Dc-link Utilization Research Articles

DC-Link Utilization Enhanced Implicit Model Predictive Control for Dual Three-Phase PMSMs

DC-Link Utilization Enhanced Implicit Model Predictive Control for Dual Three-Phase PMSMs

Full-Speed Region Predictive Current Control Method of Symmetrical Series-Winding PMSM With Higher DC-Link Utilization

Full-Speed Region Predictive Current Control Method of Symmetrical Series-Winding PMSM With Higher DC-Link Utilization

Effective DC Link Utilization of Multilevel Dual Inverter With Single Source in the Maximal Distention Mode

Effective DC Link Utilization of Multilevel Dual Inverter With Single Source in the Maximal Distention Mode

Combining Common DC-Link Utilization and Zero-Sequence Injection for Power Balancing in Hybrid Cascaded H-Bridge PV Inverters

Combining Common DC-Link Utilization and Zero-Sequence Injection for Power Balancing in Hybrid Cascaded H-Bridge PV Inverters

SSD-Based PSPWM Inverter Control for Grid-Integrated PV/Wind System with EPO-Based MPPT Using High Gain Converter

In this proposed work, Social Ski Driver (SSD)-based Phase Shift Pulse Width Modulation (PSPWM) controller for grid-connected solar photovoltaic (PV) and wind turbine with Emperor Penguin Optimization (EPO)-based Maximum Power Point Tracking (MPPT) is proposed. The PV panel and wind turbine generate the power, which is tracked by an EPO-based MPPT controller for maximum power. SSD-based PSPWM controller is used in the Voltage Source Inverter (VSI) for effective DC link utilization with less harmonic content. Multiple Input Single Output (MISO) super lift positive output LUO converter is a high-gain converter used for DC-DC conversion, which boosts the voltage of PV and wind. According to the switching signal, the converter provides improved voltage to the DC link. The wind system uses the Doubly Fed Induction Generator (DFIG) to convert mechanical energy into electrical energy. The gate pulse of VSI is tuned with SSD-based PSPWMs, thus will control the DC link voltage and provides a better voltage and current waveform with less harmonic content. This proposed system is implemented in MATLAB/Simulink software. The voltage and current values of an inverter, PV panel, wind turbine, DC link and grid are analyzed, and harmonic reduction for different frequencies are compared. The proposed system provides a better voltage and current waveform with less harmonic content.

An open circuit fault-tolerant seven-level inverter with symmetric sources and reduced switch count

In this study, a new structure of symmetrical multilevel inverter is proposed. The proposed structure offers fewer controlled switches, power diodes, DC sources voltage stress across switches and losses compared with classical and a few recently proposed topologies in the literature. This paper presents a fault-tolerant (FT) seven-level inverter to provide uninterrupted supply to the connected load under open circuit fault in any single switch of the presented configuration. This configuration uses only six unidirectional and one bidirectional switch for any switch fault-tolerant operation. The phase opposition disposition sinusoidal pulse width modulation (POD-SPWM) and phase disposition sinusoidal pulse-width modulation (PD-SPWM) scheme are used for proper DC link utilisation in seven-level output voltage. The proposed symmetrical 7-level topology requires fewer power components and offers reduced voltage total harmonic distortion (THD) compared to other multi-level inverter (MLI) topologies. This MLI is investigated in MATLAB and validated using hardware in the loop platform of OPAL-RT. The obtained results are presented to demonstrate the successful FT operation under any single switch open circuit fault.

