Constant Output Voltage Research Articles

A 2.5m Long-Range IPT System Based on Domino Cylindrical Solenoid Coupler Compensated Respectively in Layers

In this article, a 2.5m five-stage inductive power transfer (IPT) system based on domino cylindrical solenoid coupler (CSC) compensated, respectively, in layers is proposed. The system is considered to be used as 220 kV post insulators application, transferring power for sensors and measuring instruments of smart grids. The distributed series compensation method is applied to double-layer CSC. Compared with the two types of parallel schemes, this method can significantly reduce the current of the main circuit. Compared with the concentrated series compensation method, this method can effectively reduce the resistance caused by the stray capacitance. The interaction between the post insulator and the magnetic coupling structure is analyzed. The circuit model of the system with constant voltage output characteristics is analyzed. A prototype with a maximum efficiency of 66.7% is built. When the power is transferred to a larger value of 77.8W, the efficiency can still reach 62%. Comparing with previous works, the wireless distance is extended while the efficiency is improved.

Active Disturbance Rejection Control Using Artificial Neural Network for Dual-Active-Bridge-Based Energy Storage System

The dual-active-bridge (DAB) converter has become a popular isolated solution to integrate energy storage systems (ESSs) and dc microgrids (MGs). However, constant power loads (CPLs) and pulsed power loads (PPLs) may reduce system damping and cause voltage oscillations in DAB converter-based ESSs (DAB-ESSs). An artificial neural network-based active disturbance rejection control (ANN-ADRC) is proposed to regulate constant output voltage quickly and accurately under different operating conditions. First, the ADRC controller is designed based on the small-signal modeling of the DAB-ESSs. Feedforward compensation and uncertainty estimations of the extended state observer (ESO) help to improve the dynamic performance and to reduce the number of current sensors. Then, after satisfying the conditions of stability analysis, the parameters of the ADRC controller are selected automatically via ANN. The ANN is trained with two inputs (ADRC controller parameters) and two outputs (performance indicators of the ADRC controller). The well-trained ANN can be used as a surrogate model to obtain the optimal solution of the objective function easily and quickly. The proposed ANN-ADRC algorithm with selected parameters is implemented and validated on the hardware experimental setup. The experimental results illustrate that the proposed controller can achieve fast dynamic performance under various operating conditions.

A Multirelay Wireless Power Transfer System With Double-Sided LCC Compensation Network for Online Monitoring Equipment

A multirelay wireless power transfer (WPT) system with the double-sided inductor-capacitor-capacitor (LCC) compensation network for the online monitoring equipment on the high-voltage transmission line is proposed. Constant-voltage (CV) or constant-current (CC) output characteristics is achieved. The proposed topology does not use ferrite materials, and the LCC compensation networks are only utilized at the transmitter and the receiver. Each relay coil is only connected in series with one compensation capacitor. Three working modes are proposed according to the resonance conditions of Tx compensation network, Rx compensation network, and compensating capacitances of relay coils. CC and CV output characteristics in each mode are analyzed and compared by simulation in terms of system output attenuation with load changes and frequency sensitivity. The parameter design process is given. A six-coil experimental prototype is built to validate the correctness and feasibility of the theoretical analysis.

Novel Design Method in Wireless Charger for SS Topology with Current/Voltage Self-Limitation Function

This study proposes a novel wireless power transfer (WPT) resonance compensation design method based on the SS topology with a self-limitation function that achieves fault tolerance without additional components when the secondary circuit is in a short and open state. Conventionally, WPT compensation topologies have constant current (CC) or constant voltage (CV) output characteristics. The CC and CV characteristics can lead to overvoltage and overcurrent, respectively. Several control systems have been proposed to counter this issue; however, they tend to increase the cost and weight of the system. The proposed topology has a self-limitation function that limits the voltage–ampere output. Here, the wireless charging system was designed after the parameters were obtained using the proposed analysis. The performance of the proposed design was verified by configuring a 400 W experimental prototype and comparing it with the conventional series–series (SS) topology. Experimental results indicated that the system could effectively limit the output voltage and current resulting from open-or short-circuit states.

