Why does harmonic generator produce harmonic? What's his working principle?
Is the inverter harmonics in converter running, need to input power supply of high power diode rectifier (or transistor / inverter module) of inverter; in the inversion process, the high-order harmonic generation in the input / output circuit; inverter harmonic to the power supply system, load and his nearby electrical equipment interference.
Harmonic generation mechanism of inverter inputThe main circuit of inverter is composed of AC-DC-AC, external input 380V/50Hz power supply through the three-phase bridge rectifier, a DC voltage, AC voltage by the capacitor filter and high power transistor switching element for variable frequency inverter. In the rectifying circuit, the input current waveform is a rectangular wave irregular waveform, according to Fu Liye series is decomposed into fundamental and harmonics, the harmonic frequency is usually 6N + 1 harmonic, the harmonic interference input power supply system. If the reactance of the supply side is sufficiently small and the commutation overlap angle can be neglected, then the n order harmonic is the 1/n of the fundamental current.
Harmonic generation mechanism of converter outputIn the inverter output loop, the output current signal is a pulse waveform modulated by the PWM carrier signal. For GTR high-power inverter component, the carrier frequency of PWM is 2-3kHz, while the maximum carrier frequency of IGBT high-power inverter component is 15kHz, PWM. Similarly, the output loop current signal can also be decomposed into only the fundamental wave and other harmonics.
The working principle of the inverter is the first AC into DC, because the alternating current is not directly change its frequency, according to the parameter setting of the machine, and then the DC into AC power, and then drag to load.
The harmonic generation mechanism of frequency converter is because of the non-linearity of frequency converter, including two parts: rectifier and inverter. For a simple example, the streams we see are, if there is no wind, and the bottom is flat, then there will be no waves, no ripples. This is because the water flows through the region is linear. Because of the fact that the wind and the water are not flat enough, these nonlinear conditions lead to waves and ripples.
