Nominal Speed Research Articles

Single observer speed sensorless field weakening control of two parallel motors

Two induction motors with parallel connected stator windings supplied by a single inverter (single observer) with a field weakening control system. The objective of this study is to propose a torque production speed sensorless vector control technique for each parallel connected rotor by adding field weakening control to improve the performance of each motor and reducing the number of adaptive observers on each motor to a single observer. Design of a rotor flux-oriented control (RFOC) system. Simulation results with the C-MEX S-function of MATLAB/Simulink 2015b show that the proposed method works better and can be operated at speeds that exceed the nominal speed of the motor.

Design and experimental characterization of a propane-based reversible dual source/sink heat pump

The current paper presents the design and energy performance analysis of a propane-based reversible Dual Source/Sink Heat Pump (DSHP). DSHPs offer an alternative to conventional water to water and air to water heat pumps, leveraging the strengths of both technologies in an efficient manner. The developed prototype incorporates an innovative Dual Source/Sink Heat eXchanger (DSHX), enabling the unit operating in various modes, including space heating, space cooling, and domestic hot water production using brine, air or both simultaneously as a source/sink. The DSHX serves as as both a condenser or an evaporator, directly rejecting or absorbing heat from air and/or brine. By eliminating secondary loops and defrost cycles, the DSHX minimizes energy losses. The main novelty of this work lies in the DSHX that integrates external units typically duplicated in DSHPs into a single component, eliminating the need for split refrigerant flow rates, thus avoiding maldistribution, refrigerant charge increase and draining valves. A steady state experimental campaign was conducted in a climatic chamber to characterize the DSHP prototype and validate the DSHX performance models. Heating capacity up to 11.2 kW and COP values up to 4.7 were achieved at nominal compressor speed by supplying hot water at 35 °C with an ambient temperature of 7 °C. Similarly, when producing cold water at 7 °C, cooling capacity and EER reached 9.8 kW and 3.6, respectively, at nominal compressor speed using air as heat sink at 35 °C. The effects of various operating parameters on the overall coefficient of performance and heat duty in both heating and cooling modes, considering air or brine as heat source/sink are analyzed in detail. Results demonstrate enhancements of approximately 15 % in capacity and efficiency compared to earlier work. Moreover, four deterministic models were created in order to predict the behaviour of the DSHX and validated against experimental results, reaching deviation values below 15 %.

Comparative Study of TLP250 and IR2132 Driver-Based Inverter for Induction Motor Driving

As time progresses, electric motors are used for industrial or commercial purposes. The need for a motor that is robust, simple, and easy to maintain has been answered by creating an induction motor that can handle the purpose. At the beginning of its use, induction motors were more often used at constant speeds. Using an inverter becomes one of the solutions at hand to control the induction motor. Nowadays, most inverters are controlled by the SPWM (Sinusoidal Pulse Width Modulation) method. This method can adjust the output voltage and frequency by setting the carrier signal's frequency value and the reference signal's amplitude. A driver circuit is needed to implement an SPWM-based inverter. This driver circuit is needed to isolate the power circuit from the controller. Moreover, this circuit is also used to increase the microcontroller output signal to trigger the IGBT gate switch. The IR2132 and TLP250 drivers are often used in three-phase inverter applications. These drivers have advantages and disadvantages. This paper discusses the capabilities of these two drivers when applied to a three-phase inverter that functions as an induction motor drive. This inverter-controlled induction motor is advantageous because it can be rotated at a nominal speed and frequency.

Laboratory Tests on the Possibility of Using Flax Fibers as a Plant-Origin Reinforcement Component in Composite Friction Materials for Vehicle Braking Systems.

