Low-voltage Battery Research Articles

Health Indicator Development for Low-Voltage Battery Diagnostics and Prognostics in Electric Vehicles

Each electric vehicle (EV) requires a low-voltage (e.g., 12V) auxiliary battery to provide electric power to onboard electronic control units, lighting systems, and various sensors during power off. Therefore, when the low-voltage battery is in low state of health (SOH) or low state of charge (SOC), it may cause no-start events. The existing OnStar Proactive Alert service can effectively predict low SOC or low SOH events for low-voltage batteries in Internal Combustion Engine vehicles using cranking signals. However, it does not work for EVs since there is no cranking event. In this work, a diagnostic and prognostic solution for the low-voltage battery of EVs is proposed. Four novel health indicators (HIs) along with the decision-making system are developed based on equivalent circuit models. Furthermore, the selection process of appropriate HIs tailored to various operational states of the vehicle is described. The validation results based on GM test EV data have demonstrated the effectiveness and robustness of the proposed solution.

A Bridgeless Modified Switched-Inductor SEPIC High Power Factor Rectifier With Extended Voltage Transfer Ratio for Low Voltage Battery Charging Applications

A Bridgeless Modified Switched-Inductor SEPIC High Power Factor Rectifier With Extended Voltage Transfer Ratio for Low Voltage Battery Charging Applications

Heavy-duty vehicles with solar panels as a regenerative power source

Abstract Road transportation represents more than a third of all CO2-producing sources on Earth, being the main producer of greenhouse gas (GHG) emissions. Nowadays, continuous development of technology has reduced fossil-fuel consumption by integrating clean energy sources as a range extender. Solar energy has the largest potential of all renewable energy sources worldwide. The photovoltaic and energy storage research fields have grown exponentially during the last decade and, forced by the current energy crisis, had a great contribution to the hybrid solar vehicles (HSV) industry. Vehicle Integrated Photovoltaics (VIPV) comply with requirements on vehicles aesthetics, and they convert solar energy into electric energy to supply the low-voltage and high-voltage battery packs onboard HSV. Heavy-load road transportation by commercial vehicles equipped with PV-integrated modules or retrofit installation will contribute to global decarbonization. A study is done on a configuration of a heavy-duty vehicle with its cuboid cargo body covered with solar panels and a regulated driving route during different weather conditions [3]. The energy management system is designed to maximize solar energy conversion in order to reduce fuel consumption and extend the vehicle’s total driving distance.

Highly efficient corrosion inhibitor for low charge voltage and long lifespan rechargeable aqueous zinc-air battery

Hydrogen evolution, passivation and dendrite growth problems faced by zinc anodes of aqueous zinc-air batteries greatly reduce their cycle life and hinder their application in energy storage devices. Herein, a reversible, corrosion-resistant, and long-term stable cycle-life zinc anode is achieved by introducing zinc acetate and zinc gluconate into an alkaline electrolyte as corrosion inhibitors. Zinc acetate adsorbed on the surface of the zinc anode could be able to regulate the anode/electrolyte interface and thus inhibit the growth of dendrites, and zinc gluconate can reduce the charge voltage on the cathode to regulate the oxidation reaction and then prolong the cycle life, which eventually inhibit zinc anode corrosion. The additive package of zinc acetate and zinc gluconate provides a better performance. With addition of corrosion inhibitors, Zn||Cu cells show a high average coulombic efficiency about 94 %, and zinc-air batteries achieve a cycling lifespan of 297 h and low charge voltage of 1.7 V. This work provides a simple but practical guideline for high-performance zinc-air batteries.

Hedgehog-like NiMoSe microsphere arrays for efficient overall water splitting

We report a one-step hydrothermal method to synthesize hedgehog-like NiMoSe microsphere arrays on nickel foam (NiMoSe/NF), the morphology of which is determined by tuning the content of Ni2+ in the growth solution because Ni2+ can promote the growth of rod-like structure. Owning to the unique hedgehog-like microsphere structure composed of microrod arrays, NiMoSe/NF possesses a large catalytic active area for uploading more active sites, and is beneficial to electron transfer and gas precipitation during catalytic reactions. The synthesized NiMoSe/NF only requires an overpotential of 88 mV/190 mV to achieve a current density of 10 mA cm−2 with stability of 44 h/62 h for the hydrogen evolution reaction (HER)/oxygen evolution reaction (OER). When NiMoSe/NF is used as both the cathode and anode, the system can afford 10 mA cm−2 current density at low battery voltage of 1.50 V with a stability of 48 h. The work promotes the development of transition metal electrocatalysts for high-efficient splitting of water.

