Temperature detection circuit of frequency converter

Abstract

The invention provides a temperature detecting circuit of a frequency converter. The temperature detecting circuit comprises a temperature collecting circuit and a data transmitting circuit. The temperature collecting circuit comprises a plurality of branch circuits. The input end of each of the branch circuits is connected to multiple temperature switches for temperature detection and / or thermistors distributed in the frequency converter, and the temperature collecting circuit compares the voltage of the output end of each of the branch circuits and outputs voltage Umax of a maximum value. The output end of the data transmitting circuit is connected to a single-chip microcomputer of the frequency converter by an AD interface and transmits a processed voltage signal to the single-chip microcomputer, thus the single-chip microcomputer calculates the highest temperature in the multiple temperature switches and / or thermistors according to the voltage signal. According to the temperature detecting circuit of a frequency converter, a detection mode with the temperature switches and / or thermistors as detection components is satisfied, the highest temperature in the frequency converter can be determined, thus overheat protection is facilitated, and the occasion of application is wide.

Description

technical field [0001] The invention relates to the fields of power electronics and motor control, in particular to a temperature detection circuit of a frequency converter. Background technique [0002] The frequency converter is a power control device that uses the on-off function of power semiconductor devices to convert the power frequency power supply into another frequency. Overvoltage / overload protection and other functions. [0003] Due to the large output current of the high-power inverter, most of the three-phase inverter modules of the inverter are discrete, and the radiator of the inverter is relatively large, so it is necessary to collect the temperature of multiple points of the radiator. Generally, two kinds of temperature sensors are used for temperature detection, namely temperature switch and thermistor. When using the detection method of the temperature switch, it basically uses multiple temperature switches (normally open) in parallel and then inputs th...

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Problems solved by technology

When using the detection method of the temperature switch, it basically uses multiple temperature switches (normally open) in parallel and then inputs them into the hardware circuit for detection and judgment, but the temperature switch is only a switch and cannot detect the actual temperature of the current inverter. , not applicable in some occasions; when using the thermistor detection method, because the temperature of multiple IGBT modules needs to be collected, AD interfaces of multiple single-chip microcomputers are often required, which may cause insufficient AD interface resources of the single-chip microcomputer

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