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This paper shows an innovative improvement of the constant on time (COT) control of transition mode boost PFC. The proposed control method employs a minimum current comparator to improve the harmonic distortion and power factor of the converter while maintaining the same complexity of the constant on time control. An overview and the enhancements of this method are presented in comparison to the standard...
“Peak Current Mode Control” (CPM) is usually implemented in analogue and brings the advantage of cycle by cycle protection, higher bandwidth rejection of input voltage disturbance or equivalently increases a converter's input impedance. “Average Current Mode Control” (ACM) allows inductor current control to a “true average” and will facilitate an accurate current limit loop or Power Factor Correction...
This paper proposes a new topology for a pulse width modulation (PWM) rectifier which can achieves both sinusoidal input current on the ac side and ripple power decoupling on the DC side without additional switches. The AC inductor of the conventional H-bridge circuit is divided into two parts and only an auxiliary decoupling capacitor is added in the proposed circuit. Control scheme is also proposed...
Single-phase AC/DC or DC/AC systems inherently subject to harmonic disturbance which is caused by the well-known double line frequency ripple power. This issue can be eased through the installation of bulky electrolytic capacitors in the dc-link, but such passive filtering approach may inevitably lead to low power density and limited system lifetime. An alternative approach is to use active power...
This paper presents a high efficiency, continuous conduction mode (CCM), zero voltage switching (ZVS) bridgeless AC-DC power-factor-correction (PFC) converter for neighborhood electric vehicle (NEV) battery charging. The converter operates in both pulse-width-modulation (PWM) mode and resonant mode each switching cycle and utilizes standard average-current-mode control. This new modulation technique...
This paper presents a GaN Transistor based 90W ac/dc adapter with a Buck-PFC stage and an isolated Quasi-Switched-Capacitor (QSC) dc/dc stage. In the dc/dc stage, two different QSC converters are proposed. Compared to Flyback and LLC resonant converters, the QSC converters feature: 1) reduced voltage stress on the primary-side switches to 2/3 of the input voltage; 2) reduced voltage stress on the...
Currently acknowledged, as a rapidly emerging technology, High-Brightness Light-Emitting Diodes (HB-LEDs) are considered the true alternative to many mature technologies (i.e., incandescent bulbs, compact fluorescent lamps, etc.) due to their high efficiency, low maintenance and durability. It is evident that the HB-LED driver must be durable and efficient to achieve these advantages. Moreover, in...
This paper introduces a novel bridgeless resonant ac-to-dc converter, capable of efficiently converting arbitrary low-amplitude input voltages into a regulated dc voltage. High-frequency resonant operation owing to LC resonance allows small footprint for passive components, thereby increasing the circuit power density without suffering from switching losses. A resonant gate drive circuit is designed...
This paper investigates the fast switching characteristics and high temperature performance of the emerging 600 V GaN high-electron-mobility transistor (HEMT) for high efficiency / high temperature applications. First, the inherent switching performance of the GaN HEMT is demonstrated in the double pulse test. The GaN HEMT exhibits superior switching capability, with a di/dt reaching 9.6 A/ns and...
The impact of the shield resistance (Rsh) on the waveform ringing and system efficiency is assessed in this work for 30V trench power FETs with shielded-gate (TP-FETs). Two different approaches, named distributed and local Rsh, are extensively investigated by experimental and numerical simulation tools. A layout distributed Rsh emerges as the ultimate solution to maximize the self-damping without...
This paper presents a guide on characterizing state-of-the-art silicon superjunction (SJ) devices in the 600V range for single phase power factor correction (PFC) applications. The characterization procedure is based on a minimally inductive double pulse tester (DPT) with a very low intrusive current measurement method, which enables reaching the switching speed limits of these devices. Due to the...
This paper presents a general method to measure the output capacitance (Coss) related energy loss per switching cycle in power MOSFETs used in zero-voltage-switched (ZVS) applications. It is shown that a simple model using Coss in series with a resistance Ross is inadequate for describing the observed energy loss and a different model is needed. This work also shows that the traditional hard-switched...
Common Source Inductance (CSI) is the inductance shared by the main current loop and the gate drive loop in a synchronous buck converter. Any voltage induced on CSI will change the effective gate-source voltage of the FET and has significant impacts on converter performance. This paper will explore and verify the impacts of High Side (HS) CSI on converter switch node ringing and power loss. New equations...
This paper analyzes a high efficient SiC MOSFET based inverter without externally antipa-rallelled diodes. To this end, steady-state performances of MOSFET channel and its body diode are demonstrated; proper control and modulation technique is applied to realize synchronous rectification of the inverter and to minimize the conduction loss of body diodes. Power loss analysis of the inverter under various...
This paper presents the evaluation of high-voltage cascode gallium nitride (GaN) high-electron-mobility transistors (HEMT) in different packages. The high-voltage cascode GaN HEMT in traditional package has high turn-on loss in hard-switching turn-on condition, and severe internal parasitic ringing, which could possibly damage the gate of GaN HEMT, in hard-switching turn-off condition, due to package...
This paper describes dynamic characteristics and power loss analysis of a high-voltage GaN-HEMT in cascode. The GaN-HEMT is "normally-on" and fabricated on 6-inch Si substrate using our Si mass-production line. A figure of merit (a product of RDSon (m Ω) and Qg (nC)) of the GaN-HEMT in cascode is as low as 1400. Simple switching characteristics with resistive load and power efficiency measurements...
This study presents the capability to use conventional silicon power semiconductor devices (Si-IGBT, Si-CoolMOS™) at 200°C operating junction temperature in a BOOST converter for traction automotive application. For each die, nano-scale silver sintered die-attach has been used in order to guaranty an optimum heat transfer between the chip and the substrate. Electrical static characterizations (breakdown...
This paper investigates the dc link voltage ripple in a modular multilevel converter (MMC). It is found that switching-frequency ripple occurs on the dc link voltage in MMC when circulating current suppressing control is implemented. The mechanism of the switching-frequency voltage ripple is investigated and explained. Circulating current suppressing control will manipulate the average values for...
Space Vector Modulation (SVM) is a powerful method which enables some freedom to generate the modulation sequences and modify the performances of converter. However, in the multi-level converter structures, the number of switching state redundancies significantly increases, and the determination of modulation sequences becomes ambiguous because there are too many possible combinations and arrangements...
This paper suggests a new method to balance the voltage of the two capacitors in the three-level neutral-point clamped (NPC) converter. The proposed method only needs the information of two capacitor voltages. The two capacitor voltages are fed back to the controller and then the controller generates phase shifting value with which sinusoidal modulation will be adjusted to the left or right. This...
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