Passive Shunt Research Articles

Mitigation of electric field near overhead transmission lines using electromechanical compensation based on genetic algorithm

The electrical field is a function of both the voltage and the configuration of the overhead transmission line (OTL); thus, mitigation of the electrical field could be achieved by either electrical compensation or mechanical rearrangement of the line configuration. In the mechanical rearrangement method, the conductor positions are optimized under certain constraints so that the electrical field has the minimum possible value. In the proposed research, OTL mechanical rearrangement is improved using electrical compensation based on a genetic algorithm (GA). The electrical compensation is implemented by inserting a combination of passive series and shunt elements in each phase, creating an electric voltage imbalance. GA is an evolutionary optimization algorithm used to minimize the electric field near residences as a fitness function. The positions of conductors and passive-reactive elements are represented as genes. In addition, this paper includes a case study on a 500-kV high-voltage overhead transmission line. The results show that when passive-reactive compensation is combined with mechanical compensation, the lowest electric field can be obtained. Electrical compensation improves the mechanical rearrangement method by approximately 18.6% (the total reduction with mechanical compensation of only about 34% is increased to more than 52% with electromechanical compensation).

Reduction of vortex-induced vibrations of a cantilevered hydrofoil with passive piezoelectric shunt

This work first investigates the ability of a low order fluid-structure model to fit the vortex-induced vibrations (VIV) observed on a truncated hydrofoil in a hydrodynamic tunnel. A particular VIV area is scrutinized, for which a hydrodynamic excitation mechanism due to a Karman-type vortex wake organization successively locks the first torsional and second bending mode of the cantilevered hydrofoil. Coupling two structure oscillators with a Van der Pol wake oscillator satisfactorily reproduces the amplitude response and the lock-in frequency. In order to build a low order model allowing to optimize control strategy, a fourth degree of freedom corresponding to the electric circuit of a resonant piezoelectric shunt has been added. Composed of an inductance and a resistance connected to a piezoelectric patch, the passive shunt was tuned to minimize the vibration amplitude in the frequency lock-in range. Model predictions are finally compared with experimental results.

Elective open repair with the debranch, perfuse, reconstruct technique to treat suprarenal or type IV thoracoabdominal aortic aneurysms

BackgroundOpen surgical repair of suprarenal abdominal aortic aneurysm (SRAAA) and type IV thoracoabdominal aortic aneurysm (TAAA) remains a surgical challenge because of the inducted intraoperative visceral and renal ischemia. We report a novel three-step technique named debranch, perfuse, reconstruct (DPR), using debranching and passive arterial shunt to decrease these ischemic complications. The main aim of this study was to evaluate the 30-day and 1-year mortality rates associated with these DPR technique. The secondary aim was to evaluate the impact on renal function and the primary patency of the repaired arteries. MethodsThis retrospective study included all consecutive patients who underwent elective surgery for SRAAA or type IV TAAA using the DPR technique between January 2011 and June 2022. In debranching, using partial side clamping, a multibranch graft was implanted side-to-end into the descending thoracic aorta. The left renal artery was anastomosed end-to-end to the graft. As needed, the superior mesenteric artery (SMA), the celiac trunk, and the right renal artery could also be anastomosed to the graft. In the perfusion step, cannulas were connected to the last branch of the multibranch graft to perfuse other arteries during aortic cross-clamping. For repair, a tube or bifurcated graft was used for the aortic repair. The branch used as a passive temporary arterial shunt was ligated at the end of the intervention. Clinical, radiological, and biological preoperative and postoperative factors were reviewed using a standardized database. Procedural complications and reinterventions were analyzed, as well as artery patency. ResultsThere were 40 patients who underwent DPR technique. The mean patient age was 67 ± 13 years and two were women. Twenty-three patients presented with a SRAAA and 17 with a type IV TAAA. The 30-day and 1-year mortality rates were 2.5% (one patient). Two respiratory complications (5%) and three mesenteric ischemic complications (7%) have been recorded. No patient developed signs of cardiac or spinal cord dysfunction. We did not observe a significant change in postoperative renal function. The celiac trunk, superior mesenteric artery, left renal artery, and right renal artery bypass patency rates at 1 year were 95%, 100%, 90%, and 100%, respectively. ConclusionsThe SRAAA and type IV TAAA repair with DPR technique provides short visceral and renal ischemia times with a low mortality rate. This technique could be an option to consider for visceral and renal protection during open surgical repair.

