Frequency Inverter Research Articles

Design of a Model Predictive Controlled Single‐Stage Boost Assisted High Frequency Inverter for Wireless EV Charging System

ABSTRACTThis article proposes a new Wireless EV charging system with a single stage boost assisted flyback (SSBAFB) inverter. Also, this presents Model predictive (MP) control for the proposed system. The key merits of the proposed SSBAFB inverter are better efficiency (boost stage optimizes the energy transfer), cost‐effectiveness, possibility of integrating with renewable sources. The significant features of MP control are predictive performance, better dynamic response, multi‐objective control, robustness, and many more. In the literature, two MP controls were employed, one on the transmitter side and the other on the receiver side for controlling efficiency and load regulation respectively. The proposed MP‐controlled SSBAFB inverter‐based WPT system utilizes single MP control, which can attend to both load regulation and efficiency enhancement. To validate the performance of the proposed WPT system, a 3.3 kW laboratory model has been developed. The steady‐state and dynamic performance of the proposed system under closed‐loop control exhibits better performance. The comparison of the proposed converter with possible converter topologies shows that the proposed converter stands out in producing high efficiency. A comparative study of the proposed MP controller with other conventional controls proves that the proposed MP controller offers better steady‐state stability and fast dynamic responses.

Modelling Analysis and Characteristics of Multi-Level Inverter for Integrating Solar PV System to Grid

This paper investigates the implementation of a cascaded H-bridge multi-level inverter in a single-phase grid-connected solar photovoltaic (PV) system to address harmonic distortion challenges in DC-to-AC power conversion. The primary objective is to enhance power quality and system efficiency by leveraging the inverter's ability to reduce harmonics through power sharing and a lower switching frequency. A Simulink model is developed to evaluate the proposed system's performance, incorporating a unipolar Pulse Width Modulation (PWM) control strategy and an LCL filter for effective harmonic mitigation. The system employs Maximum Power Point Tracking (MPPT) based on the Perturb and Observe (P&O) algorithm, combined with Synchronous Reference Frame Theory-Phase Disposition PWM (SRFT-PDPWM) for optimal control. The proposed inverter ensures precise synchronization between the grid and inverter frequencies, achieving a Total Harmonic Distortion (THD) below 5%. Simulation results demonstrate the system's robust responsiveness to variations in solar irradiance, with increased irradiance leading to further reductions in THD and improved power quality. These findings validate the proposed inverter's capability to deliver high-quality, efficient power under varying environmental conditions, aligning with global objectives for integrating clean and sustainable energy into utility networks.

Development of a Low-Cost Automated Injection Molding Device for Sustainable Plastic Recycling and Circular Economy Applications

In response to the critical demand for innovative solutions to tackle plastic pollution, this research presents a low-cost, fully automated plastic injection molding system designed to convert waste into sustainable products. Constructed entirely from repurposed materials, the apparatus focuses on processing high-density polyethylene (HDPE) efficiently without hydraulic components, thereby enhancing eco-friendliness and accessibility. Performance evaluations identified an optimal molding temperature of 200 °C, yielding consistent products with a minimal weight deviation of 4.17%. The key operational parameters included a motor speed of 525 RPM, a gear ratio of 1:30, and an inverter frequency of 105 Hz. Further tests showed that processing temperatures of 210 °C and 220 °C, with injection times of 15 to 35 s, yielded optimal surface finish and complete filling. The surface finish, assessed through image intensity variation, had a low coefficient of variation (≤ 5%), while computer vision evaluation confirmed the full filling of all specimens in this range. A laser-based overflow detection system has minimized material waste, proving effective in small-scale, community recycling. This study underscores the potential of low-cost automated systems to advance the practices of circular economies and enhance localized plastic waste management. Future research will focus on automation, temperature precision, material adaptability, and emissions management.

