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Multilevel inverters have been widely used in medium and high voltage applications. Selective harmonics elimination for the staircase voltage waveform generated by multilevel inverters has been studied extensively in the last decade. Most published methods on this topic aimed at solving high-order multi-variable polynomial equation groups derived from Fourier series expansion. A totally different...
Being compared with conventional fluorescent lamps, the cold cathode fluorescent lamps (CCFL) have more compact size, longer lifetime and higher light efficiency. Therefore, they have been widely used as illuminating source and background lighting in LCD panel and notebook computers. However, there is lack of a suitable CCFL model which can be used for ballast designer to apply in their designing...
A lumped equivalent circuit model for the radial mode piezoelectric transformer is presented, based on a one-dimensional analysis of the radial vibration mode and the constitutive piezoelectric equations. The model allows each of the components in the piezoelectric transformer equivalent circuit to be calculated from the appropriate material properties and device dimensions, thereby facilitating the...
Among the paralleled UPS control strategies, output droop method and average power control method need to calculate UPS output active and reactive powers accurately for control of the phase (frequency) and amplitude of output voltage. In light or no load conditions, active circulation currents may cause high DC voltages which will damage the machine. This paper suggests using the UPS output filter...
This paper discusses and analyses the parallel operation of uninterruptible power supplies (UPS) units when loaded through long wiring cables having non-negligible inductance and resistance. This scenario is often encountered in practice, as the UPS power supplies are often located far from the load they are actually powering. The analysis demonstrates how long cable connections between the power...
This study presents a permanent magnetic linear generator based system for ocean wave energy harvesting applications. The use of linear generator as energy converter enables a direct coupling of the motion of the buoy to the energy harvesting system. Mathematical model governing the system is presented; frequency domain analysis reveals that conversion rate varies with respect to load resistance....
This paper presents a controller with duty-cycle dynamic distribution within parallel-connected PFC converters based on average-current control strategy, which can distribute the control duty-cycle automatically for each parallel-connected PFC converter to realize current balance by the difference from its reference current, and it can decrease and even eliminate the disturbance resulted by current-balancing...
Islanding detection and anti-islanding protection are the essential functions of the gird-connected inverter in DG systems. This paper focuses on the non-detection zone (NDZ) with passive islanding detection method for the DG system with the current control scheme. The parameters of the point of common coupling such as the voltage amplitude and frequency are studied through mathematical derivation...
Flyback switched-mode converters are among the most popular in the low-power range, due to their simplicity and low cost. They are especially popular in multi-output applications, due to the low parts count-one diode and capacitor per output. They would be even more popular if the output regulation were better. This paper reviews the common techniques to tighten the output regulation, and summarizes...
This paper presents the control structure for a novel three-port converter topology. This topology has the advantage of low switch count, high power density, high efficiency, so it is a valuable choice for space applications. The three port converter for space application interfaces one solar panel input port, one bi-directional battery port and an isolated output port. Lithium-Ion battery charge...
Batteries are a common element used in many electronic applications. Therefore, the analysis and simulation of these applications requires a battery model in order to validate the behavior of the whole system. Since batteries are based on different technologies, a modeling approach valid for any technology is a potential good alternative. Since there are similarities among the different technologies,...
Capacitor voltage oriented PI control is implemented to control the phase voltage of a customer-end single-phase inverter in a low-voltage DC (LVDC) distribution system. Synchronous dq-frame is used to control the phase voltage to avoid the drawbacks of the PI control, such as possible steady-state error. In the paper the controller equations are derived from the system equations and then the controllers...
When a power factor corrector (PFC) is designed with a fast output-voltage feedback loop, the study of the power stage varies in comparison with the one carried out with a slow output-voltage feedback loop. This is a consequence of the voltage ripple that appears in the control signal. The static behaviour of a PFC with a fast output-voltage feedback loop is studied in this paper using two parameters:...
A novel ZVZCS L2C-Type parallel resonant converter is presented in this paper. This converter, compared with the Type-4 LLC converter, narrows the switching frequency deviation under wide input voltage range applications, while maintaining all soft-switching advantages as ZVS for primary switches and ZCS for output rectifiers, both of which eases design for input EMI filter. In addition, the proposed...
This paper presents a family of four-quadrant dc-dc converters with minimal number of switches and passive devices. These converters employ a Z-source or a quasi-Z-source network with two active switches to provide four quadrant operation which means bipolar output voltage and bidirectional current operation. Bipolar output operation can also be realized by using one active switch and a diode. They...
This paper presents a new PWM method using a virtual DC-link voltage concept for reducing output current ripples. Matrix converter is interfaced with three phase AC voltage source. And the AC source makes three different level virtual DC-link voltages. In this paper, a generalized PWM method is proposed to use these three virtual DC-link voltages. In the case of using higher two line to line voltage...
This paper proposes a three-phase, two-switch, buck converter that can operate with input power factor correction. The key features of the proposed converter are that a switch in it can operate with almost half the voltage stress of that in the standard three-phase, single-switch buck converter and with less current stress. In the paper, the operation of the converter is discussed and a detailed mathematical...
This paper presents a dynamic model of the active front-end (AFE) converter under the synchronous reference frame. Transfer functions of the closed-loop control based on this dynamic model are verified experimentally in the frequency domain. Bode plots of these transfer functions are given to validate this synchronous frame-based dynamic model. Based on these results, this paper presents the control...
This paper proposes a set of sequence-decoupled resonant controllers constructed with an easy-to-implement structure. It shows that either positive-sequence or negative-sequence components of three-phase unbalanced AC signals can be regulated individually in the stationary frame, while conventional and widely used resonant controllers cannot separately cope with these two sequences. Consequently,...
The concept of stator flux orientation control of induction motor (IM) based on the optimal regulator theory has been introduced in the literature. In this paper, the idea is expanded to improve the performance at low speeds by proposing programmable low-pass filter (LPF) for flux vector synthesis. The developed control structure provides high-quality signal for the stator frequency. This signal is...
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