The impact of harmonics produced by inverters on transformers

An inverter is a device that converts DC power into AC power. It is widely used in modern industrial production and family life. . However, the impact of harmonics generated by the inverter on the transformer cannot be ignored. This article will discuss the impact of harmonics generated by the inverter on the transformer in detail, detail, and detail, analyze its causes, and propose corresponding solutions.

1. Harmonics generated by inverters

Harmonics refer to the presence of components of different frequencies in the waveform within a cycle. It is a common type of electrical energy in power systems. Quality issues. The harmonics generated by the inverter are mainly divided into two types: full-cycle harmonics and half-cycle harmonics.

Whole-cycle harmonics refer to the harmonics that exist in the inverter output voltage during the entire cycle, and its frequency is an integer multiple of the inverter switching frequency. Full-cycle harmonics are mainly caused by the rectangular waves output by the inverter, which will have a certain impact on the power grid during the transmission process.

Half-cycle harmonics refer to harmonics that appear between the inverter switches, and their frequencies are odd multiples of the inverter switching frequency. Half-cycle harmonics are mainly generated by the deformation of the sine wave output by the inverter, which will have a certain impact on the power grid and the inverter itself.

2. The impact of harmonics generated by the inverter on the transformer

The harmonics generated by the inverter will be transmitted back to the power grid through the transformer, affecting the normal operation of other equipment. Work. Its impact on the transformer is mainly manifested in the following aspects:

1. Fundamental wave distortion

Due to the existence of harmonics generated by the inverter, it is transmitted to the transformer The voltage and current are no longer sine waves, but distorted waveforms. This changes the amplitude and phase angle of the fundamental wave, affecting the operational stability of the transformer.

2. Increase in temperature rise

The harmonics generated by the inverter will cause an increase in eddy current losses in the transformer, thereby increasing its temperature rise. This will lead to insulation aging and shortened life of the transformer.

3. Increased noise

The harmonics generated by the inverter will also cause disturbances in the electromagnetic field inside the transformer, producing noise. This not only affects the user experience of the equipment, but also affects the safe operation of the transformer.

4. Increase in induced voltage

The harmonics generated by the inverter will cause an increase in the induced voltage in the transformer, thereby damaging the insulation system of the transformer. This is because induced voltages are generated by eddy currents in the transformer windings, and increased eddy current losses can cause the windings to heat up, thereby damaging the insulation system.

3. Methods to reduce the impact of inverter harmonics on transformers

In order to solve the impact of harmonics generated by inverters on transformers, some corresponding measures can be taken The measures are as follows:

1. Use a filter

The filter can filter out the harmonics generated by the inverter. Commonly used filters include harmonic filters, active filters and passive filters. The harmonic filter connects the LC circuit in series in front of the transformer and generates resonance by adjusting the resonant frequency to filter out the harmonics; the active filter uses new devices to control the harmonic flow and harmonic voltage to eliminate harmonics; the passive filter The harmonics are limited to a certain range by changing the impedance of the harmonics.

2. Use a harmonic suppressor

A harmonic suppressor is a device that suppresses the harmonics generated by the inverter, which can effectively reduce the Effect of generated harmonics on transformer. Its working principle is to use high-frequency inductor and capacitor filtering to separate the harmonic flow, and at the same time use PWM technology to control the inverter output waveform so that the harmonic current of the waveform is relatively small.

3. Optimize the control algorithm of the inverter

By optimizing the control algorithm of the inverter, the harmonics generated by the inverter can be reduced, thereby reducing its impact on the transformer. Influence. Commonly used control algorithms include SPWM, SVPWM and DPWM.

Through the application of the above measures, the impact of harmonics generated by the inverter on the transformer can be effectively reduced, and the power quality and stability of the power system can be improved.

In short, the problem of harmonics generated by the inverter has a serious impact on the normal operation of the power system and equipment, and corresponding measures need to be taken to deal with it. By using filters, harmonic suppressors and optimizing the control algorithm of the inverter, the harmonics generated by the inverter can be effectively reduced, thereby ensuring the safe operation of the power system and equipment.