China
Africa
Explore chapters and articles related to this topic
High Speed Counter and PWM Macros
Published in Murat Uzam, PIC16F1847 Microcontroller-Based Programmable Logic Controller, 2020
The explanations provided in this section are mainly from [R2.1]. Pulse width modulation (PWM) is a scheme that provides power to a load by switching quickly between fully ON and fully OFF states. The PWM signal resembles a square wave where the HIGH portion of the signal is considered the ON state and the LOW portion of the signal is considered the OFF state. The HIGH portion, also known as the pulse width (PW), can vary in time and is defined in steps. A larger number of steps applied, which lengthens PW, also supplies more power to the load. Lowering the number of steps applied, which shortens the PW, supplies less power. The PWM period T is defined as the duration of one complete cycle or the total amount of ON and OFF time combined. PWM resolution defines the maximum number of steps that can be present in a single PWM period T. A higher resolution allows for more precise control of the PW time and in turn the power that is applied to the load. The term “duty cycle” (DC) is defined as the ratio between the ON time (PW) and the period (T) of a square waveform, and is expressed in percentages, where 0% is fully OFF and 100% is fully ON. A duty cycle DC (%) may be expressed as shown in Equation 2.1. DC=PWT100%
P
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
pulse-width modulated switch an active switch driven by a pulse-width modulated (PWM) pulse train. pulse-width modulation (PWM) a control technique used in variable speed DC, AC, or other electrical variable speed drives to control the harmonic content of the applied voltage or current. Typically, the pulse width is modulated in three ways, trailing-edge modulation, leadingedge modulation, and double-edge modulation. Most popular is sinusoidal PWM for AC drives. PWM is most frequently used in switching converter technology as the drive signal for active switching elements. pulsed laser laser designed to produce its output in the form of isolated or periodic pulses that may be either long or short compared to the length of the laser cavity. pulsed network a network that conveys information between neurons by means of pulse streams. The information may be coded using conventional pulse modulation techniques or by using random bit streams, in which case the information is coded into the statistics of the stream.
Signal Conversion Methods
Published in Clarence W. de Silva, Sensor Systems, 2016
In pulse-width modulation (PWM), the carrier signal is a pulse sequence of constant amplitude. The pulse width is changed in proportion to the amplitude of the data signal while keeping the pulse spacing (pulse period) constant. This is illustrated in Figure 4.1d. Suppose that the high level of the PWM signal corresponds to the “on” condition of a circuit and the low level corresponds to the “off” condition. Then, as shown in Figure 4.2, the pulse width is equal to the on time ΔT of the circuit within each signal cycle period T. The duty cycle of the PWM is defined as the percentage on time in a pulse period and is given by () Duty cycle = ΔTT×100%
Design and Development of SECU Converter Cascaded Control for EV Applications
Published in Electric Power Components and Systems, 2023
Jenifer Arockia Raj, Sukhi Yesuraj
The average voltage across the energy transfer capacitors and output capacitors is obtained as The average current in the input inductors is and The switching design of a power converter determines the switching sequence and timing of the semiconductor devices to regulate the output voltage or current. The Pulse Width Modulation (PWM) pattern is a technique used in switching converters to control the duty cycle of the pulse train applied to the switch, which regulates the output voltage. It involves comparing a reference signal with a triangular waveform to generate a modulated waveform that controls the switch.
Design and control of a sit-to-stand assistive device based on analysis of kinematics and dynamics
Published in Automatika, 2021
Binwei Zhou, Qiang Xue, Shuo Yang, Huaiqiang Zhang, Tongtong Wang
Trajectory control was needed to make the assistive device run according to the law of STS motion of healthy people. In the process of mechanism design and motion simulation, we obtained the law of velocity of the linear actuator, so we needed to realize this law through the control system. Pulse Width Modulation (PWM) can adjust the duty ratio, change the ratio of high and low level in a cycle, then change the output voltage in that cycle, control the velocity of the motor, and achieve velocity control of the linear actuator. In Arduino, we can use the analogWrite (pin, value) function to complete PWM output, where pin represents the Arduino pin to write to, and value is used to control the duty ratio between 0 (always off) and 255 (always on). When the value is 0, the duty ratio is 0%, the output voltage is 0, the velocity of the linear actuator is 0, and the linear actuator is in a static state; when the value is 255, the duty ratio is 100%, the output voltage is the maximum input voltage, and the velocity of the linear actuator is the maximum.
Research of the equivalent relationship between the space vector and the triangular carrier-based PWM modulation strategies in the flying capacitor multilevel inverters
Published in International Journal of Electronics, 2019
Chao Wang, Yingjie He, Yue Wang, Jinjun Liu
PWM control refers to the pulse width modulation technology. That means the waveform can be equivalently obtained through a series of pulse width modulation, and the CBPWM is pulse width changes according to the law of sine and equivalent sine wave PWM waveform. In the practical application, the modulation wave and the carrier are compared to get the corresponding PWM signal, so we can realise the control of the inverters. And it is widely used because the principle is clear and convenient. Figure 4 shows the five-level inverter CBPWM modulation waveform.