Frequency converter temperature and humidity control system and control method

Abstract

The invention discloses a frequency converter temperature and humidity control system and a control method. The system comprises a detection unit and a control unit, the detection unit is used for collecting the environment temperature and environment humidity in a frequency converter and the surface temperature of a capacitor, and the control unit is electrically connected with the detection unitand the frequency converter, and is used for processing the environment temperature, the environment humidity and the surface temperature data and sending a control signal for stopping running or starting to the frequency converter according to a processing result. According to the invention, the controller monitors the change of the ambient temperature and humidity in the frequency converter andthe surface temperature of the capacitor of an intermediate circuit in real time, so that explosion accidents of the frequency converter due to over-high temperature of the capacitor of the intermediate circuit or over-high humidity in the frequency converter can be prevented; meanwhile, necessary and effective data reference can be provided for maintenance of the frequency converter through themonitoring data, and finally protection control over the frequency converter is achieved.

Description

technical field [0001] The invention relates to the technical field of frequency converters, in particular to a frequency converter temperature and humidity control system and control method. Background technique [0002] Inverter is a kind of equipment that uses software control algorithm and hardware control system to control the on and off of power semiconductor devices, so as to convert the industrial frequency power supply into AC power supply of various frequencies, and realize the variable speed operation of the motor. It is a device in the motion control system. power converter. At present, the AC-DC-AC voltage inverter is the most widely used, that is, there is a DC energy storage filter link in the middle, and a large-capacity electrolytic capacitor is generally used to realize this function. [0003] When the inverter is running, if the ambient temperature is higher than 40°C, the inverter will be derated by 5% for every 1°C higher. In addition, the ripple curre...

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Problems solved by technology

In addition, the ripple current flows through the electrolytic capacitor for a long time, and the oxidation of the electrode of the electrolytic capacitor leads to an increase in internal resistance, which causes an increase in leakage current, an increase in temperature rise, and an increase in heat generation, which further causes a decrease in the electrolyte and a decrease in capacity.

On the one hand, the reduction in capacity will easily cause the electrolytic capacitor to resonate with the equivalent inductance (including load inductance) of the inverter circuit of the inverter, resulting in overvoltage that will cause the inverter module and rectifier module of the inverter to be broken down; on the other hand, it will cause the inverter The load capacity and power factor decrease, and when the load is heavy, the DC bus voltage will drop sharply, causing the inverter to alarm or even stop

[0004] If the inverter is placed in an environment with high humidity for a long time, many small water droplets will condense on the circuit board. If the water droplets are just between the two electrodes of the electrolytic capacitor on the circuit board, it will inevitably cause the capacitance value of the electrolytic capacitor to change or the insulation to drop. Breakdown occurs

If water droplets are on the DC bus circuit or terminals, phase-to-phase short-circuit or DC discharge accidents will occur when starting operation

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