4 - 2-Wire virtual remote sensing for voltage regulators: Clairvoyance marries remote sensing

The versatility of switched mode DC/DC Converters plays a vital role in power electronic converters technology by the virtue of its high conversion efficiency and reliable output voltage, moreover the design aspects of these converters are able to maintain the regulated output voltage even though input side voltage and output side current varies. In this paper a soft-switched, AC link DC to DC Converter proposed and closed loop voltage control is furnished to maintain the output voltage against the changes in input voltage and output current. However special features like zero voltage turn-on and capacitor restrained turn off can be realized by operating the resonant AC link of this converter in soft switching mode, these special features minimizes the switching losses developed on switches. In the proposed converter, the soft switching is realized through inductor current control. Concurrent ON and OFF time control based pulse technique is employed to achieve both closed loop voltage control and inductor current control. Simulations were performed in PSIM to evaluate the proposed converter in a illustrative manner.

The sample and hold effect, or quasi-digital (discrete) behaviour, of constant-frequency peak current-mode control (PCM) is pulse-width modulated DC-DC converters is presented in a manner consistent with the physical behaviour of the circuit. This approach develops a transfer function using control theory that captures the quasi-digital behaviour encountered when the current control loop is closed in PCM. The new transfer function accurately captures the current loop behaviour, leading the way for a compete linear time-variant system circuit for PWM DC-DC converters. This work improves upon previous derivations by remaining true to the physical behaviour of the circuit while resulting in a rational transfer function that can be used in a multiple loop complete linear system circuit to accurately predict converter behaviour due to changes in input voltage, output current, and reference voltage.

In electrical power systems, the insulator is the material that determines whether the electrical energy can be supplied or delivered to a place of excellent quality and does not harm the human and the environment around such high voltage electrical conductor devices. In testing leakage current in the laboratory, current and voltage changes in input and current changes and output voltages change very quickly, making it difficult to detect with the usual measuring device. For that required software to simulate the test. One method used to test the insulation resistance of the insulator material is the Inclined Plane Tracking (IPT) method. That is a method used to represent the leakage current on the surface of an insulation. The insulation and leakage resistance simulation in this test is performed by Multisim 14 software by simulating the insulation resistance with a potentiometer that changes resistance when a leak current occurs in the test. The resistance is increased step by step to know the parameters of current and voltage at the time of testing. In this simulation testing is done in stages, so it can be known Source Voltage, Input Voltage, Input Current, Leakage Current and Output Voltage. Simulation using Multisim 14 software can represent insulation resistance, leakage current and output voltage that can be used to obtain replacement resistance (Rp), leakage current (Iout), output voltage (Vout), alternating current (Iloss) and replacement voltage (Vloss). Simulation Software Proteus can simulate data received in the form of analog into digital data. Further processed according to the data required.