Double Impact-Based Piezoelectric Energy Harvester for Low-Frequency Operation

This article presents a theoretical, numerical, and experimental study of a frequency upconverting (FUC) piezoelectric vibration energy harvester with a single low-frequency resonator that impacts twice per oscillation cycle on a single high-frequency unimorph generator. The model’s relevant physical aspects are specially designed to enhance the electrical output power over a wide-frequency range in the low-frequency excitation. The proposed double impact strategy allows obtaining a nearly constant output voltage, in contrast to typical upconverting mechanisms whose output voltage decays quickly in time. The device is safe from fatigue and can be used in high acceleration scenarios because the large displacements are limited by the generating beam, which acts as a natural stopper in an upward and downward directions. The prototype is designed to obtain a low value of optimal resistance with enhanced broadband performance below 25 Hz. The double impact FUC energy harvester’s performance is improved by adjusting the gap distance, the thickness of the generating beam, and the tip mass of the driving beam. The harvester reports 1428- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> peak output power at 20 Hz and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$400 ~\mu \text{W}$ </tex-math></inline-formula> of average power for a usable bandwidth from 17.5 to 22 Hz in health monitoring systems.

Analysis of Series-Parallel (SP) Compensation Topologies for Constant Voltage/Constant Current Output in Capacitive Power Transfer System

This paper analyzed the four series-parallel (SP) compensation topologies to achieve constant current (CC) and voltage (CV) output characteristics and zero phase angle (ZPA) input conditions with fewer compensation components in the capacitive power transfer (CPT) system. There are three main contributions. Firstly, the universal methodology of SP compensation topologies was constructed to achieve CC, CV output, and ZPA conditions. Secondly, four specific SP compensation topologies were investigated and summarized, including double-sided LC, double-sided CL, CL−LC, and LC−CL topologies. Their input–output characteristics are provided, and system efficiency is analyzed. Thirdly, the CL−LC and LC−CL topologies were proposed to realize ZPA conditions under CC and CV output without any external regulating circuit. A CV output LC−CL experiment prototype was implemented to validate the theoretical analysis.

A Reconfigurable Half-Bridge Compensation Topology-Based WPT System With Constant Current and Constant Voltage Outputs

A reconfigurable half-bridge compensation topology is proposed in this brief for automatic guided vehicles (AGV) wireless charging system. Considering the cost and reliability, a simple and reconfigurable structure without extra passive element and additional relay is developed, the reconfigurable topology could realize the shift from inductor-capacitor-capacitor-inductor-capacitor-capacitor (LCC-LCC) topology to series-inductor-capacitor-capacitor (S-LCC) topology, and further achieve load-independent constant current (CC) and constant voltage (CV) outputs, full design freedom for current and voltage gain. Accompanying with a special switching strategy of mode transition, the proposed reconfigurable circuit could realize smooth cutting off of inductor current without spike across switch. Moreover, module of zero-current could be saved in the proposed topology. The proposed circuit has less switches and could achieve zero phase angle (ZPA) operating and zero voltage switching (ZVS) in the whole charging process, which allows the lower cost and power losses. An experimental prototype is established to validate the feasibility of the reconfigurable half-bridge compensation topology and switching strategy.

Research and Design of Misalignment-Tolerant LCC–LCC Compensated IPT System With Constant-Current and Constant-Voltage Output

It is well known that loads of inductive power transfer systems are often energy storage devices. The major benefit of an LCC–LCC compensation topology is that without the additional compensation elements and control methods, the load-independent constant current (CC) and constant voltage (CV) outputs, required by energy storage load, can be achieved at different resonant frequencies. However, the misalignment between two coils at the transmitting and receiving sides is inevitable and can lead to the variation of the resonant frequency in CC or CV output. Therefore, a unique design approach to the LCC–LCC compensation topology is proposed in this article. With the presented method, the resonant frequency, at which load-independent output characteristics can be also implemented, is constant and unaffected by the coupling coefficient, whether in CC mode or CV mode. Furthermore, the transmission gain, which is only impacted by the coupling coefficient, can be conveniently modified by the conventional phase shift control in two modes. Finally, a 120-W prototype is designed to verify the validity of the theoretical analysis. The output current and output voltage fluctuate by only 2.4% and 1.0% in the coupling coefficient range from 0.23 to 0.3 and the large load range, according to experimental results.

