Method Of PWM Research Articles

A composite control method of PWM and phase shift for a three-level DC-DC converter

Abstract This research introduces a control strategy for the Three Level Active Half Bridge (TL-DAHB) DC-DC converter that integrates PWM combined with phase-shift control. This composite control method precisely regulates the output voltage by adjusting the phase-shift duty cycle between the input and output sides. Additionally, the application of the PWM control loop optimizes the duty cycle of the switches, effectively reducing the current stress on the converter during operation, improving transmission efficiency, and decreasing conduction losses of the switches. These enhancements boost the overall performance and the reliability of the converter. With its excellent voltage regulation capabilities and safety features, this converter is an ideal choice in the field of power conversion, especially in applications that demand high levels of stability and safety.

Hybrid Modulation Method of PWM and Square-Wave Operation for Single-Phase Solid-State Transformer with ISOP Connection

Hybrid Modulation Method of PWM and Square-Wave Operation for Single-Phase Solid-State Transformer with ISOP Connection

Improving of the Generation Method of Repeated PWM Based on the Signals Combinations Applied to a PV Pumping System

In this paper, we present a new method of the PWM signal generation with repetition of data segments, based on the round robin segment of different amplitudes converters, applied to the photovoltaic water pumping system and the variable frequency variable voltage systems, in order to use the data stored signals to generate other signal amplitudes intermediate to optimize memory usage and reduce the cost of the control board.

Методы широтно-импульсной модуляции мощных активных выпрямителей при несимметрии напряжения

Powerful main electric drive rolling mills are made, usually multi pulses using synchronous motor and frequency converters, consisting of active rectifier and autonomous voltage inverter. Such schemes allow the use of PWM techniques that provide low frequency switching power switches acceptable harmonic structure of the network current transformers and voltage at the point of common coupling. This is due to the property of three-phase systems, ensuring the absence of harmonic multiples of three. These properties are valid only if the symmetry of voltage, so unbalanced currents appear in all odd harmonic spectrum and the application of a low switching frequency becomes invalid. The article presents the results of a study on the mathematical model of the main drive of a cold rolling mill 2000 different methods of PWM in balanced and unbalanced modes. Methods PWM five switchings per quarter period (removing 11, 13, 23, 25 harmonics), with nine switching quarter period (removing 3, 5, 7, 9, 11, 13 harmonics), a method of switching the PWM a quarter of the period and the classical method of PWM. In symmetric modes of the most effective method SHE PWM with five switching quarter period. When the supply voltage unbalance similar results give the classic method of PWM and SHE PWM method with nine switching quarter period. The application of these methods in single-ended modes rather than the other.

A method of single-phase PWM for an independent power supply in photovoltaic power generation systems

We propose a method of single-phase PWM for an independent power supply in photovoltaic power generation systems. This new PWM is derived by comparing levels of signal waves with one of carrier waves which have bipolar swing different from unipolar swing in the conventional PWM. In this PWM, we can use a battery with lower voltage in combination with the photovoltaic power generation; fundamental level of output voltage is raised by about 11%, though poor in quality of waveforms. © 1998 Scripta Technica. Electr Eng Jpn, 122(4): 55–62, 1998

A Method of a Single Phase PWM for a Utility-connected Power Supply in Photovoltaic Power Generation Systems

We propose a method of a sigle phase PWM for a utility-connected power supply in photovoltaic power generation systems. In this paper, the PWM is derived from camparing levels of signal waves with ones of carrier waves which have bipolar swing different from unipolar one in the conventional PWM, and shifting phase a little at exery on-off time. We can expect that array voltage needed is reduced by about 15% and harmonics content contained in output voltage is reduced by about 24% in this PWM in comparison with the conventional with equal output voltage.

A Method of Single Phase PWM for an Independent Power Supply in Photovoltaic Power Generation Systems.

A Method of Single Phase PWM for an Independent Power Supply in Photovoltaic Power Generation Systems.

Digital Control of Electrohydraulic Servo System Operated by Differential Pulse Width Modulation

In the preceding papers, the authors proposed a new method of differential PWM for a hydraulic actuator operated by two 3-way solenoid valves. An arbitrary pulse width of the pressure difference across both sides of the actuator piston was realized by adjusting the switching time of each valve. The actuator operated by differential PWM shows good linearity as a control element, achieving accurate positioning. This study, as an application, deals with a hydraulic servo system composed of a 4-way spool valve and a load cylinder, where the spool valve is driven directly by the differential PWM actuator. The servo system is designed based on the optimal regulator method of the state variable model. The system performance is investigated through simulations and experiments. Consequently, it is shown that the actuator, operated by differential PWM, plays the role of a linear control element, and that the servo system is well designed by the optimal regulator.

Differential PWM Control of Hydraulic Actuator System with Locking Mechanism.

In the preceding papers, the authors proposed a method of the differential PWM for a hydraulic actuator operated by two 3-way high-speed solenoid valves. The actuator operated by this method shows good linear characteristics as a controller which achieves accurate positioning. However, when the actuator is connected to a load with large force over Coulomb friction, an oscillatory motion appears in the steady state. Therefore, the actuator control system becomes considerably inaccurate. To solve this problem, a new type of actuator, which has 4 check valves, is designed in this study. The dynamic characteristics of the actuator, which has a spring as a load, are investigated by simulations and experiments. Consequently, it is clarified that the actuator can be controlled with high accuracy, retaining a merit of the differential PWM method, and moreover, that the permanence of the proposed actuator can be improved by adopting a locking mechanism.