Comprehensive Review on Harmonic Suppression by Filters in PWM Inverter Circuits

As a core component of modern power electronics technology, PWM inverter circuit plays an important role in the fields of motor drive, renewable energy grid connection and power transmission. However, due to its high-frequency switching characteristics, the circuit introduces significant harmonic components in the output voltage and current, which affects power quality and may cause equipment loss, electromagnetic interference and grid stability problems. In order to effectively suppress harmonics, the filter has been widely used in PWM inverter circuit. Based on the impedance characteristics of passive components, the passive filter weakens the harmonics of a specific frequency through the LC or LCL network. Its structure is simple and its loss is low, but it has poor adaptability to dynamic harmonics. Relying on real-time harmonic detection and power conversion technology, the active filter can dynamically compensate for different load conditions, improve the harmonic suppression effect, and enhance the adaptability of the system to load fluctuations. The hybrid filter combines the advantages of passive and active filters, and improves the harmonic suppression ability while reducing the power loss. It is especially suitable for high-power inverter systems and complex load environments.