Method and device for measuring rail voltage based on crank angle in high-voltage co-rail system

The invention relates to a method and a device for measuring rail voltage based on crank angle in a high-voltage co-rail system. The method comprises the following steps: carrying out filtration on the actual rail voltage measured in real time to form input rail voltage; sampling the input rail voltage in a predefined crank angle interval to form a sampling signal; selecting the sampling signal positioned in a rail voltage stable region of the high-voltage co-rail system as a characteristic sampling point of the rail voltage; and carrying out filtration on the characteristic sampling point toform a measurement value of the rail voltage. The device comprises an input rail voltage forming device, a sampling signal forming device, a characteristic sampling point selector, and a rail voltagesignal generator, wherein the input rail voltage forming device is used for carrying out filtration on the actual rail voltage measured in real time to form the input rail voltage; the sampling signal forming device is used for sampling the input rail voltage in the predefined crank angle interval to form the sampling signal; the characteristic sampling point selector is used for selecting the sampling signal positioned in the rail voltage stable region of the high-voltage co-rail system as the characteristic sampling point of the rail voltage; and the rail voltage signal generator is used for carrying out filtration on the characteristic sampling point to form the measurement value of the rail voltage.