kHz Switching Frequency Research Articles

Design and Implementation of 3 kW All-SiC Current Source Inverter

In this paper, the optimal design and implementation of a silicon-carbide (SiC) power semiconductor-based current source inverter (CSI) with a power rating of 3 kW focusing on high power density are discussed in detail. The proposed methodology integrates analytical and numerical techniques to optimize the design of passive components, including filter capacitors and the DC-link inductor, and provides a comprehensive analysis of power semiconductor losses. The losses in the DC-link inductor as well as in the output capacitor are strongly dependent on the modulation strategy. Semi-analytical loss models are therefore derived for the most advanced modulation strategy, which are subsequently used to increase volumetric power density. The theoretical findings are experimentally validated using an ultra-compact, high-efficiency 3 kW three-phase CSI prototype operating at up to 100 kHz switching frequency. The experimental results confirm the efficiency of the proposed design and demonstrate its potential for high-power, compact drive applications.

Integrated photonic MEMS switch for visible light.

Visible-light integrated photonics serve applications inaccessible to conventional (C- and O-band) silicon photonics, including trapped-ion and neutral atom quantum experiments, biophotonics, and displays. Despite demonstrations of increasingly advanced functionalities and levels of integration, the development of low-power, monolithically integrated, visible-light switches and phase shifters remains an outstanding challenge. Here, we demonstrate an integrated photonic, electrostatic MEMS-actuated Mach-Zehnder interferometer optical switch for the visible spectrum. The device operated with an extinction ratio of 7.2 dB and optical loss of 2.5 dB at a wavelength of 540 nm. The measured 10-90% rise (fall) times were 5 (28) µs, and a low static power dissipation of about 0.5 nW was achieved. The dynamic power dissipation at a 30 kHz switching frequency was estimated to be < 70 µW.

Bridgeless Power Factor Correction Flyback Rectifier Using a Novel Integrated Transformer

ABSTRACTThis study proposes a novel integrated transformer structure with simple circuit configuration and miniaturized magnetic components. In a bridgeless flyback rectifier, two flyback converters operate corresponding to the polarity of the AC input, requiring two transformers. This paper proposes a novel winding structure that realizes zero coupling co‐efficient between two sets of windings. This enables the integration of two transformers into a single transformer, preventing their flyback operations from interfering with each other. The integrated transformer has approximately 16% lower volume compared to that of conventional transformers. The proposed integrated transformer was built, evaluated, and verified by designing a 75 W‐bridgeless flyback rectifier with 100 kHz switching frequency.

Efficient high step‐down converter with soft switching and minimal components

AbstractThis paper presents a novel two‐switch high step‐down converter based on the conventional Ćuk converter. The proposed converter features lower gain and higher efficiency due to reduced switching and conduction losses. Notably, it enables zero current switching turn‐on for switches without requiring additional components, enhancing its efficiency. The low voltage stress on the switches significantly impacts efficiency. Additionally, its simple topology reduces the component count, further improving efficiency. Zero current switching turn‐off condition for the diode effectively addresses reverse recovery problem. To validate its performance, a prototype operating at 200 W output power, 300 V input voltage, 24 V output voltage, and 40 kHz switching frequency is implanted.

An extendable switched‐capacitor based three‐phase multilevel inverter with boosting capability

AbstractThe increasing demand for integrating renewable energy sources necessitates inverter topologies with boosting capabilities. Using inverters with boosting capability and a low number of components to integrate renewable energy sources can reduce costs. This study describes a three‐phase multilevel inverter based on extendable switching capacitors. The use of voltage‐doubling modules permits the development of the inverter's capability. By increasing the number of doubling modules, the number of output voltage levels and boost factor are increased. Furthermore, the study introduces and implements a line voltage‐based pulse width modulation approach developed for the proposed inverter. The operation of the proposed multilevel inverter, along with the pulse width modulation scheme, common mode voltage, and power loss analysis are thoroughly discussed. Additionally, a comparative analysis is provided; highlighting the advantage of reducing the number of power switches in the proposed three‐phase inverter compared to other existing topologies. Finally, a laboratory prototype is developed, operating at a 4 kHz switching frequency and with a 120 V DC‐link voltage. The experimental results corroborate the efficiency and performance of the proposed multilevel inverter, thereby validating its practical applicability.

Design of a high voltage gain converter using coupled inductor with reduced voltage stress for photovoltaic energy based systems

This paper presents the design and analysis of a high voltage gain converter utilizing a coupled inductor with reduced voltage stress, specifically for photovoltaic energy-based systems. The proposed converter employs a two-winding coupled inductor and voltage multiplier cells to achieve an increase in output voltage while mitigating voltage stress across semiconductor components. Additionally, the voltage multiplier cells function as voltage clamps for the power switch, further enhancing the converter's performance. The converter features a single switch design, which simplifies control, reduces cost, and improves reliability. Key advantages of the converter include a low component count, a common ground between input and output ports, and high efficiency. The converter's performance is thoroughly investigated through mode analysis and steady-state analysis. Comparative evaluations with similar converters are conducted to highlight the benefits and performance of the proposed design. To validate the theoretical analysis, a 125 W prototype with 26 V input and 200 V output voltages operating at a 50 kHz switching frequency is developed, and experimental results are presented, demonstrating the effectiveness and practicality of the proposed high voltage gain converter.

