Harmonic Losses Research Articles

Speed control and quantum vibration reduction of Brushless DC Motor using FPGA based Dynamic Power Containment Technique

In modern industrial field Brushless DC Motor (BLDC) is important component of electromechanical energy conversion. The BLDC is used in many application like high power traction, high end pumps etc. In this BLDC motor have a drive to operate in a constant operation but some noise and losses are create, so the various control technique is used to reduce the noise although some harmonic loss is occur in existing system. In that reason a new Dynamic Power Containment Technique (DPCT) algorithm is developed to reduce the harmonic loss and increase the system efficiency. The inverter is used to drive the Brushless DC Motor (BLDC) in a constant speed operation. This proposed control system is replace to classical cascaded method in speed and current control of BLDC motor. The inverter input current is directly control with help of the proposed FPGA based DPCT control system. The proposed system performance is analysis through the MATLAB simulation software. This proposed DPCT model is given the solution of delay issue. Afterward, another immediate pay technique was proposed to foresee the adjustment in current inside the defer time. The existing comparison of two-step predictive strategy, the new method is also easier to develop and can be used for optimized control to choose the best switch state in each cycle.

Stray Load Loss Calculation for Induction Motor by Combination of General Airgap Field Modulation Theory and 2D FEA

The accurate calculation of stray load loss has an important contribution to increasing motor efficiency. The stray load loss can be regarded as the difference of the total iron losses and harmonic rotor cage losses between the no load and load conditions. A method combining the general airgap field modulation theory (GAFMT) and 2D finite element analysis (FEA) is proposed for calculating the stray load loss of the squirrel cage induction motor (SCIM). Firstly, the amplitudes and rotation speeds of the main space harmonics of the airgap magnetic flux density are calculated based on the GAFMT. And the relationships between these space harmonics and stray load loss are analyzed. Secondly, these space harmonics are synthesized by the equivalent current layers in the airgap and then are substituted into the 2D FEA models to calculate the losses. At last, the stray load loss calculated by the proposed method is compared with that obtained by practical motor tests.

Effects of free heave motion on wave resonance inside a narrow gap between two boxes under wave actions

Fluid resonance inside a narrow gap between two side-by-side boxes is investigated based on an open-source CFD package, OpenFOAM. An upstream box heaves freely under wave actions and a downstream box remains fixed. The focus of this work is to study the influence of the motion of the upstream box on the hydrodynamic behavior of the resonant fluid inside the gap. The hydrodynamic behavior considered in this study includes the wave height inside the gap, heave displacement and their harmonic components, and reflection, transmission and energy loss coefficients. For comparison, the configuration in which the two boxes are fixed is considered. It was found that the heave motion of the upstream box increases the fluid resonant frequency and significantly reduces the resonant wave height in the gap. The frequencies at which the maximum and minimum heave displacements of the upstream box are observed to obviously deviate from the fluid resonant frequency. For the wave height in the gap and heave displacement, the effects of the incident wave height on their harmonic components are different. The heave motion of the upstream box results in a larger reflection coefficient and smaller energy loss coefficient.

Advanced hybrid SVPWM techniques for two level VSI

ABSTRACT This paper brings an advanced class of hybrid SVPWM techniques for medium voltage drive applications with two-level inverter which employs multiple division of active vector time (MDAVT) switching sequences to reduce total harmonic distortion (THD) and switching loss. The proposed hybrid SVPWM techniques are categorised based on the principle of bus-clamping strategies. Multiple division active vector time (MDAVT) switching sequences are used in the proposed strategies. The newly developed MDAVT switching strategies produce PWM waveform for all odd and even pulse number and maintain the symmetry of the voltage waveform. This work compares different MDAVT switching sequences based on modulation index and location of the clamping position (zero vector changing angle) of a phase in a line cycle. The proposed techniques lead to the reduction in weighted total harmonic distortion of line voltage (Vwthd) as well as switching loss. The results point to the superior order of performance of the developed MDAVT sequences in the various ranges of operation of modulation index and power factor values. The superior harmonic performance and switching loss characteristics of the MDAVT PWM techniques over the conventional SVPWM is experimentally verifiedona415 V, 2 hp induction motor drive.

