The 12/14 bearingless switched reluctance motor was designed to restrain the coupling of torque current to suspension system. However, the robustness of the suspension system is reduced due to the time-varying current and displacement stiffness coefficients, thereby hindering its high-reliable application in the on-board flywheel battery for vehicle. A coupling suspension force regulator (CSFR) that consists of a position decoupling suspension force model (PDSFM) and a dynamic coupling observer (DCO) is designed to solve the above-mentioned problem. The time-varying model of the suspension force is established based on the Maxwell stress method and finite element analysis, which is further decomposed into PDSFM and time-varying coupling suspension force component. The PDSFM is used for the feedback model of suspension system to construct a steady suspension system. The DCO is designed based on the PDSFM to capture the time-varying coupling suspension force component as an external disturbance and feed forward compensation to the suspension control system. The time-varying suspension system is effectively transformed into a time-invariant steady suspension system through the effective cooperation of the PDSFM and DCO. The validity of the CSFR is verified through simulations and experiments.

In order to efficiently use energy storage resources while meeting the power grid primary frequency modulation requirements, an adaptive droop coefficient and SOC balance-based primary frequency modulation control strategy for energy storage is proposed. Taking the SOC of energy storage battery as the control quantity, the depth of energy storage output is adaptively adjusted to prevent the saturation or exhaustion of energy storage SOC. The balanced control strategy is introduced to realize the rational utilization of resources and the fast balance of SOC in the process of primary frequency modulation of energy storage battery under different charge states. Then, four evaluation indexes are proposed to evaluate the effect of primary frequency modulation and SOC maintenance. Taking a regional power grid as an example, a simulation analysis is carried out under step load disturbance and continuous load disturbance. According to the simulation results, the proposed control strategy is effective in power system frequency regulation and battery SOC maintenance.

This article is committed to the establishment of an integral-based high-order sliding mode (iHOSM) controller for one category of nonlinear systems when confronted with perturbations with unknown magnitudes. A striking characteristic is that an integral dynamics is deftly constructed and then incorporated into the original sliding mode system to dispose of the perturbations of unknown magnitudes. On account of the new sliding mode dynamics, we explicitly introduce a systematic design protocol to dexterously design a new iHOSM controller. This is fulfilled through amending the technique of adding a power integrator. The theoretical justification has been guaranteed by the rigorous Lyapunov analysis. The investigations of two elucidative examples are provided to validate the validity and feasibility of the designed methodology.

The suspension system of the 12/14 bearingless switched reluctance motor (BSRM) exhibits inherent time-varying characteristics owing to the salient pole structure of its rotor. However, existing control strategies tend to overlook these timevarying characteristics, resulting in reduced suspension performances, including accuracy and resistance to interference. In response, this study explores a control strategy for addressing the time-varying nature of the suspension system. The timevarying characteristics of the suspension system are initially revealed through finite element analysis and mathematical model representation. Subsequently, a double closed-loop control system for suspension force is designed, including a time-invariant suspension force model (TISFM) and a data driven fuzzy sliding mode observer (DDFSMO). The TISFM is used to conduct a timeinvariant direct suspension force control system, whereas the DDFSMO is designed on the basis of the TISFM to compensate for the error between the TISFM and complete suspension force model (CSFM). The time-varying suspension control system is successfully converted into a time-invariant one by the combined action of the TISFM and DDFSMO. Finally, the validity of the proposed control strategy for time-varying suspension system is validated.

A hybrid double stator bearingless switched reluctance motor with advantages of high suspension output, small loss and weak coupling is presented. This motor can realise electric/power generation and radial two‐degree‐of‐freedom suspension. The biased magnetic field for producing radial force is provided by a permanent magnet, which reduces system power consumption. Self‐decoupling is realised between a torque system and suspension system according to the mechanical structure design. Furthermore, the radial force is approximately constant when the suspension current is constant, thereby improving the controllability of the system. The operation principle is introduced and the electromagnetic characteristics are analysed through the time‐stepping finite element method. This analysis verifies the effectiveness of the theoretical analysis.

This study investigates an outer rotor bearingless flywheel motor for flywheel batteries in vehicle that exhibits the advantages of high integration and low loss due to outer rotor direct‐drive and bearingless technologies. A hybrid excitation outer rotor bearingless flywheel motor with four‐degrees‐of‐freedom radial suspension and permanent magnet bias is also proposed, further improving the advantages of high integration and low loss. In addition, suspension force density is ameliorated and suspension–torque coupling is reduced through structure design. To verify the aforementioned advantages of hybrid excitation outer rotor bearingless flywheel motor, its working principles are introduced and its electromagnetic characteristics are analyzed using the finite element method. Comparisons with 12/8 ORBFM are also conducted by focusing on suspension loss and suspension force density.