Comparison of 2L + 2M and 6L SVPWM for Five-Phase Inverter to Reduce Common Mode Voltage

Multiphase drives have received a lot of interest because of their several features over traditional three-phase systems for high-power applications. Pulse-width modulation (PWM) approaches are necessary to regulate the supply for multiphase ac drives. As a result, it is vital to continually improve the modulation and control approaches used to upgrade output power converters’ quality. This paper offers a comparative analysis of the 2L + 2M and 6L space vector pulse-width modulation (SVPWM) techniques applied to a five-phase two-level voltage source inverter (VSI) fed an inductive (R-L) load. The comparative evaluation is based on measuring the inverter switching losses, the total harmonic distortion (THD) values, and the common mode voltage (CMV) under different operation scenarios. A system model is carried out by MATLAB/Simulink. An experimental prototype is constructed in the lab to validate the theoretical analysis. Simulation results for the system based on the two SVPWM techniques are obtained at different modulation indices and different output frequencies and are confirmed by the experimental results. It has been found that the peak-to-peak CMV of the 6L method is 80% lower than that of the 2L + 2M method. Moreover, 6L SVPWM offers better DC-link utilization compared to 2L + 2M SVPWM.

Linear Modulation Region Expansion Strategy Based on Voltage Vector Angle Regulation for PMSM Drives With Small DC-Link Capacitor

Modulation fluctuations will decrease the linear operation range and cause the reduction of DC-link utilization for reduced DC-link capacitance motor drives. In this paper, a novel strategy for expanding the linear modulation region based on voltage vector angle regulation is proposed. The phase relationship between the voltage reference and the DC-link voltage fluctuation is carried out creatively to clarify the reduction of linear modulation margin. Based on the impedance matching method, the linear modulation region can be expanded by reducing the phase differences with the regulation of voltage vector angle. According to parameter and performance analysis of the proposed method, the DC-link utilization can be improved by 13.2%. Experimental results validate that the effectiveness of the proposed method.

Open-Phase Fault-Tolerant DTC Technique for Three-Level NPC VSI-Fed Five-Phase Induction Motor Drives

The demand for motor drives based on multiphase machines (MMs) is increasing due to their inherent fault-tolerant capabilities. To achieve satisfactory post-fault operation, a proper fault-tolerant controller is needed. Some direct-torque-control (DTC) techniques have been reported for five-phase induction motor (FPIM) drives under an open-phase fault (OPF). DTC offers simplicity, fast response, and less parameter sensitivity. However, the existing fault-tolerant DTC methods were designed for two-level voltage-source inverters (VSIs). A three-level neutral-point-clamped (NPC) VSI allows greater flexibility in the switching states, lower current and torque ripple, and reduced common-mode voltage (CMV). However, the increased number of switching states requires the design of new DTC methods, able to tolerate OPFs while providing satisfactory performance in various aspects. In this article, two fault-tolerant DTC techniques are developed for three-level NPC VSI-fed FPIM drives under an OPF. The possible switching states are synthesized with suitable virtual vectors (VVs), addressing the dc-link voltage balance, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\text {d}v/\text {d}t}$ </tex-math></inline-formula> , CMV, and dc-link utilization. The two methods are compared under an OPF in these terms, as well as regarding the average switching frequency. Comparative experimental results are provided to assess the viability of the developed DTC schemes at steady-state and dynamic conditions.

Energy efficiency evaluation of a three-phase extendable-level inverter

This paper details the energy efficiency evaluation of an Extendable-Level Inverter (ELI). ELI achieves very high voltage levels, excellent DC-link utilization, and very good power quality with a minimized component count. An experimental setup of a three-phase ELI is implemented to investigate the power losses and to calculate efficiency. The ELI obtained a high efficiency of 99.09% with reduced switching and conduction power losses of 0.1% and 0.81% respectively. Comparative analysis of the theoretical calculation, simulation results and hardware results validated the consistency of a very high efficiency of over 99.09% for a broad range of operating frequencies. The power quality metrics conformed to the limits prescribed in the IEEE 519 standard.

