Resonant Inductor Research Articles

Adaptive Soft-Switching Control of Active-Clamping Three-Phase Inverters

Energy stored in the resonant inductor is critical to the zero-voltage switching (ZVS) of power semiconductor devices in soft-switching active-clamping three-phase inverters. Traditionally, the soft-switching PWM timing parameters are designed based on calibrated data table. However, for motor drives or general-purpose AC power supplies, their fundamental output amplitude and frequency may vary, which makes control of the soft-switching inverter complex. It would be time-consuming and tiring to manually calibrate soft-switching timing control parameters under various operation conditions. In this paper, an adaptive soft-switching control of active-clamping three-phase inverters is proposed. The resonant inductor energy storage is adjusted to the optimal value automatically. Principles and implementation of the control are introduced. Parameters design of the adaptive control is discussed. Finally, the proposed method is verified by experiments.

Design of 98.8% Efficient 400-to-48-V $LLC$ Converter With Optimized Matrix Transformer and Matrix Inductor

Data centers have seen a rapid increase in power consumption in recent years, and the 48 V power architecture has gained popularity due to its efficiency. However, the cost of efficient power supplies remains challenging due to their complicated magnetic designs. The search for efficient and cost-effective power supplies continues. This paper focuses on the implementation of the DC-DC stage of the power supply unit for the 48 V data center bus architecture. In this paper, we present a design process for a high-efficiency, high-power-density 3 kW 400 V to 48 V LLC converter for use in data centers. Through optimization of the matrix transformer's geometry, turn number, and resonant frequency, we achieve superior efficiency and power density compared to state-of-the-art designs. To address challenges with the printed circuit board PCB-based inductors, we propose the use of a resonant matrix inductor, which reduces the number of stacked PCB layers, simplifies the winding implementation, and lowers the AC loss. By integrating the matrix inductor with the matrix transformer, we create a modular and scalable magnetic structure suitable for a wide range of voltages and currents. We also introduce EMI shielding for the matrix transformer with a full-bridge rectifier, resulting in an 18 dB reduction in common-mode noise. The prototype achieved a peak efficiency of 98.8% and a power density of 600 W/in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> , demonstrating the effectiveness of the proposed design.

Performance Comparison of Electric Drives for Chopping/Shredding Sugarcane in Sugar Industry

A performance comparison of the conventional slip ring induction motor (SRIM) drive and the recently inducted variable frequency drive (VFD) in the sugar industry, for sugarcane preparation (chopping/ shredding of sugarcane), is carried out to assess their effectiveness and to explore better electric drives for the application. These high inertial machines demand high starting torque and mitigating means to reduce surge load due to the impact load imposed on them. Though, both the drives meet the requirement but the SRIM drives are subjected to huge slip power loss, low power factor, unequal load sharing problem for coupled motors and high drop in rpm, whereas VFDs are subjected to the problems of input current harmonics, high dV/dt stress and common-mode voltage (CMV). In this paper, along with the performance comparison a three/four-level multilevel inverter (MLI) fed open-end winding induction motor (OEWIM) drive is also proposed as an improvement over the existing ones.

Design and Optimization of an Integrated Resonant Inductor With High-Frequency Transformer for Wide Gain Range DC–DC Resonant Converters in Electric Vehicle Charging Applications

Large-scale adoption of wide band gap semiconductors in switched mode power converters enables miniaturization of power electronic systems. With switching frequencies approaching a few hundred kilohertz - megahertz range, efficient and compact design of magnetic components are crucial for future generation power supplies in data centers or electric vehicle (EV) applications. In a typical two-stage AC-DC power supply, the DC-DC stage is often constructed using a resonant converter with galvanic isolation provided by a high-frequency transformer. In such systems, the integration of an inductor in the resonant network with the transformer helps improve power density and reduces component count and cost. However, the integration of magnetic components can result in increased losses, deteriorating the performance of the power conversion system. In this paper, a magnetic structure along with an optimization methodology is presented to integrate a predefined resonant inductor as leakage inductance of the high-frequency transformer achieving minimum penalty on converter efficiency using planar core geometry and printed circuit board (PCB) based windings. The proposed methodology is applied to integrate a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$7.8 \mu \rm{H}$</tex-math></inline-formula> inductor with a 2:1 transformer for a 6.6 kW, 500 kHz LCL-T resonant DC-DC stage utilizing GaN transistors in an onboard battery charging converter. On the prototype converter using the optimized integrated magnetic component, a peak efficiency of 98.4% was obtained using PCB windings. Furthermore, the integrated magnetic component achieved 64 kW/L power density in the demonstrator prototype.