Analysis, Design, and Validation of a Decoupled Double-Receiver Wireless Power Transfer System With Constant Voltage Outputs for Industrial Power Supplies

Unwanted cross-couplings greatly hinder the development of double-receiver wireless power transfer (WPT) systems. Whenever the air gap changes or misalignment occurs, cross couplings disrupt the system stability. This article investigates a magnetic coupler for a double-receiver WPT system, which dramatically suppresses the unwanted cross-couplings. Two types of undesirable couplings are significantly reduced by using orthometric DD coils and Q-shaped coils. First, the unwanted couplings between receivers can be eliminated, validated by the measured coupling coefficient <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AB</sub> = 0.003. Therefore, two receivers can work independently. Second, the unwanted couplings among the source coil and receivers can be eliminated ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1A</sub> = 0.003 and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1B</sub> = 0.003), resulting in load-independent constant voltage output. Compensation networks can also be designed straightforwardly. In addition, the inverter can achieve zero phase angle, alleviating volt-ampere rating and increasing efficiency. Thanks to the presented structure, this coupler design process is efficient because the decoupling is from the shape rather than turns. Also, it can be easily generalizable to other output voltage or power levels since turns can be changed to meet different charging demands. Validated by a laboratory prototype, experimental results successfully show remarkable agreement with the theoretical analysis, ensuring 72 V load-independent constant output voltages. It also realizes a 90.16% maximum measured overall dc–dc power transfer efficiency with 12 cm air gaps when delivering 518.4 W to two 20 Ω loads.

Selective Harmonics Elimination Technique for Artificial Bee Colony Implementation

In this research, an Artificial Bee Colony (ABC) algorithm based Selective Harmonics Elimination (SHE) technique is used as a pulse generator in a reduced switch fifteen level inverter that receives input from a PV system. Pulse width modulation based on Selective Harmonics Elimination is mostly used to suppress lower-order harmonics. A high gain DC-DC-SEPIC converter keeps the photovoltaic (PV) panel’s output voltage constant. The Grey Wolf Optimization (GWO) filter removes far more Photovoltaic panel energy from the sunlight frame. To eliminate voltage harmonics, this unique inverter architecture employs a multi-carrier duty cycle, a high-frequency modulation approach. The proposed ABC harmonics elimination approach is compared to SHE strategies based on Particle Swarm Optimization (PSO) and Flower Pollination Algorithm (FPA). The suggested system’s performance is simulated and measured using the MATLAB simulation tool. The proposed ABC approach has a THD level of 4.86%, which is better than the PSO and FPA methods.

A Unique Design Approach of Double-Sided LCC Compensated IPT System for Misalignment-Tolerant Characteristic

For double-sided LCC compensation topology, it is not easy to maintain the output current and output voltage constant over the variation of coupling coefficient and load. Consequently, in this article, a unique design approach is presented. With the presented method, whether during a constant current output procedure or constant voltage output procedure, the resonant frequency maintains constant and cannot be affected by the coupling coefficient and load condition. In addition, the transmission gain is kept constant in different misalignment by the phase shift modulation. Zero voltage switching with the minimum reactive current can be implemented by the switch-controlled capacitor (SCC) regardless of the coupling coefficient and owing to the constant phasor of the current flowing the SCC, the control system of SCC is greatly simplified. Finally, a 60 W prototype is designed to verify the validity of the theoretical analysis. From the results of the experiment, when the coupling coefficient range is between 0.13 and 0.2, the fluctuation factors of output current and output voltage are only 0.5% and 1.0%, respectively.

