With the increasing environmental concerns, a paradigm shift towards electric and hybrid electric vehicles is expected. Switched Reluctance Motors (SRMs) have emerged as a viable competitor to other established electrical machines. SRMs are known for their simple construction, robustness, inherent fault tolerant structure and low production and maintenance costs. Moreover, the machine has gained interest due to the absence of permanent magnets or windings in the rotor structure, which significantly reduces production costs when compared to other electric motors. The SRM, however, present some known drawbacks, such as increased torque ripple and acoustic noise production, as well as a highly nonlinear behaviour. Through the use of adequate control strategies, however, the main challenges of the machine can be overcome. Thus, this paper presents a state-of-the-art review of the advanced control of SRMs, encompassing current regulation strategies, torque control strategies and vibration suppression techniques. First, two-categories of current controllers are reviewed: model-independent and model-based. Next, indirect and direct torque control methods are explored. Then, three approaches to vibration suppression are discussed, namely active cancellation, current profiling and direct instantaneous force control. Lastly, a summary of each topic is presented and suggestions of future research topics are listed.

This article presents a general-purpose full-speed sensorless control scheme for interior permanent magnet synchronous motors (IPMSMs). By applying a quadratic extended back electromotive force (QBEMF) model, the injection-based and model-based position estimations can be combined into a universal sensorless control strategy for the full-speed operation. At low speed, the QBEMF model acts as a self-demodulator that can extract position information from arbitrary high-frequency currents without using digital filters. Therefore, it is suitable for any type of injection signals and can eliminate the adverse effect of filters. When the injection is removed at high speed, the same QBEMF model can still be used for position estimation, thereby solving the conventional transition issue from low-speed to high-speed sensorless control. In consequence, a unified algorithm is designed to achieve arbitrary injection for low-speed sensorless control and seamless transition across full-speed region. The proposed scheme is hence simpler and more effective compared to conventional full-speed sensorless methods. Finally, the feasibility of the proposed estimation algorithm is verified for a 15-kW IPMSM drive.

Switched reluctance motors (SRMs) are promising traction machine candidates for electric vehicle powertrains and industrial driving systems due to their rugged construction and high efficiency. Precise speed and torque control of SRMs require real-time rotor position information from mechanical position sensors. With the advantages of lower costs and position sensor fault-tolerant capability, various position-sensorless control strategies have been developed for SRM drives in the past decades. This article presents a review of the state-of-the-art sensorless control schemes over a wide speed range. Low-speed methods based on high-frequency pulse voltage injection and high-speed methods based on fundamental excitation are summarized to give readers a systematic categorization. An in-depth comparison of major sensorless control algorithms in estimation accuracy, robustness, universality, and parameter sensitivity is presented. Finally, the existing challenges and future trends are discussed.

Model-based state-of-charge (SOC) and state-of- health (SOH) estimation for lithium-ion batteries has been widely applied in electrified vehicles, while the SOC and SOH estimators are highly coupled and nonlinear in conventional techniques. This leads to a bulky design of observer network and complicates the stability analyses. In this paper, a new reduced-decoupling SOC and SOH co-estimation algorithm based on convex optimization is proposed. This scheme estimates the battery SOC from the battery model and does not require the classic coulomb-counting method. Therefore, it can decouple the capacity estimation from the SOC estimator and reduce the strong interaction existing in conventional co-estimation methods. Besides, all state variables can be solved together by one estimator, which is straightforward and avoids the complicated observer network. Owing to the decoupling design, the stability of the proposed method becomes more intuitive and can be always guaranteed according to the convexity analysis without using other stabilizing approaches. In consequence, a weak-interaction and robust co-estimation algorithm of SOC and SOH can be realized by the proposed technique. The experiments on a 5.4 Ah lithium polymer battery are implemented to validate the feasibility of the algorithm.

Relatively high torque ripple limits the further development of the switched reluctance machine, and the application of the ripple suppression method will reduce the efficiency of the system. To simultaneously improve the efficiency and torque ripple of the switched reluctance machine, a new commutation and online optimization strategy is proposed. According to the torque per ampere characteristics of the machine, two rotor position angles are defined, which are the boundaries for the high and low torque per ampere operation modes of the two adjacent phases, respectively, and for different operating modes, specific torque hysteresis control schemes are performed. Furthermore, an objective function is constructed with the efficiency and torque ripple coefficient, and during the operation of the machine, the defined boundary angles are online optimized by the genetic algorithm to maximize the value of the objective function. The effectiveness of the method is verified by detailed simulation and experiment under different operating conditions.

According to the modular power converter, a novel phase current reconstruction method using single dc-link current sensor is proposed for 3-phase switched reluctance machine (SRM), and the control method is implemented with the reconstructed phase current as well. A highly integrated modular power converter is constructed by a 3-phase full bridge and a dual switch module. The phase windings are in star-connection, and the bipolar phase currents are applied. Based on the special operating modes and single PWM signal injection, the dc-link current is decoupled and the phase current in both magnetization and demagnetization regions is reconstructed, which is very critical for the implementation of some advanced methods that require complete period phase current. The conventional control methods of the SRM, such as single-pulse voltage (SPV) and hysteresis current control (HCC) method, are carried out under different operating conditions with both simulation and experiment to verify the effectiveness of the proposed method, and the reconstruction errors and performance influences are detailed analyzed as well.