Motor Input Voltage Research Articles

Analysis and Real-Time Testing of a Controlled Single-Phase Wavelet-Modulated Inverter for Capacitor-Run Induction Motors

This paper presents the experimental performance of an inverter-fed single-phase ( 1Phi) capacitor-run induction motor (IM) drive. The new 1Phi voltage-source four-pulse H-bridge wavelet-modulated (WM) inverter is employed to implement the proposed 1Phi motor drive. The WM inverter is operated by switching pulses generated by a unique nondyadic wavelet basis-functions-based multiresolution analysis (MRA). The synthesis part of this MRA has a scale--time structure such that the scale increase/decrease patterns are related to the sign of the first derivative of the reference-modulating signal. Adjusting zero-crossing locations of the first derivative of the reference-modulating signal can change scales of successive dilated and shifted versions of the synthesis scaling function. This approach of changing inverter switching pulses is called the resolution-level control (RLC) strategy, and can be used to adjust the motor input voltage. The proposed 1Phi motor drive incorporating an RLC WM inverter is successfully implemented in real time using a digital signal processor board ds1102 for a 1/2 hp, 1750 r/min capacitor-run IM. The efficacy of the proposed WM-based 1Phi IM drive is verified by both simulation and experimental results at various operating conditions. A performance comparison with a conventional proportional-integral controller is also provided to show the superiority of the proposed technique. Simulation and experimental test results of the proposed WM-based drive demonstrate robust performance, simple implementation, significant dynamic response improvements, and an ability to maintain high-quality inverter outputs.

Probabilistic voltage harmonic analysis of direct torque controlled induction motor drives

In high frequency motor-drives such as direct torque controlled (DTC) induction motor drives, the motor harmonic loss, and electromagnetic interference are largely affected by the spectrum of the motor input voltage. Nonlinear elements in the control loop of DTC drive make harmonic analysis of the drive very complex compared to classical pulsewidth modulated controlled drives. In this paper, a probabilistic method to study the harmonic contents of voltage in DTC of induction motors is presented. The DTC voltage chain is simulated with a random process. Then, the autocorrelation function of voltage vectors is calculated and its power spectrum density is obtained. The effect of flux and torque hysteresis controller bands, machine parameters, and inverter dc-link voltage on the motor voltage spectrum is investigated. Major harmonics in the DTC voltage spectrum are specified and their behaviors are described. Simulation and experimental results are presented to justify the theoretical analysis.

Modelling and Simulation of Energy-Efficient Controllers for Pumps Within Process Industry

The submersible pump is one of the major energy-consuming devices on the utility side. This work considers the modelling, simulation, and control of induction motor-driven submersible pump. A nOnlinear fifth-order model for the motor and a second order for the submersible pump have been used to include nonlinearities such as saturation of magnetic core and efficiency of the pump when powered by sinusoidal and VSI-fed voltage source. The discharge of the submersible pump is very difficult to monitor under closed-loop conditions. Hence a discharge estimator is developed based on motor input voltage, line current, and frequency to predict the quantum of water flow under realistic conditions. A closed-loop discharge controller is designed to control discharge without actually monitoring it. A considerable energy savings is obtained in the closed-loop operation.

On the frequency bandwidth change of a servo system with a gear reducer due to backlash and motor input voltage

The paper analyzes how the frequency bandwidth of a servo system is affected by the input voltage of its motor and the magnitude of the total backlash. The bandwidth of the system is defined as the set of antiresonance frequencies, which appears in the frequency-response characteristic. The change in the frequency-response characteristics is investigated depending on motor input voltage and the magnitude of the total backlash. It is shown that at infinite motor input voltage, the servo system has a bandwidth equivalent to that of a backlash-free system. The amount of the system’s bandwidth reduction due to the backlash changes greatly with the motor input voltage. It becomes possible then to determine the necessary maximum input voltage of the motor and the admissible magnitude of the total backlash to satisfy the desired bandwidth for a servo system with a gear reducer.