Currently, the existing grids are no longer able to cope with the requirements of the modern digital economy. In this regard, the role of unconventional sources of electricity, such as solar panels and wind farms, has increased. The growing role of direct current occurs due to the transition of the automotive industry from an internal combustion engine to an electric motor, as well as due to an increase in the service life and capacity of batteries. However, existing grids do not integrate well with receivers and sources using DC for the operation, which leads to a decrease in the quality, reliability of power supply and economic benefits. The way out of this situation is the transition from traditional to smart grids, which need to search for new methods, devices and solutions that meet the following rules: coordinated operation between DC and AC circuits with the ability to integrate batteries and charging stations; maintaining the quality of electricity in various operating modes, including off nominal ones; collection, conversion into digital form and transmission of information about the state and operating mode of the substation technological equipment and systems in real time operation; flexibility and reliability in the distribution and generation of electricity; high economic feasibility; self-diagnostic functions to ensure the detection of equipment and systems failure with an accuracy of a single module (block). At the same time, a classical transformer cannot cope with the assigned tasks; its disadvantages are given in this article. One of the solutions to this problem is the use of solid-state transformers - semiconductor AC power converters. The paper presents topologies and areas of application of classical AC and DC networks, their disadvantages. It is shown that with the development of direct current sources and consumers, problems arise with the integration of different types of current and voltage levels associated with the number of conversion steps and the quality of electricity. A block diagram of smart power supply networks based on a solid-state transformer is given with a description of what increases the overall efficiency of the network, the quality and flexibility in the distribution of electricity while reducing the number of conversion steps. The topologies of single-stage, two-stage and three-stage solid-state transformers are given and the areas of their application in different systems are shown. It has been established that for smart power supply networks, the most suitable is a three-stage topology of a solid-state transformer, which makes it possible to implement galvanic isolation with two DC-links, which will provide flexibility in switching power supply from DC to AC and vice versa, as well as increase the efficiency of the entire system as a whole.Mathematical modeling of the operation of a three-stage three-phase solid-state transformer for a symmetrical three-phase active-inductive load is presented. The system has output current and voltage feedback and automatic voltage regulation on the second DC-link. The tracking loop is implemented by changing the angle of block modulation in the controlled inverter and rectifier, which are part of the dual active bridge of a three-stage solid-state transformer. The controller is a proportional-integral controller. The graphs of the current and voltage changes when the load is switched on and off are given. It is shown that the voltage drop is insignificant and is almost completely compensated by the stored reactive energy in the reactive elements of a solid-state transformer.The applications of solid-state transformers, their advantages and disadvantages, as well as ways to eliminate these disadvantages are described in the article. The obtained results have shown the feasibility of using solid-state transformers in smart grids, in alternative energy, charging stations for autonomous devices of medium and high power, for energy distribution and in other areas.

A change in voltage at the power node of a gate can significantly increase the delay of a logic gate [32, 498, 499], degrading the overall performance of a system [34]. Since different circuits are affected differently by a drop in the power supply voltage, the power distribution network should be designed to satisfy multiple constraints. The voltage level for those gates along the critical path can tolerate the least voltage degradation, whereas the gates along a noncritical path may satisfy speed constraints despite a higher voltage drop [289]. Circuits, such as a phase-locked loops and voltage controlled oscillators (VCOs), are highly sensitive to changes in the power supply voltage [500]. Alternatively, digital logic circuits can tolerate much higher variations in the power supply voltage. The voltage level of a power distribution network across an entire IC is typically maintained within 10 % degradation, while for a PLL, the voltage level should satisfy a maximum 2 % voltage degradation. To satisfy these constraints, the current supplied to the PLL is filtered by a DC-to-DC converter or a large on-chip decoupling capacitance placed near the PLL [501]. The decoupling capacitors and DC-to-DC converters however consume large area and can dissipate significant power [338].

The reliability of automatic control systems depends on the reliability of its elements in particular computing equipment. Computing equipment is a constant consumer of power from the network During the operation of computing technology, there are often dynamic changes in the voltage in the power supply network-dips and interruptions. Dips and interruptions are one of the main problems in terms of noise immunity of computing equipment. The results of studies of the noise immunity of computing equipment with dynamic changes in the power supply voltage are article presents.

This article presents an onboard magnetic integration-based wireless power transfer (WPT) system for misalignment-tolerant and stable charging of unmanned aerial vehicles (UAVs) with a lightweight and compact receiver (Rx). The onboard Rx and integrated compensation coils are coupled with an asymmetrical transmitter (Tx) coil to enhance the power transmission capacity and achieve misalignment tolerance. The secondary integrated-based compensation topology and its tuning method, which neutralize the coupling between the Rx and compensation coils, are elaborated to maintain the high-order topology performance with zero phase angle (ZPA) and constant current (CC) output. Furthermore, the topology operates stably in the whole misalignment-tolerant area of the asymmetrical coils. Finally, a WPT prototype is built to verify the performance of the studied methodology in both load variation and position deviation configurations. The output current changes by only ±2.5% when the load resistance varies from 5 to 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> . The proposed onboard magnetic integration-based WPT system allows ±150-mm landing deviations of UAVs.

