Inductive Storage Research Articles

A Novel Single-Stage Boost Single-Phase Inverter and Its Composite Control Strategy to Suppress Low-Frequency Input Ripples

Low-frequency pulsating ripples exist on the input side of a single-phase inverter, which bring some adverse effects and harm to the inverter and photovoltaic power generation system. In order to suppress the low-frequency pulsating ripple and reduce the filter circuit parameters, a novel single-stage boost single-phase inverter is proposed, which can suppress low-frequency ripple. And a three-closed-loop compound control strategy that can suppress input low-frequency ripples under the limitation of an energy storage inductor current and buffer capacitor voltage is proposed. The circuit topology, control strategy, key circuit parameters design, system modeling, and simulation of the inverters are deeply analyzed and studied. Simulation and experimental results show that the inverter has a good ability to suppress input low-frequency ripples.

Electrically Exploded Current Opening Switch for Fast Transfer of Energy from an Inductive Storage to a Load

Electrically Exploded Current Opening Switch for Fast Transfer of Energy from an Inductive Storage to a Load

Dual-mode control magnetically-coupled energy storage inductor boost inverter for renewable energy

Dual-mode control magnetically-coupled energy storage inductor boost inverter for renewable energy

Output Ripple Voltage Analysis of Quadratic Buck–Boost Converters with Switched Inductor Network in the Entire Dynamic Range

In order to provide theoretical guidance for the design of quadratic Buck–Boost converter with switched inductor network, the minimum current flowing through the energy storage inductor L 3 is compared with the output current and zero, the working mode of the converter can be divided into the complete inductor supply in continuous conduction mode(CISM-CCM), the incomplete inductor supply in continuous conduction mode(IISM-CCM)and the incomplete inductor supply in discontinuous conduction mode(IISM-DCM). Within the given input voltage and load range, the working region of the converter is divided into five parts according to the different value of the inductor L 3. By analyzing the output ripple voltage of the converter in the five working areas, and the maximum output ripple voltage of the converter is obtained. Based on the relationship between the maximum output ripple voltage of the entire dynamic range and the value of the inductor L 3, it is pointed out that the output voltage ripple of the converter in CISM-CCM is the smallest and independent of the inductor L 3, and that the output voltage ripple in IISM-CCM and IISM-DCM is much larger and increasing with the decreasing of the inductor L 3. Meanwhile, it is concluded that the minimum inductance to guarantee the lowest output ripple voltage is the critical inductance between CISM-CCM and IISM-CCM. Finally, the experimental results verify the rationality and correctness of the theoretical analysis.

Solid Discharger for the Systems Forming a Current Pulse in Low-Impedance Loads of Inductive Storages of Electromagnetic Energy

Solid Discharger for the Systems Forming a Current Pulse in Low-Impedance Loads of Inductive Storages of Electromagnetic Energy

Wide voltage range and low current ripple bidirectional DC/DC converter

ABSTRACT Along with the prosperous growth of battery energy storage system being applied in renewable energy system, wide voltage range regulation and low current ripple bidirectional DC/DC converters attract much attention of researchers. Based on a basic boost–buck converter and voltage multiplying unit (VMU), this article proposes a two-stage DC/DC converter. The front stage is an input parallel output serial connected boost–buck converter and the back stage contains a dual-coupled inductors VMU. The storage inductors of the front stage aremagnetically coupled with those in back stage. Employing dual coupled inductors VMU can increase voltage gain while not increasing main switch voltage stress during step-up mode, which can widen the application scenarios. During step-down mode, a fully controlled method can obtain a greater step-down voltage ratio. Due to the interleaving control mode of the main switches, the current ripple of the battery side is lower when the converter works bidirectionally. The proposed converter has the advantages of widening voltage range regulation and lowering current ripple while avoiding extreme switch duty cycle. This article discusses theoretical step-up and step-down work mode of the proposed converter. Experimental results sampled from a 12 V/115 V prototype are presented to verify the analysis of the proposed converter.

A Novel Isolated High-Step-Up Interleaved Converter for Renewable Energy Systems

In this paper, an isolated high step-up interleaved converter for renewable energy systems is proposed. The input-parallel configuration introduced by two energy storage inductors, which can disperse the input current, reducing conduction losses and also improve the conversion efficiency. In order to improve the voltage gain and recover the energy stored in the leakage inductance, the auxiliary step-up structure is utilized in the proposed converter, that including an auxiliary inductor, an auxiliary capacitor, a voltage multiplier capacitor and two switches which serve to exchange the energy stored in auxiliary capacitors and inductors. On the secondary side, a voltage-doubler circuit is used to extend the voltage gain. Finally, a 48V-input, 400V-output and the rated power of 500 W prototype is implemented to verified the effectiveness of the proposed converter. The experimental results shows that the maximum efficiency is 95.97%, and the efficiency of full-load is 93.27%.

