Andrew Trentin

Control and Implementation of a Matrix-Converter-Based AC Ground Power-Supply Unit for Aircraft Servicing

This paper deals with the design, control, and implementation of a three-phase ground power-supply unit for aircraft servicing. Instead of a classical back-to-back converter configuration, a three-phase direct ac-ac (matrix) converter has been used as the power conditioning core of the power supply, working in conjunction with input and output LC filters. An optimized control system in the ABC frame employing a repetitive controller has been successfully implemented, taking into account both the transient and steady-state performance targets together with the system effectiveness under extreme unbalanced conditions. Extensive experimental tests on a 7.5-kVA prototype prove the efficiency of the designed system in meeting the high demanding civil and military international standards requirements.

Large-Signal Model for the Stability Analysis of Matrix Converters

The interest in using the matrix converter (MC) for motor drive applications and energy conversion systems is steadily increasing due to its main advantage of performing a direct coupling between two three-phase alternating current sources without the need of an intermediate direct current bus. This characteristic, together with the presence of inductance-capacitance input filters and the feedforward compensation of the input voltage variations, might yield unstable operation in electrical drives. In this paper, a theoretical analysis of MCs based on a large-signal model is presented with the aim to show which parameters may affect the stability and to explain the reason of this phenomenon. The theoretical analysis is supported by several experimental tests carried out on an MC prototype

Theoretical and experimental investigation on the stability of matrix converters

Matrix converters perform a direct coupling between two ac sources without the need for energy storage components. This characteristic, together with the presence of L-C input filters and the feedforward compensation of the input voltage variations, may determine unstable operation as the power delivered to the load exceeds a limit value. In this paper, a theoretical analysis of the stability of matrix converters is presented with the aim of predicting possible critical operating conditions. It is verified that all of the system parameters affect more or less the stability, including the delay introduced by the digital controller and the power losses. The theoretical analysis is supported by numerical simulations and experimental results carried out on a matrix converter prototype.

Speed Finite Control Set Model Predictive Control of a PMSM Fed by Matrix Converter

This paper presents a new speed finite control set model predictive control algorithm, which has been applied to a permanent-magnet synchronous motor driven by a matrix converter (MC). This method replaces the classical cascaded control scheme with a single control law that controls the motor currents and speed. Additionally, unlike classical MC modulation methods, the method allows direct control of the MC input currents. The performance of the proposed work has been verified by simulation studies and experimental results.

Automated Optimal Design of Input Filters for Direct AC/AC Matrix Converters

This paper presents a novel method to design the input filter for a direct ac/ac matrix converter using genetic algorithms (GA) optimization. The input filter for a matrix converter is a very important and critical part of the conversion structure and careful design is necessary to ensure high input power quality, compactness, and stability. The GA will optimize structure and parameters of the input filter as a function of different factors such as energy storage, weight, and volume. The effectiveness of this design method is demonstrated through a wide range of simulations using Saber and experimental results on a laboratory prototype. The same methodology could also be adapted and applied to any converter configuration such as, for example, traditional voltage source converters.

An overview of the more electrical aircraft

This article introduces the more electric aircraft concept and investigate the potential benefits of the technology for manned aircraft. Typical aircraft electrical power systems and loads are described as well as the exciting, future challenges for the aerospace industry. The importance of power electronics as an enabling technology for this step change in aircraft design are considered and examples of typical system designs are discussed.

Optimized Commissioning Method for Enhanced Vector Control of High-Power Induction Motor Drives

This paper presents a method for improving the control design for a high-power induction motor (IM) drive employing rotor-flux-based orientation. An offline genetic-algorithm routine is used to estimate the electrical and mechanical parameters of the machine using only speed transient measurements. This routine is applied to a range of operating conditions to obtain an accurate knowledge of the IM parameters as a function of the d-axis motor current id. The information acquired is then employed, together with an enhanced control design obtained by optimizing speed and current transient responses, to increase the performance of the vector control algorithm. The effectiveness of this design method is demonstrated through a wide range of simulations using Matlab-Simulink and experimental results at power levels up to 230 kW.

Identification of Induction Machine Electrical Parameters Using Genetic Algorithms Optimization

This paper introduces a new heuristic approach for identifying induction motor equivalent circuit parameters based on experimental transient measurements from a vector controlled induction motor (I.M.) drive and using an off line genetic algorithm (GA) routine with a linear machine model. The evaluation of the electrical motor parameters is achieved by minimizing the error between experimental responses (speed or current) measured on a motor drive and the respective ones obtained by a simulation model based on the same control structure as the experimental rig, but with varying electrical parameters. An accurate and fast estimation of the electrical motor parameters is so achieved. Results are verified through a comparison of speed, torque and line current responses between the experimental IM drive and a Matlab-Simulink model.

An all SiC MOSFET high performance PV converter cell

Recent studies have pointed out the benefits of using Silicon Carbide (SiC) devices in photo-voltaic power conversion. In Particular, SiC Power MOSFET technology has greatly advanced over the last years and has presently reached sufficient maturity to stimulate a concrete interest in the development of power conversion circuits based entirely on this technology, in view of the clear potential advantages it offers over alternative SiC device technologies (e.g., JFET, BJT). This paper presents a thorough characterization of an all SiC MOSFET based single-phase bi-directional switched neutral-point-clamped (BSNPC) three level inverter, in which, for the first time, SiC Power MOSFETs of different voltage ratings (1200 and 600V) are used. A parametric experimental characterization of the power cell performance is carried out, separating the effects of output power, heat-sink temperature and switching frequency and load variations by means of bespoke heat-sink design. The effect of relying exclusively on the MOSFET body-diode for inductive load current freewheeling is critically assessed against usage of an external SiC Schottky diode. The experimental results are compared with a mixed approach design, where Silicon (Si) devices are used for the lower voltage switches and SiC MOSFETs are kept for the higher voltage ones, deriving a clear indication of the superior possibilities offered by SiC Power MOSFETs for improved efficiency, power density and reliability, key aspects of power electronics technology evolution.

Comparison between back-to-back and matrix converters based on thermal stress of the switches

A comparison between a matrix converter and a back-to-back converter feeding a passive load is presented in this paper, with the aim of determining the converter topology which yields the highest output power per switches number. The comparison has been performed for different values of the output frequency. For each output frequency the load power has been increased until one of the switching devices reaches the maximum thermal stress, so defining the maximum output power of the converter. For this purpose, a simplified thermal model has been used to evaluate the junction temperature of the switches on the basis of the switch losses. An accurate computer model of both converters has been implemented taking into account the modulation laws and the real characteristics of the switching devices. Simulation results are presented showing the different behaviour of the two converters as a function of the output frequency. It has been verified that matrix converters perform better than back-to-back converters at low output frequencies.