Switch Overheating Protection Method Based on sic MOSFET Loss Model

Abstract

The invention discloses a switch overheat protection method based on a SiC MOSFET loss model. The switch is a SiC MOSFET, which includes the following steps: constructing a loss model of the SiC MOSFET, and estimating the SiC MOSFET by collecting the sampled electrical signal of the SiC MOSFET. Loss; Based on device loss and steady-state thermal network, by collecting the surface temperature of the heat sink of the switching device on the high-speed / ultra-high-speed motor controller, the junction temperature of the SiC MOSFET is estimated, and compared with the preset protection threshold, according to the comparison result , to protect SiC MOSFET from overheating; the system includes DSP control chip, gate drive chip, three-phase two-level inverter, signal sampling circuit, heat dissipation and temperature measurement module, and the DSP control chip is used to implement the switch overheat protection method; this The invention prevents devices from failing or even exploding due to overheating, jeopardizing the safe operation of the system.

Description

technical field [0001] The present application relates to motor control systems, and in particular, to a switch overheating protection method based on a loss model of SiC MOSFETs. Background technique [0002] For high-speed and ultra-high-speed motors, to achieve good control accuracy, the inverter circuit needs to work at a higher switching frequency, which will lead to an increase in the loss of switching devices in the inverter circuit. Increased losses will increase the temperature of the switching device, and when it reaches its threshold, it will cause the device to overheat and fail or even explode, compromising the safe operation of the system. [0003] After years of development, the performance of silicon-based semiconductor power switching devices has approached the limit of its material application, and it is slightly difficult in the application of high-speed and ultra-high-speed motors. SiC MOSFET has the characteristics of fast speed, high temperature resista...

AI Technical Summary

Problems solved by technology

[0002] For high-speed and ultra-high-speed motors, in order to achieve good control accuracy, the inverter circuit needs to work at a higher switching frequency, which will increase the loss of switching devices in the inverter circuit

The increase in loss will cause the temperature of the switching device to rise continuously, and when it reaches its threshold, it will cause the device to overheat and fail or even explode, thus endangering the safe operation of the system

[0003] After years of development, the performance of silicon-based semiconductor power switching devices is close to the limit of its material application, and it is a little difficult in the application of high-speed and ultra-high-speed motors. SiC MOSFET has the characteristics of fast speed, high temperature resistance, low loss and fast heat dissipation. It is more in line with the development requirements of power switching devices, but the loss calculation method of the original switching device is not suitable for the motor control system based on SiC MOSFET, so it is necessary to establish a loss calculation method suitable for SiC MOSFET, and according to the relationship between loss and junction temperature in the system Switching device junction temperature for real-time estimation and thermal protection

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