Pulse Width Modulation Topology Research Articles

Matrix Coupled All-in-One Magnetics for PWM Power Conversion

This article investigates the matrix coupled “all-in-one” magnetic structure that combines both series coupling and parallel coupling for pulse-width modulated (PWM) power conversion. A systematic analysis of the current ripple reduction mechanism is performed. Current ripple steering among asymmetric series coupled windings is discussed. The transient performance of the matrix coupled inductor is demystified, providing insights for analyzing converter dynamics and its large- or small-signal modeling. To quantify the benefits of matrix coupling, a figure of merit is defined by comparing the current ripple of a matrix coupled inductor to that of a discrete inductor given the same transient speed. The comparison results indicate that a higher number of phases and a stronger matrix coupling coefficient amplify the benefits of matrix coupling. A 1 V-to-5 V input, 1 V-to-5 V output, four-phase matrix coupled synchronous SEPIC converter with planar PCB integrated magnetics is built and tested. The matrix coupled SEPIC prototype can support load current up to 185 A at 5 V-to-1 V voltage conversion with a maximum power density over 470 W/in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\text{3}$</tex-math></inline-formula> . Compared to commercial discrete inductors, the matrix coupled inductor has a 5.6 times smaller size and 8.5 times faster transient speed with similar current ripple and current rating. The experimental results validate the matrix coupling concept and the theoretical analysis, opening the possibilities toward wide adoption of ‘‘all-in-one-magnetics” in PWM topologies.

A Switched Inductor Quasi Z source-H-bridge Multilevel Inverter for Soft starting Control of Induction Motor using Direct Torque and Flux Control

An impedance source multilevel inverter schemes applied for traction and industrial drives application. Because it has unique merits ofharmonics less, transformer less drives control application and also soft start capability of induction drives. This paper proposed a reduced source z source Hbridge multilevel inverter and it is applied for induction motor drive control. In order to improving performance of induction motor performance, the torque and speed control is achieved using Direct Torque and Flux Control (DTFC)via phase voltage and current magnitude control. The proposed control scheme of Direct Torque and Flux Control (DTFC) is calculated through phase voltage and phase current sensing and then stator torque and flux is to be calculated byseparate estimation scheme. In reduced source Z source H-bridge multilevel inverter schemes, z source circuit gives a soft start capability across induction motor drive by controlling power magnitude across DC-Link. Reduced source is achieved using capacitor balancing circuit using a common DC-source. A single carrier and multi-reference of Phase Opposition and Disposition (POD) pulse width modulation topology is uses for proposed reduced source z source Multilevel Inverter for soft start control of induction motor.

Efficient Hybrid Sinusoidal Pulse-Width Modulation Control Schemes for Cascaded Five-Level H-Bridge Inverter-Fed Industrial Drives

The performance of a pulse-width modulation (PWM) technique for soft switched cascaded five-level inverters are emphasised. The hybrid PWM topologies have been on spot light in industrial drives, the cascaded multilevel inverter can be asserted due to high power medium voltage applications. The proposed modulation schemes are hybrid alternative phase opposition disposition, hybrid phase shift carrier, hybrid single carrier sinusoidal PWM (SPWM) schemes. It inherits the switching loss reduction along with reduced harmonic performance of cascaded multilevel inverter fed drive system. The effectiveness of the novel concepts are validated experimentally. Simulation study of the inverter employing the proposed hybrid alternative phase opposition disposition and hybrid single carrier SPWM strategies has been done in MATLAB/Simulink. Among the existing design the efficient strategy is employed in the hardware implementation of hybrid multilevel inverter.

Efficient hybrid sinusoidal pulse-width modulation control schemes for cascaded five-level H-bridge inverter-fed industrial drives

The performance of a pulse-width modulation (PWM) technique for soft switched cascaded five-level inverters are emphasised. The hybrid PWM topologies have been on spot light in industrial drives, the cascaded multilevel inverter can be asserted due to high power medium voltage applications. The proposed modulation schemes are hybrid alternative phase opposition disposition, hybrid phase shift carrier, hybrid single carrier sinusoidal PWM (SPWM) schemes. It inherits the switching loss reduction along with reduced harmonic performance of cascaded multilevel inverter fed drive system. The effectiveness of the novel concepts are validated experimentally. Simulation study of the inverter employing the proposed hybrid alternative phase opposition disposition and hybrid single carrier SPWM strategies has been done in MATLAB/Simulink. Among the existing design the efficient strategy is employed in the hardware implementation of hybrid multilevel inverter.

Novel Two-Phase Interleaved LLC Series-Resonant Converter Using a Phase of the Resonant Capacitor

An LLC series-resonant converter has many unique characteristics and improvements over pulsewidth-modulation topologies. However, many output capacitors are needed in parallel to satisfy an output voltage ripple and a rated ripple current of the capacitors. This paper deals with a novel two-phase interleaved LLC resonant converter using a phase of the resonant capacitor. The proposed converter satisfies low output-voltage ripple requirement and meets the rated ripple of output capacitor's current with few output capacitors. The operation and features are considered in detail, and a prototype with a 12-V-100-A output is investigated.

Analysis and evaluation of zero‐voltage‐transition converters applied to DC motor drives

AbstractZero‐voltage‐transition (ZVT) converters which combine pulse‐width modulation (PWM) with the soft‐switching characteristics have very low voltage and current stress and the soft switching of the rectifier diode. Therefore, ZVT‐PWM converters can increase the switching frequency and consequently reduce the ripple current. Although the ZVT‐PWM converter has the above advantages, the application of ZVT‐PWM converter to DC motor drive has not been discussed until now. This paper will analyse and discuss the characteristics of ZVT‐PWM technique applied to the separately‐excited and series DC motor drives. Effects of switching frequency and duty cycle on efficiency, speed characteristic and ripple current for the various DC motors are also investigated. The comparison of the ZVT‐PWM converter‐fed DC motor with the traditional hard‐switching PWM topology shows that the ZVT‐PWM converter‐fed DC motor can reduce switching loss and ripple current and improve the efficiency even if the load variation is very large. Furthermore, the performance improvement after the addition of an adequate filter is also appreciated in this paper.

A novel ZVT PWM Cuk power-factor corrector

A novel zero-voltage-transition (ZVT) pulsewidth modulated (PWM) Cuk power-factor corrector (PFC) is proposed to achieve unity power factor under zero-voltage-switching (ZVS) operations. In the proposed ZVT PWM Cuk PFC, not only the power switch, but also the power diode, commutate under ZVS. The proposed topology has the shortest ZVT time and, thus, the shortest minimum duty cycle compared with other ZVT PWM topologies. The resonant inductor can be discharged regardless of the state of the main switch. Extremely short ZVT time and robust discharge of the resonant inductor make the proposed topology well qualified for variable-duty and high switching-frequency applications. Analytical studies, design rules, and experimental waveforms of the ZVT PWM Cuk PFC are presented in detail.