A dynamic interleaving method is proposed in this paper for the asymmetric dual three-phase permanent magnet synchronous machine drive system to reduce the dc-link current ripple. The proposed method dynamically varies the phase shift angle (interleaving angle) between the pulse width modulation (PWM) carriers of the two three-phase subsystems. The proposed method reduces the dc-link current ripple significantly compared to the no interleaving and constant interleaving methods. Reduction in the dc-link current ripple reduces the dc-link capacitor requirement and substantially increases the inverters' volumetric power density. Simulation and experimental results are provided to validate the performance of the proposed method.

A regenerative inverter output dV/dt filter topology is proposed for a Wide-bandgap (WBG) device-based motor drive system. This work eliminates the requirement of a passive resistor in an LCR filter topology with a GaN-based fullbridge converter. The proposed unit mimics the operation of the passive resistor by recycling the energy of the filter path. The proposed active filter only processes the high-frequency power, so the current ratings of the devices in the regenerative filter are significantly lower compared to the main converter's switches. This regenerative active resistor allows the use of a lower filter inductor in the series path, reducing the overall filter size. As a result, the proposed regenerative ultra-low loss dV/dt filter minimizes the stress on the motor insulation and improves the motor drive system's efficiency and power density. Detailed MATLAB/Simulink-based simulation results are provided to validate the performance of the proposed filter topology. An experimental double pulse test (DPT) results have been performed to validate the operation of the proposed concept.

The bifilar wound switched reluctance motor (BSRM) has transformer-like windings on the stator known as primary and secondary windings and has a unique power converter known asthe bifilar converter. In this study, an optimized BSRM winding topology along with the lossless snubber for the converter is proposed. The topology investigates the uneven number of turns on the primary and secondary windings of the BSRM while taking into account the converter switch voltage spike, secondary winding current density, and demagnetization time. A lossless snubber circuit is introduced to suppress the switch voltage spike caused by the leakage inductance while preserving the efficiency of the bifilar converter. Another motivation for this research is that the bifilar converter uses fewer switches and diodes than the asymmetric half-bridge converter, which is promising to reduce costs and improve drive system efficiency. The BSRM drive system is designed and compared with the same size conventionally wound switched reluctance motor (CSRM) drive system in terms of physical structure, and efficiency using a multi-physics circuit and finite element analysis (FEA) simulation tools. The operating principle of the bifilar converter has been thoroughly examined, further, the physical setup of the BSRM drive system is tested, and the experimental results are provided

Cost optimization is a major concern for autonomous electric vehicles. This optimization problem becomes complicated if a group of vehicles as a fleet move along the road. Optimization based on the leading vehicle to generate the fleet speed profile might not guarantee the overall minimum cost of the fleet. In this paper, an optimization algorithm for a fleet of autonomous electric vehicles is proposed using the total cost of the fleet to generate the optimum speed profile so that the overall cost of the fleet is reduced. Maintaining a safe distance with the adjacent vehicles and safe lane changing on a multilane road depends on the accuracy of decision making based on the data coming from the embedded sensors in the autonomous vehicle. Both of those two cases can be satisfied easily if the vehicles are moving as a group on the same fleet speed where the individual speed of each vehicle can be adjusted based on the relative distance with the leading vehicle. An artificial intelligence (AI) based realistic autonomous electric vehicle modeling considering all the route conditions is provided in this paper, and optimization is done for a fleet of two vehicles where the physical models of the vehicles are different from each other. The proposed optimization algorithm shows a reduction of the total cost for the fleet compared to the optimization done based on only the leading vehicle's cost.

This paper focuses on the design of a bidirectional dual active bridge (DAB) DC/DC converter that utilizes Gallium Nitride (GaN) switches as active components. In the existing literature, MOSFET-based DAB for active cell balancing is available, but GaN-based DAB converter for active cell balancing is still new. The proposed modular isolated GaN-based DAB converter is designed as an individual module of active cell balancing for behind-the-meter storage (BTMS) applications, targeting high-power charging stations. Modular isolated converters are connected to each cell (low voltage bus), and each cell is connected in series to build up a battery module. According to the reference current command of supervisory control, each DAB converter can transfer power back and forth through the high voltage (HV) bus to balance the State of Charge (SoC) between the cells. Each module DAB converter is designed at a 50W power rating. Switch power and transformer losses are analyzed for different switching frequencies, showing the optimum switching frequency for minimum losses. Furthermore, the procedure to select the required gate driver and the PCB layout optimization are discussed. Finally, the DAB performance analysis of GaN-based DAB and Si-based DAB is provided for a battery module operating with a LiFeMnPO 4 prismatic cell with 3.2V 20Ah rated values.

