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Multilevel Modular Cascade Converters (MMCC) can be used to provide higher effective switching frequencies and reduce harmonic distortion in classical converter problems such as BESS and STATCOM. To successfully implement a MMCC in a STATCOM application it is necessary to balance dc-link voltages of the individual modules and track a reference output current. This work presents master and individual...
Multi-port dc-ac and dc-dc converters are of great interest for applications where electricity is generated through a variety of energy sources and where energy storage systems are required. In this paper, a three-port, dc-dc-ac Solid State Transformer (SST) is presented that can control the magnitude and direction of power transfer between a battery, a dc bus and the ac grid. The proposed SST features...
Regularly sampled pulse width modulation (PWM) has been a mainstay of the power electronics community since the advent of digital controllers. In this form of PWM the modulating signal is sampled only at either the peaks and/or the troughs of the triangular carrier waveform, then held constant until the next sampling instant, which allows ample time for the calculation of switching instants. Unfortunately,...
This paper proposes the development of a new digital pulse width modulation (PWM) scheme for aplication to both single phase and multiphase voltage regulation modules (VRMs), which are used as processor power supplies. A comparative analysis of this novel phase accumulator based PWM generation technique is presented with the traditionally used counter based PWM approach for synchronous buck converter...
A frequency modulation scheme is proposed for a Capacitor-Inductor-Inductor-Capacitor (CLLC) Resonant Dual Active Bridge (RDAB) that relies on dynamic retuning of the resonant capacitors to the switching frequency as it is modulated. The proposed modulation scheme greatly reduces the circulating reactive currents in the High Frequency Link (HFL) by operating at a range of fixed discrete switching...
Aurizon, Australia's largest freight railway operator, is investigating the use of Rail Power Conditioner (RPC) technology for load balancing, reactive power compensation and harmonic filtering. The new technology has the capability of replacing Static VAr Compensators (SVC) and Harmonic Filters, and is expected to have a significant impact on the overall costs of railway electrification. This paper...
Distributed renewable energy has become a significant contender in the supply of power in the distribution network in Queensland and throughout the world. As the cost of battery storage falls, distribution utilities turn their attention to the impacts of battery storage and other storage technologies on the low voltage (LV) network. With access to detailed residential energy usage data, Energex's...
Aurizon, Australia's largest rail freight operator, is introducing the Static Frequency Converter (SFC) technology into its electric railway network as part of the Bauhinia Electrification Project. The introduction of SFCs has significant implications on the protection systems of the 50kV traction network. The traditional distance protection calculation method does not work in this configuration because...
An alternative approach to digital PWM generation uses an accumulator rather than a counter to generate the carrier. This offers several advantages. The resolution and gain of the pulse width modulator remain constant regardless of the module clock frequency and PWM output frequency. The PWM resolution also becomes fixed at the register width. Even at high PWM frequencies, the resolution remains high...
Major advances in power electronics during recent years have prompted considerable interest within the traction community. The capability of new technologies to reduce the AC railway networks' effect on power quality and improve their supply efficiency is expected to significantly decrease the cost of electric rail supply systems. Of particular interest are Static Frequency Converter (SFC), Rail Power...
Proposed in this paper is a low-cost, half-duplex optical communication bus for control signal isolation in modular or multilevel power electronic converters. The concept is inspired by the Local Interconnect Network (LIN) serial network protocol as used in the automotive industry. The proposed communications bus utilises readily available optical transceivers and is suitable for use with low-cost...
Piezoelectric ultrasound transducers are commonly used to convert mechanical energy to electrical energy and vice versa. The transducer performance is highly affected by the frequency at which it is excited. If excitation frequency and main resonant frequency match, transducers can deliver maximum power. However, the problem is that main resonant frequency changes in real time operation resulting...
The spectral energy associated with the carrier and sidebands of naturally sampled carrier based PWM can be spread by randomising the carrier (switch) half-period Tc = 1/2fc. So long as the switch duty cycle each period still correctly reflects the value of the modulating fundamental waveform as sampled during that switch period, then the fundamental component will remain undistorted. Natural sampling...
Frequency Domain Spectroscopy (FDS) is one of the major techniques used for determining the condition of the cellulose based paper and pressboard components in large oil/paper insulated power transformers. This technique typically makes use of a sinusoidal voltage source swept from 0.1 mHz to 1 kHz. The excitation test voltage source used must meet certain characteristics, such as high output voltage,...
This paper proposes a linear state-space model for a phase-controlled resonant dual active bridge with a tuned capacitor–inductor–inductor–capacitor network. The proposed model is useful for fast simulation and for the estimation of state variables under large signal variation. The model is also useful for control design because the slow changing dynamics of the dq variables are relatively easy to...
A nine level modular multilevel cascade converter (MMCC) based on four full bridge cells is shown driving a piezoelectric ultrasonic transducer at 71 and 39 kHz, in simulation and experimentally. The modular cells are small stackable PCBs, each with two fully integrated surface mount 22 V, 40 A MOSFET half-bridge converters, and include all control signal and power isolation. In this work, the bridges...
Integrating Photovoltaic (PV) systems with battery energy storage in the distribution network will be essential to allow for continued uptake of domestic PV system installations. With increasing concerns regarding environmental and climate change issues, incorporating sources of renewable energy into power networks across the world will be key for a sustainable future. Australia is well placed to...
Double-pulse tests are commonly used as a method for assessing the switching performance of power semiconductor switches in a clamped inductive switching application. Data generated from these tests are typically in the form of sampled waveform data captured using an oscilloscope. In cases where it is of interest to explore a multi-dimensional parameter space and corresponding result space it is necessary...
Conventional voltage driven gate drive circuits utilise a resistor to control the switching speed of power MOS-FETs. The gate resistance is adjusted to provide controlled rate of change of load current and voltage. The cascode gate drive configuration has been proposed as an alternative to the conventional resistor-fed gate drive circuit. While cascode drive is broadly understood in the literature...
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