METHOD OF INCREASING EFFICIENCY, MEAN OF CONTROL AND TOOL OF ANALYSIS OF THE USE ENERGY OF POWER SOURCE PULSE LASER RANGE FINDER

The latest results of a series researches of the revealed paradox of energy balance disturb and its manifestations in electrical circuits are presented in order to increase the efficiency of the conversion of energy voltage direct current into pulsed energy of other forms, on the example of improving the use energy of the power source of pulsed solid-state laser range finder. It is show, that the efficiency of simultaneous conversion in a load with active linear or nonlinear resistance of the energy, which accumulated in the inductive and capacitive storage, can reach the efficiency of its accumulation. For this the first time offered the aperiodic mode of the transient process in the oscillating circuit use to combined the dual properties of inductive and capacitive energy storages and method of automatically switching their parallel connection during accumulation by them energy in series connection during conversion accumulated energy, particular, into optical pulses in the range finder. In total, proposed method of converting energy voltage direct current into pulsed energy of other forms, mean of objective control and tool of modeling and analyzing the use of energy primary power sources make up a set of measures for increasing energy efficiency separate nodes mobile devices of telecommunications, automation and robotics, what is especially actual in the existing conditions limited energy resources.

Maximum Power Point Tracking of Photovoltaic Module Arrays Based on a Modified Gray Wolf Optimization Algorithm

In this study, a modified gray wolf optimization algorithm (GWOA) was proposed to facilitate the maximum power point tracking (MPPT) of photovoltaic module arrays (PMAs). To increase the voltage conversion ratio and achieve a voltage boost through reduced duty cycles, a high-voltage step-up converter with a coupled inductor was used to replace the conventional energy storage inductor. To achieve global MPPT, the iteration parameters of the proposed GWOA were adjusted according to the slope of the PMA power–voltage (P–V) curve. According to the simulation results, the modified GWOA is more effective in MPPT than the perturbation and observation algorithm and conventional GWOA when multiple peaks appear in the P–V curve of a shaded PMA. In addition, the modified GWOA exhibits an improved tracking speed response and steady-state response.

An Maximum Power Point Tracker of Photovoltaic Module Arrays Based on Improved Firefly Algorithm

In this paper, an improved firefly algorithm (FA) was proposed for application on photovoltaic module arrays (PVMAs) with partial modules under shading so that the maximum power point tracking (MPPT) could be implemented. Firstly, a new model of high voltage step-up converter was developed for executing the MPPT of the PVMA. For the energy storage inductor of the developed converter, the architecture of the coupled inductor was adopted so that the converter switch did not need to operate under an excessive duty cycle, which could increase the voltage gain and reduce the ripple of the output voltage at the same time. To prevent shading on the partial modules within the PVMA and generate more than one peak on the power-voltage (P-V) output characteristic curve, where the conventional MPPT could only track the local maximum power point (LMPP) and reduce the output power of the PVMA, the maximum power tracker, based on the improved FA, was proposed in this paper. Such a tracker could perform an automatic online adjustment on the FA iteration parameters, according to the slope of the P-V output characteristic curve, for the PVMA and, at the same time, perform at 0.8 times of the maximum power point (MPP) voltage for the module array under standard test condition (STC), serving as the initial tracking voltage for implementing the global maximum power point tracking (GMPPT). Lastly, the actual test results were applied to verify that the proposed converter indeed contained a high voltage step-up and low-ripple output voltage. The improved FA could also track GMPP faster and further improve the power-generating efficiency of the PVMA.

Control strategy for the magnetic energy storage and transfer system (MEST)

The Magnetic Energy Storage and Transfer system (MEST) aims at improving the power handling in supplying the SuperConducting (SC) coils of fusion experiments. It is based on smart use of Superconducting Magnetic Energy Storage technology and allows the introduction of a certain degree of decoupling between the grid and the load. The MEST operation is based on the storage and transfer of the needed energy between the Load Coil (LC) and an additional storage inductor named Sink Coil (KC); the energy transfer is realized via capacitors switched by fully controllable semiconductors.This paper focuses on the control system of the MEST and proposes a control strategy, based on two decoupled control loops, with the aim both to guarantee the desired current on the load coil and the compensation of the system losses. A model of the MEST with the proposed control system has been developed to analyze the performance through numerical simulations. The control strategy and the simulation results will be presented and discussed in the paper.