Design of fuzzy logic controlled zero voltage switching based interleaved high gain converter

The conversion of low level DC voltage to high level DC voltage at lower duty ratios with less ripple current at source side is a challenging task in the distributed generation systems. Active switched inductor (ASL) converter is a high gain converter and has a large amount of input ripple current due to the parallel charging of the inductors during on time of the switches and series discharge of the inductors during off time of the switches. This large input ripple current in the converter when used in distributed generation (DG) affects the life time of low voltage batteries and fuel cells, the efficiency of photovoltaic source, increases the size and losses in the filtering stages and decreases the power density of the converters. In this paper, soft switching of interleaved active switched inductor (IASL) through Zero Voltage Switching (ZVS) is designed to overcome the limitations of ASL. The performance is analyzed in terms of its gain, input current ripple, switching loss and efficiency. An M-type resonant switch is used to achieve soft switching through ZVS technique.A proper value of resonant elements (inductor and Capacitor) is designed to achieve ZVS to improve the efficiency. Regulated voltage of proposed converter is required in DG systems and is possible with closed loop control. Fuzzy Logic controller (FLC) is designed to regulate the voltage and its dynamic performance is analyzed for different load values and also for sudden changes in load. Hardware model of the proposed ZVS based IASL converter with FLC is implemented and the results are verified with simulation results obtained from MATLAB Simulink.

Design and Implementation of Single-Phase Grid-Connected Low-Voltage Battery Inverter for Residential Applications

Integrating residential energy storage and solar photovoltaic power generation into low-voltage distribution networks is a pathway to energy self-sufficiency. This paper elaborates on designing and implementing a 3 kW single-phase grid-connected battery inverter to integrate a 51.2-V lithium iron phosphate battery pack with a 220 V 50 Hz grid. The prototyped inverter consists of an LCL-filtered voltage source converter (VSC) and a dual active bridge (DAB) DC-DC converter, both operated at a switching frequency of 20 kHz. The VSC adopted a fast DC bus voltage control strategy with a unified current harmonic mitigation. Meanwhile, the DAB DC-DC converter employed a proportional-integral regulator to control the average battery current with a dynamic DC offset mitigation of the medium-frequency transformer’s currents embedded in the single-phase shift modulation scheme. The control schemes of the two converters were implemented on a 32-bit TMS320F280049C microcontroller in the same interrupt service routine. This work presents a synchronization technique between the switching signal generation of the two converters and the sampling of analog signals for the control system. The prototyped inverter had an efficiency better than 90% and a total harmonic distortion in the grid current smaller than 1.5% at the battery power of ±1.5 kW.

DC Cascaded Energy Storage System Based on DC Collector With Gradient Descent Method

With the continuous development of distributed energy, the energy storage system (ESS) is indispensable in improving power quality. Aiming at the application of large-capacity storage battery access to medium voltage dc power grid, a dc cascaded energy storage system based on the dc collector is proposed, and the characteristic, topology and control are presented in detail. In this scheme, the low-voltage storage batteries are accessed to medium voltage dc bus directly with dc collectors, which not only has higher efficiency, but also improves power density. Especially, the diversity of state of charge (SOC) is only reflected in the duty cycle of submodules (SMs), rather than the voltage deviation. Further, a variable angle carrier phase-shifted modulation with gradient descent method is discussed to eliminate the dominant current harmonics. By calculating the harmonic amplitude and solving the Jacobian matrix, the gradient that reduces harmonic current is obtained, and the optimal combination of the carrier phases is deduced by iterative calculation. Meanwhile, the method can be extended in the dc collector with any number of SMs to eliminate the dominant harmonics. Finally, the experimental prototype is built and the benefit of proposed solution is verified.

