高压变频器是一种利用电力半导体器件的通断作用将工频电源变换为另一频率的电能控制装置,它可以控制交流电动机的转速。随着现代电力电子技术和微电子技术的迅猛发展,高压大功率变频调速装置不断地成熟起来,原来一直难于解决的高压问题,近年来通过器件串联或单元串联得到了很好的解决。高压变频器的种类繁多,其分类方法也多种多样。
Application field
At present, PLC controller has been widely used in steel, petroleum, chemical, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection and culture and other industries, the use of the situation can be roughly summarized as the following categories.
Logic control of switching quantity
This is the most basic PLC controller, the most extensive application field, it replaces the traditional relay circuit, to achieve logic control, sequence control, can be used for single equipment control, can also be used for multi-machine group control and automation line. Such as injection molding machines, printing presses, stapler machines, combined machine tools, grinding machines, packaging production lines, electroplating lines, etc.
Analog control
In the industrial production process, there are many continuously changing quantities, such as temperature, pressure, flow, liquid level and speed, which are analog quantities. In order for A programmable controller to handle Analog, it is necessary to realize A/D conversion and D/A conversion between analog and Digital. PLC manufacturers have produced supporting A/D and D/A conversion modules, so that programmable controllers are used for analog control.
Motion control
The PLC controller can be used to control circular motion or linear motion. In terms of the configuration of the control mechanism, the early I/O module was directly used to connect the position sensor and the actuator, and now the dedicated motion control module is generally used. For example, a single or multi-axis position control module that can drive a stepper motor or a servo motor. The products of the world’s major PLC controller manufacturers almost all have motion control functions, which are widely used in various machinery, machine tools, robots, elevators and other occasions.
Process control
Process control refers to the closed-loop control of analog quantities such as temperature, pressure and flow. As an industrial control computer, PLC controller can compile a variety of control algorithm programs to complete closed-loop control. PID regulation is a common method used in closed-loop control system. Large and medium-sized PLC have PID module, many small PLC controllers also have this function module. PID processing is generally run a special PID subroutine. Process control is widely used in metallurgy, chemical industry, heat treatment, boiler control and so on.
The high voltage inverter is a kind of power control device that converts the power frequency power supply to another frequency by the on-off action of the power semiconductor device, which can control the speed of the AC motor. With the rapid development of modern power electronic technology and microelectronics technology, high voltage and high power frequency conversion speed regulation devices continue to mature, the original has been difficult to solve the high voltage problem, in recent years through the device series or unit series has been a good solution. There are many kinds of high voltage inverters, and their classification methods are also various.