Electric Vehicle Inverter Research Articles

A New Generalized Multisource Inverter for Electric Vehicles Controlled by Model Predictive

A New Generalized Multisource Inverter for Electric Vehicles Controlled by Model Predictive

Drive Control using Multilevel Inverter for Electric Vehicle Application: A Hybrid SCSO-SNN Technique

This manuscript proposes a hybrid method for drive control using a multilevel inverter (MLI) for electric vehicle (EV) applications. The proposed technique is the joint execution of spiking neural network (SNN), and sand cat swarm optimization (SCSO), hence it is named as SCSO-SNN technique. The primary goal of the proposed technique is to improve the speed tracking performance and, energy efficiency and lessen the torque ripple of the EV. The set of control signals is generated by SCSO and the SNN is used to forecast the optimal control signal of the cascaded multilevel inverter (CMLI). The proposed technique is implemented in the MATLAB software and is evaluated their performance with various present methods. The results show that the proposed method can achieve better performance than current techniques based on speed tracking, energy efficiency, and torque ripple. The proposed method enhanced the total efficiency of the system (96%) and reduced the torque ripple (0.5%) when contrasted with current techniques like Genetic Algorithm (GA), Spotted Hyena Optimizer (SHO), Particle Swarm Optimization (PSO). The proposed method shows a mean of 1.269, a median of 1.212, and a standard deviation of 0.015, indicating high stability and consistency. It also demonstrates lower switching losses (0.159 W) and conduction losses (0.370 W) compared to existing methods, underscoring its superior energy efficiency and effectiveness.

Current Sharing Analysis and Evaluation of Parallel DC-Link Capacitors in Vehicle Motor Drive

In electric vehicle inverter systems, the DC-link capacitor bank becomes a critical obstacle to high power density due to its large volume. DC-link capacitor bank commonly adopts a multi-core parallel structure. The challenges exist in the current sharing of parallel capacitor cores because of the imbalance of stray parameters in the busbars. A current sharing analysis method aiming at thermal stress for capacitor banks in high-power-density inverters based on the characteristic matrix is proposed in this paper. First, the design basis of DC-link capacitors is given theoretically. Then, the complex coupling impedance model between multiple ports on capacitor busbars is mathematically derived by the matrix method, revealing the current resonance phenomenon of parallel capacitor cores affected by stray parameters. Next, three capacitor banks are evaluated by the proposed current sharing model. The influence of capacitor core arrangement and terminal position on current sharing is explored, which can guide capacitor banks’ high-power-density structure and heat dissipation design. Finally, an experimental platform is built with customized capacitor samples. The experimental results are consistent with the analysis results of the model, verifying the proposed method.

Capacitor sizing of three‐level neutral point clamped voltage source inverter for electric vehicles: Effects of modulation and motor characteristics

AbstractA three‐level neutral point clamped (3L‐NPC) voltage source inverter (VSI) topology can be advantageous in electric vehicles with a high DC‐link voltage and a high switching frequency. A bulky DC‐link capacitor is not an option; thus, the DC‐link capacitor's sizing considering the traction system characteristics is an important design step. This paper investigates how the DC‐link capacitor size of a 3L‐NPC VSI gets affected by the combination of the interdependent characteristics of an electric drive, such as its power factor, modulation index, current, and fundamental frequency, with the effects of the modulation methods. Five pulse width modulation (PWM) methods, of which three of them have an active neutral point potential control, are compared in terms of their neutral point potential (NPP) oscillations. Then, the size of the DC‐link capacitor is determined for each PWM method so that the NPP ripple is kept under desired limits at all operating conditions. It is shown that both the modulation technique and the electric machine characteristics influence the capacitor size. For example, electric machine design modifications can introduce more than a 30% reduction in capacitor size. Finally, DC‐link and NPP oscillations with different PWM methods are experimentally validated in a scaled‐down 3L‐NPC inverter.