Comparison of the performance of Si, SiC, and GaN based switching elements in high gain DC-DC boost converter

Abstract In this study, Si, SiC, and GaN based semiconductor switching elements to be used in the design of new generation high gain DC-DC converters are compared. Each switching element is tested at different frequencies and different pulse period ratios. The efficiency and output voltage of the high gain boost converter are analyzed in detail according to the switching element used. The amplifiers have been investigated at 50 kHz and 5 MHz switching frequencies. The results show that the converter using GaN-based MOSFET is more efficient than converters using other MOSFETs and reaches the highest efficiency at 200 kHz switching frequency. The proposed converter achieves 91.68% efficiency and 2.66 voltage gain at 0.3 pulse period rate, 94% efficiency and 3.78 voltage gain at 0.5 pulse period rate and 93.94% efficiency, and 6.33 voltage gain at 0.7 pulse period rate. Thus, it is understood that when GaN based MOSFETs are used in high gain DC-DC converters, higher gain and higher efficiency are achieved.

LCL filter design and experimental response analysis for a SiC inverter

In this paper, an LCL filter for a 20-kW SiC power inverter with a 25 kHz switching frequency is proposed and assessed. The transfer function without neglecting the network effect is considered. The optimal value of the damping resistor is evaluated to minimize losses while maintaining power quality and device stability. Finally, the harmonic content produced by the SiC inverter is experimentally measured to verify the effectiveness of the LCL filter.

A non-isolated synchronous buck DC-DC converter, ZVS topology under CCM and DCM conditions

A non-isolated synchronous buck DC-DC converter, ZVS topology under CCM and DCM conditions

A new‐high efficiency non‐isolated DC‐DC converter with combination of step‐up techniques

SummaryIn this paper, a new high‐step‐up DC‐DC converter without any coupled inductors or transformers is introduced. The structure of the introduced converter consists of two boost techniques, namely, switched inductor and switched capacitor, used simultaneously. The drawbacks of each technique are mitigated according to the proposed structure and the introduced control method. Therefore, the main contribution of the introduced converter is its ability to use boost techniques while avoiding high input current ripples and inrush currents in the path of semiconductor devices. Thus, there is no need for an auxiliary inductor. Additionally, the number of required components is low, and it benefits from a common ground, which are advantages of this converter in terms of economy and reliability. Another advantage is the high efficiency of the proposed converter in comparison with recent topologies, making it suitable for renewable energy applications such as photovoltaic (PV) systems and fuel cell applications. The proposed converter has been implemented in a laboratory to verify its performance. It operates at 94.51% efficiency with a 200 W output power, a 40 kHz switching frequency, a 40 V input voltage, and a 240 V output voltage.

Modeling, Analysis, and Winding Loss Calculation of Different Litz and Solid Wire on Coupled Inductor in DC–DC Cuk Converter for DCM

In this article, the coupled inductor is designed using a litz wire, an enameled litz wire, and a solid wire separately. All the coupled inductors wound with litz and solid wires are tested in a Cuk converter operated in DCM with a 25 kHz switching frequency for 15 W power, and winding losses of each wire, including proximity and skin effect loss, are calculated analytically without using any software, by using different techniques presented in literature, and the results are compared. Also, state-space modeling of the converter using a coupled inductor for DCM is derived as a contribution of the article because such a modeling is not derived for the Cuk converter in the literature. Thanks to the applications, inductor currents, switch voltage, input–output voltage, and output current are measured for coupled inductors with different wires. In addition, FEM simulation and co-simulation of all coupled inductors are realized, and the results obtained by applications are verified by them. Besides, it is shown that while the number of turns is the same, increasing the bundle of wires increases efficiency and inductance, reducing the window area and coupling coefficient.

Efficiency improvement with intelligent control of induction motor drives

The energy saving potential of induction motor drives is investigated. Two new aspects are identified, a multilevel frequency inverter and the speed control with variable rotor flux. Multilevel inverters with new wide-bandgap semiconductors for low voltage electrical drives (&lt;1000 V) reduce power semiconductor losses, voltage transients at the motor windings and harmonic losses in the cables. The power semiconductor losses of a two-level and a three-level inverter are compared. At 20 kHz switching frequency the losses of the three level inverter are 38 % lower compared to the two-level inverter. Another efficiency improvement potential is the speed control with variable rotor flux instead of commonly used constant flux. The rotor flux for maximum efficiency depends on the actual load and speed of the motor. The optimal rotor flux for maximum motor efficiency can be pre-calculated for each load and speed and implemented as reference value for rotor flux control in the frequency inverter. The maximum efficiency improvement with an 11 kW induction motor at small load reaches 35 % in motor and 45 % in generator operation mode. An increase in efficiency can be reached below 2/3 of rated torque in the whole speed range from 10 to 100 Hz.

