Processor evaluation for low power frequency converter product family

Tässä työssä tutkitaan markkinoilla olevia tai lähitulevaisuudessa markkinoille saapuvia prosessoreja käytettäväksi pienitehoisissa taajuusmuuttajissa. Tutkimuksen tarkoitus on selvittää prosessorin sopivuutta sovellukseen, jossa hinta on merkittävä tekijä. Tutkimuksessa esitettyjen vaatimusten perusteella houkuttelevimmat prosessorit otetaan tarkempaan tutkimukseen. Tarkemman selvityksen jälkeen vaatimuksia teknisesti mahdollisimman tarkasti vastaavat prosessorit pyydettiin valmistajalta testattavaksi. Testaaminen suoritettiin lopulta viidelle eri prosessorille, joista kaksi perustui samaan ytimeen. Testaamisen tavoitteena on selvittää prosessorin sopivuus käyttökohteeseensa. Sopivuus testattiin suorittamalla prosessoreissa taajuusmuuttajakäyttöä mallintavaa testikoodia. Tuloksina testikoodin ajamisesta saatiin tietyissä aliohjelmissa kulutettu aika sekä kulutetut kellosyklit. Suorituskyvyn lisäksi testaukseen kuului prosessorikohtaisen kääntäjän aikaansaaman koodin koko. Aliohjelmat sisälsivät sekä aritmeettisia, että loogisia operaatioita, joiden kombinaationa mahdollisimman hyvä sopivuus saatiin selvitettyä.The aim of this thesis is to study processors to be used in a low power frequency converter. Processors under investigation must be currently or in the near future in the market. The purpose is to examine suitability of a processor to an application in which price is an essential factor. The requirements presented in this study will determine which processor will be reviewed more closely. After a precise review, processor vendors was asked to provide as corresponding device as possible to a test. Testing was accomplished eventually with five different processors of which two were based on a same core. The aim of the testing was to investigate suitability of the processors to their target task. Suitability was tested by executing code that models frequency converter application. As a result, spent time and clock cycles are presented in certain functions. In addition to performance, the testing included evaluation of the size of the output code the compilers created. Functions under test consisted of a combination of arithmetic and logic operations that was used to interpret the suitability of the processor

Impact of PWM strategies on RMS current of the DC-link Voltage Capacitor of a dual-three phase drive

The major drawback of usual dual three-phase AC machines, when supplied by a Voltage Source Inverter (VSI), is the occurrence of extra harmonic currents which circulate in the stator windings causing additional losses and constraints on the power component. This paper compares dedicated Pulse Width Modulation (PWM) strategies used for controlling a dual three phase Permanent Magnet Synchronous machine supplied by a six-leg VSI. Since the application is intended for low-voltage (48V) mild-hybrid automotive traction, an additional major constraint arises: the compactness of the drive related to the size of the DC-bus capacitor. Thus, the PWM strategy must be chosen by taking into consideration its impact on both, the motor and the RMS value of DC-bus current

To develop an efficient variable speed compressor motor system

This research presents a proposed new method of improving the energy efficiency of a Variable Speed Drive (VSD) for induction motors. The principles of VSD are reviewed with emphasis on the efficiency and power losses associated with the operation of the variable speed compressor motor drive, particularly at low speed operation.The efficiency of induction motor when operated at rated speed and load torque is high. However at low load operation, application of the induction motor at rated flux will cause the iron losses to increase excessively, hence its efficiency will reduce dramatically. To improve this efficiency, it is essential to obtain the flux level that minimizes the total motor losses. This technique is known as an efficiency or energy optimization control method. In practice, typical of the compressor load does not require high dynamic response, therefore improvement of the efficiency optimization control that is proposed in this research is based on scalar control model.In this research, development of a new neural network controller for efficiency optimization control is proposed. The controller is designed to generate both voltage and frequency reference signals imultaneously. To achieve a robust controller from variation of motor parameters, a real-time or on-line learning algorithm based on a second order optimization Levenberg-Marquardt is employed. The simulation of the proposed controller for variable speed compressor is presented. The results obtained clearly show that the efficiency at low speed is significant increased. Besides that the speed of the motor can be maintained. Furthermore, the controller is also robust to the motor parameters variation. The simulation results are also verified by experiment

New Optimal High Efficiency Dsp-based Digital Controller Design For Super High-speed Permanent Magnet Synchronous Motor

This dissertation investigates digital controller and switch mode power supply design for super high-speed permanent magnet synchronous motors (PMSM). The PMSMs are a key component for the miniaturic cryocooler that is currently under development at the University of Central Florida with support from NASA Kennedy Space Center and the Florida Solar Energy Center. Advanced motor design methods, control strategies, and rapid progress in semiconductor technology enables production of a highly efficient digital controller. However, there are still challenges for such super high-speed controller design because of its stability, high-speed, variable speed operation, and required efficiency over a wide speed range. Currently, limited research, and no commercial experimental analysis, is available concerning such motors and their control system design. The stability of a super high-speed PMSM is an important issue particularly for open-loop control, given that PMSM are unstable after exceeding a certain applied frequency. In this dissertation, the stability of super high-speed PMSM is analyzed and some design suggestions are given to maximize this parameter. For ordinary motors, the V/f control curve is a straight line with a boost voltage because the stator resistance is negligible and only has a significant effect around the DC frequency. However, for the proposed super high-speed PMSM the situation is quite different because of the motor\u27s size. The stator resistance is quite large compared with the stator reactive impedance and cannot be neglected when employing constant a V/f control method. The challenge is to design an optimal constant V/f control scheme to raise efficiency with constant V/f control. In the development, test systems and prototype boards were built and experimental results confirmed the effectiveness of the dissertation system

Alone Self-Excited Induction Generators

In recent years, some converter structures and analyzing methods for the voltage regulation of stand-alone self-excited induction generators (SEIGs) have been introduced. However, all of them are concerned with the three-phase voltage control of three-phase SEIGs or the single-phase voltage control of single-phase SEIGs for the operation of these machines under balanced load conditions. In this paper, each phase voltage is controlled separately through separated converters, which consist of a full-bridge diode rectifier and one-IGBT. For this purpose, the principle of the electronic load controllers supported by fuzzy logic is employed in the two-different proposed converter structures. While changing single phase consumer loads that are independent from each other, the output voltages of the generator are controlled independently by three-number of separated electronic load controllers (SELCs) in two different mode operations. The aim is to obtain a rated power from the SEIG via the switching of the dump loads to be the complement of consumer load variations. The transient and steady state behaviors of the whole system are investigated by simulation studies from the point of getting the design parameters, and experiments are carried out for validation of the results. The results illustrate that the proposed SELC system is capable of coping with independent consumer load variations to keep output voltage at a desired value for each phase. It is also available for unbalanced consumer load conditions. In addition, it is concluded that the proposed converter without a filter capacitor has less harmonics on the currents