Short-circuit detection system and method of transducer brake unit

Abstract

The invention discloses a short-circuit detection system and method of a transducer brake unit. The system comprises a comparator, a first adjustable resistor, a second adjustable resistor, a diode and a detection controller, wherein one end of the first adjustable resistor is connected with the negative input end of the comparator, and the other end of the first adjustable resistor is connected with a power supply; one end of the second adjustable resistor is connected with the negative input end of the comparator, and the other end of the second adjustable resistor is grounded; the output end of the comparator is connected with the detection controller, the positive input end of the comparator is connected with the positive electrode of the diode, and the negative electrode of the diodeis connected with one end of a brake tube in parallel. The method comprises the steps that after the brake tube is turned on, an operator waits for 3 us and then detects the voltage at the two ends ofthe brake tube, and if short circuit occurs, the comparator is turned over, and the detection controller sends out a signal to control the brake tube to be turned off. By means of the short-circuit detection system and method, the voltage at the two ends of the brake VCE can be accurately detected, erroneous judgment can be avoided, and a real-time protection can be provided for the brake tube ofthe transducer.

Description

technical field [0001] The invention relates to the research field of detection and protection of a braking unit of a frequency converter, in particular to a short-circuit detection system and method for a braking unit of a frequency converter. Background technique [0002] For the internal electrical structure of the inverter, see figure 1 , mainly including rectifier circuit, soft start circuit, inverter circuit and braking unit. The braking unit is also commonly known as the braking unit. This unit includes the braking tube IGBT1 inside the inverter and the braking resistor externally connected to the inverter. Reduce the excessively high DC bus voltage at both ends of the inverter to avoid overvoltage faults in the inverter. Its working principle is: when the bus voltage is too high (beyond the preset value, that is, the brake point voltage), the controller will send a control signal to turn on the brake tube IGBT1, and the current will flow from +DC through the externa...

AI Technical Summary

Problems solved by technology

Some inverter manufacturers simply judge whether there is a short circuit by detecting the VCE voltage of the brake tube on the hardware. This detection result is not accurate and cannot provide timely protection, so the practicality of the detection is low.

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