On the Feasibility of Self-Powered Linear Feedback Control

A control system is called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">self-powered</i> if the only energy it requires for operation is that which it absorbs from the plant. For a linear feedback law to be feasible for a self-powered control system, its feedback signal must be colocated with the control inputs, and its input-output mapping must satisfy an associated passivity constraint. The imposition of such a feedback law can be viewed equivalently as the imposition of a linear passive shunt admittance at the actuation ports of the plant. In this paper we consider the use of actively-controlled electronics to impose a self-powered linear feedback law. To be feasible, it is insufficient that the imposed admittance be passive, because parasitic losses must additionally be overcome. We derive sufficient feasibility conditions which explicitly account for these losses. In the finite-dimensional, time-invariant case, the feasibility condition distills to a more conservative version of the Positive Real Lemma, which is parametrized by various loss parameters. Three examples are given, in which this condition is used to determine the least-efficient loss parameters necessary to realize a desired feedback law.

A Physical Framework for Testing and Evaluating of a Mechatronic Shunting System

Shunt is a flexible tube called a catheter implanted inside the brain where cerebrospinal fluid (CSF) is produced. Existing treatments rely on passive implantable shunts with differential pressure valves. The authors defined, designed, and programmed an intelligent wireless hydrocephalus shunting system. The shunting system was designed, simulated, and tested to carry out many tasks such as regulating the mechatronic valve, collecting Injection Control Pressure (ICP) readings, analyzing these readings, responding to all emergency cases, and diagnosing the whole shunting system. Nowadays, many challenges face clinical trials for new medical devices. Clinical trials are complex and require following several rules and regulations to ensure compliance with different standards. Due to the difficulty of using medical trials, an urgent need for a physical framework for implementing a virtual model of intracranial pressure and cerebrospinal fluid dynamics in hydrocephalus mechatronic shunt testing. Such a physical framework will play a vital role in assessing the functioning of the whole mechatronic shunting system. A framework of a mechatronic shunting system (implanted and external) is illustrated and integrated with embedded management and diagnosis software. Such a framework will help assess, test, and evaluate the main functions of the proposed shunting system.

Interval Type - 2 Fuzzy Logic Controller Based Shunt Active Power Filter for Power Quality Enhencement

Frequent wide spread of power electronics equipment to consumers have led to power quality problem in power system network, as a result to their nonlinear in nature. Due to this problem, current and voltage wave forms are no longer sinusoidal, which resulted in harmonics on them. Various methods have been deployed in order to mitigate the harmonic issues, like passive power filters and shunt active power filters. Presently, passive power filters are limited in used, because of its demerits as it produced parallel resonances, heavy in size and mitigate few harmonics. With the advancement in technology, shunt active power filters have become superior to passive power filters due to its limitations. Shunt active power filters was tested for suppressing harmonics produced by nonlinear loads. This article, used synchronous reference frame (SRF) in generating harmonic produced by nonlinear loads. However, T2FLC is utilized in controlling the DC bus voltage of the filter constant. Hysteresis current controller was introduced for firing the gating signal of the IGBT inverter circuit. MATLAB software was deployed in the simulation work. Results obtained have satisfied the tolerable 2014 revised harmonics limit.

Enhanced Semi-active piezoelectric vibration control method with shunt circuit by energy dissipations switching

Piezoelectric vibration control holds the advantages of lightweight and anti-electromagnetic interference, and has broad application prospects in fields such as aerospace and mechanical engineering. A semi-active control method based on a piezoelectric smart cantilever beam with a passive shunt circuit is proposed for vibration control. The contribution is that the proposed semi-active control method is used to achieve energy dissipations switching by changing the piezoelectric electrical boundary conditions. The open-circuit state of piezoelectric materials corresponds to higher stiffness and dissipation of elastic potential energy, while the short-circuit state is accompanied by lower stiffness and dissipation of electrical energy. Firstly, the stiffness difference of different electrical boundary conditions of the piezoelectric materials is derived and its effect on the vibration characteristics is analyzed. Then, the proposed passive shunt circuit for the vibration control principle is analyzed, and the modeling of the piezoelectric smart cantilever beam with the passive shunt circuit is developed. Finally, a prototype is manufactured and the measurement system is constructed. The correctness and the feasibility of the semi-active vibration control method are verified by experiments, and the logarithmic damping coefficient is 0.8919. The superiority of the proposed shunt circuit is demonstrated experimentally with the comparison groups including depolarized comparison group and the common shunt circuits.

