Characterization of Acoustic Resonance in a High Pressure Sodium Lamp

With the last decades, the high pressure sodium (HPS) lamp has been supplied in high frequency in order to increase the efficacy of the lamp/ballast system. However, at some given frequencies, standing acoustic waves, namely acoustic resonance (AR), might develop in the burner and cause lamp luminous fluctuation, extinction and destruction in the most serious case. As we seek for a control method to detect and avoid the lamp AR some main characteristics of the acoustic resonances in a 150W HPS lamp are presented in this paper,. The first one is the characteristic of the lamp AR threshold power, the second one is the differences between forward and backward frequency scanning effects during lamp open loop operation. Thirdly, lamp AR behaviour in closed loop operation with an LCC half bridge inverter will be presented and leads to a new point of view and a change in the choice of the AR detection method. These characteristics allow us to further understand the AR and to better control the lamp

Multi phase system for metal disc induction heating: modelling and RMS current control

This paper presents a multi phase induction system modelling for a metal disc heating and further industrial applications such as hot strip mill. An original architecture, with three concentric inductors supplied by three resonant current inverters leads to a reduced element system, without any coupling transformers, phase loop, mobile screens or mobile magnetic cores as it could be found in classical solutions. A simulation model is built, based on simplified equivalent models of electric and thermal phenomena. It takes into account data extracted from Flux2D® finite element software, concerning the energy transfer between the inductor currents and the piece to be heated. It is implemented in a versatile software PSim, initially dedicated to power electronic. An optimization procedure calculates the optimal supply currents in the inverters in order to obtain a desired power density profile in the work piece. The paper deals with The simulated and experimental results are compared in open-loop and closed loop. The paper ends with a current control method which sets RMS inductor currents in continuous and digital conditions

Fuzzy controller tuning of a boost rectifier unity power factor correction by experimental designs

This paper shows the validity of experimental designs as an efficient on-site tuning tool for fuzzy controllers, dedicated to electrical engineering applications with multi-objective criteria. Our purpose is to improve the input and output system characteristics that is to say the global quality of the electrical power in a boost rectifier with unity power factor correction. The desirability notion combines here time dynamic and harmonic criteria, it illustrates the trade-off that has to be satisfied between the different properties

Renewable electricity production with some wasted second-life components

Renewable energy systems are playing an important role to reduce CO2 emission and provide electricity for daily use in rural areas. But brand new components with up-to-date technology could be far too expensive for many potential users (rural communities in many developing countries. As a consequence, turning waste components into energy production systems could be a good opportunity to reach these two goals simultaneously. In this paper, a disposal induction motor, a car battery and an Uninterrupted Power Supply (UPS) are combined together in order to generate electrical energy from pico-hydro power. The control of the RMS output voltage and frequency is presented with a comprehensive state-space model, simulation and experimental validation results are provided

Lifespan Modeling of Insulation Materials for Low Voltage Machines: films and twisted pairs

This paper deals with the modeling of insulation material lifespan in a partial discharge regime. Accelerated aging tests are carried out to determine the lifespan of polyesterimide insulation films under different various stress conditions. The insulation lifespan logarithm is modeled as a function of different factors: the electrical stress logarithms and of an exponential form of the temperature. The model parameters, or so-called factor effects, is estimated on a training set. The significance of the factors is evaluated through the analysis of variance (ANOVA). In a first step, the design of experiment method (DoE) is considered. The associated lifespan model is linear with respect to the factors. This method is well-known for reducing the number of experiments while providing a good accuracy. In a second step, the response surface method (RSm) is considered. This method takes also into account some second order terms and thus possible interactions between the stress factors. Performance of the two methods are analyzed and compared on a test set. </p

Stator Current based Indicators for Bearing Fault Detection in Synchronous Machine by Statistical Frequency Selection

The aim of this paper is to present some indicators developed for efficient detection of bearing defaults in high speed synchronous machines using a stator current analysis. These actuators are used in an air conditioning fan for aeronautic applications. The signatures of the bearing defects appear through an increase in amplitude of specific current harmonics multiples of the rotation frequency. From an experimental comparison between a healthy fan and another with damaged bearings, an automatic frequency selection is performed to identify the frequency ranges for which the energy is the most sensitive to the considered faults. From these frequencies, several strategies are investigated to propose a suitable indicator for the bearing fault detection. A post-processing algorithm is then developed and tested for different measurements, different types of faults and different operating points, to ensure the robustness of the proposed method

Mono inverter dual parallel PMSM - Structure and Control strategy

This paper presents a dual parallel connected PMSM fed by a single power inverter. Both motors have to respect the synchronism even if they have different load torque. The rotor position of the two motors that is to say the load applied on each motor are consequently permanently compared. The motor with the highest load is set as the master one and is auto-piloted. The other one which has the same applied voltage has the same electric pulsation and so the same speed rotation. The change of the master choice is done whereas the load applied on the machine is changing so that oscillations appear during this change. The steady state is however rapidly attained and the synchronism stays always observed

Design of Experiments predictive models as a tool for lifespan prediction and comparison for enameled wires used in low voltage inverter-fed motors

Since the development of power electronic components, which allowed the manufacturing of reliable and efficient inverters, variable speed drives using inductive motors have become more and more popular. The PWM technique has proven to be a very effective method of rotational speed control. However, the fast changing voltage pulses, with very steep slopes (in the order of a few kV/μs), has brought new hazards for the electrical insulation system of such motors. Very high frequency harmonic components of PWM voltage will result in significant overvoltage due to an impedance mismatch between the cable and the motor. As an effect, the voltage seen by some parts of the insulation system may exceed the Partial Discharge Inception Voltage (PDIV) stating localized partial discharges activity. The aim of this paper is to investigate and analyze the aging process of the enameled wire exposed to different factors and to propose a method allowing to predict their lifespans in given conditions. This study introduces a prediction based on the Design of Experiments method and the statistical Weibull distribution. Thanks to the model obtained with short multi-stress aging tests, it is possible to predict the results of significantly longer ones. Moreover, the adapted methodology is proposed that allows to predict the scatter of the long tests basing on the short-time results dispersion. The same approach is used to compare different products between each other and rank them. All model predictions are compared with the experimental data in order to prove the model accuracy

Mono inverter multi-parallel permanent magnet synchronous motor:structure and control strategy

This study presents a new and original Mono inverter multi-parallel permanent magnet synchronous motor (PMSM) system. To obtain the stability of such a system, each of the motor synchronisms should always be respected regardless of their load torque. In this case, only one motor, called ‘master motor’, will be self-piloted. If the chosen master motor is the one with the highest applied load torque, synchronism is respected for each of the motors. To find this machine, a solution that compares the rotor positions is thus developed. Experimental results are given for a system with two PMSM plugged in parallel. The proposed solution can, however, be applied to systems whatever the motor numbers; therefore additional simulations are provided for a four-PMSM system