Braking systems are extremely important in any vehicle. They convert the kinetic energy of motion into thermal energy that is dissipated into the atmosphere. Different vehicle groups have different nominal and maximum speeds and masses, so the amount of thermal energy that needs to be absorbed by the friction pads and then dissipated can vary significantly. Conventional friction materials are composite materials capable of withstanding high temperatures (in the order of 500-600 °C) and high mechanical loads resulting from braking intensity and vehicle weight. In small vehicles traveling at low speeds, where both the amount of thermal energy and its density are limited, the use of slightly weaker friction materials with better ecological properties can be considered. This work proposes a prototype composite friction material using flax fibers as reinforcement instead of the commonly used aramid. A number of samples were prepared and subjected to laboratory tests. The samples were prepared using components of plant origin, specifically flax fibers. This component acted as reinforcement in the composite friction material, replacing aramid commonly used for this purpose. The main tribological characteristics were determined, such as the values of the coefficients of friction and the coefficients of abrasive wear rate. For this purpose, an authorial method using ball-cratering contact was used. The results were analyzed using statistical methods. It was found that the composite material using flax fibers does not differ significantly in its tribological properties from conventional solutions; so, it can be assumed that it can be used in the vehicle's braking system.

Power Curve Determination and Electrification of Powertrain System of Harvester Crane Swinging

The work deals with the determination of the power curve for driving the swinging of the hydraulic crane of the harvester and the subsequent replacement of the hydraulic motor with an electric motor for the possibility of recuperating braking energy. For this purpose, the hydraulic circuit of the crane slewing gear was measured with flowmeters during its rotation between the angles –105° to +105°, –90° to +90° and –36° to +22°. The power was calculated from the measured values. The maximum power needed to swing the harvester crane was 9720 W. With this power, the torque reached 187.98 Nm. The average value of the power needed to swing the hydraulic crane was only 2472 W at a torque of 47.81 Nm. From these values, a synchronous electric motor with permanent magnets with a nominal speed of 2000 rpm (rotation per minute) and a power of 3246 W emerged as suitable for replacing the hydraulic motor. The use of an electric motor would, however, require a planetary gearbox with fast input speeds that would then be reduced to slow output speeds. The research results demonstrated the possibility of using an electric motor to swing the hydraulic crane during the work cycle of the harvester for the use of energy recovery from crane braking and thus the possibility of reducing fuel consumption and emissions.

Computational study of gas-dynamic approach for noise reduction in atwo-stroke engine’s exhaust system

BACKGROUND: The traditional approach to designing exhaust mufflers relies heavily on energy dissipation. In the "gas-dynamic" approach, the flow of exhaust gases is equalized by introducing long channel(s) into the muffler to separate impulses and shift them in time. It is assumed that such mufflers will provide noise reduction without creating significant backpressure. AIMS: To evaluate the potential of the "gas-dynamic" approach to reducing the noise level of two-stroke internal combustion engines. MATERIALS AND METHODS: The study was carried out using computational models. The processes in the gas-air tract of the piston engine were calculated using a one-dimensional (1D) model. The noise characteristic was the effective sound pressure at a specified point in the environment, calculated using 2D model of propagation of disturbances in elastic medium. The object of study was a two-stroke gasoline two-cylinder engine RMZ-551i, with a resonator (providing gas-dynamic supercharging) and a muffler. Initially, the parameters and sound pressure level of the engine with the stock muffler at full load and close to nominal engine speed were calculated. Then, the structure of the stock muffler was modified by adding a "tuned" channel between its two chambers. The parameters of the modified muffler were optimized based on the criterion of reducing gas pulsations at the outlet to the atmosphere. The noise reduction of the muffler implementing the gas-dynamic approach was evaluated relative to the stock muffler and expressed in terms of sound pressure levels in dB. Performance and levels of sound pressure were finally calculated over a wide range of engine speeds. RESULTS: According to the computational estimate, the optimal implementation of the gas-dynamic approach in the muffler reduces exhaust noise by 7 dB, while engine power decreases by 2.5%. Calculation of the sound pressure level based on the external speed characteristic showed that at an engine speed of 3000 rpm, the calculated sound pressure exceedsby 8 dB the minimum (99 dB) obtained for the optimally "tuned" muffler at an engine speed of 5000 rpm. It is suggested that the gas-dynamic approach with optimization is also applicable for uniform noise reduction over a wide range of engine speeds, with a more complex structure of the exhaustmuffler. CONCLUSIONS: Theoretical evaluation of a muffler with a tuned channel connecting its two chambers was carried out, with a two-stroke engine RMZ-551i with a stock muffler as a basis for comparison. At the optimum point on the speed characteristic, the exhaust noise was reduced by 7 dB, while the calculated power decrease was insignificant. The authorsnote the suitability of the methodology for rapid assessments and automated computational optimization of mufflers that utilize wave effects. They also point out the limitations of the models used, which require validation or rather calibration based on experimental data, and the need for the development of applied models of acoustic effects and measuring devices for domestic CAE packages.