Design of a piezoelectrically actuated hydrocephalus shunt valve

Hydrocephalus is currently managed by using traditional mechanical passive shunts. Due to their nature, these shunts have fundamental shortcomings including an increase in patient shunt dependency, absence of fault detection, and over drainage due to lack of shunt proactivity. There is a scientific consensus that the way forward to address these issues is through what is termed a smart shunt. The core component of this system is the mechatronic controllable valve. A design of a valve which utilises both the passive nature of the classical valves and the controllability feature of the fully automated valves is presented in this paper. The valve consists of a fluid compartment, a linear spring, and an ultrasonic piezoelectric element. The valve is designed to operate on a 5 V supply, to drain up to 300 mL/h, and it has an operational range between 10 and 20 mmHg. The design produced is considered feasible as it takes into consideration the multiple operation conditions associated with such an implanted system.Graphical

Effect of Combination Shunt Passive Filter Harmonic and Detuned Reactor on the K-Factor Changes of Transformer

This paper describes the impact of changes in harmonic distortion on the value of the transformer K-Factor. The transformer has a capacity of 1.5 MVA and a K-Factor value of 1 under normal conditions. Techniques were installed to reduce harmonic distortion, shunt passive filter, and detuned reactor. Several condition scenarios were created to compare changes in harmonic distortion's value to the K-factors value. Scenario 1, the transformer works in harmonic conditions. The K-factor value of the transformer becomes 3.947101, and the new capacity of the transformer that can serve the load becomes 1.27 MVA. Scenario 2, a passive shunt filter was installed in the transformer circuit. Shunt passive filter can reduce IHD-V and THD-V values on PCC but increase IHD-I and THD-I values on the load side. The k-factor value fell to 1.5775, and the new capacity of the transformer increased to 1.44 MVA. The novelty of this paper is in scenario 3, a combination of a passive shunt filter and a detuned reactor was installed in the transformer circuit. The detuned reactor can limit the harmonic current that enters the harmonic filter. As a result, all values, including IHD-V, THD-V, IHD-I, and THD-I fell below the maximum harmonic distortion limit. The k-factor value fell to 1.0361, and the new capacity of the transformer increased to 1.49 MVA. The existence of a detuned reactor has been able to increase the performance of the passive shunt filter. The impact of the detuned reactor for future research is that it can be used to protect important equipment in the electric power system.

Novel active-passive hybrid piezoelectric network for vibration suppression in fluid-conveying pipes

Given the failures like fatigue and fracture of the pipes conveying fluid induced by undesired dynamics and instability and the traditional passive damping cannot effectively attenuate the vibration in the low-frequency bands, this work introduces a novel active-passive control technique, namely, the hybrid piezoelectric network consisting of the piezoelectric layer, the circuit of the resistance and inductance, voltage source, controller, and sensor, which is attached on the cantilevered fluid-conveying pipes to suppress the vibration in wider frequency-bands. Built upon the location of the neutral axis in the segment of pipes is varied due to the integration of the pipeline and piezoelectric actuator, the governing equations of the fluid-conveying pipes attached with the hybrid piezoelectric network are established by virtue of Hamilton's principle in conjunction with the assumed mode method, and approximate analytical expressions of frequency responses are derived using the Laplace transform technique. The passive damping performance is carried out to achieve insightfully using the open-loop analysis based on the circuit of the resistance and inductance is set as the passive shunt characteristic, then the closed-loop features are also investigated according to the velocity feedback control. The numerical example illustrates the presented control method is effective and feasible to realize the vibration suppression on the pipes conveying fluid. Based on this, the optimal resistance and inductance are proposed through the theoretical analysis, which can further broaden the vibration attenuation.

Shunts vs networks: tuning and comparison of centralized and decentralized piezoelectric vibration absorbers

This work develops a unified modeling framework for piezoelectric structures controlled by passive shunts connected to a single transducer and/or networks interconnecting multiple transducers. A common tuning procedure for these different control approaches, termed decentralized and centralized approaches, respectively, is proposed. The generic model is then used to compare them in terms of vibration mitigation performance. It is shown that decentralization can be detrimental to performance in general. Digital vibration absorbers are then leveraged to realize the shunts and/or networks. In this regard, the proposed tuning procedure solely relies on characteristics that can be identified from the digital units of these absorbers. The theoretical developments are numerically and experimentally validated on piezoelectric beams.