PI Regulator-Based Duty Cycle Control to Reduce Torque and Flux Ripples in DTC of Six-Phase Induction Motor

In this paper, a proper duty cycle control method is proposed to reduce torque and flux ripples and harmonic loss in direct torque control (DTC) of six-phase induction machine (6PIM). Three different methods are proposed to improve the performance of switching table DTC for 6PIM. First, by the suitable selection of two vectors in each sampling period, the harmonic amplitude is significantly decreased, but the torque and flux ripples are still large. Then, the abovementioned method is combined with duty cycle control technique and the torque and flux ripples and current harmonics are significantly reduced. In addition, the switching frequency is also reduced by selecting the suitable voltage vector in each sampling period. Finally, a simple control method is suggested to calculate the duty ratio of voltage vectors independently of machine parameters. Although neglecting the one-step delay makes performance of the final technique similar to the previous one, considering this delay in real conditions shows the following advantages for the final method: less torque and flux ripples, less current harmonics, simplicity, and constant switching frequency. Despite these improvements, all duty cycle-based DTC approaches (duty-DTC and PI-duty-DTC) increase the inverter switching losses. The simulation and experimental results presented in this paper verify the performance advantages of the proposed methods.

Study on the Harmonic Loss of Permanent Magnet Toroidal Space Motor for Hybrid Electric Vehicles

Based on magnetic gear transmission principle, permanent magnet toroidal space motor for hybrid electric vehicles with dual-rotor drive is proposed in this paper, harmonic loss caused by toroidal space relative motion of two rotors is conducted in hybrid drive mode. According to the structural principle of toroidal space motor, the speed of permanent magnet teeth of planet and worm inner rotor are decomposed to the revolution and rotation planes respectively. On the two planes, the frequency of alternating magnetic field at toroidal stator, planet and worm inner rotor are derived. At iron core and permanent magnetic teeth of stator and rotor, the magnetic field of revolution and rotation components are simulated. Combining with the speed relationship of toroidal space motor, the harmonic losses of revolution component and rotation component are analyzed in hybrid drive mode. The influence of speed matching of two rotors and toroidal stator material on harmonic loss are discussed. The results indicate that harmonic loss of permanent magnet toroidal space motor for hybrid electric vehicles can be reduced effectively by reducing relative speed of two rotors and adopting amorphous alloy for toroidal stator.

Comparative investigation of single-phase Distributed Grid-connected with and without D-STATCOM

Power quality becomes one of the significant contemplations in the power system. It has become significant particularly with the presentation of advanced devices. These high-level advanced devices are sensitive to the nature of the power supply. The power quality refers to the voltage, current, and frequency at the evaluated value. If any variation occurred in these quantities the standard rating is considered as the power quality problem. The power quality issues like loss of sine, voltage sag, voltage swell, short interruption, long interruption, flicker, and harmonics. To overcome these power quality issues, we like to utilize custom power devices on the distribution side. Among various custom power devices, Distribution Static Synchronous Compensator is liked to use for expanding the power quality, on account of their basic power supply at the circulation power system which can’t be interfered with development and less complexity. This paper presents the near research of single-phase with and without D-STATCOM by utilizing MATLAB Simulink programming.

A Novel Multi-Objective Based Reliability Assessment in Saudi Arabian Power System Arrangement

In a smart grid power system, reliability performance plays a crucial factor and requires additional focus. Moreover, the integration of Battery Energy Storage (BES) scheme, Solar Photovoltaic (SPV) and wind system in the smart grid system provide significant proficiency and reliability to the utilities. However, the grid coordination with the PV and other resources tends to cause major problems such as power interruption or else power outage. The outage of the power in the grid can cause power loss to the distribution system. Therefore, the novel reliability valuation of the smart grid system is developed for exaggeration of the SPV, wind and BES utilities based on the grid incorporation in Saudi Arabia. Furthermore, a novel Hobbled Shepherd Optimization (HSO) for boost converter control and Multi-Objective Based Golden Eagle (MOGE) algorithm for inverter control is proposed. The execution of this work has been done in MATLAB/Simulink. The simulation outcomes show that the projected method has attained the finest Total Harmonic Distortion (THD) and power loss. Also, the optimal reliability improvement has achieved by the projected methods while compared with the conventional methods in terms of Loss of Load Expected (LOLE), Loss of Load Probabilities (LOLP) and Expected Energy Not Supplied (EENS).