Constant Current and Constant Voltage Charging of Wireless Power Transfer System Based on Three-Coil Structure

Constant current (CC) and constant voltage (CV) charging are two charging stages for li-ion batteries in an electric vehicle wireless charging system. Based on the three-coil structure, this letter proposes a novel reconfigurable topology to achieve CC and CV charging. The transmitting coil is split into two windings with one winding having a turn number much smaller than the other. The two windings are fully compensated and connected to the corresponding inverter phase. The system can be reconfigured to perform as the two-coil structure with a CC output or as the three-coil structure with CV output. Unlike existing methods, the working frequency is fixed and only one relay is utilized to achieve the shift of CC and CV charging, which has the advantages of simpleness and low cost. An experimental prototype with 94.4% maximum efficiency is implemented to validate the proposal.

Enhancement of Wireless Power Transfer for Automated Guided Vehicles Considering Disturbance Suppression

This article proposes an enhanced wireless power transfer (WPT) for automated guided vehicles (AGVs) considering disturbance suppression. The study is motivated because existent resonant methods may induce unexpected disturbances, affecting the efficiency of power transfer and disturbing the voltage gain. This paper is, therefore, focused on the suppression of disturbances as well as the realization of an effective wireless power transmission. Moreover, by considering that the output voltage is often affected by misaligned charging, the system design has included the gain-frequency control along with an early detection of coil misalignment. It is anticipated that through this proposed approach, the constant-voltage output can be achieved while the efficiency of power transfer is improved as well. To validate the practicality of this approach, the hardware prototype is tested with a significant decrement of disturbance interference during the wireless power transmission, supporting the feasibility of the method for AGV charging applications.

A FPGA Based PI Adaptive Sliding Mode Controller for PEM Fuel Cell with Boost Converter

Proton exchange membrane (PEM) is one of the most popular fuel cells for renewable energy production, and this paper presents a DC/DC boost converter structure to improve energy efficiency. To achieve high output power as well as constant output voltage, a combined method consisting of proportional-integral controller and adaptive sliding mode technique is designed. Also, due to the use of adaptive technique, the proposed technique has the ability to cover the effects of uncertainty with an unknown high limit and in addition to improving the quality of output power and voltage of PEM, it eliminates permanent tracking error and guarantees closed loop system stability. To show the operational implementation capability and flexibility of the method, FPGA has been used, which in addition to showing real-time performance, provides the ability to execute the controller at high speeds. Operationality and the possibility of practical implementation of the planned scheme on the existing systems provide the possibility of increasing the efficiency of energy extraction without further investment. The stability of the closed-loop system is achieved using Lyapunov technique and the results of simulation and comparison indicate the optimal performance of the system under the planned scheme and high efficiency in comparison with existing approaches.

DC-DC Converter with Active Switched LC Network for PV System Along with MPPT

To get maximum power from Photo Voltaic (PV) panel, a DC-DC converter is operated with an active switched LC-network and a fuzzy controller, which boosts the output voltage by utilizing Maximum Power Point Tracking (MPPT). In areas where solar energy is abundant, PV systems offer a low-cost source of electricity. Non-Polluting and low maintenance are two advantages of a PV system. There are several factors that can reduce the output of solar energy, including irradiance, temperature, and partial shading in the cells. A DC-DC converter with active switched LC networks can be used to provide constant output voltage. As the power outcome of the PV system is variable, Perturb and Observe (P and O) MPPT procedure obtains maximum output power. The output of P and O MPPT is compared with Fuzzy Logic Controller (FLC) MPPT and the results are presented.

AC-DC DAB Converter with Power Factor Correction

AC-DC conversion is required in many applications, and in some of them isolation is strictly required, certainly while maintaining characteristics such as a high power factor and low input current THD. In this paper, an AC-DC converter, comprising a full-bridge diode rectifier and a dual-active-bridge (DAB) converter, is utilized to fulfill these characteristics. The used modulation makes the converter behave as a resistive load, maintaining the output voltage constant while achieving a high power factor and low input current THD. The operation of the converter is simple, as only two voltage sensors are required, and no inner current loop is utilized. A low-power prototype was experimentally tested to corroborate the proposal.