This paper discusses a converter with a new strategy as a solution for converting 3-phase AC electrical energy from a wind turbine permanent magnet synchronous generator (PMSG) into DC electricity with more stable power due to the increasing demand for DC electrical energy. Three level dc-dc converter (TLDDC) was chosen because it can convert higher DC voltage and current compared to conventional converters. The problem arises because the TLDDC is operated to convert the power output of the wind turbine PMSG in an open loop system. The problem is that the converter cannot adjust the voltage and current according to the load requirements. Therefore, open-loop systems must be converted to closed-loop and usually use only single control. A single control is ineffective because it can only control voltage or current. This control cannot control voltage and current simultaneously. When the load is changed, the output voltage or current changes. From these problems, this study proposes a new strategy double control system that utilizes the PI dual control strategy for voltage and current. Based on the simulation and hardware implementation, this double PI control performance has been tested and measured with good results. The results of this study indicate a stable voltage at 48 Volt DC and a stable TLDDC output current according to load requirements with a pure DC output signal and lower ripple even though the speed of the wind turbine PMSG is always changing.

In respect to the difficulties in power supply for online monitoring equipments at high voltage side, a new design of adjustable and rechargeable induction power supply is presented. A microprocessor is used as the central control unit, which can achieve the intelligent management and control of different modules of the proposed device. The experimental results show that reliable and stable power output can be obtained in the situation of large current variation. Introduction The security and stability of the high voltage transmission lines are very important in the development of smart grid. As a result, different kinds of auxiliary devices are installed on high voltage transmission lines to improve the capability of condition monitoring [1]. However, due to the electrical isolation of safety requirements [2], the electronic monitoring equipments installed on the high voltage side can not be directly powered from the low voltage side. Therefore, the power supply has become one of the key technologies which restrict the development of online monitoring systems. The traditional power supplies, for example, solar energy [3], are unable to provide the monitoring equipments an all-weather, continuous and stable power supply. The induction power supply at high voltage side can work in harsh weather and provide stable and continuous output [4], which makes it an ideal choice for online monitoring equipments to solve their energy supply problem. However, since the current of the transmission lines varies in a wide range, it is crucial how to ensure that the induction power supply device has a stable and reliable output with a wide range of current fluctuation. It is necessary to ensure that the power supply can provide sufficient driving power to the online monitoring equipment when the current of the transmission line is small [5]. It is also needed to ensure that when large current flows in the transmission line, a sustainable and stable power supply still can be obtained. Therefore, a new design of adjustable and rechargeable induction power supply at high voltage side is studied. The proposed induction power supply can produce reliable and stable power supply in the condition of large current variation. The Structure of the Proposed Power Supply Fig. 1. The overall framework of the proposed induction power supply The proposed induction power supply consists of the power capture module, the rectifier module, the over-voltage protection module, the voltage regulator module, the backup power management 4th International Conference on Machinery, Materials and Computing Technology (ICMMCT 2016) © 2016. The authors Published by Atlantis Press 1195 module and the microprocessor control unit (MCU), as shown in Fig. 1. With the MCU, the entire device can be intelligently controlled to produce a stable DC voltage output even with a large current variation in the transmission line [6]. The details of each module of the proposed induction power supply are presented as follows. Power Capture Module. The structure of the power capture module is shown in Fig. 2. The actual current in the high-voltage transmission lines keeps changing. In order to adapt to the dynamic current changes, there are multiple taps at the CT coil in the secondary side. Different taps correspond to coils with different numbers of turns. With the sampling resistor in the rectifier module, the MCU can achieve a real-time control on the number of coil turns. When the current in the transmission line is too large, the current at the secondary side also becomes large. The MCU controls the relay 1 and then the coil 1 will be connected to the circuit in order to reduce the current at the secondary side. When the current in the transmission line is in normal variation, the MCU controls the relay 1 and then the coil 2 is connected. Finally, if the current in the transmission line is too small, then the backup battery may be switched on to power the equipment. Such a design makes the proposed device having efficient power capture capability over a wide range of current variations. Fig. 2. The structure of the power capture module Rectifier Module. Rectifier circuit DB107 is used in this design. RC filter and LC filter are connected in parallel. A transient suppression diode TVS, which plays the role of over-current protection, is inserted between the rectifier circuit and the filter. The selected TVS is SMF45A, which has a breakdown voltage of 75 V and a cut-off voltage of 45 V. Fig. 3. The structure of the rectifier module Voltage Regulator Module. The voltage of the DC output of the rectifier module is 7.5 V – 76 V. The role of the DC-DC voltage regulator module is to convert this wide range of input voltage into a stable but adjustable output voltage. In our design, the step-down voltage converter MAX5035BASA is chosen as the core unit of this module. It has high efficiency and wide input voltage range up to 76 V. Its output voltage is fixed to 5 V. Fig. 4 shows the circuit of this module.