Battery management systems (BMS) are essential for a battery pack's safe operation and longevity. This paper presents an active balancing method-based BMS for different cell chemistry structures to be used in behind-the-meter storage (BTMS) applications. The proposed system utilizes modular isolated dual active bridge (DAB) DC/DC converters to actively balance the battery pack through a low voltage (LV) bus. A supervisory controller monitors all the cell voltage, current, and state of charge (SOC) values. Based on the estimation of the SOCs, reference currents for the DAB converters are generated by the supervisory controller. Detailed modeling and the control approach of the modular DAB converters are presented in the paper. Moreover, the control strategy of the supervisory control is also analyzed. The proposed method and structure can be extended to any combination of the number of cells to design the battery pack. Simulation results are provided for a system consisting of three cells in parallel to form a cell block and three cell blocks in series to form the battery module. Experimental results are provided for three modular DAB converters operating with a LiFeMnPO4 prismatic cell with 3.2V, 20Ah rated values.

This article proposes a two-layer overlapping winding–based three-phase wireless vehicle charging system with a coil span of 180°. This coil structure offers higher coupling and balance inductance matrices between the transmitter and receiver and improves system efficiency. The system performance improvement has been validated through detailed analysis and simulation results and compared with the benchmark for the same electrical parameters, air gap, and coil volume. Finite element analysis–based simulation results were presented for a 7.7-kW wireless power transfer (WPT) over a 200-mm air gap. An experimental prototype of the proposed system is developed operating at the resonant frequency of 86 kHz with a 200-mm air gap between the coils to validate the design. Both the simulation and experimental results showed a significant increase in efficiency and coupling compared to the conventional WPT systems.

This work presents a detailed finite element analysis (FEA) based design and optimization approach for SiC dual-three phase integrated permanent magnet synchronous motor drive system. ANSYS Q3D based commutation loop inductance (CLI) minimization through strategic high frequency decoupling capacitor (HFDC) placement, module interconnect design, and PCB design is proposed in this work. In addition, FEA based integrated planar inductor design method is proposed to achieve the desired performance of the output dv/dt filter. The CLI minimization approach is validated through a double pulse test (DPT). Finally, a motor drive co-simulation approach is presented in the paper considering the systems parasitics and non-idealities.

The design aspects, challenges, and benefits of a SiC-based integrated switched reluctance machine (SRM) drive system are demonstrated in this work. The impact of noise, vibration, and harshness (NVH), thermal, motor-end voltage oscillation and overshoot, and mechanical design aspects are explored and analyzed for both the non-integrated and integrated SRM drive system. Integration of the inverter and the motor can increase low-frequency acoustic noise in the integrated drive system. Integrated cooling systems for both motor and inverter introduce new challenges from the mechanical and thermal design point of view. However, an integrated drive system eliminates the issue of voltage overshoot and oscillation due to the long cable between the motor and the inverter for a non-integrated drive system. Both simulation and experimental results are provided to validate the analysis.

A dominant spatial airgap force order-based reference current profiling scheme is proposed in this work for noise, vibration and harshness (NVH) mitigation in Switched Reluctance Machines (SRM). The current profile optimization strategy is coupled with a fast vibration prediction method. Extensive simulations and experimentations are done on an 18 slot/12 pole SRM to verify the proposed strategy. Worst case noise scenario for the 18 slot/12 pole SRM is determined through experimental run-up test under constant torque condition. The proposed current shaping strategy is applied at the operating point experiencing worst case noise and significant NVH reduction is obtained through simulation and experimentation. Experimental results show a peak noise reduction of 14.24 dBA compared to a conventional square wave based current reference.

An interleaved fixed switching frequency predictive current control method is proposed to reduce the amount of dc link capacitors for switched reluctance motor (SRM) drives. The proposed interleaving technique ensures a reduction of the dominant harmonic content of the dc-link current, concentrated around twice switching frequency $(2f_{sw})$, which in turn reduces the dc-link capacitor requirement significantly. Therefore, it also enables lowering the switching frequency of the converter for achieving higher system efficiency while maintaining significantly low dc-link capacitor requirement. The proposed method does not require phase current shaping which ensures no additional current stress on the inverter switches and the motor phase windings. Furthermore, no additional hardware requirement makes this approach very cost effective. Simulation results are provided to support the effectiveness of the proposed control technique.

In this work, the impact of a current profiling technique, aimed at noise, vibration and harshness (NVH) mitigation, on a Switched Reluctance Machine (SRM) and the associated dynamometer structure is studied through detailed modeling and experimental validation. The dynamometer structure used in this study mimics real-world accessories as the gearbox, crankshaft and other parts that might have physical connection to the SRM drive in an automotive application scenario. Analysis shows that current profiling while reducing vibration on the SRM can cause significant vibration increment on the associated dynamometer structure. Acoustic noise increment as high as 14 dBA is seen at frequencies associated with the dynamometer structure while obtaining 6.54 dBA reduction at dominating SRM frequency for a current profile. This validates the necessity of considering SRM drive and its’ accessories, to reflect real-world application scenario and to avoid unwanted noise increment, during validation of any current profiling technique.

