Voltage zero-crossing point obtaining method and device

The invention discloses a voltage zero-crossing point obtaining method and device. The voltage zero-crossing point obtaining method comprises the following steps: obtaining voltage sampling signals; determining fundamental wave initial phase of the voltage sampling signals according to the voltage sampling signals; obtaining initial phase change between adjacent two power frequency periods to obtain practical period parameters; and determining the voltage zero-crossing point according to the practical period parameters and the fundamental wave initial phase. Through the voltage zero-crossing point obtaining method and device, the problem of inaccuracy of determining the voltage zero-crossing point in the prior art is solved, and thus the effect of improving the accuracy of determining the voltage zero-crossing point is improved.