Buck Boost Transformer Less in PV System with Grid Connected

For single-phase grid-connected solar PV applications, a novel single-stage buck boost trans formerless inverter (BBTI) topology is presented in this paper. Leakage currents are eliminated since the input PV source and grid neutral share a common ground in this topology. In addition, the buck-boost capability of the proposed topology ensures that the maximum power point is maintained throughout a wide range of input PV voltage variations. The fact that only one energy storage inductor is used in the proposed topology makes it symmetrical during both grid half cycles. Additionally, the proposed topology's two out of five switches operate at a line frequency, resulting in low switching losses, while the remaining three switches operate in any mode with low losses. To control the proposed inverter topology, a straightforward sine-triangle pulse width modulation strategy is outlined and analyzed across all operating modes. The 300W laboratory prototype is the subject of experiments, and all of the major findings are presented in the paper. These findings demonstrate that the proposed system offers higher efficiency with lower THD in output current.

High-Efficiency Flicker-Free LED Driver with Soft-Switching Feature.

A novel interleaved DC-DC buck converter is proposed to drive high-brightness light-emitting diodes (LEDs). The circuit configuration mainly consists of two buck converters, which are connected in parallel and use interleaved operation. Through interleaved operation, the power capability of the converter is doubled. Traditionally, two individual inductors are used in the two buck converters. The difference between conventional parallel-operated buck converters using two energy storage inductors and the proposed circuit is that the proposed circuit uses two small inductors and a coupled inductor that replace the two inductors of the buck converters. In this way, both buck converters can be designed to operate in discontinuous-current mode (DCM), even if the magnetizing inductance of the coupled inductor is large. Therefore, the freewheeling diodes can achieve zero-current switching off (ZCS). Applying the principle of conservation of magnetic flux, the magnetizing current is converted between the two windings of the coupled inductor. Because nearly constant magnetizing current continuously flows into the output, the output voltage ripple can be effectively reduced without the use of large-value electrolytic capacitors. In addition, each winding current can drop from positive to negative, and this reverse current can discharge the parasitic capacitor of the active switch to zero volts. In this way, the active switches can operate at zero-voltage switching on (ZVS), leading to low switching losses. A 180 W prototype LED driver was built and tested. Our experimental results show satisfactory performance.

Research on Active Overbalanced Control Strategy for Lithium-Ion Battery

In order to improve the voltage balancing effect of the lithium-ion power battery pack, a control strategy based on single-cell voltage overbalanced in the battery pack was proposed. In this method, the voltage of each battery is taken as the criterion of energy balance, and the analog switch and the energy storage inductor are used in the energy balance circuit. The PID control strategy of overequalization is proposed, which fully considers the self-recovery of voltage after the end of the charging process. The voltage balanced system of the lithium-ion power battery pack based on the voltage of a single-battery pack is realized, and the voltage maintains a stable equilibrium state after being balanced. The experimental circuit built in this paper verifies the effectiveness of the proposed method and gives the experimental waveform and data of the balanced charging module, which proves the scheme’s feasibility.

Single-Phase ZVS Quasi-Z-Source Inverter With High Voltage Gain

A single-phase zero-voltage switching (ZVS) quasi-Z-source inverter with a high voltage gain is proposed, and important conclusions are obtained through the in-depth analysis of the key technologies, such as the topology, control strategy, high-frequency switching process, voltage transfer ratio, resonant processes, and ZVS condition, and the design criteria of key parameters. The inverter is composed of an impedance network with a high voltage gain, a ZVS auxiliary network, a single-phase inverter bridge, and an output <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filter, adopting the unipolar SPWM control strategy with instantaneous feedback of output voltage and energy storage capacitor voltage. The impedance network is comprised of an energy storage inductor and two same diode–inductor–capacitor–capacitor cells; the ZVS auxiliary network includes a resonant inductor, a clamping capacitor, and an auxiliary switch, which provides the ZVS condition for power switches. The experimental results of a 1-kVA prototype verify that the proposed inverter features a high voltage gain, ZVS of all switches, high conversion efficiency, high output power quality, and strong load adaptability and has an important prospect in single-phase inversion with low input voltage or wide input voltage range.

Твердотельный разрядник для систем формирования импульса тока в низкоимпедансных нагрузках индуктивных накопителей электромагнитной энергии

The paper considers the use of a solid discharger with a cathode localized enhancement of electric field working together with an opening switch of an inductive storage to form a quick-rising current pulse in a low-impedance load. The physical factors bringing to an increase in pulse sharpening efficiency are specified. The discharger geometry variant is proposed. The technique for a determination of its parameters depending on the experimental requirements and conditions is described. The paper presents the results of the experiments on a stationary facility demonstrating a possibility to generate the current pulses with a rise front ~ 100 ns in the inductive loads ~ 10 nH. The obtained results allow giving a recommendation to use this type of dischargers to form multi-megaampere current pulses with submicrosecond rise front (up to ~ 100 ns) for the inductive energy storages and, in particular, for the explosive magnetic (magnetocumulative) generators., in the circuits with low-impedance loads.

