Back Electro Motive Force Estimation Method for Cascade Proportional Integral Control in Permanent Magnet Synchronous Motors

A cascade proportional integral control method with back-electro motive force compensation has been widely used for permanent magnet synchronous motors. In the permanent magnet synchronous motor control, it is important to accurately know the back-electro motive force constant for torque generation as well as back-electro motive force compensation. In this study, a real-time back-electro motive force constant estimation algorithm is developed to improve the velocity tracking control performance. The proposed method consists of a proportional integral controller and a back-electro motive force constant estimator. The proportional integral controller is designed to reduce the velocity tracking error. The back-electro motive force constant estimator is designed to estimate the back-electro motive force constant. It was verified that the estimated back-electro motive force constant converges to the actual back-electro motive force constant. The estimated back-electro motive force constant is applied to the cascade proportional integral controller. To verify the effectiveness of the proposed method, the performance of the proposed method is validated experimentally.

Electro-Magnetic and Structural Analysis of Six-Pole Hybrid-Excited Permanent Magnet Motors

Potentials and limits of the Hybrid-Excitation Permanent-Magnet (HEPM) synchronous machine are dealt with in this paper. A six-pole machine is taken into consideration, and both parallel and series configurations are analysed and compared. Taking advantage of the rotor excitation coils, the permanent magnet (PM) rotor flux can be adjusted according to the operating speed to improve its performance parameters. The electro-magnetic force is analysed in its first harmonic and in the complete shape. Moreover, a comparison between analytical and numerical formulation has been done for the rotor current control. In particular, the speed range is extended, and electro-mechanical torque and power are increased, as well as the efficiency. It will be shown that the rotor flux reduction by using the excitation winding yields an improvement of the motor performance. The main advantage will be obtained during the flux-weakening operations. In this paper, different rotor topologies will be analysed to highlight the advantages and drawbacks of each of them, and how it is possible to achieve higher speed with higher torque and without high saliency ratio. A magnetic network will be introduced to explain the different contribution of the excitation winding to the rotor flux. Furthermore, a comparison of the amount of the volume of PM, copper and iron in internal permanent magnet (IPM) motor and HEPM motor will be analysed. Actually, an analysis of the harmonic content in the electro-motive force even varying the excitation current and a mechanical stress analysis of each machine will be shown. Finally, it will be verified that the excitation losses represent a minimum component of the total losses.

Faraday’s Law and Magnetic Induction: Cause and Effect, Experiment and Theory

Faraday’s Law of induction is often stated as “a change in magnetic flux causes an electro-motive force (EMF)”; or, more cautiously, “a change in magnetic flux is associated with an EMF”. It is as well that the more cautious form exists, because the first “causes” form can be shown to be incompatible with the usual expression V = − ∂ t Φ , where V is EMF, ∂ t is a time derivative, and Φ is the magnetic flux.This is not, however, to deny the causality as reasonably inferred from experimental observation—it is the equation for Faraday’s Law of induction which does not represent the claimed cause-and-effect relationship. Unusually, in this induction scenario, the apparent experimental causality does not match up with that of the mathematical model. Here we investigate a selection of different approaches, trying to see how an explicitly causal mathematical equation, which attempts to encapsulate the experimental ideas of “a change in magnetic flux causes an EMF”, might arise. We see that although it is easy to find mathematical models where changes in magnetic flux or field have an effect on the electric current, the same is not true for the EMF.

Examination of Control Parameters for Medical Grade Insulin Pump

In this work, an attempt has been made to identify the appropriate parameters of Permanent Magnet Direct Current (PMDC) motor for infusion pump. PMDC motor plays important role in medical devices. In this, selection of parameters such as rotor inertia, armature resistance, armature inductance and back electro motive force constant is crucial that help to achieve the required speed. The proposed work uses PID controller (Proportional Integral Derivative) and LQG (Linear-Quadratic Gaussian) control algorithm to evaluate the parameters for transient response of the PMDC motor. It is demonstrated that the chosen parameters are able to reach the required speed with quick rise time by 0.691 seconds by employing LQG.

Topology Comparison Study of Five-Phase Wound-Field Doubly Salient Fault Tolerant Generators

To present the characteristics of pole number and pole shape of the core, the five-phase wound-field doubly salient generators (WFDSGs) with symmetric phase inductance are studied and optimised in this paper, considering the split ratio, slot fill factor and core fringing effect. Based on the principle and structure of the five-phase WFDSGs, the winding induced electro-motive force under different number of poles is theoretically analysed. The constraints for parameter optimisation design including slot fill factor, split ratio and magnetic density characteristic are given. The finite element models of 30/24-pole and 20/16-pole WFDSG are established, and the comparative simulation analysis is carried out. It is pointed out that when the inner and outer diameters of the stator and rotor, the axial length and the maximum magnetic density are constant, the induction electromotive forces of the WFDSGs with different pole numbers and same phase coil number are same. Considering the pole fringing effect, the rotor pole equivalent width is the sum of the rotor pole actual width and 4 times of the air gap. The comparison experiments between the 30/24-pole and 20/16-pole WFDSGs were carried out, which verified the correctness of the theoretical analysis and finite element analysis (FEA).

Design of Vibrate Generator

Vibrate generator is an electric generator, which generate electric by a magnet vibration. This research inspired by the discovery of windbelt by Humdinger. The purpose of this research is to prove electric generator with magnetic vibration, to design low rpm vibrate generator. Electric generator in this vibration is simple, expected to be made society with local material. With an energy source from a ditch drainage or wind, this generator are supposed to generate electricity for one house. Major component generators are bar magnets, springs, wire coils, diode, capasitor and wood board. The principle of generator unit is a magnet attached to the spring and the end of the spring attached to the wooden board. If the spring is vibrated, magnetic vibrations produce a magnetic flux change that penetrates the wire coil who attach beside a magnet. A wire coil penetrated flux magnetic which change with time to produce electro motive force. Every unit generator produce AC and changed to DC by Diode Bridge. The experiment results were one unit cell generator produce 2.2 volt peak to peak, 21.47 Hz, and product duration 0.5second. The design of a low rpm vibrator generator is built from a vibration generator unit arranged and connected in parallel. Each unit vibration generator is vibrated sequentially, in order for a continuous power generation.

A Motion Observer With On-Line Parameter Estimation for Moving-Coil Based Digital Valves in Digital Displacement Machines

In this paper, a method is developed to estimate the parameters and motion of a moving coil actuator in the digital valves of Digital Displacement machines. The parameter estimation is carried out using three simple distinctive schemes from which certain electrical and magnetic parameters may be estimated. The parameter estimation method uses simple adaptation laws to update the moving coil actuator parameters used to estimate the valve plunger motion in an observer. The observer estimates the velocity using the back electro-motive force (back-emf) induced when moving the coil based on current and voltage measurements, but without any mechanical sensors. The valve movement of digital valves is confined by mechanical end-stops enabling estimating the valve position through integration of the estimated velocity relatively accurate. The observer depends on precise knowledge of the electrical dynamics to accurately estimate the valve motion. When the parameters are converged through adaptation the observer proves to be capable of tracking the valve motion relatively accurate, however some deviation occur at the mechanical end-stops of the valve. The parameter estimation method and the observer is implemented and tested off-line when using experimental data obtained from a newly developed digi-valve prototype which uses a moving coil actuator as the force producing element.