A Novel Control Scheme for Traction Inverters in Electric Vehicles With an Optimal Efficiency Across the Entire Speed Range

A Novel Control Scheme for Traction Inverters in Electric Vehicles With an Optimal Efficiency Across the Entire Speed Range

Reducing the DC-Link Voltage Ripple by Optimized Pulse Patterns to Increase the Power Density of Traction Inverters in Electric Vehicles

Reducing the DC-Link Voltage Ripple by Optimized Pulse Patterns to Increase the Power Density of Traction Inverters in Electric Vehicles

Voltage lift technique-based quasi Z-Source inverter for electric vehicles functioning

Voltage lift technique-based quasi Z-Source inverter for electric vehicles functioning

Optimizing New Power Switch Technology

Power switches are critical components in power conversion for a wide variety of applications, including DC-AC inverters for electric vehicles (EVs), solid state breakers, and energy storage devices. Improving the efficiency and performance of semiconductor power switch components can have wide benefits, improving the efficiency and accelerating deployment of these applications. Compared to conventional power switches, such as insulated-gate bipolar transistors (IGBTs), the B-TRAN™ bidirectional power switch from Ideal Power offers significant improvements in efficiency, reducing power losses by 50% or more depending on the application. With its higher efficiency, B-TRAN results in less heat being generated and thus has significantly lower thermal management requirements. In addition, a single B-TRAN™ replaces multiple conventional power switches for bidirectional applications. Beginning in mid-2020, Ideal Power teamed with QP Technologies, a leading provider of microelectronic packaging and assembly services, to package their B-TRAN switches in various TO packages (a wide range of small-pin-count packages often used for discrete parts such as transistors or diodes). The development work started with TO-247, then moved TO-264 packages, and finally transitioned to a custom direct-bond copper (DBC) solution. To achieve a high-reliability design, QP Technologies and Ideal Power focused on developing die and packaging designs based on flip-chip technology in lieu of wirebonding to maximize the life cycle of the product. This paper investigates the challenges, solutions and finally the fabrication of the first double-sided B-TRAN device.

High power T-type-based multi-level inverter for electric vehicles

This paper presents an extension of a 5-level T-Type inverter to a high-power multi-level inverter that can be implemented in electric vehicles and trucks. The proposed inverter possesses several advantages over standard topologies such as Neutral Point Clamped, Flying Capacitor, and Cascaded H-bridge. The main advantages are a low number of components, an estimated lower price and weight, smaller dimensions, and the implementation of only one DC voltage source per phase. The proposed topology can be implemented for any required odd number of voltage levels. Due to the estimated reduced dimensions and weight, the proposed topology is especially suitable for electric transportation applications. The operation of the proposed topology was validated for 9- and 13-level configurations under PD, POD, and APOD PWMs. The simulation results show the inverter’s practicability for supplying motors of electric trucks.

Vibration and noise characteristics of an inverter for electric vehicle application

Noise, Vibration & Harshness (NVH) is one of the key parameters associated with comfort of an automobile. An Electric Vehicle (EV) consists of transmission driven by electric motor which ultimately gets its power or current supply from inverter. As per Electric vehicle architecture, motor ranks first followed by transmission and inverter in terms of NVH performance. The function of an inverter is to convert DC current from battery source to 3-phase AC current which goes to electric motor. Torque and speed characteristics of motor is dependent on current and voltage supply from inverter. Hence it is important to assess NVH characteristics of inverter as well. In this paper, vibration and acoustic performance of a standalone EV inverter have been studied by testing it at different vehicle operating conditions. Ideally the output 3 phase AC current from inverter should contain only electrical frequency, but it is observed that AC current contains harmonics in the form of linear combination of electrical frequency and switching frequency. From this study, observations from NVH tests on an EV inverter is highlighted in frequency range where relatively high vibration and noise levels were present.

