Cpld control to realize the frequency converter and control realization method of the minimum pulse width limitation

Abstract

The invention relates to a frequency converter and a control realization method for CPLD control to realize the minimum pulse width limitation, mainly including a main control module and a CPLD programmable logic device, and is characterized in that: a control module and a monitoring module are integrated inside the CPLD; a control module integrated inside the CPLD The PWM pulse sent to CPLD is processed accordingly; the monitoring module integrated in CPLD monitors and controls the overcurrent signal of IGBT and its driving circuit. The system block diagram illustrates the operation and processing performed by the CPLD after the PWM pulse waveform is sent to the CPLD. The monitoring module in the CPLD mainly detects the overcurrent protection signal, and the CPLD will lock the output of the PWM pulse when the overcurrent protection occurs. The effective results are: reduce the cost, reduce the switching loss and reduce the insulation damage of the motor at the same time, and ensure the reliable operation of the equipment; simplify the CPLD over-current protection process, CPLD optimizes the control command of the single-chip microcomputer, and improves the calculation efficiency of the single-chip microcomputer.

Description

technical field [0001] The invention relates to the application field of frequency converter control, in particular to a CPLD program control that limits the minimum pulse width, reduces switching loss and reduces motor insulation damage, and uses CPLD to improve the efficiency of a single-chip microcomputer and ensure reliable operation of equipment to achieve minimum pulse width limitation. The frequency converter and the method of control realization. Background technique [0002] With my country's increasing emphasis on energy saving, in the industrial environment, the flexible control, energy saving and efficiency enhancement and low-cost maintenance brought by the inverter are beyond doubt, but in some of these applications, the distance between the load motor and the inverter The distance is relatively long. When the cable connecting the motor to the inverter is too long, the long cable of the motor will cause an instantaneous overvoltage on the motor terminal, which w...

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Problems solved by technology

[0002] As our country pays more and more attention to energy saving, in the industrial environment, the flexible control, energy saving and efficiency enhancement and low-cost maintenance brought by the frequency converter are beyond doubt. The distance is relatively long. When the cable connecting the motor to the inverter is too long, the long cable of the motor will cause instantaneous overvoltage on the motor terminal, which will have a considerable impact on the life of the winding insulation, and in severe cases will cause Motor insulation failure

[0003] Its impact on the inverter is: the main risk caused by the overcurrent of the inverter is short-circuit fault

Due to the extremely fast turn-on and turn-off speed of the IGBT (up to within 1 microsecond), the peak current brought by it is read to the microprocessor through the current sensor of the inverter, and when it reaches a certain level, it will cause a short circuit or ground fault of the inverter

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