully applied by many manufacturers. However, there are a number of non-ferromagnetic pans (made of aluminium, copper, copper-nickel or stainless steel) that cannot be properly heated by this technology. This study presents a modified half-bridge series resonant inverter topology that can be used to heat ferromagnetic and non-ferromagnetic pans by means of a selective harmonic operation technique. The proposed inverter topology has two topological configurations with two operation modes: the first-harmonic operation mode and the third-harmonic operation mode. These two operation modes and the design of the principal parts of the inverter are presented in this study. Experimental results obtained with a prototype are also presented. The performance of the proposed resonant inverter topology with ferromagnetic pans is satisfactory and with non-ferromagnetic pans is acceptable.