Sustainable power conversion topology based STATCOM for reactive power compensation

The stability of AC voltage is one of the vital drawbacks affecting the power transfer capability. FACTS devices open a new control technology for mitigating this problem to a great extent. But the size, DC link utilization, and stability of the controlling device is still a major concern. The main thrust is to improve the quality of reactive current injected for voltage enhancement in the power system. This paper proposes a new inverter based STATCOM with fewer components and high DC link utilization. This will reduce voltage stresses across the devices. The required DC link voltage is being curtailed by 1.57 times. When compared to multilevel level inverters, less number of switches and one high-frequency switching is required per phase. The simultaneous switching of devices in the same leg eliminates the shoot-through problem. The proposed method improves the quality of injected current for reactive power compensation and load voltage has attained THD (total harmonic distortion) 2%. MATLAB- Simulink platform is used for simulation and verified with experimental results.

Hybrid Multivector FCS–MPC for Six-Phase Electric Drives

Standard finite control set model predictive controllers (FCS–MPC) suffer from a deteriorated current quality when applied to multiphase drives. This problem has been recently mitigated with the concept of virtual voltage vectors. Its application ensures reduced current harmonics by limiting the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x–y</i> voltage injection. An intensive research effort has been done seeking for the best vector combination to provide an optimized performance in FCS–MPC. On one hand, multivector strategies including a null vector refine the effective voltage production with enhanced current quality but the dc-link utilization decreases. On the other hand, the exclusive use of large virtual vectors (LVVs) ensures a higher dc-link utilization at the price of a poorer current quality at low-voltage operation. This article first proposes an extended version of multivector strategies using a zero vector by including a quartet of voltage vectors. The usage of five switching states into the predictive approach (MV5–MPC) improves the current quality but still lacks a suitable utilization of the dc-link voltage. To overcome this limitation, the proposed MV5–MPC is combined with LVV–MPC to provide a hybrid solution that simultaneously achieves a higher current quality and a satisfactory dc-link utilization. Experimental results confirm the effectiveness of the proposal.

Predictive Current Control of Six-Phase IM-Based Nonisolated Integrated On-Board Battery Charger Under Different Winding Configurations

Integrated on-board battery charging (IOBC) constitutes one of the future trends and the potential state-of-the-art technologies proposed for high-power chargers of electric vehicles. Model predictive control has recently been favored in different applications due to its simplicity in defining new control objectives and the straightforward handling of nonlinear constraints. In this article, the predictive current control (PCC) is applied to a six-phase induction-machine-based IOBC with three different winding configurations. From the grid perspective, this article introduces the required winding connections that maximize the charging grid current. Under PCC, different stator phases are controlled to draw balanced three-phase grid currents through controlling the machine nontorque-producing <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>xy</i></b> current components while ensuring zero average/ripple torque production. This article also discusses the effect of winding configuration on the mapping of the 64 available voltage vectors to the <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>αβ</i></b> , <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <i>xy</i></b> , and <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0⁺ 0⁻</b> subspaces. The optimal subset voltage vectors of each configuration that achieve the highest possible dc-link utilization, zero torque production, minimum total harmonic distortion (THD), and unity power factor are then introduced. The feasibility to employ the concept of virtual voltage vectors to improve the current quality is also investigated. The three six-phase configurations are obtained from an externally reconfigured 1 kW 12-phase induction motor, which has been used to experimentally validate the theoretical findings.

Improved DC bus utilization of DVR based on repetitive controller with THIPWM technique

A DVR is being used to minimize the power quality problem. The SPWM method has been popularly used in DVR but use of the DC bus is restricted in SPWM, which is critical due to economical as well as power packaging density improvements. The proposed THIPWM scheme has been deduced from SPWM by adding one-sixth of the third harmonic signal in the fundamental signal. Repetitive Controller (RC) with Third Harmonic Injection (THI) technique is applied to achieve better dc-link utilization for medium-low voltage distribution. As an outcome, it's indeed evident that 15% reflects an increment in dc bus utilization as well as the potential to create high voltage AC. The control system comprises a feed-forward as well as feedback run to enhance the transient response & confirm the steady zero error. THD results improve when the THIPWM methodology is being used. PSCAD software is being used for the computation, which generated accurate findings for the THIPWM and Repetitive Control systems approach.