Algebraic Speed Estimation for Sensorless Induction Motor Control: Insights from an Electric Vehicle Drive Cycle

Induction motors (IMs) must meet high reliability and safety standards in mission-critical applications, such as electric vehicles (EVs), where sensorless control strategies are fundamental. However, sensorless rotor speed estimation demands improvements to overcome filtering distortions, tuning complexities, and sensitivity to IM model mismatch. Algebraic methods offer inherent filtering capabilities and design flexibility to address these challenges without introducing additional dynamics into the control system. The objective of this paper is to provide an algebraic estimation strategy that yields an accurate rotor speed estimate for sensorless IM control. The strategy includes an algebraic estimator with single-parameter tuning and inherent filtering action. We propose an EV case study to experimentally evaluate and compare its performance with a typical drive cycle and a dynamic torque load that emulates a small-scale EV power train. The algebraic estimator exhibited a signal-to-noise ratio (SNR) of 43 dB. The closed-loop experiment for the EV case study showed average tracking errors below 1 rad/s and similar performance compared to a well-known sensorless strategy. Our results show that the proposed algebraic estimation strategy works effectively in a nominal speed range for a practical IM sensorless application. The algebraic estimator only requires single-parameter tuning and potentially facilitates IM model updates using a resetting scheme.

Transonic Compressor Darmstadt Open Test Case: Experimental Investigation of Stator Secondary Flows and Hub Leakage

Abstract The future trend of clean sky aviation has led to a smaller core engine, resulting in highly loaded stages with increased relative tip gaps and leakage flows, which causes a reinforced influence of secondary flow phenomena. This article experimentally investigates the secondary flow effects in the 3D-optimized shrouded stator of the TUDa-GLR-OpenStage, representative of a transonic high-pressure compressor front stage, and its susceptibility to typical hub leakage flows. The impact of stator hub leakage on efficiency and total pressure ratio is investigated for several operating speeds, from subsonic to nominal transonic operating conditions. Steady five-hole probe and time-resolved virtual multi-hole probe measurements at different operating conditions at nominal speed are conducted to investigate the underlying loss mechanisms. The leakage mass flow is determined using the measured pressure difference within the fin seal. Steady results show that the optimized 3D stator effectively suppresses the hub corner separation compared to the predecessor 2D stator, but its performance is further limited by a near-tip separation. With the increased stator hub leakage (at a leakage-to-main flow ratio of about 0.4%), the compressor isentropic efficiency generally drops (by about −0.5%) at the full operating range due to an enhanced hub corner separation effect. However, the increased leakage also helps alleviate the tip-corner separation when operating near stall, leading to a smaller efficiency penalty under these conditions. Unsteady results reveal the sensitivity of transient compressor performance to the passing rotor wake, but limited interaction between this phenomenon and the increased leakage is observed. These findings provide insight into the stator hub leakage-related penalties on the compressor aerodynamics efficiency.