High-Frequency 12 V Regulated LLC Bus Converter With Integrated Multiphase Inverse Coupled Resonant Inductor

In the application of 48 V bus converter, the traditional multiphase regulated <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter has some shortcomings, such as insufficient gain range, low light-load efficiency, and difficult current sharing. In order to improve the performance, this article investigates a comprehensive design scheme of multiphase interleaved magnetic integrated <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter, which can extend the gain range and achieve active current sharing simultaneously. First, a new structure of multiphase inverse coupled resonant inductor and magnetic integrated transformer is proposed. Then, a high-precision magnetic circuit model is constructed to optimize the design of integrated inductor and transformer. On this basis, the three-phase interleaved magnetic-integrated <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter prototype is manufactured, which has a 36–75 V input voltage range and a 12 V regulated output voltage. In addition, the prototype can output 1080 W power in a quarter brick and has a power density of 716 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The maximum efficiency at rated input voltage is 97.5% and remains above 96% over the main input voltage range. As shown by the quantitative performance comparison results, the proposed converter is superior to other state-of-the-art solutions in terms of the comprehensive performance.

Study of half‐bridge series‐resonant induction cooker powered by line rectified DC with less filtering

AbstractThis paper presents an analysis and design strategy for a half‐bridge series resonant induction heating (HB SR‐IH) cooker powered by a rectified sinusoidal DC. The simplified equivalent circuit of an induction cooker is modelled by a train of rectified sinusoidal DC pulses chopped at the switching frequency. An average root‐mean‐square (RMS) method is proposed to calculate the RMS resonant voltage and current extrapolated to the power line frequency period. The stability of the cooker is achieved by properly setting the damping ratio in the root‐locus plane to keep the system running quasi‐resonantly at the required power. The power control of the SR HB‐IH cooktop is performed by forced commutation above the resonance frequency. A prototype of a 3 kW HB SR‐IH cooker was designed and implemented to validate the estimated results. Various waveforms from low power to high power are discussed and verified by damping ratio control. The SR HB‐IH cooktop achieves a high‐power factor of 0.95 to 0.995 when generating 300W to 3kW due to less filtered DC power. The power quality assessment showed that the total harmonic distortion (THD) of the line current and voltage measured at 3 kW was 4.1% and 3.5%, respectively.

Robot Fault Detection Based on Big Data

In order to improve the reliability of robot electrical fault detection and diagnosis, the author proposes a robot electrical fault detection and diagnosis method based on deep learning. Taking the return power and active power as constraints, the electrical fault data collection of the robot is carried out. Taking the resonant inductance and resonant capacitance of the robot electrical equipment as identification parameters, we conduct electrical fault differential feature mining. The fault features are extracted according to the time-delay distribution sequence of the electrical fault data of the robot, and the electrical fault detection and diagnosis results are output by using the deep learning function. Simulation results show that the author's method has a high accuracy probability for robot electrical fault diagnosis. The author's method is on average 14.7% higher than the neural network-based method and 24.5% higher than the expert system-based method. The accuracy rate of the author's method for robot electrical fault diagnosis is high. The author’s method is 16.6% higher than the neural network-based method on average and 34.2% higher than the expert system-based method. It is proved that the robot electrical fault detection and diagnosis based on deep learning has high accuracy and short time.

