The substantial rise in the demand for electric vehicles (EVs) has emphasized an environment-friendly and intelligent design for speed control strategies. In this paper, a Mamdani fuzzy logic controller (MFLC) was proposed to vigorously control the speed of EVs at discrete levels. MFLC member functions (MFs) are tuned for EVs operating at three different speed modes (40, 60, and 80 km/h). The proposed speed controller operation for the speed tracking of EVs was designed and tested in MATLAB (Simulink) environment. The proposed speed controller validated a remarkable improvement in dynamic speed control compared with existing P-I, FLC, Fuzzy FOPID (ACO), Fuzzy FOPID (GA), and Fuzzy FOPID (PSO) controllers. Its stability under a user-defined drive pattern is also observed. In this proposed work, the speed controller highlights the better tracking of user-defined speed response compared to the conventional aforementioned controllers. Moreover, the speed tracking of the designed model was tested for robustness against speed transients at predefined time instants, respectively. The comparison suggests that the MFLC model removes overshoot and significantly reduces the steady-state time.

The speed control of induction machines for multiple-speed handling is critical. When the vector control method is applied to induction machines, it has a significant impact on speed utilization. This strategy of operating the machine at a fixed predefined speed mode presents better results for electric vehicles. An effective model for a speed control loop is proposed in this paper, using a fixed-mode proportional integral (FM-PI) controller based on an upper and lower limit torque limiter. The power supply is fed using a lithium-ion battery with an inverter-fed mechanism. Moreover, the proposed model is validated using simulations with user-defined speed modes (40, 60, and 80 km/h). These speed modes, with different torque commands, have been considered for advanced modeling. In this model, torque is developed via a closed-loop control operation to attain the required speed assigned by the user. The sensors are used to collect data, and a multiple regression algorithm analyzes the dataset to predict input parameters (voltage (V_ab), phase current (I), and torque (T)) required to achieve the desired speed mode. The efficiency of the proposed model is compared with induction motors bearing the same rating for the loaded and unloaded speed test. Effective machine parameter control is achieved by reaching the desired performance levels of 94.37% and 78.30% in a shorter time for the loaded and unloaded modes. A speed response comparison of the FOPID, KW-WOA-PID, SVR-PI, and FM-PI controller model simulation results indicates that the FM-PI speed controller guarantees better performance and displays an improvement in rising time and settling time, compared to other controllers. The implementation of different driving scenarios proves the model’s effectiveness for robust speed applications.

The parasitic currents issue arises in induction machines operating at higher frequencies. The parasitic current flow is the main cause of premature degradation of winding insulation deterioration and bearing damage. The effect of electromagnetic interference (EMI) requires investigating an equivalent per-phase model of an induction motor (IM) at higher frequencies. The per-phase induction motor mathematical model of the IM drive for common mode (CM) configuration is developed to perform high-frequency analysis for drive operation. The high-frequency per-phase induction motor model MATLAB (2021b) is developed to generate the transfer function of IM drive and generate bode plots for both CM and differential mode (DM) impedance configuration at higher frequency. Initially, the IM typical frequency response without considerations of stray and parasitic effects is presented for normal behavior of the IM. In order to verify the simulated impedance parameters of 0.3 kW and 38 kW IMs with stray and parasitic components, a high-frequency response for magnitude and phase response is generated and compared to analyze per-phase induction motor model performance before and after resonance frequencies. The comparison of CM and DM bode plots validates the dominance of inductance and parasitic capacitance before and after the occurrence of resonance frequency, respectively. The analysis suggests that 38 kW IM resonance occurs in MHz range which exhibits much better performance compared to the 0.3 kW IM model.

The parasitic currents issue arises at high frequency operation of induction motor. The flow of parasitic currents is the main cause of premature deterioration of winding insulation and damage to the ball bearing. In order to comprehend the effect of electromagnetic interference (EMI) an equivalent per-phase model of an induction motor should be investigated at higher frequencies. The per-phase induction motor mathematical model of induction motor drive for common mode (CM) configuration is developed to perform high frequency analysis for drive operation. The high frequency per phase induction motor model MATLAB model is developed to generate the transfer function of IM and generate bode plots for CM and differential mode (DM) impedance configuration for high frequency analysis. The induction motor typical frequency response without considerations of stray and parasitic effects is presented for normal behavior of IM. In order to verify the simulated impedance parameters of 0.3 kW and 38kW induction motor with stray and parasitic components. High frequency response for magnitude and phase response is generated and compared to analyze per phase induction motor model performance before and after resonance frequencies. The comparison of CM and DM bode plots validates the dominance of inductance and parasitic capacitance before and after the occurrence of resonance frequency respectively.

Power transient faults on high voltage lines mainly occur at high frequencies. These high frequency transients affect the predicted life and efficiency of equipment. Generally, Real time testing of transformers is performed to obtain digital data. FFT analysis is applied to see the incorporation of frequencies. Models are developed at different frequencies with respect to tested specimen. Frequency response analysis is also used for the diagnosis. The major case of study is; to define the frequencies incorporation based on transformer resonating core of a particular transformer. Under the influence of high voltage (HV) transient, change in impedance of the transformer has been observed by transfer function method; this change in impedances gradually degrades the life of a core. In this research, the idea is to define the frequencies i.e. single or dual core resonant frequencies dominations with respect to different rating of the transformers, which are helpful for scholars in a generic way to perform characteristics analysis and modeling a design. Firstly, transformers of different ratings i.e. 100, 50 and 30 kVA are investigated in the published researches. Secondly, an experiment is performed on 25 kVA transformer, then a concept has been developed which defines the single resonance behavior practically occurs at equal or less than 50 kVA; above 50 kVA i.e. 100 kVA transformer core resonates twice. Results have shown that this concept, defines the core deviating frequencies with respect to the ratings.

Frequencies Dominations for Different Rating of Distribution Transformer under Transients