Power supply inverter and power supply phase detection circuit thereof

Abstract

The invention relates to a power supply inverter and a power supply phase detection circuit thereof. The power supply phase detection circuit comprises a low-pass filter circuit and a phase discrimination circuit, wherein the low-pass filter circuit is used for filtering power-grid voltage signals containing harmonic waves, the phase discrimination circuit is used for acquiring an accurate power supply phase by detecting a zero crossing point of a power-grid voltage phase detection signal with the same phase as that of a power-grid voltage fundamental wave signal, and supplying the power supply phase to a control circuit of the power supply inverter; and the power supply phase detection circuit further comprises a phase-shift circuit, wherein the phase-shift circuit is arranged at the front end of the low-pass filter circuit or between the rear end of the low-pass filter circuit and the phase discrimination circuit, and after the power-grid voltage signal containing the harmonic waves passes through the low-pass filter circuit and the phase-shift circuit, the power-grid voltage phase detection signal with the same phase as that of the power-grid voltage fundamental wave signal is acquired and supplied to the phase discrimination circuit. By adoption of the power supply inverter and the power supply phase detection circuit thereof in the invention, the correct power-grid voltage detection phase can be acquired while the low-order harmonic waves are filtered and removed, and a power-grid access phase sequence is unconcerned.

Description

technical field [0001] The invention relates to the field of motor speed regulation and energy saving, in particular to a power inverter device and a power supply phase detection circuit for motor speed regulation and energy saving. Background technique [0002] The block diagram of the system structure of the power inverter device commonly used in industry, such as figure 1 As shown, no matter which control theory is adopted, the basic working principle is that the control circuit triggers the on-off of the power electronic components in the power circuit by detecting the phase of the grid power supply, so as to realize the flow of DC current to the AC grid. When the current phase and When the grid voltage phase difference is greater than 90 degrees, the energy is sent back to the grid. [0003] The power phase detection circuit is the key to realize the correct return of energy to the power grid. Usually, it consists of transformers, filters and the final phase detection ...

AI Technical Summary

Problems solved by technology

However, when the phase sequence of the three-phase power supply is incorrectly connected to the device, the output side of the phase-shifting transformer may be a leading or lagging power phase waveform, which causes the filtered signal to fail to reflect the phase sequence of the power supply normally, so an additional phase sequence is required The detection circuit judges the phase sequence. If it is not correct, the three-phase input power wiring of the device must be adjusted. Because there are many combinations, only one is correct, which brings great inconvenience to actual use.

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