Fixed frequency Finite Control Set Model Predictive Control For Three-level APF

Active power filter can compensate harmonic and reactive power, Three level neutral point clamp (ANPC) has the characteristics of low output harmonic and low device loss. The control of three-level active power filter needs to consider multiple objectives. Finite control set model predictive control (FCS-MPC) is a new method which can add constraints and multi-objective control. According to the limit of the switch state, it can track the reference current, which has the characteristics of fast dynamic response and good compensation effect. This method not only keeps the neutral point voltage balance, but also solves the problem of unstable switching frequency.

Optimization and Analysis of a High Power Density and Fault Tolerant Starter–Generator for Aircraft Application

Permanent magnet synchronous machines provide many dramatic electromagnetic performances such as high efficiency and high power density, which make them more competitive in aircraft electrification, whereas, designing a permanent magnet starter–generator (PMSG), with given consideration to fault tolerance (FT), is a significant challenge and requires great effort. In this paper, a comprehensive FT PMSG design process is proposed which is applied to power systems of turboprops. Firstly, potential slot/pole combinations were selected based on winding factor, harmonic losses and manufacture issues. Then, pursuing high power density, a multiple objective optimization process was carried out to comprehensively rank performances. To meet a fault tolerance target, electrical, magnetic and thermal isolation topologies were investigated and compared, among which 18 slot/12 pole with dual three-phase was selected as the optimal one, with a power density of 7.9 kW/kg. Finally, a finite element analysis verified the performance in normal and post-fault scenarios. The candidate machine has merits concerning high power density and post-fault performance.

Hybrid PWM Methods for Harmonic Reduction in Neutral Point Clamped Three-Level Inverter Drive for Pump Applications

Two hybrid PWM methods are proposed in this paper for a pump drive based on three-level Neutral-Point Clamped (NPC) inverter. The envisaged PWM methods are aimed at reducing output voltage harmonic distortion. While the first PWM method incorporates suitable voltage injection to the carrier signals, the second PWM method incorporates voltage injection to both carrier and the modulating signals for controlling the NPC drive. Detailed harmonic analysis is presented using Double Fourier Integral Approach (DFIA) for both the hybrid PWM methods by separately identifying their basic unit cells, their boundaries that demarcates different regions of inverter drive. Complete analytical expressions for dc, fundamental, carrier and side-band harmonic components present in the output voltage of the NPC drive are presented for both the hybrid PWM methods. The proposed PWM methods are simulated using Matlab/Simulink and are experimentally validated using an induction motor driven pump load, following V/f control. Superiority of the hybrid PWM methods in comparison to the existing PWM methods are demonstrated with vTHD , weighted THD (vWTHD ), iTHD , harmonic loss factor etc., supporting the envisaged PWM methods.

AC–DC–AC Single-Phase Multilevel Converters Based on Three-Leg Modules Cascaded-Connected Through Transformers

This article investigates a family of single-phase ac–dc–ac multilevel converters that are capable of mitigating sags/swells and voltage harmonics in the grid supply, ensuring regulated load voltage (with fixed amplitude and frequency), and grid current with high power factor and low harmonic content. Thus, the converters are suitable to operate as a unified power quality compensator or uninterrupted power supply. The proposed topologies are composed of three-leg (3L) modules cascade-connected through transformers at the grid side. From the generalized model presented, topologies with two and three 3L modules are discussed. System equations, PWM strategies, and a control system are developed. Compared with the conventional one, the proposed topologies present better results in terms of harmonic distortions, semiconductor losses, and switching frequencies. Simulation and experimental results in different load conditions are provided to validate the feasibility of the system under grid disturbances and load transients.

