What is the expected result for the driven asynchronous machine when there is a malfunction in one low-side switch of a frequency inverter?

When there is a malfunction in one low-side switch of a frequency inverter driving an asynchronous machine, more torque ripple and increased noise are expected due to the unbalanced current flow and irregular switching pattern. The low-side switch controls the flow of current to the motor. If one switch fails, it disrupts the intended control of the motor phases.

This imbalance can lead to a situation where the current flowing through the motor phases is uneven, resulting in fluctuating torque, also known as torque ripple. This ripple is manifested as variations in the torque produced by the motor at a given speed, causing instability and operational noise. The malfunction causes disruptions in the smooth operation of the frequency inverter, creating a less efficient magnetic field and leading to these adverse effects.

While other scenarios like decreased efficiency might occur due to various reasons, the most immediate and noticeable outcome of a failed low-side switch is the increase in torque ripple and noise, making this response the most relevant and accurate.