Application of novel double-layer micro-jet heat sinks for energy-efficient thermal management of motor inverters in electric vehicles

The relentless advancement in electronics miniaturization and performance has birthed a tremendous amount of heat flux, demanding effective dissipation techniques. Thermal effects pose a significant hurdle in the thermal management of electric vehicles (EVs) and having advanced cooling techniques in place is vital. To tackle this, the present study numerically evaluates the cooling attributes of two novel double-layer micro-jet heat sinks (DLMJHSs) to address the thermal management of insulated-gate bipolar transistors (IGBTs) in the motor inverters of EVs. The numerical analyses are carried out for Reynolds numbers ranging from 5000 to 25,000, IGBT heat fluxes of 100, 200, and 300 W/cm2, and different configurations of DLMJHSs. The potential of using nanofluids is assessed by employing Al2O3–water nanofluid with different volume fractions of 0.8% and 1.7%. The finite volume technique is implemented to solve the equations and the turbulence closure is modeled using the k-ԑ model. Results show that HS #2 provides a 10.2% higher convective heat transfer coefficient leading to a 7.44 ℃ lower baseplate temperature than HS #1. Besides, HS #2 prevents the occurrence of high-temperature spots owing to a more uniform temperature distribution in comparison with HS #1. HS #2 demonstrates the most uniform temperature distribution, with a Coefficient of Variation of only 0.00993 and a maximum heat transfer coefficient of 80.5 kW/m2 ℃. The heat sink’s baseplate temperature drops by increasing either the Reynolds number or the volume fraction. The baseplate temperature declines by up to 6.94 ℃ using a nanofluid volume fraction of 1.7% compared with only the base fluid. A minimum Reynolds number of 15,700 is required to prevent overheating at the peak heat flux. The performance evaluation criterion (PEC) is higher than 1 for Re ≤ 15,000.

Optimized 750V SiC MOSFETs for Electric Vehicle Inverter Operation

We report an AEC-Q101-qualified 750V, 15 mΩ planar SiC MOSFETs with a long short circuit withstand time (SCWT) of > 9μs at VDS=400V and VGS=15V and a low specific on-resistance (RON,SP) of 2.1 mΩ.cm2 at VGS=15V designed for xEV traction inverter applications. The RDS(on) at VGS=15V increases from 15mΩ at 25 °C to 21 mΩ at 175 °C. A low turn-on (EON) and turn-off (EOFF) switching energy loss of 95.5μJ and 67μJ at IDS=75A, VDS=400V was measured at 25 °C. The gate oxide lifetime at worst case operating fields of 5MV/cm is >> 20 years.

Single-Phase Jet Impingement Cooling for a Power-Dense Silicon Carbide Power Module

The adoption of silicon carbide (SiC) devices in the electric vehicle (EV) industry is increasing due to their superior performance over silicon devices. SiC devices enable further miniaturization of EV inverters, increasing their power density, which results in thermal management challenges. In this paper, the limits of single-phase jet impingement cooling are explored for an automotive SiC power module. We propose embedding pin fins in the direct-bonded-copper (DBC) substrate of the power module package using laser powder bed fusion additive manufacturing. The thermalhydraulic performance of the DBC-embedded pin fins is compared against folded fins that are directly soldered to the DBC substrate. A heat conduction analysis was conducted on a SiC package to determine the target heat transfer coefficient (HTC) for the heat sink. A water-ethylene glycol (WEG) jet impingement on the proposed concepts was studied using unit-cell models to achieve the target HTC. The studied designs put emphasis on the reliability and manufacturability requirements of the automotive industry. The thermal performance of DBC-embedded pin fins outperformed the DBC-soldered folded fins. The performance of the DBC-embedded pin fins is benchmarked against WEG-based cooling systems of commercial EVs. With the proposed cooling solution, we have shown a pathway of reducing the specific thermal resistance by 75% compared to BMW i3 thermal management system without any penalty on pressure drop or parasitic power.