High Frequency Inverter with Fuzzy Logic Controller for Portable Induction Heater

The development of technology today makes humans strive to save natural resources and switch to alternative energy. For reasons of saving energy, saving costs, easy to use, and having a high level of safety, induction heaters can be used as an alternative to overcome these problems. Induction heaters can generate heat through the process of electromagnetic induction when cookware made of metal is brought closer. In this process the coil is supplied with alternating electric current from a high frequency inverter which then induces the cookware with metal material to cause heat. The heat in the induction heater will be regulated through the switching frequency of the high-frequency inverter which gets its voltage source from a 24V battery and increases the voltage to 48V. This induction heater is designed to maintain the setpoint temperature 70°C and 100°C using fuzzy logic control. From the test results it can be seen that the fuzzy logic control can reach a setpoint temperature of 70°C within 20 minutes and after being disturbed the fuzzy logic control can maintain the setpoint temperature with an error percentage of around 0.14% - 0.29%. Meanwhile, the setpoint temperature of 100°C can be achieved within 35 minutes and after being disturbed the fuzzy logic control can maintain the setpoint temperature with an error percentage of around 0.14% -0.9%.

Design and implementation of wireless power transfer device

Abstract. Magnetic coupled resonant radio energy transmission (WPT) technology utilizes the coupling of the magnetic fields of the transmitting and receiving coils and wirelessly transmits energy through electromagnetic induction, greatly expanding the applications of power equipment in special environments. The technology uses the magnetic field coupling between the transmitting coil and the receiving coil to realize the wireless transmission of energy through electromagnetic induction. This method breaks the limitation of traditional wire transmission and greatly expands the application potential of power equipment in various special environments. In this paper, an efficient, stable and long-distance wireless charging device is designed and realized. In order to improve transmission efficiency, two-coil configuration with series-series structure is adopted, and its equivalent circuit model is established by circuit theory and Kirchhoff's law. Therefore, a new radio energy transmission device based on single chip microcomputer is designed, including PWM signal generator, level matching circuit, high frequency inverter circuit and other key parts. Expressions for transmission efficiency and output power are derived from equation analysis and power-on experiments performed on a physical device. In addition, the effects of transmission frequency, load impedance and transmission distance on the performance are investigated.

Calculation of power losses in a frequency inverter

Calculation of power losses in a frequency inverter

Analytical Model of Maximum Operating Frequency of Class-D ZVS Inverter with Linearized Parasitic Capacitance and any Duty Ratio

Analytical Model of Maximum Operating Frequency of Class-D ZVS Inverter with Linearized Parasitic Capacitance and any Duty Ratio

Experimental Evaluation of Acoustical Materials for Noise Reduction in an Induction Motor Drive

Electric propulsion motors are more efficient than internal combustion engines, but they generate high-frequency tonal noise, which can be perceived as annoying. Acoustical materials are typically suitable for high-frequency noise, making them ideal for acoustic noise mitigation. This paper investigates the effectiveness of three acoustical materials, namely, 2″ Polyurethane foam, 2″ Vinyl-faced quilted glass fiber, and 2″ Studiofoam, in mitigating the acoustic noise from an induction motor and a variable frequency inverter. Acoustic noise rates at multiple motor speeds, with and without the application of acoustical materials, are compared to determine the effectiveness of acoustical materials in mitigating acoustic noise at the transmission stage. Acoustical materials reduce acoustic noise from the induction motor by 5–14 dB(A) at around 500 Hz and by 22–31 dB(A) at around 10,000 Hz. Among the tested materials, Studiofoam demonstrates superior noise absorption capacity across the entire frequency range. Polyurethane foam is a cost-effective and lightweight alternative, and it is equally as effective as Studifoam in mitigating high-frequency acoustic noise above 5000 Hz.

