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This paper presents the use of a three-phase switched capacitor converter to dimming of power light-emitting diodes (LEDs). The converter does not utilize electrolytic capacitors, providing a high useful lifetime. In addition, it can stabilize the output current in open loop control, without needing current sensors, which reduces the project cost. Moreover, the output power is proportional to the...
Grid-connected current source inverter (CSI) employs CL-filter to meet the harmonic limitations set by IEEE 519-1992 and IEEE 1547-2008. However, parameter design for the CL-filter is rarely studied and no formalized approaches are followed. Therefore, this paper identifies the limitations in designing CL-filters for a single-phase grid-connected CSI and presents a complete design procedure which...
This paper is focused on the influence combinations of the dead time duration and switching frequency on the drawn current from the grid by voltage-source active rectifiers. Newly the various definitions of the total harmonic distortion of the current are used. According to the EU standard the total harmonic distortion of the current is calculated up to the 50th harmonic; this definition of the total...
This paper introduces advanced power-electronic converter topologies for Electric Vehicles (EVs) using a four-phase DC/DC interleaved boost converter (FP-IBC) and a five-level T-type DC/AC multilevel converter. A comparison between the proposed topologies and other converter topologies is performed and discussed. The simulation results are analysed to evaluate the converters based on power loss calculations...
This paper presents a novel zero-crossing point detection method for boundary current mode PFC converter. In the conventional boundary current mode, the zero-crossing point is detected by observing the inductor voltage. When the digital controller is used in the conventional method, the detection of the zero-crossing point is delayed due to the delay time caused by the processing of DSP. And the detection...
This paper presents a random frequency hopping with triangular ramp control for harmonic reductions in a dc-dc converter. The relationship between “the sawtooth and triangular ramp signals” and the inductor current is analyzed, and the two ramp signals are implemented into the converter to compare the variation of output voltage. When the switching frequency hops, using triangular ramp keeps the small...
Nowadays, there is a rapid development of devices of uninterruptible power supply (UPS) in communications. Inverter is one of the important parts in the UPS and its producing of current harmonics negatively affects the operation quality of communication devices. Therefore, reduction of current harmonics in the UPSs to achieve the stringent standards is one of the priority tasks of the inverters. Increasing...
In order to further cut down the cost of filter for grid-connected pulsewidth modulation (PWM) converter under the more and more stringent grid code, a new kind of high-order filter, named LCL-LC filter, is presented in this paper. The resonant frequency characteristics of the filter are analyzed, and a parameter design method on the base of the characteristics is also proposed in the paper. The proposed...
In this paper, reliability-oriented switching frequency analysis for Modular Multilevel Converter is investigated. In the medium voltage and high voltage direct current applications, the switching frequency should be low enough to avoid the converter from high switching power losses. In the other hand, choosing the switching frequency very low will impose higher ripple over the capacitor and will...
Static power converters have widespread applications, such as ground power units (GPU) for airplanes. A modified static ground power unit based on 5-level Active Natural Point Clamped (5L-ANPC) multilevel converter is proposed in this paper. A new LS-PSC-PWM switching method for the 5L-ANPC converter is defined in this paper. The provided THD value of proposed converter will be less than those the...
In a hybrid cascaded multilevel converter subject to different DC-link voltage levels among cascaded cells, should conventional carrier phase-shifting pulse-width modulation be applied, it will fail to multiply the equivalent switching frequency of the overall output voltage. As a consequence, this makes it more difficult to design the output filter and limits the overall output bandwidth. Based on...
This paper investigates various random PWM (RPWM) techniques for conventional two-level inverter-fed traction drives and proposes a discrete RPWM technique for acoustic noise reduction. The proposed RPWM technique randomizes within a set of predefined switching frequencies compared with the continuous nature of randomization in conventional RPWM techniques. The proposed method was compared with conventional...
The output power regulation and transfer efficiency are key issues in inductively coupled power transfer system (ICPT) systems. The harmonic based phase shift control (HPSC) is an effective method to improve system efficiency. However, due to the high frequency and harmonic components of the inverter output current within this method, general closed-loop control is not suitable. Meanwhile, in inductively...
Soft magnetic composite (SMC) is considered as an alternative solution for core materials of inductors used in LCL filters in power converter applications. Performance of SMC inductors in damping a range of harmonics caused by voltage switching is an interesting topic. The method used in this paper is to test the inductors together with a 70 kW PWM inverter to examine the filtering effects for different...
Electric vehicles rely on efficient charging techniques to maximize battery performance, efficiency and lifetime. Most EV on-board chargers are supplied from single phase AC mains, and contain 2nd order mains frequency harmonic in the battery current. This harmonic current incurs extra loss in the battery, increases battery temperature, and hence reduces charging efficiency and battery lifetime. Conventional...
The capacitor voltage drift problem in Modular Multilevel Converter (MMC) system has been widely discussed in the past. It is well known that sometimes the capacitor voltages are balanced, without any active controls. However, due to the uncertainty and lack of theoretical explanations, active capacitor voltage controls are typically preferred for real applications, and the voltage balancing/drift...
This paper proposes an isolated single switch dc-dc converter suited to a high frequency switching operation. The impedance seen at the drain to source node of the switch is mainly designed for achieving zero voltage switching (ZVS) operation and reducing the voltage stress across the switch device. In the proposed converter, leakage inductances of the transformer are integrated to the resonant network...
Three-phase single-switch boost PFC converter operates in discontinuous current mode (DCM) to achieve PFC. If the duty cycle is constant in a line cycle, the average value of the inductor current in a line cycle is not sinusoidal. The PF is low and the input current contains rich 5th and 7th harmonics. Variable switching frequency control can reduce the input current harmonic distortion. However,...
This paper presents a novel design method for class E dc-dc converter and a control scheme capable of operating in a wide load range. The class E converter is suitable for several-MHz switching frequency; however, the conventional design has two drawbacks: high voltage stress on the switch (theoretically about 3.6 times the input voltage), and a large input inductor. Here we propose the design scheme...
A multilevel boost PFC (Power Factor Correction) rectifier is presented in this paper controlled by cascaded controller and multicarrier pulse width modulation technique. The presented topology has less active semiconductor switches compared to similar ones reducing switching losses as well as the number of required gate drives that would shrink manufactured box significantly. A simple controller...
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