The electric power system consists of static load, lump load, and motor. A large industry requires a large induction motor to run its production. However, the state of this induction motor harms the electric power system. The starting current on the motor is so high that it can be 5 to 10 times the nominal current. On the other hand, the motor absorbs much power from the electric power system and results in a voltage drop on the bus. This paper aims to improve the voltage drop on the bus and reduce the starting current of the induction motor. The analysis in this paper uses a transient curve of changes in voltage and starting current with time. Starting an induction motor with the Direct online (DOL) method as the basis for determining the voltage drop and the starting current of the induction motor. Furthermore, using the Capacitor Bank method, Fault Current Limiting (FCL), and Static Var Compensator (SVC) improves transients of voltage drop and motor starting current. All the results of these methods are compared to find out which method is the best.

This paper investigates the behaviors of Boost DC Chopper used in Photovoltaic energy systems where the solar irradiation changes during the day time causing current and voltage changes. Varying the solar irradiation causes output chopper voltage changes in order to keep working at maximum extracted solar power. The chopper voltage changes leading to variable duty cycle operation of chopper switch and causes a significant change in switch losses in terms of the dissipated power. In addition to that the chopper behaviors are studied when the chopper voltage is boosting up to a predetermined reference value leading to a significant change in chopper current, voltage, duty cycle and occurred losses. A mathematical model for chopper performances and switch losses is derived, and a simulation model using Matlab/ Simulink platforms is conducted to follow the chopper behaviors. Simulation results for concreteSUNPOWER panel type SPR-315E-WHT-D with 315 Watts peak indicates that during the daylight time transistors are exposed to complicated changes in their current, voltage and dissipated power. Furthermore changing the output voltage according to load requirements causes heavy stress on the transistor in terms of current, oscillations and losses as well. Simulation results show that there are optimized values of irradiation, chopper voltage and duty cycle where the transistor losses are minimized. In addition to that, projecting the transistor losses over the daylight time at a given irradiation rate shows how these losses vary among the year, and the amount of energy dissipated across the main chopper switch which is around 2970 Whr/yr for the present case. Furthermore, the conducted simulation also shows the occurred in the transistor behaviors when solar irradiation changes, and can be serving for further studies.

Transient dynamic DC electrical systems are often characterized by response time, amount of damping, and dynamic behavior of outputs in terms of input functions. This investigation correlates some of these standard responses in terms of nonequilibrium entropy generation rates to illustrate the concept of thermodynamic equivalence of metastable DC electrical systems. A resistor, inductor, capacitor (R, L, Ca, respectively) series circuit is subjected to a direct current (DC) step load change in voltage and the response is characterized using standard methodologies and compared/contrasted to the thermodynamic approach in which the metric is entropy generation rate. It is determined that metastable equilibrium is equivalent to the rate of change of entropy generation rate with respect to temporal rate of change in voltage of the dissipative resistor component. Using combined 1 st and 2 nd Laws of Thermodynamics, the total entropy generated is directly related to the thermal waste energy of the circuit.