Switched Capacitor-Based 13L Inverter Topology for High-Frequency AC Power Distribution System

The power converters are taking responsibility to produce high-quality output voltage and current waveforms from the various PV sources. Recently, PV applications focus on high-frequency ac power distribution (HF-AC-PD). In particular, dc/ac switched capacitor multilevel inverters (SCMLIs) significantly reduce the power conversion stages and components, which result in high conversion efficiency. This article proposes a new SCMLI topology with a reduced number of switches and a self-balanced floating capacitor (FC) voltage. The proposed topology is configured as a single dc source and three dc sources. The proposed topology generates thirteen level output voltage waveforms, and the output voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{o}$ </tex-math></inline-formula> ) is two times higher than the input voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{in}$ </tex-math></inline-formula> ). The discharging time is less than the recently suggested topologies. Furthermore, the voltage stress on switches is reduced to 50% concerning the load voltage. Thus, a remarkable reduction in the bulky size of the FC is achieved. The simulation results are discussed for different fundamental frequencies of 360 Hz, 400 Hz, and 1 kHz and considering various loads. The proposed converter prototype is designed in the laboratory for 2 kW, and the results are presented. The results show a good agreement in terms of total harmonic distortions, power loss, and efficiency.

Comparative Analysis of SVM Techniques for a Five-Phase VSI Based on SiC Devices

Multiphase systems provides benefits compared to three-phase systems, such as improved torque per ampere, high power density, better fault tolerance, lower current per phase (due to power-splitting among a higher number of phases), and lower torque ripple, among others. Depending on the application, the system must meet determined requirements, such as the presence of harmonic content, power losses, and common-mode voltage (CMV) generation. This paper presents a comparative analysis of space vector modulation (SVM) techniques applied to a five-phase voltage source inverter with SiC switches to provide an overview of their performance. The performance of five-phase 2L SVPWM (space vector pulse width modulation), 2L+2M SVPWM, 4L SVPWM techniques, and their discontinuous versions, are analyzed by focusing on harmonic content, power losses, and CMV generation using SiC semiconductor devices. Matlab/Simulink and PLECS simulations are performed to achieve the above mentioned goal. The use of different techniques allows (1) reducing the harmonic distortion when 2L+2M SVPWM and 4L SVPWM are applied, and (2) the switching sequence of the modulation techniques can influence the switching losses. Therefore, the use of SiC switches reduces the switching losses. (3) However, CMV dv/dt increases. Therefore, it is possible to minimize the effects of the CMV dv/dt and amplitude by choosing the adequate technique.

Influence of field-dependent critical current on harmonic AC loss analysis in HTS coils for superconducting transformers supplying non-linear loads

There are two main obstacles in front of the development of high temperature superconducting (HTS) technology for electric power network applications; tape price and cooling cost. In order to reduce cooling cost, it is vital to evaluate AC transport current loss of the tapes precisely and then reduce it by some design innovative approaches. In addition, AC transport current loss in HTS material is a critical design variable for large-scale power network applications such as HTS transformers, superconducting fault current limiters, and power cables, since they are continuously carrying the network/load current during their operating life. In existing power networks, harmonic production sources are commonly used and thus, currents are distorted. Therefore, the effect of nonsinusoidal current on the critical apparatus in the network such as transformer must be studied. In this paper, AC transport current loss of a single-turn 2G YBCO HTS coil was modeled and numerically calculated under nonsinusoidal transport current using finite element method. Furthermore, influence of dependency of critical current density to magnetic field on the AC transport current loss of HTS coil when carries distorted currents was considered. It was observed that nonsinusoidal current causes excessive losses in HTS coil. On the other hand, a case study on an HTS transformer supplying non-linear load was considered to study the loss increment as well as heat load change. It was observed that current harmonics increases the AC loss, and heat load of transformer and decreases the efficiency, consequently.

Harmonic loss analysis of converter transformer in LCL-HVDC system

At present, China’s energy distribution and economic development are extremely unbalanced. In order to make rational use of resources, China has promoted the “west to East power transmission” and “north to South Power Transmission” pattern. HVDC transmission has obvious advantages in this long-distance transmission, but there are some shortcomings in the traditional LCC-HVDC system. Therefore, a new system LCL-HVDC is proposed. Firstly, some advantages of the system are introduced; secondly, LCC-HVDC and LCL-HVDC models are built in Simulink, in which the current distortion rate of valve side winding of converter transformer is measured; finally, compared with LCC-HVDC, the loss of LCL-HVDC converter transformer is studied by using method 2 recommended by IEEE standard, and the kn value of the new system is calculated.

