Power unit control plate of high-voltage frequency converter

Abstract

The invention relates to a power unit control plate of a high-voltage frequency converter. The power unit control plate is connected between a main control plate of the high-voltage frequency converter and a power unit of the high-voltage frequency converter, and is a receiving-transmitting serial communication structure; receiving serial communication is defined from the main control plate to the power unit, and transmitting serial communication is defined from the power unit to the main control plate; and an input serial communication signal firstly passes through an input buffer filter circuit to filter out an interfering signal so as to enhance the current drive capability and interference-free feature of the signal, thereby furthest reducing the electromagnetic interference influence in communication. The power unit control plate comprises an address dip switch which is connected with a programmable logic device and is corresponding to the address of a component in the power unit, thereby guaranteeing that a command is accurately and reliably transferred. A temperature sensor is used for measuring the temperature of the component in the power unit and transferring a characteristic curve to adjust the opening voltage of the component so that the opening loss of the component reaches the optimum.

Description

technical field [0001] The invention relates to a control board, in particular to a power unit control board of a high-voltage frequency converter. Background technique [0002] In practical applications, high-voltage frequency conversion speed regulation technology is mainly used in high-voltage motor speed regulation systems, and it is recognized as the first choice for its excellent speed regulation and braking performance, high efficiency, high power factor and wide application range. The most promising way of speed regulation. In the case of large changes in load conditions such as fans and pumps, the use of AC speed regulation technology has obvious energy-saving effects and can achieve the purpose of energy saving and emission reduction. [0003] The development of high-voltage frequency converters has gone through a variety of topological structures, and so far, no unified topological structure has been formed. At present, the most popular ones on the market are vo...

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Problems solved by technology

However, because the power unit control circuit board itself works in a harsh electromagnetic radiation environment, the communication signal may be strongly interfered on the power unit control circuit board, resulting in incorrect switching of Q1, Q2, Q3 and Q4, or causing the main The control board incorrectly receives the information of the power unit, resulting in misjudgment

[0008] B. The operating temperature of the H-bridge composed of IGBT devices is too high, so that the power unit cannot continue to work

Since the H-bridge (Q1, Q2, Q3 and Q4 consists of four IGBT devices) works in frequent on and off states, there will be a certain power loss when it is turned on and off, and the lost power will be converted into heat, which will cause power unit If the heat dissipation of the power unit is not good (there is a problem with the air exchange channel of the whole machine, the external air environment temperature is too high and other factors may cause this phenomenon), after a long time of operation, the working temperature will inevitably be too high and damage the power unit. The phenomenon of components

The power loss of the IGBT device is related to the driving voltage Vgs of the IGBT device and the operating temperature of the IGBT device. Increasing the turn-on driving voltage Vge of the IGBT device can reduce the power loss when the IGBT device is turned on, but the turn-on voltage cannot be increased without limit. When the value of the IGBT device itself will be damaged

Therefore, when factors such as circuit inductance and parasitic capacitance are considered comprehensively, in general, the current turn-on voltage of IGBT devices is fixed at a safe value considered by the manufacturer, but the so-called safe value is not the best value to minimize the loss of IGBT devices

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