ELECTRIC arc furnaces are desirable loads for power systems, and are becoming more and more used for producing high-grade alloy steels, as well as for other types of steel. The authors believe that the data in this article will be of value and assistance to others in the solution of similar problems. It is necessary in connecting large electric arc furnaces onto power systems that it be done in such a manner that neither the voltage changes, caused by the violent and rapid load swings of these furnaces, will interfere with other load of the furnace customer nor be permitted to reflect back into the system in such a manner as to interfere with service to adjacent customers. Also precautions must be taken so that such widely fluctuating loads will neither interfere with the operations of any of the equipment on the power system nor interfere with any interconnection with adjacent power companies. Further, precautions must be taken so that voltage regulation caused by large short-time loads will not be too great.

An efficient, organized and pressure tolerant electronic design is required to carry power to a 192-meter-long ocean acoustic coherent hydrophone array developed at North-eastern University. This oil filled linear towable large aperture hydrophone array is densely populated. The array consists of eight sub-sections, of which five are acoustic containing 160 hydrophone elements, two are non-acoustic sections, containing depth and heading sensors, and one vibration isolation module (VIM). This underwater acoustic array receives its power from a 5000W Power Supply housed on a research vessel (RV) or ship. The 300VDC output generated from the power supply travels through a 600-meter-long tow cable before it reaches the in-house designed main power board in the hydrophone array, bucking the voltage down to three independent 48V power rails. Multiple voltage rails were used to reduce current draw and voltage drop seen down the long-twisted pair of 16-gauge wires, feeding four other in-house designed power boards; 24V, 12V, 12V/-12V and 5V. During in-air operational testing while under high power producing conditions, thermal run-off was seen on the main power board. Although this is not critical for this application, precautions were made to allow for seamless testing. A commercial off-the-shelf (COTS) heat sink was cut and thermally epoxied around the main power integrated circuit (IC). Combining this with oil, which acts as a heat sink and the length of the array, an effective heat reservoir was produced. Detailed research and design were instrumental in the component selection, schematic and layout phases of this design to create a reliable, resilient, and cost-effective system. Future improvements and paths forward will also be discussed to improve reliability, energy efficiency and robustness.

Mismatched deformation in a bilayer composite with rigid coating on a soft substrate results in complex and uniform topographic patterns, yet it remains challenging to heterogeneously pattern the upper coatings with various localized structures. Herein, a heterogeneous, 3D microstructure composed of Ti3C2Tx titanium carbide (MXene) and single-walled carbon nanotubes (SWNTs) was fabricated using a one-step deformation of a thermally responsive substrate with designed open holes. The mechanically deformed SWNT-MXene (s-MXene) structure was next transferred onto an elastomeric substrate, and the resulting s-MXene/elastomer bilayer device exhibited three localized surface patterns, including isotropic crumples, periodic wrinkles, and large papillae-like microstructures. By adjusting the number and pattern, the s-MXene papillae arrays exhibited superhydrophobicity (>170°), strong and tunable adhesive force (52.3-110.6 μN), and ultra-large liquid capacity (up to 35 μL) for programmable microdroplet manipulation. The electrically conductive nature of s-MXene further enabled proper thermal management on microdroplets via Joule heating for miniaturized antibacterial tests. The s-MXene papillae were further fabricated in a piezoresistive pressure sensor with high sensitivity (11.47 kPa-1). The output current changes of s-MXene sensors were highly sensitive to voice vibrations and responded identically with prerecorded profiles, promising their application in accurate voice acquisition and recognition.