Dragos Ovidiu Kisck

Single-Phase Unified Power Quality Conditioner with Optimum Voltage Angle Injection for Minimum VA requirement

The paper deals with an optimized Unified Power Quality Conditioner (UPQC), which aims at the integration of series and shunt active power filters with minimum VA loading of the UPQC. The series active filter is a Dynamic Voltage Restorer (DVR), that operates in two functioning modes. During the unbalanced voltage sag/swell at the input side, the DVR maintains the rated voltage at the load side. It regulates the load voltage with minimum VA loading of the overall UPQC by an optimum voltage angle injection. A technique of achieving both input current distortion compensation, power factor correction and also mitigating the supply-voltage variation (sag/swell) at the load side, is presented as well. To reduce the total cost, but to increase the performance, the system is fully digital-controlled using the fixed-point TMS320F240 digital signal processor. The present paper discusses the VA requirement issues of the proposed UPQC. The performances of the optimum UPQC have been verified on an experimental prototype.

Dynamic Simulation of the Transverse Flux Machine using Linear Model and Finite Element Method

Basically, there are two developments in the field of transverse flux machines, without or with permanent magnets as excitation. Since the main feature of transverse flux machine is the high thrust force density, the linear motor topology including also permanent magnets as excitation is the most promising one. Because the transverse flux machine flux pattern is complicate due to the nonlinearities introduced by the iron core saturation and permanent magnet operating point, the system analysis is not possible by using exact analytical relation. Therefore, the flux linkage and thrust force must be computed via 3D-nonlinear Finite Element Method-FEM, including the obtained results into the linear motor base model using SIMULINK. To have a more realistic approach of the overall drive system, this way is proposed in the paper for dynamic simulation. The dynamic simulation of the two kind of linear motors is presented, in order to demonstrate the advantage of the proposed transverse flux linear motor including permanent magnets over the electrically excited one, as well. The compared results of dynamic simulation are very useful for studying and analyzing different control methods that can be approached for linear motors. The simulation results show the good dynamics and high accuracy of the system model.

A Study on Sensorless Control of Transverse Flux Rotating Motor Based on MRAS with Parameter Estimation

This paper presents a sensorless control and parameter estimation strategies for a Transverse Flux Rotating Motor (TFRM). The proposed sensorless control method is based on a Model Reference Adaptive System (MRAS) to estimate the stator flux. Parameter estimation theory is also applied into the sensorless control method to estimate motor parameters, such as inductances. The effectiveness of the proposed methods is verified by some simulations and experiments.

Modelling of iron losses in salient pole permanent magnet synchronous motors

Today, for the same rated power and speed electrical drives we have a strong competitor to the induction motors. This one it is represented by permanent magnet synchronous motors (PMSM) with salient pole rotors. In this paper are presented dedicated analytical and numerical models for the iron loss effect over the motor performance. It is presented a comprehensive comparison between no-load and loaded conditions test data for all the models presented.

A new nine-level boost PWM rectifier based on stacked multilevel concepts

In this paper a new AC/DC unidirectional switching cell with nine voltage levels is proposed. It is called Stacked-Flying-Capacitors-Coupled-Inductors (SFC2I) and can be connected between an AC current source and a DC voltage source. The novelty of 9L-SFC2I topology is based on two cascaded stages that work at different currents, different voltage and different switching frequency. The first stage contains two diodes that operate at high-current, high-voltage and low-frequency. The second stage works at low-current, low-voltage and high-frequency. It combines the advantages of two stacked multilevel concepts, named Stacked-Flying-Capacitors (SFC) and Stacked-Coupled-Inductors (SCI). The SFC principle reduces the energy stored in flying-capacitors, while the SCI concept naturally sets to zero any difference between the winding currents of the coupled-inductors after each cycle. The operation principle of the 9L-SFC2I cell is verified both for single- and for three-phase unity-power-factor PWM rectifiers.

Design and implementation of an autonomous Wind/PV/Diesel/Battery power system

This paper deals with the design, implementation and experimental analysis of a complex hybrid power system based on renewable energy sources. The optimal design of the Wind/PV/Diesel/Battery power system of 5kW peak power was carried out using Homer software package. The system implementation includes important contributions related to the execution and systemic integration of various components such as: pure sine-wave inverter with galvanic isolation, electronic unit for batteries charging from Diesel-electric generator, intelligent control unit that turns on/off the Diesel-electric generator depending on the battery State Of Charge (SOC), wind turbine emulator composed of a vector control induction motor drive system and a special designed PM synchronous generator, etc.

Rotor-flux model for sensorless vector-control of super-high-speed IPMSM

The paper describes a new algorithm for speed and position estimation for Interior Permanent Magnet Synchronous Motor. The estimator is implemented in a vector controlled system for motion control of a super-high speed (tens of thousands of revolutions per minute) and high power (hundreds of kilowatts) IPMSM. The estimator uses the so-called rotor-flux components in the estimated rotor reference frame that is rotating with the estimated speed. The stator flux components in the estimated rotor reference frame will be calculated using the rotor flux components and q-inductance flux components. To obtain the q-inductance flux, it was used the fictitious/active flux in the actual rotor reference frame that was calculated from the reference of the direct current in the actual rotor reference frame. Using the Lyapunov error states energy function, the speed/position estimator leads to a low position error, which decrease with speed increasing, and no speed error in steady-state and full load operation. It has been developed an experimental vector controlled system consisting of a PWM rectifier and a PWM inverter, in order to assure the regenerative braking, considering that the rated and starting currents are relatively large-hundreds of amps. There are presented some experimental results to prove the operation of the sensorless vector-control system at super-high speed. The algorithm is implemented using a floating-point TMS320F28335-150MHz Digital Signal Controller. This proposed observer can be applied even if the d-q inductances are very low. The presented experimental results show good performances in the dynamic operation with low errors in position estimation and no errors in speed estimation in steady-state operation and different load conditions.