Conventional pulse-frequency modulation (PFM) requires an excessively high switching frequency to achieve low voltage gain in half-bridge (HB) LLC resonant converters, which may exceed the practical limits of power devices and digital controllers. To address this issue, a sigma–delta-based hybrid modulation strategy is proposed to achieve a wide low-gain range within a constrained switching-frequency range while reducing the peak resonant current. For voltage gains ranging from 0.32 to 0.40, variable-duty Mode A shortens the switch conduction interval and reshapes the resonant trajectory, thereby reducing the energy transferred per switching cycle while maintaining operation near the resonant frequency. For voltage gains below 0.32, a sigma–delta modulator is used to allocate pulse units between Mode A and block mode, enabling continuous regulation of the average voltage gain. By distributing the transferred energy more uniformly over time, the proposed strategy alleviates the energy concentration associated with conventional burst-mode control and consequently reduces the peak resonant current. Compared with conventional PFM, which requires a switching-frequency range of 150–332 kHz, the proposed strategy achieves continuous voltage-gain regulation from 0.25 to 0.40 within a constrained switching-frequency range of 31–102 kHz, while achieving a peak efficiency of 95.7%, comparable to that obtained using PFM.
In-wheel motors (IWMs) and suspension systems are usually arranged as independent subsystems in electric vehicles, and conventional in-wheel motors provide only rotational driving output. This paper proposes a dual-vector in-wheel motor (DVIWM) that integrates wheel driving and suspension actuation within a single topology. The proposed architecture organizes the common and differential components of the two stator torques into drive- and suspension-related coordinates associated with distinct physical output paths. Based on this topology, a dual-vector control strategy, an integrated motor–suspension simulation model, and a proof-of-concept prototype are developed. Simulation and experimental results verify, at the principle level, the feasibility of the proposed topology and control strategy. The DVIWM therefore extends the functionality of conventional in-wheel motors and establishes a topology-level basis for integrated drive–suspension research.
This article investigates the effects of magnetic field modulation and non-uniform stator tooth sampling on the electromagnetic force and vibration in the flux-concentrated phase-group centralized winding permanent magnet synchronous machines (FPCW-PMSM). First, the structure and operating principle of FPCW-PMSM are analyzed, and the advantages of this type of machine are clarified. Then, the magnetic field modulation and electromagnetic force modulation effects of the machine are analyzed, and the effects of uniform and non-uniform stator-tooth sampling on force modulation and vibration are compared in detail. The results show that non-uniform stator-tooth sampling can modulate high-order force harmonics into multiple low-order force harmonics, exerting multifaceted effects on vibration. Therefore, this effect cannot be neglected in the accurate prediction and suppression of vibration. Finally, a prototype is manufactured and tested, validating the theoretical analysis.
Battery electric vehicles increasingly adopt dual-motor powertrains to improve efficiency and traction, but disconnect clutches introduce driving mode shifting decisions and synchronization transients that affect both energy consumption and driveability. This paper proposes a soft actor–critic-based energy management system (SAC-EMS) that jointly optimizes front–rear torque split and clutch toggling for a service van under variable payloads and drive cycles. The training environment embeds clutch synchronization dynamics, including speed matching, time- and power-dependent spin-up/spin-down, engagement logic, and transient energy, enabling the policy to learn feasibility and transition costs while penalizing excessive clutch toggling. The learned strategy achieves energy consumption within -0.2% and +1.0% of the dynamic programming benchmark on average under empty and fully laden conditions, respectively, while reducing clutch toggling by about 75% relative to the look-up table-based baseline. Evaluating both metrics jointly is necessary, as the dynamic programming benchmark trades a small energy margin for superior clutch engagement quality, and energy consumption alone does not fully characterize the efficiency-driveability trade-off. Since the SAC-EMS issues discrete torque split commands that can yield abrupt torque transitions, an engagement-aware torque smoothing layer that preserves total torque delivery while rate-limiting updates and ramping the front axle share is incorporated and evaluated in a high-fidelity, realtime driving simulator. Across simulator tests, the layer reduces the longitudinal jerk RMS by 11.3% and peak jerk by 42.5%.
High-power pulsed loads in more electric aircraft may cause severe dc-bus voltage deviations and place stringent requirements on the transient power-sharing capability of hybrid energy storage systems. This article proposes a quasi-first-order frequency-splitting phase compensator for a battery–supercapacitor HESS. Unlike the ideal frequency-splitting assumption that neglects the dynamics of the subsequent current-control loops, the proposed formulation explicitly incorporates the non-ideal reference-to-current dynamics into the power-allocation process. A realizable first-order phase compensation element is synthesized at the interface between the LPF/HPF power-allocation stage and the existing branch current-control loops, with its parameters constrained by the designated HESS frequency-splitting frequency and the identified reduced-order branch dynamics. The proposed method compensates the additional current-channel phase lag around the splitting region while retaining the original dual-loop control architecture. Closed-loop eigenvalue and source/load impedance-interaction analyses verify that the proposed compensation does not compromise system stability. Simulation and experimental results demonstrate reduced dc-bus voltage deviation and substantially faster transient recovery under pulsed-load disturbances.