A Family of Bidirectional Series Resonant Converter With Sine-Wave Modulation in Wide Voltage Range

A topology family of bidirectional series resonant converter with sine-wave modulation (SWM) is proposed in this article. The single-stage power transmission, zero voltage switching (ZVS) operation, and wide voltage regulation capacity can be realized of the proposed converters. On the basis of the traditional bidirectional series resonant converter, the proposed converters are generated by reconstructing the bridge arm without adding auxiliary switches or magnetic components. After reconstruction, the proposed converters combine the traditional pulsewidth modulation (PWM) circuit and the resonant circuit. Besides, a coupled inductor is used to replace the filter inductor, resonant inductor, and transformer, which reduces the magnetic components. In addition, under the proposed SWM, the voltage is adjusted by the duty cycle with fixed frequency, and the voltage gain is independent of the load. The driving logic of the primary and secondary side are completely consistent. Especially in the half bridge structures, only one set of complementary PWM signals are required. Furthermore, in wide voltage range, the resonant current is always a sine-wave, which can simplify the voltage gain and ZVS analysis. Finally, one of the proposed topologies is analyzed in detail, and a 500 W, 250 kHz experimental prototype with 100–200 V input and 150 V output was built. The experimental results proved the effectiveness and feasibility.

A Resonant Inductor Integrated-Transformer-Based Receiver for Wireless Power Transfer Systems

Wireless power transfer charging of modern electric vehicles is complicated by widely varying charging battery pack voltages between different models. This article proposes a new resonant inductor integrated-transformer (RIIT)-based receiver. It is compact, low cost, and can adapt to different battery pack voltages without any significant change of resonant parameters. The design approach, power losses, and power transfer capacity of the proposed system are presented. In addition, methods of natural current sharing and voltage sharing among different RIITs are proposed. An LCC-LCC WPT prototype compatible with both 400 and 800-V battery pack voltages is built, and the system efficiency reaches 94% at 9.5 kW, which verifies the feasibility and performance of the proposed receiver.

Multiconstraint Design of Single-Switch Resonant Converters Based on Extended Impedance Method

The single-switch resonant converter is attractive for low-cost high-frequency power conversion applications. However, the exiting design method needs complicated derivations to meet various practical demands, and it would become impossible as the circuit order increases. This article incorporates the extended impedance method to evaluate the potential designs. The practical demands can be mathematically represented by the inequality constraints. Given the design variables, the proposed design is able to improve the steady-state performance (like the system robustness, voltage gain, load insensitivity, efficiency, current stress, and voltage stress) for the existing resonant converters. A family of Class E inverters is designed to justify the generality and validity of the proposed design. The first case is a classical Class E inverter. The EIM-based design is able to improve the system robustness under 6% parameter variation. The second case is a Class E inverter with resonant input inductor. The EIM-based design is able to offer a wider voltage gain compared to the benchmark method. The last case is a Class E inverter using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula> network. Compared to the previous design approach, the proposed method is able to find a better design point, whose light-load efficiency is improved by 5%.

A Medium Voltage Input Multiport Isolated Output DC Transformer With Power Self-Balancing and Output Fault Isolation

Medium voltage dc (MVDC) converters with multiple output ports have the challenges of series input module power balancing control and fault isolation between output ports. This paper proposes a new medium voltage input multiport isolated output dc transformer topology. The proposed topology can be extended to up to 2k-1 output ports of different voltages with k modules input connected in series. Moreover, the proposed topology has the voltage self-balancing feature of input modules since they are coupled via the balancing capacitors. Current self-balancing of all MOSFETs is also achieved, as the equivalent impedance of multiple voltage sources discharging to multiple loads is the same under the influence of the split resonant inductor. Besides, the proposed topology can limit the shorted current in the output port automatically without affecting other ports, due to the impedance of the resonant tank of the faulty port being clamped. A 2kV dc input with three output ports of 410V, 380V and 40V prototype is built to verify the feasibility of the proposed topology. The results show that the proposed topology has multiple module power self-balancing feature, and can improve the reliability of the multiport power supply systems. Therefore, it has good prospects for subsea dc power distribution systems and ship electric power distribution systems.

Efficiency Improvement for Wireless Power Transfer System via a Nonlinear Resistance Matching Network

The primary control is widely adopted to obtain a constant voltage output under a wider load range. However, for traditional full-bridge inverters under phase-shift control, due to the loss of soft switching, the system transmission efficiency will decrease rapidly. This problem can be improved by using a half-bridge inverter; however, the power transferred to receiving devices utilizing a half-bridge inverter is inadequate under a small dc load value. To solve these urge issues, a resistance matching network (RMN), constructed by a resonant inductor and capacitor, is added before the full bridge rectifier part of this paper. Owing to the nonlinear resistance conversion characteristics of the proposed RMN structure, the variation range of the equivalent AC impedance before the rectifier end can be compressed into an optimum range to enhance the poor transmission efficiency during the coils part. Simultaneously, when the DC load is small, the power capability of the whole system can be enhanced by increasing the equivalent ac load value; as a result, the insufficient power capability of the half-bridge inverter can be relieved. Finally, a 36 V output WPT system based on the proposed RMN and phase shift control is constructed. Additionally, the experimental results prove the feasibility of the theoretical analysis results.