Solid discharger for the systems forming a current pulse in low-impedance loads of inductive storages of electromagnetic energy

The paper considers the use of a solid discharger with a cathode localized enhancement of electric field working together with an opening switch of an inductive storage to form a quick-rising current pulse in a low-impedance load. The physical factors bringing to an increase in pulse sharpening efficiency are specified. The discharger geometry variant is proposed. The technique for a determination of its parameters depending on the experimental requirements and conditions is described. The paper presents the results of the experiments on a stationary facility demonstrating a possibility to generate the current pulses with a rise front ~100 ns in the inductive loads ~10 nH. The obtained results allow giving a recommendation to use this type of dischargers to form multi-megaampere current pulses with submicrosecond rise front (up to ~100 ns) for the inductive energy storages and, in particular, for the explosive magnetic (magnetocumulative) generators., in the circuits with low-impedance loads. Keywords: solid (condensed) dielectric, breakdown delay, overvoltage.

Optimized piezoelectric energy harvesting circuit using DC/DC converter

Some electrical devices, such as those harvesting energy from vibrations, deliver an AC output voltage that needs to be rectified. A DC / DC conversion stage is, in most situations, necessary for correct management of the recovered energy. This type of circuit makes it possible to raise or lower the voltage delivered by the generator. To some extent to match the impedance. The impedance match plays an essential role in the performance of the transducer, given that its optimum operating point can vary over time, and deviating from this optimum point can rapidly drop the harvested power.Many approaches proposed in the literature are based on switching converters. The operation of these converters is based on the switching of the current between storage elements, inductors and capacitors. The converters step-down or step-up, these have the advantage of allowing the adjustment of the ratio between output voltage and input voltage, which results in a controllable input impedance.In this study, we propose an architecture associating a rectifier and a Buck converter, allowing charging a battery from a piezoelectric transducer. The measurement of the battery charging current is used to define the duty cycle that maximizes the energy harvested. In this case, the DC/DC down converter is appropriate because the transducer provides a voltage higher than 45 V in open circuit, while the considered power range is from 1 to 120 mW. The authors show a 415% improvement in the recovered power, compared to the case of a direct load.

A Soft-Switching Interleaved Buck–Boost LED Driver With Coupled Inductor

In this article, a novel dc–dc light-emitting diode driver employing an interleaved converter is proposed and analyzed. The circuit topology mainly consists of two parallel buck–boost converters. A coupled inductor, which is composed of a magnetic core and two windings, is used to replace the energy storage inductors of the two buck–boost converters. This not only does not add any components, but also saves a magnetic core. The buck–boost converters are designed to operate near boundary conduction mode. Due to the characteristics of magnetic flux balance, the magnetic-excited current can be converted between the windings of the coupled inductor. By using the magnetic-excited current to release the charge stored in the parasitic capacitors of the active switches, these switches can fulfill zero-voltage switching <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> (ZVS) without the use of any auxiliary switches, active clamping circuits, or snubber circuits. Moreover, the freewheel diodes of both buck–boost converters can achieve zero-current switching <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> (ZCS). The steady-state analyses for different operation modes are provided, and the mathematical equations for designing circuit components are conducted. Finally, a 200-W prototype circuit was built and tested to verify the analytical predictions. According to the experimental results, all the semiconductor devices are operated at either ZVS or ZCS, and the circuit efficiency as high as 95.0% is measured. Satisfactory performance has verified the feasibility of the proposed converter.

Design of an Adaptive Boost Energy-Saving Fuzzy Control System Driven by the Finite State Machine

Aiming at the challenging problem of the traditional warp knitting machine electronic jacquard control system with complex structure of multiple circuit boards layered cascade, such as large physical space occupation, high power consumption, and independent high-voltage power supply voltage, we proposed an embedded circuit and control strategy design for the piezoelectric jacquard needle (PJN) with adaptive boost and energy recovery functions. Firstly, the electromechanical dynamics model of PJN was established. Secondly, the fuzzy PI double closed-loop control algorithm driven by a finite state machine is proposed. Thirdly, with the help of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), the PJN is integrated with the drive circuit. The drive circuit of PJN uses an energy storage inductor to replace the current limiting resistor of the traditional drive circuit, which can not only limit the forward charging current of the PJN and reduce energy loss but also can use the energy absorbed from the low-voltage power supply to adaptively boost the power supply of the PJN to the high voltage required for working conditions. The simulation results show that the new PJN drive circuit has an adaptive self-boost function. The PWM signal modulated by the fuzzy PI double closed-loop control algorithm can efficiently and accurately control the adaptive boost power supply and the voltage across the PJN. The mode of the circuit can be correctly switched through the sequential logic of the finite state machine and realize the energy recovery function.