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For the grid connection of voltage source inverters (VSIs), the power passive filters are a standard solution for grid-current harmonic attenuation. However, these types of filters may cause resonance between the inverter and the grid. Passive and active damping techniques are employed for resonance attenuation. Efficiency concerns have set active damping techniques as a promising solution for the...
Repetitive control offers an accurate current control scheme for grid-tied converters to feed high quality sinusoidal current into the grid. However, with grid frequency being treated as a constant value, conventional repetitive controller fail to produce high quality feeding current in the presence of practical time-varying grid frequency. This paper explores frequency adaptive repetitive control...
SRM presents many advantages such robustness, simple manufacturing and reliability. However, it is characterized by torque ripples and acoustic noise that are delicate and difficult to assess. In this paper, authors propose an analytical electromagnetic-mechanical model able to evaluate vibration in the stator structure of an 8/6 SRM. This model was implemented and wedged experimentally relative to...
This paper presents some results of an ultra-high-speed switched reluctance motor operating in an electric assisted turbocharger on a diesel engine. The motor controller operates without a shaft-mounted position sensor and work has been undertaken to tune the sensorless algorithm parameters and improve the control stability. A motor model has been developed to more accurately simulate the machine...
The aim of this paper is to analyze the stability of grid-connected photovoltaic (PV) generators when a large number of equally rated inverter modules is connected in parallel, as recently implemented in PV power farms. In grid-connected applications, the presence of parallel inverters results in the impedance multiplication effect, where the grid impedance seen by each inverter module is multiplied...
Part I of the study presents the importance and the analytical and numerical methods to perform a thermal- mechanical stress simulation with evenly distributed temperature for single wires. Part II of the study presents a method with thermal and mechanical conjugated simulations with unevenly distributed temperature for multiple wires and the results are compared to the structural simulation with...
The adoption of the fast-switching silicon carbide (SiC) devices in the conventional two-level voltage source converters can bring issues such as crosstalk effect, high turn-on losses, electromagnetic interference (EMI), etc. The split output converter can decouple the upper SiC MOSFET from the lower SiC MOSFET in the same phase leg with suppressed crosstalk effect, lower turn-on losses, and reduced...
An increased attention has been detected to develop smaller and lighter high voltage power converters in the range of 50V to 400V domain. The main applications for these converters are mainly focused for Power over Ethernet (PoE), LED lighting and AC adapters. This work will discuss a study of using enhancement mode gallium nitride switches to form a 50V quasi-square-wave zero-voltage-switching buck...
This paper discusses coil pressing through which stator windings are compressed at high pressures to enhance the slot fill factor of electrical machines. Deterioration of insulation in compressed windings is investigated by performing quasi-static explicit dynamics finite element simulations. The results obtained from the proposed method are further investigated experimentally to validate the durability...
The use of soft-switching techniques, interleaved topologies and silicon carbide (SiC) MOSFETs can improve the efficiency and power-density of high-power, high-voltage DC-DC converters for electric vehicle and aircraft applications. In this paper, to extend the operating range of the Snubber Assisted Zero Voltage and Zero Current Transition (SAZZ) dual-interleaved boost converter beyond its inherent...
Within the field of power converter design, the use of optimisation techniques is a popular method to ensure that the best possible design is achieved for a given objective, e.g. weight or volume reduction. However, there is currently a lack of efficient unified frameworks for optimising the system level design of converters in terms of the device, heatsink and passive component selection. This paper...
Volume and weight are mostly considered when determining more electric aircraft (MEA) power system architecture in industry. However, stability, which has a great impact on system performance, is often neglected. Constant power loads (CPLs), which take a great portion in MEA loads, have destabilizing effect. This paper compares hybrid AC/DC and HVDC architecture for MEA from the perspective of system...
Traditional high-power centralized front-end DC/DC converter can be replaced with an array of paralleled standardized DC/DC transformer (DCX) modules when load current sharing is accomplished between individual modules. In this study, an LLC resonant converter is proposed as an unregulated DCX module, which has current sharing capability. Current sharing feature is implemented by using the droop current...
In this paper the power losses of the 3-level-topology “Mixed Voltage Neutral Point Clamped (MNPC)”, also referred to as “T-Type” topology, will be analysed with SiC-MOSFET-based power modules for a variable power factor with cos(φ) = 0…1ind. The advantages of the MNPC with Silicon Carbide (SiC) semiconductors have been demonstrated in previous studies with high efficient PV-inverters. As a result,...
The increased switching losses with increasing switching frequency are the biggest concerns in designing high power density converters. This paper presents the investigation of an energy efficient DC-DC flyback converter in combination with six layered printed circuit board transformer. The recorded efficiency of the low profile transformer for the frequency range of 1–5MHz is 98% at power density...
The direct torque and flux control (DTFC) scheme is well known for its simplicity and less parameter dependency compared to the conventional current vector control scheme. It can drive an interior permanent magnet synchronous motor (IPMSM) in usual control regimes while satisfying current and voltage limits of the motor and inverter. If the characteristic current of an IPMSM is less than the rated...
In this paper the design of a linear electrical machine for use with a free-piston engine will be discussed. Three conventional permanent magnet machines are compared to a flux switching and modulated pole machine. Each of the topologies is optimised to give a specific force whilst adhering to a limit on the mass of the moving component. Using simple vector analysis, it is shown that machine power...
This paper presents a high-fidelity Permanent Magnet Synchronous Motors model suitable for implementation in real-time Hardware-in-the-loop development and testing of motor control algorithms. The accurate model, based on capturing the variation of flux linkages with currents and rotor position obtained by finite element analyses (FEA), is capable of accounting for the nonlinearities due to saturation,...
This work presents the analysis of a radial plus VSC-HVDC scheme in terms of its impact on AC and DC system dynamics. This study uses the classical two-area system with modified demand as an onshore AC grid. Full converter wind power plants (WPPs) are connected to the main grid through two point-to-point VSC-HVDC links, which are connected offshore through an AC cable to form a ‘radial plus’ strategy...
The increasing number of power electronic inverters connected to the utility grid means their synchronization to the utility grid plays an increasingly key role. Typically a phase-locked loop (PLL) is used, however limited information is still only available on PLLs in the public domain comparing them for power system applications. This paper presents quantified analyses and comparisons of the main...
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