Analisis Penstabilan Tegangan Output Generator Induksi 3 Fasa

One of the alternative generators in supplying electrical energy is a 3-phase generator made from a 3-phase slip ring induction motor, after which the rotor winding is supplied with a DC source and rotated using a prime mover. The problem arises because of the large % voltage regulation of a 3-phase generator when it is under load. This is because the induction generator has a relatively larger voltage loss when loaded with a certain load compared to a 3-phase synchronous generator. To overcome these conditions, there are several ways that can be used to stabilize the voltage from the generator, namely: setting the excitation current from the generator, setting the connection on the rotor windings (using 2 windings or using 3 rotor windings) and a combination of the two steps above. . Based on the results of experiments that have been carried out, it is known that the method of stabilizing the output voltage by setting the rotor winding connection is less effective than setting the excitation current because it turns out that the results of changing the output voltage are not too significant compared to changing the generator excitation current. In addition, it is also known that the stabilization of the output voltage from an inductive load will require a DC voltage that is greater than when under a resistive load because of the large difference in losses.

An Efficient Resonant Pole Inverter With Reliable Elimination of Switching Loss of Main Switches

The brief presents a novel resonant pole inverter for the efficient operation of the inverter. Its design process can be summarized briefly as follows: three sets of identical auxiliary circuits are respectively connected in parallel with each bridge arm of the three-phase hard-switching inverter and each set of auxiliary circuits only contains two auxiliary switches, two resonant capacitors and one resonant inductor; when the auxiliary circuits work, the current will flow through the antiparallel freewheeling diode of main switches periodically before main switches are switched on or off. Thus, the outstanding advantage of the novel inverter is that main switches can acquire zero-voltage switching-on and zero-current switching-off, making for more reliable elimination of switching loss. The brief elaborates each working state in a switching cycle. Experimental waveforms imply that switches can attain soft-switching. Moreover, the efficiency of the novel inverter achieves 99.1% at rated output power and the value marks an increase of 0.5 percentage points at the same rated output power, compared with the most recent topology in another literature. Thus, the novel inverter can have efficiency superiority over other soft-switching inverters when it is applied as the variable frequency power supply in the electric drive system.

Double-Sandwich Magnetic Coupling Structure Design for Dual-LCL Wireless Charging System in EV Applications

In the wireless charging system of EVs, the traditional single-stage LC resonance network has the issues of narrower of parameter design and small equivalent input impedance. While the composite resonant network will introduce additional resonant capacitors and inductors, which increases the system volume, cost, and reduces the efficiency. This paper proposes a design scheme of double-sandwich magnetic coupling structure with a low cross-coupling coefficient, which integrates the resonant inductors into the power transmitter and receiver, and it is designed taking the magnetic leakage and loss as constraints. A 500W prototype is built, and the comparison of experimental efficiencies between the double-sandwich and the separate magnetic coupling structures is performed. Finally, the effectiveness of the integrated design scheme is validated.

Design and analysis of isolated high step-up Y-source DC/DC resonant converter for photovoltaic applications

ABSTRACT This paper presents the design and analysis of an isolated high step-up Y-source DC/DC converter for photovoltaic systems. At high switching frequencies, the conventional impedance source converter (ISC) experiences higher switching losses. To mitigate this, a high gain soft-switched frequency-modulated Y-source DC/DC converter is proposed. Here, soft switching is implemented on the Y-source impedance converter by creating quasi-resonance during a shoot-through instant. Thus, quasi-resonance occurs by an LC resonant tank, and it is formed using a resonant capacitor and leakage inductance of a transformer. It ensures that all the active switches are turned off with zero current switching (ZCS) and the voltage stress on each switch is much lower than the output voltage with lower turn-off voltage spikes. Thus, it eliminates the need for a snubber circuit. The output voltage is regulated by frequency modulation with the ON period of all four active switches kept constant. The converter can also deliver a continuous input current (CIC) and high voltage gain with a small shoot-through duty ratio . The galvanic isolation of the converter helps to eliminate the leakage current issues and safety hazards faced by the non-isolated counterparts. The proposed topology has all the inherent characteristics of a typical impedance source DC/DC converter with higher conversion efficiency over a wide range of output loads. The proposed converter achieves 96.46% of full load efficiency. Finally, a 200W prototype is built and tested in the laboratory to verify the converter design and performance.