Experimental comparison of dynamic FEA results of a permanent magnet brushless DC linear motor

The dynamic behaviour of a permanent magnet brushless DC linear motor (PMBDCLM) is determined to provide the operating potential when applied as a computer numerical control (CNC) feed drive for material removal purposes. Dynamic analysis results are utilized to provide a machine operator interface for milling operating parameters. The five key analyses included here are: (1) the motor slide position versus time and input voltage variants; (2) the velocity of the motor slide versus input voltage variants, (3) the acceleration of the motor slide versus input voltage variants, (4) the normal force versus current density variants under different input voltages, and (5) the development of a user interface providing operating parameters based on FEA results. Preliminary tests were conducted on a BR12-33 DC linear motor model with different input voltages and normal loads. Further tests were conducted on a PMBDCLM-equipped vertical milling machine. The data acquisition system included a digital encoder attached to the motor slide for detecting position and velocity data, a microprocessor board, software, and a microcomputer. Cutting force data were recorded using a force transducer, amplifier, and an A/D board. The solutions, which are obtained from simulation by a finite element analysis (FEA) dynamic module of EMRC-NISA software, provide the data necessary for comparison of experimental results, and are applied to justify feed-rate values. In addition, results obtained are useful in the selection criteria of operating parameters.

PARAMETER IDENTIFICATION OF A SEPARATELY EXCITED OC MOTOR FOR SPEED CONTROL

ABSTRACT This paper presents the application of the least error squares (LES) parameter identification algorithm to. obtain parameters of a separately excited DC motor. The parameters of interest are; the resistance and inductance of the armature windings (Ra.Lt). the motor inertia (J), the damping constant (D), the torque and back emf constant (K) and the load torque constant (μ.). The data used are the motor input voltage, and the corresponding rotor speed. It is assumed that the trajectory of the motor speed as well as the corresponding input voltage are known and sampled at a preselected rate. Simulation results for a separately excited dc motor used in robotics are reported showing good agreement with actual parameter values.

PERTURBATION ANALYSIS OF A SPLIT-PHASE INDUCTION MOTOR IN TIME AND FREQUENCY DOMAINS

ABSTRACT This paper presents a new simplified mathematical model for control analysis of a split – phase single – phase induction motor for fast digital computation of its transient behavior. This model avoids numerical inversion of the machine inductance matrix and allows a large saving in computation time.The non – linear equations are perturbed about an operating point and then rearranged as a multi -input / multi - output time – invariant linear model. This model defines the dynamic behavior about an operating point as function of motor parameters, input voltage and output torque. Dynamic performance of the motor is then predicted and the results are presented. For speed control, this model can be rearranged as a multi – input single – output control system with the aid of frequency analysis. An exact transfer function of such a machine is evaluated and plotted. The effect of changing the load torque from 20 %. up to 140 %. of full load on transfer function is discussed.

The Next Generation Motor Control Method: Direct Torque Control (DTC)

AbstractDirect Torque Control (DTC) is the latest AC motor control method developed by ABB, In Direct Torque Control all switch changes are based directly on the electromagnetic state of the motor. Optimum switching is determined for every control cycle on a time level of 25 microseconds. That is also the main difference between Direct Torque Control and the traditional AC drive control methods. In DTC, there is no separate voltage-and frequency-controlled PWM modulator. The switch positions of the power module are determined by a calculated stator flux and motor torque. The used selection of the switches forces The stator flux in the direction where the reference values of the torque and the stator flux are achieved. The calculation of the stator-flux is based on an accurate motor model and the measurement of the motor input voltage and current. The measurement of the shaft speed is not needed. The reference value of the torque controller either comes from speed controller or is an external reference. Th...

A NEW APPROACH TO PERFORMANCE ANALYSIS OF CHOPPER CONTROLLED D.C. MOTOR DRIVE

ABSTRACT An analytical method for performance analysis of a d.c. separately excited motor fed from a chopper is presented. The motor input voltage is represented as a series of step-voltages with a time phase difference. The system equations are solved to obtain closed-form solutions for motor current and speed, for transient as well as steady state conditions. The method presented is superior to existing methods in that the solution is in closed-form, and does not make recourse to recursive numerical techniques. The solutions for steady state condition corresponding to any set of operating conditions (voltage, chopper duty factor, load torque) can be directly obtained. The computational effort and time needed is therefore extremely small as compared to other methods.