A Novel Tri-Mode Bidirectional DC–DC Converter for Enhancing Regenerative Braking Efficiency and Speed Control in Electric Vehicles

A bidirectional dc–dc converter is used to match the voltage levels between a low-voltage battery and a high-voltage traction machine in an electric vehicle. Using a conventional bidirectional converter with a standard voltage range, there is a limitation to the fine variation in the electric vehicle speed. During the regenerative braking process, when the speed decreases below a certain value, the generated voltage is insufficient to charge the battery, hence the regenerated energy cannot be stored. This paper proposes a novel bidirectional converter featuring three distinct operational modes: boost, buck and buck-boost. In the normal driving mode, it operates as a boost converter, providing double gain and accommodating a wide voltage range. During regenerative braking, the proposed converter switches to the buck or buck-boost mode based on the control algorithm. This adaptation is intended to either decrease the generated voltage to charge the battery effectively or to raise the voltage if it is insufficient for charging the battery. This configuration provides voltage stress of half the dc link voltage on the switches. This paper provides a comprehensive analysis of the proposed circuit, a detailed description of the control strategy with pulse generation logic for all switches and a mode transition algorithm. The simulation results of a circuit operating at a 1500 W power level are presented and compared with those of a standard bidirectional converter.

Design and Analysis of a Step-Up Multi-Port Converter Applicable for Energy Conversion in Photovoltaic Battery Systems

Aiming at the problems of large power fluctuations and poor stability in photovoltaic and other new energy power generation systems, a step-up multiport converter (MPC) that can simultaneously connect low-voltage photovoltaic cells, batteries, and loads (independent loads or power grids) is proposed in this manuscript. According to the possible operating conditions of the system, the working principles are described in detail. Theoretical analysis based on different working modes is presented and a hybrid modulation control method including pulse width modulation (PWM) and phase shift modulation (PSM) are applied to realize energy transmission between photovoltaics, batteries, and power grids. A simulation model is built in the PSIM environment to validate each working state of the system and mode switching function. Experiments are carried out on an experimental platform using the dsPIC33FJ64GS606 digital microcontroller as the control center, and the experimental results successfully verify the system function and PWM + PSM control efficiency.

A Modified Zeta Based High Power Quality Rectifier for Low Voltage Battery Charging Applications

A Modified Zeta Based High Power Quality Rectifier for Low Voltage Battery Charging Applications

Bridgeless Modified High-Step-Up Gain SEPIC PFC Converter Based Charger for Light EVs Battery

This study presents a two-stage on-board charger for light electric vehicles (LEVs) with low voltage battery (24-72V). The front-end of the charger has characteristics of high voltage conversion ratio and unity power factor operation achieved by a bridgeless high gain modified SEPIC converter. The high voltage conversion ratio enables the front-end to operate over a wide range of input voltages. At the back-end of the charger, an isolated positive output Luo DC-DC converter is employed to regulate the charging profile of the LEV battery under constant current (CC) and constant voltage (CV) charging modes. The presented charger operates in discontinuous conduction mode (DCM), which has dual advantages of having inherent feature of power factor correction (PFC) at the supply end along with significantly reducing the complexity of control mechanism, thereby reducing the cost and effort of control implementation. The operational analysis and design of the presented charger in DCM are covered in detail in this study and the same are further validated by means of simulations. A 650 W test bench setup is developed to authenticate the theoretical performance by means of experimental results. The experimental performance of the front-end is finally compared with other PFC topologies to highlight the merits and demerits of the presented charger.

