Radial force F r is the main cause of electromagnetic vibration and noise in motors. In this study, the vibration and noise characteristics of a permanent magnet synchronous motor (PMSM) with consideration of rotor-step skewing are investigated. Firstly, the analytical model of F r considering rotor-step skewing is deduced based on the Maxwell stress tensor method. The influence of rotor-step skewing on F r of the PMSM is then analysed and summarised. Taking a 65 kW PMSM commonly used in electric vehicles as an example, combined with electromagnetic finite element analysis, F r is then evaluated. Secondly, an electromagnetic vibration and noise simulation analysis is conducted based on a multi-physical field joint simulation platform, from which the influence of rotor-step skewing on the vibration and noise is then summarised. Finally, a noise experiment is then carried out. The results obtained from the multi-physical analysis and the tests conducted are presented to validate the precision of the simulation models, and the accuracy of the analytical model of F r. 2 Structure of rotor-step-skewed PMSM 2.1 Structure features of rotor-step-skewed PMSM The rotor-skewing structure has been considered as an effective measure to suppress the electromagnetic vibration noise of PMSMs. The rotor structure with step skewing is shown in Fig. 1b. The rotor is divided into several segments equably in the axial direction, and each segment is shifted sequentially at the same angle in the circumferential direction. 2.2 Specifications of prototype The cross-sectional view of the prototype studied in this paper is shown in Fig. 2. The motor is an 8-pole 48-slot PMSM with a rated power of 65 kW. The specification of which is shown in Table 1.
Abstract:The in-wheel motor has received more attention owing to its simple structure, high transmission efficiency, flexible control, and easy integration design. It is difficult to achieve high performance with conventional motors due to their dimensions and structure. This paper presents a new dual-stator and dual-field-excitation permanent-magnet in-wheel motor (DDPMIM) that is based on the structure of the conventional in-wheel motor and the structure of both the radial and axial magnetic field motor. The finite element analysis (FEA) model of the DDPMIM is established and compared with that of the conventional in-wheel motor. The results show that the DDPMIM achieves a higher output torque at low speeds and that the flux-weakening control strategy is not needed in the full speed range.
Abstract:The key to control the range extender generation system is to improve the efficiency and reduce the emissions of the electric vehicle (EV). In this paper, based on the purpose of efficiency optimization, both engine and generator are matched to get a public high efficiency region, and a partial power following control strategy was presented. The engine speed is constant in the defined power range, so the output power regulation of the range extender is only realized by the adjustment of the torque of the generator. Engine speed and generator torque were decoupled. An improved proportional resonant (PR) controller is adopted to achieve fast output power regulation. In order to ensure the response characteristics of the control system and to improve the robustness, the impacts on system's characteristics and stability caused by PR controller and parameters in the inner-current loop were analyzed via frequency response characteristics. A pre-Tustin with deviation compensation is proposed for PR controller's discretization. A stable and robust power following control method is obtained for the range extender control system. Finally, simulation and experiment of the proposed control strategy illustrated its feasibility and correctness.
This paper proposes a new rotor interturn short circuit (RISC) fault analysis model for the electromechanical property study in synchronous generators. The specific novelty of this model lies in two aspects: 1) It considers that most generators exist static air-gap eccentricity (SAGE), so it analyzes the RISC fault under normal and SAGE, making the model more versatile, and 2) it takes into account not only the short circuit degree but also the short circuit position, consequently it is more universal. By feeding the number of short circuit turns (denotes the short circuit degree), the angle between the two slots where the short circuit takes place (denotes the short circuit position) and the detailed parameters of the generator into the model, the developing tendency of the key magnetic flux density MFD-based parameters can be conveniently predicted. The advantages of the proposed model primarily lie in the universality and the calculation speed. It can quickly evaluate the generator operating conditions. The phase current and the electromagnetic torque (EMT) are selected in this paper as the representatives of the electrical parameter and the mechanical parameter, respectively. 2D finite element analysis (FEA) and experimental studies validate the proposed model.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.