Research on the influence of temperature on the performance of induction motor

Background: : Induction motor occupies a large proportion in various industries, and its number is increasing. Due to the environmental temperature or sealed working environment, heat generation is generally serious. The heat exchange with the outside environment does not take place smoothly and the motor temperature increases. The performance of the induction motors also significantly influenced by the temperature. Therefore, it is necessary to study the influence of temperature on the performance of induction motor. Objective: The influence of temperature on induction motor is analysed. The variation of performance parameters at different temperatures is obtained. Methods: Taking an 11 kW, 1500r/min induction motor as an example, a two-dimensional transient electromagnetic field model was established, and the correctness of the model was verified by experiments. The motor starting performance, various losses and efficiency under different temperatures were calculated. Results : As the stator and rotor resistance increases, the starting current decreases by 11.99% when the internal temperature rises from 25℃ to 150℃. When the internal temperature rises from 25℃ to 150℃, the stator copper loss increases by 32.83%, and the rotor copper loss increases by 28.79%. However, the core loss of the motor increases by 3W. and the motor efficiency decreases by 2.12%. Conclusion: When the temperature is different, the starting torque of the motor is almost unchanged, and the starting current decreases with the increase of temperature. The stator copper loss and rotor copper loss of the motor increase with the increase of temperature, while the core loss is almost unchanged. In addition, the efficiency of the motor gradually decreases with the increase of temperature.

Design and performance improvements of solar based efficient hybrid electric vehicle

Hybrid energy in electric vehicles has been globally accepted as the fossil fuels will be exhausted by the middle or end of 21st century. The hybrid vehicles have emerged as a major source of clean and renewable energy to support the never-ending demand of vehicles. The main idea of the paper is the use of hybrid energy in working of e-rickshaw, which has become the most favorite area of research in automobile industry, recently. The proposed model is powered by lead-acid battery and this battery is charged by either using electric plug or solar panel. In the present study, hardware model has been analyzed e-rickshaw in terms of different parameters like mileage, charging and discharging time of battery, charging current, discharging current from the performance as well as security point of view. The hardware model has been developed with Photovoltaic (PV) module, capacitor bank, and Arduino circuit. Here, a modified e-rickshaw has been developed which has improved vehicle performance as compared to existing conventional e-rickshaw. The mileage has improved from 80 to 120.61 km and starting current has been reduced from 57 to 41 A on full load conditions. This has enhanced the battery life and Arduino circuit was implemented to enhance security features. The proposed model of e-rickshaw has improved vehicle performance as compared to existing conventional e-rickshaw in terms of mileage, starting current, battery life, and security feature of the vehicle.

Starting of induction motor fed with stand-alone DFIG

This paper presents dynamic simulation and control of stand-alone doubly fed induction generator (DFIG) loaded with 3-phase induction motors (IMs). The study reveals that direct on-line starting of large IMs causes a large voltage sag across the generator terminals as the starting current drawn reaches up to 8-9 times the rated load current. Traditionally, this problem has tackled by oversizing of the generator or employment of special starters, under the pretext of mitigating voltage sag. This work explores ways that the starting current can be reduced economically by applying constant V/f control side by side with indirect field-oriented control (FOC) applied on the rotor side converter of the DFIG. This methodology enables starting of larger IMs and mitigation of voltage sag that occurs during the start-up period. Two different rating of IMs loaded with speed-squared mechanical torque are mainly considered. Simulation results of the system behavior under study confirm the capability of the proposed control.

