Power conversion for a novel AC/DC aircraft electrical distribution system

This paper proposes a novel and compact AC/DC electrical distribution system for new generation aircraft. In these new aircraft power systems, all loads are fed by two dc bus systems: at 28V and at +/-270V. The electrical distribution system, whose design and implementation are described in this paper, has only one primary AC source (360-900Hz at 230V) with all the required dc voltage levels being derived from this source. This solution enables elimination of the complex mechanical coupling apparatus currently used, for fixed frequency AC systems, to maintain the generator speed at constant level while the engines operate at variable speed. Under the proposed solution, all conversion stages needed to generate the various output voltage levels are implemented using power converters assembled in one unit. Each converter has a current control loop in order to regulate the output current even during output line short circuits and also to limit the inrush current to the circuit at turn-on. To prove the concept a 5 kW prototype was designed and tested, and demonstrated to meet all the specifications within relevant standards regarding input and output power quality

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 (FCS-MPC) algorithm which has been applied to a Permanent Magnet Synchronous Motor (PMSM) 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

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

Fixed frequency finite-state model predictive control for indirect matrix converters with optimal switching pattern

Finite States Model Predictive Control (MPC) has been recently applied to several converters topologies for the many advantages it can provide such as fast dynamics, multi-target control capabilities, easy implementation on digital control board and capability of including constraints in the control law. However, its variable switching frequency and lower steady state waveform quality, with respect to standard control plus modulator systems, represents a limitation to its applicability. Modulated Model Predictive Control (M²PC) combines all the advantages of the simple concept of MPC together with the fixed switching frequency characteristic of PWM algorithms. In particular this work focuses on the Indirect Matrix Converter (IMC), where the tight coupling between rectifier stage and inverter stage has to be taken into account in the M²PC design. This paper proposes an M²PC solution, suitable for IMC, with an optimal switching pattern to emulate the desired waveform quality features of Space Vector Modulation (SVM). In the optimal pattern, the switching sequences of the rectifier stage and inverter stage are rearranged in order to always achieve zero-current switching on the rectifier stage, thus simplifying its commutation strategy. In addition, the optimal pattern enables M²PC to produce sinusoidal source current, sinusoidal output current and maintain all desirable characteristics of MPC

Modulated predictive control for indirect matrix converter

Finite State Model Predictive Control (MPC) has been recently applied to several converter topologies as it can provide many advantages over other MPC techniques. The advantages of MPC include fast dynamics, multi-target control capability and relatively easy implementation on digital control platforms. However, its inherent variable switching frequency and lower steady state waveform quality, with respect to standard control which includes an appropriate modulation technique, represent a limitation to its applicability. Modulated Model Predictive Control (M2PC) combines all the advantages of MPC with the fixed switching frequency characteristic of PWM algorithms. The work presented in this paper focuses on the Indirect Matrix Converter (IMC), where the tight coupling between rectifier stage and inverter stage has to be taken into account in the M2PC design. This paper proposes an M2PC solution, suitable for IMC, with a switching pattern which emulates the desired waveform quality features of Space Vector Modulation (SVM) for matrix converters. The switching sequences of the rectifier stage and inverter stage are rearranged in order to always achieve zero-current switching on the rectifier stage, thus simplifying the current commutation strategy

Experimental efficiency comparison between a direct matrix converter and an indirect matrix converter based on efficiency using Si IGBT and SiC MOSFETs

This paper presents an experimental efficiency comparison study between two different direct AC-AC converter topologies: a direct matrix converter (DMC) and an indirect matrix converter (IMC). The evaluation is performed under variable load conditions using both discrete Silicon (Si) IGBTs and Silicon Carbide (SiC) MOSFETs working at power levels up to 9 kW. Each loss measurement is carried out using two power analyzers: one placed at the input and one at the output of the converter under study. To facilitate this measurement an output filter was necessary in addition to the normal input filter. Both converters are modulated the same traditional symmetrical space vector approach and feature an identical input/output filter design

A Single Phase Hybrid Multiport Microinverter for Photovoltaic Energy Controlled by Exact Linearization

Solar energy can be captured by Photovoltaics (PV) and converted into electrical power. This electrical power can then be connected to grids by power electronic converters, which can also operate the PV panels at around their maximum power point (MPP), maximizing the harvested energy. When the PV panels are connected in an array, the partial shading effect generates a distortion of the power curve can result in a power loss since tracking algorithms might not be able to detect the MPP. To solve this issue microinverters have been proposed, with a small power electronic converter being connected to each PV panel, this arrangement enables independence for maximum power point tracking and electrical isolation. This paper presents a double output multiport microinverter capable of feeding DC and AC loads or providing connection to a single-phase AC grid and energy storage. The proposed structure can be operated in grid-connected and islanded modes. This paper describes the microinverter controlled with the exact linearization technique on both the DC and AC sides, obtaining a lineal transfer function representation of the nonlinear and coupled power electronic converters. The operation of the proposed topology and its control strategy is validated using a laboratory proof-of-concept prototype

Research and Realization of High-Power Medium-Voltage Active Rectifier Concepts for Future Hybrid-Electric Aircraft Generation

This paper describes the research and development of a 3kV active rectifier for a 4MW aerospace generator drive system demonstrator. The converter is fed by a multi-phase high speed/high frequency, permanent magnet generator. The main aim of the work is to demonstrate for the first time the feasibility of a MW-class generator system meeting future hybrid-electric propulsion requirements. A concept with multiple and isolated three-phase systems feeding different power buses is proposed to meet the availability requirements. Multiple converters (one for each three-phase system) are connected in series and/or in parallel to achieve the rated power and DC link voltage. This paper describes the key design concepts and the development and testing of the converter to meet the challenging application requirements. Reduced power tests are carried out on a full scale 4 MW converter prototype, validating the proposed design. The work represents a step forward in terms of voltage, power, and output frequency, with respect to the state of the art