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Models of converters based on averaging have been used widely with numerous benefits. Multifrequency averaging (MFA) model can predict both the fundamental and switching behavior of converters and has the faster simulation run times associated with average-value models. Third harmonic injection is commonly used in the modulation signal for three-phase inverters to increase the inverter maximum output...
This paper compares three possible linear motor topologies for an electromagnetic launch system to assist civil aircraft take-off. Assisted launch of civil aircraft has the potential of reducing the required runway length, reducing noise and emissions near airports and improving overall aircraft efficiency through reducing engine thrust requirements. A comparison is made of practical designs of a...
A new bidirectional multilevel converter topology called Hybrid Multilevel Converter (HMC) suitable for high power AC/AC applications is presented. It is based on cascaded connection of multiple half-bridge submodules in addition to nine thyristor-based low-frequency and soft-switched unfolders in a three-phase version. Compared with a conventional modular multilevel converter (MMC), HMC requires...
In this paper, a dual-channel isolated three-phase magnetically integrated chargers (MICs) are presented for plugin electric vehicles. The key is to apply and operate two interleaved power charging circuits, each of which is composed of one dual-active-bridge (DAB) isolated converter and one three-phase grid inverter. The proposed configuration not only offers isolated charging but also provides modular...
The cogging torque is usually very sensitive to the manufacturing tolerances during machine mass production, and this paper investigates the different sensitivities between interior permanent magnet (IPM) machines with different slot/pole number combinations. Exemplified by two typical combinations, i.e. 12-slot/8-pole and 12-slot/10-pole designs, the fundamental performance is firstly analyzed under...
Single-phase traction loads generate negative sequence currents, reactive current and harmonics to the power grid. Modular multilevel converter (MMC) is a better alternative to implement railway power conditioner (RPC), which is connected to 25 kV supply system. A MMC with delta configuration is fit for controlling negative-sequence current because circulating currents across delta-connected clusters...
In this paper, the zero sequence circulating current in open winding (OW) permanent magnet synchronous machine (OW-PMSM) drives with common DC bus is systematically analysed for the first time. It is revealed that the zero sequence circulating current is affected by zero sequence back electromotive force (EMF), cross coupling voltages in zero sequence, from the machine side, pulse width modulation...
Due to the simplicity and flexibility of the structure of the Second-Order Generalized Integrator based Quadrature Signal Generator (SOGI-QSG), it has been widely used over the past decade for many applications such as frequency estimation, grid synchronization, and harmonic extraction. However, the SOGI-QSG will produce errors when its input signal contains a dc component or harmonic components with...
With the increasing penetration of nonlinear loads into distribution system, stable operation of power distribution system suffers challenge by harmonic voltage propagation and resonance amplification which is also known as whack-a-mole phenomenon. However, until now this phenomenon has not been well investigated and discussed. This paper starts from theoretical analysis of harmonic propagation and...
This paper presents a multilevel universal active power filter (UAPF) topology with nine legs. The proposed system is a combination of two series and one shunt active power filters with a connection series-shunt-series. It is suitable to improve the harmonic distortion in the grid currents and a voltage compensation. The filter is composed of three three-phase converters resulting in nine legs sharing...
In recent years, permanent magnet (PM) vernier machines have gained more and more attentions due to their high torque density and simple mechanical structure. However, vernier PM machines with lap windings always suffer from long end winding length, and regular non-overlapping winding may result in torque reduction for PM vernier (PMV) machines. In this paper, an advanced PM vernier (APMV) machine...
Grid integration testing of inverter-coupled renewable energy technologies is an essential step in the qualification of renewable energy and energy storage systems to ensure the stability of the power system. New types of devices must be thoroughly tested and validated for compliance with relevant grid codes and interconnection requirements. For this purpose, highly specialized custom-made testing...
This paper proposes a novel control method for harmonic power sharing in an islanded microgrid, without employing any control interconnections between the distributed generation (DG) units. The fundamental real and reactive power is shared by implementing conventional P-f and Q-V droop control. A virtual negative output impedance at harmonic frequency is introduced to control the distribution of harmonic...
A novel, genetic-algorithm based, design method of the passive filter-based phase shifting transformers is presented. The method improves the reliability, effectiveness, and accuracy of the filter. The filter is employed in an interphase power controller (IPC), a FACTS device unique in its power-transmitting properties. The paper demonstrates how the implementation of the proposed filter in the IPC...
In the inverter-interfaced AC microgrid (IIAM), when a short-circuit fault occurs at the distribution line, the output fault current of inverter is commonly limited to two times over its rated current due to the limited overcurrent capacity of power electronic device. Therefore, the conventional overcurrent protection principle cannot be applied to IIAM. Aiming at addressing this issue, a new protection...
This paper proposes a novel seamless transfer control strategy of three-phase grid-connected inverter between grid-connected (GC) and stand-alone (SA) modes which can cover from no load to full load, even in non linear (NL) loads. The three-phase grid-connected inverter which uses in distributed generation (DG) system can be operated in both GC and SA control modes, especially for energy storage systems...
In high-speed permanent-magnet synchronous machines (PMSMs), the permanent magnets (PMs) are usually retained by high strength sleeves. Metallic sleeves are preferred in some cases where a high rotor stiffness is required. However, high frequency time and spatial harmonics of the air-gap field would induce considerable eddy-current losses in the conductive sleeve, and thus exposing the PMs to risk...
Several methods have been proposed to measure the speed of an induction machine without the need for external speed transducers. These sensorless methods typically use observers, require injected signals, or are dependent on the detecting a specific harmonic. This paper investigates using neural networks to identify the speed of a machine using a range of harmonics without specific knowledge of machine...
Induction motor rotor designs are investigated in this paper to reduce secondary winding harmonic losses in hybrid electric vehicle (HEV) applications. The induction motor is more and more popular to use for the traction drive, but its' secondary winding harmonic losses are significantly higher than the usual when having high frequency and high power density in the HEV application. Thus, the major...
This paper proposes a variable time step controller with synchronous PWM. Since a frequency modulation index is low in an ultra-high speed or high power drive system, the modulated voltage by a fixed time step control includes large harmonic components. The optimal PWM method is one of the solution to minimize the harmonic components, but it needs many offline calculations and its structure is complicated...
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