Ev tipi buzdolabı için lineer kompressörün elektromekanik analizi

Linear compressors provide an exquisite alternative for the conventional rotary refrigerator compressors. Linear actuators are employed in linear compressors to eradicate the need for the cumbersome rotational to linear conversion mechanisms. This research provides a detailed insight of two application specific linear actuator types: Moving iron (solenoids) and moving magnet linear actuators (MMLAs). A solenoid based linear actuator in combination with springs is proposed for linear oscillations in linear compressors. Switching control of the stator coil enables back and forth motion of the armature. Line pressure, oscillation frequency and stroke provide the baseline for the magnitude of the electromagnetic force which defines the geometric and coil parameters of the solenoid. Reluctance Method is used in this study to establish the relationship of the geometry, coil parameters and the resulting magnetic force. Considering the nonlinearity of magnetic materials, a finite element analysis is presented to estimate the magnetic force in stationary and time dependent domains for static and dynamic characteristics of the solenoid. An experimental setup is used to validate the static and dynamic characteristic responses of the actuator. Moreover, frequency response function is acquired through an impact hammer and accelerometer. The results are validated with electrically actuated solenoid at different frequencies against forces and current values to obtain optimal points of excitation frequency for better performance. MMLAs are superior over other types for their significantly higher efficiency, high thrust density, lower losses, fast responses and smaller time constants. This research presents an analytical model to quantify the electrical as well as mechanical dynamic parameters of MMLA. In the design phase, the presented methodology provides a novel tool to analyze and conclude the design as well as the operating parameters of the actuator to achieve the desired performance. Laplace transformation is applied to obtain the transfer function of the electromechanical system. Furthermore, the equations are converted into the frequency domain to estimate the frequency response for the velocity, stroke and coil current. The effects of the motor constant and the excitation frequency on the magnitude and phase of the dynamic parameters are estimated using Phasors. Additionally, frequency response function of the stroke to current ratio is established to find the optimal point of excitation for achieving better system efficiency. An experimental setup is designed to validate the system model. The acquired experimental results endorse the model for the effects of the motor constant and the excitation frequency. A methodology to estimate the magnetic flux density as well as the magnetic force of MMLA is presented. Considering the simulation time of a 3D FEM softwares, a combination of 2D FEM with the analytical models makes this technique convenient and expeditious. With the help of the 2D FEM, the magnetic flux path is segregated into several loops. Furthermore, the loops are divided into finite zones and the mean values are represented as lines and arcs to estimate the reluctance of each magnetic flux loop. The reluctance models incorporate the effect of armature position to predict the magnetic flux density as a function of stroke positions. A numerical iterative simulation is carried out to incorporate the stator saturation with the help of Ampere's Circuit Law. Additionally, the reluctance models embody the geometric and magnetic parameters of the linear actuator including stator and armature. Consequently, the optimization of the geometric design parameters of the linear actuator is obtainable with a quick numerical simulation. Furthermore, the magnetic force is also estimated numerically with the help of work-energy method. A 3D FEM simulation is executed to compare the computation times. The presented methodology reduces the simulation time drastically. A novel moving magnet linear actuator is proposed for linear oscillations in the linear resonant compressors for household refrigerators. This research provides stator and armature design including CAD model and geometric parameters. Furthermore, the working principle of the proposed actuator is explained. The stator assembly is composed of two reversely wound coils, which are electrically excited with single phase AC power and oscillates the radially magnetized armature. With the help of the electromechanical analytical model, the dynamic parameters such as stroke, velocity and acceleration of the armature are derived. Additionally, the time-dependent current model of the stator winding is proposed. An experimental setup is used to validate these responses at the resonance excitation frequency with the help of sensors. The system kinetics are discussed to estimate the spring, damping, inertial and magnetic forces. A simulation is executed to estimate the time domain responses of these dynamic parameters and the effects of excitation frequency are discussed. The force models are experimentally validated at the resonance frequency excitation. In order to evaluate the performance of the proposed actuator, a comparison of the performance parameters such as efficiency, stroke, current and mass flow rate is demonstrated with the conventional rotary as well as the linear motors for linear compressor application.