METHOD FOR AUTOMATIC CONTROL OF INSULATION RESISTANCE OF DC NETWORK Russian patent published in 2021 - IPC G01R27/18 G01R15/12 

FIELD: control and measuring equipment.

SUBSTANCE: invention relates to a control and measuring equipment for vehicles with a DC power supply system. In the method, voltages are measured and the results of measuring the voltage U +, U- between the corresponding positive and / or negative power lines and ground are recorded, for this, after the complete discharge of the capacitor C, the first switching element K1 is turned off, which provided a complete discharge of the capacitor C through the discharge resistor R_D “to ground” , then the second switching element K2 is switched on for a fixed time t, providing the capacitor C is charged from an arbitrarily selected power bus through an additional resistance R_A and the corresponding insulation resistance R_i, for a predetermined charge time, after the second switching element K2 is turned off, the charge of the capacitor C is interrupted, the charge voltage U_C of the capacitor C is measured and, after fixing the measurement results, one should turn on the first switching element K1 of the discharge circuit of the capacitor C to ground through the discharge resistor R_D to bring the measuring circuit to its original position and readiness for repeated measurement, and the values of the insulation resistance are calculated by the following ratios:

where: R_i+, R_i- - insulation resistance of the positive and negative supply buses, respectively; U₊, U_- - voltages on the positive and negative power lines relative to "ground" before the start of the charge cycle of the capacitor C; U_C is the voltage across the capacitor charged during the measurement; C is the capacitance of the capacitor; t is the charging time of the capacitor; R_A is the resistance of an additional resistor in the capacitor charging circuit. Next, the calculated values are compared in the control unit with the resistance values from previous measurements and, if these values do not exceed the standard changes in the values, these values are recorded in the parameter fixing unit until the next measurement and calculation cycle.

EFFECT: increasing the accuracy of measurements of the insulation resistance of the DC network, increasing the electrical safety of operation and increasing the noise immunity.

1 cl, 1 dwg