A Sensor-Based System for Fault Detection and Prediction for EV Multi-Level Converters.

Power electronic converters and alternating current motors are the actual driving solution applied to electric vehicles (EVs). Multilevel inverters with high performance are modern and the basis for powering and driving EVs. Fault component detection in multilevel power converters requires the use of a smart sensor-based strategy and an optimal fault analysis and prediction method. An innovative method for the detection and prediction of defects in multilevel inverters for EVs is proposed in this article. This method is based on an algorithm able to determine in a fast and efficient way the faults in a multilevel inverter in different possible topologies. Moreover, the fault detection is achieved not only for a single component, but even for several components, if these faults occur simultaneously. The detection mechanism is based on the analysis of the output current and voltage from the inverter, with the possibility of distinguishing between single and multiple faults of the power electronic components. High-performance simulation programs are used to define and verify the method model. Additionally, with this model, harmonic analysis can be performed to check the correctness of the system's operation, and different fault scenarios can be simulated. Thus, significant results were obtained by simulation on various topologies of multilevel converters. Further, a test bench was developed in order to verify some failure situations on a three-level inverter.

Numerical Study on Cooling Performance Characteristics of 22 kW Traction Inverter Using MHD Pump-Based Cooling System

The transportation sector is sharply shifting towards electric vehicles (EVs) to reduce environmental issues and the energy crisis. To enhance the driving range and performance of EVs, the integral parts of EVs are being developed with higher energy densities and compact structures. Traction inverters are one of the important parts of EVs which are continuously updating to higher power densities with smaller sizes. This has led to issues of high heat generation, which causes the performance degradation and failure of traction inverters. Therefore, an efficient cooling strategy needs to be proposed for the effective thermal management of traction inverters in EVs. In the present work, the magnetohydrodynamics (MHD) pump-based cooling system is developed for the thermal management of traction inverter for EVs. The cooling performance of traction inverters is investigated using a MHD pump-based cooling system with water and ferrofluid as coolants. The outlet velocity, inverter maximum temperature, and Nusselt number are numerically simulated as the cooling performance characteristics for various operating conditions of inlet velocity, magnetic field intensity, voltage, and volume fraction of ferrofluid. The coupled numerical model is developed using COMSOL Multiphysics commercial software to simulate the cooling performance of a traction inverter with an MHD pump-based cooling system under various conditions. The MHD pump improves the cooling performance of a traction inverter for ferrofluid cooling over water cooling. The cooling performance of the traction inverter improves with an increase in inlet velocity for both water and ferrofluid cooling. However, with an increase in voltage, magnetic field intensity, and volume fraction, the cooling performance of the traction inverter improves only for ferrofluid cooling. The outlet velocity, inverter maximum temperature and Nusselt number in the case of water cooling are 4.03 mm/s and 7.02 mm/s, 49.65 °C, respectively, whereas that in the case of ferrofluid cooling are 40.96 °C, 15.35, and 18.49, respectively. Further, the cooling performance improves for ferrofluid cooling at a magnetic field intensity of 0.4 T and volume fraction of 10% with outlet velocity, inverter maximum temperature, and Nusselt number approach to 12.08 mm/s, 32 °C and 21.43, respectively.

Impact of Dimensions, Apertures and Terminals on Stray Inductance of the Laminated Busbar

This paper presents a systematic investigation of the impact of physical parameters such as dimensions, apertures and terminals, on the busbar inductance. A planar laminated busbar with copper conductors and a polyamide insulator is studied using a 3D FEM (Finite Element Modelling) based simulation software. The impact of dimensions such as conductor length, width and thickness, depth of insulator, the effects of aperture number, size, position and connection terminals on the busbar inductance are examined. The magnetic flux density, current density involved and its dependence on the self and mutual inductance of the laminated busbar is analyzed. Laminated busbars provided lower inductance with decreased conductor length, thickness, aperture diameter and depth of insulator. Also, the increased width of the busbar is of the essence for the design of a low inductance busbar. Low inductance laminated busbars are highly beneficial in power converters, powertrain inverters in electric vehicles, photovoltaic converters.