Review on Microgrid Power Quality Improvement Using Active Power Conditioner

This paper discusses power system power quality issues and possible remedies using power electronics. Several worldwide standards for power quality control are briefly discussed, as well as some significant methods for analysis. Non-sinusoidal waveforms are introduced and assessed in an electrical circuit. The compensatory features and principles of operation of passive filters, shunt, hybrid, and series active power filters are presented. For each type of power filter, the topologies and control schemes of various power circuits are examined. Simulation and experiment are used to prove the compensating features of each topology with its corresponding control scheme. Harmonic current, power factor, and load unbalance can all be compensated for by the filter. Harmonic current, power factor, and load unbalance can all be compensated for by the filter. A power filter that has been employed there continuously monitors the load current and adapts to changes in load harmonics.

Model based investigation of reluctance force shunt damping—A numerical parameter study

An electromagnetic energy converter for vibration damping is studied. The device consists of a coil linked with a magnetic circuit with permanent magnetization and a variable air gap between the fixed magnet and a moving yoke. The reluctance force in the air gap causes magnet and yoke to attract each other. Passive shunts of the coil lead to a hysteresis between reluctance force and motion of the yoke causing damping. A numerical model is set up which describes the magnetic circuit by lumped elements. The nonlinear dynamic state equation of the magnetic flux is solved for harmonic air gap oscillation using the Harmonic Balance Method. Equivalent linear stiffness and damping of the flux-depending reluctance force are computed in order to study the mechanical behaviour of the system. Besides consideration of resistively shunted reluctance force dampers, deployment of a resonant shunt is proposed in order to amplify the damping effect. The influence of shunt parameters on the frequency-depending mechanical behaviour is investigated. Based on the frequency-depending equivalent damping, a suitable application for shunted reluctance force dampers is examined.

Passive control of multiple structural resonances with piezoelectric vibration absorbers

A novel sequential tuning procedure for passive piezoelectric shunts targeting multiple structural modes is proposed in this work. The control authority on each targeted mode can be quantitatively chosen ab initio and is shown to be limited by passivity requirements, which highlights the fundamental limitations of multimodal piezoelectric shunts. Based on effective characteristics of the piezoelectric system around resonance, electrical damping ratios and resonance frequencies are derived using well-established single-mode formulae from the literature, thereby fully specifying the characteristics of the shunt impedance. The proposed approach is numerically verified and experimentally validated on piezoelectric beams by emulating the shunt with a digital vibration absorber.

Vibration Suppression of a Composite Prosthetic Foot Using Piezoelectric Shunt Damping: Implications to Vibration-Induced Cumulative Trauma.

Energy-storage-and-return (ESAR) prosthetic feet have improved amputee mobility due to their efficient conversion of strain energy to mechanical work. However, this efficiency is typically achieved using light-weight, high-stiffness materials, which generate high-frequency vibrations that are potentially injurious if transmitted to biological tissues. To reduce the vibration which may cause cumulative tissue trauma, high-frequency vibration suppression by piezoelectric shunt damping patches on a commercial ESAR foot was evaluated. Two patches with either passive or active shunt circuits were placed on the foot to investigate vibration suppression during experimental tests where a plastic hammer was used to hit a clamped ESAR foot on the free end. Prosthesis bending moments at each modal frequency were obtained by finite element methods to identify piezoelectric patch placement. Both shunt circuits decreased vibration amplitudes at specific modes better than the no shunt case, but also increased the amplitude at specific frequencies. The vibration suppression performance of the active shunt circuit deteriorated at the second mode, while the vibration suppression performance of the passive shunt circuit deteriorated at all frequencies above the third mode. These results indicate piezoelectric shunt patches may be a viable strategy for decreasing vibrations of an ESAR foot, with active methods more efficient at suppressing high-frequency vibrations. Additional research is necessary to fine-tune the method for maximal vibration suppression. Overall, this study indicates that high-frequency vibration suppression is possible using piezoelectric patches, possibly decreasing the cumulative tissue damage that may occur with repetitive exposure to vibration.

An improved passivity enforcement algorithm for transmission line models using passive filters

This paper proposes a simple but effective method based on shunt passive filters to enforce passivity on a frequency dependent transmission line model for multi-conductor cables and overhead lines. The passivity enforcement algorithm is applied to a widely-used frequency dependent line model in EMT-type software, the Universal Line Model. The passivity violating regions of the transmission line model are identified using the frequency sweep method. The passive shunt series RLC filters are added to the nodes of the transmission lines to eliminate passivity violations. Examples of multi-conductor underground cable systems are presented to demonstrate the validity of the proposed approach.

