Alternate current network phase change detection and compensation system and method

Abstract

The invention discloses an alternate current network phase change detection system which comprises a coordinate transformation device and a phase change detection device. The coordinate transformation device receives a one-phase or multi-phase network voltage feedback signal and generates a first voltage component signal and a second voltage component signal under a stationary coordinate. The phase change detection device receives the first voltage component signal and the second voltage component signal, and calculates out a phase deviation signal which represents the phase change which exists in the one-phase or multi-phase voltage feedback signal at least based on the first voltage component signal and the second voltage component signal. The invention further discloses an alternate current network instantaneous phase angle generation system, an energy conversion system, a photovoltaic energy conversion system, a phase change detection method and a phase change compensation method.

Description

technical field [0001] The embodiments disclosed in the present invention relate to an energy conversion system and method, in particular to a system and method for detecting and compensating for phase changes in an AC grid. Background technique [0002] Generally speaking, in an energy conversion system, such as a renewable energy energy conversion system, a phase locked loop (Phase locked loop, PLL) device is usually used to perform synchronous control between the energy conversion system and the power grid. figure 1 A conventionally used phase locked loop arrangement is shown. figure 1 The illustrated PLL device 120 includes a coordinate conversion unit 114 for converting the three-phase grid voltage signal 112 into a d-axis voltage signal (not shown) and a q-axis voltage signal 116 in the d-q coordinate system. The q-axis voltage signal 116 is provided to a summation element 118 , which subtracts the zero voltage command signal 122 from the q-axis voltage signal 116 to ...

AI Technical Summary

Problems solved by technology

However, when a transient event or a fault occurs in the power grid, there may be a large phase change in the grid voltage 112, and the q-axis voltage signal 116 is not zero at this time

In this case, due to the slow response speed of the control loop of the PLL device 120, the PLL device 120 may not be able to quickly provide the correct phase information of the grid voltage

Controlling with wrong phase information may result in reversed power flow from the grid to the energy conversion system

This reversed power flow may damage the semiconductor devices in the energy conversion system, and cause power imbalance problems, and cause the DC bus of the energy conversion system to be under greater voltage stress

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