EVALUATION OF ELECTROMAGNETIC FIELDS IN HUMAN BODY EXPOSED TO INVERTER OF PURE ELECTRIC VEHICLE.

On the basis of the basic principle of electromagnetic dosimetry, the paper studies the electromagnetic exposure of a passenger's body to a compound electromagnetic field caused by the combined action of DC and AC bus currents of a pure electric vehicle inverter. By building an electromagnetic model of a pure electric vehicle body, adult human body and inverter, the finite element method is used to calculate the magnetic induction intensity(|B|), induced electric field intensity(|E|) and induced current density(|J|) of the compound electromagnetic field to the human trunk and central nervous system in the driver and front seat passenger. The numerical results are compared with the exposure limits defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The fields are well below the safe exposure limits defined by ICNIRP.

A High-Gain Multilevel dc–dc Converter for Interfacing Electric Vehicle Battery and Inverter

An isolated multilevel bidirectional dc–dc converter is presented in this article to interface the low-voltage (LV) battery and the high-voltage (HV) propulsion inverter in electric vehicles. The proposed topology achieves a HV step-up ratio in the motoring mode by reconfiguring two split capacitor half-bridge circuits in series/parallel through the symmetrical modulation of a voltage bidirectional, two quadrant switch. This reconfiguration generates a high-frequency multilevel voltage output at the dc-bus side of the inverter, which reduces the output filter volume. The dc-bus voltage is regulated by the duty cycle modulation of the intermediary switch in the motoring mode, simplifying the sensing and control. During regenerative braking, the converter is operated with phase shift modulation between the HV half bridges and the LV full bridge to regulate the battery voltage. The presented modulation strategies achieve zero voltage switching for the full-bridge devices over a wide load range. A comprehensive analysis of the proposed multilevel converter in motoring and braking modes along with the design constraints and soft switching boundary conditions is presented in this article. Detailed experimental results on a 1.5-kW laboratory prototype are presented to verify the design approach and illustrate the converter performance.

Design of a Single-Stage Transformerless Buck–Boost Inverter for Electric Vehicle Chargers

This paper details the design and implementation of a single-stage transformerless buck–boost inverter for electric vehicle (EV) chargers. Being different from conventional H-bridge inverters, the proposed inverter operates like buck–boost dc/dc converters instead of buck dc/dc converters. As a consequence, the advantages of a buck–boost dc/dc converter, i.e., the arbitrary relationships between its input voltage and output voltage, are still applicable to the proposed inverter. Specifically, it remains in normal operation even when the peak ac output voltage is higher than the dc-link voltage. Simulation results are finally presented to illustrate its effectiveness.

A SiC-Based Liquid-Cooled Electric Vehicle Traction Inverter Operating at High Ambient Temperature

This paper describes the design process of a high-power-density 100 kW (34 kW/L) traction inverter for electric vehicles, operating at an ambient temperature of 105 °C. A detailed thermal analysis is performed based on the thermal behavior of the switching devices, and the results are used to estimate the semiconductor device junction temperature and to determine the requirements of the cooling system to achieve the target power level. A high-temperature gate drive board aiming for reliable system operation in electric vehicles is developed. An overcurrent protection scheme based on parasitic inductance between the power source and the Kelvin source of the power module has been implemented. A dc-link decoupling snubber circuit is designed numerically based on a detailed forth-order high-frequency equivalent circuit of a double pulse test circuit. The approach to optimize the snubber circuit, not only for the voltage spike suppression but also for good thermal performance, is proposed. Finally, a hardware prototype with SiC power modules has been built and tested at 60 kW continuous power and 100 kW for 20 seconds at 105 °C ambient temperature and 65 °C inlet coolant temperature.