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The increasing emissions created by the large-scaled number of automobiles around the world pose severe threats to modern life by causing global warming issues and deteriorating air quality. These serious issues stimulate the essential demand for cleaner, safer, and more efficient vehicles, such as battery electric vehicles (BEVs). Unlike other studies on the charging technologies of BEVs, this paper gives a comprehensive state-of-the-art review on the charging technologies available for BEVs: wired charging and wireless charging technologies. First, the wired charging technologies are systematically classified into AC charging (indirect charging) and DC charging (direct charging) methods based on how the BEVs batteries are fed from the grid. Next, the configurations and commonly used topologies of wireless charging technologies for BEVs are thoroughly discussed. The leading institutes/companies driving advancements in both technologies are also acknowledged. Finally, this paper extensively highlights the recent and future research trends along with the industrial applications.

This paper presents an improved continuous control set model predictive control (CCS-MPC) scheme using a fuzzy logic approach (FLA) for three-phase constant voltage constant frequency (CVCF) inverters with an output LC filter. The proposed method can enhance the output voltage quality by using an optimal predictive control law (OPCL). Additionally, the proposed method corrects the input voltage commands through the FLA-based online gain tuning aiming to satisfy the hardware constraint. Thus, the proposed FLA-based CCS-MPC can guarantee an acceptable output voltage with a faster transient response, smaller steady-state error (SSE), and lower total harmonic distortion (THD). Moreover, a Kalman filter-based load current observer is used to significantly improve the reliability and robustness. Comparative experimental studies with another CCS-MPC method are conducted on a prototype three-phase CVCF inverter using TI TMS320F28335 DSP to validate the improved performance under the step-changes of linear/unbalanced/nonlinear loads with uncertain parameters.

This paper proposes a simple $1^{\mathrm {st}}$ -order disturbance observer (DO)-based optimal control (DOBOC) strategy for surface-mounted permanent magnet synchronous motor (SPMSM) drives. A detailed comparative analysis of three reduced-order (i.e., $1^{\mathrm {st}}$ , $2^{\mathrm {nd}}$ , and $3^{\mathrm {rd}}$ ) DOs has been presented in terms of structural complexity along with transient and steady-state performances. A simple $1^{\mathrm {st}}$ -order DOBOC is proposed with a considerably simple and easy gain tuning procedure without any complex equation and time-consuming weighting matrices selection while ensuring a competitive control performance. Also, the stability of three DOBOCs is proven using the Lyapunov function, which has not been carried out in the previous studies. Furthermore, this paper provides a detailed procedure to systematically select the controller and observer gains of three reduced-order (i.e., $1^{\mathrm {st}}$ , $2^{\mathrm {nd}}$ , and $3^{\mathrm {rd}}$ ) DOBOC by experiment. Comparative experiments are performed to confirm the feasibility of the proposed $1^{\mathrm {st}}$ -order DOBOC using a prototype SPMSM test-bed with a TI TMS320F28335 DSP. Finally, verification results and comparative table are presented to compare the speed tracking performance (e.g., transient response, undershoot (US), steady-state error (SSE), and robustness to load torque disturbances) of three reduced-order DOBOC methods under speed and load torque step-changes.

This paper proposes a theoretical and experimental implementation of an advanced sliding mode control (SMC) for a three-phase voltage source inverter (VSI) to achieve robustness against the unknown uncertainties of an LC filter. The significant contributions of the proposed SMC are summarized as considerations for the matched and mismatched uncertainties of the LC filter, more relaxed norm-bounds, dynamic characterization of sliding surface, and unique stability analysis. Unlike the conventional SMC techniques with matched uncertainties, the mismatched uncertainties in the state matrix are taken for the design of the proposed SMC. Also, the relaxed norm-bound designed for matched and mismatched uncertainties allows a wide range of variations in the values of LC filter. The voltage tracking errors are significantly reduced and the total harmonic distortions (THDs) are highly suppressed by characterizing the sliding surface in terms of flexible linear matrix inequalities (LMIs). Next, the stability analysis and reachability conditions are given using the Lyapunov criterion. The authenticity of the proposed SMC method is proved by TMS320LF28335 DSP based experimental results with a prototype 1-kVA test-bed. The comparative experimental results and analysis for the proposed SMC scheme, the conventional SMC scheme, and the conventional PI-PI control scheme are presented under the load step change, unbalanced load, and non-linear load step change with the parameter uncertainties to demonstrate the excellent performance of the proposed controller such as fast transient response, small steady-state error, and low THD.

This paper proposes an improved torque ripple minimization (TRM) method using model-based loss minimization (LM) control to reduce the torque ripples and enhance the efficiency for surface-mounted permanent magnet synchronous motor (SPMSM) drives. The conventional SPMSM drives usually achieve the maximum torque per ampere (MTPA) control by applying the zero d-axis current (ZDC) and ignore an actual core loss resistance in the controller design. Unlike the conventional MTPA method, the proposed TRM selects the appropriate d-axis current value by making the derivative of the electromagnetic torque equal to zero in the SPMSM drives. Consequently, the proposed method can improve the torque ripples and efficiency compared to the conventional MTPA. Using the proportional-integral (PI) controllers, comparative experimental verifications between the proposed model-based TRM, the conventional model-based MTPA, and the conventional model-based LM are performed through a prototype SPMSM drive with a TI TMS320F28335 digital signal processor (DSP).