Flyback converter employed non-dissipative cell equalization in electric vehicle lithium-ion batteries

The effective and dependable usage of rechargeable batteries has emerged as a central topic for automobile manufacturers in the wake of the rise of electric vehicle technology. When it comes to rechargeable batteries with high specific energy and specific power, lithium-ion battery technology is the most well-known. The low terminal voltage battery cells in the lithium-ion battery pack are linked in series to provide the necessary voltage for the electric vehicle system. The low charge cell in the string limits the usable capacity of the battery pack, though. Disturbances in the battery pack's charge are due to variations in manufacturing quality and to the unique operating circumstances of each individual cell. These inconsistencies cause a decline in usable capacity, a quickening of cell deterioration, and, most significantly, substantial safety issues including overcharging. The cell balancing controller is a critical component of the battery management system in all electric vehicle and hence performs a crucial function in extending battery life and ensuring the battery's safety. This paper presents a hardware-in-the-loop simulation of a RCD buffer included fly-back converter-based active cell equaliser for lithium-ion batteries in electric vehicles. With the equaliser, all the series-connected cells may be brought to a more even State of Charge. All of the MOSFETs employed in the proposed approach are selected for their low conduction loss. The suggested equaliser is able to produce equalization without the need for a switch driving circuit or sophisticated control method, allowing it to function automatically. The system's overall price is reduced, and the balanced circuit's complexity is considerably reduced. In-depth discussions on circuit configuration, operating principle, modeling, and design consideration are presented. Finally, both Matlab simulation results and Hardware-in-loop based experimental findings are offered to back up the claims that the suggested cell equaliser is both practical and effective.

Design and Optimization of High-Gain Bidirectional DC–DC Converter for Electric Vehicles

To better leverage and cope with the characteristics of low-voltage electric vehicle battery pack, this work optimizes the design of on-board bidirectional DC/DC converter. Based on the dual active half-bridge (DAHB) converter, combined with partial switch sharing, a high gain bidirectional DC/DC converter is proposed. This converter has 48-V and 24-V output voltage levels, and the multiple voltage levels, which are often required by new energy vehicles, are able to reduce the number of on-board converters. The theoretical part of this work analyzes the design process of the converter, and in parallel, establishes the mathematical models of transmission power, soft switching, current stress and reactive backflow loss. Under the condition of high gain, the system has good soft switching characteristics and low reactive backflow loss. In the experimental part, a prototype with an input voltage of 400V is built under an operating frequency of 100 kHz. The voltage of the two output ports is stable and a peak efficiency of 94.7% is achieved. The experimental results verify the validity of the theoretical analysis.

ДОСЛІДЖЕННЯ ДВОНАПРЯМНОГО ПЕРЕТВОРЮВАЧА ПОСТІЙНОЇ НАПРУГИ ДЛЯ ЗАСТОСУВАННЯ В СИСТЕМАХ НАКОПИЧЕННЯ ЕНЕРГІЇ

Electromagnetic processes in a bidirectional DC converter with the possibility of increasing and decreasing output voltage levels using an asymmetric inverter for a battery energy storage system when operating in difficult conditions with a short conversion period and determining its parameters are considered. Bidirectional DC converters are widely used in hybrid energy storage systems and in DC distribution power systems. This non-isolated bidirectional boost-buck converter is designed to control the flow of energy between sources with different voltage levels due to the use of low-voltage batteries in these systems. Thanks to the ability of these converters to quickly redirect electrical energy both in one and the other direction, it became possible not only to charge the battery from stationary sources of electricity, but also to charge the battery during the operation of the generator from the internal combustion engine and regenerative braking. The results of calculations of the prototype of a bidirectional DC converter with a 14 V battery, a 200 V DC bus and an output power of 3500 W are given. A prototype was made to confirm the possibility of rapid energy conversion. Ref. 9, fig. 6. Keywords: electric power storage systems, bidirectional DC voltage converter, fast energy conversion, hybrid electric vehicle.

A Single-Stage Charger for LEV Based on Quadratic Buck-Boost AC-DC Converter Topology

