Conventional Full-bridge Inverter Research Articles

Modified switching control of SRM drives for electric vehicles application with torque ripple reduction

The switched reluctance motor (SRM) offers extensive prospects, particularly within the realm of electric vehicles (EVs). Its robust construction, wide speed range, high torque density, and efficiency provide significant advantages that surpass other motors. Nonetheless, controlling these motors is more intricate when compared to conventional DC brushed or AC motors. This complexity arises due to the non-linear inductance characteristics of SRMs, resulting in undesirable effects like torque ripple, vibrations, and noise. Using the conventional full-bridge inverter, three switching approaches are highlighted for various operating modes of an EV. This aims to reduce costs and the number of switching pulses, leading to a more compact system, elimination of dead time, and switching losses. The MATLAB/Simulink platform was utilized to examine the operational effectiveness of a three-phase 6/4 poles SRM drive. Additionally, this paper focuses on mitigating torque ripple concerns by employing an adaptive neuro-fuzzy inference system (ANFIS) controller that has better efficiency and superior responses compared to conventional controllers such as fuzzy logic control (FLC) and proportional integral (PI) control. The results of the simulation encourage the practical implementation of the system, which is the next step in the author’s research.

Design of PLL Controller for Resonant Frequency Tracking of Five-Level Inverter Used for Induction Heating Applications

In this work, the phase lock loop PLL-based controller has been adopted for tracking the resonant frequency to achieve maximum power transfer between the power source and the resonant load. The soft switching approach has been obtained to reduce switching losses and improve the overall efficiency of the induction heating system. The jury’s stability test has been used to evaluate the system’s stability. In this article, a multilevel inverter has been used with a series resonant load for an induction heating system to clarify the effectiveness of using it over the conventional full-bridge inverter used for induction heating purposes. Reduced switches five-level inverter has been implemented to minimize switching losses, the number of drive circuits, and the control circuit’s complexity. A comparison has been made between the conventional induction heating system with full bridge inverter and the induction heating system with five level inverter in terms of overall efficiency and total harmonic distortion THD. MATLAB/ SIMULINK has been used for modeling and analysis. The mathematical analysis associated with simulation results shows that the proposed topology and control system performs well.

A New Converter Topology with PV/Battery Hybrid System with Energy Management Control Strategy

This Paper aimed at developing a standard procedure for the design of large-scale institutional grid-connected solar PV systems using the roofs of buildings and car parks. Grid-connect PV systems with battery back-up (sometimes referred to as uninterrupted power supply or hybrid solar PV systems) are becoming increasingly popular. Grid-connected systems do not need batteries which reduces considerably initial capital costs and energy costs. For a comparable load, grid -tied systems use smaller PV arrays than stand-alone systems. In order to address this issue, a two-stage stand-alone scheme consisting of a novel transformer coupled dual-input converter llowed by a conventional full-bridge inverter is proposed. The proposed converter can realize maximum power point tracking and battery charge control while maintaining the proper voltage level at the load terminal. A suitable control strategy for the proposed converter devised for manipulating the converter to realize the first two aforementioned objectives, while the third objective is achieved by employing a conventional proportional integral (PI) controller to control the output voltage of the five level inverter through sinusoidal pulse width modulation

Dual-Buck Full-Bridge Converter With Soft-Switching Characteristics for High-Precision Applications

The output distortion of conventional full-bridge inverter is present due to the required switch blanking time. Dual-buck full-bridge inverter (DBFBI) does not experience blanking time problems but requires a bias current to make the inductors operate in continuous conduction mode (CCM) for better output waveform with interleaved switching. The existence of bias current will cause dc-biased magnetization of the inductors and make them easy to saturate. To overcome this problem, the volume of inductors must be sufficiently large to ensure that there is no saturation in CCM of inductors’ operation. This article proposes extra snubber cells to realize soft-switching operation of the converter. The extra snubber cell DBFBI (ESCDBFBI) topology has the advantages of high-precision current output and much lower total inductor volume. The basic operation and properties of the ESCDBFBI topology are explained. Finally, an 800-W prototype of the proposed inverter is built and the experimental results agree with the theoretical analysis.

Novel Multicarrier PWM Scheme for a Reconfigurable Single-Phase Inverter to Achieve Manifold Higher Effective Switching Frequency

Inverter operation at higher switching frequency brings several advantages. The article presents a novel multicarrier pulsewidth modulation (PWM) scheme along with a reconfigurable single-phase inverter topology. The combination facilitates multiple times higher effective switching frequency (ESF) at the inverter output. The novel reconfigurable topology incorporates additional pairs of series-connected switches in the conventional full-bridge inverter. The proposed PWM scheme uses multiple modified carrier waves to generate gate pulses for the various switches. Consequently, the switches operate in such a coordinated manner that ESF increases multiple times compared to the actual switching frequency of its switches. Thus, the scheme offers several advantages like reduced filter requirements, reduced overall size, weight, and cost. Moreover, the distortion in the output waveforms caused by the dead time is eliminated by a modified dead-time compensation technique, incorporated with the proposed PWM scheme. The proposed scheme is demonstrated here by configuring the proposed inverter topology as an eight-switch topology to achieve four times higher ESF. It is shown through analysis, simulations, and experimental results that in spite of including additional switches, a high-frequency operation can be achieved with a low cost. The proposed scheme may serve as an alternative to using wide bandgap devices, thereby saving cost and efforts.