Influence of Electric Loading and Rotor Speed on the Performance of Permanent Magnet Machines

The impact of electric loading such as current, copper loss and current density as well as the effect of rotor speed on the performance of double stator (DS) permanent magnet (PM) machines are analyzed and presented in this work. MAXWELL-2D software package is used in predicting the results. The investigated machine variables include: phase flux-linkage, induced phase voltage, average torque, torque ripple, total harmonic distortion, losses and efficiency. The analysis shows that most of the machines’ output performances are principally dependent on both the operating speed and loading conditions; though, the average torque and phase flux-linkage is fairly insensitive to change in speed.

Microbubbles Cloaked with Hydrogels as Activatable Ultrasound Contrast Agents.

Microbubbles (MBs) are optimal ultrasound contrast agents because their unique acoustic response allows for exquisite sensitivity in vivo. This unique response is derived from MBs' elasticity that allows them to oscillate differently from surrounding tissues. While the main use of MBs in the clinic is for cardiac and perfusion imaging, imparting MBs with bioresponsive properties would expand their use to detect pathophysiologic changes. This can be achieved by damping MBs' oscillations to silence their signal and rescuing it when they encounter the biomarker of interest to improve detection and specificity of diseases such as deep vein thrombosis (DVT). Here, we demonstrate that conjugating perfluorobutane-filled MBs with hyaluronic acid (HA) and cross-linking HA with biodegradable linkers eliminates harmonic signal because of increased MB stiffness and decreased oscillation. In this proof-of-concept study, we used a reversible pH-sensitive cross-linker to establish and validate this targeted and activatable pH-sensitive MB (pH-MB) platform. Conjugation of HA to MBs and targeting of pH-MBs to CD44-positive cells were validated. Harmonic signal loss due to stiffening of pH-MBs' shell was confirmed using a clinical ultrasound scanner equipped with Cadence contrast pulse sequencing. pH-MBs imaged before and after acidification increased harmonic signal fivefold. Because the cleavage of the cross-linker we used is reversible, harmonic signal was silenced again when the acidic suspension was neutralized, confirming that harmonic signal is dependent on the cross-linked HA. The rate of rise and the magnitude of harmonic signal increase could be manipulated by varying the phospholipid composition and the number of HA cross-linkers, indicating that the platform can be tuned to the desired response needed. In this study, we established the feasibility of using targeted and activatable MBs and plan to apply this platform to aid in the diagnosis and management of patients with DVT and potentially other conditions.

A Novel Rotor Structure of Claw-pole Motor Designed by Magnetomotive Force-based Simulation Method

In this paper, we propose a novel rotor structure of claw-pole motor (CPM) to reduce harmonic iron loss. In order to realize this low iron loss structure, a magnetomotive force-based a simulation method is presented to clarify the cause of harmonic iron loss. As the proposed method is based on mathematical theory, the rotor structure can be evaluated with a low computational cost. To validate its effectiveness, conventional and the proposed model are analyzed using the finite element method. The results indicate that the harmonic loss of the developed rotor is lower than that of the conventional rotor.

Improved Harmonic Iron Loss and Stator Current Vector Determination for Maximum Efficiency Control of PMSM in EV Applications

The accurate control of interior permanent magnet synchronous machine (IPMSM) and drive in electric vehicle applications is vital for achieving superior performance over a wide range of speeds and loads. Many control methods such as loss minimization and maximum efficiency (ME) have been developed to improve the efficiency of the motor–drive, by mainly considering the controllable fundamental losses. This article includes the effect of stator harmonic iron losses caused primarily by inverter sideband time harmonics that contribute to a significant amount of controllable electrical losses in IPMSMs. The sideband harmonic iron losses have been analytically modeled using a novel dq –axis model incorporating harmonic iron loss resistance. Subsequently, the harmonic iron losses have been included in an offline procedure used to determine optimal current advance angle for increased motor efficiency. The improved IPMSM losses and subsequently, the analytical efficiency models have been derived by considering varying motor parameters due to saturation and cross–saturation effects. The accuracy of the developed model and the improved ME control using the optimal current angle have been validated using numerical simulations and experimental investigations on a laboratory IPMSM.