MEDIUM-POWER DRIVE INSTALLATIONS BASED ON TRIPLE VOLTAGE SOURCE INVERTERS ADJUSTED BY ALGORITHMS OF SYNCHRONOUS MULTI-ZONE PWM

This paper presents short overview of the development and dissemination of specialized schemes and algorithms of space-vector-based synchronous multi-zone pulsewidth modulation (MZ PWM) for control of triple inverters of the medium-power variable speed drives characterized by relatively low switching frequency of inverters. It insures providing synchronization and symmetry of the basic voltage waveforms in triple-inverter-based configurations of drive installations on the base of standard voltage source inverters (VSIs). It assures also minimization of magnitudes of even-order harmonics and undesirable subharmonics in spectra of the basic voltages of drive installations, leading to reducing of losses in the corresponding apparatuses and to increasing of its efficiency. Examples of application of the basic techniques of multi-zone PWM for regulation of three typical structures of triple-VSI-based medium-power motor drives are presented. Modeling and simulations give a behavior of drive installations based on triple inverters adjusted by algorithms of synchronous MZ PWM. References 12, figures 11, table 1.

Implementation and Analysis of an Efficient Soft-Switching Battery Wireless Charger with Re-Configurable Rectifier

To significantly reduce switching loss of the high frequency inverter in battery wireless charger (BWC), improve the soft-switching stability and system reliability, a novel soft-switching BWC with low loss auxiliary network and re-configurable rectifier is presented. The presented soft-switching BWC can implement the smooth switching between constant current mode (CCM) and constant voltage mode (CVM) without frequency switching and relays, which is beneficial to enhancing the system stability. With the help of a novel low energy consumption auxiliary circuit, the power switch tubes in the H-bridge inverter can implement zero-voltage soft switch-ON and zero-current soft switch-OFF in the full range, completely eliminating switching loss of the inverter. The proposed scheme can enhance the system efficiency while refraining from the soft-switching range limitation and soft-switching failure caused by the system parameter perturbation. Finally, a 1-kW soft-switching BWC principle prototype is developed to validate the effectiveness and correctness of the proposed scheme.

Design of A GaN Based High Frequency Inverter for Electrosurgery

Electrosurgery performs cutting and coagulation procedures using high energy and high frequency electric current. It reduces bleeding during surgical interventions, shortens the operation time and accelerates the healing process. In this study, a GaN based high frequency full bridge class DE resonant inverter design is proposed for use in electrosurgery. The proposed inverter provides AC voltage at high frequencies and the switches operate with ZVS (Zero Voltage Switching) at low voltage stress. In addition, the use of GaN elements provides high efficiency and high-power density. The operating frequency is selected as 500 kHz for three different cutting modes of electrosurgery. After the technical analysis and simulation studies of the high frequency class DE resonant inverter, an experimental setup was designed and implemented in a laboratory environment. The efficiency performance over a variable load range is analysed. Finally, pure cutting, blend and coagulation modes are tested on the different loads, potato - chicken breast - liver, simulating real tissue. On the potato load for pure cutting mode, the output voltage is 39.9 V and the output current is 0.7 A while an efficiency of 35%.

Renewable energy resource integrated multilevel inverter using evolutionary algorithms

In this paper, with the development of an intelligent power system idea, sustainable energy sources were increasingly deployed, including transmission and distribution systems networks. As a result, optimal use of cascaded H-bridge inverter topologies (MLIs) and power distribution operations is critical for long-term power generation. Traditionally, selective harmonics reduction models must be performed to achieve the optimal switching frequency of multilevel inverters. This research aims to determine the switching frequency for wind-incorporated multilevel inverters to reduce overall harmonic components used in grid applications. This research adds towards the best possible solution by employing multiple newly established adaptive optimization techniques: MNSGA-II and salp swarm. The well-known genetic algorithm and particle swarm optimization are used for the wind-tied multilevel inverters optimization issue. Seven-level, eleven-level, and fifteen-level MLIs were employed to reduce overall harmonic distortion. The reliability and convergence rate of simulated data with various modulation indices for seven-, eleven-, and fifteen-level MLIs are obtained and compared. Models are developed based on MATLAB Simulink and are used to validate quantitative measurements.