A Finite Control Set Model Predictive Control for Five-Phase PMSMs With Improved DC-Link Utilization

Finite control set model predictive control (FCS-MPC) based on virtual voltage vectors (V3s) is widely studied and applied in five-phase permanent magnet synchronous motor (PMSM) drives. The synthesized V3s can inherently eliminate <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xy</i> -axes voltages and reduce the number of candidate vectors, which can significantly reduce the computation burden. However, the dc-link utilization is reduced due to the usage of V3s. To address this issue, an FCS-MPC method with improved dc-link utilization is proposed in this article. First, only large vectors are selected to predict the system evolution. The large vector that minimizes cost function is selected, and rescaled using the duty ratio estimation. Then, in order to control the third harmonic currents, three adjacent large vectors are applied to replace the selected vector, and the duty ratios are reassigned. Additionally, zero vectors are replaced with two opposite large vectors to reduce common-mode voltage (CMV). Finally, the proposed FCS-MPC is compared with conventional methods in experiments. Experimental results have verified that the proposed method can improve the dc-link utilization, and keep the superiorities of low CMV and low computation burden.

Grid integration of multiple wind turbines using a multi-port converter—A novel simultaneous space vector modulation

In this paper, an innovative approach of integrating multiple doubly-fed induction generator (DFIG)-based wind turbines using a single multi-port converter unit, named as a unified expandable power converter (UEPC) is presented. A novel partial simultaneous space vector modulation (PSSVM) scheme, adopted to the unified structure, is proposed to enhance the operational efficiency and DC-link utilization. The unified configuration can integrate two or more DFIGs through a multi-port converter in a cost-effective and efficient way. The unified structure enjoys compactness, plug & play capability, fewer switches, and a lower installation cost. Comparing with the conventional sequential space vector modulation (SSVM), which only uses the individual active vectors, the proposed PSSVM can utilize common active vectors between different ports, which is the main salient feature of this method. The performance of PSSVM is also validated via an OPAL-RT real-time simulator. The real-time outcomes prove that the proposed PSSVM can improve the DC-link voltage utilization and switching loss compared with the SSVM. The effectiveness of the proposed PSSVM based unified configuration in both normal and faulty conditions are evaluated and compared with the conventional structure using MATLAB/Simulink. The simulation results endorse the finding that regardless of the shared switches in the unified expandable power converter, the independent control and maximum power extraction from the wind are guaranteed using the proposed PSSVM.

FPGA-Based Reduced Switch Novel Infinite-Level Inverter

The evolution of multi-level inverters (MLIs) has led to an increase in their efficiency and reliability. This paper demonstrates an FPGA-based reduced switch novel Infinite-Level Inverter. Conventional two-level Voltage Fed Inverters (VFI) suffer from reduced efficiency, greater voltage distortion and higher switching losses. Multi-level inverters (MLI) outweigh the conventional inverter in terms of improved voltage profile, reduced switching losses, increased efficiency and lower component count. This paper demonstrates an FPGA-based Reduced Switch Novel Infinite-Level Inverter that achieves infinite voltage output levels; with a reduced count of passive and active elements. The proposed inverter has a high DC-link utilization factor of 1.23, reduced blocking voltage and inverter switching losses, employing a single DC source and least number of components. It outputs a sinusoidal voltage with a minimum voltage distortion of 2.1%, which lies within the approved limits of IEEE 519-2014 standard. Comparative studies of the proposed inverter are conducted with different multi-level inverter configurations. FPGA-based control of the proposed inverter reduces execution time and enhances the control performance of the inverter. Evidently, the low cost function of the proposed inverter indicates the economic feasibility of the developed inverter for low-power, low-cost applications.