Design of intelligence‐based optimized adaptive fuzzy PID controllers for a two chamber microbial fuel cell

AbstractThe output voltage of microbial fuel cells (MFCs) needs to be controlled effectively to improve the operating efficiency of MFC system against the load variations, disturbances, and uncertainties. The output voltage control is purposed to provide the MFC with an appropriate amount of fuel required to maintain the stability of output voltage. In the applications, the MFC output voltage can be requested to track the variable reference voltage or to track the constant output voltage under changing conditions such as load change. For this purpose, two adaptive fuzzy PID (FPID) controllers powered by optimization algorithms were designed in this study to keep the output voltage value of the MFC at the desired values. This study extends the previous works by using optimization algorithms, such as particle swarm optimization (PSO) and gray wolf optimization (GWO) algorithms, to adjust fuzzy logic parameters, which are used for tuning Proportional‐Integral‐Derivative (PID) controllers. The optimization‐based adaptive FPID controllers play an active role in efficient, fast, and robust tracking of the reference voltage value with its adaptive structure. The designed adaptive control algorithms were tested under different cases, which involve the variation of the reference voltage and load conditions. The results show that both of these controllers can effectively control the output voltage of a MFC by regulating the flow rate of the fuel. In addition, the performances of the designed controller strategies according to the results obtained vary according to the reference signal. While PSO‐based FPID gives more successful results for positive step changes, GWO‐based FPID gives more successful results for negative step changes. These two control strategies show more efficient, robust, successful, and faster performances compared to the traditional PID controller.

Real-Time Frequency Stabilization of Standalone PV System with SMC

This paper aims to obtain suitable control for the Standalone Photo Voltaic (SAPV) system to meet consumer demands in weather conditions. A SAPV system is developed with a solar array with Maximum Power Point Tracking (MPPT), a Boost converter, and an inverter. This system uses controllers for maximum power output tracking, constant DC output of the Boost converter, and constant output voltage and frequency with Pulse Width Modulation (PWM) control mode. MPPT, boost converter, and inverter controller parameters are designed and tuned, respectively. Proportional gain (Kp) and Integral gain (Ki) values and the Sliding Mode Method (SMC) tune the controller parameters. The innovative aspect of this work is to propose a standalone PV system with controllers based only on the sliding mode control approach. Moreover, the current controller provides an output current of high quality with a THD of 1.6 %. Effectiveness and robustness of the proposed scheme modeled and simulated under OPAL-RT real-time Software in Loop (SIL) platform with MATLAB Simulink under fast variations of irradiance and temperature. Various analyses have been carried out for examining the proposed Sliding Mode Controller-based standalone photovoltaic system.

Self-Operating Flyback Converter for Boosting Ultra-Low Voltage of Thermoelectric Power Generator for IoT Applications

This article presents a novel self-operating flyback converter to boost the ultra-low voltage produced by thermoelectric power generator (TEG). The proposed converter uses dual transformer, one for low-voltage startup and other to extract power from TEG. The use of separate transformer provides high-voltage transfer ratio, reduces high series resistance loss, and brings down the input impedance of circuit. The copper wire wounds ferrite toroid core transformer provides very low series resistance and negligible core loss, which improves the circuit efficiency. This boost converter operates with an input voltage range of 22–300 mV and provides maximum output power of 0.073 – 147 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\rm{mW}}$</tex-math></inline-formula> correspondingly. The peak efficiency of 68% with output power of 1.32 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\rm{mW}}$</tex-math></inline-formula> (voltage ∼1.83 V) is achieved at an input voltage of 50 mV. For regulated output voltage, a feedback loop is used to keep output voltage constant during sudden voltage rise of TEG. The proposed circuit uses discrete components, ferrite toroid core, and PCB, which has lower cost than available energy harvester module, which uses energy harvesting ICs, discrete components, and tiny transformer. The lower startup voltage, higher output power, and voltage with high conversion efficiency of this boost converter maximize the applications potential of the TEG as a portable power source for Internet of Things (IoT) devices.

When the Supply Voltage is Dynamic

Voltage regulators usually serve the purpose of generating a constant regulated output voltage. By means of control loops, a stable and precise supply is generated from an unregulated input voltage. What purpose, then, does dynamic voltage scaling (DVS) serve?