This study proposes a flexible, compact, efficient, and cost effective electric vehicle-to-electric vehicle charge sharing solution that will lead to faster and wider customer adoption of electric vehicles (EVs) as an alternative to current grid-to-vehicle charging methodologies. The energy will be transferred between EVs using a bidirectional dc-dc converter in a conductive way, which can take place at parking lots of workplaces, campuses, or residential premises and highways. The proposed design provides compact infrastructure, wide input and output voltage ranges with bidirectional buck-boost operation, and fast power transfer compared to Level 2 charging stations. A complete design comparison between Si and SiC based converters has been carried out based on the available power modules and magnetic cores. The comparison demonstrates the effect of switching frequency and switch selection on the size of passive components, the converter efficiency, and the power density of the converter. The developed study evaluated three different bidirectional dc-dc converter topologies and validated the developed prototype with experimental results.

A model reference adaptive current control (MRAC) method for the dual three phase permanent magnet synchronous machine is proposed in this paper. Although predictive current control shows an excellent transient performance compared to the PI controller method, its steady state performance can deteriorate if there is any error in estimating the machine’s parameters. The proposed MRAC method estimates the disturbance due to the error in the parameters and feeds the error forward to the controller to eliminate it. While maintaining the predictive control’s good transient performance, the proposed method can also improve the predictive control’s steady state performance under parameter variation. As a result, it can be easily implemented along with the existing predictive current control. Theoretical background and the stability of the proposed system is derived. Simulation results are provided to validate the performance of the proposed method.

In this paper, reliability models for Switched Reluctance Machine (SRM) are presented to estimate Mean Time to Failure (MTTF) when operated during normal and fault conditions. Markov state transition diagrams and reliability models are used to estimate the reliability of the machine following different fault occurrence levels. The variation of phase currents, output torque, and magnetic force acting on stator and rotor poles due to fault in the machine are recorded for failure rate estimation from electromagnetic simulations. The failure rate of each part in SRM is calculated using empirical-based models and is combined to calculate the machine's reliability and MTTF. A 32 kW, 18 slot/12 pole SRM is considered to perform state assessment and calculate the failure rate of parts in SRM. For validation of the presented results, reliability prediction from phase currents and torque obtained from the experiment is compared with simulations.

In this work, A novel phase collaborative, dynamic interleaving technique for SRM drive is proposed to achieve phase current sensor-less operation. The proposed method enables a direct reconstruction of phase current from the dc-link current sensor without using any additional observer-based controller or additional high-frequency pulse injection. The proposed dynamic interleaving current control method prevents the mix-up of pulsating current from different phases. Thus, the dc-link current sensor’s peak current measurement requirement is not more than the phase current sensors’ specification. Eliminating the requirement of phase current sensors helps developing a compact sized converter and improves the reliability of the drive operation. Simulation results are provided to support the effectiveness of the proposed control technique.

A Bifilar wound switched reluctance machine (BSRM) with the same physical dimensions and specifications as a conventional SRM is studied. The global response surface optimization method is used to select optimal winding turns on both primary and secondary windings of the BSRM. The BSRM is coupled with a circuit design simulation tool to form Hi-fidelity co-simulation for analyzing the more realistic performance of the motor as well as a converter. The motor and the inverter efficiencies of the designed BSRM in comparison with the conventional SRM are presented.

This article focuses on reducing the battery size requirements of electric busses using battery charging and speed profile optimization. To minimize the energy consumption costs and the battery size, an opportunity charging city bus networks has been investigated. An electric bus architecture, traffic, weather, and road conditions, as well as the driver behaviors, have been modeled to simulate the overall system and predict energy consumption. The optimization algorithm is developed to determine the optimal driving cycle and the charging time on each bus stop. The algorithms are tested on case studies, which verified that the proposed approach reduces the energy consumption and battery size requirements of electric busses.

Switched reluctance machine (SRM) drive requires a large dc-link capacitor due to the low-frequency harmonics in dc-link current, which is generated during the current commutation between phases. Installing a bulky capacitor bank in the drive has a significant impact on the cost and the overall volumetric power density of the drive. This article analyzes the dc-link current ripple in SRM drive and proposes a control algorithm to reduce the dc-link current ripple while maintaining the machine performance. The proposed algorithm extracts the ripple components from the dc-link current using a high-pass filter. The controller ensures ripple energy circulation between the phases and reduces the pulsating energy requirement from the dc supply. The dc-link ripple is suppressed at a wide speed range of operation to enable efficient and reliable drive operation without adding any external hardware system. Simulation and experimental results are provided to prove the effectiveness of the proposed control technique for both steady-state and transient conditions.

Harmonic injection in dc-link current through phase current shaping is a well-known method to reduce the dc-link ripple in Switched Reluctance Machine (SRM) drive system while maintaining the machine performance. However, this method is susceptible to the accuracy of the position and the current sensors. This paper presents an analytical approach to model the effect of sensor errors on the dc-link current ripple in the SRM drive system. At first, inverter current is modeled utilizing the Fourier series representation of both the phase current and the switching function. Then, the expression for the dc-link current is obtained after considering the amplitude and phase contribution coming from the dc-link capacitor and the battery dynamics. Subsequently, position and current sensor errors in the SRM drive system are included in the analytical modeling, and the expressions for the additional harmonic content in the dc-link current ripple are achieved. Finally, the effect of sensor errors is verified using simulation and experimental results.