Hybrid Multicarrier Random Space Vector PWM for the Mitigation of Acoustic Noise

The pulse width modulation (PWM) inverter is an obvious choice for any industrial and power sector application. Particularly, industrial drives benefit from the higher DC-link utilization, acoustic noise, and vibration industrial standards. Many PWM techniques have been proposed to meet the drives’ demand for higher DC-link utilization and lower harmonics suppression and noise reductions. Still, random PWM (RPWM) is the best candidate for reducing the acoustic noises. Few RPWM (RPWM) methods have been developed and investigated for the AC drive’s PWM inverter. However, due to the lower randomness of the multiple frequency harmonics spectrum, reducing the drive noise is still challenging. These PWMs dealt with the spreading harmonics, thereby decreasing the harmonic effects on the system. However, these techniques are unsuccessful at maintaining the higher DC-link utilizations. Existing RPWM methods have less randomness and need complex digital circuitry. Therefore, this paper mainly deals with a combined RPWM principle in space vector PWM (SVPWM) to generate random PWM generation using an asymmetric frequency multicarrier called multicarrier random space vector PWM (MCRSVPWM). he SVPWM switching vectors with different frequency carrier are chosen with the aid of a random bi-nary bit generator. The proposed MCRSVPWM generates the pulses with a randomized triangular carrier (1 to 4 kHz), while the conventional RPWM method contains a random pulse position with a fixed frequency triangular carrier. The proposed PWM is capable of eradicating the high-frequency unpleasant acoustic noise more effectually than conventional RPWM with a shorter random frequency range. The simulation study is performed through MATLAB/Simulink for a 2 kW asynchronous induction motor drive. Experimental validation of the proposed MCRSVPWM is tested with a 2 kW six-switch (Power MOSFET–SCH2080KE) inverter power module-fed induction motor drive.

Simple Carrier-Based PWM for Prolonged High DC-Link Utilization for Symmetrical and Asymmetrical $n$-Phase AC Drives

Square voltage waveforms enable high dc-link utilization (DLU) in multiphase ac drives. Circulating-current filters were devised to attenuate the harmonics in no-torque low-impedance subspaces. Nonetheless, the square-wave harmonics that generate torque ripple are not reduced. Recently, it was proposed to combine circulating-current filters with a carrier-based pulsewidth modulation (PWM) method, which injects harmonics in no-torque subspaces (attenuated by the filter) of five-phase motors to achieve high DLU, without harmonics associated with torque ripple. The filter allows prolonged high-DLU operation without overheating. Compared with other PWM techniques capable of high-DLU operation (overmodulation), the one proposed for said filters is especially convenient because of its simplicity. However, it is unclear if this PWM method can be extended to machines of any phase number n and winding arrangement (symmetrical or asymmetrical); and if so, the resulting performance is also unknown. This article extends this simple carrier-based PWM strategy to n-phase drives, and evaluates its behavior in terms of DLU, distortion, and computational burden. Symmetrical and asymmetrical winding arrangements are considered. The improvement in DLU, compared with conventional PWM with zero-sequence injection, is considerable. Current distortion is negligible with a suitable filter. The simplicity over other high-DLU PWM techniques is remarkable. Experimental results are provided.

Novel SVPWM technique for three-level T-type Z-source inverters

In this paper, a new SVPWM switching technique, named ZSVM_1TI, has been proposed for a three-level (3L) T-type Z-source inverter (ZSI). ZSVM_1TI is based on three main modifications of the existing PWM techniques for 3L inverters. First, the existing SVPWM of a 3L ZSI has been modified to double the frequency of the null interval. After that, an improved version of the maximum boost control (MBC) has been proposed based on modified SVPWM to eliminate the problem of the sixth frequency ripple components of inductor current with the existing MBC technique of ZSIs. Finally, a new switching pattern of a reduced common-mode voltage (CMV) PWM technique has been proposed to increase the switching frequency of the impedance network so that the size of the passive elements can be reduced. The proposed ZSVM_1TI has been compared with the existing PWM technique in terms of the size of the impedance network, the dc-link utilization, and the inductor current ripple profile. The above-mentioned findings have been successfully validated using theoretical analysis, simulations, and experimental results.