Design challenges in the use of silicon carbide JFETs in matrix converter applications

This paper investigates some of the challenges en¬countered during the implementation of a Silicon Carbide JFET matrix converter which has been designed to meet a specific power density of 20kW/litre with forced air cooling. After a brief introduction to the main features of the hardware implementation of the power converter, an insight into the control strategy and controller platform adopted is given with a particular attention to the issues relating to the high switching frequencies on the controller requirements and the performance implications of the gate drive circuitry. An analysis of the results which show the effects of gate driver and controller induced commutation time limitations on the output waveform quality is presented. Wide bandgap semiconductor devices offer the power electronic engineer new opportunities for high speed, high efficiency designs but these devices cannot be used as a simple like for like replacements and as such the whole converter system needs to be looked at

A four-legs matrix converter ground power unit with repetitive voltage control

In this paper, a four-leg matrix converter is proposed as the power conversion core for aircraft ground power unit (GPU) applications. This structure allows easy management of unbalanced and nonlinear loads with minimal disruption of the power supply operation. A hybrid repetitive-traditional control system is proposed to regulate the output voltage of the GPU. This solution reduces the steady-state tracking error, maintaining fast dynamic characteristics, and increases the stability of the converter compared to conventional approaches. Simulations and experimental results from a 7.5-KW converter prototype are presented to verify the operation of the proposed configuration and to prove the effectiveness of the solution

Direct predictive current-error vector control for a direct matrix converter

This paper proposes a novel control strategy for matrix converters which is coined “Direct Predictive Current-error Vector Control”. The proposed control method retains the advantageous features of both a modulation scheme and of a predictive based controller. The result is a controller that is capable of good dynamic performance and steady state response with fixed switching frequency operation. Control of load and input currents of a direct matrix converter using the proposed method is demonstrated in this paper by simulation and experimental results

Novel silicon carbide integrated power module for EV application

The successful penetration of Electric Vehicles (EVs) into the global automotive markets requires the developments of cost effective, high performance and high integration power electronic systems. The present work is concerned with the structural integration of power electronic converters to meet targets for increased power density, improved electrical performance and reduced cost without compromising thermal performance or reliability for EV applications. In particular, a SiC power module to integrate multiple functional elements, i.e. semiconductor devices, DC-link capacitors, output filters, current sensing, and gate driver within a single enclosure sharing a common cooling circuit has been designed and fabricated. Electrical test results showed very smooth waveforms of the outputs, verifying the high frequency switching capacity of the fabricated power module

Design of a high-force-density tubular motor

This paper deals with the design, construction and experimental verification of a high force density, tubular, linear, permanent magnet motor, driven from a high power density matrix converter for an aerospace application. The work also describes the implementation and experimental verification of a novel, thermal management technique for the phase windings of electrical machines. The technique introduces a higher thermal conductivity path between the centre of the slot and the cooling arrangement, thus increasing the heat flow away from the slot centre. An introduction to the design of the motor is first given, after which an introduction to the technique is presented. A study of how the implementation of the technique affects motor performance is then presented. A detailed overview of the construction aspects is highlighted and finally, experimental validation is used to illustrate the comparison between the predicted results and the measured results, obtained from an instrumented, test rig

Matrix converter open circuit fault diagnosis with asymmetric one zero SVM

An open-circuit fault detection and diagnosis strategy for a direct matrix converter is proposed in this paper. The current recirculating path during an open circuit condition is considered in detail with the aim of contributing more expert knowledge to the fault detection system for matrix converter. Simulation results are presented demonstrate the open circuit fault behavior of matrix converter. This expert knowledge is extremely important for the fault detection system to avoid false diagnosis. This work leads to the presentation of a reliable and fast fault detector for the Matrix Converter

Matrix converter open circuit fault behavior analysis and diagnosis with a model predictive control strategy

A novel fast and reliable open circuit fault diagnosis strategy for a Matrix Converter with a Finite Control Set Model Predictive Control strategy is proposed in this paper. Current sensors are located ahead of the clamp circuit to measure the output currents in order to improve the speed of fault diagnosis. In addition, the current recirculating path during a single open circuit switch fault condition is given in detail with the aim of contributing more expert knowledge to the fault diagnosis. The proposed fault diagnosis method is applicable over the whole range of modulation index

Experimental comparison of a matrix converter using Si IGBT and SiC MOSFETs

This paper presents an analytical and experimental comparison between comparable Silicon (Si) IGBTs and Silicon Carbide (SiC) MOSFETS when used in a direct AC/AC matrix converter circuit. The switching performance of the two devices is analysed and the efficiency / losses measured in order to develop a loss model which will help engineers to design and develop matrix converter circuits using these types of devices. Particular attention is given in the paper to the discrepancies found between the data-sheet values and the measured data. The EMI performance of the two matrix converters is also determined and the implication of using high speed devices from both an EMI and an efficiency point of view is formulated together with an improved input filter design

Reduction of output common mode voltage using a novel SVM implementation in matrix converters for improved motor lifetime

This paper presents the study of an alternative Space Vector Modulation (SVM) implementation for Matrix Converters (MC) which reduces the output Common Mode (CM) voltage. The strategy is based on replacing the MC zero vectors by the rotating ones. In doing this, the CM voltage can be reduced which in-turn reduces the CM leakage current. By reducing the CM current, which flows inside the motor through the bearings and windings, the Induction Motor (IM) deterioration can be slowed down. The paper describes the SVM pattern and analyses the CM voltage and the leakage current paths. Simulation and experimental results based on a MC-IM drive are provided to corroborate the presented approach

Open circuit fault detection and diagnosis in matrix converters

With the increased use of power electronics in aerospace, automotive, industrial, and energy generation sectors, the demand for highly reliable and power dense solutions has increased. Matrix converters become attractive when taking into account demands for high reliability and high power density. With their lack of large bulky DC-link capacitors, high power densities are possible with the capability to operate with high ambient temperatures. When a power converter needs high reliability, under tight weight and volume constraints, it is often not possible to have an entirely redundant system. Taking into account these constraints it is desirable that the power converter continue to operate even under faulty conditions, albeit with diminished performance in some regard. This paper presents an open circuit switch fault detection and diagnosis system for matrix converters, which has been experimentally validated. The presented system requires no load models, averaging windows or additional sensors, this makes the proposed method fast and low cost