DFIG in Wind Energy Applications with High Order Sliding Mode Observer-based Fault-Tolerant Control Scheme using Sea Gull Optimization

This paper describes a new method for maximizing power extraction from a wind energy conversion system (WECS) by using a doubly fed induction generator (DFIG) that operates below nominal wind speed. To maximize the collected power of a wind turbine (WTG) exposed to actuator failure, a fault-tolerant high-order sliding mode observer (HOSMO) and Seagull Optimization Algorithm with a model predictive controller (MPC) technique is proposed. Evaluate both the real state and the sensor error simultaneously using a higher-order sliding-mode observer. Active fault tolerant controllers are designed to regulate wind turbine rotor speed and power in the presence of actuator defects and uncertainty. With the growing interest in employing wind turbines (WTGs) as the primary generators of electrical energy, fault tolerance has been seen as essential to improving efficiency and reliability. This research focuses on optimal fault-tolerant pitch control, which is used to modify the pitch angle of wind turbine blades in the event of sensor, actuator, and system failures. A Seagull Optimization Algorithm (SOA) is proposed to tune controller parameters to improve the performance of WT. The proposed method has achieved 92% of power tracking performance when compared to existing method.

Transonic compressor Darmstadt Open Test Case – unsteady aerodynamics and stall inception

Predicting unsteady aerodynamics and related phenomena in the vicinity of the stability limit of transonic compressors has been a challenging topic within the turbomachinery community since decades. To improve numerical tools and prediction capabilities the Transonic Compressor Darmstadt Open Test Case has been introduced to provide a reliable validation test data set for steady and unsteady compressor aerodynamics. This work investigates the unsteady aerodynamics before the occurrence of rotating stall within the TU Darmstadt OpenStage compressor rotor and introduces unsteady wall pressure data to the Darmstadt Open Test Case. Exemplary pre-stall aerodynamics and stall inception are investigated for nominal (transonic) and part speed (subsonic) operating conditions, comprising the analysis of the unsteady static pressure field at the rotor tip as well as spectral analysis of the corresponding pressure signals during transient throttling maneuvers. To capture the rotor tip flow field, the rotor casing is instrumented with axially arranged flush mounted time-resolving wall pressure transducers. To determine propagation speeds of occurring phenomena, additional circumferentially distributed sensors are considered. Vibration monitoring shows no significant flutter or non-synchronous blade vibration, prior to the occurrence of rotating stall. Thus, this work focuses on aerodynamics, such as the interaction of secondary flow and shocks.

Improving the OWC Wave Energy Converter Power Take-Off Efficiency throughout Experimental and Numerical Characterisation of an SCIG

The increasing interest in the use of renewable energy technologies is directing attention towards the potential contribution of marine energy technologies, especially ocean wave energy, to world energy demand. While open-sea demonstrations of full-scale devices have been carried out to validate several technologies, the focus now is shifting to optimising the components for efficiency and reliability. The efficiency of the electrical generator plays a crucial role in wave-to-wire numerical models for converting wave energy into usable electricity. It provides essential data that enables the industry to reduce technical risks and uncertainties. Wave-to-wire models typically simplify the generator’s efficiency through assuming a single curve based on the load. This curve is usually provided by the machine manufacturers for the nominal rotational speed. However, the rotational speed varies in the case of air turbines used in OWC devices. Therefore, to accurately estimate decision variables derived from these models, a comprehensive efficiency map is necessary. This map should demonstrate the performance at different rotational speeds and loads, as it directly influences the estimation of key parameters. The main objective of the present work is to improve the generator behaviour of an OWC for different generator operation regimes. For this purpose, a numerical model of the generator’s efficiency will be developed throughout the segregation of losses and validated experimentally. Finally, an optimal control law will be presented to maximise the electrical power output of the wave energy converter, considering the efficiency of both the generator and the turbine.

