Title: Overview of PWM rectification technology

Summary. The main features of PWM technology include the following:1

High precision: PWM technology can achieve high-precision output control, and the width and frequency of the pulse can be adjusted as needed. 2.

High efficiency: PWM technology can achieve high-efficiency energy conversion in different circuits, thereby improving the efficiency of the circuit. 3.

Good stability: PWM technology can achieve stable output control, which is not affected by power supply voltage and load changes. 4.

Flexible control: PWM technology can achieve precise control of the circuit by changing the width and frequency of the pulses, providing flexibility. 5.

Low cost: PWM technology is relatively inexpensive to implement and can be widely used in many applications.

Good. Good evening, PWM is an abbreviation for Pulse Width Modulation, which is a commonly used analog signal processing technique. It controls the output level of the buried lead circuit by varying the width of the pulse, so that the control of the circuit can be realized.

PWM technology is mainly used in motor control, LED dimming, audio amplifiers and other fields.

The main features of PWM technology include the following:1High precision:

PWM technology enables high-precision output control, and the width and frequency of pulses can be adjusted as needed. 2.High efficiency:

PWM technology can achieve high-efficiency energy conversion in different circuits, thus improving the efficiency of circuits. 3.Good stability:

PWM technology enables stable output control that is not affected by changes in supply voltage and load. 4.Flexible control:

PWM technology can achieve precise control of the circuit by changing the pulse width and frequency chain hail rate, and has flexible bay delay. 5.Low cost:

PWM technology is relatively inexpensive to implement and can be widely used in many applications.

2What are the main types of rectifier circuits? What are the advantages of PWM rectification? + (5 points).

The main types of rectifier circuits are: single-phase half-wave whole-beam land-blocking current, oak-hu single-phase full-wave rectification, single-phase bridge rectification, three-phase rectification and doubled pressure rectification. The advantage of PWM rectification is that there is no internal power loss and it is suitable for automatic adjustment of the output voltage, and in high-end applications, PWM rectification is the mainstream.

Generally speaking, PWM (pulse width modulation) is to adjust the ratio of input and output voltage, that is, to adjust the buried output voltage and sliding resistance, which can reduce the resistance loss of the whole system, compared with the transformer method, can reduce the volume of the whole system, and reduce the application of materials.

Answer]: The diode rectifier circuit can convert alternating current into direct current, but due to the uncontrollable and unidirectional conductivity of the diode, the electric energy can only be transmitted from the AC side to the DC side and the output voltage is not controlled.

The thyristor rectifier circuit adopts a semi-controlled device to make the output voltage controllable, and under certain conditions, it can also realize the feedback of direct current energy to the Changliu power grid. However, the output voltage and input current of the circuit also contain large ripple and harmonic components.

The PWM rectifier circuit adopts fully controlled power electronic devices and uses PWM control technology, so that it can not only work in the rectification and inverter state, but also work in the controllable state of power factor, and at the same time, the harmonic component in the input current can be greatly reduced through PWM control technology.

1.The basic meaning of PWM and the meaning of the main technical indicators are given, and the main uses of PWM are illustrated with examples.

The basic meaning of PWM and the meaning of the main technical indicators are given, and the main uses of PWM are illustrated with examples. Hello dear, PWM (Pulse Width Modulation) control technology is the technology of modulating the width of the pulse, that is, by modulating the width of a series of pulses, the required waveform (including shape and amplitude) can be obtained equivalently. The area equivalence principle is an important basic theory of PWM technology.

A typical PWM control waveform SPWM: the width of the pulse varies according to a sinusoidal pattern. The PWM waveform equivalent to the sine wave is called the SPWM wave.

Pulse Width Modulation (PWM) is a very effective technique for controlling analog circuits using the digital output of a microprocessor, and is widely used in many fields from measurement and communication to power control and conversion. PWM is a method of digitally encoding analog signal levels. Through the use of high-resolution counters, the duty cycle of the square wave is modulated to encode the level of a specific analog Shin Hyozi.

1) PWM control technology characteristics switching power supplies generally use pulse width modulation (PWM) technology, which is characterized by high frequency, high efficiency, high power density and high reliability. However, because the switching device operates in a high-frequency on-off state, the fast transient process of high frequency is itself a source of electromagnetic disturbance (EMD), and the EMI signal it generates has a wide frequency range and a certain amplitude. If this power supply is used directly in a digital device, the EMI signal generated by the device becomes more intense and complex.

One advantage of PWM is that the signals from the processor to the controlled system are all in digital form, and the digital-to-analog conversion is underway. The impact of noise can be minimized. Increased resistance to noise is another advantage of PWM over analog control, and it is the main reason why PWM is used for communication at some point.

Switching from analog signals to PWM can dramatically extend communication distances. (2) Advantages of PWM control technology: Because PWM can realize the characteristics of frequency conversion and voltage conversion and anti-suppression harmonics at the same time. Therefore, it is widely used in AC transmission and other energy conversion systems.

PWM control technology can be roughly divided into three categories: 1. Sinusoidal PWM (including various PWM schemes with voltage, current or magnetic flux as the sinusoidal target, and multiple PWM should also be buried in this category). Sine PWM is already well known.

The multi-PWM technology designed to improve the output voltage, current waveform, and reduce the harmonics of the power system has its unique advantages in high-power inverters. 2. Optimize PWMWmThe pursuit of PWM is to achieve the minimum current harmonic distortion rate (THD), the highest voltage utilization, the best efficiency, and the minimum torque ripple and other specific optimization goals. Hope my answer is helpful to you, <>

The concept is too big to be written in a book, to put it simply:

PWM rectifier circuit is a rectifier circuit composed of PWM control mode and full control device, which can solve the problems of traditional rectifier circuit to varying degrees. The PWM rectifier circuit is formed by applying the SPWM control technology in the inverter circuit to the rectifier circuit. By controlling the PWM rectifier circuit so that the input current is very close to the sine wave and is in phase with the input voltage, the power factor is approximately 1.

Therefore, PWM rectifier circuits are also called unit power factor converters.