Experimental Evaluation of a 2 kW/100 kHz DC–DC Bidirectional Converter Based on a Cuk Converter Using a Voltage-Doubler Concept

This paper presents a theoretical analysis of steady-state operation, control-oriented modeling for voltage control, and the experimental results of a DC–DC bidirectional converter based on a Cuk converter using a voltage-doubler concept. Due to the voltage-doubler concept, the voltage stress across semiconductors is reduced when compared with the conventional Cuk converter; this allows for the use of semiconductors with reduced drain–source on-resistance. Moreover, due to the input and output current source characteristics, the converter presents advantages, such as draining/injecting currents on both sides with low-ripple currents. Furthermore, the theoretical analysis is verified by experimental results obtained from a proof-of-concept prototype designed with a 250 V input voltage, a 360 V output voltage, 2 kW rated power, and 100 kHz switching frequency.

Investigating PWM-Induced Iron Losses: Measurements and Estimation Models up to 350 kHz Switching Frequency

Investigating PWM-Induced Iron Losses: Measurements and Estimation Models up to 350 kHz Switching Frequency

A Zero-Voltage-Transition H5-Type Transformerless Photovoltaic Grid-Connected Inverter

Efficiency and leakage current are two major issues for transformerless grid-connected inverters (TLI). Soft-switching technologies can reduce switching losses and be applied in TLIs. Herein, a zero-voltage-transition H5 type (ZVT-H5) inverter with soft turn-on and turn-off transitions of high-frequency main switches is derived from basic resonant tanks. Compared with the hard-switching H5 (HS-H5) inverter, the conversion efficiency of ZVT-H5 is significantly improved. Moreover, the reverse recovery problem of freewheeling diodes is alleviated under the operation of the auxiliary resonant network. Meanwhile, a diode clamping branch is employed to achieve constant common-mode characteristic for the ZVT-H5. The construction process of the proposed topology is described, and the operation principle of the auxiliary resonant network is analyzed. Moreover, the resonant parameter design of ZVT-H5 and its circuit performance are discussed in detail. Finally, the experimental results of a 3-kW prototype at 100 kHz switching frequency are provided to verify the effectiveness of the ZVT-H5.

A non‐isolated single‐switch ultra‐high step‐up DC–DC converter with coupled inductor and low‐voltage stress on switch

AbstractThis paper presents a non‐isolated single‐switch ultra‐high step‐up (UHSU) DC–DC converter with a three‐winding coupled inductor (CI) which is utilized to achieve ultra‐high voltage gain with a small amount of duty cycle leading to low conduction losses of the power switch and higher efficiency. The voltage gain of the suggested UHSU converter is adjusted by two methods: the duty cycle of the power switch and the three‐winding CI turn ratio, therefore enhancing the design flexibility of the suggested converter. Due to the utilization of the passive clamp circuit in the structure of the proposed converter, it is possible to select a power switch with low voltage rated and small ON‐state resistance, further enhancing the converter efficiency. The operation modes are discussed in detail and to clarify the salient features of the proposed converter, a comparison with other configurations is provided. Finally, to accredit the performance of the proposed converter, a 150‐W laboratory archetype with an input and output voltage of 20 and 300 V, respectively, at 50 kHz switching frequency is fabricated.

A status pre-matching method for the real-time simulation of power electronic converters

A status pre-matching method for the real-time simulation of power electronic converters

Average current mode controller for bridgeless PFC SEPIC converter with second-order model reduction operated in continuous conduction mode.

This paper proposes an average current mode controller (ACMC) for a single-phase bridgeless power factor correction (PFC) circuit using a single ended primary inductor converter (SEPIC) via second-order model reduction. The superiority of the proposed controller is PFC accomplished at power up to 350 W with high efficiency via the second-order model reduction. The design and implementation of ACMC on the converter operated with continuous conduction mode (CCM) is explained in detail. ACMC forces input current to follow sinusoidal current reference at different power levels and sustain high power factor (PF). The proposed controller is designed based on the theoretical analysis operation of the circuit. For verification, MATLAB/Simulink simulations are carried out and validation through an experiment test rig for 110-220 Vrms input, 100 Vdc/ 350 W output prototype at 20 kHz switching frequency. It is proven that the proposed controller strategy accomplishes high PF, high efficiency and conformity with the simulation.

Isolated Zvs-Pwm DC-DC Converter Based on the Variable Capacitor Technique

This paper introduces a new static power conversion principle, based on the variable capacitance of a capacitor arrangement. As an example of the proposed technique, an isolated ZVS-PWM dc-dc converter topology is proposed. Circuit operation and theoretical analysis, with emphasis on the soft-commutation process, are included in the paper. To validate the theoretical analysis and verify the operation of the converter, a proof-of-concept experimental prototype with 960W power rating, 400 V input voltage, 48 V output voltage and 100 kHz switching frequency was designed, constructed and tested in a laboratory. An additional attribute of the proposed technique is the reduction of the voltage across the power semiconductors to two-thirds of the dc bus voltage, when the duty cycle is equal to 0.5. The proposed technique can be extended and used to generate several other topologies of isolated and nonisolated dc-dc converters.

Easy-to-install battery storage based residential power supply with contactless power transfer

Easy-to-install battery storage based residential power supply with contactless power transfer