Dual Output and Dual-Frequency Resonant Inverter-based Induction Heating Using ADC Control

A dual output dual-frequency (DODF) resonant converter-based AC-AC induction heating (IH) by using asymmetrical duty cycle (ADC) control is presented in this paper. The proposed scheme gives two outputs with independent power control, which improves input power factor and achieves zero voltage switching (ZVS) with a wide range of operations. It includes two pairs of two half-bridge series resonant converters, each pair having one common capacitor along with various resonant frequencies. These converters are modulated with the ADC control scheme to obtain smooth operation. The proposed topology doesn’t use the DC stage; it is directly connected to the power supply to produce high-frequency AC output. With the use of direct connection, the converter components are reduced when compared to conventional converters. There will be a reduction in voltage drop, power losses, cost of the converter and which will result in improved efficiency. Simulation results are obtained from PSIM 11.1.7 software. This scheme controls two different loads with an efficiency of 98.25%.

An Improved Auxiliary Resonant Commutated Pole Inverter With Low Loss of Energy Recovery

This brief proposes an improved auxiliary resonant commutated pole inverter (ARCPI) to optimize the transmission efficiency of the inverter. During the commutation process of the inverter, main switches can acquire zero-voltage switching and auxiliary switches can acquire zero-current switching, bringing about the significant reduction of switching loss. Besides, when the resonant state suspends in each switching cycle, the surplus energy in the resonant inductor will be fed back to the energy-storage capacitor through only one auxiliary diode, making for low loss of energy recovery. This brief illustrates each working state in a switching cycle. The relative experimental waveform indicates that switches acquire soft-switching. The efficiency of the proposed inverter achieves 99.1% at rated output power. Thus, the proposed inverter can have efficiency superiority over other similar inverters.

Passive Paralleling of Multi-Phase Diode Rectifier for Wireless Power Transfer Systems

To improve the power level of a diode rectifier, a multi-phase diode rectifier can be employed to increase the current rating. This brief proposes a passive current balancing method for a multi-phase diode rectifier in a series-series compensated wireless power transfer system. For an N-phase diode rectifier, the receiver-side compensating capacitance is split into N branches, forming a parallel resonant network with the newly added parallel resonant inductors. The circulating currents can be greatly suppressed by the parallel resonant network. The resonant inductors only withstand differential-mode currents, which are small. Thus, these inductors are small and low-cost. Experimental results reveal that the proposed method can well balance the phase currents of the three-phase diode rectifier.

A New Optimization Method for Gapped and Distributed Core Magnetics in LLC Converter

LLC converter design optimization remains a challenging task for varying loads such as in battery chargers. There are numerous L-L-C combinations to choose from a design space that can satisfy the required voltage gains of the application. An accurate magnetic model is essential to optimally size the passive components according to the application needs. This paper provides a new design tool for gapped core magnetics to optimize the transformer and resonant inductor in LLC converters. Unlike conventional design algorithms, the proposed algorithm considers multiple distributed cores and selects the optimal magnetic flux density by minimizing a penalty function that includes power loss, cost and volume of the magnetic components using Big-Bang Big-Crunch Algorithm. The gapped core transformer and inductor design equations have been verified in Ansys Maxwell and Simplorer co-simulation environment for a 3700W 48V LLC and calculated power loss have been compared with experimental results. For the given L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> and L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> pair of 37.52 μH and 9.38 μH, the proposed magnetic model designed a transformer with two-distributed cores, each one exhibiting a magnetizing inductance of 17.73 μH and leakage inductance of 0.7 μH on a EE422120 with 3F36 material. The total power loss of the transformers are measured as 12.44 W on a 3700 W prototype switched at 350 kHz.