Research on strategy of load-side resonant soft-switching inverter based on interconnection and damping assignment-passivity based control

Soft-switching technologies can effectively solve the problem of switching losses caused by increasing switching frequency of grid-connected inverters. As a branch of soft-switching technologies, load-side resonant soft-switching is a hotspot for applications of high-frequency inverters, because it has the advantage of achieving soft-switching without using additional components. However, the traditional PI control strategy based on the linear model is prone to destabilization and non-robust dynamic performance when large signal perturbation occurs. In this paper, a novel Passivity-Based Control (PBC) method is proposed to improve the dynamic performance of load-side resonant soft-switching grid-connected inverter. Besides, the model based on the Port Controlled Hamiltonian (PCH) model of the soft switching inverter is carried out, and the passivity-based controller is designed based on the established model using the way of interconnection and damping assignmentpassivity based control (IDA-PBC). Both stable performance and dynamic performance of the load-side resonant soft-switching inverter can be improved over the whole operating range. Finally, a 750 W load-side resonant soft-switching inverter simulation model is built and the output performance is compared with the traditional PI control strategy under stable and dynamic conditions. The simulation results show that the proposed control strategy reduces the harmonic distortion rate and improves the quality of the output waveforms.

Development of a distributed group control strategy for pumping well groups connected by multisource DC microgrids

Due to the alternating loads on pumping units and the integration of new energy sources, multisource DC microgrid pumping unit well groups experience increased fluctuations in voltage and power as well as superimposed peak and valley values. This work presents a distributed control strategy for pumping unit well groups on a multisource DC microgrid based on the weighted moving average algorithm. A centralized control program is implanted in the RTU of the single-well controller of each pumping unit, and communication with each well is realized via SCADA and multicast communication, resulting in a distributed well group system. The real-time power values of the pumping well group are calculated by grouping the power values, and each group is weighted using the total power fluctuation threshold of the well group as the control target. Then, a weighted moving average algorithm is used to predict the next power value and form a table of predicted real-time power spectra. According to the power values in the community power spectrum table, the inverter frequency is proportionally adjusted downwards to reach the power peak before deceleration; after the power peak is crossed, the frequency is increased in the same way to reach the power valley before acceleration. Finally, the peak and valley power values of the bus system level off and further learn to reach the set impulse; ultimately, a stable impulse is formed. In laboratory testing and field application in the Shengli Oilfield XIN-11 block, the group control software module effectively suppressed the active power peak and valley values and voltage fluctuations of the bus system, the active power fluctuation rate range decreased by more than 70%, and the DC bus voltage fluctuation range decreased by more than 80%; moreover, the active power decreased by approximately 6% without additional hardware costs.

Development of method for frequency regulation of output current in high-voltage transformerless resonant chargers of capacitive energy storage devices

The object of research is high-voltage systems of electric discharge installations for various technological purposes. The work reports solving the problem of enabling the rate of charging of a capacitive energy storage, set by the requirements of a certain high-voltage technology. The quantitative characteristics of the deviation of the output current of the resonant inverter from the set stabilized value when changing the switching frequency of inverter switches in the range of output voltage change from 0 to 20 kV were determined. Using the Fourier transform of the rectangular input voltage, the frequency regulation possibility of the output current of the charger for capacitive energy storage devices was analyzed. Estimation dependences of the output current of resonant inverter on the load resistance and frequency deviation from resonant frequency were derived. These dependences could be used to implement frequency control over the switching inverter transistors, with the help of which the given effective value of the output current of the resonant inverter is obtained. A method of frequency regulation of the output current in high-voltage transformerless resonant charging devices of capacitive energy storage devices has been developed. Special feature of this method is that it is based on the frequency dependence of reactive resistances of the inductance and capacitance of the resonant circuit connected in series. Owing to that, it makes it possible to adjust the switching frequency of the inverter’s power switches depending on the relative resistance of the load and the specified growth rate of the capacitive energy storage voltage. The results reported here could be used in the design of benches for testing the electrical strength of high-voltage cables, as well as for the construction of high-voltage transformerless chargers in systems of electric discharge impulse processing of materials