PERFORMANCE ANALYSIS OF FUZZY LOGIC CONTROLLED HYBRID ACTIVE DC FILTER (HADF) FOR 12-PULSE HVDC CONVERTER

Transmission of power through High Voltage Alternating Current (HVAC) Transmission lines results in power losses in the transmission line, higher the length of transmission line higher the losses, furthermore cost of transmission line also increases with length. In order to maintain the voltage within the limits, reactive power also need to be transmitted over the same line which again increases the power losses. In order to overcometheabove problems, High Voltage Direct Current (HVDC) is preferred to transmit the power when the distance of transmission is above 500kM, which requires only one conductor for Monopolar Link and ground acts as return conductor. The converters used for conversion of power from ac to dc produce harmonics, which can be handled with the filters. In the proposed work a 12-pulse HVDC converterwith Hybrid Active DC Filter (HADF) consisting of 100 MVAR Shunt Passive Filter and Shunt Active DC Power Filtercontrolled by fuzzy logicis designed and simulated in MATLAB/Simulink, Shunt Active DC Power Filter handled the higher order harmonics and compensated the remaining reactive power in addition to passive filters.

Experimental validation of solar PV sustained ZSI based unified active power filter for enrichment of power quality

The deployment of power electronic devices has become a big concern for power quality in these days. The voltage stabilization of power distribution networks interconnected with Photo Voltaic (PV) is very critical in promoting the smooth operation of all linked devices in the distribution system. Voltage profile maintenance is one of the challenges in PV integration into the grid. Conventional devices such as passive filters, series and shunt filters, synchronous condensers, etc. are insufficient to alleviate numerous problems of power quality. The series compensator is used for voltage quality and the shunt compensator is used for current quality. Also, if these two problems of power quality are simultaneously mitigated, the device is used in the distribution system known as Unified Active Power Filter (UAPF). The shunt and series compensator of UAPF is equipped with a Z-source inverter(ZSI). This paper addresses voltage and current associated existing power quality concerns which including voltage sag, voltage swell, voltage and current distortion and simulates the UAPF device to alleviate these problems. The Unit Vector Template Generation (UVTG) with Improved Second Order Generalized Integrator (ISOGI) based Phase Locked Loop (PLL) is utilized for UAPF controller simulation and experimental results validated the proposed work.

Biomass Power Plant and its Harmonic Mitigation by Single Tuned Passive Shunt Filter

This paper presents the actual case study of a direct combustion biomass to electricity generation power plant. Conventional fuel sources used for generation of electricity may vanish in future hence biomass to electricity generation gives an important option. The development of biomass conversion technologies and their economic adoption has vast scope in India. In recent times / days electronically switched and nonlinear type of loads are used and applied by most of the consumers. When nonlinear types of loads are connected with supply, they introduce harmonics in the system, which produces so many bad effects such as increase in losses, resonance effect, malfunction of protective systems, saturation of magnetic core, decrease in efficiency etc. hence it is essential to mitigate the harmonics within the set limits. Traditionally single tuned passive shunt filters are most economical and efficient type of filters and are most widely used for almost all applications of harmonic mitigation. An analytical model of synchronous generator with nonlinear load is initially developed by using MATLAB. The simulation results with and without application of single tuned passive shunt filters are analyzed on power quality parameters such as VTHD and ITHD by using FFT analysis with achievement of harmonic mitigation.

Improvement in step resolution and response time of ultrasonic motor by using a piezoelectric resonant shunting circuit as damping control.

Ultrasonic motors can be driven by burst voltage to obtain micro-stepping motion, and the corresponding step size depends on the load and cycle number of the applied ac driving voltage in one burst. The rotor of the motor achieves a step motion through a process of startup-acceleration-deceleration-stop. To obtain a large torque (or thrust force) and quick startup, a large vibration amplitude of a stator and a high growth rate are desired; thus, a large mechanical quality factor and a high electromechanical coupling factor are required. However, the stator vibration decays for a long time before it stops because of low mechanical energy loss; meanwhile, the rotor moves a big step. Hence, there is contradiction between thrust force and resolution/response time. This paper presents a new drive method to improve the step resolution and response time while keeping the torque by damping control. By simply adding a switch and a shunting damp circuit and connecting the shunting circuit to ultrasonic motors at the end of a drive burst signal, the stator vibration attenuates more rapidly and the step size is reduced. First, the damping effect of the piezoelectric system with a passive resonant shunting circuit (a resistor and an inductor connected in series) on the free stator of a bar-type rotary traveling wave ultrasonic motor has been tested. Next, a drive circuit comprising electronic switches and the shunting circuit is designed and utilized for measuring the performance of the motor. Experimental results have well proven the proposed method.