A Research on Thermal Properties of Brushless Motor Drives for Aerospace Use

Connected to an electric motor via the switching circuit through the direct current (DC) power supply, a brushless motor drive controls the rotating speed of the motor under the condition of input signals with different duty cycles. This paper focuses on the problem resulting in the burning of the overheating drive. For that, the paper relies on numerical simulation to offer thermal distribution data about the internal components of the device when being used in the extreme condition for satellite models, i.e. with the rated voltage and maximum load current, and then to analyze the reasonableness of their layout; at the same time, the paper gives the minimum dimensions of the heat sink mounted to the brushless motor drive used in the worst condition, followed by a simulation and testing of the temperature distribution in relation to the drive's case. The simulation and testing results indicate that when used with high temperature, the drive with a built-in heat sink is able to meet the demand for using the device with the case temperature lower than 125°C and the junction temperature lower than 150°C. The research findings of this paper can provide technical support for the design and use of brushless motor drives.