Research on Analysis and Suppression Methods of the Bearing Current for Electric Vehicle Motor Driven by SiC Inverter

The silicon carbide (SiC) inverter brings great advantages to the motor drive systems of new energy vehicles; however, severe challenges to the bearings also happen. The high dc bus voltage and switching frequency of SiC inverter can increase the discharge frequency and energy when the bearing grease film collapses. As a result, the bearing suffers severe electric corrosion, and the service life of the motor drive system can be shortened. In this paper, the characteristics of common-mode voltage and bearing voltage are analyzed, firstly under space vector pulse width modulation (SVPWM). After that, the common-mode equivalent circuit model of the motor drive system is established. The frequency characteristics of bearing voltage are revealed, and the safe working area is determined. Then, the frequency characteristics of bearing voltage and current are verified based on IGBT and SiC inverters in experiments. After that, by designing a common-mode filter, the bearing voltage and current are significantly attenuated. Furthermore, the active zero state PWM (AZSPWM) is adopted to reduce the common-mode voltage from the inverter. At the same time, combined with the common-mode filter, the bearing voltage and current are further reduced. The experimental results show that the switching frequency has a decisive effect on the amplitude of bearing voltage and current. The bearing voltage can be attenuated to around half of the reference bearing voltage by using the common-mode filter and AZSPWM strategy, respectively. The combination of the common-mode filter and AZSPWM strategy can reduce the bearing voltage to around one-fourth of the reference bearing voltage, which can effectively reduce the breakdown time and discharge energy of the grease oil film.

Determination of Circuit Parameters in Domestic Induction Heaters by Analytical Solution Method

Domestic induction heaters provide efficient, fast, and safe heating. Variable circuit parameters in domestic induction heaters show different characteristics depending on the type of parts used for heating and the area they cover on the heating coil. For this reason, resonant frequency, maximum inverter current, and quality factor parameters of the induction heaters also change. In this study, the tests of the domestic induction heater circuit with series resonant inverter were carried out with various of workpieces diameters. The resonant frequency and maximum inverter current parameters obtained from the experimental studies, curve fitting process was performed in the MATLAB and a function on related with heater parameters was derived. By using the obtained functions, the resonant frequency and maximum inverter current of the materials in the workpieces with intermediate diameters were calculated with high accuracy and compared experimentally. Analytical calculations and experimental results confirmed each other with an accuracy and it was shown that induction heater circuit parameters could also be calculated by analytical solution method.

MPPT control of a solar pumping system based five-phase impedance source inverter fed induction motor.

This paper presents a control method for a system composed of a photovoltaic (PV) array, five-phase impedance source inverter, five-phase induction motor and centrifugal pump. This method is based on controlling the motor speed to control the pump power as the insolation level or temperature change to attain the maximum power extraction from the PV-array. The motor speed is controlled by using artificial neural network (ANN) which is trained to provide the desired inverter frequency and modulation index at any insolation level and temperature to attain the maximum PV operating power. The data of the neural network are based on the operation of the induction motor at constant air gap flux and perturb and observe method for maximum power point tracking. Simulation results are obtained using MATLAB Simulink to verify the proposed control method.

An Approach to Decrease Transient Circulating Current of VSIs in Islanded Microgrid

This paper investigates new methods of transient power sharing in parallel inverters. In order to obtain a faster transient response, a control unit is added to conventional droop method. In this control unit, the nominal frequency and voltage of inverters are changed to control the circulating current during transients. In this wireless method, the amount and period of circulating current between inverters are reduced. A detailed analysis shows that the proposed method has a superior transient performance and power sharing in comparison with the other methods. The simulation results indicate the accuracy of the proposed method.

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 (<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.