Characterization of a NEG cartridge under high pressure conditions

The development of advanced sintered pumping elements based on the ZAO® alloy, characterized by a high affinity towards hydrogen and its isotopes, make Non Evaporable Getter (NEG) pumps particularly appealing for applications in fusion research, which typically deal with large fluxes of these gaseous species. NEG getters show high pumping speeds and capacity, excellent reliability with ability to withstand a high number of loading and unloading cycles without showing any type of failure, ease of integration within a complex system (such as a fusion reactor) because of their high specific properties and the simplicity of the mechanism that regulates its operation. These properties make NEG technology particularly suitable for the development of compact, efficient and easily scalable solutions, which are also very safe, since the release of absorbed hydrogen is prevented in the case of power outage or subsystem failures, as it can occur only by providing an adequate amount of heat to the getter material. This paper reports the results of an experimental campaign conducted on a new type of NEG pump, aimed to obtaining an accurate characterization in response to different operating conditions. Hydrogen pumping speed was investigated in a range of pressures of particular interest for the activities of the Divertor Tokamak Test facility (between 0.1 and 10 Pa). The influence of nitrogen absorption and getter material operating temperature on the pumping performances of the NEG pump were also examined. Finally, numerical simulations have been performed to estimate the nominal pumping speed of the NEG pump, that is, the one acting at the absorbing surface, stripped of the effects of the conductance of the paths from the pump NEG to the pressure gauges.

Modulation Techniques and Coordinated Voltage Vector Distribution: Effects on Efficiency in Dual-Inverter Topology-Based Electric Drives

The increasing popularity of electric drives employing an isolated dual-inverter (DI) topology is motivated by their superior DC-link voltage and power utilization, fault-tolerant operation, and potential for multilevel operation. These attributes are significant in battery-powered transportation, such as electric vehicles and aviation. Given the considerable freedom in modulation and control of the DI topology, this paper researches the impact of reference voltage vector distribution between the two individual inverters. The study also evaluates the influence of two well-established asynchronous modulation strategies—Space Vector PWM (SVPWM) and Depenbrock’s Discontinuous Modulation (DPWM1). Since simulation tools nowadays play a crucial role in power electronics design and concept verification, the results are based on extensive and detailed models in Matlab/Simulink. Employing the basic field-oriented control of a 12 kW induction motor with precisely parameterized SiC switching devices for accurate loss calculation, this research reveals the possibility of significant energy savings at multiple operating points. Notably, optimal efficiency is achieved when one inverter operates up to half of the nominal speed while the other solely establishes a neutral point for the winding. Moreover, the results highlight DPWM1 as a superior strategy for the DI topology, showcasing reduced converter losses. Overall, it is shown that the system’s losses can be significantly reduced just by the design of the voltage vector distribution in the drive’s operating range and the modulation strategy selection.

Two-speed Synchronous Generator for Special Purposes

This paper deals with basic performances of a design of a two-pole three-phase 40MVA synchronous generator. The generator is designed to test three-phase and single-phase high power transformers aimed to work within 50 Hz and 60 Hz network frequency. This means that the generator will operate at two nominal speeds, at 3000 rpm and 3600 rpm, with nominal power of 40 Mvar induction load when rating with symmetrical three-phase load. The additional requirements relate to constant operation with two-phase 25 MVA load and single-phase 13.5 MVA load, since for testing single-phase and special transformers phase connection you like will be used. In the course of designing, special attention was paid to correct dimensioning of the damper rotor winding as well as to the geometry of stator windings, rotor and air gap, which in the end will produce minimum voltage wave distortion, i.e. generator voltage wave shape with harmonious content less than 1% (as it was demanded).