Multistage Mechanical Activation of Multilayer Carbon Nanotubes in Creation of Electric Heaters with Self-Regulating Temperature

The article deals with research related to the issues of nanomodification of elastomers as a basis of electric heaters with self-regulating temperature. The effect of multistage mechanical activation of multilayer carbon nanotubes (MCNTs) with graphite on the uniformity of the temperature field distribution on the surface of nanomodified organosilicon elastomer has been studied. The influence of the stages of mechanical action on the parameters of MCNTs is revealed. It has been ascertained that for the MCNTs/graphite bulk material, which has passed the stage of mechanical activation in the vortex layer apparatus, a more uniform distribution of the temperature field and an increase in temperature to 57.1 °C at the supply voltage of 100 V are typical. The distribution of the temperature field in the centrifugal paddle mixer “WF-20B” for mixing MCNTs with graphite has been investigated. It has been found that there is also a thermal effect in addition to the mechanical action on the MCNTs in the paddle mixer “WF-20B”. The thermal effect is associated with the transfer of the mechanical energy of friction of the binary mixture MCNTs/graphite on the paddle and the walls of the vessel. The multiplicity of the starting current Ip to the nominal In (Ip/In) is 5 for the first sample, 7.5 for the second sample, and 10 for the third sample at the supply voltage of 100 V. The effect of reducing the starting current and stabilizing the temperature indicates the presence of self-regulation, which is expressed in maintaining a certain level of temperature.

A method for calculating the parameters of the sine filter of the frequency converter, taking into account the criterion of starting current limitation and pulse-width modulation frequency

An analysis of the method for ensuring the sinusoidality of the output voltage in power generation systems with self-commutated voltage inverters under the requirements of the international standard IEEE-519 is presented. In a number of programs, especially low-power generation systems, a low-cost solution is needed to provide the sinusoidal waveform of the output voltage with the total harmonic distortion of 5 %. This solution is to use two-level voltage inverters with an output sine LC filter. However, the feature of the sine filter with the frequency converter is that the PWM frequency affects the spectrum of higher harmonics of the output voltage. In addition, there is the starting current of the filter capacitor, which can disable the power switches of the voltage inverter. The developed method for calculating the values of the LC filter with the two-level voltage inverter in the PWM mode is presented meeting the requirements of the international standard IEEE-519, taking into account the modulation frequency and limitation of the starting current of the filter capacitor. To confirm the required quality of the output voltage of the two-level voltage inverter with the sine filter, an appropriate simulation model was created in the Matlab/Simulink computer simulation environment. The oscillograms and harmonic analysis of the input and output voltages of the sine filter, which showed the total harmonic distortion of 1.88 %, are presented. A physical prototype of the investigated system was created on the basis of a 5.5 kW OVEN PChV203-5K5-V frequency converter (Ukraine). Using the SIGLENT SDS1104X-E oscilloscope (China), the real waveform and the results of the harmonic analysis of the sine filter output voltage, confirming the implementation of the necessary sinusoidality criteria, were obtained

Intelligent Starting Current-Based Fault Identification of an Induction Motor Operating under Various Power Quality Issues

Since most of our industries use induction motors, it is essential to develop condition monitoring systems. Nowadays, industries have power quality issues such as sag, swell, harmonics, and transients. Thus, a condition monitoring system should have the ability to detect various faults, even in the presence of power quality issues. Most of the fault diagnosis and condition monitoring methods proposed earlier misidentified the faults and caused the condition monitoring system to fail because of misclassification due to power quality. The proposed method uses power quality data along with starting current data to identify the broken rotor bar and bearing fault in induction motors. The discrete wavelet transform (DWT) is used to decompose the current waveform, and then different features such as mean, standard deviation, entropy, and norm are calculated. The neural network (NN) classifier is used for classifying the faults and for analyzing the classification accuracy for various cases. The classification accuracy is 96.7% while considering power quality issues, whereas in a typical case, it is 93.3%. The proposed methodology is suitable for hardware implementation, which merges mean, standard deviation, entropy, and norm with the consideration of power quality issues, and the trained NN proves stable in the detection of the rotor and bearing faults.

Induction motor speed control in closed loop system with thyristor voltage regulator

There exists a huge class of actuating mechanisms based on induction motors, where the use of a thyristor voltage regulator is relevant. This paper presents studies on the introduction of the ability not only to reduce the starting current of the motor, but also to regulate the speed of rotation. Studies have been conducted on the possibility of obtaining a regulation range of 1:5 using simulation model. The influence of the resolution of the speed sensor on the accuracy of regulation is investigated. Recommendations on the implementation of the developed method of speed control are given