A single-stage AC-DC converter, which uses a quadratic buck-boost voltage gain, for LEVs' (Light Electric Vehicles) battery charging is presented in this work. Unlike conventional BCs (Battery Chargers), which employ transformer (low or high frequency) based approaches to charge low voltages LEVs' batteries, the presented charger utilizes transformerless single-stage power architecture. In order to realize desired charging of LEVs and to maintain proper transformerless voltage gain, the presented quadratic buck-boost AC-DC converter ensures high step-down gain characteristics between AC mains and low voltage battery packs. Besides realizing desired battery charging profile, the presented single-stage BC ensures high PQ (Power Quality) indices (low input current distortions and unity power factor operation) at the supply side. Notably, the presented quadratic buck-boost AC-DC converter exhibits an intrinsic power factor correction (PFC) feature at the AC input mains under discontinuous inductor current mode (DICM) operation, thereby, incurring minimum complexities during the control implementation, which further reduces the cost of the charger. The DICM operation facilitates negligible switch turn-on and diode reverse recovery losses, and therefore, ensures an improved conversion efficiency of the BC. Even if, the presented AC-DC converter employs two switching devices, the simultaneous switching of both switches shrinks the cost and complexity of driving circuitry even further. Finally, a comprehensive operational analysis, component selection criteria, and modelling of the presented quadratic buck-boost AC-DC converter-based LEVs BC are carried out and its performance is validated through a test bench set-up in a laboratory environment. Relevant results are presented to validate the efficacy of the presented quadratic buck-boost AC-DC converter for LEVs charging applications.

Kriging-Assisted Multi-Objective Optimization Framework for Electric Motors Using Predetermined Driving Strategy

In this paper, a multi-objective optimization framework for electric motors and its validation is presented. This framework is suitable for the optimization of design variables of electric motors based on a predetermined driving strategy using MATLAB R2019b and Ansys Maxwell 2019 R3 software. The framework is capable of managing a wide range of objective functions due to its modular structure. The optimization can also be easily parallelized and enhanced with surrogate models to reduce the runtime. The framework is validated by manufacturing and measuring the optimized electric motor. The method’s applicability for solving electric motor design problems is demonstrated via the validation process. A test application is also presented, in which the operating points of a predetermined driving strategy provide the input for the optimization. The kriging surrogate model is used in the framework to reduce the runtime. The results of the optimization and the framework’s benefits and drawbacks are discussed through the provided examples, in addition to displaying the properly applicable design processes. The optimization framework provides a ready-to-use tool for optimizing electric motors based on the driving strategy for single- or multi-objective purposes. The applicability of the framework is demonstrated by optimizing the electric motor of a world recorder energy-efficient race vehicle. In this application, the optimization framework achieved a 2% improvement in energy consumption and a 9% increase in speed at a rated DC voltage, allowing the motor to operate at desired working points even with low battery voltage.

RF Controlled Wind Energy Powered Vehicle

Abstract: An electric powered vehicle has a bank of batteries that runs the entire vehicle. This work focuses on charging the batteries of the vehicle on the run. This is done by capturing the wind that acts opposite of a moving car. There is always the flow of wind as long the cars moves with a speed. A wind turbine is mounted on the front of the vehicle to receive wind. The generator produces electricity from the wind and stores them in another battery. The vehicle moves with the pre-charged battery and a voltage sensing circuit is placed on one or more batteries of the vehicle to detect the drop in voltage. In such case the reservoir battery that gets charged through wind switches the position with the low voltage battery and continues to run the vehicle while the other battery gets charged. This process can go on until the vehicle comes to stationary. While one of the limitations of the electric vehicles is their short travel range compared to their excessive charging time. The travel range can be extended by charging the battery on the motion. This paper mainly focuses on the design of the wind powered car and to determine the power required for driving the system.

Mixed Current Control Strategy for Bi-directional Boost Converter Fed BLDC Drive

The speed of BLDC motor can be varied by applying PWM technique to inverter while the DC-link voltage is constant. Another approach is PAM technique in which the speed of motor is controlled by varying the DC-link voltage. The problem with PWM based drive is switching losses and also restriction in wide speed range operation when the drive is fed by low voltage battery. For wide speed range of operation, a high voltage battery or else a boost derived converter can be used in the front end of the inverter such that the DC-link voltages can be varied. By using boost converter, wide speed range control is possible along with the reduction of ripples in input battery current. This paper presents a mixed current control strategy which combines the inverter based (PWM) and the converter based (PAM) current controller, in addition to that the starting current is limited. The detailed mathematical analysis was derived for boost converter fed BLDC motor drive. The effect of proposed current control in the speed and starting current of motor is verified experimentally

Bi-directional non-isolated impedance converter for extra low-voltage battery system safety

Bi-directional non-isolated impedance converter for extra low-voltage battery system safety