2 Effects of noise and interference

The effects of noise and interference from power electronics converters vary based on the frequency, amplitude, and duration of the disturbances, as well as the characteristics of the affected devices and systems. Some of the common effects include EMC issues, harmonic distortion, voltage fluctuations, and audible noise. EMC issues can cause malfunctions, errors, or failures that compromise the safety, functionality, and quality of the devices and systems. Harmonic distortion can distort voltage and current waveforms, reducing power factor and efficiency. Voltage fluctuations can affect stability and performance of the converter and other devices. Audible noise can cause annoyance or discomfort to people or animals exposed to it. To avoid these effects, power electronics converters must comply with relevant EMC standards and regulations which specify maximum allowable levels of noise and interference.

3 Noise and interference reduction techniques

There are several techniques that can be used to reduce noise and interference from power electronics converters, such as switching frequency optimization, snubber circuits, filtering, and shielding. Optimizing the switching frequency can shift the noise and interference to a frequency range that is less harmful or easier to filter. Snubber circuits can suppress voltage and current spikes, reducing electromagnetic fields and conducted and radiated interference. Filtering is the process of removing or attenuating unwanted components of the noise and interference. Shielding is the process of enclosing or covering the converter circuit with a conductive material, such as metal or foil, which can reduce radiated interference and susceptibility of the converter and other devices. All of these techniques can help improve power quality and EMC performance of the converter.

4 Noise and interference measurement and analysis

To manage the noise and interference from power electronics converters effectively, it is necessary to measure and analyze them accurately and reliably. Oscilloscopes can be used to display the voltage and current waveforms of the converter and other devices, as well as monitor the switching actions, harmonic distortion, voltage fluctuations, and snubber circuits. Spectrum analyzers can show the frequency spectrum of the noise and interference, their magnitude, frequency, bandwidth, harmonic and intermodulation products. Power analyzers can display the power parameters of the converter and other devices, such as active power, reactive power, apparent power, power factor, efficiency, and energy consumption. Sound level meters are devices that measure the sound pressure level of audible noise by showing its intensity, frequency, duration, equivalent continuous sound level (Leq), and sound exposure level (SEL). All these instruments and methods can help to monitor the conducted and radiated interference, switching frequency, filtering of the converter, power quality, audible noise effects on humans or animals.

5 Noise and interference management strategies

Based on the measurement and analysis of the noise and interference from power electronics converters, it is possible to develop and implement effective noise and interference management strategies. These strategies include noise and interference mitigation, which involves applying reduction techniques to the converter and other devices; noise and interference compensation, which involves adjusting control parameters of the converter; and noise and interference avoidance, which involves selecting or designing the converter and other devices to minimize generation or exposure of the noise. Each of these strategies can improve performance, reliability, accuracy, efficiency, flexibility, compatibility, robustness, and quality of the converter and other devices. Additionally, they can reduce environmental impact and regulatory compliance costs.