The Financial Aspects behind Designing a Wind Turbine Generator

This article investigates the construction of a wind power generator requiring the lowest possible cost. The proposed model is an Axial Flux Permanent Magnet (AFPM) Synchronous Machine, which contains two iron rotors and a coreless stator between them, constructed from resin. The scientific contribution relates to the coupling of economic and technical parameters, which will clarify the feasibility, i.e., a wind turbine construction capable of producing approximately 3.5 KW, using a simple mill and a generator of nominal rotor speed 100 rpm. Such studies are few in international literature and mainly concern low levels of rotor speed in relation to the produced output power. For the generator dimensioning, analytical equations are used, while the type and the dimensions of the magnets are determined, before the start of dimensioning. The authors carried out research in the international market, ending up with specific cost-effective magnets, while trying to adjust the remaining dimensions and materials of the machine based on these cost-effective magnets and the aforementioned nominal values of the generator. The machine, whose dimensions are derived by analytical equations, was simulated and analyzed using the Two-Dimensional Finite Element Method (2D-FEM) and the Three-Dimensional Finite Element Method (3D-FEM), for comparison purposes. Moreover, an economic analysis of the generator and its individual parts was conducted. Finally, a novel idea for reducing the total generator cost is proposed, by replacing the rotor disks with rings. The investigation revealed that analytical equations can predict with satisfactory accuracy the generator’s parameters. In addition, as permanent magnets are the most expensive materials in the construction, their predetermination using low-cost magnets can reduce the construction cost. Finally, the proposed concept of a ring-shaped rotor instead of a disk rotor, provides a cost reduction of up to 20%.

ТЕОРЕТИЧЕСКОЕ ОБОСНОВАНИЕ ОПЕРАТИВНОГО МЕТОДА ДИАГНОСТИРОВАНИЯ ДИЗЕЛЬНЫХ ДВИГАТЕЛЕЙ И ИХ ТОПЛИВНОЙ АППАРАТУРЫ

It is convenient to study the quality of diesel engines by analysing the distribution of fuel supplied to the diesel engine. This is explained by the fact that fuel consumption is quite convenient to determine using 90 simple weight or volumetric methods. The difference between the amounts of fuel supplied to the diesel engine and spent on internal losses represents the consumption spent on the useful work. The internal energy losses of a diesel engine consist of thermal and mechanical ones, assessed by its indicator and mechanical efficiency. Their product, called effective efficiency, determines the fuel efficiency of the diesel engine as a whole. Only the consumption of fuel supplied to the diesel engine and spent idling can be determined operationally. Other costs can only be found in workshop conditions when carrying out tests using complex braking systems. Bashkir State Agrarian University has proposed a method for fast diagnosing and regulating fuel equipment to solve this problem. It is based on using the diesel engine itself as an adjustment stand when it operates at nominal speeds without load on parts of the cylinders, allowing fuel to flow into one of the operating cylinders. In this case, the load for the operating cylinders is the internal mechanical and gas-dynamic energy losses of the diesel engine. The high accuracy of the proposed method is achieved, on the one hand, by ensuring high stability of nominal idle speed through adjusting the number of missed injections and, on the other, by adjusting the fuel equipment with its own fuel lines and injectors and taking into account the injection back pressure. Thanks to this, changes in the adjusted parameters of the fuel equipment when running on diesel are excluded. The particular value of the method is that it allows determining mechanical efficiency through hourly fuel consumption and can be successfully used in both direct-acting and battery-type fuel systems.