This paper proposes a nonlinear disturbance observer (NDO)-based sliding mode speed controller (SMSC) to guarantee the superior control performance in terms of robustness, fast transient response, and small steady-state error for a surface-mounted permanent magnet synchronous motor (SPMSM) drive. Generally, the control performance of the SPMSM drives can be degraded by disturbances, so an NDO with a proper disturbance rejection capability is proposed to appropriately improve the tracking performance of the SMSC designed for the SPMSM drives. Unlike the linear disturbance observers (LDOs), the proposed NDO can efficiently estimate the lumped disturbance such as uncertainties parameters and unmodeled dynamics by using the nonlinear design function. The proposed NDO rejects the complex disturbances as well as self-regulates the observer gains to increase the convergence rate. The feasibility of the proposed NDO-based SMSC is verified by using a MATLAB/Simulink software program and a prototype SPMSM drive system with a TI TMS320F28335 digital signal processor (DSP). The comparative results with a conventional LDO-based SMSC are analyzed under load torque disturbances and model uncertainties to prove the excellent performance of the proposed NDO-based SMSC.

This paper designs an adaptive sliding mode speed controller (ASMSC) that can compensate for parameter uncertainty of an interior permanent magnet synchronous motor (IPMSM) drive. Unlike the previous control systems, the proposed ASMSC guarantees a precise speed tracking capability in the presence of severe parameter variations without accurate knowledge on the motor parameter values and uncertainty bounds. In particular, the proposed adaptive switching gain tuning (ASGT) term can effectively solve the excessive input energy consumption problem due to an unnecessarily overestimated switching gain. Next, the convergence and stability analysis are proven through a Lyapunov function. The feasibility of the proposed approach is verified via experimental results using a prototype IPMSM test bed with a TI TMS320F28335 digital signal processor. In this paper, the proposed SMSC is investigated with two control terms: without an ASGT term and with an ASGT term. In addition, the conventional proportional-integral speed controller and conventional linear matrix inequalities based sliding mode speed controller are chosen for the performance comparison. Finally, the proposed ASMSC can assure more robust and faster speed performances against the parameter uncertainty under three dynamic load conditions.

This paper proposes a simplified near optimal control (NOC) scheme to reject the disturbances of interior permanent magnet synchronous motor (IPMSM) drives by minimizing the complex calculations in the Taylor series method required for solving the state-dependent Riccati equation (SDRE). Since the speed tracking performance of an IPMSM can be significantly degraded in the presence of the disturbances owing to the practical factors (e.g., external load torque, parameter uncertainties, and so on), an SDRE-based near optimal disturbance observer (NODO) is designed to accurately estimate and reject the disturbances associated with the speed and current in the feedforward control. The state-dependent coefficient matrices of the IPMSM are rearranged in the controller and observer to minimize the complex offline calculations of the Taylor series method used to solve the SDRE. By significantly simplifying the calculations, the proposed SDRE-based NOC scheme can be efficiently applied to the IPMSM drives. To verify the precise and robust control performance of the proposed NODO-based near optimal speed controller, experiments are conducted via a prototype IPMSM drive system with a TI-TMS320F28335 DSP under different disturbances. Finally, the comparative experimental results with the conventional NOC are presented under load change and wide speed range conditions.

This paper proposes an improved model predictive control (MPC) scheme with a robust prediction and stability-constrained finite states for three-phase voltage source inverters (3Φ-VSIs) with an LC filter. In this paper, the stability-constrained finite states are selected via the asymptotic stability conditions as a key factor to reduce the total harmonic distortions (THDs) and steady-state errors. Meanwhile, the Kalman filter-based observers improve the overall robustness against model mismatches and noises via a robust prediction. To select the stabilized finite states, the stability conditions are derived by the equivalent feedback-gains and constrained in the exhausting search of the proposed finite-set (FS) MPC. Unlike conventional FS-MPC methods, three control targets (i.e., robustness, stability, and optimality) are simultaneously achieved as the new contributions to remarkably enhance the voltage control performance of the 3Φ-VSI, which are also the challenge of the conventional control methods. To verify the superiority of the proposed FS-MPC, comparative studies are conducted on a prototype three-wire 3Φ-VSI system with a TI TMS320F28335 DSP under practical conditions (i.e., parameter mismatches, linear/nonlinear-load step-changes). The experimental results confirm that the performance of the proposed FS-MPC has been significantly improved in terms of lower THDs, smaller steady-state errors, faster dynamic response, and more robustness under critical system changes as compared with the conventional FS-MPC.

This paper proposes a robust high-order disturbance observer (HODO) for the state-dependent Riccati equation (SDRE)-based suboptimal speed controller of an interior permanent magnet synchronous motor (IPMSM) drive. The conventional disturbance observers (DOs) cannot accurately estimate the fast time-varying disturbances of an IPMSM during the transient-state because the disturbances are assumed to change slowly, so the inaccurately estimated disturbances lead to conservative robust control. Unlike the conventional DOs, the proposed HODO guarantees the fast convergence of the estimated error for an IPMSM drive by accurately estimating the fast time-varying disturbances and their all high-order derivatives. Also, it is specifically applicable to the SDRE based suboptimal speed controller which cannot completely eliminate the steady-state error in the presence of mismatched disturbances and uncertainties. Finally, the simulation results via a MATLAB/Simulink package and the experimental results via a prototype IPMSM test-bed having TI TMS320F28335 DSP are presented to verify the faster dynamic response, smaller steady-state error, and more robust response of the SDRE speed controller with the proposed HODO compared with the conventional 1st-order DO, conventional generalized proportional integral observer (GPIO), and conventional SDRE observer.