Analytical study and simulation of a transformer-less photovoltaic grid-connected inverter with a delta-type tri-direction clamping cell for leakage current elimination

PurposeThis paper aims to propose a new transformer-less inverter structure to reduce the common-mode leakage current in grid-connected photovoltaic (PV) systems.Design/methodology/approachThe proposed circuit structure is the same as the conventional full-bridge inverter with three additional power switches in a triangular structure. These three power switches are between the bridge and the output filter, and they mitigate the common-mode leakage current flowing toward the PV panels’ capacitors. The common-mode leakage current mitigation is done through the three-direction clamping cell (TDCC) concept. By clamping the common-mode voltage to the middle voltage of the DC-link capacitors, the leakage current and the total harmonic distortion (THD) of the injected current to the grid is effectively reduced. Therefore, the efficiency is improved.FindingsThe switching modes and the control method are introduced. A comparison is carried out between the proposed structure and other solutions in the literature. The proposed topology and its respective control method are simulated by PSCAD/EMTDC software. The simulation results validate the advantages of the presented structure such as clamping the common-mode voltage and reducing leakage current and THD of injected current to the grid.Originality/valuePresenting a single phase-improved inverter structure with low-leakage current for grid-connected PV power systems represents a significant original contribution to this work. The proposed structure can inject a sinusoidal current with low THD to the AC grid, and the power factor is unity on the AC side. In the half positive cycle, one of the switches in the TDCC is turned off under zero current. Besides, one of the other switches in TDCC is turned on with zero voltage and, therefore, its turn-on switching losses are zero. The efficiency of the proposed topology is high because of the reduction of leakage current and power losses. Accordingly, the presented topology can be a good solution to the leakage current elimination.

Two-Stage Solar Photovoltaic-Based Stand-Alone Scheme Having Battery as Energy Storage Element for Rural Deployment

Solar photovoltaic (PV)-based stand-alone systems have evolved as a promising solution to the issue of electrification in areas where the grid is not available. The major challenges in designing such systems are as follows: 1) extraction of maximum power from the PV array; 2) protection of the battery from overcharge and overdischarge; 3) dc to ac conversion; and 4) provision for adequate voltage boosting. As multiple objectives are required to be satisfied, the existing schemes for stand-alone systems require a minimum of three converter stages, leading to considerable reduction in the reliability and efficiency of the system. In order to address this issue, a two-stage stand-alone scheme consisting of a novel transformer-coupled dual-input converter (TCDIC) followed by a conventional full-bridge inverter is proposed in this paper. The proposed TCDIC can realize maximum power point tracking and battery charge control while maintaining the proper voltage level at the load terminal. The small signal mathematical model of the TCDIC is derived. A suitable control strategy for the proposed TCDIC is devised. The operation of the scheme is verified by performing detailed simulation studies. A laboratory prototype of the scheme is developed. Detailed experimental validation of the scheme utilizing the laboratory prototype is carried out to confirm the viability of the scheme.

A Controlled-Type ZVS Technique Without Auxiliary Components for the Low Power DC/AC Inverter

This paper proposes a soft switching technique for dc/ac inverters, by using duty cycle and frequency modulation. Zero voltage switching (ZVS) is achieved through controlling the inductor current bidirectional in every switching cycle. This technique requires no additional resonant components and can be employed for various low power applications on conventional full-bridge and half-bridge inverter topologies. Three different current mode control schemes are derived from the basic theory of the proposed technique. They are referred to as boundary current mode (BCM), variable hysteresis current mode (VHCM), and constant hysteresis current mode (CHCM) in this paper and their advantages and disadvantages are compared. Simulation and experimental results demonstrate the feasibilities of the proposed soft-switching technique and its control schemes.

High torque polyphase segmented switched reluctance motor with novel excitation strategy

Switched reluctance motor (SRM) with simple and rugged construction is an efficient and inexpensive alternative to permanent magnet (PM) motors. However, SRM has lower torque output than a PM motor of the same frame size. An SRM design that improves torque output by using segmented rotor topology with five phases is designed and evaluated in this study. Further, a bipolar excitation strategy wherein two phases are concurrently excited is proposed. A conventional full bridge inverter is used to feed the motor. Prototype of this machine is fabricated for experimental validation of the proposed strategy. It is found that bipolar excitation strategy results in higher torque output.

A Novel Transformerless Inverter Topology Without Zero-Crossing Distortion

The elimination of the transformer in solar photovoltaic inverters has reduced the size, the weight and the losses in the system. On the other hand, the galvanic connection between the DC source and the grid generates leakage current through the earth parasitic capacitance. The leakage current depends on both the inverter topology and the control strategy. Among the existing inverters is the Highly Efficient and Reliable Inverter Concept (HERIC) topology that has low leakage current level and high efficiency. However, this topology suffers from low frequency harmonics and current zero crossings distortion s . To eliminate these harmonics and distortions, a new transformerless inverter is proposed. The design is a conventional full bridge inverter with an extra AC bypass. The bypass branch disconnects the inverter from the grid during the freewheeling period. Simulation results indicate that the zero crossings distortions are totally eliminated and that the low frequency harmonics are significantly reduced as a result of the appropriate applied control. Moreover, losses analysis of the proposed design yields an efficiency of up to 94.14% and shows that the topology meets relevant standards.

A Novel Control Technique for Soft-switching Sinusoidal Pulse Width Modulation Inverter

This article presents a new zero-current switching technique for a single-phase full-bridge sinusoidal pulse width modulation inverter. Two auxiliary switches and a resonant branch are attached to a conventional single-phase full-bridge inverter. The resonant branch can be controlled independently from the main power switches. This technique decreases turn-on and turn-off switching losses and does not require any snubber capacitor. The technique can be applied to DC/DC converters and DC/AC inverters with suitable switching algorithms. Both theoretical analysis and application of the proposed technique have been realized. It was seen that the proposed technique has 45% less switching losses and better performance than the hard-switching technique for the same load and switching frequency. The experimental results also approve the effectiveness of the zero-switching technique.