МЕТОДЫ МАТЕМАТИЧЕСКОГО МОДЕЛИРОВАНИЯ ХАРАКТЕРИСТИКИ МОЩНОСТИ ВЕТРОЭНЕРГЕТИЧЕСКОЙ УСТАНОВКИ

At the moment, the Russian wind energy market uses wind power plants, which have their own range of parameters and characteristics. There are various methods by which it is possible to calculate electricity generation based on nominal capacity and wind potential data for the site where the construction of a wind farm is planned. But for this, it is necessary to have a power characteristic for a particular wind power plant. Often the nominal wind speed is used to build it. (Research purpose) The research purpose is analyzing methods for modeling power characteristics for wind power plants with various control systems. (Materials and methods) Considered cases for pitch control and stall control systems. Analytical and computational methods were applied, in particular the bin method and the linear interpolation method. (Results and discussion) Formulas were defined for calculating wind speed and active power to construct power characteristics using the bin method. Approaches to modeling the power characteristic and its approximation are described, while taking into account the features of power management systems, which are divided into active, passive and combined. The results of calculations were presented in tabular form, indicating that with passive and combined control systems cubic polynomials cannot be used due to the large approximation error, common methods for determining power and generation do not always give accurate results. (Conclusions) Several mathematical models used to analyze the power characteristics of wind power plants have been cited. It has been shown that they can be used to predict the output for specified sites with a known wind regime.

АНАЛИЗ ЭНЕРГОНАСЫЩЕННОСТИ РЫНКА СЕЛЬСКОХОЗЯЙСТВЕННЫХ ТРАКТОРОВ РОССИЙСКОЙ ФЕДЕРАЦИИ

The modern level of technical development makes it possible to produce high-power agricultural tractors and at the same time reduce the specific weight of the unit. Most of the US and European markets are represented by tractors up to the 2nd traction class, while in Russia there is a steady increase in the use of tractors of traction class over 2. It is known that an increase in the power of machine-tractor units leads to an increase in nominal operating speeds, as well as fuel and lubricants costs. There is also a decrease in the total mass of machine-tractor units, which, while increasing power, reduces the efficiency of using the unit when performing agrotechnological operations. Underloading of a high-power and low-weight unit leads to incomplete and irrational use of the life of machine-tractor units laid down by the manufacturer. (Research purpose) The research purpose is determining the share of high-power equipment in the markets of the Russian Federation. (Materials and methods) Studied the market of machine-tractor units in the Russian Federation on the basis of well-known works and information on technical data provided in open sources by manufacturers. (Results and discussion) We obtained diagrams describing the percentage of world and domestic agricultural tractor manufacturers in the Russian markets, their price range, the share of countries producing tractors of different traction classes, the number of high-power equipment for various traction classes. Based on the analysis of technical characteristics, we have compiled a summary table of the energy saturation of machine-tractor units in the Russian market. The specific power of each tractor model under study was calculated. The specific power of tractors within each traction class was brought. (Conclusions) It was shown that the results obtained indicate a high specific power of the tractor market in the Russian Federation.

ОПРЕДЕЛЕНИЕ ЭФФЕКТИВНОЙ МОЩНОСТИ ПО ВЕЛИЧИНЕ РЕАКЦИЙ ОПОР ДВИГАТЕЛЯ ПРИ РАБОТЕ В РЕЖИМЕ СВОБОДНОГО РАЗГОНА

Ensuring high performance of transport-technological machines is possible to achieve only with timely assessment of the energy performance of the engine. The problem of measuring effective torque and effective power is currently unsolved. The paper proposes a method for determining the effective power by the magnitude of engine support reactions. The purpose of the research is to improve the method of determining the effective power by the value of the reactions of the supports of an internal combustion engine when operating in free acceleration mode. The results obtained have established that the effective power of an engine can be determined by the value of support reactions averaged over 180°. Engine power varies from 0 to 61 kW in the crankshaft speed range of 600...2184 min–1 . Deviation of calculated and experimental values of power at nominal crankshaft speed is not more than 1.71 kW or 2.85 %. The results of experimental studies can be used to improve the method of determining the engine power under operating conditions.

Influence of PWM techniques on an induction motor powered by three-phase voltage inverter

This paper presents a study on the influence of different PWM control techniques for a voltage inverter on an induction motor. In the first step, we implemented the PWM techniques using the Xilinx System Generator tool, which allows implementation on the FPGA board. Then, we compared the different PWM techniques and their effects on the operation of the induction motor. The results obtained showed that the motor reached the nominal speed, with the best results for starting current and torque achieved by the Triplen Injection PWM (THIPWM) technique compared to the other two techniques, enabling good motor performance.